184637033 GBA Flare Systems

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(1)GBA Ltd Burnham House 93 High Street Burham SL1 7JZ England. GBA Srl Via Ramazzotti, 24 20052 MONZA Milan Italy. GBA-Corona Inc. 10333 Harwin Suite 110, Houston Texas 77036 USA. Tel.: +44-(0)1628-610100 Fax.: +44-(0)1628-610170 E-Mail: [email protected]. Tel.: +39-039-492718 Fax.: +39-039-2494257 E-Mail: [email protected]. Tel.: +1-713-773-9933 Fax.: +1-713-773-9940 E-Mail: [email protected].

(2) COMPANY PRODUCT MANUAL Page 1. 1. ONSHORE FLARE SYSTEMS. ................................................................. 4 1.1. 1.2. 1.3. 1.4.. INTRODUCTION....................................................................................................................................................4 FLARE TYPES AND APPLICATION....................................................................................................................4 FLARE SYSTEM DESIGN. ....................................................................................................................................6 KEY COMPONENTS..............................................................................................................................................6. 2. PRODUCT LISTING AND ENGINEERING CAPABILITIES. .......... 13 2.1. 2.2. 2.3. 2.4. 2.5. 2.6. 2.7. 2.8. 2.9. 2.10. 2.11. 2.12.. GENERAL. ............................................................................................................................................................13 DESIGN CAPABILITIES......................................................................................................................................13 DESIGN AND SUPPLY OF INTEGRATED FLARE SYSTEMS........................................................................13 DESIGN AND SUPPLY OF FLARE TIPS AND BURNERS...............................................................................14 FLARE CONTROL AND SAFETY SYSTEMS. ..................................................................................................14 TECHNICAL DESIGN CONSULTANCY SERVICES........................................................................................14 INSTALLATION/ERECTION. .............................................................................................................................14 COMMISSIONING. ..............................................................................................................................................14 MAINTENANCE...................................................................................................................................................14 DESIGN AND SUPPLY OF STEEL STRUCTURES...........................................................................................15 DESIGN AND SUPPLY OF VESSELS, HEAT EXCHANGER, STORAGE TANKS. .......................................15 PIPING DESIGN ...................................................................................................................................................15. 3. EQUIPMENT AND PRODUCTS. ............................................................ 17 3.1. PROPRIETARY FLARE TIPS. .............................................................................................................................17 3.1.1. HIGH PRESSURE SONIC FLARE TIPS....................................................................................................18 3.1.1.1. 3.1.1.2. 3.1.1.3.. General. ................................................................................................................................................................18 GBA CSF Flare Tip (Sonic). ...............................................................................................................................19 GBA VSF Flare Tip (Sonic). ...............................................................................................................................20. 3.1.2. PIPEFLARES...............................................................................................................................................21 3.1.2.1. 3.1.2.2.. General. ................................................................................................................................................................21 GBA PF Series Pipeflare. ....................................................................................................................................22. 3.1.3. STEAM ASSIST FLARES. .........................................................................................................................23 3.1.3.1. 3.1.3.2. 3.1.3.3. 3.1.3.4.. General. ................................................................................................................................................................23 GBA GCT - Flare Tip..........................................................................................................................................24 GBA GAJ - Flare Tip. .........................................................................................................................................25 GBA GCT-AJ Flare Tip. .....................................................................................................................................27. 3.1.4. AIR FLARES...............................................................................................................................................29 3.1.4.1.. GBA CAF Airflare...............................................................................................................................................29. 3.1.5. OFF-SHORE BURNER...............................................................................................................................30 3.1.5.1.. Seafire Burner and Boom. ...................................................................................................................................30. 3.2. PURGE EQUIPMENT AND SEALS. ...................................................................................................................31 3.2.1. MOLECULAR SEAL. .................................................................................................................................32 3.2.2. AIR LOCK SEAL. .......................................................................................................................................32 3.2.3. COMPARISION OF MOLECULAR AND AIR LOCK SEALS. ...............................................................33 3.3. WATER SEALS AND KNOCK-OUT DRUMS....................................................................................................34 3.3.1. Water Seal. ...................................................................................................................................................34 3.3.2. Knock-Out Drum. ........................................................................................................................................35 3.4. FLARE PILOT AND IGNITION SYSTEMS. .......................................................................................................36 3.4.1. Flame Front Generator. ................................................................................................................................37 3.4.2. Natural Draft Flame Front Generator. ..........................................................................................................38 3.4.3. CHT High Energy Electric Ignition Pilot .....................................................................................................39 3.4.4. DESI Direct Electric Spark Ignition............................................................................................................40 3.5. STEAM CONTROL AND MONITORING SYSTEMS. .......................................................................................41 3.6. STRUCTURES. .....................................................................................................................................................42 3.6.1. Guy Wire Supported Stacks .........................................................................................................................43 3.6.2. Derrick Supported Stacks.............................................................................................................................44 3.6.3. GBA Demountable Flare..............................................................................................................................45 3.7. TYPICAL P&ID’S..................................................................................................................................................50. GBA PRODUCT MANUAL Rev 2004.

(3) COMPANY PRODUCT MANUAL Page 2. 4. FLARE RADIATION CALCULATIONS AND TECHNIQUES.......... 52 4.1. 4.2. 4.3. 4.4. 4.5.. RADIATION ISOPLETHS. ...................................................................................................................................52 THERMAL RADIATION PLOT. ....................................................................................................................................53 SINGLE AND MULTI TIP ONSHORE INSTALLATIONS. ...............................................................................54 OFFSHORE INSTALLATIONS............................................................................................................................55 HORIZONTAL BURNPIT INSTALLATIONS. ...................................................................................................56. 5. COMPANY PROFILE............................................................................... 58 5.1. GENERAL. ............................................................................................................................................................58 5.2. EXPERIENCE PROFILE OF KEY ENGINEERING STAFF..................................................................................................58 5.3. FABRICATION SHOP CAPABILITIES...............................................................................................................61 5.3.1. Fabrication Plant Address. ...........................................................................................................................61 5.3.2. Available area. .............................................................................................................................................61 5.3.3. Workforce. ...................................................................................................................................................61 5.3.4. Tools and Plant.............................................................................................................................................62 5.3.5. General.........................................................................................................................................................62 5.3.6. Welding........................................................................................................................................................62 5.4. SUB-SUPPLIERS. .................................................................................................................................................63 5.4.1. Fabrication. ..................................................................................................................................................63 5.4.2. Electrical / Ignition Panels. ..........................................................................................................................63. 6. LIST OF INDUSTRIAL CODES AND STANDARDS USED BY GBA.66 7. MAIN CUSTOMER LIST. ........................................................................ 68 8. INTERNATIONAL USERS REFERENCE LIST. ................................. 70. GBA PRODUCT MANUAL Rev 2004.

(4) COMPANY PRODUCT MANUAL Page 3. ONSHORE FLARE SYSTEMS A GENERAL DISCUSSION.. GBA PRODUCT MANUAL Rev 2004.

