CN102807234B - Method for protecting catalyst in tower during maintenance of ammonia synthesis tower - Google Patents
Method for protecting catalyst in tower during maintenance of ammonia synthesis tower Download PDFInfo
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- CN102807234B CN102807234B CN201210314717.4A CN201210314717A CN102807234B CN 102807234 B CN102807234 B CN 102807234B CN 201210314717 A CN201210314717 A CN 201210314717A CN 102807234 B CN102807234 B CN 102807234B
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- tower
- nitrogen
- synthetic tower
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Abstract
The invention relates to a method for protecting a catalyst in a tower during maintenance of an ammonia synthesis tower. The method comprises the following steps: closing a synthesis gas valve and performing nitrogen displacement in the synthesis tower; introducing nitrogen into an outlet pipe of the synthesis tower, wherein the nitrogen reversely enters the synthesis tower; opening a top cover of the synthesis tower, placing a nitrogen pipe between an inner barrel and an outer barrel of the synthesis tower, introducing nitrogen, and sealing the top of a down pipe in the tower by a cover plate; after maintaining the top cover of the synthesis tower, removing the nitrogen pipe and the cover plate of the down pipe and fixing the top cover. The method is convenient to operate, simple and effective, avoids contact between the catalyst and the air and protects the catalytic performance of the catalyst.
Description
Technical field
The present invention relates to a kind of guard method of catalyst, be specifically related to the guard method to catalyst when the large flange maintenance of ammonia plant synthetic tower top cover.
Background technology
The reaction unit synthetic tower of ammonia synthesis system, mainly hydrogen and nitrogen are carried out to catalytic synthesis under the existence of separating matchmaker, because the reaction of synthetic ammonia is reversible reaction, and the performance of the easy oxidized and poisoning reduction catalysis of catalyst, so need the strict content of controlling oxygen in synthetic tower and process gas system.In normal production, because this reaction pressure is high, oxygen can not enter in synthetic tower, and this reaction can completely cut off with oxygen, and ammonia synthesis reaction is normal.But in the process of opening the maintenance of the large flange of synthetic tower top cover because synthetic tower internal pressure is lower than normal atmosphere, airborne oxygen just likely enters the danger that makes catalyst poisoning, burning in synthetic tower, if have air to enter in the process of synthetic tower maintenance, the iron of synthetic tower is that oxidizing reaction can occur catalyst chance oxygen, cause catalyst layer temperature to raise, activity decreased, catalyst layer from top to bottom progressively loses katalysis, and may cause catalyst aging, shorten the life-span, also can cause system crystallization serious, blocking pipe, systemic resistance increases, until cannot continue to produce.If air enters too much, can cause catalyst acutely to burn, synthetic tower damages.
So, when the synthetic large flange of tower top cover is overhauled, need to protect the catalyst in synthetic tower, at present general adopt to catalyst first carry out passivation again hyperthermic reduction catalyst is protected.The scheme of first the catalyst in synthetic tower being carried out to passivation when the large flange of maintenance synthetic tower top cover reaches protection catalyst object.After maintenance, again catalyst is carried out to heating reduction, recovering iron is the activity of catalyst.But this method not only holding time is more, give the normal loss that brings time effects and cause productivity effect of producing; Also there will be catalyst passivation not exclusively or in heating reduction because part iron is the phenomenon that catalyst is not reduced, thereby affect the overall activity of catalyst.
Summary of the invention
Object of the present invention will solve above-mentioned deficiency exactly, provides a kind of safety of when synthetic tower overhauls, catalyst being protected and method efficiently, makes synthetic tower when maintenance, not need that catalyst is carried out to passivation-reduction processing and just can protect better the method for catalyst.
In order to achieve the above object, the invention provides a kind of guard method to catalyst in tower while overhauling for ammonia synthesis converter, described method comprises the following steps:
(1) close the valve of synthetic gas, will in synthetic tower, carry out nitrogen replacement;
(2) the import and export pipe of synthetic tower is all accessed to nitrogen;
(3) open the top cover of synthetic tower, between the inside and outside cylinder of synthetic tower, put into nitrogen tube and pass into nitrogen, and the top of downtake in synthetic tower is carried out airtight with cover plate;
(4), after the top cover of synthetic tower maintenance, withdraw nitrogen tube in (3) and the cover plate of downtake, then fixed roof.
