Commercial plants: A total capacity of 299,000 metric tpy has been licensed since 1993 within 17 plants. The latest plant, with a capacity of 50,000 metric tpy, was commissioned in October 2009 at the Sichuan Golden Elephant Chemical Industrial zone, Meishan, Sichuan, China.
Recently, the list of references has been extended by a 50,000 metric tpy melamine plant to be started up in Russia in 2011.
Licensor: Edgein S&T Co. Ltd./Lurgi GmbH, a company of the Air Liq-uide Group - CONTACT
Petrochemical Processes 2010 2010
Petrochemical Processes Home Process Categories Company Index
Methanol
Application: To produce methanol from natural gas. The process is based on Casale highly efficient equipment including: The Casale plate cooled technology for the methanol converter.
Description: The natural gas (1) is first desulfurized before entering a primary reformer (2), where it is reformed, reacting with steam to gen-erate synthesis gas, i.e., hydrogen (H2), carbon monoxide (CO) and car-bon dioxide (CO2). The reformed gas is cooled (3) by generating high-pressure (HP) steam, which provides heat for the methanol distillation columns (8). The cooled gas enters the synthesis gas compressor (4), where it is compressed to synthesis pressure.
The compressed syngas reaches the synthesis loop where it is con-verted to methanol in the Casale plate-cooled converter (5), character-ized by the highest conversion per pass and mechanical robustness. The heat of reaction is used to generate directly medium-pressure steam.
The gas is cooled (6), and raw methanol (7) is condensed and separated, while the unreacted syngas is circulated back to the converter.
The raw methanol (7) is sent to the distillation section (8), compris-ing two or three columns, where byproducts and contained water are separated out to obtain the desired purity for the methanol product (9).
The inerts contained in the synthesis gas are purged from the loop (10) and recycled as fuel to the primary reformer (2).
Economics: Thanks to the high efficiency of the process and equip-ment design, the total energy consumptions (evaluated as feeds + fuel + steam import from package boiler and steam export to urea) is about 7 Gcal/metric ton of produced methanol.
Licensor: Methanol Casale SA, Switzerland - CONTACT
1 2
3 4 6
5
7 9 8
Petrochemical Processes 2010 2010
Petrochemical Processes Home Process Categories Company Index
Copyright © 2010 Gulf Publishing Company. All rights reserved.
Methanol
Application: To produce methanol from natural gas. The process is based on Casale’s highly efficient equipment, including its:
• Casale axial-radial pre-reformer
• Casale high efficiency design for the auto-thermal reformer (ATR)
• Casale plate-cooled technology for the methanol converter.
Description: The natural gas (1) is first desulfurized before entering a prereformer (2) where methane and other hydrocarbons are reacted with steam to be partially converted into synthesis gas, i.e., hydrogen (H2), carbon monoxide (CO) and carbon dioxide (CO2). The pre-reformer is designed according to the axial-radial technology for catalyst beds from Casale. The partially reformed gas is split (3) in two streams, one entering a primary reformer (4), where the reforming process is further advanced. The second stream joins the first (5) at the primary reformer (4) exit, and the streams enter the ATR (6) where oxygen (7), from air (8) in the air separation unit (9) is injected, and the methane is finally converted into syngas. In this unit, Casale supplies its high-efficiency process burner, characterized by low P, a short flame and high reli-ability. The reformed gas is cooled (10) by generating high-pressure (HP) steam, which provides heat to the methanol distillation columns (18).
The cool reformed gas enters the synthesis gas compressor (11), where it is compressed up to the synthesis pressure.
The compressed syngas reaches the synthesis loop where it is con- verted into methanol via the Casale plate-cooled converter (12), char-acterized by the highest conversion per pass and mechanical robust-ness. The heat of reaction is used to generate directly medium-pressure steam. The gas is cooled (13), and the raw methanol is condensed and separated (14), while the unreacted syngas is circulated back to the converter. The inerts (15) contained in the synthesis gas are purged from the loop, and the hydrogen contained is recovered in a hydrogen
recovery unit (HRU) (16) and recycled to the synthesis loop. The remain-ing inerts (17) are sent to the primary reformer (4) as a fuel.
The raw methanol (14) is sent to the distillation section (18), com-prising three columns, where byproduct and contained water are sepa-rated out to obtain the desired product purity (19).
Economics: Thanks to the high efficiency of the process and equipment design, the total energy consumption (evaluated as feeds + fuel + steam import from package boiler and steam export to urea) is about 6.7 Gcal/
metric ton of produced methanol. Very high capacities are achievable in single-train plants, with one synthesis reactor capacity approaching 10,000 metric tpd.
Commercial plants: Four ATR plants are in operation, one 7,000 metric
Petrochemical Processes 2010 2010
Petrochemical Processes Home Process Categories Company Index
Methanol
Application: The Davy Process Technology–Johnson Matthey process is a low-pressure methanol process. The process produces methanol from natural or associated gas via a reforming step or from syngas generated by the gasification of coal, coke or biomass. The reforming step, also available from this licensor, may be conventional steam reforming (SMR), compact reforming, autothermal reforming (ATR), combined reforming (SMR + ATR) or gas-heated reforming (GHR + ATR). The reforming or gasification step is followed by compression, methanol synthesis and distillation (one, two or three column designs) Capacities up to 7,000 metric tpd, are practical in a single stream and flowsheet options exist for installation of the process offshore on FPSO vessels.
Description: The following description is based on the SMR option. Gas feedstock is compressed (if required), desulfurized (1) and sent to the optional saturator (2) where most of the process steam is generated.
The saturator is used where maximum water recovery is important and it also has the benefit of recycling some byproducts. Further process steam is added, and the mixture is preheated and sent to the optional pre-reformer (3), using the Catalytic-Rich-Gas (CRG) process. Steam raised in the methanol converter is added, along with available carbon dioxide (CO2), and the partially reformed mixture is preheated and sent to the reformer (4). High-grade heat in the reformed gas is recovered as high-pressure steam (5), boiler feedwater preheat, and for reboil heat in the distillation system (6). The high-pressure steam is used to drive the main compressors in the plant. After final cooling, the synthesis gas is compressed (7) and sent to the synthesis loop. The loop can operate at pressures between 50 bar to 100 bar. The converter design does impact the loop pressure, with radial-flow designs enabling low loop pressure even at the largest plant size. Low loop pressure reduces the total en-ergy requirements for the process. The synthesis loop comprises a circu-lator (8) and the converter operates around 200°C to 270°C, depending on the converter type.
Reaction heat from the loop is recovered as steam and saturator water, and is used directly as process steam for the reformer. A purge is taken from the synthesis loop to remove inerts (nitrogen, methane), as well as surplus hydrogen associated with non-stoichiometric operation.
Also, the purge is used as fuel for the reformer.
Crude methanol from the separator contains water, as well as trac-es of ethanol and other compounds. Thtrac-ese impurititrac-es are removed in a two-column distillation system (6). The first column removes light ends such as ethers, esters, acetone and dissolved noncondensable gases.
The second column removes water, higher alcohols and similar organic heavy ends.
Copyright © 2010 Gulf Publishing Company. All rights reserved.
Copyright © 2010 Gulf Publishing Company. All rights reserved.