CN112923780B - Cleaning method of graphite heat exchanger for organic silicon production - Google Patents
Cleaning method of graphite heat exchanger for organic silicon production Download PDFInfo
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- CN112923780B CN112923780B CN202110397388.3A CN202110397388A CN112923780B CN 112923780 B CN112923780 B CN 112923780B CN 202110397388 A CN202110397388 A CN 202110397388A CN 112923780 B CN112923780 B CN 112923780B
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- siloxane
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- cleaning
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 55
- 229910002804 graphite Inorganic materials 0.000 title claims abstract description 55
- 239000010439 graphite Substances 0.000 title claims abstract description 55
- 238000004140 cleaning Methods 0.000 title claims abstract description 41
- 238000000034 method Methods 0.000 title claims abstract description 26
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 13
- 229910052710 silicon Inorganic materials 0.000 title claims abstract description 11
- 239000010703 silicon Substances 0.000 title claims abstract description 11
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 title abstract description 6
- KPUWHANPEXNPJT-UHFFFAOYSA-N disiloxane Chemical class [SiH3]O[SiH3] KPUWHANPEXNPJT-UHFFFAOYSA-N 0.000 claims abstract description 48
- 230000003647 oxidation Effects 0.000 claims abstract description 38
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 38
- QAOWNCQODCNURD-UHFFFAOYSA-N sulfuric acid Substances OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims abstract description 37
- 238000005406 washing Methods 0.000 claims abstract description 35
- 230000001590 oxidative effect Effects 0.000 claims abstract description 30
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims abstract description 26
- 239000002351 wastewater Substances 0.000 claims abstract description 25
- 239000011259 mixed solution Substances 0.000 claims abstract description 23
- 238000009835 boiling Methods 0.000 claims abstract description 13
- 125000004122 cyclic group Chemical group 0.000 claims abstract description 12
- 239000007800 oxidant agent Substances 0.000 claims description 29
- 239000012535 impurity Substances 0.000 claims description 14
- 238000002360 preparation method Methods 0.000 claims description 12
- 239000007788 liquid Substances 0.000 claims description 6
- 238000000746 purification Methods 0.000 claims description 4
- 230000008707 rearrangement Effects 0.000 claims description 4
- 238000010438 heat treatment Methods 0.000 claims description 3
- 239000011347 resin Substances 0.000 abstract description 6
- 229920005989 resin Polymers 0.000 abstract description 6
- 230000007613 environmental effect Effects 0.000 abstract description 2
- 238000006864 oxidative decomposition reaction Methods 0.000 abstract 2
- NEHMKBQYUWJMIP-UHFFFAOYSA-N chloromethane Chemical compound ClC NEHMKBQYUWJMIP-UHFFFAOYSA-N 0.000 description 4
- 239000010865 sewage Substances 0.000 description 4
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- IXCSERBJSXMMFS-UHFFFAOYSA-N hydrogen chloride Substances Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 description 3
- 229910000041 hydrogen chloride Inorganic materials 0.000 description 3
- 239000005416 organic matter Substances 0.000 description 3
- 238000004064 recycling Methods 0.000 description 3
- 238000005903 acid hydrolysis reaction Methods 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000005336 cracking Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 229940050176 methyl chloride Drugs 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- 108010009736 Protein Hydrolysates Proteins 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- NEHMKBQYUWJMIP-NJFSPNSNSA-N chloro(114C)methane Chemical compound [14CH3]Cl NEHMKBQYUWJMIP-NJFSPNSNSA-N 0.000 description 1
- -1 cyclic dimethylsiloxanes Chemical class 0.000 description 1
- 238000003795 desorption Methods 0.000 description 1
- 238000010790 dilution Methods 0.000 description 1
- 239000012895 dilution Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000007770 graphite material Substances 0.000 description 1
- 238000007038 hydrochlorination reaction Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 238000007363 ring formation reaction Methods 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F21/00—Constructions of heat-exchange apparatus characterised by the selection of particular materials
- F28F21/02—Constructions of heat-exchange apparatus characterised by the selection of particular materials of carbon, e.g. graphite
