Syngas Preparation Processes

Recalling that methanol may be produced by the following reactions  

S values of approximately 2.0 are representative of stoichiometric syngases. H2-rich syngases have S values that are greater than 2.0. 

AU the aforementioned front-end process routes exhibit varying efficiencies, capital costs, and operating complexities. No single route is best, but a particular route is likely to be best under certain project- and/or site-specific circumstances. Project specifics generally dictate the preferred synthesis gas generation route. In this section, each of these routes is reviewed briefly for purposes of comparison. 

Coal gasification is accomplished by a combination of partial oxidation and hydro ification of coal feedstock according to the following chemical reactions  

Low Btu value gas is typically produced when air is used as the oxidant. The heating value improves markedfy when pure oxygen is substituted for air. 

---

BaTiOj precursor can be formed by sol-gel method under appropriate condition, and nanometer BaTiOj is prepared by further calcining the precursor at 973K. Solvent, temperature, pH value and water volume for hydrolysis have great effect on the quality of BaTiOj powders in the process of preparing precursor. Nanometer BaTiOj is used as support to prepare Ni based catalyst, and the catalyst has high activity in the reaction of CO2 reforming CH4 to syngas. 

Electron-transfer processes can give rise to substitution-labile 17-electron complexes . A 17-electron species prepared by electrochemical methods favors CO reaction with ( -Cp)2TiCl2. Electron-transfer catalysis has been proposed for the conversion of FcjfCO), 2 to FefCO) . A possibly related process is the transformation of Rh4(CO), 2 into [Rh(CO)4] under syngas pressure. This may be an important step in the synthesis of ethylene glycol from CO and H2. 

If methanol can be considered to be the intermediate in a multistep reaction to form a final species, e. g., gasoline as in the Mobil MTG process [4], then a bifunctional catalyst ought markedly to increase the utilization of the syngas. Since in the MTG process dimethyl ether (DME) is a key intermediate, Sofianos et al. [9] proposed for this purpose a bifunctional catalyst, prepared by intimate mixing of finely milled samples of the methanol catalyst and of y-alumina, the acid catalyst which dehydrates methanol to DME. The results obtained show that the CO conversion using the bifunctional catalyst is nearly four times higher than that obtained with the monofunctional catalyst. 

Catalysts were prepared by washcoating. Ce02 -promoted Rh catalyst exhibited the highest activity and selectivity to syngas. Addition of steam in the reaction feed increased the H2 selectivity and decreased CO selectivity. The process produced H2-rich gas containing large amount of CO. 

Zeolites are also used in the non-cryogenic purification of hydrogen by the adsorption of water, CO2, N2 and hydrocarbons and in the removal of residual CO2 and H2O from syngas mixtures prepared by reforming natural gas according to the reaction CH4+H2O CO + 3H2. These processes are important... 

The conversion of methanol to hydrocarbons is the most studied reaction of oxygenates over microporous solids, for both commercial and academic reasons. Methanol can be generated from syngas over copper- and zinc-based catalysts using the ICI process, and syngas can be prepared from methane, which is a readily available resource. Under the correct economic conditions, methanol conversion reactions can provide an important route to higher... 

---