JET Module6_Bulk System

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version 1.0

JET Module 6

Bulk System

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T

ABLE OF CONTENTS

1 Introduction

pg 5

2 Principles of operation

pg 6

2.1 Purpose of a bulk system

pg 6

2.2 Basic bulk system components

pg 7

2.3 Principles of pneumatic conveying

pg 8

2.4 2.4 Principles of vacuum conveying

pg 13

3 Bulk systems

pg 14

3.1 Bulk storage tanks

pg 14

3.2 Pressure tank

pg 16

3.2.1 Components of pressure tank

pg 16

3.2.2 Weigh batch blender

pg 21

3.2.3 Additive/cutting bottle

pg 22

3.2.4 Bulk tank construction

pg 22

3.3 Gravity discharge bulk tanks

pg 24

3.3.1 Discharge valve

pg 25

3.3.2 Air supply line

pg 25

3.3.3 Aeration device

pg 25

3.3.4 Sight glass

pg 26

3.3.5 Weight indicator

pg 26

3.4 Pressurized surge can

pg 27

3.4.1 Vent line

pg 27

3.4.2 Pressure sensor

pg 27

3.4.3 Pneumatic controller

pg 28

3.4.4 Side discharge

pg 28

3.5 Air slide/commercial hauler

pg 29

4 Air compressors

pg 30

4.1 Reciprocating compressors

pg 30

4.2 Rotary axial compressors

pg 32

4.3 Vane-type compressors (blowers)

pg 33

4.4 Compressor package

pg 34

4.4.1 Compressor

pg 34

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ABLE OF CONTENTS

4.4.3 Power unit

pg 34

4.4.4 Air receiver tank

pg 34

4.4.5 Safety relief valve (PRV)

pg 34

4.4.6 Pressure gauge

pg 35

4.4.7 After cooler and dryers

pg 35

4.4.8 Unloader lines

pg 35

4.5 Air compressor moisture control

pg 36

4.5.1 After-coolers

pg 36

4.5.2 Water separator

pg 36

4.5.3 Air dryers

pg 37

4.5.4 Refrigeration

pg 37

4.5.5 Absorption

pg 37

5 Dust collectors

pg 38

5.1 Dust collector operation

pg 39

5.1.1 Cloth sock filters

pg 39

5.1.2 Pleated paper cartridges

pg 39

5.1.3 Overpressure protection

pg 40

6 Bulk system piping

pg 41

7 Pressure-vacuum systems

pg 43

7.1 Principle of operation

pg 43

7.2 Non-pressure bulk tanks

pg 44

7.2.1 Vent line

pg 44

7.2.2 Vacuum breaker

pg 44

7.2.3 Pressure relief valve

pg 44

7.2. 7.2.4 Pressure vacuum compressors

pg 45

7.3 Weigh batch blender

pg 46

7.4 Additive hopper

pg 47

8.0 Bulk equipment operations

pg 49

8.1 Operating bulk plant equipment on location

pg 49

8.1.1 STEM 1

pg 49

8.1.2 Rigging up

pg 49

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ABLE OF CONTENTS

8.1.4 Operating bulk equipment during the job

pg 51

8.1.5 Rigging down

pg 57

8.1.6 At the District

pg 57

9 Maintenance of bulk equipment

pg 58

9.1 Butterfly valve

pg 59

9.2 Check valves

pg 60

9.3 Ball valves

pg 61

9.4 Aeration devices

pg 62

9.4.1 Pipe jets

pg 62

9.4.2 Canvas pads

pg 62

9.4.3 Stainless steel pads

pg 62

9.5 Dust collector socks

pg 63

9.6 Connections

pg 63

9.6.1 Figure 206 unions

pg 63

9.6.2 Victaulic connections (groove lock)

pg 63

9.6.3 Dresser sleeve

pg 63

9.7 Safety relief valve

pg 65

9.8 Pressure gauges

pg 66

9.9 Weight measuring devices

pg 67

9.10 Annual pressure tank inspection

pg 68

10 Glossary

pg 69

11 References

pg 70

12 Check your understanding

pg 71

13 Answer key

pg 74

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I

NTRODUCTION

1.0.0

• describe bulk equipment maintenance and troubleshooting procedures.

Safety Warnings

Proper supervision is required during hands-on training. Request assistance from your supervisor if you are unfamiliar or uncomfortable with the operation.

All personnel who will be involved with bulk equipment must understand the dangers

involved with dealing with pressurized tanks. All WS and OFS safety standards must be met. Follow proper procedures before and while working with equipment (JSA, HARC, etc.). It is recommended that all personnel operating bulk plant systems and components should watch the safety video Don’t Tease the Tiger. Use the following guidelines:

• When any bulk tank is under pressure, never permit anyone to be on or under the tank for any reason whatsoever.

• Under no circumstance may any piping, connections, or unions be connected, disconnected or worked on while the vessel is under pressure.

• Never hammer on pressure vessels. • Always monitor pressure gauges.

• Never look into the end of a plugged line. This module introduces bulk operations.

Advanced bulk operations and maintenance of individual equipment pieces are included in the Advanced Bulk Plant JET Module.

This module discusses how a bulk system works, describes the system’s major components, reviews the system’s proper operation, and addresses important

maintenance issues. In addition, this module also covers the operation of a pneumatic system used in a bulk delivery system.

Schlumberger uses bulk systems to store and blend bulk materials used in cementing and fracturing. The system is also used to supply bulk material such as cement and barite to mixing equipment. The success of a job is directly dependent on the proper blending and delivery of materials, which is controlled by proper operation of the bulk equipment.

Learning objectives

Upon completion of this module, you will be able to:

• explain the principle of pneumatic conveyance in both full pressure and vacuum plants

• identify the differences among various types of bulk storage tanks, air compressors, vacuum pumps, dust collectors, piping, and pressure-vacuum systems

• describe the operational guidelines for district bulk plants and bulk plant equipment on location

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P

RINCIPLES

OF OPERATION

2.0.0

Air bulk transport (ABT)

Adds Cement and pozzolans Blend Additive/ cutting bottle Weigh batch blender (WBB) Holding tanks Pressure tanks Compressor Dust collector Air Air compressor Bulk system

JET 6 – Bulk System Training Manual v1.0

2.1 Purpose of a bulk system

There are many ways to move large quantities of powdered or granular solid materials such as sand, barite, or cement, including augers, conveyor belts and hand-carried sacks. The preferred method at Schlumberger is pneumatic transport.

Pneumatic (operated by air) transport is a system that uses compressed air to fluidize the dry material and carry it from one place to another within a bulk system. A bulk system as defined here includes all associated equipment used to store, blend, and transport bulk

material.

A pneumatic and vacuum bulk system is the preferred way to move cement and other materials like sand, bentonite, pozzolan, and barite for the following reasons:

• high transfer rates

• low manpower requirements • less material lost or damaged • environmentally cleaner

In the vacuum plant the storage tanks are non-pressurized vessels. The only pressure tanks are the WBB, holding tank, and mix tanks. All vacuum storage tanks require a full open vent and a 2-in vacuum breaker. These components should both be placed on top of the tank system.

