Syngas composition

The observed effects of syngas composition on both the CO conversion and the product selectivity, again, are in agreement with data already reported.1112141819 For example, Schulz and Claeys18 observed that when increasing CO partial pressure by decreasing the H2/CO inlet ratio, both the rate of CO consumption (and thus CO conversion) and the selectivity to methane decrease, while the selectivity to the heavier products increases. 

Effect of Operating Conditions. Yield data, summarized in Figures 1 and 2, point to acetic acid homologation activity being sensitive to at least four operating variables, viz. ruthenium and methyl iodide concentrations, syngas composition and operating pressure. 

Figure 2. Acetic acid homologation (%) acetic acid, propionic acid, (A) butyric acids, and (Y) valeric acids, ( Z ) ethane A, effect of syngas composition (operating conditions acetic acid, 833 mmol Ru(IV) oxide, 4.0 mmol Mel, 40 mmol 220°C 272 atm initial pressure) B, effect of operating pressure (operating conditions acetic acid, 417 mmol Ru(IV) oxide, 2.0 mmol Mel, 20 mmol 220°C constant pressure CO/H2 = 1/1)...

Syngas composition varies based on many factors, including reactor type, feedstock, and processing conditions (e.g., temperature, pressure, type reactant, etc.). In turn, specific end-use... 

Fig. 5 Activity of Rh-3-SILP catalyst at different syngas compositions (pH2 Pco ratios) and temperatures (Reaction conditions T = 100°C, ptotai = 10bar) [32]...

Syngas composition, most importantly the H2/CO ratio, varies as a function of production technology and feedstock. Steam methane reforming yields H2/CO ratios of three to one whereas coal and biomass gasification yields ratios closer to unity or lower. Conversely, the required properties of the syngas are a function of the synthesis process. Fewer moles of product almost always occur when H2 and CO are converted to fuels and chemicals. Consequently, syngas conversion processes are more thermodynamically favorable at higher H2 and CO partial pressures. The optimum pressures depend on the specific synthesis process. 

Table 3 Typical Syngas Composition from Different Tests...

Figure 4.14 shows the effect of coal concentration in the slurry on the syngas composition. It is shown that increasing coal concentration is helpful for a higher... 

Figure 4.14. Effect of coal concentration in slurry on syngas composition.

Typical temperatures of Shell gasifiers are in the range of 1440-1600 °C. The typical 02 consumption rate of Shell gasifiers is 0.9 kg 02/kg of coal (on a dry, ashfree basis). The ratio of steam consumption to 02 consumption ratio is 0.14. The cold syngas efficiency is -82% and the carbon conversion can reach >99%. The wet syngas compositions (mol %) from the gasification of a Cerrejon coal from Columbia are... 

Figure 1. Variation of syngas compositions with pressure (at 1000°C).

The capital cost of the synthesis gas often accounts for more than 50% of the cost of the complete plant. The optimal choice of technology depends upon the size of the plant and the desired syngas composition for the subsequent synthesis. In Table 1, the optimum syngas composition for a range of final products is given. ... 

Syngas composition for SOFC not included in Ref. f Polymer electrolyte fuel cell. 

The optimum technology for producing a syngas with a desired composition depends on the feedstock and the capacity. A very important parameter in selecting the best technology is the desired H2/CO ratio. In Fig. 14, the syngas composition, which may be produced by various technologies with natural gas and naphtha feedstock, is illustrated. 

For all fuel/62 feed composition above the syngas ratio, solid graphite is thermodynamically stable at all temperatures, and at lower temperatures it is an equilibrium product even at the syngas composition. Therefore, the reaction ... 

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