Method and device for combined production of ammonia synthesis gas and SNG by fixed bed crushed coal pressurization and gasification

Abstract

The invention discloses a method for combined production of ammonia synthesis gas and SNG by fixed bed crushed coal pressurization and gasification; raw coal gas is subject to a CO shift step, a low-temperature methanol washing step, and a liquid nitrogen washing step, and then is delivered to an ammonia synthetic step for ammonia synthesis, and a by product of SNG is obtained in the liquid nitrogen washing step. The method omits a complicated methane conversion working section in a traditional synthesis gas production process by using a liquid nitrogen washing device and low-temperature separation technology; inert gas in the synthesis gas is removed, and the methane fraction is separated into liquid methane; finally the synthesis gas is reheated and flows out of a cold box, and reaches the specification for artificial natural gas (SNG) as clean energy. In addition, raw material gas is subject to purification and methane separation, which not only reduces the influence of inert gas in a synthetic loop, reduces waste gas discharge, but also causes no addition of additional mobile equipment, realizes combined production of synthetic ammonia and SNG, and has significant economic and social benefits. The invention also discloses a device used in the method.

Description

Technical field [0001] The present invention relates to the technical field of synthetic ammonia gas purification, in particular to a synthesis gas production of synthetic ammonia using BGL (British Gas-Lurgi) crushed coal slag pressurized gasifier and Lurgi (Lurgi) crushed coal pressurized gasifier The technical field of producing SNG (Substitute Natural Gas) artificial natural gas, in particular, relates to the use of cryogenic liquid nitrogen as an absorbent to remove CO, Ar, and CH4 from the mixed gas, and refine the separated methane fraction into SNG in the process (Substitute Natural Gas) Fixed-bed crushed coal pressurized coal gasification of artificial natural gas products to produce ammonia synthesis gas and SNG co-production method and device, the method and device are suitable for the purification of synthesis gas (containing hydrogen, carbon monoxide, nitrogen, methane, argon) New low-energy low-temperature liquid nitrogen scrubbing (gas removal) and SNG co-producti...

AI Technical Summary

Problems solved by technology

This process has the following disadvantages: 1. The process consumes a lot of energy and wastes resources; 2. The change of the CH4 fraction from the liquid nitrogen washing section affects the methane conversion section; 3. The process is long and highly coupled, which affects the stability, safety, and reliability of the factory. Long-term reliable operation; 4. Low methane recovery rate, low concentration of methane in the methane fraction, and small calorific value; 5. Single product

With the development of society, the advancement of science and technology, and the enhancement of human awareness of environmental protection, SNG has attracted much attention as a clean energy source in recent years, and there are also many patents that mention BGL or Lurgi gasifiers to produce SNG. These patents are only Just produce SNG, does not break the single issue of final product of BGL or Lurgi gasifier

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