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BASIC BULK SYSTEM COMPONENTS

2.2.0

Air bulk transport (ABT)

Adds Cement and pozzolans Blend Additive/ cutting bottle Weigh batch blender (WBB) Holding tanks Pressure tanks Compressor Dust collector Air

Bulk system components

Schlumberger uses pneumatic bulk equipment to store, blend, transport and deliver bulk materials to mixing equipment. A basic pressure bulk system is made up of the following components:

• air compressors (two: one high-pressure for bulk plant controls, and one high-volume for bulk)

• vacuum pumps in pressure/vacuum systems

• bulk tank also called a pressure tank or P-tank in pressurized bulk plants; storage tanks are non-pressurized in the pressure/ vacuum system

• piping for air supply, bulk loading, bulk discharge, and venting

• a dust control device (either sock or filter) • measuring and sampling devices (load

cells, gauges, cement samplers, etc.) New plants involve the use of:

• WBB (weigh batch blender) • double-stacked tank

• truck mix tank

The WBB and the truck mix tank each have measuring devices to ensure total product delivery and service quality to the customer.

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PRINCIPLES OF PNEUMATIC CONVEYING

2.3.0

Properties of particle materials

MATERIAL SIZE SPECIFICGRAVITY ILUMINITE D18 4.45 SILICA SAND D30 SILICA FLOUR D66 FLY ASH D35 2.65 2.65 2.48 3.16 CEMENT

Piping _{Bulk tank}

• the amount of air and the size and weight of the particles of material

As compressed air flows through bulk material, it tends to “fluff” or aerate the particles. Once aerated, the particles are carried by the air as it moves to a lower pressure area.

The amount of material carried by the air depends on many factors, including:

• the size of the piping between the tanks, and the cleanliness of the piping (dirty lines reduce the pipe ID)

• the length of piping between the tanks, as well as elbows and restrictions

Dilute Phase 1

Few particles of the bulk material are being carried; the air velocity is high.

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Surge can

• the pressure of the receiving tank (e.g., surge can).

Ways in which air carries bulk material are shown in the examples that follow.

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Air velocity high

Air velocity high

Lower air velocity

Lower air velocity

High air velocity

Lower air velocity

Unsteady Conveying

JET 6 – Bulk System Training Manual v1.0 ₁₀

Dilute Phase 2

Few particles of the bulk material are being carried; the air velocity is lower than in Dilute Phase 1.

Unsteady Conveying 1

Few particles of the bulk material are being carried; the air velocity is high above a dune and lower in clear part of the line.

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Air velocity < Unsteady conveying 1 air velocity

Unsteady Dense Plug Flow

Air velocity < Dense plug flow air velocity

Steady Dense Flow

JET 6 – Bulk System Training Manual v1.0 ₁₁

A large amount of the bulk material is being carried; the air velocity is lower than Unsteady Conveying 1. The air-bulk material ratio is not constant throughout the line.

Steady Dense Flow

A large amount of the bulk material is being carried; the air velocity is lower than Dense Plug Flow. The air-bulk material ratio is constant throughout the line.

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JET 6 – Bulk System Training Manual v1.0 ₁

Note:

A more complete discussion of the different types of flow regimes for bulk materials in pneumatic transport can be found in the Cementing Materials Handling Manual, InTouch content ID# 3845898.

Steady Dense Flow

The bulk-to-air ratio is constant throughout the transport line.

This type of flow appears as a steady stream of bulk material. The cement delivery rate can be controlled at the discharge end of the transport line. There must be enough pressure at the bulk tank to overcome all pressure drops in the transport line. To have this type of flow, the theoretical pressure drop required is 1.6 psi for each foot of transport line.

An example of this type of flow is a MARK III mixer hooked up directly to a bulk trailer with a short (<20-ft or <6.1-m) bulk hose.

The type of equipment used by Schlumberger generally causes the transport to be Steady Dense Flow if the length of flow is 20 feet or less, and Unsteady Plug Flow if the length is over 20 feet. The aeration system must be operating properly to use this rule.

Guidelines for operating Schlumberger bulk equipment for both types of flow can be found in Section 8, Bulk equipment operations.

Schlumberger operates bulk systems using the last two types of flow - Unsteady Dense Plug Flow and Steady Dense Flow.

Unsteady Dense Plug Flow

The bulk-to-air ratio is constant in short sections of the transport line, and there are sections of air between these bulk-air slugs.

This type of flow appears as slugs of dense bulk followed by a blast of air. The delivery rate is controlled at the bulk tank located at the beginning of the transport line. Air may have to be added to the system after the cement leaves the tank. The pressure drop required for this type of flow is less than that required for Steady Dense Flow.

An example of this flow is a bulk plant on an offshore rig hooked up to a surge can through a long (>20-ft or > 6.1-m) length of piping.

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PRINCIPLES OF VACUUM CONVEYING

2.3.0

Vacuum conveying consists of the following process:

• All products stored in non-pressure storage tanks are protected by both a full open vent system and a vacuum breaker (these containers cost less than pressure tanks). • Products to be blended on transfers are

moved to the WBB by means of vacuum (differential pressure created between the

atmospheric and the vacuum pump). • The WBB is then pressurized for both

blending and transfer through the double stack tank and then to the truck mix tank and on to the bulk transport.

• Additives are also moved to the WBB through an additive cone by vacuum.

The pressure vacuum plant has the following advantages:

• All storage tanks are non-pressured and considerably less costly.

• When filters are properly maintained, the plant is more environmentally friendly. • Additives are added by means of a cone

and vacuum and do not require an additive tank or another pressure vessel.

• Product transfer takes place at a higher rate, reducing blend and load time.

The components involved are a high-volume air compressor, a high-pressure air compressor (for controls), a high-volume vacuum pump, and a quality air dryer.

This process and the components involved are discussed in depth in Section 7.0, Pressure-Vacuum Systems.

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B

ULK SYSTEMS

3.0.0

Bulk storage tank

This section describes the major components used in Schlumberger pressure and vacuum bulk systems and explains their principles of operation.

3.1 Bulk storage tanks

A bulk tank is both a storage tank and bulk feeder, supplying bulk materials to other parts of the bulk system or discharging them to a mixing system. This process occurs by way of either pressure or vacuum, depending on which type of plant is in place at the district. Schlumberger uses two types of bulk storage tanks:

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ABT truck

Surge can

Names of pressurized tanks:

Bulk tanks Bulk trucks

Pressurized silos Pressurized tanks P-tanks silo

P-cans ABT(Air bulk truck) Banana bulk truck Field bin

Names of non-pressured tanks Gravity bins Surge cans Air slide Commercial hauler Gravity cans Surge tanks Storage tanks District storage

Non-pressurized tanks

These tanks do not meet the requirements of pressure vessels, and have a maximum allowable pressure of 1 bar or 15 psi. They may also be zero pressure containers with a 5-psi pressure relief valve, a vacuum breaker and a fuel open vent system on top of the

tanks. Pressure limits must be clearly marked on each type of vessel, and necessary

pressure relief valves must be installed. Some of the many names for tanks used as bulk storage tanks are listed below.

