CN110981775B - Method for removing ammonia in thiourea feed liquid - Google Patents
Method for removing ammonia in thiourea feed liquid Download PDFInfo
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- CN110981775B CN110981775B CN201911308518.0A CN201911308518A CN110981775B CN 110981775 B CN110981775 B CN 110981775B CN 201911308518 A CN201911308518 A CN 201911308518A CN 110981775 B CN110981775 B CN 110981775B
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- C07—ORGANIC CHEMISTRY
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- C07C335/00—Thioureas, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups
- C07C335/02—Thiourea
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Abstract
The invention provides a method for removing ammonia in thiourea feed liquid, which comprises the following steps: and removing ammonia gas in the thiourea feed liquid by using a degassing membrane, and introducing acid liquor to the outer side of the degassing membrane to absorb the ammonia gas. According to the invention, the thiourea feed liquid is treated by the degassing membrane, in the treatment process, the ammonia gas is directionally moved by utilizing the partial pressure difference of the ammonia gas on two sides of the degassing membrane, the removed ammonia gas is absorbed by the acid liquid on the outer side of the membrane to form ammonium salt, and the generated ammonium salt is treated and taken out as a byproduct. The treatment method does not evaporate water, does not change the solubility of calcium, and does not precipitate calcium salt in the treatment process. The method is suitable for industrial production, can stably and efficiently treat ammonia in thiourea feed liquid, solves the problems of secondary pollution and equipment blockage caused by calcium precipitation in the conventional method, and has great application significance in the field of industrial production of thiourea.
Description
Technical Field
The invention relates to the technical field of chemical production, in particular to a method for removing ammonia in thiourea feed liquid.
Background
Thiourea of formula (NH)2)2CS, with a relative molecular mass of 76.12, white rhombic or needle-like bright crystals. And (4) the material is combustible, has a melting point of 170-180 ℃, and is decomposed at high temperature. It is soluble in cold water and ethanol, and almost insoluble in diethyl ether. At present, water, lime nitrogen (calcium cyanamide) and hydrogen sulfide gas are industrially used as raw materials, absorption synthesis reaction is carried out in a synthesis kettle to prepare suspension containing thiourea, the solution is filtered and purified for many times, cooled and crystallized, crystals are centrifugally spun after solid-liquid separation, and then the finished product is prepared after drying.
In the synthesis reaction process, side reactions also occur while calcium cyanamide reacts with hydrogen sulfide and water, so that part of calcium cyanamide is decomposed to generate ammonia gas, and the generated ammonia gas is dissolved in thiourea feed liquid and is slowly released in each production process to damage the working environment.
The pH value of the thiourea solution is 12-13, and the thiourea solution mainly contains 20-23% of thiourea, 10-30 g/L of calcium hydrosulfide, 0.15% of calcium hydroxide and 1-3% of ammonium radicals. The traditional feed liquid deamination mode is gas stripping and distillation stripping, wherein the gas stripping needs a large amount of purified air and generates a large amount of ammonia-containing waste gas which cannot be treated, so that secondary pollution is caused; the composition of the thiourea feed liquid can find that calcium hydroxide in the thiourea feed liquid is saturated, and a large amount of calcium is precipitated after reaching saturation solubility in the distillation treatment process, so that equipment such as a distillation tower, a heat exchanger and the like is blocked and cannot run.
Disclosure of Invention
In view of the above, the technical problem to be solved by the present invention is to provide a method for removing ammonia from a thiourea feed liquid, so as to achieve efficient deamination of the thiourea feed liquid, ensure no secondary pollution during the deamination process, and solve the problem of calcium precipitation.
In order to solve the technical problems, the invention provides a method for removing ammonia in thiourea feed liquid, which is characterized by comprising the following steps:
and removing ammonia gas in the thiourea feed liquid by using a degassing membrane, and introducing acid liquor to the outer side of the degassing membrane to absorb the ammonia gas.
