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.
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 ΔP, a short flame and high reliability. 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 converted into methanol via the Casale plate-cooled converter (12), characterized 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 (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 remaining inerts (17) are sent to the primary reformer (4) as a fuel.
The raw methanol (14) is sent to the distillation section (18), comprising three columns, where byproduct and contained water are separated out to obtain the desired product purity (19).
Licensor: Methanol Casale SA, Switzerland