CN1054378C - Process for producing melamine and its equipment - Google Patents
Process for producing melamine and its equipment Download PDFInfo
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- CN1054378C CN1054378C CN95104455A CN95104455A CN1054378C CN 1054378 C CN1054378 C CN 1054378C CN 95104455 A CN95104455 A CN 95104455A CN 95104455 A CN95104455 A CN 95104455A CN 1054378 C CN1054378 C CN 1054378C
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Abstract
The present invention relates to a method and a device for preparing melamine. In the method, after urea reacts in a fluidized bed reactor, generated melamine material gas is led in a circular fluidized bed crystallizer after the melamine material gas is treated with dust removal; after the melamine material gas is in contact and mixed with cold melamine solids, melamine crystals are separated; after gas-solid separation, gas is led in the fluidized bed reactor; one part of the melamine solids are used as circular cold materials, the other part of the melamine solids are used as products to be discharged. The present invention has the advantages of compact technological flow, convenient control, small circulation quantity, little equipment investment and low energy consumption.
Description
The present invention relates to field of chemical engineering, particularly the Production of Cyanuramide Processes and apparatus.
Melamine Production is an essential industry process in the chemical industry.Comparatively the popular production technique is as shown in Figure 1 at present.The trimeric cyanamide material gas that comes out from fluidized-bed reactor (1), behind interchanger (2) and strainer tube fly-ash separator (3), enter quenching crystallizer (4), meet with circulation cold air, quenching and separating out with crystal form obtains the finished product by product trapping device (5); The gas of separating out behind the trimeric cyanamide enters urea washing tower (8) again, unreacted urea and a small amount of melamine particles in the flush away gas, make the gas cooling simultaneously, a part recycles as the cold air of crystallizer (4), a part is as fluidized gas influent stream fluidized bed reactor (1), and a part is advanced exhaust gas processing device.The main drawback of this technology is that urea washing tower material requires height, and the gas circulation amount is big, the energy expenditure height.
An object of the present invention is to provide a kind of new production method of trimeric cyanamide, this method has overcome the defective of prior art, and the gas circulation amount reduces greatly, and energy expenditure also significantly descends.
Another object of the present invention provides the used equipment of above-mentioned Production of Cyanuramide method.
Method of the present invention is reacted in fluidized-bed reactor for making urea, after the trimeric cyanamide material gas process fly-ash separator dedusting of coming out, enter the circulating fluidized bed crystallizer, after meeting with cold trimeric cyanamide solid particulate and mixing, the trimeric cyanamide crystallization is separated out, and solid melamine captures melamine particles get off through gas-solid separating device on the material gas and the flow direction, a gas part enters fluidized-bed reactor as fluidized gas, and a part is advanced exhaust gas processing device; The trimeric cyanamide solid of the heat that traps is in circulation bed companion bed, and after the heat-exchanging tube bundle cooling, a part is discharged from discharge gate as product, and a part is made the circulation cold burden and contacted with the material gas that enters the circulating fluidized bed crystallizer.
The characteristics of method of the present invention are to adopt the circulation bed crystallizer with cold solid melamine material gas to be carried out chilling, and the trimeric cyanamide crystallization in the material gas is separated out, rather than with circulation cold air to material gas quenching, method of the present invention has been saved the urea washing device, reduce by about 2/3rds gas circulation amount, greatly reduce energy expenditure, simultaneously owing to be provided with heat-exchanging tube bundle in the circulating fluidized bed companion bed, can reclaim heat, rich producing steam; In the production process, the generation of steam and consumption can reach balance substantially.Method of the present invention is less demanding to the crystallizer material, can use the low alloy steel manufacturing, has saved quenching crystallizer of the prior art and urea washing system, and the urea washing system needs the manufacturing of expensive corrosion resistant stainless steel.As seen the advantage of this technology embodies a concentrated reflection of and saves in facility investment and the conserve energy consumption.
