CN111186820A - A kind of high-purity sulfuric acid production process and production system - Google Patents
A kind of high-purity sulfuric acid production process and production system Download PDFInfo
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- CN111186820A CN111186820A CN202010212076.6A CN202010212076A CN111186820A CN 111186820 A CN111186820 A CN 111186820A CN 202010212076 A CN202010212076 A CN 202010212076A CN 111186820 A CN111186820 A CN 111186820A
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- C01B17/00—Sulfur; Compounds thereof
- C01B17/69—Sulfur trioxide; Sulfuric acid
- C01B17/74—Preparation
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Abstract
本发明公开了一种高纯硫酸的生产工艺，包括以下步骤：S1：发烟硫酸导入蒸发器中加热生成三氧化硫气体；S2：三氧化硫气体导入除雾器中与纯化塔中的冷却盘管换热除杂，得冷凝液相和气相三氧化硫，气相三氧化硫经过除雾，得纯化的三氧化硫气体；S3：循环吸收S2所得三氧化硫气体，得硫酸半成品；S4：经气提和缓冲，得高纯硫酸成品；S2中进入纯化塔的三氧化硫气体进料温度为90～110℃，冷却盘管中冷却介质的温度为40～45℃，经S2换热和除雾处理后的三氧化硫气体出料温度为44～50℃。采用冷却盘管凝结三氧化硫气体中含有金属离子或者其他杂质的不凝性气体，纯化三氧化硫气体。
The invention discloses a production process of high-purity sulfuric acid, comprising the following steps: S1: introducing oleum into an evaporator for heating to generate sulfur trioxide gas; S2: introducing the sulfur trioxide gas into a mist eliminator and cooling in a purification tower Coil heat exchange to remove impurities, condensate liquid phase and gas phase sulfur trioxide, and gas phase sulfur trioxide is demisted to obtain purified sulfur trioxide gas; S3: cyclic absorption of sulfur trioxide gas obtained from S2 to obtain semi-finished sulfuric acid; S4: After air stripping and buffering, high-purity sulfuric acid product is obtained; the feed temperature of sulfur trioxide gas entering the purification tower in S2 is 90-110 °C, and the temperature of the cooling medium in the cooling coil is 40-45 °C. The discharge temperature of the sulfur trioxide gas after the defogging treatment is 44-50°C. The cooling coil is used to condense the non-condensable gas containing metal ions or other impurities in the sulfur trioxide gas to purify the sulfur trioxide gas.
Description
Technical Field
The invention relates to the technical field of high-purity sulfuric acid production, in particular to a production process and a production system of high-purity sulfuric acid.
Background
The high-purity sulfuric acid is one of common ultra-clean high-purity microelectronic chemical practical reagents, is mainly applied to cleaning, photoetching and corrosion of silicon wafers and corrosion and cleaning of printed circuit boards, and can effectively remove impurity particles, inorganic residues and carbon deposits on the wafers. The requirements for the processing precision of semiconductors, integrated circuits and the like are gradually increased, and the quality requirements of matched ultra-clean high-purity sulfuric acid products are correspondingly increased.
The production process of high-purity sulfuric acid in the prior art mainly comprises a sulfur trioxide absorption method and a combined membrane method. The sulfur trioxide absorption method is described in CN109336065A, and comprises the following steps: firstly, generating sulfur trioxide by fuming sulfuric acid through an evaporator; secondly, condensing sulfur trioxide to form liquid sulfur trioxide; thirdly, the liquid sulfur trioxide passes through the evaporator again to generate gaseous sulfur trioxide; fourthly, absorbing sulfur trioxide by adopting water or dilute sulfuric acid circulation. The condensation and re-evaporation of sulfur trioxide in the above process act to further purify sulfur trioxide, but the process is complicated in steps and large in energy consumption. In addition, sulfur trioxide gas has extremely strong permeability, the heat exchange medium used for condensing sulfur trioxide is water, and high-temperature gaseous sulfur trioxide penetrates through a heat exchanger to generate violent exothermic reaction with water, so that serious safety problems can be caused.