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28G—CLEANING OF INTERNAL OR EXTERNAL SURFACES OF HEAT-EXCHANGE OR HEAT-TRANSFER CONDUITS, e.g. WATER TUBES OR BOILERS
- F28G9/00—Cleaning by flushing or washing, e.g. with chemical solvents
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
Abstract
The invention discloses a cleaning method of a graphite heat exchanger for organic silicon production, and relates to the technical field of graphite heat exchanger cleaning. The cleaning method comprises the following steps: preparing mixed solution of concentrated sulfuric acid and hydrogen peroxide → cyclic oxidation of the mixed solution in the first stage → cyclic oxidation of the mixed solution in the second stage → washing of siloxane with low boiling point → washing of wastewater in the system. The invention utilizes the strong oxidizing property of concentrated sulfuric acid and hydrogen peroxide on different bond type organic matters to carry out oxidative decomposition on the cross-linked siloxane in the graphite heat exchanger, and then utilizes the principle of similar intermiscibility to dissolve the cross-linked siloxane subjected to oxidative decomposition, thereby finally achieving the purpose of removing the cross-linked siloxane. The invention has convenient operation and thorough cleaning, improves the cleaning efficiency by 90 percent, and has no damage or resin falling phenomenon of the graphite heat exchanger after cleaning. Meanwhile, concentrated sulfuric acid and low-boiling-point siloxane can be recycled after treatment, so that the pollution to the environment is reduced, and obvious economic benefits and environmental protection benefits are achieved.
Description
Technical Field
The invention relates to the technical field of cleaning of graphite heat exchangers, in particular to a cleaning method of a graphite heat exchanger for organic silicon production.
Background
In the organic silicon industry, methyl chloride synthesis adopts a methanol hydrochlorination method for preparation, and in order to improve the utilization rate of chlorine, the methyl chloride synthesis adopts concentrated acid hydrolysis and deep desorption processes to produce hydrogen chloride. However, the hydrogen chloride produced in the concentrated acid hydrolysis step carries with it a certain amount of hydrolysates, including cyclic dimethylsiloxanes, linear dimethylsiloxy-alpha, omega-diols and small amounts of impurities. Under the action of pressure and temperature in the production process of methyl chloride, cross-linked siloxane is easy to form to block the subsequent graphite heat exchanger. After parking, the equipment needs to be disassembled, blocked block holes are cleaned block by block, and the cleaning method mainly comprises two modes of chemical cleaning and manual cleaning. The subsequent treatment of the cleaning reagent adopted by the chemical cleaning mode is difficult, and the environmental protection cost is increased. The manual cleaning method has high difficulty and long cleaning time, and reduces the operation efficiency of the system. In addition, the graphite material is brittle, and the manual cleaning process can cause damage to the massive graphite elements, thereby increasing the maintenance cost.
Disclosure of Invention
In order to solve the technical problems, the invention provides a method for cleaning the graphite heat exchanger for organosilicon production, which is rapid, convenient and high in cleaning efficiency.
In order to realize the technical purpose, the invention adopts the following scheme: the cleaning method of the graphite heat exchanger for producing the organic silicon comprises the following steps:
step one, preparing oxidant mixed liquor: preparing concentrated sulfuric acid and hydrogen peroxide into oxidant mixed liquid in a preparation kettle, wherein concentrated sulfuric acid solution is added into the preparation kettle, and then the hydrogen peroxide is added into the concentrated sulfuric acid.
Step two, first stage cyclic oxidation: heating steam is introduced into a jacket of the preparation kettle, the temperature of the oxidant mixed solution is controlled by the steam, the oxidant mixed solution is fed into a graphite heat exchanger by a circulating pump for first-stage circulating oxidation, the circulating oxidant mixed solution returns to the preparation kettle, and part of small molecular organic matter impurities oxidized firstly are brought into the oxidant mixed solution.
