CN102936211A - Method for continuously producing dicyandiamide - Google Patents
Method for continuously producing dicyandiamide Download PDFInfo
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- CN102936211A CN102936211A CN2012104514927A CN201210451492A CN102936211A CN 102936211 A CN102936211 A CN 102936211A CN 2012104514927 A CN2012104514927 A CN 2012104514927A CN 201210451492 A CN201210451492 A CN 201210451492A CN 102936211 A CN102936211 A CN 102936211A
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Abstract
A method for continuously producing dicyandiamide includes the following steps: enabling lime nitrogen, water, cycle hydrogen cyanamide solution and circle dicyandiamide crystallization mother liquid to conduct hydrolysis reaction and CO2 decalcification under normal temperature, and filtering to obtain hydrogen cyanamide solution with target density. PH value of decalcification liquid is 9-9.5. The cycle hydrogen cyanamide solution refers to hydrogen cyanamide solution obtained by conducting decalcification and filtering operation after the lime nitrogen and the dicyandiamide crystallization mother liquid are subjected to hydrolysis reaction in the dicyandiamide production process. The cycle dicyandiamide crystallization mother liquid refers to dicyandiamide crystallization mother liquid obtained by conducting polymerization, crystallization and filtering on hydrogen cyanamide solution with target density in the dicyandiamide production process. The method further includes conducting polymerization, crystallization, filtering and drying on the hydrogen cyanamide solution with target density under the condition that temperature is 68 DEG C-75 DEG C and PH value is 10-10.5 and utilizing the filtered dicyandiamide crystallization mother liquid as the circle dicyandiamide crystallization mother liquid.
Description
Technical field:
The present invention relates to a kind of method of continuous production Dyhard RU 100.
Background technology:
Dyhard RU 100 is a kind of important fine chemical material, can be used for medicine, dyestuff, coating, agricultural chemicals, glass fibre, lubricant and fire retardant etc.The existing Dyhard RU 100 technology of producing adopts lime nitrogen hydrolysis reaction, decalcification and filtration to obtain cyanamide, then carries out cyanamide polymerization, crystallization, filtration, drying and obtains the Dyhard RU 100 product.Dyhard RU 100 saturated aqueous solution content under differing temps is 3.10wt%(20 ℃), 7.24wt%(40 ℃), 15.79wt%(60 ℃), 24.21wt%(75 ℃), Dyhard RU 100 is higher than 80 ℃ in temperature and can resolves into gaseous ammonia and discharge.The concentration of intermediate cyanamide saturated aqueous solution between 15 ℃～25 ℃ is about 44 wt%, in the time of 43 ℃ and water dissolve each other fully.
The lime nitrogen of the cyanamide synthesis unit in the existing Dyhard RU 100 production technique (nitrogen content 20%) is 1:4 with the solid-liquid mass ratio of Dyhard RU 100 crystalline mother solution, the CO that obtains
2The cyanamide filter liquor concentration is about 5wt% after the decalcification, this cyanamide filtrate is carried out Dyhard RU 100 strength of solution that direct polymerization obtains less than 9wt%, far below the saturation concentration 24wt% under the polymerization temperature, the Dyhard RU 100 crystalline rate is about 5%, need very large polymerization and crystallizer, facility investment is higher, increases process cost.In order to improve the concentration of cyanamide filtrate, adopt the mode of underpressure distillation, but the mode of underpressure distillation can obviously increase power consumption and steam consumption, adopt the add-on that improves lime nitrogen, namely increase the solid-liquid mass ratio of lime nitrogen and Dyhard RU 100 crystalline mother solution, although can improve the cyanamide filter liquor concentration, can increase the calcium hydroxide growing amount of hydrolyzed solution, cause pH value to raise, using CO
2Can increase the decalcification temperature of reaction because of liberated heat during decalcification, the rising of pH value and temperature can make cyanamide shift to an earlier date polymerization and generate Dyhard RU 100, Dyhard RU 100 is less because of solubleness, the hot wash-water consumption of calcium carbonate in the time of 20 ℃ that causes filtering in the decalcifying Fluid increases and lime nitrogen raw material consumption, and finally increasing raw material consumption, energy consumption and follow-up crystalline rate increases not obvious.
