A process device and method for recovering cold energy from lng produced from coke oven gas

Abstract

The invention discloses a process device and a process method for recovering cold energy from LNG prepared from coke oven gas. The device comprises a dehydrogenation tower, an LNG reflux pump, a coaxial compression expander, a liquid separation tank and a heat exchanger, wherein the heat exchanger is sequentially connected with the dehydrogenation tower, the LNG reflux pump, the coaxial compression expander and the liquid separation tank; and a feed port at the top of the dehydrogenation tower is sequentially connected with the heat exchanger and the LNG reflux pump. The process device and the process method disclosed by the invention have the beneficial effects that hydrogen-rich gas cold energy recycling and expander refrigeration are adopted to recycle the cold energy from a device for LNG prepared from the coke oven gas; part of the cold energy is provided for LNG and a mixed refrigerant by use of low-temperature hydrogen-rich gas removed from the coke oven gas; and meanwhile, reheated hydrogen-rich gas enters the heat exchanger again by throttling expansion to provide the cold energy until the hydrogen-rich gas enters the coaxial compression expander at normal temperature. The process device is simple in flow; the corresponding heat exchanger is only additionally provided with two flow channels, and the simplicity in operation is realized, power consumption of a refrigerant compressor unit can be greatly saved; and the hydrogen-rich gas can be flexibly disposed according to the downstream demand.

Description

technical field [0001] The invention relates to a process device and method for recovering cold energy from a coke oven gas LNG device in the coke oven gas LNG production process, especially for the small and medium-sized nitrogen-enriched gas LNG production device and method. Background technique [0002] Coke oven gas is a by-product of coking. Its main components are methane, hydrogen and nitrogen. It is a good chemical raw material and high calorific value fuel. The large-scale direct discharge of coke oven gas not only troubles enterprises and the government, but also wastes a lot of available resources. In order to solve the problem of comprehensive utilization of coke oven gas in small and medium-sized enterprises, the effective components of methane and hydrogen in coke oven gas are used as two resources. It is an inevitable choice to realize the comprehensive utilization of coke oven gas and the diversification of downstream products, fundamentally manage the envir...

AI Technical Summary

Problems solved by technology

Especially in the case of producing LNG from coke oven gas containing a large amount of hydrogen and nitrogen, the non-methane components in the process gas carry a large amount of low-temperature energy. reduce

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