Full conversion process for high-concentration carbon monoxide

Abstract

The invention relates to a full conversion process for high-concentration carbon monoxide. The process provided by the invention has a short flow, a system is reliable and has small resistance, equipment has a less number and a small occupied area, and is simple to control, and the investment and operating costs are low; a segmented axial-radial shift reactor is used, so that the problems of easyover temperature and difficult temperature control caused by change of load of feed gas having a high content of carbon monoxide in a shift reaction are solved, and compared with an axial shift reactor with stratified air inflow, the segmented axial-radial shift reactor has reduced shift furnace pressure drop and a reduced diameter and height of equipment, so that the equipment investment is greatly reduced; high-pressure saturated steam produced by a controllable isothermal reactor can be superheated, so that an external superheating furnace or combination with other devices for heating is not needed, and the investment and operation difficulty are reduced; improvement of a water-gas ratio of the system can be satisfied by using a method of spraying chilled water and supplementing self-produced saturated steam, high-pressure superheated steam is not need to be introduced from outside of a boundary area, so that energy consumption is reduced; and a temperature-controllable saturated steam generating system with a control valve is arranged, so that the temperature of shift gas can be quickly and effectively adjusted.

Description

technical field [0001] The present invention relates to a whole conversion process for high-concentration carbon monoxide. Background technique [0002] The carbon monoxide conversion device has an extremely important position in the new coal chemical plant. It is the crude synthesis gas from the upstream gasification device, under the action of the catalyst, and according to the requirements of the downstream product for the hydrogen-carbon ratio, all or part of it reacts to generate hydrogen. . Different product requirements have a greater impact on the settings of the transformation process. For the production of hydrogen and synthetic ammonia, it is usually necessary to convert carbon monoxide into hydrogen as much as possible; for the production of oxo gas, such as synthetic methanol, ethylene glycol, synthetic oil, natural gas, etc., the transformation reaction depth is relatively shallow, and it needs to be converted according to the product It is required to adjust...

AI Technical Summary

Problems solved by technology

However, the process has the following problems: ① energy consumption is high, and the added steam must be recovered in the form of condensate through water cooling in the downstream, which increases the investment of low-grade heat recovery

②The process setup is relatively long, usually it is necessary to set up three to four stages of transformation process including the pre-conversion furnace, and the investment is relatively high

④ The catalyst operates under harsh conditions of high temperature and high water-gas ratio, and its service life is short

This process saves steam and avoids the overheating of the second shift furnace, but it also has the following problems: the reaction conditions of the first shift furnace are harsh, which affects the service life of the catalyst, and the steam consumption is still high; The catalyst loading amount of a shift furnace is relatively high, the reaction driving force is large, and it is easy to cause overheating. Therefore, it is necessary to strictly control the ratio of the split gas volume, and the operation is difficult

However, this process also has the following problems: ①The water-gas ratio and carbon monoxide content of the crude synthesis gas produced by the chilled pulverized coal gasification technology are relatively high, and the total gas flow through the first shift furnace can easily cause overheating, so it is not applicable

②Because of the step-by-step quenching method, the reaction depth of the first shift furnace is insufficient compared with the high water-gas ratio process, so it is usually necessary to set up four to five stages of shifting, the process is longer, the investment is higher, and the land occupation is larger

[0007]However, the currently applied isothermal shift technology has the following problems: ①The steam by-produced by the steam drum of the isothermal shift furnace is saturated steam, which cannot produce higher quality superheated steam

The conversion device is a steam surplus device. Usually, the excess steam is used by other users in the whole plant through the steam pipe network, and the temperature of the saturated steam is lowered to produce condensate, which cannot enter the pipe network.

The outlet temperature of the traditional adiabatic shift furnace is relatively high, usually above 400°C, which can be superheated for saturated steam, while the isothermal shift furnace is mostly taken away by the water circulation system due to the reaction heat, and the outlet temperature is only about 300°C, which cannot provide a superheat source. The heating furnace can be set separately or combined with other devices, which increases the complexity of the process and equipment investment

②It is difficult to adjust the temperature of the isothermal transformation furnace

If the isothermal reactor tube leaks, it will cause damage to the catalyst due to water soaking, posing a safety hazard; second, if the pressure of the by-product saturated steam is lower than the pressure of the conversion system, the above-mentioned problem of no place for overheating of the steam will occur. In order to meet the requirements of the water-air ratio of the system, a certain amount of superheated steam needs to be introduced from the outside to make up the system, which increases the investment and operating costs.

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