(5) COMPANY PRODUCT MANUAL Page 4. 1. ONSHORE FLARE SYSTEMS. Onshore Flare Systems generally operate at pressures near atmospheric and are often used to flare gases that produce smoke when burnt in any quantity. This basically encompasses flares on refineries, chemical plants, oil and LPG terminals, etc.. 1.1. INTRODUCTION. The flare is a key component of the closed emergency release system in a refinery or chemical plant. Emergency releases originating from safety valves, vapour blow downs, process stream diversion and equipment drainage, which cannot be discharged directly to the atmosphere for reasons of safety or pollution control, are routed through closed systems to a blow down drum where liquids and vapours are separated. The flare provides a means of safe disposal of the vapour streams from these facilities, by burning them under controlled conditions to ensure that adjacent equipment or personnel are not exposed to hazard. In addition pollution control and public relations requirements must be met. A typical refinery flare will use several utilities when in operation power, steam, fuel gas. The careful design, operation and maintenance of the flare system can minimise the costs of these expensive utilities.. 1.2. FLARE TYPES AND APPLICATION. In general there are three types of flares available for onshore use:. a) The elevated flare; b) The groundflare; c) The burn pit flare. Although the three basic designs differ considerably in required capital and operating costs, selection is based primarily on pollution and public relations considerations, i.e. smoke, luminosity, air pollution, noise and available space.. a) Elevated Flares. Elevated flares are the simplest and most widely used, offering safe and efficient combustion of waste gases with varying degrees of smokeless burning. By the use of steam injection and effective tip design, heavy hydrocarbons can be burnt smokelessly. Steam injection, used to reduce smoke pollution, introduces a source of noise, and a compromise between smoke reduction and noise is usually necessary. If correctly designed the elevated flare provides the best dispersion characteristics for malodorous and toxic combustion products and is the general choice for either total flare loads, or for handling over-capacity releases in conjunction with a ground flare. For most applications, the elevated type is the only acceptable means of flaring "dirty gases", i.e. gases high in unsaturates, hydrogen sulphide or those that have highly toxic combustion products. Structures. Three types of support methods for elevated flares are used:. GBA PRODUCT MANUAL Rev 2004.

(6) COMPANY PRODUCT MANUAL Page 5. a) Guyed - this type of structure is usually the least expensive to build but in some cases the guy wires result in restrictions on the use of adjacent land in addition to normal spacing restrictions. b) Derrick - this type of structure is well suited for tall structures subject to strong winds or where large thermal ranges are expected. The structure can be designed such that the flare stack may be demounted for maintenance purposes, removing the requirement for plant shutdown if the flares are arranged as duty/standby. c) Self-Supporting - this type of structure is designed so that the flare riser pipe has no lateral structural support. For short flares, this is the least expensive system to erect and maintain. b) Groundflares. Various designs of proprietary ground flare are available. Smokeless operation can generally be achieved (with or without assist media depending on design), with essentially no noise or luminosity problems, provided that the design rate to the flare is not exceeded. However, since the flame is near ground level, dispersion of stack releases needs to be carefully considered. The ground flare is suitable for "clean" gases (i.e. where toxic or malodorous concentrations are unlikely to be released through incomplete combustion or as combustion products), offers very low noise characteristics and reduces the visual effect of a flame, which is concealed at all times. It should not be used in locations upwind of adjacent residential areas. Generally, it is not practical to install a ground flare large enough to burn the maximum release load, and the usual arrangement is in combination with an elevated relief flare. The latter is normally provided with steam injection, but smoke may be accepted during the small number of major releases.. c) Burn Pit Flares. The burn pit is of simple construction, with low capital and operating costs, and can handle liquid as well as vapour hydrocarbons. The sizing of pit flare systems is essentially the same as for pipe flares without the knockout drum. The flare header should slope down to the pit to allow full drainage of liquids. The flare pit will be sized for the largest flame length, taking account of thermal rise, and the predicted volume of liquids to be held. The pit should slope away from the flare tip and the pit orientation should minimise wind blowing into the flare tip. Remotely ignited pilot burners are essential for the protection of personnel due to the possibility of unburnt hydrocarbons remaining within the pit bund. There is no means of controlling emission from a low-pressure flare and as such their use should be limited.. GBA PRODUCT MANUAL Rev 2004.

(7) COMPANY PRODUCT MANUAL Page 6. 1.3. FLARE SYSTEM DESIGN. Flare Capacity and Sizing. Flare systems are designed to handle the largest vapour release from safety valves, vapour blow downs and other emergency relief systems. Normally the flare will be sized following a plant hazard analysis and is a function of maximum allowable backpressure on safety valves and other sources of release into the emergency systems. Flare design must consider the pressure drop through the relief headers, knockout drums, flare header, seal drum, stack riser, purge seal and flare tip. In accordance with API RP 521 recommendations, tip exit velocity at maximum relief should be limited to 0.5 Mach to ensure stability and limit excessive noise. For pressure drops through proprietary flare tips and allowable exit velocities, which may be greater than 0.5 Mach, flare vendors should be approached. For some gas compositions exit velocity may need to be restricted due to high flame speed (hydrogen) or low heating value gases (ammonia and gases rich in inert).. Flare Location and Height. The location and height of an elevated flare will be predominantly based on radiation. In some instances dispersion of toxic gases from a lit or unlit flare may be controlling. Radiation limits are generally based on personnel tolerance rather than equipment tolerance to heat, as the former levels are considerably lower. In lower latitude regions, solar radiation will need to be considered as an additive to flare radiation and hence flare height or sterile boundary will be increased compared with plants in higher latitudes. The generally accepted radiation limits are: 500 Btu/h.ft2 (1,6 kW/m2) for continuous working And 1.500 Btu/h.ft2 (4,7 kW/m2) for emergency access only.. 1.4. KEY COMPONENTS. The basic components of an elevated flare system can be summarised as follows:. a) b) c) d) e) f) g). Flare tip; Air ingress seal; Stack riser and structure; Water seal; Knock-out drum; Means to control smoke emissions; Ignition system.. a) Flare Tip. There are a number of different designs of flare tip available: • Pipeflare tips; • Steam flare tips; • High pressure sonic flare tips; • Air blown flare tips.. GBA PRODUCT MANUAL Rev 2004.

(8) COMPANY PRODUCT MANUAL Page 7. GBA ENGINEERING AND CONSTRUCTION HAVE A COMPLETE RANGE OF FLARE TIPS TO SUIT ALL CONDITIONS. THESE ARE COVERED EXTENSIVELY WITHIN THIS DOCUMENT. Pipe flares are the most commonly used general-purpose tips, but do not provide any degree of smokeless combustion unless the gas is predominantly methane and has a molecular weight less than 20. For smokeless combustion the simplest and most common type of tip, which uses steam as a smoke suppressant, is the generic 'Crown of Thorns' tip which injects steam through a number of nozzles located on a manifold positioned around the circumference of the tip. Other types use the ejector principle to premix air into the steam through a manifold at the base of the tip. The pre-mixed phase then flows through a number of internal tubes within the tip, emerging to mix co-currently with the flare gas. This type of tip is more efficient than the 'Crown of Thorns', operates with lower noise characteristics and provides a greater extent of smokeless capacity. Where steam is not available, air blown flares will provide a percentage of smokeless burning. The tip incorporates a series of flow vanes designed to maximise the mixing of flare gas and primary air provided by a blower / fan included as part of the flare system. Where the relief gas is at high pressure (mainly available on offshore oil and gas production platforms) the driving force of the gas may be used to promote smokeless combustion at sonic velocities. For turndown conditions, consideration is given to the design of a variable slot tip, which will ensure smokeless combustion at relief rates from maximum to purge.. b) Air Ingress Seals and Purging. Flare systems are subject to potential flashback and internal explosion since flammable vapour / air mixtures may be formed in the stack or inlet piping by the entry of air. The pilot constitutes a continuous ignition source. Flares may be provided with flashback protection, which prevents a flame front from travelling back to the upstream piping and equipment, or may be positively purged with hydrocarbon or inert gas to ensure a non-flammable atmosphere within the stack. The most common cause of a stack explosion is where air has entered the plant and has passed through the flare header as an explosive mixture. Depending on the application and client preference elevated flare stacks may be fitted with a molecular seal (also known as the labyrinth seal) or fluidic seal. The molecular seal uses the density differences between the purge gas and air to produce a barrier against air infiltration. It has become apparent in the last few years that purge rates can be reduced to comparable levels of molecular seals just by using a simple fluidic type seal. This latter type uses the velocity of the purge gas to pick up and carry out any air that diffused into the tip. The use of a velocity seal (GBA type Air Lock Seal) is generally preferred due to its low cost, minimal restriction to flow and its absence of impact on structural design. It is interesting to note that work on tall elevated stacks evaluating the effectiveness of various purge rates, shows that the correlation derived by Husa can significantly underestimate the required purge gas rate in the unlit condition, but it should also be noted that as soon as the purge is lit, oxygen levels measured 6m down the stack fall to near zero, indicating that the infiltrating air is being used in the combustion of the purge gas - probably internally.. GBA PRODUCT MANUAL Rev 2004.

