CN106316805B - Formaldehyde production process for maintaining high mixing degree of raw materials by using static mixer - Google Patents
Formaldehyde production process for maintaining high mixing degree of raw materials by using static mixer Download PDFInfo
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- CN106316805B CN106316805B CN201510387996.0A CN201510387996A CN106316805B CN 106316805 B CN106316805 B CN 106316805B CN 201510387996 A CN201510387996 A CN 201510387996A CN 106316805 B CN106316805 B CN 106316805B
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- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C45/00—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds
- C07C45/27—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation
- C07C45/32—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation with molecular oxygen
- C07C45/37—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation with molecular oxygen of >C—O—functional groups to >C=O groups
- C07C45/38—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation with molecular oxygen of >C—O—functional groups to >C=O groups being a primary hydroxyl group
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C45/00—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds
- C07C45/78—Separation; Purification; Stabilisation; Use of additives
- C07C45/81—Separation; Purification; Stabilisation; Use of additives by change in the physical state, e.g. crystallisation
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Abstract
The invention relates to a formaldehyde production process, in particular to a formaldehyde production process for maintaining high mixing degree of raw materials by using a static mixer. The formaldehyde production process fully utilizes the absorption heat generated in the formaldehyde production process, and simultaneously, the waste water generated in the amino molding compound production process is mixed with the raw material liquid methanol and then is conveyed to the evaporator, so that the influence of low-quality heat generated by the absorption tower on the scaling of a heat exchanger is solved, and the problem of waste water treatment in the amino molding compound production process is also solved.
Description
Technical Field
The invention relates to a formaldehyde production process, in particular to a formaldehyde production process which is applied to the production of amino molding plastic and maintains high mixing degree of raw materials by using a static mixer.
Background
The amino molding plastic is commonly called as electrical jade powder, and is widely used in the industries of electronics, electric appliances, automobiles, machinery, daily utensils and the like because the raw materials are low in price, the production process is simple, the environment is protected, the solution is easy to solve, the product is bright in color, smooth in appearance, odorless and tasteless, and has the advantages of self-extinguishing and arc resistance, heat resistance, flame retardance, low smoke, stable size, good electrical insulation, easiness in coloring and the like. At present, 2 production process routes of amino molding plastic exist, one route is a wet route adopted by most countries, and the other route is a BUSS method created by Swiss BUSS company. The wet process includes the first generation of resin with urea and formaldehyde in reactor, the subsequent mixing of stuffing and other supplementary material with resin in kneading machine, drying in drier, crushing, ball milling and sieving to obtain the final product. The BUSS process has only 2 steps, namely, urea and formaldehyde react in a reaction kettle, other fillers and resin are added in a high-speed mixer, and granular products are directly obtained after high-speed mixing and dehydration.
In the production process of amino molding compound, a large amount of amino molding compound wastewater containing a large amount of formaldehyde is inevitably generated, so that how to effectively treat the amino molding compound wastewater to enable the amino molding compound wastewater to meet the national environmental protection requirements is always the focus of attention of the domestic and foreign amino molding compound production industry. In the prior art, the 'application and popularization of high-concentration formaldehyde wastewater treatment technology' describes the treatment of amino mold wastewater in more detail, but the treatment steps are complicated, so that the amino mold wastewater is not applied in a large scale.
The production method of formaldehyde which is one of the main raw materials of the amino molding plastic comprises a silver method and an iron-molybdenum method, and the former method has the advantages of low investment, low power consumption and low production cost and occupies a leading position in the domestic formaldehyde production. The basic process for producing formaldehyde by the silver method comprises the following steps: the methanol gas, the air and the ingredient steam are mixed and then enter a reactor, and the mixed gas reacts under the action of a silver catalyst to generate formaldehyde gas. Because formaldehyde is easily decomposed at high temperature and the yield of formaldehyde is reduced, a gas product needs to be cooled as soon as possible, the cooled formaldehyde gas enters an absorption tower and is absorbed by absorption liquid to generate heat, in order to ensure the continuous production, the part of low-quality heat needs to be removed, the heat exchanger is easy to scale due to heat exchange with circulating water in the heat exchanger, and the load of a water cooling tower is increased, so that the low-quality heat is difficult to be reasonably recycled.