In described step (1), the shell of nitrogen by heat exchanger is divided into Liang Ge branch and enters synthetic tower and carry out nitrogen replacement: Yi Ge branch rises to the catalyst frame top of synthetic tower from bottom centre's pipe of synthetic tower; Another one branch rises and is full of the annular space between the inside and outside cylinder of synthetic tower from synthetic tower bottom.
In order to prevent that synthetic tower top cover from opening rear generation chimneyeffect and having air to enter, and then affect the activity of catalyst in frame.In described step (2), by synthetic tower outlet pipe access two-way nitrogen.
In described step (3), nitrogen tube is ring pipe, is interval with production well on ring pipe, and the diameter of production well is 4-6mm.
The preferred version of such scheme is that the nitrogen of described synthetic tower outlet pipe access accesses by showering guilding valve.
The present invention adopts nitrogen to protect catalyst in synthetic tower, prevents the possibility that catalyst contacts with air, and has effectively avoided catalyst to carry out a series of shortcomings that passivation-method of reducing brings.The present invention first stops synthesis system, by bottom centre's pipe of synthetic tower and the annular space between the inside and outside cylinder of synthetic tower, be full of nitrogen again, make nitrogen and be all full of nitrogen in catalyst frame and between inner/outer tube, form a pressure-fired in tower, outside air just can not enter in synthetic tower.In order to prevent the air intrusion at synthetic tower import and export place, in synthetic tower exit, pipe access nitrogen blocks entering of air; Open after the top cover of synthetic tower, between the inside and outside cylinder of synthetic tower, put into and be provided with the annular nitrogen tube of production well and pass into nitrogen, and the downtake mouth of pipe is covered with cover plate, avoided loss because of nitrogen in synthetic tower that catalyst is oxidized and burn may.Then just can overhaul the top cover of synthetic tower, after maintenance, fixedly withdraw again nitrogen tube after upper top cover and downtake cover plate carries out the production of synthetic ammonia.
Beneficial effect of the present invention has:
1, when synthetic tower top cover is keeped in repair, in tower, catalyst, without carrying out Passivation Treatment, will carry out whole nitrogen replacements in synthetic tower, maintains pressure-fired in tower, has avoided air to enter in tower; And block entering of air at synthetic tower import and export place pipe access nitrogen, and then just can open its top cover and overhaul, the catalyst coming out does not come in contact with air owing to being subject to the protection of nitrogen, thereby produces oxidation.
2, the present invention does not need to carry out the heating reduction step of catalyst, has avoided catalyst to occur reduction phenomenon incomplete or appearance caking in the process of reduction, has guaranteed the safety in production of activity and the synthetic ammonia whole system of catalyst.
3, method of the present invention is easy to operate, simply effective, does not need to consider the various situations that occur in the passivation of catalyst and reduction process during maintenance synthetic tower top cover.
4, this invention has continuity and repeatability, and synthetic tower exit pipe is connected to two-way nitrogen and is filled with synthetic tower, and the supply of its nitrogen is continuous, guarantees the completely isolated of catalyst and air.
Accompanying drawing explanation
Below in conjunction with the drawings and specific embodiments, the present invention is further detailed explanation.
Fig. 1 is device and the nitrogen circulation schematic diagram in the inventive method;
Fig. 2 is synthetic tower vertical view.
In figure: 1-heat exchanger, 2-synthetic tower, 21-urceolus, 22-inner core, 23-downtake, 3-top cover, 4-1-the first showering guilding valve, 4-2-the second showering guilding valve, 5-interchanger, 6-preheater, 7-inlet pipe, 8-outlet pipe.
