Synthesis gas generation

Methods for the large-scale production of hydrogen must be evaluated in the context of environmental impact and cost. Synthesis gas generation is the principal area requiring environmental controls common to all syngas-based processes. The nature of the controls depends on the feedstock and method of processing. 

Synthesis Gas Generation Routes. Any hydrocarbon that can be converted into a synthesis gas by either reforming with steam (eq. 4) or gasification with oxygen (eq. 5) is a potential feedstock for methanol. 

With these waste-minimization techniques, methanol synthesis is relatively clean, and poses no unique environmental hazards. The need for environmental controls is more closely associated with the synthesis gas generation process. 

Between 1930 and 1950, the primary emphasis of ammonia process development was ia the area of synthesis gas generation (3) (see Fuels, SYNTHETIC, GASEOUS FUELs). Extensive coal deposits ia Europe provided the feedstock for the ammonia iadustry. The North American ammonia iadustry was based primarily on abundant suppHes of low cost natural gas (see Gas, natural). 

Synthesis Gas Preparation Processes. Synthesis gas for ammonia production consists of hydrogen and nitrogen in about a three to one mole ratio, residual methane, argon introduced with the process air, and traces of carbon oxides. There are several processes available for synthesis gas generation and each is characterized by the specific feedstock used. A typical synthesis gas composition by volume is hydrogen, 73.65% nitrogen, 24.55% methane, <1 ppm-0.8% argon, 100 ppm—0.34% carbon oxides, 2—10 ppm and water vapor, 0.1 ppm. 

Synthesis gas generation routes, for methanol, 16 302-307 Synthesis gas mixture ( syngas ), 73 842, See also Syngas plants Synthesis loop, methanol, 16 307... 

Synthesis gas generation Process in which light hydrocarbons are partially oxidized over a catalyst at about 875 K with oxygen and the carbon monoxide is shifted with steam to produce CO and H. ... 

The objective of tiie research described here is to explore synthesis gas generation by direct oxidation of CH4 (reaction 3). A reactor giving complete conversion to a 2/1 mixture of H2 and CO would be the ideal upstream process for the production of CH3OH or for the Fischer-Tropsch process. As discussed above, currently implemented or proposed processes utilize a combination of oxidation and reforming reactions to generate synthesis gas from CH4 and O2. In this work, we seek a faster, more efficient route of syngas generation in which H2 and CO are the primary products of CH4 oxidation. It is expected that this may be difficult because... 

The treatment of a cobalt(II) salt with synthesis gas generates sequentially Co2(CO)8 then HCo(CO>4. This catalyst is generated only at 120-140 C for the carbonylation to proceed smoothly 200-300 bar is required to stabilize the catalyst. If the hydridocobalt catalyst is prepared separately and then introduced into the reaction, temperatures as low as 90 C can be used for the hydrocarbonylation. An important consideration in industrial reactions is the normal to branched nib ratio to give the desired straight chain aldehyde, the hydridocobalt catalyst providing an nib ratio of -4 in the hydroformylation of propene under the lower temperature conditions. This catalyst will stoichiometrically hydroformylate 1-alkenes under ambient conditions. 

The synthesis gas generation process is a noncatalytic process for producing synthesis gas (principally hydrogen and carbon monoxide) for the ultimate production of high-purity hydrogen from gaseous or liquid hydrocarbons. 

The Fischer-Tropsch synthesis of hydrocarbons is used on a large scale for fuel production in South Africa [78, 79]. Synthesis gas generated from coal in Lurgi fixed-bed gasifiers enters the Synthol reactor (Fig 18), where it is reacted over an iron catalyst at 340°C. The reactor works on the principle of the circulating fluidized bed. The mean porosity in the riser is 85%, and the gas velocity varies between 3 and 12ms1 [2]. Reaction heat is removed by way of heat-exchanger tube bundles placed inside the riser. 

The process is exothermic, and the heat released by the methanol synthesis is used to partially heat up the natural gas for the endothermic synthesis gas generation. 

The catalytic conversion of hydrogen and nitrogen to ammonia is basic to all processes, while the synthesis gas generation step (hydrogen generation) varies considerably depending on the type of raw material used. 

Thus, as technologies develop in all these areas of ammonia synthesis gas generation, there will be a new set of guidelines for analyzing the relative economics of alternate feedstocks. 

Child, E. T. Marion, C. P., "Recent Developments In The Texaco Synthesis Gas GEneration Process", Presented at The Fertilizer Association Of India National Seminar, December 14-15, 1973, New Delhi. 

The following is a brief description of synthesis gas generation from the various accepted feedstocks. 

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