Disclosure of Invention
One of the objectives of the present invention is to overcome the drawbacks of the prior art and provide a process for producing high purity sulfuric acid, wherein sulfur trioxide is cooled and purified, and the sulfur trioxide is purified by adjusting the feeding and discharging of the purification step and the temperature of the cooling coil.
In order to achieve the technical effects, the technical scheme of the invention is as follows: the production process of the high-purity sulfuric acid is characterized by comprising the following steps of:
s1: introducing oleum into an evaporator to be heated to generate sulfur trioxide gas;
s2: introducing sulfur trioxide gas into a demister to exchange heat with a cooling coil in a purification tower to remove impurities to obtain a condensed liquid phase and gas-phase sulfur trioxide, and demisting the gas-phase sulfur trioxide to obtain purified sulfur trioxide gas;
s3: circularly absorbing sulfur trioxide gas obtained in S2 to obtain a sulfuric acid semi-finished product;
s4: taking dry compressed air as a stripping medium, and stripping the sulfuric acid semi-finished product obtained in the step S3 to obtain a high-purity sulfuric acid finished product;
the feeding temperature of sulfur trioxide gas entering the purification tower in the S2 is 90-110 ℃, the temperature of a cooling medium in the cooling coil is 40-45 ℃, and the discharging temperature of the sulfur trioxide gas after the S2 heat exchange and defogging treatment is 44-50 ℃.
The preferable technical scheme is that the cooling medium in the cooling coil is a sulfuric acid semi-finished product obtained from S3.
The preferable technical scheme is that the temperature of dilute sulfuric acid for circularly absorbing sulfur trioxide gas is 65-70 ℃.
The preferable technical scheme is that the S4 comprises two continuous air stripping steps, and the ratio of the sulfuric acid feeding amount to the air feeding amount in the first air stripping step is (12-17): 1, the ratio of the sulfuric acid feeding amount to the air feeding amount in the secondary air stripping is (3-5): 1.
the invention also aims to provide a high-purity sulfuric acid production system, which comprises a fuming sulfuric acid raw material tank and an evaporator communicated with the fuming sulfuric acid raw material tank, and is characterized in that a gas phase outlet of the evaporator is communicated with the bottom end of a purification tower, a gas phase outlet of the purification tower, a pure water source and a semi-finished product cooling tank are communicated with an absorption tower, and a closed sulfuric acid semi-finished product loop is arranged between the semi-finished product cooling tank and the absorption tower;
and a cooling coil and a demister are arranged in the purification tower, and the demister is positioned above the cooling coil.
The preferable technical scheme is that the cooling device further comprises a low-temperature sulfuric acid storage tank of the semi-finished product cooling tank, and a closed cooling medium loop is arranged between the low-temperature sulfuric acid storage tank and the cooling coil.
The preferable technical scheme is that a heat exchanger is arranged on a pipeline for communicating a discharge port of the low-temperature sulfuric acid storage tank with the cooling coil, or a heating element is arranged in the low-temperature sulfuric acid storage tank.
The preferable technical scheme is that the device further comprises a first air stripping tower and a second air stripping tower, the semi-finished product cooling tank is communicated with the liquid phase feed inlet of the first air stripping tower, the liquid phase discharge outlet of the first air stripping tower is communicated with the liquid phase feed inlet of the second air stripping tower, and the gas phase feed inlets of the first air stripping tower and the second air stripping tower are communicated with a dry compressed air source.
The invention has the advantages and beneficial effects that:
the production process of the high-purity sulfuric acid adopts a cooling coil to condense non-condensable gas containing metal ions or other impurities in sulfur trioxide gas, and purifies the sulfur trioxide gas;
the temperature of the sulfur trioxide gas subjected to cooling treatment is reduced, the permeation rate of the sulfur trioxide gas on the inner wall of a purification and absorption reaction container is reduced, the temperature of an absorption liquid in the cyclic absorption process of the sulfur trioxide can be reduced, and the production safety coefficient is improved;
the sulfur trioxide discharge flow after cooling and demisting treatment is more stable.