Step three, second stage circulating oxidation: after the first-stage circular oxidation is finished, the temperature of the oxidant mixed liquid is continuously raised through the heating steam, the oxidant mixed liquid is fed into the graphite heat exchanger through the circulating pump for second-stage circular oxidation, and the circulating oxidant mixed liquid returns to the preparation kettle. And the sulfuric acid concentration in the oxidant mixed solution is lower than the use index of 80wt% concentration, and then the sulfuric acid mixed solution enters a sulfuric acid concentration system for recycling. The oxidized impurities are mainly micromolecular organic matters, the impurities are mainly divided into two parts, when the sulfuric acid concentration in the oxidant mixed liquor is reduced to 80wt%, part of the impurities enter a sulfuric acid concentration device along with the oxidant mixed liquor, enter a stripping tower after passing through a dilution mixer and a preheater, the gas at the top of the tower is condensed to generate organic wastewater, the impurities exist in the organic wastewater, the organic wastewater enters a sewage treatment system for treatment, and the concentrated sulfuric acid after concentration is recycled.
Step four, washing low-boiling-point siloxane: after the second stage of cyclic oxidation is finished, feeding low-boiling-point siloxane which is placed in the siloxane kettle and has a boiling point of not more than 210 ℃ into the graphite heat exchanger by using a circulating pump, washing the graphite heat exchanger by using the low-boiling-point siloxane, and controlling the temperature of the low-boiling-point siloxane by adding high-temperature steam into a siloxane kettle jacket. The recycled low boiling siloxane is returned to the siloxane kettle. And washing the graphite heat exchanger by using the low-boiling-point siloxane to dissolve the residual micromolecular organic matter impurities, wherein the micromolecular organic matter impurities enter the siloxane kettle along with the low-boiling-point siloxane. When the viscosity of the siloxane reached 10m2After a time/s or more, the siloxane is sent to a rearrangement purification system. The rearrangement purification system mainly adopts a siloxane cracking refining process, siloxane cracking cyclization is changed into low-boiling siloxane again under the strong alkali condition for recycling, and impurities which cannot be cracked are discharged from a sewage outlet.
Step five, washing the wastewater of the system: after the washing of the low-boiling-point siloxane is finished, the HCl-containing wastewater with the acidity less than 3% in a wastewater tank of the system is fed into a graphite heat exchanger through a circulating pump to be washed, the low-boiling-point siloxane washing liquid and trace residual impurities remained in the graphite heat exchanger are washed and replaced, the circulating wastewater is returned to a wastewater tank, and the wastewater enters a sewage treatment system to be treated after reaching the index. And finishing the cleaning of the graphite heat exchanger after the washing of the waste water is finished.
Compared with the prior art, the invention has the beneficial effects that:
(1) the invention has convenient operation and thorough cleaning, improves the cleaning efficiency by 90 percent, and has no damage or resin falling phenomenon of the graphite heat exchanger after cleaning;
(2) after the concentrated sulfuric acid is circularly oxidized, the concentrated sulfuric acid enters a sulfuric acid concentration device for recycling, so that the generation of secondary waste is reduced;
(3) after the low-boiling-point siloxane is washed, the siloxane can be recycled through rearrangement purification, so that secondary waste is reduced;
(4) the washing adopts the waste water washing of the system, and the sewage yield is reduced.
The preferred scheme of the invention is as follows:
the concentration of the concentrated sulfuric acid is more than or equal to 95wt%, and the mass ratio of the concentrated sulfuric acid to the hydrogen peroxide is 1: 1-5%.
The concentration of the concentrated sulfuric acid is more than or equal to 95wt%, and the mass ratio of the concentrated sulfuric acid to the hydrogen peroxide is 1: 3-4%.
The first-stage circulating oxidation temperature (outlet temperature of the graphite heat exchanger) is 20-60 ℃, and the circulating time is 1-4 h.