The invention is preferable that the selected degassing membrane is a polypropylene hollow fiber membrane, the membrane aperture of the degassing membrane is preferably 0.01-0.2 mu m, and the membrane area is preferably 10-50 m2。
In the invention, the temperature of the thiourea solution is preferably 35-60 ℃, and more preferably 45-60 ℃.
The feeding flow rate of the thiourea feed liquid is preferably 0.5 t/h-3.0 t/h, and the flow rate of the acid liquid is preferably 6 t/h-15 t/h.
The acid solution is preferably one or more of sulfuric acid, phosphoric acid, hydrochloric acid, nitric acid, acetic acid and formic acid, and is further preferably sulfuric acid, phosphoric acid or hydrochloric acid.
The concentration of the acid liquor is preferably 10% -40%. The concentration is mass concentration.
The introducing pressure of the acid liquid is preferably 0.08 to 0.15 Mpa.
The invention discloses a device for removing ammonia in thiourea feed liquid, which comprises a feed liquid tank, a feed pump, a degassing membrane, an acid liquid tank and an acid liquid circulating pump which are connected in sequence;
the feed inlet of the degassing membrane is connected with the discharge outlet of the feed liquid pump;
the discharge hole of the degassing membrane is a discharge hole of the treated feed liquid;
and the acid liquor in the acid liquor tank is circularly sent to the outer side of the degassing membrane by an acid liquor circulating pump to absorb ammonia gas.
Specifically, the thiourea feed liquid is stored in a feed liquid tank, a feed pump pumps the thiourea feed liquid into a degassing membrane, ammonia in the thiourea feed liquid is removed by using the degassing membrane, and the treated feed liquid flows out from a discharge hole of the degassing membrane; meanwhile, the acid liquor in the acid liquor tank is circularly sent to the outer side of the degassing membrane by an acid liquor circulating pump to absorb ammonia gas.
The pressure of the acid solution is introduced, namely the pressure of the acid solution inlet.
The detailed process flow diagram of the feed liquid deamination is shown in figure 1.
Compared with the prior art, the invention provides a method for removing ammonia in thiourea feed liquid, which comprises the following steps: and removing ammonia gas in the thiourea feed liquid by using a degassing membrane, and introducing acid liquor to the outer side of the degassing membrane to absorb the ammonia gas. According to the invention, the thiourea feed liquid is treated by the degassing membrane, in the treatment process, the ammonia gas is directionally moved by utilizing the partial pressure difference of the ammonia gas on two sides of the degassing membrane, the removed ammonia gas is absorbed by the acid liquid on the outer side of the membrane to form ammonium salt, and the generated ammonium salt is treated and taken out as a byproduct. The treatment method does not evaporate water, does not change the solubility of calcium, and does not precipitate calcium salt in the treatment process. The method is suitable for industrial production, can stably and efficiently treat ammonia in thiourea feed liquid, solves the problems of secondary pollution and equipment blockage caused by calcium precipitation in the conventional method, and has great application significance in the field of industrial production of thiourea.
Drawings
FIG. 1 is a process flow diagram for removing ammonia from a thiourea feed solution.
Detailed Description
In order to further illustrate the present invention, the following will describe the method for removing ammonia from thiourea solution provided by the present invention in detail with reference to the examples.
Example 1
Selecting a membrane with an area of 15m2And a degassing membrane with a membrane aperture of 0.05 μm, and completing the connection of a feed liquid tank, a feed pump, the degassing membrane, an acid liquid tank, an acid liquid circulating pump and an acid liquid tank (see fig. 1, the same below). Adding 50% phosphoric acid solution into an acid solution tank, starting an acid solution circulating pump, controlling the acid solution inlet pressure to be 0.09Mpa, the acid solution circulating flow to be 6t/h, controlling the temperature of the material liquid to be 50 ℃, starting a material liquid feeding pump to feed the material liquid into a degassing membrane, controlling the feeding flow to be 0.6t/h, keeping the circulating flow of the acid solution, monitoring the pH value of the acid solution to be less than or equal to 2 in the process, continuously feeding the material liquid into the degassing membrane, sampling and detecting the content of free ammonia nitrogen in the material liquid, and recording data in a data table 1.