Drawings
FIG. 1 is a process scheme of a high purity sulfuric acid production system of examples 1-3;
in the figure: 1. a fuming sulfuric acid raw material tank; 2. an evaporator; 31. a cooling coil; 32. a demister; 4. an absorption tower; 5. a semi-finished product cooling tank; 6. a low temperature sulfuric acid storage tank; 7. a source of pure water; 8. a first stripper column; 9. a second stripper column; 10. a sulfuric acid recovery tank; 11. a buffer tank; 12. a first heat exchanger; 13. a second heat exchanger; 14. and (5) a finished product groove.
Detailed Description
The following further describes embodiments of the present invention with reference to examples. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.
Sulfuric acid semi-finished product as cooling medium
Sulfur trioxide has a very strong permeability, the higher the temperature, the stronger its permeability. Sulfur trioxide infiltration cooling medium aquatic can take place violent exothermic reaction, leads to the temperature in the cooling coil to fluctuate, influences sulfur trioxide's cooling effect, can lead to corresponding safety problem simultaneously. The sulfuric acid semi-finished product obtained by circularly absorbing sulfur trioxide is used as a cooling medium, so that the reaction intensity in the cooling medium is reduced. In order to further ensure production safety, the mass fraction (the ratio of the mass of the solute to the mass of the solution) of the sulfuric acid semifinished product in the cooling coil is preferably 96% or more.
Demister
The demister functions to remove fine liquid droplets entrained in the sulfur trioxide gas. A commonly used sulfur trioxide demister is a wire mesh demister.
Gas stripping
The effect of the stripping is to remove free sulphur dioxide and sulphur trioxide from the sulphuric acid. Preferably, the ratio of the sulfuric acid feed amount to the air feed amount of the primary stripping is larger than the sulfuric acid feed amount to the air feed amount of the secondary stripping. The sulfuric acid feed temperature for the secondary stripping is lowered and the addition of air feed helps to further improve the removal of free sulfur dioxide and sulfur trioxide.
Examples
Examples 1-3 starting with oleum having a sulfur trioxide content of greater than 36%, all based on a high purity sulfuric acid production system as shown in figure 1:
a discharge hole of the fuming sulfuric acid raw material tank 1 is communicated with a liquid-phase feed inlet of an evaporator 2, a top gas-phase outlet of the evaporator 2 is communicated with the bottom end of a purification tower, a gas-phase outlet of the purification tower is communicated with a side-line gas inlet of an absorption tower 4, a pure water source 7 and a semi-finished product cooling tank 5 are both communicated with the top of the absorption tower 4 or the liquid-phase feed inlet at the top end of the side line, a bottom discharge hole of the absorption tower 4 is communicated with the semi-finished product cooling tank 5, and the absorption tower 4 and the semi-finished product cooling;
the purification tower is provided with a cooling coil 31 and a demister 32, the demister 32 is positioned above the cooling coil 31, and a gas-phase feed inlet of the purification tower is positioned below the cooling coil 31.
The semi-finished product cooling tank 5 is communicated with a feed inlet of a low-temperature sulfuric acid storage tank 6, a discharge outlet of the low-temperature sulfuric acid storage tank 6 is communicated with a feed inlet of a cooling coil 31, a discharge outlet of the cooling coil 31 is communicated with the low-temperature sulfuric acid storage tank 6, and the low-temperature sulfuric acid storage tank 6 and the cooling coil 31 form a closed cooling medium loop.
A first heat exchanger 12 is arranged on a pipeline which is communicated with the cooling coil 31 at the discharge hole of the low-temperature sulfuric acid storage tank 6. A second heat exchanger 13 is arranged on a pipeline for communicating the discharge hole of the semi-finished product cooling tank 5 with the absorption tower 4.