(9) COMPANY PRODUCT MANUAL Page 8. c) Stack Riser and Structure. Many varieties of structures have been used for flare stack support, but the most common is the guyed stack, which is generally the lowest cost option. Heights of up to approximately 150m have been successfully employed, although these are few, most refinery stacks being in the 60-100m ranges. A limitation for guyed stacks is the range of process temperature encountered when in service. This variation in temperature will cause the stack to expand and contract with resultant stretching or loosening of the guy wires. A service range of 200 to 300°C is usually limiting in this case. In the event of an excessive temperature variation, a guyed derrick can be used or even a freestanding derrick structure. A structure offering great operational flexibility is the jack-up derrick. This allows flares and risers to be dismounted for replacement and / or repair while a second flare system remains on-line. No plant downtime is necessary. This is a system much favoured by certain operators and is one that GBA are extremely experienced with, having built three of the worlds largest systems (204m) in Antwerp, Belgium.. d) Water Seals. Water seals are used to provide a positive seal against air ingress and flashback, and also to maintain the upstream header at a positive pressure. Water seal drums can either be horizontally or vertically mounted and must be correctly sized to prevent water carryover through the flare stack under normal operating conditions. Under emergency conditions it must be expected that the water will be carried away by the high flare gas velocities. Fast water makeup is therefore important to maintain the seal integrity. A common problem with water seals is one of pulsation caused by water moving from side to side, causing the gas flow to vary periodically with time, (the period is generally about 1 second). This causes the flare flame to rise and fall, and also the flare noise to fluctuate. The internal design of the seal requires considerable attention with a variety of designs put forward by vendors. GBA has had considerable success in eliminating this problem by use of a 'Seebold' baffle and by using a 'saw-tooth' arrangement on the end of the dip leg.. e) Knockout Drums. Knockout drums are designed to remove liquid droplets of excessive size from the gas stream and to return the collected liquid to the process/drain. Sizing to API RP-521 recommendations is generally adequate but the knockout drum should be sited as close as practically possible to the flare stack and should not possess any internals liable to blockage.. f) Steam Control System Accurate control of steam supply to a steam flare is desirable. GBA PRODUCT MANUAL Rev 2004.

(10) COMPANY PRODUCT MANUAL Page 9. (i) (ii) (iii) (iv). To minimise smoke emission; To minimise noise emission; To minimise steam consumption; To avoid over-steaming and subsequent loss of flame.. Traditionally, the steam flow is retied to gas flow and if the composition of the gases is subject to change, a density measurement for ratio correction is also required. These types of systems are of minimal success because flow measurement is difficult due to the low velocity of the gases. The density measurement is equally difficult because the gases are sometimes corrosive and always dirty. Maintenance and downtime on this type of system is very high. Because of these problems, it is typical to find the steam valve manually loaded to 60% or higher, to protect against the flare smoking, which results in a tremendous waste of expensive steam. Closed circuit television is sometimes used for steam control. A television camera is installed in the field, aimed at the flare tip with a screen in the control room for operator viewing. The unit operator should occasionally glance at the screen and manually adjust the steam flow. Since the operator may not be checking the operation of the flare continuously, manual steam flow is normally much greater than required, to insure that small upsets do not create a smoking condition. A number of optical infrared monitors are available which will provide a fully automatic closed-loop control of steam to avoid smoke formation. The infrared monitor used by GBA measures the radiant flux density from hot gaseous combustion products and from particles of carbon. The monitor measures the flare's tendency to smoke and hence can ensure steam is delivered before smoke formation. The advantages of an infrared flame monitor are:. Control is not affected by flare gas composition and discharge velocity; Fast response time; No gas flow or density device required; No component exposed to flare gas stream; Very low maintenance at accessible location.. g) Pilot Ignition System Almost without exception, flare pilot ignition is performed by using a flame front generation system. This method involves filling a small-bore pipe, which runs from the flame front generator panel to the flare tip, with a combustible gas / air mixture. The mixture is ignited by a spark in an ignition chamber on the panel, generating a flame front which travels to the pilot and lights it at the tip. This technique is well known, and established throughout the industry. However its performance is affected by a number of factors which combine to present problems in the field making it unreliable i.e.. GBA PRODUCT MANUAL Rev 2004.

(11) COMPANY PRODUCT MANUAL Page 10. (i) Flame front lines always collect large quantities of water, which require draining before ignition; (ii) Changes in fuel gas compositions and the use of wet air conspire to defeat operators; (iii) Long term pipe corrosion and lack of maintenance reduce the probability of a good ignition. Electric pilot ignition systems have been developed to overcome the problems of the flame front ignition system. GBA have developed the CHT System using a direct electric ignition flare pilot. Using this technique, the pilot flame is lit directly from a High Energy spark generated adjacent to the pilot nozzle. The ignitor can be powered from any available mains AC supply or even from low voltage DC supplies and is offered for use in either safe or explosion proof classified areas.. Groundflares In most cases the economics of providing a groundflare sized to handle the entire release from the largest design contingency are prohibitive, due to the low frequency of occurrence of such major releases. Instead it is designed to handle a proportion of the flow so that releases up to this level will be smokeless and non-luminous. This will normally cover a large proportion of releases in a typical plant, but variations on this sizing basis may be dictated by considerations of the number and type of upstream process units, type and probability of major release contingencies, atmospheric pollution restrictions and cost of the flare facilities. An over-capacity line to an elevated flare is provided to handle the excess flow when the flaring rate exceeds the capacity of the groundflare. The over-capacity line and flare is normally designed to handle the entire maximum flow such that it can allow the groundflare to be shut down for maintenance. In this arrangement the water seal described above acts as a "diverter valve" such that the gas will divert to the groundflare up to a predetermined pressure, set by the water height. Groundflares must be considered as a whole and not as a collection of parts. That is to say the enclosure, the burners, the air distribution, the location and the wind fence must all be designed to work in combination. It is pointless to have a highly efficient burner if the air distribution system does not succeed in supplying air to the burner.. Air Management System. Perhaps the key to good groundflare design is the overall air management system to draw air to the flare base, allowing the burners to induce an even flow, distributed uniformly. Basic vertical wind fences provide a degree of protection from wind blowing through the open base of the groundflare. This design however, produces eddies and uneven distribution across the combustion enclosure. Extensive wind tunnel testing has resulted in a wind fence of an inclined and louvered nature. The wind fence ensures even air distribution across the enclosure and control air flow to limit NOX formation.. GBA PRODUCT MANUAL Rev 2004.

(12) COMPANY PRODUCT MANUAL Page 11. Burner System. Most groundflare designs have an array of burners, which are staged to ensure even and complete combustion. Staging control is based on header pressure. Smokeless combustion often requires assist media such as steam or forced draft air at the burner head. The burner system utilised by GBA is a proprietary design, which does not require assist media. It produces a stable flame and provides for low emissions and low radiation, eliminating maintenance problems associated with cracking of hydrocarbons within the gas manifolds. Enclosure. Combustion takes place within a refractory lined enclosure of rectangular or circular section. The height is dependent upon the required combustion volume to ensure flames stay within the enclosure. Refractory lining will either be castable type or ceramic fibre blanket, the latter being preferred following extensive trials. The enclosure not only retains the flame from a visual point of view but also provides a barrier to noise. As such groundflares can be located very close to the plant with minimum sterile area.. GBA PRODUCT MANUAL Rev 2004.

(13) COMPANY PRODUCT MANUAL Page 12. PRODUCT LISTING AND ENGINEERING CAPABILITIES.. GBA PRODUCT MANUAL Rev 2004.