After urea described in the technology of the present invention can melt in a urea melting pot, enter fluidized-bed reactor, spray liquid urea with atomizing nozzle in the reactor, the most handy ligulate atomizing nozzle of atomizing nozzle, referring to another patent CN89207064.9 of the inventor, this nozzle has atomization gas inlet pipe, liquid urea inlet pipe, metallic target, mixing section and shower nozzle, mixing section caliber 50～80mm, long 400～600mm, the nozzle shower nozzle adopts the ligulate throat structure.This nozzle ejection material granularity is little, and logistics is dispersed, and big, the good dispersity of distribution area has improved the transformation efficiency of reaction and the throughput of equipment in fluidized-bed.
Used a kind of particularly preferred circulating fluidized bed crystallizer is provided with main bed housing and the companion's bed housing that communicates on top in the technology of the present invention, the import of material gas is established in main bed housing below, there is gas distributor this import top, establish the secondary air inlet on the lateral housing of sparger, this sparger top is a fluidised bed zones, this top, district is provided with the gas-solid quickly separating device, cyclonic separator is established on companion's bed housing top, heat-exchanging tube bundle is arranged at this separator bottom, establish the product discharge gate on the lateral housing of heat-exchanging tube bundle, on the housing of heat-exchanging tube bundle lower side, establish the recycle stock inclined tube that communicates with main bed housing, the heat-exchanging tube bundle below is companion's bed gas distributor, and the gas feed of companion's bed is established in this sparger below.Wherein the gas-solid quickly separating device is selected another patent CN87205749.6 of the inventor especially for use, this device is coaxial bicone injection of separation device, constitute by conical nozzle and back taper gas cylinder, it is inner to be gas-solid logistics ejection end, be up-thin-low-thick taper, the outside is upper coarse and lower fine taper, and coaxial installation is connected to the exit end of crystallizer master bed.This circulating fluidized bed is by secondary air flow control trimeric cyanamide internal circulating load, by heat exchange quantity of steam control trimeric cyanamide temperature in companion's bed, thereby reach the purpose of temperature of charge in the control fluidized-bed crystallizer, make material gas temperature out remain on 170～180 ℃, both allowed the trimeric cyanamide of the overwhelming majority be able to the crystallization capture, make again that high boiling urea and polymkeric substance are non-crystallizable to get off, guarantee that the trimeric cyanamide that captures is not made with extra care and to reach the quality product requirement.
In technology of the present invention, can be from the gas that the circulating fluidized bed crystallizer comes out through a condenser, gas is further cooled off, with trimeric cyanamide and the unreacted urea that contains in the abundant recovery tail gas, the material that reclaims can add again in the reactor production system and goes, and urea consumption is remained on the lower level.The also available washing device of described condenser replaces.
Thereby, the used equipment of method of the present invention comprises fluidized-bed reactor, fly-ash separator, circulating fluidized bed crystallizer, exhaust gas processing device, turbine type blower fan and connection line thereof, also urea melting pot, condenser can be further comprised, also interchanger can be connected with between reactor and the fly-ash separator.In the reactor also can in establish atomizing nozzle, ligulate atomizing nozzle particularly.Described fly-ash separator is selected the filtration pipe precipitator especially for use.Described circulation bed crystallizer is provided with main bed housing and companion's bed housing, in establish gas-solid quickly separating device, cyclonic separator and replace tubes bundle etc.
Describe a kind of particularly preferred scheme of the present invention below in conjunction with accompanying drawing, above-mentioned and other characteristics of the present invention will be clearer.
Fig. 1 is a kind of existing preparation technology of melamine synoptic diagram.
Fig. 2 is a kind of preparation technology of melamine synoptic diagram of the present invention.
Fig. 3 is the synoptic diagram of a kind of circulating fluidized bed crystallizer used in the technology of the present invention.
