Technology for Manufacture of Natural Gas through Isothermal Methanation Passed Appraisal

The technology for manufacture of natural gas through isothermal methanation of coke oven gas jointly developed by the Shanghai Huaxi Chemical Science and Technology Co., Ltd., the Anhui East China Chemical and Pharmaceutical Engineering Co., Ltd., and the Shanghai Hanxing Energy Science and Technology Co., Ltd., has passed the review and appraisal. This technology has been successively applied in the 8 500 m3/h unit for manufacture of LNG from coke oven gas at the Unicorn Gas Energy Company in Qujing city, Yunnan province and in the 17 000 m3/h unit for manufacture of LNG from coke oven gas at the Jianyuan Coal Carbonization Company in Inner Mongolia, with all units running smoothly at long cycles. The commercial operation results have shown that this technology features short process scheme, low investment cost, small plot plan, low energy consumption and simplicity in operation, which can leave out the decarburization process to reach a CO conversion of 99.95% and a CO2conversion of 99.9%.

This technology has high tolerance and adaptability to high content of CO and CO2in coke oven gas and can achieve high conversion with the total content of CO +CO2at the reactor outlet being lower than 50 ppm. The LNG product contains more than 99% of hydrocarbons, among which the methane content exceeds 97% with a high caloric value of 37.57 MJ/kg. The product LNG gas contains less than 100 ppm of carbon dioxide with zero content of hydrogen sulfide, and the product quality exceeds the national quality standard. 2.6 volumes of coke oven gas can produce one volume of LNG at an LNG output ratio of 1:2.6. For example, an 1.0 Mt/a coal carbonization unit can produce a byproduct coke oven gas totaling 25 000 m3/h, which can be used to manufacture LNG via the one-step isothermal methanation technology to save an engineering investment cost of 20 million RMB and an overseas patent license fee of around 15 million RMB along with a saving in 200 kWh of power per hour and a saving in annual operating cost of 1.5 million RMB.