(14) COMPANY PRODUCT MANUAL Page 13. 2. PRODUCT LISTING AND ENGINEERING CAPABILITIES. 2.1. GENERAL. GBA employs over 40 personnel at its offices in London, Milan, and Houston comprising process, mechanical, structural and instrument engineers, CAD draughtsmen, QA/QC managers, inspectors and support staff in addition to qualified welders, fitters, construction crew and supervisors based at our fabrication plant in Parma. Each individual is highly qualified in their own field of expertise, and collectively, all employees ensure that GBA can offer a complete "turn-key" package covering process design, engineering, procurement, fabrication, project management, erection/ construction, commissioning and maintenance of our total product range as further described in this section. GBA has the capability to perform design and engineering using the most up-to-date networked AUTOCAD facilities and E-mail service, a project management department with international procurement experience, Quality Control management and inspectors all dedicated to ensuring quality and timely delivery of equipment.. 2.2. DESIGN CAPABILITIES. GBA provides a total "turn-key" project responsibility ensuring minimum cost and minimum risk to our clients. This responsibility includes, but is not limited to:-. a) b) c) d) e) f) g) h) i) j) k) l) m) n). Process design Engineering (mechanical, structural, instrument, control, electrical) Engineering draughting, CAD design Project management Procurement Planning Fabrication QA/QC Inspection Transportation/Shipping Construction/Erection Pre-commissioning/Commissioning Maintenance After sales service. 2.3. DESIGN AND SUPPLY OF INTEGRATED FLARE SYSTEMS. a) b) c) d) e) f) g). Derrick supported flares Derrick supported demountable flares Guy wire supported flares Self supported flares Enclosed ground flares Towers and booms for offshore flare installations Burn-pit flares. GBA PRODUCT MANUAL Rev 2004.

(15) COMPANY PRODUCT MANUAL Page 14. 2.4. DESIGN AND SUPPLY OF FLARE TIPS AND BURNERS. a) b) c) d) e) f) g) h). Pipe flare tips Steam assisted flare tips for smokeless combustion Air assisted flare tips for smokeless combustion Sonic high pressure flare tips Liquid/Condensate flare tips and burners LNG flare tips Ground flare burners Vent tips with high dispersion characteristics. 2.5. FLARE CONTROL AND SAFETY SYSTEMS. a) b) c) d) e) f) g). Ignition equipment Automatic Steam Control Purge equipment Water seal drums and instrumentation Knock-out drums and instrumentation Pumping skids Radiation and noise reduction systems. 2.6. TECHNICAL DESIGN CONSULTANCY SERVICES. a) b) c) d) e) f) g) h) i) j). Structural and mechanical design/drawings of derrick structures, towers and booms Maintenance and mechanical handling systems for both onshore and offshore applications Process and safety audits Radiation calculations and isopleths Thermal design and temperature profiles Noise calculations Emission calculations for both flare and vent systems Flare deck radiation/noise attenuation Design and development of detailed fabrication/erection drawings Erection and construction studies. 2.7. INSTALLATION/ERECTION. GBA employ their own construction and installation crew and will provide all labour, workforce and plant necessary to erect equipment supplied by GBA or others.. 2.8. COMMISSIONING. GBA employ their own team of engineers capable of providing on-site services for all your precommissioning and commissioning requirements.. 2.9. MAINTENANCE. GBA employ their own team of engineers, experienced and qualified to inspect existing plant and make recommendations on the need to repair, replace or continue to use equipment.. GBA PRODUCT MANUAL Rev 2004.

(16) COMPANY PRODUCT MANUAL Page 15. Our engineers will be pleased to undertake studies for replacing our own or competitors equipment and will be pleased to undertake all work necessary to change-out flare tips using our own labour and plant. GBA will also be pleased to conduct guy wire inspections on existing stacks and re-tension wires if it is felt necessary as part of an on-going maintenance program.. 2.10. DESIGN AND SUPPLY OF STEEL STRUCTURES. a) b) c) d) e) f) g). Steel structures for bridges Flying bridges Industrial structures Frameworks for steel buildings Lattice towers and masts for electrical lines and power cables Lattice towers and masts for telecommunications Design and development of detailed fabrication/erection drawings. 2.11. DESIGN AND SUPPLY OF VESSELS, HEAT EXCHANGER, STORAGE TANKS. a) Process, thermal and mechanical design with development of engineering drawings and specifications b) Development of detailed fabrication drawings c) Inspection and supervision. 2.12. PIPING DESIGN a) Piping process sizing including internal lining, sizing for temperature or other process requirements b) Piping layouts c) Stress analysis and support definition d) Fabrication isometrics e) General piping studies. GBA PRODUCT MANUAL Rev 2004.

(17) COMPANY PRODUCT MANUAL Page 16. EQUIPMENT AND PRODUCTS.. GBA PRODUCT MANUAL Rev 2004.

(18) COMPANY PRODUCT MANUAL Page 17. 3. EQUIPMENT AND PRODUCTS. 3.1. PROPRIETARY FLARE TIPS. GBA offer a comprehensive range of proprietary flare tips designed to handle the safe and efficient relief / disposal of gases discharged either from crude-oil production fields, gas fields, refineries, chemical and petrochemical plants or as by-products in Industry. GBA's philosophy is to ensure that the equipment is designed and fabricated to withstand the most arduous operating conditions of service, does not deteriorate in severe climatic conditions to which it is exposed, and operates at full efficiency within the levels of safety acceptable to the industry imposed by local authorities and environmental organisations. GBA's flares encompass a complete range of applications from low volume, low pressure to high volume, high pressure operation throughout the Oil and Gas Industry and are further described within this section.. a. High Pressure Sonic Flare Tips. b. Pipeflare Tips. c. Steam Assist Flare Tips. d. Air Flares.. GBA PRODUCT MANUAL Rev 2004.

(19) COMPANY PRODUCT MANUAL Page 18. 3.1.1. HIGH PRESSURE SONIC FLARE TIPS. 3.1.1.1. General. The safe disposal of gas from emergency depressurisation or blowdown operations is a major consideration for the designers of offshore oil and gas production platforms. Consideration of the flare or vent location must revolve around incident radiation on various parts of the platform, the flame path during changing process conditions, the risk of liquid carryover, and the gas plume in the event of flame-out. Based on the above, the flare tip selection is extremely important, and care must be taken in the evaluation of the type of technology for a particular application. GBA Sonic Flare Tips offer:. Low Radiation Characteristics : using single or multi jet configurations operating at high exit velocities to ensure efficient combustion by good air entrainment. Stability : achieved by using multiple jets and correctly designed and positioned pilot burners. Liquid Burning Capacity : any entrained liquid is atomised at high exit velocities and discharged from the jets co-axially with the relief gas. The residence time of the atomised liquid is sufficient to ensure complete combustion. No Blockage : single or multi jet open pipe configurations eliminate the possibility of blockage due to thermal distortion of the tip or debris carried in the relief gas stream. There are NO possibilities of mechanical blockage unlike other sonic flare technologies. Low Noise Characteristics : As gas discharges parallel with the flare tip, noise is directed away from the installation. Good Turndown Characteristics : Flexibility of operation is achieved from maximum relief to turndown without the use of mechanical devices. Process conditions from plant start-up through to emergency blow down can be accommodated using a single flare tip. Purge gas velocity increases with flare diameter. Therefore utilising multi-nozzles requires a lower purge than a single tip of equivalent area. Due to the high velocities used, the total area and therefore purge requirements is significantly reduced. Resistance to Wind : Due to the aeration of the flames and high gas velocities, deflection of the flame due to wind effect is slight.. GBA PRODUCT MANUAL Rev 2004.