In addition, in the prior art, self-generated steam is mostly used as ingredient steam to enter an oxidizer together with air and methanol gas to remove heat generated by oxidation so as to control the temperature of the silver layer, so that a large part of the self-generated steam is used by the self and cannot be sold, thereby increasing the production cost of formaldehyde.
The invention aims to overcome the defects in the prior art, and provides a method for creatively mixing the waste water generated in the production process of amino molding compound with the raw material liquid methanol and then conveying the mixture to an evaporator by fully utilizing the low-quality heat generated in the formaldehyde absorption process through optimizing the design so as to overcome the negative influence caused by the low-quality heat, thereby not only solving the influence of the low-quality heat generated by absorption on the scaling of a heat exchanger, but also solving the problem of waste water treatment in the overshoot production of the amino molding compound, and simultaneously reducing the consumption of steam ingredients due to the large amount of water contained in the waste water, so that the method has the advantages of high efficiency, energy conservation, environmental protection, low cost and the like.
Disclosure of Invention
The invention adopts the technical scheme that the formaldehyde production process is applied to the production of amino molding compound, and a static mixer is utilized to maintain the high mixing degree of raw materials, and the production device comprises an evaporator, a reactor, an absorption device and a tail gas treatment device, and is characterized in that low-quality heat generated in an absorption tower is taken as a heat source and is introduced into a heat exchange section of the evaporator to provide energy required by the volatilization of a raw material mixture comprising methanol, wherein the raw material mixture is obtained by mixing amino molding compound wastewater, liquid methanol with the mass concentration of 100 percent and other raw materials through the static mixer, and the mass concentration of the methanol in the raw material mixture is 30-80 percent; the static mixer is provided with a mixed liquid inlet and a mixed liquid outlet which are in a truncated cone shape, a plurality of mixing elements which are in a regular triangular cone shape are uniformly distributed on the inner wall of the static mixer, the diameter ratio of the distance from the inner wall to the tip of the regular triangular cone to the static mixer ranges from 1/2 to 2/3, the cone angle range of the regular triangular cone ranges from 15 degrees to 45 degrees, and a plurality of secondary mixing elements are uniformly distributed on the upper surface of the mixing elements relative to the horizontal plane.
Wherein, the absorption device comprises a first-stage absorption tower and a second-stage absorption tower, wherein the other raw materials can be tail gas generated at the top of the second-stage absorption tower.
Wherein, the heat exchange section equipment is a heat exchanger.
Wherein the heat exchanger is arranged outside the evaporator, and preferably an additional heating device is arranged inside the evaporator.
Wherein, the heat exchanger is arranged at the inner side of the evaporator.
The heat exchange of the heat exchange section is realized by exchanging heat with the absorption liquid at the bottom of the first-stage absorption tower.
The amino mold wastewater mainly comprises water and formaldehyde, wherein the mass concentration range of the formaldehyde is 1-2%.
Wherein, the amino mold wastewater is subjected to filtration and decoloration treatment in advance.
Wherein the secondary mixing elements are selected from regular tetrahedrons, triangular pyramids, cones, curved baffles.
The invention has the beneficial effects that:
1. firstly, the low-quality heat generated by absorption in the absorption tower is used as a formaldehyde evaporation heat source, so that the problem that the low-quality heat is difficult to be effectively utilized is solved, and the method has the advantages of energy conservation, environmental protection and reduction of the production cost of enterprises.
2. Secondly, the amino molding compound wastewater and liquid methanol are mixed and then conveyed to an evaporator, thereby not only solving the influence of low-quality heat generated by absorption on the scaling of a heat exchanger, but also solving the problem of wastewater treatment in the overshoot production of the amino molding compound. On the basis, the condition that excessive formaldehyde gas in the mixed solution affects the generation of the methanol oxidation reaction is avoided by optimizing the mass concentration ratio of the amino molding plastic wastewater to the liquid methanol in the mixed solution.
3. In addition, the physicochemical properties of the liquid methanol and the amino mold wastewater are combined, a specific static mixer is designed by adopting theoretical simulation, and the heating degree of the mixed liquid of the liquid methanol and the amino mold wastewater is ensured, so that the high reaction rate of the formaldehyde oxidation reaction is maintained.