The first-stage circulating oxidation temperature (outlet temperature of the graphite heat exchanger) is 30-40 ℃, and the circulating time is 1-2 h.
The circulating oxidation temperature (outlet temperature of the graphite heat exchanger) of the second stage is 100-180 ℃, and the circulating time is 1-4 h.
The circulating oxidation temperature (outlet temperature of the graphite heat exchanger) of the second stage is 130-140 ℃, and the circulating time is 1-2 h.
And fourthly, washing the low-boiling-point siloxane at the temperature of 100-150 ℃ for 1-4 h.
And fourthly, washing the low-boiling-point siloxane at the temperature of 100-120 ℃ for 1-2 h.
Drawings
Fig. 1 is a process flow diagram of a cleaning method according to an embodiment of the present invention.
Detailed Description
The present invention will be described in detail with reference to the following embodiments in order to fully understand the objects, features and effects of the invention, but the present invention is not limited thereto.
The embodiment of the invention operates according to the cleaning method of the process flow diagram shown in fig. 1.
Example 1
Concentrated sulfuric acid with the concentration of more than 95wt% and hydrogen peroxide are prepared in a preparation kettle according to the mass ratio of 1:4% to obtain an oxidant mixed solution, and a circulating pump is used for carrying out two-stage circular oxidation operation. The circulating oxidation temperature of the mixed solution of the oxidant in the first stage is 40 ℃, the circulating time is 4 hours, and the circulating oxidation temperature of the mixed solution of the oxidant in the second stage is 150 ℃, and the circulating time is 4 hours. After the two-stage cyclic oxidation is finished, washing the graphite heat exchanger by using low-boiling-point siloxane with the boiling point of less than or equal to 210 ℃, wherein the washing temperature of the low-boiling-point siloxane is 120 ℃, and the cycle time is 4 hours. And washing by using system wastewater after siloxane washing, and finishing the cleaning operation of the graphite heat exchanger after the wastewater of the system is circularly washed for 1 h. The graphite heat exchanger is cleaned up, and the graphite blocks are not damaged or resin falls off.
Example 2
Preparing concentrated sulfuric acid with the concentration of more than 95wt% and hydrogen peroxide in a preparation kettle according to the mass ratio of 1:3% to obtain an oxidant mixed solution, and performing two-stage circular oxidation operation by using a circulating pump. The circulating oxidation temperature of the mixed solution of the oxidant in the first stage is 30 ℃, the circulating time is 3 hours, and the circulating oxidation temperature of the mixed solution of the oxidant in the second stage is 140 ℃, and the circulating time is 3 hours. After the two-stage cyclic oxidation is finished, washing the graphite heat exchanger by using low-boiling-point siloxane with the boiling point of less than or equal to 210 ℃, wherein the washing temperature of the low-boiling-point siloxane is 110 ℃, and the cycle time is 2 hours. And washing by using system wastewater after siloxane washing, and finishing the cleaning operation of the graphite heat exchanger after the wastewater of the system is circularly washed for 1 h. The graphite heat exchanger is cleaned up, and the graphite blocks are not damaged or resin falls off.
Example 3
Preparing concentrated sulfuric acid with the concentration of more than 95wt% and hydrogen peroxide in a preparation kettle according to the mass ratio of 1:3% to obtain an oxidant mixed solution, and performing two-stage circular oxidation operation by using a circulating pump. The circulating oxidation temperature of the mixed solution of the oxidant in the first stage is 30 ℃, the circulating time is 2 hours, the circulating oxidation temperature of the mixed solution of the oxidant in the second stage is 130 ℃, and the circulating time is 2 hours. After the two-stage cyclic oxidation is finished, washing the graphite heat exchanger by using low-boiling-point siloxane with the boiling point of less than or equal to 210 ℃, wherein the washing temperature of the low-boiling-point siloxane is 100 ℃, and the cycle time is 3 hours. And washing by using system wastewater after siloxane washing, and finishing the cleaning operation of the graphite heat exchanger after the wastewater of the system is circularly washed for 0.5 h. The graphite heat exchanger is cleaned up, and the graphite blocks are not damaged or resin falls off.