Embodiment
Embodiment mono-:
A kind ofly the guard method of catalyst in tower is comprised the following steps while overhauling for ammonia synthesis converter:
(1) close synthetic gas valve, will in synthetic tower, carry out nitrogen replacement, the shell of nitrogen by heat exchanger is divided into Liang Ge branch and enters synthetic tower and carry out nitrogen replacement: Yi Ge branch rises to the catalyst frame top of synthetic tower from bottom centre's pipe of synthetic tower; Another one branch rises and is full of the annular space between the inside and outside cylinder of synthetic tower from synthetic tower bottom;
(2) the import and export pipe of synthetic tower is all accessed to nitrogen; Wherein the outlet pipe of synthetic tower is by two showering guilding valve access two-way nitrogen;
(3) open the top cover of synthetic tower, between the inside and outside cylinder of synthetic tower, put into and be interval with the annular nitrogen tube that diameter is 5mm production well, the spacing between production well is 200mm; Nitrogen tube passes into nitrogen, and the top of downtake in synthetic tower is carried out airtight with cover plate;
(4), after the top cover of synthetic tower maintenance, withdraw nitrogen tube in (3) and the cover plate of downtake, more fixing upper top cover.
The present invention first stops synthesis system, by bottom centre's pipe of synthetic tower and the annular space between the inside and outside cylinder of synthetic tower, be full of nitrogen again, make nitrogen all be full of nitrogen to catalyst frame top and synthetic tower high-temperature inner barrel periphery, in tower, form a pressure-fired, outside air just can not enter in synthetic tower.In order to prevent the air intrusion in synthetic tower exit, at synthetic tower outlet pipe access nitrogen, block entering of air; Open after the top cover of synthetic tower, between the inside and outside cylinder of synthetic tower, put into and be provided with the annular nitrogen tube of production well and pass into nitrogen, avoided making catalyst carry out the possibility of oxidizing fire because of the loss of nitrogen in synthetic tower.Then just can overhaul the top cover of synthetic tower, after the rear fixedly upper top cover of maintenance, carry out the production of synthetic ammonia.
When the present invention keeps in repair synthetic tower top cover, in tower, catalyst, without carrying out Passivation Treatment, maintains pressure-fired in tower by carrying out in synthetic tower after whole nitrogen replacements, avoids air to enter in tower; And block entering of air at the import and export pipe access nitrogen of synthetic tower, the supply that makes nitrogen is continuous, guarantees the completely isolated of catalyst and air.Then just can open its top cover and overhaul, the catalyst coming out does not come in contact and produces oxidation with air owing to being subject to the protection of nitrogen.The present invention does not need to carry out the heating reduction step of catalyst, has avoided catalyst to occur reduction phenomenon incomplete or appearance caking in the process of reduction, has guaranteed the safety in production of activity and the synthetic ammonia whole system of catalyst.
Embodiment bis-:
With reference to Fig. 1, figure and device structure schematic diagram, guard method of the present invention is further described:
Close synthetic gas valve, will in synthetic tower 2, carry out nitrogen replacement, the shell of nitrogen by heat exchanger 1 is divided into Liang Ge branch and enters synthetic tower 2 and carry out nitrogen replacement: Yi Ge branch rises to the catalyst frame top of synthetic tower from bottom centre's pipe of synthetic tower 2; Another one branch rises and is full of the annular space between synthetic tower inner core 22, urceolus 21 from synthetic tower bottom; The inlet pipe of synthetic tower 7, outlet pipe 8 are all accessed to nitrogen; Wherein the outlet pipe 8 of synthetic tower is by being located at the first showering guilding valve 4-1 between synthetic tower 2 and interchanger 5, and the second showering guilding valve 4-2 access two-way nitrogen of preheater 6 rear ends; Open the top cover 3 of synthetic tower 2, between the inner core 22 of synthetic tower, urceolus 21, put into and be interval with the annular nitrogen tube that diameter is 6mm production well, the spacing between production well is 200mm; Nitrogen tube passes into nitrogen, and the top of the interior downtake 23 of synthetic tower 2 is carried out airtight with cover plate; After top cover 3 maintenance of synthetic tower 2, withdraw the cover plate on nitrogen tube and downtake, more fixing upper top cover 3.
