Synthesis Gas Production By Co-gasifying Coal And Natural Gas

Synthesis gas can be generated either by steam reforming of natural gas, which is based natural gas only, or by coal gasification in which coal only. However, many problems are accompanied with the gasification processes consuming sole material. Natural gas to syngas process is short, clean, efficient, while the high price for natural gas, high H2/CO ratio, and high network prices has seriously restricted the promotion of natural gas. The H2/CO ratio of coal gasification is often improved through the CO shift unit, so a large amount of CO2 discharge is unavoidable, also load of pickling section and running costs were increased. In addition, high investment and environmental pollution for coal gasification does not meet the requirements of sustainable development. Therefore, synthesis gas production by co-gasifying coal and natural gas was proposed, in order to reduce the production cost and CO2 emission, and realize the H2/CO ratio adjustable. The main works were included:The reaction process was analyzed on synthesis gas production by co-gasifying coal and natural gas from the thermodynamic point of view, from which relationship between the equilibrium constant and the temperature is calculated, also the competition ability of the reactions in the process is compared.Synthesis gas production by co-gasifying coal and natural gas was analyzed with Aspen Plus. The effects of parameters, such as reaction pressure, coal water slurry, oxygen flow rate and natural gas flow rates on the temperature of synthesis gas, the gas mole composition, the syngas mole fraction and H2/CO ratio were analyzed. The oxygen and natural gas flow rates were calculated which the outlet gas temperature between 1340 oC and 1360 oC, H2/CO ratio is large than 1.15, the synthesis gas mole fraction is greater than 0.72.Synthesis gas production by co-gasifying coal and natural gas process based on Texaco was studied by using FLUENT software. The calculated temperature and composition of the outlet gas were obtained, and the flow field and gas composition distribution were predicted. The results agreed well with the Texaco gasification model presented. It was also found that the results between Aspen Plus and FLUENT has little difference, indicating the numerical model was reasonable.