Number in the figure 1 is a fluidized-bed reactor, and 2 is interchanger, and 3 is the strainer tube fly-ash separator, 4 is the quenching crystallizer, and 5 is the product trapping device, and 6 is blower fan, 7 is water cooler, and 8 is the urea washing tower, and 9 is urea storage tank, 10 is the urea melting pot, and 11 is urea pump, and 12 is the ornithine cycle pump, 13 is gas-liquid separator, and 14 is the turbine type blower fan, and 15 is circulating fluidized bed crystallizer master bed, 16 are circulating fluidized bed crystallizer companion bed, and 17 is heat-exchanging tube bundle, and 18 is condenser, 19 are companion's bed gas distributor, 20 is the secondary air import, and 21 is material gas gas distributor, and 22 is the product discharge gate, 23 is the recycle stock inclined tube, 24 is the gas-solid quickly separating device, and 25 is cyclonic separator, and 26 is the ligulate atomizing nozzle, 27 is the import of material gas, 28 are the gas feed of companion's bed, and 29 is main bed housing, and 30 are companion's bed housing.
A kind of particularly preferred preparation technology of melamine process of the present invention is that the urea pellet is added urea melting pot (10), heat fused is a liquid therein, add fluidized-bed reactor (1), atomize with atomization gas (tail gas of this technology) through two ligulate atomizing nozzles (26), the trimeric cyanamide material gas that comes out from reactor (1) passes through interchanger (2), behind the strainer tube fly-ash separator (3), enter circulating fluidized bed crystallizer master bed housing (29) through material gas import (27), mix with cold trimeric cyanamide through gas distributor (21) from recycle stock inclined tube (23), after the heat exchange, trimeric cyanamide crystallization in the gas phase is separated out, after Dual-Phrase Distribution of Gas olid separates through gas-solid quickly separating device (24), solid materials enters circulating fluidized bed companion bed housing (30), gas advances cyclonic separator (25), the trimeric cyanamide of carrying secretly in the gas is further captured, gas after the dedusting is after condenser (18) reclaims unreacted urea, a part is sent into fluidized-bed reactor (1) with turbine type blower fan (14), the unnecessary gas of a part carries out vent gas treatment, isolated hot trimeric cyanamide in circulation bed companion bed (16) after heat-exchanging tube bundle (17) heat exchange, a part is discharged from discharge gate (22) as product, all the other trimeric cyanamides as cold conditions enter circulation bed master bed (15) from recycle stock inclined tube (23) and recycle, after a small amount of companion's bed gas enters companion's bed housing by companion's bed gas feed (28), by companion's bed gas distributor (19), make the trimeric cyanamide material in companion's bed be fluidized state, to improve the heat exchange effect in the bed, a spot of secondary air enters main bed housing (29) by secondary air import (20), to improve the Flow of Goods and Materials characteristic in the crystallizer and to control the solid materials internal circulating load.
Claims (9)
1, a kind of method for producing melamine, it is characterized in that making urea in fluidized-bed reactor, to react, after the trimeric cyanamide material gas process fly-ash separator dedusting of coming out, enter the circulating fluidized bed crystallizer, after meeting with cold trimeric cyanamide solid particulate and mixing, the trimeric cyanamide crystallization is separated out, solid melamine is on the material gas and the flow direction, through gas-solid separating device melamine particles is captured, a gas part enters fluidized-bed reactor as fluidized gas, a part is advanced exhaust gas processing device, the trimeric cyanamide solid of the heat that traps in circulation bed companion bed after heat-exchanging tube bundle cools off, a part is discharged from discharge gate as product, and a part is made the circulation cold burden and contacted with the material gas that enters the circulating fluidized bed crystallizer.
2, the method for claim 1, it is characterized in that described urea melts in a urea melting pot after, enter fluidized-bed reactor, spray liquid urea with atomizing nozzle in the reactor.
3, the method for claim 1 is characterized in that regulating the solid melamine internal circulating load with secondary air in described circulating fluidized bed crystallizer.
4, the method for claim 1 is characterized in that making the trimeric cyanamide material in companion's bed be fluidized state with companion's bed gas in described circulating fluidized bed crystallizer.
5, the method for claim 1 is characterized in that controlling material gas temperature out by the heat of regulating the heat-exchanging tube bundle in the circulating fluidized bed crystallizer is 170-180 ℃.