Summary of the invention:
In view of this, be necessary to provide a kind of method that improves the continuous production Dyhard RU 100 of follow-up Dyhard RU 100 crystalline rate to improve the cyanamide filter liquor concentration.
A kind of method of continuous production Dyhard RU 100 may further comprise the steps:
Lime nitrogen, water, circulation cyanamide solution and circulation Dyhard RU 100 crystalline mother solution are hydrolyzed at normal temperatures and react and CO
2Decalcification, wherein the decalcifying Fluid pH value is 9～9.5, filtration is to obtain to have the cyanamide solution of aimed concn, wherein, circulation cyanamide solution refers to carry out behind lime nitrogen in the Dyhard RU 100 production process and the Dyhard RU 100 crystalline mother solution hydrolysis reaction cyanamide solution that obtains after decalcification and the filter operation, and circulation Dyhard RU 100 crystalline mother solution refers in the Dyhard RU 100 production process to carry out having aimed concn cyanamide solution the Dyhard RU 100 crystalline mother solution of gained after polymerization, crystallization, the filtration;
The cyanamide solution that will have an aimed concn is that 68 ℃～75 ℃, pH value are to carry out polymerization, crystallization, filtration, drying under 10～10.5 the condition to obtain the Dyhard RU 100 product in temperature, and after will filtering the Dyhard RU 100 crystalline mother solution of gained as circulation Dyhard RU 100 crystalline mother solution.
The method of above-mentioned continuous production Dyhard RU 100, employing recycles cyanamide solution and the Dyhard RU 100 crystalline mother solution in the hydrolysis reaction, and then the raising of the concentration of realization cyanamide, also improved simultaneously the Dyhard RU 100 concentration after the polymerization, crystallization does not appear in Dyhard RU 100 under polymerization temperature, make the Dyhard RU 100 crystalline rate can improve 2～4.5 times than the continuous Dyhard RU 100 production technology of present existing disposable adding lime nitrogen, improve one way Dyhard RU 100 yield 12～15%, the method for above-mentioned continuous production Dyhard RU 100 can reduce facility investment and the process cost of the polymerization process in the Dyhard RU 100 production simultaneously.
Description of drawings:
Accompanying drawing 1 is the method flow diagram of the continuous production Dyhard RU 100 of a preferred embodiments.
Among the figure: the method steps S300～S302 that produces continuously Dyhard RU 100.
Embodiment:
Technical scheme provided by the invention is to improve cyanamide filter liquor concentration means to increase substantially follow-up Dyhard RU 100 crystalline rate.
Please referring to Fig. 1, it is the method for the continuous production Dyhard RU 100 of a preferred embodiments, may further comprise the steps:
Step S300, lime nitrogen, water, circulation cyanamide solution and circulation Dyhard RU 100 crystalline mother solution are hydrolyzed at normal temperatures and react and CO
2Decalcification, wherein the decalcifying Fluid pH value is 9～9.5, filtration is to obtain to have the cyanamide solution of aimed concn, wherein, circulation cyanamide solution refers to carry out behind lime nitrogen in the Dyhard RU 100 production process and the Dyhard RU 100 crystalline mother solution hydrolysis reaction cyanamide solution that obtains after decalcification and the filter operation, and circulation Dyhard RU 100 crystalline mother solution refers in the Dyhard RU 100 production process to carry out having aimed concn cyanamide solution the Dyhard RU 100 crystalline mother solution of gained after polymerization, crystallization, the filtration.
Step S302, the cyanamide solution that will have an aimed concn is that 68 ℃～75 ℃, pH value are to carry out polymerization, crystallization, filtration, drying under 10～10.5 the condition to obtain the Dyhard RU 100 product in temperature, and after will filtering the Dyhard RU 100 crystalline mother solution of gained as circulation Dyhard RU 100 crystalline mother solution.