Pressurized tanks are sometimes referred to by their size, e.g.,“1,050s” for 1,050 ft3 or “850s” for 850 ft3 tanks. One of the more common is a 1,030 (1,030 ft3).

Non-pressurized tanks are also known by several names, including the following:

Pressurized tanks

These tanks are pressure vessels that meet strict requirements. Most countries consider 1 bar or 15 psi the critical pressure that designates a tank as a pressure vessel.

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PRESSURE TANK

3.2.0

Vent line Fill line

Pressure relief valve Pressure gauge

Discharge line Air supply line

Manway

Pressure tank Fill line and discharge line

1

3.2.1 Components of pressure tank

This section describes the functions of the pressure tank components.

3.2.1.1 Fill line

The fill line is used to convey bulk material from an outside supply to the inside of the tank. The fill line is fabricated so the end of the line extends into the interior of the tank at its top such that the bulk material falls down into the tank as it is filled, and bulk material does not cover up the entrance into the tank. Care must be taken not to overfill the tank when supply is being delivered, as this may contaminate other products or spill into the vent system.

3.2.1.2 Discharge line

Bulk material is discharged from the tank into another tank or mixing system through the discharge line. The discharge line originates inside the bulk tank at the bottom, penetrates the tank wall to a discharge point outside the tank (see Pressure tank illustration, above left). Some tanks are constructed with the discharge line starting as a hole in the middle on the bottom of the tank, while other tanks have the discharge line starting as a dip pipe reaching down to the middle of the bottom of the tank. A valve is installed on the discharge line near where the line exits the tank.

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Pressure relief valve

Pressure relief valve close-up Vent line

3.2.1.3 Vent line

The vent line allows the venting of air and pressure from inside the tank to the outside. This is necessary when transferring bulk materials into the tank (so that the air helping to convey the material exits the system), or when bleeding pressure from the tank. The vent line is designed to start from the inside of the top of the tank to a point towards the bottom of the tank.The vent line can indicate when the tank is full if bulk material flows to the dust collector. Extreme care should be taken to prevent material from entering the dust collector. A valve is installed in the vent line so that pressure can be put on the tank when it is closed.

Note:

Vent line valves should be removed from tanks used in vacuum systems to prevent the tanks from collapsing.

3.2.1.4 Pressure relief valve

The fill line and vent lines are similar to each other, but the vent line is identifiable by its pressure relief valve (commonly called a pop-off valve) and pressure gauge.

The pressure relief valve can also be mounted on the shell of the tank and is designed to relieve tank pressure if it exceeds a preset pressure. Most of the pressurized bulk tanks used by Schlumberger are designed to operate at 30 psi, and the pressure relief valve is designed to open at 35 psi. Refer to Maintenance Bulletin 625E, InTouch content ID# 3998770.

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Pressure vessel location

Inland barges

Land bulk storage tanks Offshore tanks

ASME coded tank allowable

working pressure valve setting (psi)

Offshore tanks

Land bulk storage tanks

Truck bulk tanks Portable field bins Air slide transports P-tanks

P-tanks

Air slide transports

Pressurized surge cans

30 30 35 30 30 15 30 5 35 35 35 35 35 18+15 psi regulator 35 10 Pressure relief

Some tanks are also equipped with a rupture disc. This is an additional safety device designed to shear if the pressure rises above the designed limit. When the disc ruptures, all pressure is lost from the tank and the disc must be replaced before the tank can be used again.

Schlumberger uses many pressurized tanks. This list of tanks and their pressure relief valve settings is taken from Maintenance Bulletin 625E, InTouch content ID# 3998770.

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Pressure gauge

Vent line Fill line

Pressure relief valve Pressure gauge

Manway

Air supply line

3.2.1.5 Pressure gauge

For safety reasons and tank operation, every bulk tank must have a working pressure gauge. The gauge should be installed on the vent in a position that will minimize the amount of dust to which the gauge inlet is exposed during operation. It is important that the gauge is checked and inspected regularly during any operation.

Note:

It is critical to Schlumberger that all safety devices be kept in operating condition at all times for both safety and legal reasons.

3.2.1.6 Air supply line

This line supplies the compressed air used to carry bulk material out of the tank. This line could be mounted anywhere on the outside of the tank, but it is connected to the aeration device on the inside of the tank. A valve is installed on the air supply line to control the amount of air entering the tank. The air supply line will normally have a check valve to prevent bulk material from plugging the air system if the aeration device fails.

Some tanks are equipped with a small valve on the vent line to slowly bleed off the pressure in the tank. This valve should not be used to pressurize the tank; all air used to pressurize the tank should go through the aeration devices.

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Pipe-jet

Offshore silo pads

Land based pads

Pads

JET 6 – Bulk System Training Manual v1.0 ₀

Note:

Most tanks equipped with a pad-type aeration device have an equalization valve that keeps the pressure the same on both the top and bottom of the pad. If the pressure is not equalized, the pad can rupture.

3.2.1.7 Aeration device

Schlumberger uses two types of aeration devices that enable compressed air to fluff/ aerate through the cement. These devices fluidize as much of the contents of the tank as possible. The aeration device fluidizes bulk material in the bottom of the tank so that it can begin to flow out of the discharge.

3.2.1.8 Pipe jets

These are installed in the bottom of the tank and direct air flow into the tank. The jets are covered with a membrane to prevent them from being filled with bulk material. A check valve is also required on the inlet side (outside the tank) to prevent backflow of dry material into the air system.

3.2.1.9 Pads

Pads installed in the bottom of the tank are made of a porous material that allows air flow into the tank. The pads, which are commonly made of canvas, are designed to a allow air to flow into the tank but prevent cement from flowing into the air system piping.

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From storage tanks

WBB Double-stacked tanks Mix truck tank

Transport

Manway

Transfer of blend in vacuum system

This process is the same in both full-pressure and pressure/vacuum plants, with the

exception that products and additives enter the WBB under pressure and by way of a vacuum in a pressure vacuum tank.

3.2.2 Weigh batch blender (WBB)

A weigh batch blender (WBB), shown below, is a specialized pressure vessel used to weigh and blend bulk material. A WBB has steep sides in its cone area and jets as its aeration device.

Our service quality standard specifies a minimum of three movements of the bulk blend to ensure a proper blend. This requires the addition of the double stack and a truck mix tank. These additions make a total of five movements:

1) WBB

2) top of the double stack 3) bottom of the double stack 4) to the mix tank

5) on to the transport.

3.2.1.10 Manway

Each tank is equipped with a manway that allows inspection of the inside of the tank. The manway can be located on the top, bottom or side of the tank.

If the manway is located on the top of the tank, a ladder should be permanently mounted on the outside and inside of the tank. If the tank is over 12 feet tall, the outside ladder must have a cage.

