CN102502700B - Method for replacing catalyst of synthesis system - Google Patents

Abstract

The invention belongs to the technical field of ammonia synthesls and relates to a method for replacing a catalyst of a synthesis system, which comprises the following steps: shutting down the synthesis system and closing an introduction air valve; utilizing previous synthesis recycle gas to cool down the catalyst to 250DEG C; shutting down a circulating machine and releasing pressure of the system; after releasing the pressure, introducing carbon dioxide gas into the synthesis system through a pre-converter air discharging opening of the synthesis system; starting the circulating machine and utilizing the carbon dioxide gas to carry out gas displacement of the system; and meanwhile, continuing to cool down the catalyst; and after a catalyst dismounting standard is met, shutting down the circulating machine, and replacing the catalyst according to a conventional method. The method provided by the invention has high operability, is easy to realize, and saves maintenance time.

Description

A kind of synthesis system changes the method for catalyst

Technical field

The invention belongs to synthetic ammonia technical field, particularly relate to synthesis system in a kind of ammonia synthesis process and change the method for catalyst.

Background technology

What the synthesis system in the past in ammonia synthesis process changed catalyst is hydrogen and nitrogen gas, this method is not replaced system comprehensively, catalyst just just carries out removal with after hydrogen and nitrogen gas cooling, but when drawing off, occurring that some reasons cause unavoidably can not removal smoothly, remove overlong time, catalyst temperature rises, and then causes damage to a certain degree to synthesis system internals, and system will carry out getting angry, maintenance also needs again to replace, affect repair schedule, incur loss through delay and produce.

Summary of the invention

The object of this invention is to provide a kind of method that synthesis system changes catalyst, it is long that solution synthesis system changes the catalyst time, and the fragile problem of system internals, after using method of the present invention simultaneously, directly can also to get angry inspection to synthesis system, improve maintenance efficiency.

For achieving the above object, synthesis system of the present invention changes the method for catalyst, and step is as follows:

1), synthesis system stop, close import air valve;

2), ON cycle machine, utilize original synthetic cyclic gas to lower the temperature to catalyst, temperature will to 250 DEG C, stop circulator;

3), pressure release is carried out to synthesis system;

4), by drain before synthesis system tower to synthesis system transport of carbon dioxide gas;

5), ON cycle machine, utilize carbon dioxide to carry out gas displacement to synthesis system, simultaneously to catalyst continue cooling;

6), when detecting catalyst temperature be down to less than 100 DEG C, and when the carbon dioxide content of gas reaches more than 90% in synthesis system, stop circulator;

7) replacing of catalyst, is carried out according to a conventional method.

Method of the present invention is adopted to utilize carbonic acid gas to replace synthesis system; catalyst surface can be oxidized after carbonic acid gas runs into synthetic catalyst; making catalyst run into air at short notice can not oxidation heat liberation in a large number; internals are played a protective role; in addition because carbonic acid gas is replaced synthesis system; so system is got angry, maintenance need not carry out gas displacement again, directly can to get angry maintenance to system, ensure that maintenance safety.

Embodiment

Synthesis system of the present invention changes the method for catalyst, and step is as follows:

1), synthesis system stop, close import air valve;

2), ON cycle machine, utilize original synthetic cyclic gas to lower the temperature to catalyst, after temperature reaches 250 DEG C, stop circulator;

3), to system carry out pressure release, after pressure is unsnatched, open drain valve before tower;

4), by drain before synthesis system tower to synthesis system transport of carbon dioxide gas;

5), ON cycle machine, utilize carbon dioxide to carry out gas displacement to synthesis system, simultaneously to catalyst continue cooling;

6), when detecting catalyst temperature be down to less than 100 DEG C, and when the carbon dioxide content of gas reaches more than 90% in synthesis system, stop circulator;

7) replacing of catalyst, is carried out according to a conventional method;

8), also can to get angry maintenance to synthesis system according to a conventional method.

Claims (1)

1. in ammonia synthesis process, synthesis system changes a catalyst method, it is characterized in that: carry out according to the following steps:

1), synthesis system stop, close import air valve;

2), ON cycle machine, utilize original synthetic cyclic gas to lower the temperature to catalyst, temperature drops to 250 DEG C, stop circulator;

3), pressure release is carried out to synthesis system;

4), by drain before synthesis system tower to synthesis system transport of carbon dioxide gas;

5), ON cycle machine, utilize carbon dioxide to carry out gas displacement to synthesis system, simultaneously to catalyst continue cooling;

6), when detecting catalyst temperature be down to less than 100 DEG C, and when the carbon dioxide content of gas reaches more than 90% in synthesis system, stop circulator;

7) replacing of catalyst, is carried out according to a conventional method.