Below provide the method that adopts above-mentioned continuous production Dyhard RU 100 and produce the embodiment of Dyhard RU 100, so that those skilled in the art understand the present invention, the water meter that wherein the bath water amount is taken away with solid in all filter operation among the embodiment, crystalline rate refer to crystallization the Dyhard RU 100 product that goes out and the mass ratio that goes out the Dyhard RU 100 solution of polymeric kettle:
Embodiment 1: 8.2kg/h is contained the reaction that is hydrolyzed at normal temperatures of the lime nitrogen of the circulation Dyhard RU 100 circulation crystallization mother liquor of 3.1wt%, circulation cyanamide filtrate that 27.1kg/h contains 20.67wt%, 7.1kg/h nitrogen content 20wt% and 0.9kg/h water; Pass into the addition of C O to the decalcification tower
2, control decalcifying Fluid PH is 9.3, filters the cyanamide solution of the aimed concn that obtains 37.4kg/h, the weight percent of cyanamide is 20.67wt% in the cyanamide filtrate of wherein circulating; With the cyanamide solution of the 27.1kg/h aimed concn in the cyanamide solution of the aimed concn of 37.4kg/h as circulation cyanamide solution; The cyanamide solution of remaining 10.3kg/h aimed concn is carried out polymerization under 72～75 ℃, behind the polymer fluid heat filtering in continuous cooling crystallizer crystallization 30min, the crystal solution final temp is 20 ℃, obtains the Dyhard RU 100 drying products of 2.1kg/h and the circulation Dyhard RU 100 crystalline mother solution that 8.2kg/h contains 3.1wt% after filtering separation and the drying.
Embodiment 2: the lime nitrogen of 7.1kg/h nitrogen content 20wt% and 36.3kg/h are contained the reaction that is hydrolyzed at normal temperatures of 3.1wt% Dyhard RU 100 circulation crystallization mother liquor; Pass into CO to the decalcification tower
2, control decalcifying Fluid PH is 9.3, filters the calcium carbonate and the cyanamide filtrate that obtain, wherein the weight percent of cyanamide is 5.69wt% in the cyanamide filtrate; Continuation is to the cyanamide filtrate of 5.69wt%, the lime nitrogen that newly adds 7.1kg/h nitrogen content 20wt% be hydrolyzed reaction, logical CO
2Decalcification and filtration, this step repeats 3 times, obtains at last the cyanamide solution that 41.2kg/h contains the aimed concn of 20.69wt%; The cyanamide solution that 41.2kg/h is contained the 20.69wt% aimed concn carries out polymerization under 72～75 ℃, behind the polymer fluid heat filtering in continuous cooling crystallizer crystallization 30min, the crystal solution final temp is 20 ℃, separates the Dyhard RU 100 drying products and the 36.3kg/h that obtain 8.53kg/h and contains 3.1wt% circulation Dyhard RU 100 crystalline mother solution.
Embodiment 3: lime nitrogen and the 36.3kg/h of 7.1kg/h nitrogen content 20wt% are contained the reaction that is hydrolyzed under the 3.1wt% circulation Dyhard RU 100 crystalline mother solution normal temperature, pass into CO to the decalcification tower
2, control decalcifying Fluid PH is 9.2, filters the calcium carbonate and the cyanamide filtrate that obtain, wherein the weight percent of cyanamide is 5.69wt% in the cyanamide filtrate; Continuation is to the cyanamide filtrate of 5.69wt%, the lime nitrogen that newly adds 7.1kg/h nitrogen content 20wt% be hydrolyzed reaction, logical CO
2Decalcification and filtration, this step repeats 4 times, adds at last the cyanamide solution that entry dilutes to obtain to contain the aimed concn of 20.69wt%; The cyanamide solution that will contain the aimed concn of 20.69wt% carries out polymerization under 65～72 ℃, behind the polymer fluid heat filtering in continuous cooling crystallizer crystallization 33min, the crystal solution final temp is 20 ℃, and that separates the Dyhard RU 100 drying products obtain 11.50kg/h and be used for circulation contains 3.1wt% Dyhard RU 100 crystalline mother solution.