Note:

Always comply with relevant safety standards for working at heights, manways, vessel entry, and when lockout/tagout is applicable.

Note:

Never modify a tank that is a ASME code vessel. Any modifications to an ASME tank must be made by a company certified to do such work.

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Additive/Cutting bottle Weigh batch blender

Vacuum/pressure tanks

In a pressure/vacuum plant, the additive bottle is replaced by an additive cone operating under vacuum. Additives are dumped into the hopper and the rate of flow is controlled by a butterfly valve.

3.2.4 Bulk tank construction

All of the pressure bulk tanks used by Schlumberger are designed and built to the standards of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, Sections I, VIII and IX. These standards govern the type of metal, the welding procedures, and testing procedures used during manufacture. In addition, the code requires personnel involved in the In the pressure vacuum plant the WBB is

both a pressure and a vacuum vessel, and is protected with a PRV and a vacuum breaker. Most WBBs are built with three legs. Two are attached to the base with pins or ball-joints so the third leg is free to move. The third leg is held up by a load cell which transmits a hydraulic or electronic pressure signal to a weight scale. Strain gauges attached directly to the legs can be used instead of the load cell, but they are more costly to install.

3.2.3 Additive/Cutting bottle

Full pressure plant

An additive bottle is a small pressure tank that adds sacked material to the WBB, and is used in full pressure plants. Cutting bottles also used to cut and load sacks and/or big bags of material such as cement or sand when these are not delivered in bulk.

The additive bottle, which can be either of the designs shown here, does not have a fill line; material is added either through a hatch or a valve built into the top of the tank.

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Identification plate

Bulk tank

An ASME code inspector must approve the work to be done and must inspect the work after it is completed. The inspector prepares a report (the partial data sheet), which indicates his approval of the repairs. The report must be kept on file for the life of the tank. If repairs are needed, approval must be obtained from the local maintenance department before beginning any repair.

Note:

Pressure bulk tanks that meet all requirements of the ASME code are called Coded Tanks, and bulk tanks designed for pressures less than 15 psi are referred to as Non-Coded Tanks. welding and inspection to be ASME-approved. The ASME code is the accepted standard in most countries.

To construct a tank that qualifies as an ASME tank, the manufacturer must have a current certification called a “U” stamp. To make repairs or modify an existing tank, the shop doing the work must have a current certification called an “R” stamp.

Each ASME-coded tank has an identification plate similar to the one shown below, with the working and test pressures of the tank stamped on the plate. Information on this plate is

required for the tank to pass safety certification inspections, and the plate must remain on the tank throughout its life.

Note:

Any repairs to the tank itself that require welding or cutting must be done by an ASME-coded shop using a coded welder.

The records of these containers are registered with the National Board with a serial number; should a plate become unreadable, the district records can be sent to the original manufacturer to produce a new plate.

The plate must be protected throughout the life of the tank; therefore, measures must be taken to protect these plates during the process of repainting, sand blasting, etc.

Only pre-approved suppliers are allowed to manufacture bulk tanks for Schlumberger.

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JET 6 – Bulk System Training Manual v1.0 JET 6 – Bulk System Training Manual – October 2005 v1.0 

Discharge valve Aeration device jets Weight indicator

Fill line

GRAVITY DISCHARGE BULK TANKS

3.3.0

Surge can

As the name indicates, gravity supplies the energy to empty gravity silos and surge cans. Air is used to keep the bulk material fluffed up and to prevent it from bridging off inside the tank. Because this tank uses gravity to empty, it is used only to deliver bulk material to a mixing unit. The design of gravity silos and surge cans is similar, the biggest difference being their size. A gravity silo is usually 550 ft3_{(15.7 m}3_{), while a surge can is usually 70 ft}3 _{(1.98 m}3_).

A surge can performs three functions:

• Separates the bulk material transport system from the bulk material supply system prior to mixing. This is important for the Unsteady Plug State. This type of flow occurs if the Schlumberger mixing unit is more than 20 feet away from the bulk tank.

• Allows air used to transport the bulk material to escape. This is important for the Unsteady Plug State due to the large amounts of air that are required for the distance the bulk material is being conveyed.

• Provides a buffer when switching from one P-tank to another.

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Discharge valve Aeration device jets Weight indicator

Fill line

ojo

3.3.2 Air supply line

This line supplies air to fluff up the bulk material. The air flow maintains a consistent flow of bulk material and prevents the line from bridging off inside the tank.

3.3.3 Aeration device

The aeration device enables the compressed air vent to aerate through the bulk material. This device is designed to fluidize as much of the contents of tank as possible and, as with pressure tanks, Schlumberger uses two types of aeration devices (pads or jets).

Surge can components

Aeration device: jet

A gravity silo can perform all the functions of a surge tank and is large enough to be used as a storage tank for bulk material systems on location.

Most of the components of gravity discharge tanks perform the same function as a pressure tank; however, a few of the tank components have different functions, as described below:

• The pressure relief valves (pop-offs) on surge cans and gravity cans perform the same function as those found on pressurized tanks, limiting the maximum pressure inside the tank

• The pressure relief valves on surge cans and gravity silos are set to much lower pressures than the relief valves on pressurized tanks. Gravity silos should be equipped with safety relief valves set at 3 psi, and the pressure relief valves on

surge cans should be set at 10 psi. Some tanks are equipped with rupture discs instead of, or in addition to, pressure relief valves.

3.3.1 Discharge valve

This valve controls the rate at which the bulk material (usually cement) falls from a gravity silo or surge can. The valve is relatively large, usually 8 in (20 cm) or larger, so that high discharge rates can be achieved.

The valve is normally a butterfly valve. It is important that the valve is well maintained and in good working condition, and that the surrounding area inside the silo is clean and free of cement after every job.

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Sight glass

Sight glass Sight glass

Load cell

Surge can and load cell

3.3.4 Sight glass

Surge cans are fitted with small windows to allow visual monitoring of cement inside the tank.

3.3.5 Weight indicator

Surge cans can be fitted with weight indicators so the level of bulk material inside the tank can be measured. The load cell/indicator system used on surge cans works in the same way as systems found on most WBBs. The load cell and weight indicator have to be calibrated to take into account the weight of the tank so that the read-out gives bulk material weight only.

A hydraulic load cell holds up one side of the surge can, while the other side of the surge can is connected to the frame with pins that allow the surge can to pivot. The force from the tank is exerted on the surface of a diaphragm in the load cell.

The weight of the load cell forces the fluid to the weight indicator gauge, which reads in weight not pressure. The gauge is matched to the load cell for calibration purposes. Field replacement of either the gauge or the load cell must be an exact match for proper weight indication.

Note:

Gravity silos and surge cans (”non-code tanks”) are not built to the rigid standards required for tanks that will have more than 15 psi of pressure. Nonetheless, these tanks must be treated with the same respect as pressurized tanks. The amount of force contained within these tanks is tremendous, and the film Don’t Tease the Tiger shows dramatically the power of very low pressures exerted on large surfaces.