The semi-finished product cooling tank 5 is communicated with a feeding hole at the top of a first gas stripping tower 8 or the top end of a side line, the first gas stripping tower 8 is further communicated with a dry compressed air source, a bottom liquid phase discharging hole of the first gas stripping tower 8 is communicated with a feeding hole at the top of a second gas stripping tower 9 or the top end of the side line, a bottom liquid phase discharging hole of the second gas stripping tower 9 is communicated with a buffer tank 11, the buffer tank 11 is communicated with a finished product tank 14, top gas phase discharging holes of the first gas stripping tower 8 and the second gas stripping tower 9 are communicated with a sulfuric acid recovery tank 10, and the sulfuric acid recovery tank 10 is further communicated with a bottom liquid phase discharging hole of an evaporator.
A steam heat exchange pipe is arranged in the evaporator 2 and is communicated with a steam source.
Example 1 the process for producing high purity sulfuric acid employs the following process steps:
s1: pumping fuming sulfuric acid into an evaporator, controlling the inflow speed of the fuming sulfuric acid to be 15000L/h, controlling the temperature of saturated steam in the evaporator to be 140-160 ℃, the pressure to be 0.6MPa, the temperature of the fuming sulfuric acid in the evaporator to be 100-110 ℃, and the pressure of a discharging pipeline of the evaporator to be 0.02 MPa;
s2: the method comprises the following steps that a cooling medium in a cooling coil in a purification tower is a sulfuric acid semi-finished product, the temperature of the cooling medium is 40-43 ℃, the flow rate of the cooling medium is 1m/s, the air inlet temperature of sulfur trioxide of the purification tower is 90-100 ℃, the model of a demister is a PFA (Polytetrafluoroethylene) wire mesh demister, the pressure of a discharge pipeline of the purification tower is 0.02MPa, and the temperature of the sulfur trioxide in the discharge pipeline of the purification tower is 44-47 ℃;
s3: firstly, introducing pure water to absorb sulfur trioxide, reacting the sulfur trioxide with water, raising the temperature of absorption liquid, introducing the absorption liquid into a semi-finished product cooling tank, cooling, introducing the absorption liquid into a low-temperature sulfuric acid storage tank, heating part of a sulfuric acid semi-finished product discharged from the semi-finished product cooling tank through a second heat exchanger, and refluxing the partial sulfuric acid semi-finished product into an absorption tower to circularly absorb the sulfur trioxide;
s4: and (3) stripping to remove sulfur dioxide and sulfur trioxide in the sulfuric acid semi-finished product: pumping the sulfuric acid semi-finished product discharged from the semi-finished product cooling tank into a first stripping tower, introducing dry compressed air into the bottom of the first stripping tower, wherein the air feeding amount is 260kg/h, the sulfuric acid feeding amount is 3700kg/h, pumping the sulfuric acid semi-finished product discharged from the bottom of the first stripping tower into a second stripping tower, introducing dry compressed air into the bottom of the second stripping tower, the air feeding amount is 1000kg/h, and the sulfuric acid feeding amount is 3700 kg/h.
S5: and (4) discharging a liquid phase at the bottom end of the second stripping tower into a buffer tank, and when the mass fraction of sulfuric acid in the buffer tank reaches 96%, discharging to a finished product tank.
Example 2
The embodiment 2 is based on the embodiment 1, and is different in that a cooling medium in a cooling coil in a purification tower is a sulfuric acid semi-finished product, the temperature of the cooling medium is 43-46 ℃, the flow rate of the cooling medium is 1m/s, the gas inlet temperature of sulfur trioxide in the purification tower is 100-110 ℃, the model of a demister is a PFA (Perfluoro ethylene) mesh demister, the pressure of a discharge pipeline of the purification tower is 0.02MPa, and the temperature of the sulfur trioxide in the discharge pipeline of the purification tower is 47-50 ℃.
Example 3
Example 3 is based on example 1 with the difference that only one stripping is carried out with an air feed of 260kg/h and a sulphuric acid feed of 3700 kg/h.