Below providing the embodiment that utilizes prior art to produce Dyhard RU 100 compares with the embodiment that provides with the present invention:
The lime nitrogen of 7.1kg/h nitrogen content 20wt% and 36.3kg/h are contained the reaction that is hydrolyzed at normal temperatures of 3.1wt% Dyhard RU 100 circulation crystallization mother liquor, pass into the addition of C O to the decalcification tower
2, control decalcifying Fluid PH is 9.3, then filter and obtain 37.4kg/h and contain 5.69wt% cyanamide filtrate and calcium carbonate, cyanamide filtrate is carried out polymerization under 72～75 ℃, behind the polymer fluid heat filtering in continuous cooling crystallizer crystallization 30min, the crystal solution final temp is 20 ℃, and the Dyhard RU 100 drying products and the 36.3kg/h that obtain 1.88kg/h after filtering separation and the drying contain 3.1wt% Dyhard RU 100 crystalline mother solution for circulation.
The embodiment that prior art is produced Dyhard RU 100 compares with the embodiment 1 that provides with the present invention, can find out: obviously reduce from polymerization unit and the filter plant of polymerization process of the present invention, can reduce investment and process cost; Crystalline rate is 4.1 times of Comparative Examples, and one way Dyhard RU 100 yield improves 13.7%.
The embodiment that prior art is produced Dyhard RU 100 compares with embodiment 2, the embodiment 3 that provides with the present invention, can find out: the higher concentration cyanamide solution that the present invention obtains can obtain the Dyhard RU 100 drying products of about 4 times of amounts in polymerization unit and filter plant operation that size approaches.
Claims (4)
1. method of producing continuously Dyhard RU 100 may further comprise the steps:
Lime nitrogen, water, circulation cyanamide solution and circulation Dyhard RU 100 crystalline mother solution are hydrolyzed at normal temperatures and react and CO
2Decalcification, wherein the decalcifying Fluid pH value is 9～9.5, filtration is to obtain to have the cyanamide solution of aimed concn, wherein, circulation cyanamide solution refers to carry out behind lime nitrogen in the Dyhard RU 100 production process and the Dyhard RU 100 crystalline mother solution hydrolysis reaction cyanamide solution that obtains after decalcification and the filter operation, and circulation Dyhard RU 100 crystalline mother solution refers in the Dyhard RU 100 production process to carry out having aimed concn cyanamide solution the Dyhard RU 100 crystalline mother solution of gained after polymerization, crystallization, the filtration;
The cyanamide solution that will have an aimed concn is that 68 ℃～75 ℃, pH value are to carry out polymerization, crystallization, filtration, drying under 10～10.5 the condition to obtain the Dyhard RU 100 product in temperature, and after will filtering the Dyhard RU 100 crystalline mother solution of gained as circulation Dyhard RU 100 crystalline mother solution.
2. the method for continuous production Dyhard RU 100 according to claim 1 is characterized in that: lime nitrogen, water, circulation cyanamide solution and circulation Dyhard RU 100 crystalline mother solution be hydrolyzed at normal temperatures reaction and CO
2Decalcification, wherein the decalcifying Fluid pH value is 9～9.5, filter take the concrete steps of the cyanamide solution that obtains to have aimed concn as:
8.2kg/h is contained the reaction that is hydrolyzed at normal temperatures of the lime nitrogen of the circulation Dyhard RU 100 circulation crystallization mother liquor of 3.1wt%, circulation cyanamide filtrate that 27.1kg/h contains 20.67wt%, 7.1kg/h nitrogen content 20wt% and 0.9kg/h water;
Pass into CO to the decalcification tower
2, control decalcifying Fluid PH is 9.3, filters the cyanamide solution of the aimed concn that obtains 37.4kg/h, the weight percent of cyanamide is 20.67wt% in the cyanamide filtrate of wherein circulating;
"The cyanamide solution that will have an aimed concn is that 68 ℃～75 ℃, pH value are to carry out polymerization, crystallization, filtration, drying under 10～10.5 the condition to obtain the Dyhard RU 100 product in temperature, and after will filtering the Dyhard RU 100 crystalline mother solution of gained as circulation Dyhard RU 100 crystalline mother solution " concrete steps be:
With the cyanamide solution of the 27.1kg/h aimed concn in the cyanamide solution of the aimed concn of 37.4kg/h as circulation cyanamide solution;
The cyanamide solution of remaining 10.3kg/h aimed concn is carried out polymerization under 72～75 ℃, behind the polymer fluid heat filtering in continuous cooling crystallizer crystallization 30min, the crystal solution final temp is 20 ℃, obtains Dyhard RU 100 drying products and circulation Dyhard RU 100 crystalline mother solution after filtering separation and the drying.