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Surge can

Vent line

JET 6 – Bulk System Training Manual v1.0 JET 6 – Bulk System Training Manual – October 2005 v1.0 

Schlumberger also uses a special-designed surge can called a pressurized surge can. This tank is a pressure vessel much like the pressurized tanks described earlier, but it does not meet the strict standards of ASME code for a pressure vessel and its pressure is limited to 15 psi just like a standard surge can. This surge can is typically used in conjunction with the Slurry Chief mixer on offshore skid units. The special features of a pressurized surge can are described below.

3.4.1 Vent line

The vent line is equipped with valves; a vent control valve and a vent bypass valve. If the bypass valve is left open, the surge can performs as a standard surge can. The vent control valve is automatically opened and closed to maintain a set pressure inside the surge can, usually 5 to 7 psi.

3.4.2 Pressure sensor

A pressure transducer is mounted on top of the surge can. This transducer sends a pneumatic pressure signal to the controller.

PRESSURIZED SURGE CAN

3.4.0

Fill line Vent line Vent control

valve

Air supply line Weight indicator Load cell Jets Discharge valve Surge can Pressure sensor Pressure relief valve

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3.4.3 Pneumatic controller

A pneumatic controller controls the opening and closing of the vent control valve. The controller maintains pressure in the surge can at a preset point.

3.4.4 Side discharge

In addition to the discharge valve in the bottom of the surge can, the pressurized surge can is equipped with a side discharge. The small amount of pressure kept in the surge can enables bulk material to be discharged a short distance through this side discharge.

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AIR SLIDE/COMMERCIAL HAULER

3.5.0

Trucks that transport bulk material are not certified pressure vessels, and are often

referred to as air slide and commercial haulers. The differences between these trucks and other pressure bulk tanks and trucks are the working pressure limit and the type of aeration system.

Unlike a pressurized tank, which operates at pressures up to 30 psi, air slides and commercial haulers have non-coded tanks that operate under 15 psi. These tanks have a pressure regulator set for 15 psi and a pressure relief valve set for 18 psi. Maintenance Bulletin 743A MUST-DO, InTouch content ID #4128998, describes these safety devices.

Note:

This type of bulk truck delivers cement at rates of 1,000 to 2,000 lbm/min, which is about half of what is expected from a pressure-type coded bulk tank.

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A

IR COMPRESSORS

4.0.0

Compressor

Intake stroke

Compression stroke

Compression stroke

The air in the cylinder is compressed as the piston travels up. The intake valve closes and the exhaust valve opens as the air pressure inside the cylinder exceeds the pressure in the discharge piping.

The basic principles of operation of a single-stage reciprocating compressor are much like those of a two-cycle engine.

Intake stroke

The air passes through a filter to ensure that only clean air reaches the cylinder. Air enters the cylinder through the intake valve, which is opened by the difference in pressure and is drawn into the compressor’s cylinder as the piston travels down.

Air compressors provide all of the energy needed to run a bulk system. Schlumberger uses several different types of air compressors, most of which are designed to operate at 30 to 32 psi and deliver 300 to 400 ft3_{/min of air, or}

29 in of mercury at 425 ft3_/min.

4.1 Reciprocating compressor

Single-stage-reciprocating compressor are commonly used in Schlumberger.

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Unloader assembly Cylinder assembly

Unloader pilot valve

Unloader Intake stroke

How pressure is controlled

Regulator or unloader type system

The discharge pressure of the air compressor is regulated to stay within preset limits. The unloader valve senses system pressure versus the desired preset pressure. When the desired system pressure is achieved, the unloader valve sends air pressure to the pilot unloader; the plunger holds the intake valve open, thus allowing the compressor to keep cool and preventing the compression process. The differential pressure of the unloader should be set within 15 percent of the set pressure. If the differential pressure is greater than 15 percent it indicates an unloader system malfunction that requires service and calibration.

The diagram below illustrates a typical unloader on reciprocating compressors.

Another type of system utilizes a pressure switch to allow the electrical motor to turn on and off as needed to maintain a set pressure. This is the most common type of regulator for small compressors that must furnish high pressure (125 to 150 psi), for example in maintenance shops. The pressure switch senses tank or system pressure; when the system reaches the set pressure, the pressure switch turns off the electrical motor turning the compressor. This system is primarily used in the bulk plant for controls such as high-pressure valve actuation.

A valve in the switch opens to bleed pressure off the cylinder so that when the compressor restarts it is not starting under load. The switch has a differential spring setting, which should be set at 20 percent of system pressure, to turn the motor back on when necessary. It gives no warning prior to starting, so it must display a sign as described in the Well Services

Safety Standard 04: Facilities and Workshops, InTouch content ID# 3313678.

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ROTARY AXIAL COMPRESSOR

4.2.0

Rotary axial compressor

Rotary axial flow compressor, commonly known as a screw compressor, is capable of producing high volumes of air (100 to 1000 ft3_{/min at 100 to 175 psi).}

Air is pulled into the compressor housing by the rotation of the screw-type rotors, and is trapped between the lobes of each rotor and the housing wall.

As the screws rotate, the air is compressed and moves toward the discharge end of the rotors. The rotors are tapered to a smaller diameter on the discharge end, which creates a smaller chamber for the air, compressing it before it is discharged.

Constant speed control regulation allows the compressor to be unloaded at a set pressure while the electric motor continues to operate at a fixed RPM. The basic principle of constant speed regulation is to throttle an intake

valve open or close, and regulate the ft3_/min

discharge, thereby regulating the psi.

Some screw compressors are driven by diesel engines. When the discharge pressure is at or above a set pressure, a variable speed regulator closes off a valve in the intake of the compressor to restrict air to the compressor to regulate discharge volume or ft3_/min.

Simultaneously, it throttles the engine to idle position. When it senses a 15 percent drop in the pressure, it throttles the engine back to fast idle RPM and then opens the valve to the intake.

This type of system reduces the need for

large-volume storage tanks, but requires a larger than average compressor for ft3_/min

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VANE-TYPE COMPRESSORS (BLOWERS)

4.3.0

Blower

relies on a constant speed control regulator, as described below. It is critical that air is constantly passing through the blower.

1. Air from the receiver acts on the unloader pilot valve. If the pressure is above the set pressure (usually 32 psi), the pilot valve opens, allowing air to flow to the 4-way unloader valve.

2. The 4-way valve directs high-pressure air to open the control valve, allowing excess air to be discharged to the atmosphere. This allows the compressor to keep running unloaded.

3. The unloader valve piston will close as the pressure falls below a set point (usually 28 psi). This causes the 4-way valve to

shift, closing the control valve.

4. Compressed air is again supplied to the system.

Pressure regulator

Vane type compressors, also called blowers, are designed to deliver 150 to 400 ft3_{/min at}

pressures up to 35 psi.

As the power source turns the rotor, centrifugal force pushes the vanes outward, sealing the vanes to the housing. Air is pulled into the area between the vanes and housing, trapping the air. As the vanes travel along the cam, the volume between the rotor and the cam gets smaller, which compresses the air. The cam is designed so that the maximum volume between vanes is at the air intake, and the minimum volume between vanes is at the discharge.