Example 4
Preparing concentrated sulfuric acid with the concentration of more than 95wt% and hydrogen peroxide in a preparation kettle according to the mass ratio of 1:3% to obtain an oxidant mixed solution, and performing two-stage circular oxidation operation by using a circulating pump. The circulating oxidation temperature of the mixed solution of the oxidant in the first stage is 30 ℃, the circulating time is 1h, the circulating oxidation temperature of the mixed solution of the oxidant in the second stage is 130 ℃, and the circulating time is 1 h. After the two-stage cyclic oxidation is finished, washing the graphite heat exchanger by using low-boiling-point siloxane with the boiling point of less than or equal to 210 ℃, wherein the washing temperature of the low-boiling-point siloxane is 100 ℃, and the cycle time is 1 h. And washing by using system wastewater after siloxane washing, and finishing the cleaning operation of the graphite heat exchanger after the wastewater of the system is circularly washed for 0.5 h. The graphite heat exchanger is cleaned up, and the graphite blocks are not damaged or resin falls off.
Finally, it is noted that: the above-mentioned list is only the preferred embodiment of the present invention, and naturally those skilled in the art can make modifications and variations to the present invention, which should be considered as the protection scope of the present invention provided they are within the scope of the claims of the present invention and their equivalents.
Claims (9)
1. A cleaning method of a graphite heat exchanger for producing organic silicon is characterized by comprising the following steps:
step one, preparing oxidant mixed liquor: preparing oxidant mixed liquid from concentrated sulfuric acid and hydrogen peroxide in a preparation kettle;
step two, first stage cyclic oxidation: heating steam is introduced into a jacket of the preparation kettle, the temperature of the oxidant mixed solution is controlled by the steam, and the oxidant mixed solution is fed into a graphite heat exchanger by a circulating pump for first-stage circular oxidation;
step three, second stage circulating oxidation: after the first-stage circular oxidation is finished, continuously increasing the temperature of the oxidant mixed liquor through steam to perform second-stage circular oxidation, wherein the oxidized impurities are small-molecular organic matters, and part of the impurities are brought into a sulfuric acid concentration system through concentrated sulfuric acid to be treated;
step four, washing low-boiling-point siloxane: after the second stage of cyclic oxidation is finished, feeding the low-boiling-point siloxane with the boiling point of less than or equal to 210 ℃ placed in the siloxane kettle into a graphite heat exchanger by using a circulating pump, washing the graphite heat exchanger, and introducing the other part of oxidized impurities into a rearrangement purification system for treatment; the temperature of the low boiling point siloxane is controlled by adding steam into a siloxane kettle jacket;
step five, washing the wastewater of the system: and (3) feeding HCl-containing wastewater with the acidity of less than 3% in a wastewater tank of the system into the graphite heat exchanger through a circulating pump to wash the wastewater, replacing residual siloxane with low boiling point and residual trace impurities, and finishing the cleaning of the graphite heat exchanger after the wastewater washing is finished.
2. The method for cleaning the graphite heat exchanger for the production of organic silicon as claimed in claim 1, wherein the concentration of concentrated sulfuric acid is not less than 95wt%, and the mass ratio of concentrated sulfuric acid to hydrogen peroxide is 1: 1-5%.
3. The method for cleaning the graphite heat exchanger for the production of organic silicon as claimed in claim 1, wherein the concentration of concentrated sulfuric acid is not less than 95wt%, and the mass ratio of concentrated sulfuric acid to hydrogen peroxide is 1:3% -4%.
4. The cleaning method of the graphite heat exchanger for organosilicon production according to claim 1, wherein the first stage circulating oxidation temperature is 20-60 ℃ and the circulating time is 1-4 h.