4. Finally, the original amino mold wastewater is reasonably pretreated to be utilized by an evaporator, so that the whole process is rationalized; in addition, because the amino molding compound wastewater contains a large amount of water, the amino molding compound wastewater is added into the evaporator and replaces ingredient steam under the air stripping action, so that a large amount of steam can be saved for sale.
Drawings
The invention is further illustrated with reference to the accompanying drawings and examples:
FIG. 1 is a process flow diagram of the present invention;
FIG. 2 is a static mixer used in the present invention;
in the figure, 1-evaporator, 2-reactor, 3-drum I, 4-first stage absorption tower, 5-second stage absorption tower, 6-tail gas liquid seal tank, 7-tail gas processor, 8-drum II, 9-heat exchanger, 10-condenser, 11-static mixed gas, 12-mixed liquid inlet, 13-mixed liquid outlet, 14-mixing element and 15-secondary mixing element;
a-amino molding compound wastewater, b-liquid methanol, c-air, d-ingredient steam, e-methanol-air-steam-tail gas quaternary mixed gas, f-crude product gas, g-circulating tail gas, h-product, i-tail gas to be treated, j-purified tail gas and k-steam product.
Detailed Description
The invention will be further described with reference to the following drawings and specific embodiments:
the invention will now be described in further detail with reference to the accompanying figures 1, 2 and examples. The drawing is a simplified schematic diagram illustrating only the basic process flow of the present invention in a schematic manner, and thus shows only the constitution related to the present invention.
As shown in FIG. 1, the process flow of the preferred embodiment is as follows: the amino molding compound wastewater a is conveyed into a liquid methanol b conveying pipeline with the mass concentration of 100 percent to realize the primary mixing between the two fluids, and the two fluids are fully mixed by a static mixer 11. The mixed solution enters the evaporator 1 after being heated by the heat exchanger 9, and the mixed solution is mixed with the ingredient steam d from the steam drum I3 and the tail gas from the top of the absorption tower 5 under the stripping action of the air c to form a methanol-air-steam-tail gas quaternary mixed gas e which is conveyed to the reactor 2. In the reactor 2, dehydrogenation oxidation reaction occurs under the action of silver catalyst, methanol is oxidized into formaldehyde, and the heat generated by the exothermic reaction is absorbed by the steam drum I3 to generate steam, so that the steam is introduced into the evaporator 1 as ingredient steam d to be recycled. The crude product gas f leaving the reactor 2 enters a first-stage absorption tower 4 and a second-stage absorption tower 5 in sequence, the formaldehyde gas in the crude product gas f is completely absorbed through the absorption action of the absorption liquid, the absorption liquid absorbing the high-temperature formaldehyde gas exchanges heat with the mixed liquid at a heat exchanger 9 and then is cooled by a condenser 10, part of the absorption liquid continuously returns to the first-stage absorption tower for gas absorption, and the other part of the absorption liquid is conveyed to a corresponding product tank (not shown in the figure) as a product h. Similarly, a part of the tail gas which is not absorbed by the absorption liquid is returned to the evaporator 1 as the recycled tail gas g to be used as the raw material, and the other part of the tail gas is discharged to the air as the tail gas i to be treated after being treated by the tail gas liquid seal tank 6 and the tail gas processor 7 in sequence. Wherein, the heat generated in the tail gas absorbing process of the tail gas processor 7 is used for obtaining high-quality steam through the steam drum II, and the steam can be sold as a product.
Fig. 2 shows a static mixer according to the invention, which static mixer 11 has a mixture inlet 12 and a mixture outlet 13 in the form of a truncated cone, on the inner wall of which a plurality of mixing elements 14 in the form of a right-angled pyramid are distributed, the ratio of the distance from the inner wall to the tip of said right-angled pyramid to the diameter of 2/3 of the static mixer, the angle of the right-angled pyramid being 30 °, and on the upper surface of the mixing elements with respect to the horizontal a plurality of secondary mixing elements, here regular tetrahedrons, being distributed.
The above description is only the best mode for carrying out the invention and is not intended to limit the invention. Any modification, equivalent replacement, or improvement made within the spirit and scope of the present invention should be included in the protection scope of the present invention.