(20) COMPANY PRODUCT MANUAL Page 19. 3.1.1.2. GBA CSF Flare Tip (Sonic). The GBA CSF is a single or multi-nozzle sonic high pressure flare tip designed to give superior performance where low thermal radiation and smokeless combustion is required. Its unique design of sonic nozzle channels the gas through a narrow annulus thereby maximising the gas / air interface and consequently entraining more CSF primary combustion air than Nozzles conventional tips. This translates into a highly pre-mixed flame that radiates Pilot Nozzle less and will be smokeless for a greater number of applications and flow conditions. Every effort has been made to ensure longevity in service and to this end the critical parts are all fabricated from thick wall heat resisting alloy. In addition, a slatted windshield works to minimise flame draw-down in windy conditions. For certain applications the GBA CSF flare tip is designed with multiple sonic nozzles. The use of multiple nozzles increases the gas / air interface area even further thus improving the overall flare tip performance in terms of even lower emitted radiation and shorter flame lengths. Critical items such as the flame retention lugs, pilot heads and all welded attachments in the heat affected zones are fabricated from high nickel alloys (310S) and are subject to rigorous and thorough inspection during manufacture.. Wind Shields. Ignition Manifold. Pilot Manifold. Inspirator Assembly. Pilot. Ignition. HP Gas. The tip is equipped with G-100 pilot Inlet Inlet Inlet burners that provide a constant and reliable source of ignition. Each pilot consists of a special high stability burner nozzle and a cast inspirator assembly designed to ensure correct secondary air requirements. Pilot gas and flame front ignition can be supplied either through individual lines or through distribution manifolds located at the base of the tip.. GBA PRODUCT MANUAL Rev 2004.

(21) COMPANY PRODUCT MANUAL Page 20. 3.1.1.3. GBA VSF Flare Tip (Sonic). The GBA VSF is a variable slot sonic high pressure flare tip designed to give superior performance where low thermal radiation and smokeless combustion is required under high turndown conditions. Its unique design of sonic nozzle channels the gas through a narrow annulus thereby maximising the gas/air interface and consequently entraining more primary combustion air than conventional Gas Slot tips. This translates into a highly pre-mixed Pilot flame that radiates less and will be smokeless Nozzle for most applications and flow conditions. Every effort has been made to assure longevity in service and to this end the critical parts are all fabricated from thick wall heat resisting alloys and in addition a slatted windshield Inner works to minimise flame draw-down in windy Wind Stack conditions. Shield The key to the GBA VSF's ability to deliver optimum performance over a wide range of operating flow rates lies in its unique ability to automatically vary the gas discharge slot width in response to changes in the flare gas flow rate. The GBA VSF is therefore not limited to a single slot geometry and adapts to a much wider range of operating conditions. At low flow rates the slot is positioned at its minimum setting, causing the back pressure to rise sufficiently to produce high discharge velocities which promote turbulent pre-mixed smokeless, low radiation combustion. The slot is normally configured to remain at minimum setting until a pressure of approx 0.7 barg is reached.. Spring Stack Ignition Manifold. Air Lock Seal. Inspirator Assembly Pilot Manifold. Pilot. Ignition. At this point, the slot starts to open linearly Inlet Inlet with increasing pressure until the maximum Gas Inlet slot is achieved at approx 1.80 barg. Once the maximum slot position is achieved, the tip behaves as a fixed slot version and gas flow increases directly proportional to the absolute inlet pressure (upstream density). Critical items such as the flame retention lugs, pilot heads and all welded attachments in the heat affected zones are fabricated from high nickel alloys (310S) and are subject to rigorous and thorough inspection during manufacture. The GBA VSF tip is fitted with G-100 pilot burners that provide a constant and reliable source of ignition. Each pilot consists of a special high stability nozzle cast in stainless steel material, gas/lines and cast inspirator assembly. Pilot gas and flame front ignition can be supplied either through individual lines or through distribution manifolds located at the base of the tip.. GBA PRODUCT MANUAL Rev 2004.

(22) VSF-12/3 Flare Tip Flow vs Pressure Curve: Low Flow, High MW 12000. 10000. Flow kg/h. 8000. 6000. 4000. 2000. 0 0.0. 0.1. 0.2. 0.3. 0.4. 0.5. Pressure barg MW= 58.08 Temp= 0.0°C. 0.6. 0.7. 0.8.

(23) VSF-12/3 Flare Tip Flow vs Pressure Curve: Case 2 120000. 100000. Flow kg/h. 80000. 60000. 40000. 20000. 0 0.0. 0.5. 1.0. 1.5 Pressure barg MW= 20.65 Temp= -40.0°C. 2.0. 2.5. 3.0.

(24) COMPANY PRODUCT MANUAL Page 21. 3.1.2. PIPEFLARES. 3.1.2.1. General. Traditionally, the pipeflare has been operated in the majority of flaring applications where hydrocarbon gas streams are burnt and where there are no restrictions of the production of smoke. Smoke will be generated to varying degrees depending on the molecular weight of the relief gas - the heavier the hydrocarbon, the more smoke will be generated. The main advantage of the pipeflare is its simplicity, robust construction, flexibility of operation and economy. Its applications can be found for duties associated with the following:. Offshore Oil and Gas Platforms Refineries Petrochemical Sites Production Fields Two phase combustion - horizontal burn pits.. GBA PRODUCT MANUAL Rev 2004.

(25) COMPANY PRODUCT MANUAL Page 22. 3.1.2.2. GBA PF Series Pipeflare. The GBA PF flare tip provides a flexible method of low pressure, high volume waste gas disposal utilising a well proven technology that ensures a safe and efficient means of combusting relief flow rates from maximum emergency conditions to turndown. Flame stability over the entire operating range is achieved by incorporating a series of flame retention lugs located around the periphery of the tip. This device stabilises the flame by Flame Retention creating a zone of re-circulating gas Lugs immediately downstream of the lugs and helps prevent lift-off. This together with the auxiliary stabilising effect of the purpose Pilot Nozzle designed pilots ensures maximum reliability under all wind conditions. The basic tip is of robust construction, fabricated from heat resistant stainless steel selected to avoid the requirement for additional refractory lining. Critical items such as the flame retention lugs, pilot heads and all welded attachments in the heat affected zones are fabricated from high nickel alloys (310S) and are subject to rigorous and thorough inspection during manufacture. To further enhance its operating life external wind deflectors are attached to the tip, designed to eliminate the low pressure zone created on the downwind side of the flare, which can cause flame impingement. These deflectors are fabricated in the form of slatted strakes and are manufactured from 310S stainless steel. The tip is equipped with G-100 pilot burners that provide a constant and reliable source of ignition. Each pilot consists of a special high stability burner nozzle, a cast inspirator assembly designed to ensure correct secondary air requirements, pilot gas and pilot ignition lines all fabricated from stainless steel.. Wind Shield. Ignition Manifold. Air Lock Seal. Inspirator Assembly Pilot Manifold. Ignition Inlet. Pilot Gas Inlet. Gas Inlet. Pilot gas and flame front ignition can be supplied either through individual lines or through distribution manifolds located at the base of the tip.. GBA PRODUCT MANUAL Rev 2004.

(26) COMPANY PRODUCT MANUAL Page 23. 3.1.3. STEAM ASSIST FLARES. 3.1.3.1. General. Most hydrocarbon containing relief gases tend to produce smoke when burnt unless sufficient oxygen is introduced into the zone of combustion. In particular, very low pressure gas streams and gases containing unsaturates are particularly prone to smoking due to the cracking and polymerisation that takes place in the core of the flame where flame temperatures are high and where there is insufficient oxygen for complete combustion. Smoke formation is often associated with high thermal radiation levels. Depending on the composition of hydrocarbon gas to be burnt, the extent of smokeless combustion required and the availability of steam as the medium to promote smokeless combustion, there are several types of flare tip available from GBA to meet your requirement. The simplest and most common type is that which features on upper steam manifold only, the GBA GCT series. This uses a number of injector nozzles located on a manifold positioned around the tip circumference to inject steam at high pressure directly into the flame. For applications where maximum efficiency and reduced emission is required, then it is preferable to use a tip that utilises internal steam/air tubes to improve performance. This type of tip pre-mixes air into the steam flow which then flows through a number of internal tubes within the tip emerging to mix co-currently with the flare gas, the GBA GAJ series. This method of injecting steam is more efficient than the upper ring of jets, is less noisy and provides a greater smokeless capacity. GBA offer a further extension to the smokeless capacity, which may be achieved by incorporating both upper, and lower steam injection facilities on the flare tip the GBA GCT-AJ series.. GBA PRODUCT MANUAL Rev 2004.

