Synthetic process flow with Ru catalysts

The characteristics of Ru catalyst are high activity (concentration), intense inhibition of hydrogen, insensitivity to ammonia, high catalyst cost and so on. In view of engineering applications, first, its high activity can be used to operate in low temperature and low pressure where there is the possibility to realize S3mthetic process of non-circulation second, it is suitable to be applied to the process at low ratio of H2 to N2 because of its intense inhibition of hydrogen third, it is suitable to be co-used with Fe catalyst since it is insensitive to ammonia and simultaneously this also reduces the amount of Ru catalyst used. Therefore, many kinds of new synthesis processes flow have been proposed. 

1-Syngas compressor 2-Circulat compressor 3,4-Separating-hydrogen devices 5-Separator 6,11,12-Cooler 7-Cool-exchanger 8,9,10-Converter. 

8% CH4 and 1.5% Ar after reaction is cooled to 40°C in the interchanger 7, and is then continuously cooled to —33°C in the cooler 6. The condensed ammonia is separated from the separator no. 5, and the residual gas is recycled to the inlet of compressor 2. The vent gas (7% H2) is sent to the H2 separator 4, where H2-rich gas (85% H2) is obtained and mixed with recycle gas. 

The N2-H2 ratio is stoichiometric at all points in the traditional synthesis loop. But, at low N2-H2 ratio loop, N2-H2 mixture with the mole ratio of H2 to N2 at inlet is 2 (1-0.671) (1 1 will be better) is sent into a converter. During the reaction process, it keeps stoichiometric ratio, but because the raw material with H2/N2 of 1 1 is sent into the converter, more H2 is consumed than N2, so H2 is needed to be complementary to the system in order to maintain the proportion needed. For example, someone suggested that H2 could be injected to every point of the system respectively.  

The experiment means that the fresh syngas whose molar ratio of H2 to N2 is (1.7-2.5) is mixed with the recycle gas current, and the molar ratio of H2 to N2 increases to (0.5-1.7) by separating H2 from vent gas. The mole ratio of H2 to N2 of the syngas entering the converter is (0.8-1.8) l. In this situation, the space velocity ratio of the recycle gas to the fresh gas is (2.2-3.7) l. 

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