Comparative example
The comparative example is based on the embodiment and is characterized in that the cooling medium in the cooling coil in the purification tower is a sulfuric acid semi-finished product, the temperature of the cooling medium is 50-56 ℃, the flow rate of the cooling medium is 1m/s, the inlet temperature of sulfur trioxide in the purification tower is 90-110 ℃, the model of the demister is PFA (Polytetrafluoroethylene) silk screen demisting, the pressure of a discharge pipeline of the purification tower is 0.02MPa, and the temperature of the sulfur trioxide in the discharge pipeline of the purification tower is 56-62 ℃.
The contents of sulfuric acid and the contents of impurities in the high-purity sulfuric acids obtained in examples 1 to 2 and comparative example were measured, and the results are shown in table 1, in which the sulfuric acid content was analyzed by sodium hydroxide titration method, the metal ion content was measured by inductively coupled plasma mass spectrometry (ICP-MS), the particle impurities were measured by liquid particle analyzer (LCP), and the anion content was measured by liquid Ion Chromatography (IC).
The inlet temperature of the sulfur trioxide of the purifying tower in the comparative example is the same as that in the example 1, the temperature of the cooling medium is higher than that in the example 1, the purified sulfur trioxide is absorbed circularly, the six stages obtained in the comparative example reach the content of the sulfur trioxide similar to that in the example 1, and the content of the metal ion impurities in the sulfuric acid of the comparative example is obviously increased compared with that in the example 1, which shows that the optimization of the temperature of the cooling medium is beneficial to the removal of the metal ion impurities.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the technical principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (8)
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111994879A (en) * | 2020-08-27 | 2020-11-27 | 福建天甫电子材料有限公司 | Preparation process of electronic-grade sulfuric acid |
| CN114275743A (en) * | 2021-12-10 | 2022-04-05 | 湖北兴福电子材料有限公司 | Method for producing high-purity liquid sulfur trioxide for electronic-grade sulfuric acid |
| CN114348972A (en) * | 2021-12-10 | 2022-04-15 | 湖北兴福电子材料有限公司 | Intelligent vaporization and energy recycling method and device for electronic-grade sulfuric acid production |
| CN115448259A (en) * | 2022-07-22 | 2022-12-09 | 江化微(镇江)电子材料有限公司 | Production method of electronic-grade sulfuric acid |
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| JP2000302420A (en) * | 1999-02-15 | 2000-10-31 | Sumitomo Chem Co Ltd | Production method of ultra-high purity sulfuric acid |
| CN101222976A (en) * | 2005-07-14 | 2008-07-16 | 奥图泰有限公司 | Process and plant for the condensation of sulfur trioxide from hot starting gases |
| CN211871381U (en) * | 2020-03-24 | 2020-11-06 | 江阴江化微电子材料股份有限公司 | High-purity sulfuric acid production system |
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2020
- 2020-03-24 CN CN202010212076.6A patent/CN111186820A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000302420A (en) * | 1999-02-15 | 2000-10-31 | Sumitomo Chem Co Ltd | Production method of ultra-high purity sulfuric acid |
| CN101222976A (en) * | 2005-07-14 | 2008-07-16 | 奥图泰有限公司 | Process and plant for the condensation of sulfur trioxide from hot starting gases |
| CN211871381U (en) * | 2020-03-24 | 2020-11-06 | 江阴江化微电子材料股份有限公司 | High-purity sulfuric acid production system |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111994879A (en) * | 2020-08-27 | 2020-11-27 | 福建天甫电子材料有限公司 | Preparation process of electronic-grade sulfuric acid |
| CN114275743A (en) * | 2021-12-10 | 2022-04-05 | 湖北兴福电子材料有限公司 | Method for producing high-purity liquid sulfur trioxide for electronic-grade sulfuric acid |
| CN114348972A (en) * | 2021-12-10 | 2022-04-15 | 湖北兴福电子材料有限公司 | Intelligent vaporization and energy recycling method and device for electronic-grade sulfuric acid production |
| CN115448259A (en) * | 2022-07-22 | 2022-12-09 | 江化微(镇江)电子材料有限公司 | Production method of electronic-grade sulfuric acid |
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