(27) COMPANY PRODUCT MANUAL Page 24. 3.1.3.2. GBA GCT - Flare Tip. The GBA GCT flare tip provides a flexible method of low pressure, waste gas disposal utilising a well proven technology that ensures a safe and efficient means of combusting relief flow rates from maximum emergency conditions to turndown. Flame stability over the entire operating range is achieved by incorporating a series of flame retention lugs located around the periphery of the tip. This device stabilises the flame by creating a zone of re-circulating gas immediately downstream of the lugs and helps prevent blow-off. This together with the auxiliary stabilising effect of the purpose designed pilots ensures maximum reliability under all wind conditions. Smokeless combustion is achieved with the GBA GCT flare tip through an upper steam manifold and a set of steam injection nozzles located around the circumference of the tip. These multi port nozzles are used to inject steam into the flame envelope with a degree of swirl, thus creating turbulence and inducing air into the flame. Steam Retention Pilot The steam also acts to cool the flame, thus Nozzle Lugs Head preventing thermal cracking of hydrocarbons and consequent smoke production. In Wind addition, a centre steam injector is used to Shield break up the central core of gas and to prevent burn-back. This type of steam injection is exceptionally simple to use and very flexible. Upper It will work effectively using steam of Steam Manifold virtually any quality/pressure. The basic tip is of robust construction, fabricated from heat resistant stainless steel selected to avoid the requirement for additional refractory lining. Critical items such as the flame retention lugs, pilot heads and all welded attachments in the heat affected zones are fabricated from high nickel alloys (310S) and are subject to rigorous and thorough inspection during manufacture. To further enhance its operating life and to optimise the operation of the steam nozzle, external wind deflectors are attached to the tip, designed to eliminate the low pressure zone created on the downwind side of the flare, which can cause flame impingement. These deflectors are fabricated in the form of slatted strakes and are manufactured from 310S stainless steel.. Centre Steam Nozzle Air Lock Seal Inspirator. Steam. Main Gas Inlet. Pilot Gas Flame Front. Each tip is equipped with G-100 pilot burners that provide a constant and reliable source of ignition. Each pilot consists of a special high stability burner nozzle, a cast inspirator assembly designed to ensure correct secondary air requirements, pilot gas and pilot ignition lines all fabricated from stainless steel. Pilot gas and flame front ignition can be supplied either through individual lines or through distribution manifolds located at the base of the tip.. GBA PRODUCT MANUAL Rev 2004.

(28) COMPANY PRODUCT MANUAL Page 25. 3.1.3.3. GBA GAJ - Flare Tip.. The lower steam manifold supplies a number of internal annular jet air inducers, which use the steam pressure to inspirate large quantities of air into the internal mixing tubes. The resulting steam / air mixture is ejected from the tubes into the core of the flame envelope where it mixes with the waste gases creating a turbulent smokeless flame.. Steam / Air Mixture. The GBA GAJ flare tip provides a flexible method of low pressure, high volume waste gas disposal utilising advanced technology that ensures a safe and efficient means of combusting relief flow rates from maximum emergency conditions to turndown. Flame stability over the entire operating range is achieved by incorporating a series of flame retention lugs located around the periphery of the tip. This device stabilises the flame by Retention Lugs creating a zone of re-circulating gas Pilot immediately downstream of the lugs Head and helps prevent blow-off. This together with the auxiliary stabilising effect of the purpose designed pilots Slatted ensures maximum reliability under Windshield all wind conditions. Smokeless combustion is achieved with the GBA GAJ through a lower steam manifold and a centre steam nozzle.. Lower Steam Manifold. Annular Steam Jet. This method of steam injection is not only more efficient than the GCT type, but it inherently generates less noise at source and also permits the use of an integral noise muffler which attenuates noise levels still further. A centre steam connection is provided to inject steam into the very centre of the flame core and also to act as cooling medium for the tip internals.. Centre Steam Lower Steam. Main Gas Inlet. Pilot Gas Flame Front. The basic tip is of robust construction, fabricated from heat resistant stainless steel selected to avoid the requirement for additional refractory lining. Critical items such as the flame retention lugs, pilot heads and all welded attachments in the heat affected zones are fabricated from high nickel alloys (310S) and are subject to rigorous and thorough inspection during manufacture. To further enhance its operating life, external wind deflectors are attached to the tip, designed to. GBA PRODUCT MANUAL Rev 2004.

(29) COMPANY PRODUCT MANUAL Page 26. eliminate the low pressure zone created on the downwind side of the flare, which can cause flame impingement. These deflectors are fabricated in the form of slatted strakes and are manufactured from 310S stainless steel. The tip is equipped with G-100 pilot burners that provide a constant and reliable source of ignition. Each pilot consists of a special high stability burner nozzle, a cast inspirator assembly designed to ensure correct secondary air requirements, pilot gas and pilot ignition lines all fabricated from stainless steel. Pilot gas and flame front ignition can be supplied either through individual lines or through distribution manifolds located at the base of the tip.. GBA PRODUCT MANUAL Rev 2004.

(30) COMPANY PRODUCT MANUAL Page 27. 3.1.3.4. GBA GCT-AJ Flare Tip.. Smokeless combustion is achieved with the GCT-AJ flare tip through the combined operation of an upper steam manifold (GCT) and lower steam manifold (GAJ), with a greater smokeless capacity than either the GCT tip or the GAJ tip.. Steam / Air Mixture. The GBA GCT-AJ flare tip provides a flexible method of low pressure, high volume waste gas disposal utilising advanced technology that ensures a safe and efficient means of combusting relief flow rates from maximum emergency conditions to turndown. Flame stability over the entire operating range is achieved by Steam Nozzle Retention Lugs Pilot incorporating a series of flame retention lugs located around the Head periphery of the tip. This device stabilises the flame by creating a Wind zone of re-circulating gas Shield immediately downstream of the lugs and helps prevent blow-off. This together with the auxiliary stabilising effect of the purpose Upper designed pilots ensures maximum Steam reliability under all wind Manifold conditions.. Lower Steam Manifold. Annular Steam Jet. This ensures greater flexibility over the complete operating range with regards to turndown and smokeless combustion at lower rates whilst maintaining low noise and efficient burning characteristics. It is preferable to primarily use the lower steam injection system, therefore steam control valving is often arranged so that the lower manifold valve is opened first and the upper manifold only opened if necessary.. Centre Steam. Main Gas The lower steam manifold supplies Upper Lower Pilot Gas Inlet a number of internal annular jet air Steam Flame Front inducers, which use the steam pressure to inspirate large quantities of air into the internal mixing tubes. The resulting steam / air mixture is ejected from the tubes into the core of the flame envelope where it mixes with the waste gases creating a turbulent smokeless flame. This method of steam injection is not only more efficient than the GCT type, but it inherently generates less noise at source and also permits the use of an integral noise muffler which attenuates noise levels still further.. GBA PRODUCT MANUAL Rev 2004.