A valve on the discharge flow stream is the most commonly used control system on a blower-type compressor. When the preset system pressure is reached, an air actuator opens the valve and the compressor discharges to the atmosphere until the valve closes again. A check valve contains the pressure downstream of the tee.

Pressure regulation for blowers

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COMPRESSOR PACKAGE

4.4.0

A typical compressor package used by

Schlumberger includes many components, as described below:

4.4.1 High-volume compressor and

high-pressure (controls) compressor

The compressor usually has two or three cylinders, and is capable of delivering 300 to 400 ft3_{/min at 30 to 40 psi; or it can be a rotary}

screw such as the Palatek unit, which can be used on both a pressure or a vacuum pump.

4.4.2 Air filters

Each compressor usually has one air filter per cylinder. It is common to see 3-cylinder compressors with two, or even one, air filter as long as the total ft3_{/min capabilities of the}

air filters meet or exceed the needs of the compressor. It is important to keep air cleaners clean.

Vacuum pumps require their own filter or the use of the dust collector filter on top of the WBB in the vacuum mode.

Compressor components

Diesel engine Air filter

Compressor

Air reciever tank

On a reciprocating compressor, if the

differential pressure of the filter is too high, it will cause a vacuum between the air cleaner and the cylinder. This usually results in a vacuum that pulls oil up through the piston rings and discharges it into the pressurized air. This oil can be carried all the way to the pads in the bulk cement tanks. Because dirt is very abrasive, dirty air filters can cause serious damage to the compressor.

Dirty air filters on a vane-type blower can cause the vanes to disintegrate.

4.4.3 Power unit

A 70 HP diesel engine, an electric motor or the engine of a tractor truck drives the compressor.

4.4.4 Air receiver tank

This tank stores a small volume of air that can satisfy an increase of the ft3_{/min output}

needed from the compressor, such as blowing lines clean. The tank can also act as a water trap if the air velocity in the tank is lowered sufficiently to allow water droplets to fall out of the compressed air. The air receiver tank also helps the length of the cycle time between the time when the compressor unloads and when it reloads. This is most often an ASME container.

4.4.5 Safety relief valve (PRV)

This valve is set to open if the pressure of the compressor exceeds a set limit. All PRVs should be tested periodically.

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4.4.8 Unloader lines

The pressure regulation system of the compressor uses these lines to transmit the system’s operating pressure to the compressor. Water in the compressed air system can

damage the bulk material, make the bulk material more difficult to move and cause blockage of the aeration devices (pads and jets). The principle methods used to control moisture in air systems are described below. Water may also freeze in low temperatures and prevent proper valve operation.

Unloader line

The three measures of pressure control in this process are in this order:

1) cycle-through pressure regulation 2) PRV pressure relief valve

3) rupture disc.

4.4.6 Pressure gauge

This gauge allows the operator to check the operation of the compressor. The location of pressure gauges in the system helps the operator identify potential problems or restrictions in the system. This may also be a lube oil pressure gauge.

4.4.7 After-cooler and dryers

After-coolers remove the heat that air acquires during compression. The cooling of the air also removes moisture, which is drained off.

Dryers, on the other hand, do nothing to cool the air, but have passive desiccant cartridges that remove the moisture from the air. The moisture is channeled to the bottom of the dryer where it is purged from the system by a signal from the unloader. A typical air dryer operating with a 235-CFM screw compressor at 100 percent humidity can discharge 100 gal of water in a 24-hour period. Desiccant dryers require periodic servicing.

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AIR COMPRESSOR MOISTURE CONTROL

4.5.0

Water separator

4.5.2 Water separator

A simple way to separate water from air is to slow down the air and allow water droplets to settle out and be drained off. A large receiving tank works this way. The tank also tends to radiate the heat of the air and this cooling causes water in the air to condense.

To help separate moisture, air receivers or volume tanks should always be plumbed so that the discharge of the air compressor comes into the tank lower than the air outlet. In areas of high humidity, large volume tanks are needed to capture the moisture to prevent damage to air controls.

Smaller inline water separators, such as those used on air controls, use a centrifuge method in which air is swirled around the bowl to make the water fall out. These separators work best in low-volume applications.

4.5.1 After-coolers

After-coolers cool the hot compressed air discharged by the compressor to remove moisture.

Air heats up as it is compressed, and heated air is able to hold more water as a vapor. Cooling the air causes the water vapor to condense, and the condensate can be drained out of the system. A water-to-air or air-to-air after-cooler is a device fitted directly to the compressor discharge that is designed to cool the air and cause water vapor to condense.

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Air dryer

4.5.4 Refrigeration

Compressed air is cooled to near freezing, and most of the water content in the air condenses then the air is reheated.

4.5.5 Absorption

A chemical absorbs water from the

compressed air, then turns into a liquid and is drained away. The chemical is not reusable. Refrigerant dryers are not usually found on the compressors that Schlumberger uses for bulk systems. Schlumberger uses after-coolers and air receiver tanks to control the water content of compressed air. Most of the new or upgraded plants in North America use refrigeration-type dryers.

4.5.3 Air dryers

Devices used to dry the air are more

complicated than the after-cooler and the water separator discussed previously. Air dryers use either the refrigeration or the absorption method, described below, to lower the amount of water in the air system.

Note:

Lubricators are necessary for the proper operation of air control. Air first travels through the air dryer or water separator to clean the air, then the lubricator adds oil to the air for the components.

Lubrication must be adjusted to the proper flow. Too much oil in the system can be messy and cause problems with some components, while too little lubrication will result in some components not getting any lubrication. A good rule of thumb is 4-6 drops per minute using SAE10 oil or engine oil cut with diesel 50/50. Do not use Marvel Mystery Oil because it creates a film that causes components to stick or hang up. Make certain the air supply is bled off when filling the lubricator.

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D

UST COLLECTORS

5.0.0

Vibrator assembly Air outlet

Air inlet

To the collection tank

Dust collector

Interior of dust collector

Inlet line of dust collector

An inlet line is to be hooked to the vent line of the bulk tank being loaded.

Outlet line of dust collector

The outlet line is a large opening that allows clean air to exit the dust collection system.

Filter

The filter, such as a sock or cartridge prevents dust from exiting the dust collector.

Dust collector bags are used on locations where the bulk equipment is not equipped with a permanent dust collection system.

Every bulk system must have some sort of dust control system, which must be designed to meet local air quality regulations.

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D

UST COLLECTOR OPERATION

5.1.0

Vibrator assembly Air outlet

Air inlet

To the collection tank

The dust collector system is divided into two sections. The upper section contains the filters, while the lower section is open to collect and hold the dust particles in the collection tank. Dirty air enters the system just below the filter where dust is caught by the filter, allowing clean air to exit the system. The filter has to be cleaned for the system to continue to work properly.

