System and method for preparing LNG from medium and low temperature dry distillation raw coke oven gas through sulfur-resistant uniform-temperature methanation

Abstract

The invention discloses a system and method for preparing LNG from medium and low temperature dry distillation raw coke oven gas through sulfur-resistant uniform-temperature methanation, and belongs to the technical field of clean and efficient utilization of coal. Tar recovery is carried out after dedusting, deamination and purification on the dry distillation raw coke oven gas to obtain a high-value by-product; and advanced hydrocarbons such as propane, butane and the like are pressurized, liquefied and separated to directly prepare LPG. H2S gas desorbed by a desulfurization and decarburization device is high in purity, and sulfur can be recovered by adopting a Claus sulfur recovery process. The content of an LNG component CH4 obtained after cryogenic liquefaction separation is high andis greater than 95%, so that the requirements of a first-grade natural gas product are met. The system is easy and convenient to operate, clean and efficient utilization of low-rank coal is achieved through the low-temperature dry distillation poly-production technology of coal, liquefied natural gas with the high calorific value is produced, byproducts such as tar, LPG, sulfur and carbon dioxideare by-produced, energy is saved, and economic benefits are high.

Description

technical field [0001] The invention belongs to the technical field of clean and efficient utilization of coal, and specifically relates to a system and method for producing LNG (liquefied natural gas) through sulfur-resistant and uniform-temperature methanation of medium-low temperature dry distillation of raw coal gas. Background technique [0002] Natural gas, as an efficient, clean and safe fossil energy, has increased its proportion in global energy consumption year by year; with the enhancement of people's awareness of environmental protection and the improvement of quality of life, the demand for natural gas has increased year by year, and the use of relatively abundant coal reserves Resources, in-depth development of low-temperature carbonization and co-production of natural gas technology for low-quality coal, using raw coal gas with low calorific value, transforming it into environmentally friendly natural gas, not only realizes the comprehensive utilization of coal ...

AI Technical Summary

Problems solved by technology

[0006] With the development of pulverized coal low-temperature dry distillation technology in recent years, technologies such as external heating vertical furnace, solid heat carrier low-temperature rapid pyrolysis technology, and pulverized coal rotary kiln pyrolysis technology have emerged, which are different from the previous method of direct heating of flue gas using indirect heating, the raw gas components produced have more effective combustible components, and the general components of the raw gas are shown in Table 2, in which the nitrogen content is significantly reduced, but there are still problems of low hydrogen-carbon ratio and high carbon dioxide content

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