Cleanup methanation

Among these permanent poisons, sulfur is the most common. In some plants based upon gasification of coal or oil, traces of COS and H2S may reach the synthesis converter. In natural-gas-based plants, the Cu-based low temperature shift catalyst and the Ni-based cleanup methanation catalyst act as efficient guards. In most cases the sulfur poisoning is caused by lubricating oil. Thus, it has been considerably reduced by the use of low sulfur oil and centrifugal compressors instead of piston compressors [1]. 

Note that the methanation section is the last processing step in the HYGAS pilot plant, and it depends on the steady-state troublefree operation of the preceding steps (the gasification reactor, amine purification, and caustic wash sections for cleanup sulfur removal) before it can be brought on-line. 

Aqueous distillates are extracted, usually with dichloro-methane (DCM), concentrated to small volumes, generally in a Kuderna-Danish evaporator, and examined by gas chromatography (GC) using a specific detection system. Additional chromatographic cleanup may be required, depending on the complexity of the sample and specificity of the chromatographic detector. 

A La(Cr, Ni) 0, catalyst was tested for the cleanup of residual hydrocarbons in combustion streams by measuring the rate of methane oxidation in a differential laboratory flow reactor containing a sample of the catalyst. The following conversions were measured as a function of temperature with a fixed initial molar flow rate of methane. The inlet pressure was 1 bar and the methane mole fraction was 0.25. (Note that the conversions are small, so that the data approximately represent initial rates.) The rate law for methane oxidation is first-order with respect to methane concentration. 

Sewage sludge Ultrasonic solvent extraction into methanol/dichloro-methane, cleanup with reverse phase extraction cartridge, dissolved in methanol LC-APCI-MS 50 ng/g 78 Petrovi and Barcelo 2000... 

When Drasch and colleagues (1987) determined the concentration of sulfur mustard in tissues of a deceased victim, they had to employ a combination of dichloro-methane extraction, a thin layer chromatography cleanup on silica plates, followed by derivatization with gold chloride. 

Typical anaerobic digestion facilities can contain hydrolysis units, digesters, gas cleanup and dehydration units, and liquid effluent treatment units, as illustrated in Fig. 12.7. Many improvements have been incorporated into the ancillary unit operations as well as the methane fermentation process itself. 

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