The methods used to clean the filters are described below:

5.1.1 Cloth sock filters

Dust is filtered out onto the cloth material as airflows through. Periodically the socks are shaken off by a vibrator assembly built into the top of the collector. Continuous shaking of the socks causes dust to migrate through the sock, and some dusty air will exit the collector. The shaker should be run 15-20 seconds after each load, or 30 to 60 seconds out of each 15 minutes of operation. Each district should establish regular intervals for running the dust collector.

Dust sock filter

5.1.2 Pleated paper cartridges

Another type of filter is the pleated paper type shown in the illustration on the following page. The dust filters out onto the pleated paper as air flows through the cartridge. A jet of high-pressure air clears the dust from the filter and causes the accumulated product to fall into a collection tank below the dust collector. The frequency of the air blast can be varied, but should be set for intervals of 4 to 6 seconds. The air jet should be started before the dust collector is used and continued until after the dust collector is no longer needed.

Note:

It is normal to lose 0.5 to 3.0 percent of the material being transferred as dust. The vent system and dust collection tank must be capable of holding this amount of bulk material.

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5.1.3 overpressure protection

Dust collectors are designed with some type of overpressure protection to prevent them from shutting down the whole bulk plant. If overpressured, sock-type filters simply blow apart or blow off their mounting and allow dirty air to escape directly into the atmosphere. The pleated paper cartridge type of dust collectors are constructed with a bypass mechanism that opens if the pressure becomes too high.

These filters are also used to protect the vacuum pumps in pressure/vacuum plants by filtering the air on the inlet side of the vacuum pumps.

Dust filter

Air outlet Air inlet

Air jet assembly

High-pressure air supply regulated to 60 psi Air filter housing To the collection tank

Pleated paper cartridge

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B

ULK SYSTEM PIPING

6.0.0

Delta wye

Discharge hose Butterfly valves

The pipe used for fill lines, discharge lines and vent lines in a bulk system is usually 4-in or 5-in diameter steel. Larger pipe requires higher volumes of air to transport bulk material, while smaller pipe requires higher pressures to overcome friction losses.

To make flow through the lines as smooth as possible, long radius elbows and Delta wyes (shown below) are used instead of standard elbows and tees. This is often referred to as 3R (triple the radius), the preferred alternative being 2R (twice the radius).

Butterfly valves control the flow of materials in a bulk system. The air supply line may be equipped with either butterfly valves or ball valves.

Bulk discharge hose (usually 4-in diameter) is used to hook up to portable units and must meet Schlumberger specifications for a discharge hose. The specifications for blender discharge hose and bulk discharge hose can be found in the Treating Equipment Manual, Version B, InTouch content ID# 3013931. The hose must be double-clamped with clamps 90 degrees apart.

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Blanking caps should be designed as shown, so that the nut can be loosened and the plug moved to check for pressure without the risk of blowing the cap off. Never use one-piece wet caps on a dry bulk line because it is not possible to tell if there is pressure on it when removing the cap.

A rock catcher filters chunks of hard cement or rocks that may be present in dry bulk material when it enters or leaves a bulk plant. The rock catcher has a screen that allows bulk material to flow through, but which will catch larger particles.

Blanking caps

Rock catchers are intended, for the most part, to ensure product quality from the supplier and are installed on each individual product line from the vendor.

The new version of the rock catcher has a replaceable screen.

Rock catcher

WARNING: Discharge hoses CANNOT be used on the discharge side of triplex or other high- pressure pumps, or on the suction side of centrifugal pumps. Before using the hose, check it carefully for any signs of cracking or damage. The pressure rating of the hose is between 100 and 125 psi; therefore, if a damaged hose fails under pressure, it causes damage to equipment and injury or death to personnel.

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P

RESSURE-VACUUM SYSTEMS

7.0.0

Schlumberger uses pressure-vacuum bulk systems at some Districts. A pressure-vacuum system uses basically the same components found in pressure bulk systems, except that the compressor must be designed for a pressure-vacuum application and requires an additional filter process for the compressor.

7.1 Principle of operation

The principle of moving material by vacuum is the same as that for a pressure system. Air carries the bulk material from areas of high pressure to areas of low pressure. A vacuum system creates low pressure in the tank to which the product will be transferred while fluffing and jetting the tank from which the product will come. Bulk product is carried faster through this type of system. The compressor is plumbed so that the inlet creates a vacuum while the discharge is

simultaneously expelled to the atmosphere, pressurizing the tank.

The bulk tanks are plumbed in such a way that the air used to carry the bulk material out of the tank comes through the tank’s vent system, pulled in by the compressor. In most new plants, three separate units are used for pressure/vacuum systems.

A pressure-vacuum system has the following advantages over a straight pressure bulk system: less dust is generated when adding additives to the WBB; the bulk tanks are easier to clean, the cost of the tanks is lower, and the code is not needed.

The primary disadvantage is that the reciprocating compressor has a short life span if it is not maintained correctly.

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N

ON-PRESSURE BULK TANKS

7.2.0

Non-pressure tank

7.2 Non-pressure bulk tanks

(zero pressure)

Non-pressure bulk tanks used in pressure-vacuum systems are constructed as shown here. Most components of the tank perform the same function as when used on a

pressure tank. The components with different functions are described below. Pressure/ vacuum plants require zero pressure tanks for storage containers. They require a full open (preferred 5-in) vent on top of the tanks to a vent collection tank. This tank has a single line going to the dust collector, which sits on top of a dust collection tank. The vent tank is also the blow-down tank for products being returned to the plant at the completion of the job.

7.2.3 Pressure relief valve

Since these silos are non-pressure tanks, they must be equipped with a vacuum valve to prevent collapse.

All storage tanks on the inlet side of the WBB require a full open vent on top of the tank for each individual product stored, and a 2-in vacuum breaker on the tank.

All stored products and additives enter the WBB by means of vacuum, and the blending/ transfer to the transport unit occurs through the pressure process.

7.2.1 Vent line

The vent line allows air to enter the tank, and does not have a valve. Being a full open vent, it does not require a pressure relief valve.

7.2.2 Vacuum breaker

The tank has a vacuum relief system to prevent the tank from collapsing if the vent becomes plugged.

Fill line Vacuum breaker

Manway

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Air compressor components in pressure vacuum systems

7.2.4.1 Air compressor

An air compressor used in a pressure-vacuum system works very much like an air compressor in a pressure system. The key difference is that the compressor in a pressure-vacuum system includes flow selector valves.

Flow selector valves determine whether the compressor pulls air in from the atmosphere and discharges it to the WBB, or if it pulls air in from the WBB. The compressor has an additional filter on its suction to prevent pulling in dust when acting as a vacuum pump. This plant may incorporate the use of two separate pumps, one for pressure and one for vacuum. The new plants use a Sullivan Palatek

compressor for pressure and a DVT vacuum pump for vacuum.

In an emergency, the Palatek unit can be used as both a pressure and a vacuum pump when the valve arrangement is properly set up to

PRESSURE VACUUM COMPRESSORS

7.2.4

accommodate both. This occurs when the DVT unit fails.