(31) COMPANY PRODUCT MANUAL Page 28. The upper steam manifold increases the overall smokeless capacity through the use of an upper steam manifold and a set of steam injection nozzles located around the circumference of the tip. These multi port nozzles are used to inject steam into the flame envelope with a degree of swirl thus creating turbulence and inducing air into the flame. The steam also acts to cool the flame thus preventing thermal cracking of hydrocarbons and consequent smoke production. A centre steam connection is provided to inject steam into the very centre of the flame core and also to act as cooling medium for the tip internals. The basic tip is of robust construction, fabricated from heat resistant stainless steel selected to avoid the requirement for additional refractory lining. Critical items such as the flame retention lugs, pilot heads and all welded attachments in the heat affected zones are fabricated from high nickel alloys (310S) and are subject to rigorous and thorough inspection during manufacture. To further enhance its operating life, external wind deflectors are attached to the tip, designed to eliminate the low pressure zone created on the downwind side of the flare, which can cause flame impingement. These deflectors are fabricated in the form of slatted stakes and are manufactured from 310S stainless steel. The tip is equipped with G-100 pilot burners that provide a constant and reliable source of ignition. Each pilot consists of a special high stability burner nozzle, a cast inspirator assembly designed to ensure correct secondary air requirements, pilot gas and pilot ignition lines all fabricated from stainless steel. Pilot gas and flame front ignition can be supplied either through individual lines or through distribution manifolds located at the base of the tip.. GBA PRODUCT MANUAL Rev 2004.

(32) COMPANY PRODUCT MANUAL Page 29. 3.1.4. AIR FLARES. 3.1.4.1. GBA CAF Airflare. The GBA CAF range of flare tips is designed to provide for the smokeless combustion of low pressure gases where no process steam is available. Smoke is produced as a result of cracking and polymerisation at high flame temperatures when there is insufficient oxygen for complete combustion. Adequate aeration of the combustion zone reduces smoke which is achieved through the injection of primary air at the flare tip periphery, often supplied via a two speed centrifugal fan, located at the base of the stack. Smokeless combustion is promoted by incorporating a series of flow vanes within the tip, designed to maximise the mixing of flare gas and primary air at the point of exit. This mixing also ensures the stability of the main flame under extreme wind conditions and reduces thermal radiation levels at grade.. Pilot Nozzle. Mixing Vanes. Wind Shield. The GBA CAF air flare provides a flexible method of smokeless flaring utilising a well proven technology that ensures a safe and efficient means of combusting relief flow rates from maximum emergency conditions to purge. The tip is fabricated from high heat resistant stainless steel and comprises two concentric pipe sections, which channel primary air and flare gas into a mixing head located immediately below the tip exit. Air is directed over this head and mixes co-currently with the gas introduced into the radial vanes via a branch connection just above the main flare tip mating flange.. Ignition Inlet. Pilot Inlet. Air Inlet. Gas Inlet. The tip is equipped with G-100 pilot burners that provide a constant and reliable source of ignition. Each pilot consists of a special high stability nozzle, and cast inspirator assembly fabricated from stainless steel designed to ensure correct secondary air requirements, pilot gas and pilot ignition lines all fabricated from stainless steel. Pilot gas and flame front ignition can be supplied either through individual lines or through distribution manifolds located at the base of the tip.. GBA PRODUCT MANUAL Rev 2004.

(33) COMPANY PRODUCT MANUAL Page 30. 3.1.5. OFF-SHORE BURNER. 3.1.5.1. Seafire Burner and Boom. The GBA-SEAFIRE Burner is of well proven design using air as a medium device to atomize the liquid. Smokeless is achieved by direct-water injection into the flame. No fallout and no black carbon particles, thus no pollution and reduced heat radiation. The presence of solid particles in the liquid does not effect burning operations. Flame stability is guaranteed with the fitted INCOLLOY 800 cone. The burner head is installed on a support c/w rotating pivot and allowing rotation of 75° on each side of the boom centerline by using an hand winch from the foot of the boom. The SEAFIRE Burner is installed on a support boom. The support boom is made by tubular and includes the liquid, gas, air, diesel and water lines. The boom includes working platform around burner heads, a gangway for safe circulation along the boom, a base rotating pivot, a set of cables to support and to rotate the boom.. Water Manifold Burner Head Flexible Hoses. Liquid Pilot Gas Air Water Rotating Table. Pilot. Flare Gas. Gas Flare Burner Boom Structure. GBA PRODUCT MANUAL Rev 2004. Pilot.

(34) COMPANY PRODUCT MANUAL Page 31. 3.2. PURGE EQUIPMENT AND SEALS. Whenever the flare system is on-line, the flare tip, riser and main header must be maintained in a safe condition at all times. GBA recommend the provision of a continuous positive hydrocarbon or inert gas (nitrogen) purge dedicated to the flare under all conditions. Extensive development work by GBA has resulted in equipment designed to reduce purge rates and to provide a positive safeguard to the flare system in the unlikely event that purge gas is lost. Even though a flare system is not necessarily constantly flowing, the flare stack and relief header must be kept in a safe working condition at all times. This is achieved by the use of a continuous minimum flow of gas designed to prevent air being drawn into the flare system via the flare tip, or otherwise. This is known as the purge gas flow. Without a special flare seal device fitted the purge gas flow would need to have a velocity of between 0.3 to 0.6 m/sec to be effective. For a large diameter stack this can represent a significant amount of gas. To minimise this requirement, it is customary to use a proprietary seal device in the flare system located within, or close to, the flare tips.. There are two main types of gas seal currently available: i) The labyrinth type – (Molecular Seal) ii)The fluidic type – (Air Lock Seal) Both are installed immediately below the flare tip and both will prevent air ingress into the flare system provided a continuous purge gas is available.. GBA PRODUCT MANUAL Rev 2004.

(35) COMPANY PRODUCT MANUAL Page 32. 3.2.1. MOLECULAR SEAL. The Molecular Seal works by relying on the density difference between the purge gas and air. When the purge gas is lighter than air it forms a gas rich zone at the top of the seal that air cannot penetrate, conversely when the purge gas is heavier than air the seal is formed at the base of the device.. Outlet. In this way only a very low continuous purge flow is necessary to maintain conditions within the seal. A unique advantage of the molecular seal is that it will maintain safe conditions in the upstream riser for several hours in the event of a loss of purge gas.. Drain. Hand Hole. Inlet. 3.2.2. AIR LOCK SEAL. The Air Lock Seal (ALS) is a frustro-conical device, which is located as an integral part of the flare tip, welded within the main body of the tip just above the main flange. With all flare tip operations, under low relief conditions, air will slowly diffuse down the inside walls of the tip. The Air Lock Seal design acts to locally increase the velocity of purge gas through the seal, thereby moving any air back out of the tip. The Air Lock Seal is of simple rugged construction and has no moving parts, requiring the absolute minimum of maintenance.. GBA PRODUCT MANUAL Rev 2004. Air Lock Seal.

(36) COMPANY PRODUCT MANUAL Page 33. 3.2.3. COMPARISION OF MOLECULAR AND AIR LOCK SEALS. 1)The Molecular Seal prevents the ingress of air into the main flare system for a period of 2-4 hours (in the event of purge gas failure) due to the buoyancy effect discussed earlier. The Air Lock Seal has no hold-up capacity, therefore if purge fails, then the system is rapidly exposed to air ingress. 2)The Molecular Seal requires a purge rate of 0.003 m/sec. The Air Lock Seal requires a purge rate of approximately 0.012 m/sec (these are both based on flare tip exit area). Whilst the Molecular Seal requires a lower rate, the decrease could result in the flame burning within the flare tip reducing life time. 3)The Air Lock Seal has the following advantages: simple, open free path to atmosphere; no plugging; easy to install; offers no wind loading to the support structure. The Molecular Seal is heavy and adds considerably to the overall system weight increasing structural loads and increasing costs of the riser; no maintenance. If the Molecular Seal corrodes or is blocked, it has to be replaced requiring complete system shutdown; no drainage or corrosion problems. The Molecular Seal has the potential to corrode at its base and within its drain line, especially with sour gas relief; very low capital and installation costs. The Molecular Seal is expensive due to its size and complicated fabrication of the internal baffle arrangements. An extra drain line is required to grade. A full 360° inspection platform is also required for access to the drain and hand holes at the base of the Molecular Seal; can be used in a horizontal position i.e. burn pits and angled flaring for offshore applications. The Molecular Seal can only be used vertically. Summary. The Air Lock Seal is a simple low cost device with significant technical and commercial advantages over the Molecular Seal as described above. The use of Molecular Seals is quite uncommon now, as industry has recognised that they create more problems than they solve. Indeed the offshore oil production industry (North Sea – offshore UK/Norway/ Denmark) without exception uses Air Lock type seals instead of Molecular Seals due to structural and weight saving advantages of great significance in the design of offshore production facilities where weight and cost is at a premium.. GBA PRODUCT MANUAL Rev 2004.

