System of utilizing liquid nitrogen wash to produce syngas for synthetic ammonia and LNG

Abstract

Disclosed is a system of utilizing liquid nitrogen wash to produce syngas for synthetic ammonia and LNG. The system comprises a first heat exchanger, a second heat exchanger, a dehydrogenation tower, a liquid nitrogen wash tower, a methane tower, a nitrogen refrigerating system and a medium voltage nitrogen inlet pipe, wherein the medium voltage nitrogen inlet pipe is connected to a medium voltage nitrogen gas source, the medium voltage nitrogen inlet pipe is connected to the liquid nitrogen wash tower after passing the first heat exchanger, the second heat exchanger and a third heat exchanger, the medium voltage nitrogen inlet pipe is communicated with a first pipeline through a first inlet pipe, a communication point between the first inlet pipe and the first pipeline is located between a nitrogen compressor unit and the first heat exchanger, and the first inlet pipe is provided with a first valve. According to the system of utilizing liquid nitrogen wash to produce syngas for synthetic ammonia and LNG, qualified syngas for synthetic ammonia is produced, and an LNG product with a high additional value is obtained at the same time; in addition, when a synthesis ammonia system stops, stable operation of the system can be guaranteed under the situation that a raw material of ammonia synthesis is not produced.

Description

technical field [0001] The invention relates to the field of purification treatment of synthetic ammonia raw material gas, in particular to a system for preparing synthetic ammonia raw material gas and LNG by washing with liquid nitrogen. Background technique [0002] The raw material gas required for the synthetic ammonia process includes nitrogen and hydrogen, and the ratio of nitrogen to hydrogen is about 3:1. If the raw material gas for synthetic ammonia contains liquefied natural gas and carbon monoxide, it will cause poisoning of the catalyst for synthetic ammonia. Therefore, when obtaining the raw material gas for synthetic ammonia, not only the nitrogen must be controlled Hydrogen ratio, but also to control the harmful medium in the raw gas. [0003] Coke oven gas is rich in methane, carbon monoxide, hydrogen, and nitrogen. When coke oven gas is used as raw material gas for ammonia synthesis, methane and carbon monoxide components in coke oven gas must be removed. M...

AI Technical Summary

Problems solved by technology

In actual production, the synthetic ammonia system and the liquid nitrogen washing system are connected by pipelines. When the structurally complex ammonia system is shut down for maintenance or other reasons, the liquid nitrogen washing system also has to be shut down, which brings a lot of unnecessary losses, especially for cold boxes. It takes a lot of time and energy to start after shutdown. In the existing technology, there is no liquid nitrogen washing system to ensure the stable operation of the system when the ammonia system is shut down.

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