Palatek compressor (above) and DVT vacuum pump(below)

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W

EIGH BATCH BLENDER

7.3.0

Weigh batch blender

A weigh batch blender (WBB) used in a pressure-vacuum system is built to work both as a vacuum tank and as a pressure tank. In addition to the features explained earlier, the WBB has a built-in dust collector located at the top of the tank. This section filter prevents the compressor from pulling dust from the tank when it is being used as a vacuum pump.

The WBB is evacuated through a filter by the compressor to create the low pressure needed for the system to blend and move material by vacuum. The WBB is also used as a pressure tank to blend and move material back out of the tank.

New versions of the WBB have a separate dust collector (metroplex) on top of the tank. This is a dry filter type with a purge/ surge cleaning device incorporated into the dust collector. All products including additives enter the WBB via separate lines. Therefore, if five products are stored in bulk, you will use five openings on top of the WBB, plus one for dry additives. Most WBBs have eight openings on top of a 5-in groove lock type. This new type of tank does not require the use of a vacuum breaker.

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A

DDITIVE HOPPER

7.4.0

In a pressure/vacuum plant the additive bottle is replaced by an additive cone operating under vacuum. Additives are dumped into a hopper and the rate of flow is controlled by a butterfly valve at the base of the cone (hopper).

The vacuum on the WBB is created by the vacuum pump and the vacuum on the weight batch blender. Upon completion of the process, the additive valve is closed and the products are blended and then transferred to the bulk transport.

One of the advantages of a pressure-vacuum system is its additive hopper. The hopper relies on a vacuum to pull the additives into the WBB, thus eliminating much of the dust created when adding sacked additives. This process may also be assisted by jets in the material line between the additives cone and the WBB.

Upper clean out jet

Cone

Lower clean-out jet Vacuum

vent valve

Cone base valve control Removable product screen Vent hood Material valve control

Lower and upper clean-outs

5 in material valve Material line to the WBB

Additive hopper

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Non-Blend Field blend Vent Vacuum

Non-pressure tanks

Dust tank

Truck mix tank

Double-stack tank

W

eight

batch blender

Vacuum pump

Palatek compressor

Dust collector

Pressure/vacuum bulk plant system

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B

ULK EQUIPMENT OPERATIONS

8.0.0

Bulk truck

8.1.0 operating bulk equipment on

location

8.1.1 SteM 1

All bulk equipment must be well maintained and be inspected before and after every job. Equipment used to transfer cement from the District to location must pass a STEM 1 inspection before it is dispatched from the District and as soon as the equipment reaches location. This ensures that the equipment was not damaged en route to the job site. Make sure that the equipment is green-tagged and STEM 1 paperwork is completed on the bulk equipment in the same way you would perform an inspection of the pumping equipment. Equipment that is not operational should be red-tagged and repaired as soon as possible.

8.1.2 Rigging up

Equipment should be spotted to keep the bulk discharge lines as short as possible. The longer the line, the more air is required to transport the bulk material.

As the use of air increases, the amount of dust created while moving the bulk material will increase as well.

If portable air lines are rigged up on location, blow air through them before hooking up to ensure that the lines are clear of water and dirt; also, be sure they are of proper construction to prevent parting.

8.1.3 transferring bulk material on location

Many jobs performed by Schlumberger require cement material to be transferred on location. It is sometimes better to store bulk material in portable P-tanks or gravity silos rather than trying to fit all of the material on location in bulk trucks.

On larger jobs, there are several benefits to using large bulk storage tanks instead of relying on bulk trucks to supply the mixing equipment:

• Making multiple trips to the location with the same truck(s) can reduce the number of

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Follow these steps when transferring material on location:

• Each bulk truck must have a completed load sheet. This sheet will list the amount and type of material that is in each tank.  • Each storage tank must pass a STEM 1

inspection before being carried to location. The FSM or FS/FE assigned to the job has determined the type of material that will be loaded into each storage tank on location. A sketch of the location showing where each load is to go must be given to the FS. The storage tank should be checked before it is loaded to ensure that it has not been damaged on the way to the location.

Each field storage tank should be clearly marked with its contents. A field test blend sample must be taken during the loading. The proper equipment to rig up the truck to the storage tank and the storage tank to a dust control system must be available. The exit of the dust control system must be routed so that the chance of exposing personnel and equipment to dust is minimized.

Most locations have rules that require dust control when transferring cement. An operational dust control system is required on every job. The dust control device must be hooked up before moving cement.

Two dust collectors devices are CUS-917 - Dust Collector (Cut Sheet), InTouch content ID# 3994426; and CUS-900 - Dust Collector (Cut Sheet), InTouch content ID #3994401. If there are two or more compressors on location, be sure to connect them together to provide backup for each other. The use of disposable dust bags may be required. bulk trucks required to do the job.

• The number of people required to do the actual job can be reduced. A driver for each bulk truck is required if all the material is brought to location at the time of the job. • Large bulk tanks take up less space than

the number of bulk trucks needed to hold the same volume of material. This is an important consideration for small locations. • Fewer hoses, connections, etc. are required

to hook up the large bulk tanks than would be required to hook up the number of bulk trucks holding the same volume.

• Fewer tanks require fewer tank changes. Switching from an empty tank to a full tank causes the flow of cement material to the mixer to change, which can cause the slurry density to vary.

JET Module6_Bulk System

JET Module 6

Bulk System

T

ABLE OF CONTENTS

TOC

1 Introduction

pg 5

2 Principles of operation

pg 6

2.1 Purpose of a bulk system

pg 6

2.2 Basic bulk system components

pg 7

2.3 Principles of pneumatic conveying

pg 8

2.4

2.4 Principles of vacuum conveying

pg 13

3 Bulk systems

pg 14

3.1 Bulk storage tanks

pg 14

3.2 Pressure tank

pg 16

3.2.1 Components of pressure tank

pg 16

3.2.2 Weigh batch blender

pg 21

3.2.3 Additive/cutting bottle

pg 22

3.2.4 Bulk tank construction

pg 22

3.3 Gravity discharge bulk tanks

pg 24

3.3.1 Discharge valve

pg 25

3.3.2 Air supply line

pg 25

3.3.3 Aeration device

pg 25

3.3.4 Sight glass

pg 26

3.3.5 Weight indicator

pg 26

3.4 Pressurized surge can

pg 27

3.4.1 Vent line

pg 27

3.4.2 Pressure sensor

pg 27

3.4.3 Pneumatic controller

pg 28

3.4.4 Side discharge

pg 28

3.5 Air slide/commercial hauler

pg 29

4 Air compressors

pg 30

4.1 Reciprocating compressors

pg 30

4.2 Rotary axial compressors

pg 32

4.3 Vane-type compressors (blowers)

pg 33

4.4 Compressor package

pg 34

4.4.1 Compressor

pg 34

T

ABLE OF CONTENTS

TOC

4.4.3 Power unit

pg 34

4.4.4 Air receiver tank

pg 34

4.4.5 Safety relief valve (PRV)

pg 34

4.4.6 Pressure gauge

pg 35