Above described in be only that the preferred embodiment of the present invention is described; not scope of the present invention is limited; design under spiritual prerequisite not departing from the present invention; various distortion and improvement that the common engineering technical personnel in this area make technical solution of the present invention, all should fall in the definite protection domain of claims of the present invention.
Claims (4)
1. the guard method to catalyst in tower while overhauling for ammonia synthesis converter, is characterized in that: described method comprises the following steps:
(1) close the valve of synthetic gas, the shell by nitrogen by heat exchanger is divided into Liang Ge branch and enters and in synthetic tower, carry out nitrogen replacement: Yi Ge branch rises to the catalyst frame top of synthetic tower from bottom centre's pipe of synthetic tower; Another one branch rises and is full of the annular space between the inside and outside cylinder of synthetic tower from synthetic tower bottom;
(2) the import and export pipe of synthetic tower is all accessed to nitrogen;
(3) open the top cover of synthetic tower, between the inside and outside cylinder of synthetic tower, put into annular nitrogen tube and pass into nitrogen, on described ring pipe, be interval with production well; And the top of downtake in synthetic tower is carried out airtight with cover plate;
(4), after the top cover of synthetic tower maintenance, withdraw nitrogen tube in (3) and the cover plate of downtake, then fixed roof.
2. a kind of guard method to catalyst in tower while overhauling for ammonia synthesis converter according to claim 1, is characterized in that: in described step (2), by synthetic tower outlet pipe access two-way nitrogen.
3. a kind of guard method to catalyst in tower while overhauling for ammonia synthesis converter according to claim 1, is characterized in that: the production well diameter in described step (3) in nitrogen tube is 4-6mm.
4. any guard method to catalyst in tower while overhauling for ammonia synthesis converter according to claim 1 and 2, is characterized in that: the nitrogen of described synthetic tower outlet pipe access accesses by showering guilding valve.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210314717.4A CN102807234B (en) | 2012-08-30 | 2012-08-30 | Method for protecting catalyst in tower during maintenance of ammonia synthesis tower |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210314717.4A CN102807234B (en) | 2012-08-30 | 2012-08-30 | Method for protecting catalyst in tower during maintenance of ammonia synthesis tower |
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| CN102807234A CN102807234A (en) | 2012-12-05 |
| CN102807234B true CN102807234B (en) | 2014-12-10 |
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| CN201210314717.4A Expired - Fee Related CN102807234B (en) | 2012-08-30 | 2012-08-30 | Method for protecting catalyst in tower during maintenance of ammonia synthesis tower |
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Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102101644A (en) * | 2010-12-20 | 2011-06-22 | 昆明理工大学 | Method for preparing ammonia synthesis gas from iron alloy smoke |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5820817B2 (en) * | 2010-12-07 | 2015-11-24 | 国立大学法人東京工業大学 | Ammonia synthesis catalyst and ammonia synthesis method |
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Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102101644A (en) * | 2010-12-20 | 2011-06-22 | 昆明理工大学 | Method for preparing ammonia synthesis gas from iron alloy smoke |
Non-Patent Citations (3)
| Title |
|---|
| "氨合成塔与废热锅炉连接管焊缝裂纹的现场修复";王钰玮 等;《压力容器》;20010930;第18卷;第372-374页 * |
| 崔宗照."浅谈合成氨触媒的升温还原".《化工之友》.1995,(第3期),第44-46页. * |
| 王钰玮 等."氨合成塔与废热锅炉连接管焊缝裂纹的现场修复".《压力容器》.2001,第18卷第372-374页. * |
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Effective date of registration: 20210413 Address after: 234000 No. 157, Xichang Road, Suzhou, Anhui Patentee after: WANBEI COAL-ELECTRICITY GROUP Co.,Ltd. Address before: 232038 Anhui Province, Huainan city tianjia'an District Quanshan Patentee before: ANHUI HUAIHUA Co.,Ltd. |
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Granted publication date: 20141210 Termination date: 20210830 |