3. the method for continuous production Dyhard RU 100 according to claim 1, it is characterized in that: lime nitrogen, water, circulation cyanamide solution and circulation Dyhard RU 100 crystalline mother solution are hydrolyzed at normal temperatures and react and the CO2 decalcification, wherein the decalcifying Fluid pH value is 9.3, filtration is to obtain to have the cyanamide solution of aimed concn, and this step is specially:
7.1kg/h the lime nitrogen of nitrogen content 20wt% and 36.3kg/h contain the reaction that is hydrolyzed at normal temperatures of 3.1wt% Dyhard RU 100 circulation crystallization mother liquor;
Pass into CO to the decalcification tower
2, control decalcifying Fluid PH is 9.3, filters the calcium carbonate and the cyanamide filtrate that obtain, wherein the weight percent of cyanamide is 5.69wt% in the cyanamide filtrate;
Continuation is to the cyanamide filtrate of 5.69wt%, the lime nitrogen that newly adds 7.1kg/h nitrogen content 20wt% be hydrolyzed reaction, logical CO
2Decalcification and filtration, this step repeats 3 times, obtains at last the cyanamide solution that 41.2kg/h contains the aimed concn of 20.69wt%;
"The cyanamide solution that will have an aimed concn is that 68 ℃～75 ℃, pH value are to carry out polymerization, crystallization, filtration, drying under 10～10.5 the condition to obtain the Dyhard RU 100 product in temperature, and after will filtering the Dyhard RU 100 crystalline mother solution of gained as circulation Dyhard RU 100 crystalline mother solution " concrete steps be:
The cyanamide solution that 41.2kg/h is contained the 20.69wt% aimed concn carries out polymerization under 72～75 ℃, behind the polymer fluid heat filtering in continuous cooling crystallizer crystallization 30min, the crystal solution final temp is 20 ℃, separates to obtain Dyhard RU 100 drying products and circulation Dyhard RU 100 crystalline mother solution.
4. the method for continuous production Dyhard RU 100 according to claim 1 is characterized in that: lime nitrogen, water, circulation cyanamide solution and circulation Dyhard RU 100 crystalline mother solution be hydrolyzed at normal temperatures reaction and CO
2Decalcification, wherein the decalcifying Fluid pH value is 9.2, filters to obtain to have the cyanamide solution of aimed concn, this step is specially:
Lime nitrogen and the 36.3kg/h of 7.1kg/h nitrogen content 20wt% are contained the reaction that is hydrolyzed under the 3.1wt% circulation Dyhard RU 100 crystalline mother solution normal temperature, pass into CO to the decalcification tower
2, control decalcifying Fluid PH is 9.2, filters the calcium carbonate and the cyanamide filtrate that obtain, wherein the weight percent of cyanamide is 5.69wt% in the cyanamide filtrate,
Continuation is to the cyanamide filtrate of 5.69wt%, the lime nitrogen that newly adds 7.1kg/h nitrogen content 20wt% be hydrolyzed reaction, logical CO
2Decalcification and filtration, this step repeats 4 times, adds at last the cyanamide solution that entry dilutes to obtain to contain the aimed concn of 20.69wt%;
"The cyanamide solution that will have an aimed concn is that 68 ℃～75 ℃, pH value are to carry out polymerization, crystallization, filtration, drying under 10～10.5 the condition to obtain the Dyhard RU 100 product in temperature, and after will filtering the Dyhard RU 100 crystalline mother solution of gained as circulation Dyhard RU 100 crystalline mother solution " concrete steps be:
The cyanamide solution that will contain the aimed concn of 20.69wt% carries out polymerization under 65～72 ℃, behind the polymer fluid heat filtering in continuous cooling crystallizer crystallization 33min, the crystal solution final temp is 20 ℃, separates to obtain Dyhard RU 100 drying products and circulation Dyhard RU 100 crystalline mother solution.