Example 2
Selecting a membrane with an area of 15m2And a degassing membrane with a membrane aperture of 0.15 mu m, and the connection of a feed liquid tank, a feed pump, the degassing membrane, an acid liquid tank, an acid liquid circulating pump and the acid liquid tank is completed. Adding 50% phosphoric acid solution into an acid solution tank, starting an acid solution circulating pump, controlling the acid solution inlet pressure to be 0.11Mpa, the acid solution circulating flow to be 9t/h, controlling the temperature of the material liquid to be 50 ℃, starting a material liquid feeding pump to feed the material liquid into a degassing membrane, controlling the feeding flow to be 1.0t/h, keeping the circulating flow of the acid solution, monitoring the pH value of the acid solution to be less than or equal to 2 in the process, continuously feeding the material liquid into the degassing membrane, sampling and detecting the content of free ammonia nitrogen in the material liquid, and recording data in a data table 1.
Example 3
Selecting a membrane with the area of 45m2And a degassing membrane with the membrane aperture of 0.1 mu m, and the connection of a feed liquid tank, a feed pump, the degassing membrane, an acid liquid tank, an acid liquid circulating pump and the acid liquid tank is completed. Adding 50% phosphoric acid solution into acid solution tank, starting acid solution circulation pump, controlling acid solution inlet pressure at 0.13Mpa, acid solution circulation flow at 14t/h, controlling feed liquid temperature at 50 deg.C, starting feed liquid feed pump to feed liquid into degassing membrane, controlling feed flow at 3.0t/h, maintaining acid solution circulation flow, monitoring acid solution pH at 2 or below, and continuously feeding into degassing membraneFeed liquid enters the degassing membrane, the content of free ammonia nitrogen in the feed liquid is sampled and detected, and the recorded data are shown in a data table 1.
Example 4
Selecting a membrane with the area of 25m2And a degassing membrane with the membrane aperture of 0.1 mu m, and the connection of a feed liquid tank, a feed pump, the degassing membrane, an acid liquid tank, an acid liquid circulating pump and the acid liquid tank is completed. Adding 50% phosphoric acid solution into an acid solution tank, starting an acid solution circulating pump, controlling the acid solution inlet pressure to be 0.11Mpa, the acid solution circulating flow to be 9.5t/h, controlling the temperature of the material liquid to be 50 ℃, starting a material liquid feeding pump to feed the material liquid into a degassing membrane, controlling the feeding flow to be 1.5t/h, keeping the circulating flow of the acid solution, monitoring the pH value of the acid solution to be less than or equal to 2 in the process, continuously feeding the material liquid into the degassing membrane, sampling and detecting the content of free ammonia nitrogen in the material liquid, and recording data in a data table 1.
Comparative example 1
Selecting a membrane with an area of 15m2And a degassing membrane with a membrane aperture of 0.3 mu m, and the connection of a feed liquid tank, a feed pump, the degassing membrane, an acid liquid tank, an acid liquid circulating pump and the acid liquid tank is completed. Adding 50% phosphoric acid solution into an acid solution tank, starting an acid solution circulating pump, controlling the acid solution inlet pressure to be 0.11Mpa, controlling the acid solution circulating flow to be 9t/h, controlling the temperature of the material liquid to be 50 ℃, starting a material liquid feeding pump to feed the material liquid into a degassing membrane, controlling the feeding flow to be 1.0t/h, keeping the circulating flow of the acid solution, monitoring the pH value of the acid solution to be less than or equal to 2 in the process, continuously feeding the material liquid into the degassing membrane, sampling and detecting the content of free ammonia nitrogen in the material liquid and the content of thiourea in an acid absorption solution, and recording data in a data table 1.
Table 1 feed liquid treatment ammonia nitrogen content detection data table
As is clear from the above examples and comparative examples, the method of the present invention can remove ammonia from a thiourea solution to a large extent.
