A system for parallel co-production of lpg by low-temperature dry distillation of coal gas to natural gas

Abstract

A system for low-temperature dry distillation of coal gas to natural gas and co-production of LPG, including low-temperature dry distillation polygeneration unit, purification unit, liquefaction separation unit, methanation unit and pressure swing adsorption unit, and fine desulfurization unit through cross-line and transformer The system is connected to the pressure adsorption unit; before the methanation reaction, the system first uses the low-temperature carbonization cogeneration, purification, and liquefaction separation process to directly pressurize and liquefy the propane, butane and higher hydrocarbons in the low-temperature carbonization gas to prepare the product LPG. The carbon utilization rate is improved, the life of the methanation catalyst is extended, and the load of the subsequent methanation section is reduced; at the same time, the by-product hydrogen of this process solves the demand for high-purity hydrogen when the methanation catalyst is reduced; it realizes the high efficiency of low-rank coal Hierarchical utilization, simple process flow, low energy consumption, and strong operability.

Description

technical field [0001] The invention belongs to the technical field of natural gas, in particular to a system for producing natural gas by low-temperature dry distillation coal gas and co-producing LPG. 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 coal low-temperature dry distillation co-production technology, using dry distillation gas with low calorific value, transforming it into environmentally friendly natural gas, while rich in coal tar and semi-coke, not only realizes the comprehensive utilization of coal resources, but also It alleviates the relative shortage of oil and gas resources in my country, and is in ...

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Problems solved by technology

[0003] The methane content in the gas produced by the low-temperature carbonization of coal is low, and the calorific value of the gas is low. The process cost of purifying methane directly from the gas is high, and the energy utilization rate is low, which is not conducive to industrial scale-up; Lots of H 2 At the same time, it also produces valuable resources such as higher value-added higher hydrocarbons. Usually, these higher hydrocarbons cannot be effectively used due to their relatively small content, but are directly discharged as exhaust gas or lit as "sky lanterns", which not only causes waste of resources , and does not meet the clean utilization route of coal

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