5. The cleaning method of the graphite heat exchanger for organosilicon production according to claim 1, wherein the first stage circulating oxidation temperature is 30 ℃ to 40 ℃, and the circulating time is 1h to 2 h.
6. The cleaning method of the graphite heat exchanger for organosilicon production according to claim 1, wherein the temperature of the second stage of cyclic oxidation is 100 ℃ to 180 ℃, and the cycle time is 1h to 4 h.
7. The cleaning method of the graphite heat exchanger for the production of organic silicon, as recited in claim 1, wherein the temperature of the second stage of the cyclic oxidation is 130 ℃ to 140 ℃ and the cycle time is 1h to 2 h.
8. The cleaning method of the graphite heat exchanger for organosilicon production according to claim 1, wherein the washing temperature of the low boiling point siloxane in the step four is 100-150 ℃, and the cycle time is 1-4 h.
9. The method for cleaning the graphite heat exchanger for producing the organic silicon, as recited in claim 1, wherein the washing temperature of the low boiling point siloxane in the fourth step is 100 ℃ to 120 ℃, and the cycle time is 1h to 2 h.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2550392A1 (en) * | 1975-09-02 | 1977-03-03 | Jerome Katz | PROCESS FOR CLEANING, DESIZING AND BLEACHING COTTON CHAIRWARE |
| EP0541002A1 (en) * | 1991-11-08 | 1993-05-12 | Nittetsu Mining Co., Ltd. | Process for recovering sulfuric acid from metal sulfate-containing waste sulfuric acid |
| CN101354542A (en) * | 2007-07-27 | 2009-01-28 | 中芯国际集成电路制造(上海)有限公司 | Method for removing photoresist |
| CN101598717A (en) * | 2008-05-16 | 2009-12-09 | 中国科学院大连化学物理研究所 | Mould the method that legal system is equipped with polydimethylsiloxanechip chip based on the liquid of hydrogel planar micro-patterning |
| CN101649014A (en) * | 2009-09-22 | 2010-02-17 | 西北工业大学 | Method for preparing organosilicon modified styrene-methyl methacrylate copolymer emulsion at room temperature |
| CN207095357U (en) * | 2017-05-25 | 2018-03-13 | 南通星球石墨设备有限公司 | A kind of graphite heat exchanger |
-
2021
- 2021-04-14 CN CN202110397388.3A patent/CN112923780B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2550392A1 (en) * | 1975-09-02 | 1977-03-03 | Jerome Katz | PROCESS FOR CLEANING, DESIZING AND BLEACHING COTTON CHAIRWARE |
| EP0541002A1 (en) * | 1991-11-08 | 1993-05-12 | Nittetsu Mining Co., Ltd. | Process for recovering sulfuric acid from metal sulfate-containing waste sulfuric acid |
| CN101354542A (en) * | 2007-07-27 | 2009-01-28 | 中芯国际集成电路制造(上海)有限公司 | Method for removing photoresist |
| CN101598717A (en) * | 2008-05-16 | 2009-12-09 | 中国科学院大连化学物理研究所 | Mould the method that legal system is equipped with polydimethylsiloxanechip chip based on the liquid of hydrogel planar micro-patterning |
| CN101649014A (en) * | 2009-09-22 | 2010-02-17 | 西北工业大学 | Method for preparing organosilicon modified styrene-methyl methacrylate copolymer emulsion at room temperature |
| CN207095357U (en) * | 2017-05-25 | 2018-03-13 | 南通星球石墨设备有限公司 | A kind of graphite heat exchanger |
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Address after: 063305 Nanpu Development Zone, Hebei, Tangshan City Patentee after: Tangshan Sanyou Silicon Industry Co.,Ltd. Address before: 063305 Nanpu Development Zone, Hebei, Tangshan City Patentee before: SANYOU SILICON INDUSTRY Co.,Ltd. |