6, the method for claim 1, the gas that it is characterized in that coming out from the circulating fluidized bed crystallizer is through a condenser or washing device.
7, a kind of Production of Cyanuramide equipment is characterized in that comprising fluidized-bed reactor, fly-ash separator, circulating fluidized bed crystallizer, exhaust gas processing device, turbine type blower fan and connection line thereof; Described fly-ash separator links to each other with fluidized-bed reactor, and the circulating fluidized bed crystallizer links to each other with fly-ash separator, and exhaust gas processing device is tied prosperous device with circulating fluidized bed and linked to each other, and the turbine type blower fan links to each other with fluidized-bed reactor with the circulating fluidized bed crystallizer.
8, equipment as claimed in claim 7, it is characterized in that further comprising the urea melting pot that links to each other with fluidized-bed reactor, be connected with interchanger between fluidized-bed reactor and the fly-ash separator, be connected with condenser or washing device between circulating fluidized bed crystallizer and exhaust gas processing device, the turbine type blower fan, establish atomizing nozzle in the fluidized-bed reactor.
9, equipment as claimed in claim 7, it is characterized in that described circulating fluidized bed crystallizer has main bed housing and companion's bed housing, main bed lower housing portion is established the import of material gas, secondary air import, material gas gas distributor, the gas-solid quickly separating device is established on housing top, cyclonic separator, be provided with heat-exchanging tube bundle in companion's bed housing of cyclonic separator below, establish discharge gate, recycle stock inclined tube on the lateral companion's bed of the heat-exchanging tube bundle housing, the heat-exchanging tube bundle below is provided with companion's bed gas distributor, the gas feed of companion's bed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN95104455A CN1054378C (en) | 1995-06-14 | 1995-06-14 | Process for producing melamine and its equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN95104455A CN1054378C (en) | 1995-06-14 | 1995-06-14 | Process for producing melamine and its equipment |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1124236A CN1124236A (en) | 1996-06-12 |
| CN1054378C true CN1054378C (en) | 2000-07-12 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN95104455A Expired - Fee Related CN1054378C (en) | 1995-06-14 | 1995-06-14 | Process for producing melamine and its equipment |
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| CN (1) | CN1054378C (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101113142B (en) * | 2006-07-26 | 2010-09-15 | 山东联合化工股份有限公司 | Process for combined production of melamine and ammonium nitrate |
| CN104235810A (en) * | 2014-09-08 | 2014-12-24 | 山东省舜天化工集团有限公司 | Heat energy recovery device for heat energy produced based on melamine |
| CN105381627B (en) * | 2015-12-14 | 2018-03-06 | 尹明大 | A kind of melamine fluidized-bed crystallizer |
| CN105503758B (en) * | 2016-01-18 | 2019-05-14 | 尹明大 | A kind of Melamine Production system and technique |
| CN109534576A (en) * | 2018-12-25 | 2019-03-29 | 武汉艾科滤膜技术有限公司 | A kind of device of ultrafiltration membrane treatment melamine wastewater |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4465832A (en) * | 1980-03-29 | 1984-08-14 | Stamicarbon B.V. | Melamine preparation |
| US4591644A (en) * | 1983-12-21 | 1986-05-27 | Stamicarbon B.V. | Method and installation for the preparation of melamine |
| US5384404A (en) * | 1993-11-05 | 1995-01-24 | Lee; Jing M. | Process for manufacturing melamine from urea |
-
1995
- 1995-06-14 CN CN95104455A patent/CN1054378C/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4465832A (en) * | 1980-03-29 | 1984-08-14 | Stamicarbon B.V. | Melamine preparation |
| US4591644A (en) * | 1983-12-21 | 1986-05-27 | Stamicarbon B.V. | Method and installation for the preparation of melamine |
| US5384404A (en) * | 1993-11-05 | 1995-01-24 | Lee; Jing M. | Process for manufacturing melamine from urea |
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| Publication number | Publication date |
|---|---|
| CN1124236A (en) | 1996-06-12 |
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