We initially apply “cryogenic liquefaction” and “cryogenic distillation” in extracting methane from the coke oven gas for LNG, which has a maximum effective components recovery rate. Also, it has the advantage of high product recovery rate, high product purity, low operating cost and high return on investment. The technology is different from traditional LNG process, in which methane content of material gas is as high as 95% and qualified LNG products can be obtained by simple liquefaction. The methane content of coke oven gas is usually 20% - 30%, however, traditional LNG process with a minimum liquefaction temperature of -165℃can’t separate the methane from hydrogen-nitrogen effectively. To meet the requirements of LNG products, the methane recovery rate should be low without good economic benefits.
Therefore, according to the obvious difference of boiling point between nitrogen, hydrogen and methane, the cryogenic distillation technology was applied in coke oven gas for LNG. The methane recovery rate of raw material gas was greatly improved to be more than 98%.
Typical case
By 2013, in the industrialized device of “Xinwen mining Inner Mongolia Energy Co., Ltd. 120 million m3/ y coke oven gas for LNG project” constructed by us, the methanation and mixed refrigerant refrigeration process were firstly applied to the comprehensive utilization of coke oven gas in the word . The success of whole process trial production marked a new breakthrough in coke oven gas for LNG. The advanced and reliable technology make full use of effective components of coke oven gas, greatly improving the added product value with a remarkable economic and social benefit, which in turn promote the development of green energy.
