CO cryogenic separation system using double circulation and separation method thereof

Abstract

The invention discloses a CO cryogenic separation system using double circulation. The CO cryogenic separation system comprises main heat exchangers, a low-temperature separator, a hydrogen stripping tower, a denitriding tower, a demethanizer, a CO compressor and a circulation nitrogen compressor. The invention further discloses a separation method of the CO cryogenic separation system using double circulation. The method includes the processing steps of heat transfer, dehydrogenation, denitrification, demethanation, CO compression cycle, nitrogen compression refrigeration cycle and the like. The CO cryogenic separation system using double circulation and the separation method thereof have the beneficial effects that the double-circulation process of CO compression and nitrogen compression is adopted, and the dual advantages that rectification energy consumption of CO compression cycle is low and compression energy consumption and investment of nitrogen cycle are low are given into play. A heat source of a rectifying tower evaporator and a cold source of a condenser are optimized, and rectification loads can be controlled reliably and stably. Starting and purifying time of the device can further be shortened, and the evacuation amount at the starting stage is decreased. Energy consumption is low, the starting speed is high, the investment can be reduced, and the quantity of emissions is small. The general trend of energy saving and cost reduction are met, and the economic benefits and environmental protection benefits are good.

Description

technical field [0001] The invention relates to the field of cryogenic gas separation, in particular to a double-cycle CO cryogenic separation system and a separation method thereof. Background technique [0002] CO is an important raw material gas for oxo synthesis, and almost all organic chemicals can be prepared from CO. At present, the synthesis gas for producing CO mainly comes from pressurized coal gasification or natural gas / naphtha steam reforming. In addition to CO and hydrogen, the synthesis gas produced by coal gasification also contains a small amount of methane, nitrogen and argon. In view of the very high purity requirements (≥98.5%) of raw material CO in the production of chemical products such as ethylene glycol, acetic acid and dimethyl diamide, it is necessary to mix hydrogen, methane, nitrogen and argon in the synthesis gas remove. Cryogenic separation technology has mature technology, stable operation, large processing capacity, high product purity and ...

AI Technical Summary

Problems solved by technology

[0003] Chinese invention patent CN 100427862 C "method and equipment for producing carbon monoxide by low-temperature distillation" and CN101823709 B "separation of carbon monoxide from a gas mixture containing carbon monoxide" both use pure CO Compression and refrigeration cycles, in view of the low efficiency and high technical requirements of the CO compressor and expander, the energy consumption and investment of this process are relatively large, and the start-up and purification of the device take a long time, and the amount of venting during the start-up stage is large

[0004] Chinese Invention Patent CN 104326472 B "A system and method for producing CO by a nitrogen cycle process" adopts pure nitrogen compression and refrigeration cycle, although the nitrogen compressor and expansion The efficiency of the machine is relatively high and the technology is mature, but when this process is used in occasions that require fine removal of methane and nitrogen, it has the disadvantage of high rectification energy consumption

Images