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Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103896813A (en) * | 2014-04-10 | 2014-07-02 | 宁夏宝马化工集团有限公司 | High-purity dicyandiamide production process |
| CN103936632A (en) * | 2014-05-05 | 2014-07-23 | 宁夏宝马化工集团有限公司 | Dicyandiamide continuous multistage crystallizing production process |
| CN107162938A (en) * | 2017-05-24 | 2017-09-15 | 贝利特化学股份有限公司 | The dicyandiamide production method of dicyandiamide dreg is filtered with horizontal flame filter press |
| CN111233005A (en) * | 2020-02-13 | 2020-06-05 | 宁夏嘉峰化工有限公司 | Cyanamide freeze concentration method |
| CN112209857A (en) * | 2020-10-29 | 2021-01-12 | 宁夏蓝白黑循环科技有限公司 | Preparation method of dicyandiamide |
| CN113511988A (en) * | 2021-08-20 | 2021-10-19 | 四川金象赛瑞化工股份有限公司 | System and method for preparing dicyandiamide by using urea |
| CN113527144A (en) * | 2021-08-06 | 2021-10-22 | 四川金象赛瑞化工股份有限公司 | Production method of cyanamide |
| US11180371B2 (en) | 2019-04-12 | 2021-11-23 | J. Dustin Hultine | Integrated synthesis of commodity chemicals from waste plastic |
| CN114105827A (en) * | 2022-01-27 | 2022-03-01 | 天津凯莱英医药科技发展有限公司 | System and method for continuously synthesizing dicyandiamide |
| CN115925644A (en) * | 2022-11-21 | 2023-04-07 | 内蒙古欣皓医药科技有限公司 | Method for preparing flame retardant by using amine waste mother liquor |
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Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103896813B (en) * | 2014-04-10 | 2015-09-30 | 宁夏宝马化工集团有限公司 | Dyhard RU 100 production technique |
| CN103896813A (en) * | 2014-04-10 | 2014-07-02 | 宁夏宝马化工集团有限公司 | High-purity dicyandiamide production process |
| CN103936632A (en) * | 2014-05-05 | 2014-07-23 | 宁夏宝马化工集团有限公司 | Dicyandiamide continuous multistage crystallizing production process |
| CN103936632B (en) * | 2014-05-05 | 2015-08-12 | 宁夏宝马化工集团有限公司 | The multistage continuous crystallisation production technique of Dyhard RU 100 |
| CN107162938A (en) * | 2017-05-24 | 2017-09-15 | 贝利特化学股份有限公司 | The dicyandiamide production method of dicyandiamide dreg is filtered with horizontal flame filter press |
| CN107162938B (en) * | 2017-05-24 | 2019-08-16 | 贝利特化学股份有限公司 | With the dicyandiamide production method of horizontal flame filter press filtering dicyandiamide dreg |
| US11180371B2 (en) | 2019-04-12 | 2021-11-23 | J. Dustin Hultine | Integrated synthesis of commodity chemicals from waste plastic |
| CN111233005A (en) * | 2020-02-13 | 2020-06-05 | 宁夏嘉峰化工有限公司 | Cyanamide freeze concentration method |
| CN112209857A (en) * | 2020-10-29 | 2021-01-12 | 宁夏蓝白黑循环科技有限公司 | Preparation method of dicyandiamide |
| CN113527144A (en) * | 2021-08-06 | 2021-10-22 | 四川金象赛瑞化工股份有限公司 | Production method of cyanamide |
| CN113511988A (en) * | 2021-08-20 | 2021-10-19 | 四川金象赛瑞化工股份有限公司 | System and method for preparing dicyandiamide by using urea |
| CN114105827A (en) * | 2022-01-27 | 2022-03-01 | 天津凯莱英医药科技发展有限公司 | System and method for continuously synthesizing dicyandiamide |
| CN115925644A (en) * | 2022-11-21 | 2023-04-07 | 内蒙古欣皓医药科技有限公司 | Method for preparing flame retardant by using amine waste mother liquor |
| CN115925644B (en) * | 2022-11-21 | 2024-06-04 | 内蒙古欣皓医药科技有限公司 | Method for preparing flame retardant by using amine waste mother liquor |
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Application publication date: 20130220 |