(37) COMPANY PRODUCT MANUAL Page 34. 3.3. WATER SEALS AND KNOCK-OUT DRUMS. Water Seals and / or Knock-Out Drums may be designed as vertical vessels, in which case they can be incorporated at the base of the flare system, or as horizontal vessels located at a reasonable distance from the flare. It is however advisable to locate the vessels as close to the stack as possible to avoid condensate accumulation in the header between the drum and the flare.. 3.3.1. Water Seal. The Water Seal provides a positive means of flash-back prevention in addition to enabling the system header to operate at a slight positive pressure at all times. This is of use when an elevated flare is used in combination with another flare, or with a flare gas recovery system. The Water Seal vessel is fitted with a special saw-tooth dip leg and anti-pulsation baffle to minimise pulsing. The water level is preferably maintained by a constant overflow weir, in combination with a suitable 'S' bend drainpipe. Filling rates will be sufficient to re-establish the seal within 5 minutes if the seal is broken. The seal vessel may be equipped with an internal steam coil / sparger for winterisation purposes as required.. Flare Gas Inlet. Manway. Water Inlet Level Inst. Level Inst. WL Level Inst. Water Overflow. Level Inst. Steam In Steam Out. Drain. DIA. GBA PRODUCT MANUAL Rev 2004.

(38) COMPANY PRODUCT MANUAL Page 35. 3.3.2. Knock-Out Drum. Knock-Out Drums are designed to effectively remove hydrocarbon liquids from the main relief gas to prevent the possibility of carryover and "flaming rain" from the flare tip. The sizing of these vessels is generally based on the criteria defined in API RP 521 (Fourth Edition - March 1997) and considers residence time and drop out velocity of the liquid particles in the vapour flow. Since flare tips can handle small liquid droplets, the allowable vertical velocity in the drum may be based on that necessary to separate droplets from 300 microns to 600 microns in diameter (typically 450 microns). Knock-Out Drums will be designed to avoid the accumulation of hydrocarbon liquid and will be equipped with instrumentation and control to monitor liquid level and pump out facilities.. Flare Gas Outlet. Flare Gas Inlet. Manway Pressure Gauge Conn.. Temperature Inst.. Level Inst. Level Inst. LL Level Inst. Level Inst.. Drain. DIA. GBA PRODUCT MANUAL Rev 2004.

(39) COMPANY PRODUCT MANUAL Page 36. 3.4. FLARE PILOT AND IGNITION SYSTEMS. One of the main considerations for flare ignition is reliability of operation. An ignition system must be capable of fast performance and repeatability of use over and over again, under all environmental and operating conditions. GBA flare pilots and ignition systems are used throughout the world from the extreme cold of the Alaskan North Slopes to the intense heat of the Saudi Arabian desert and have experienced the arduous duties of the North Sea on oil and gas production platforms. Ignition Panels A complete range of ignition panels is available from GBA, designed for manual or automatic operation or a combination of both. These systems will ignite the GBA flare tip pilots from remote locations either through: 1) conventional Flame Front Ignition techniques or 2) High Energy ignition. GBA Pilots GBA standard G-100 pilots are offered on all types of GBA flare tips. The number and position of the pilots depends on the flare type and diameter. The pilot ignitor nozzles have been developed over many years of operational experience and offer maximum reliability of ignition and stability in winds in excess of 120mph (200 km/hr). The pilot ignitor nozzle and venturi mixing assembly is fabricated from alloy steels to ensure a long service life. For cases where pilot fuel gas has a high sour content, specialised alloys are used. GBA pilots are used in combination with all GBA ignition systems.. GBA PRODUCT MANUAL Rev 2004.

(40) COMPANY PRODUCT MANUAL Page 37. 3.4.1. Flame Front Generator. The basic GBA ignition panel is the Flame Front Generator (FFG). Flare pilots can be serviced through either individual flame front lines or via a splitter manifold located on the flare tip. Fuel gas and instrument air are supplied to the ignition chamber in the correct quantities via an on / off valve, needle valve and restriction orifice. The mixture is then ignited using an electric spark. The resulting flame front will travel down ignition line(s) to light each pilot either separately or through a splitter manifold. This flame front may be transmitted for distances of up to 1,000 metres along standard small bore pipework. The panel will continuously monitor the pilot burner flames via the installed thermocouples and should a failure be detected a visual alarm will be raised in the FFG and at the same time an alarm will be activated in the control room via remote contacts. The Flame Front Generator (FFG) is of free standing easel type construction fabricated from carbon steel. The framework will be open to atmosphere onto which is mounted the instrument and electrical enclosures certified for the specified area classification and weatherproof to IP65 (minimum). The panel will provide the functions of pilot ignition and monitoring of pilot status via thermocouples located in the pilot nozzle heads. HS Spark. PG Air in. Spark Plug Flame Front Outlet. ¾". Ignition Chamber PG Gas in. ½". The FFG is offered as a standard proprietary item of equipment and can be supplied for either manual or automatic operation or a combination of both. Pilot fuel gas and purge supply can be accommodated as a modification to the system if required.. GBA PRODUCT MANUAL Rev 2004.

(41) COMPANY PRODUCT MANUAL Page 38. 3.4.2. Natural Draft Flame Front Generator. In situations where compressed air is not available, the Natural Draft Flame Front Generator can be used. The principle of the Natural Draft FFG is straightforward. Fuel gas at moderate pressure is ejected through a small drilling forming the jet of a venturi inspirator. The action of the gas jet passing through the throat of the venturi causes a local drop in static pressure, which causes air to be drawn into the venturi intakes and mixed with the gas. The resulting gas/air mixture passes through an ignition chamber and via a length of 2" / 3" piping to the flame front connection of the flare pilot. In this way a continuous length of piping is filled with a flammable mixture which, when sparked in the ignition chamber will ignite and send a flame front through the 2" / 3" line to light the pilot. This is similar to a conventional FFG, which uses compressed air in lieu of an inspirator to achieve the same result. The other main advantage that the Natural Draft FFG has over the compressed air type is in its ease of use and its wide tolerance of set pressures. The Natural Draft HS HS FFG is normally set up to operate at a Spark certain fuel gas Open SOV Ignite pressure say, 25 psig. Experience has shown that typically the unit will still function correctly over about PG a 16 psi range thus, 2" or 3" SOV providing you set Fuel Flame the gas pressure Spark Gas Front Plug within the range 17In Outlet 33 psig, the system will work reliably! FILTER In addition, it is extremely IGNITION INSPIRATOR CHAMBER repeatable, when set VENTURI up in the above manner it will work first time every time! This certainly is not true of the compressed air type where air and gas pressure are critical to within a few psi and repeatability is difficult to achieve. GBA has the knowledge to design Natural Draft systems of up to 170m pipe run incorporating bends, fittings and splitter manifolds. The Natural Draft FFG is of freestanding easel type construction, fabricated from carbon steel. The framework will be open to atmosphere onto which is mounted the instrument and electrical enclosures certified for the specified area classification and weatherproof to IP65 (minimum). Flare pilots can be serviced through either individual flame front lines or via a splitter manifold located on the flare tip. The Natural Draft FFG is offered as a standard proprietary item of equipment and can be supplied for either manual or automatic operations, or a combination of both. Pilot fuel gas and purge supply can be accommodated as a modification to the system if required.. GBA PRODUCT MANUAL Rev 2004.

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