The above description of the embodiments is only intended to facilitate the understanding of the method of the invention and its core idea. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.
Claims (5)
1. A method for removing ammonia in thiourea feed liquid is characterized by comprising the following steps:
removing ammonia gas in the thiourea feed liquid by using a degassing membrane, and introducing acid liquor to the outer side of the degassing membrane to absorb the ammonia gas;
the degassing membrane is a polypropylene hollow fiber membrane, and the membrane aperture of the degassing membrane is 0.01-0.2 mu m; the membrane area is 10 to 50m2；
The feed flow rate of the thiourea feed liquid is 0.5 t/h-3.0 t/h, and the flow rate of the acid liquid is 6 t/h-15 t/h;
the introducing pressure of the acid liquid is 0.08 MPa-0.15 MPa.
2. The method for removing ammonia in thiourea solution as claimed in claim 1, wherein the temperature of thiourea solution is 35-60 ℃.
3. The method for removing ammonia in thiourea solution as claimed in claim 2, wherein the thiourea solution has a temperature of 45-60 ℃.
4. The method for removing ammonia from thiourea feed liquid according to claim 1, wherein the acid solution is one or more selected from sulfuric acid, phosphoric acid, hydrochloric acid, nitric acid, acetic acid and formic acid.
5. The method for removing ammonia from thiourea feed liquid of claim 4, wherein the acid solution is selected from sulfuric acid, phosphoric acid or hydrochloric acid.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101381127A (en) * | 2008-09-26 | 2009-03-11 | 清华大学 | Method for recovering cyanide and ammonia nitrogen in acrylic nitrile waste water using membrane absorption method |
| CN203545804U (en) * | 2013-04-03 | 2014-04-16 | 江苏夏航环境工程有限公司 | Device for treating ammonia-nitrogen wastewater by utilizing direct contact degassing membrane technology |
| CN107285545A (en) * | 2017-07-25 | 2017-10-24 | 杭州绿色环保技术开发有限公司 | A kind of cadmium ammonia waste water technique of zero discharge of thin-film solar cells production line |
| CN107857395A (en) * | 2017-11-27 | 2018-03-30 | 浙江海盐力源环保科技股份有限公司 | A kind of condensate polishing treatment regenerative wastewater ammonia recovery system |
| CN110104861A (en) * | 2019-05-17 | 2019-08-09 | 苏州久华水处理科技有限公司 | Treatment process of thiourea-containing wastewater |
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- 2019-12-18 CN CN201911308518.0A patent/CN110981775B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101381127A (en) * | 2008-09-26 | 2009-03-11 | 清华大学 | Method for recovering cyanide and ammonia nitrogen in acrylic nitrile waste water using membrane absorption method |
| CN203545804U (en) * | 2013-04-03 | 2014-04-16 | 江苏夏航环境工程有限公司 | Device for treating ammonia-nitrogen wastewater by utilizing direct contact degassing membrane technology |
| CN107285545A (en) * | 2017-07-25 | 2017-10-24 | 杭州绿色环保技术开发有限公司 | A kind of cadmium ammonia waste water technique of zero discharge of thin-film solar cells production line |
| CN107857395A (en) * | 2017-11-27 | 2018-03-30 | 浙江海盐力源环保科技股份有限公司 | A kind of condensate polishing treatment regenerative wastewater ammonia recovery system |
| CN110104861A (en) * | 2019-05-17 | 2019-08-09 | 苏州久华水处理科技有限公司 | Treatment process of thiourea-containing wastewater |
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Address after: 256500 Jingbo Industrial Park, Boxing Economic Development Zone, Binzhou, Shandong, China Patentee after: Yifeng New Material Co.,Ltd. Address before: 256500 Jingbo Industrial Park, Boxing Economic Development Zone, Binzhou, Shandong, China Patentee before: SHANDONG EFIRM BIOCHEMISTRY AND ENVIRONMENTAL PROTECTION Co.,Ltd. |