Claims (4)
1. A formaldehyde production process for maintaining high mixing degree of raw materials by using a static mixer is applied to amino molding compound production, and a production device of the process comprises an evaporator, a reactor, an absorption device and a tail gas treatment device, and is characterized in that low-quality heat generated by absorption in an absorption tower is taken as a heat source and is introduced into a heat exchange section of the evaporator to provide energy required by volatilization of a raw material mixture comprising methanol, wherein the raw material mixture is obtained by mixing amino molding compound wastewater, liquid methanol with the mass concentration of 100% and other raw materials through the static mixer, and the mass concentration of the methanol in the raw material mixture is 30% -80%; the static mixer is provided with a mixed liquid inlet and a mixed liquid outlet which are in a truncated cone shape, a plurality of regular triangular cone-shaped mixing elements are uniformly distributed on the inner wall of the static mixer, the diameter ratio of the distance from the inner wall to the tip of the regular triangular cone to the static mixer ranges from 1/2 to 2/3, the cone angle range of the regular triangular cone ranges from 15 degrees to 45 degrees, and a plurality of secondary mixing elements are uniformly distributed on the upper surface of the mixing elements relative to the horizontal plane; the main components of the amino mold wastewater are water and formaldehyde, wherein the mass concentration range of the formaldehyde is 1-2%; the absorption device comprises a first-stage absorption tower and a second-stage absorption tower, wherein the other raw material can be tail gas generated at the top of the second-stage absorption tower; the heat exchange section equipment is a heat exchanger; the heat exchanger is arranged outside the evaporator; the heat exchange of the heat exchange section is realized by exchanging heat with the absorption liquid at the bottom of the first-stage absorption tower; in the reactor, dehydrogenation oxidation reaction is carried out under the action of silver catalyst, methanol is oxidized into formaldehyde, and the heat generated by the exothermic reaction is absorbed by a steam pocket connected with the reactor to generate steam which is used as ingredient steam and introduced into an evaporator for recycling.
2. The process for producing formaldehyde using a static mixer to maintain a high degree of mixing of the raw materials as claimed in claim 1, wherein an additional heating device is provided inside the evaporator.
3. The process for producing formaldehyde using a static mixer to maintain a high degree of mixing of raw materials according to claim 1, wherein the amino mold waste water is subjected to filtration and decolorization in advance.
4. The process for the production of formaldehyde using a static mixer to maintain a high degree of mixing of the raw materials according to claim 1, characterized in that the secondary mixing elements are selected from the group consisting of triangular pyramids, cones, curved baffles.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201510387996.0A CN106316805B (en) | 2015-07-03 | 2015-07-03 | Formaldehyde production process for maintaining high mixing degree of raw materials by using static mixer |
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| CN201510387996.0A CN106316805B (en) | 2015-07-03 | 2015-07-03 | Formaldehyde production process for maintaining high mixing degree of raw materials by using static mixer |
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| CN106316805A CN106316805A (en) | 2017-01-11 |
| CN106316805B true CN106316805B (en) | 2020-03-27 |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1550256A (en) * | 2003-05-08 | 2004-12-01 | ���ữѧ��������˾ | A static mixer |
| CN102633609A (en) * | 2012-04-16 | 2012-08-15 | 常州乔尔塑料有限公司 | Formaldehyde production technology capable of recycling amino plastic waste water and equipment thereof |
| CN103585908A (en) * | 2013-11-20 | 2014-02-19 | 哈尔滨工程大学 | Multistage guide vane static mixer |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS51115592A (en) * | 1975-04-03 | 1976-10-12 | Matsushita Electric Works Ltd | Process of manufacturing aminoplast molding compounds |
| USH1339H (en) * | 1992-06-03 | 1994-07-05 | Blair Leslie M | Aqueous process for recycling acetal polymer and moldings thereof |
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- 2015-07-03 CN CN201510387996.0A patent/CN106316805B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1550256A (en) * | 2003-05-08 | 2004-12-01 | ���ữѧ��������˾ | A static mixer |
| CN102633609A (en) * | 2012-04-16 | 2012-08-15 | 常州乔尔塑料有限公司 | Formaldehyde production technology capable of recycling amino plastic waste water and equipment thereof |
| CN103585908A (en) * | 2013-11-20 | 2014-02-19 | 哈尔滨工程大学 | Multistage guide vane static mixer |
Non-Patent Citations (1)
| Title |
|---|
| 高浓度甲醛废水处理技术的应用和推广;徐富等;《2009年中国甲醛行业协会年会暨国内外技术交流会报告集》;20091231;第20-25页 * |
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