Control method for waste sulfuric acid purification equipment

Abstract

The invention relates to the technical field of environmental protection, in particular to a control method for waste sulfuric acid purification equipment which comprises a reaction kettle, a heating device, a stirring device, a distilling device, a condensing device, a collecting device and a first control device of the equipment. An air pressure detection device, a sulfuric acid concentration detection device and a temperature detection device are arranged in the reaction kettle; a liquid level height detection device and a second control device used for calculating the liquid level height increasing speed in the collection device and feeding back a signal are arranged in the collection device; the vacuum device works according to signals generated by the air pressure detection device and the sulfuric acid concentration detection device or signals generated by the air pressure detection device, the sulfuric acid concentration detection device and the second control device; the heating device works according to signals generated by the temperature detection device and the sulfuric acid concentration detection device. According to the equipment control method, the vacuum device and the heating device are controlled to work through air pressure, sulfuric acid concentration and collected sulfuric acid height signals, the energy consumption is low, the cost is low, and the bumping probability is reduced.

Description

Technical Field

[0001] The present invention relates to the field of waste sulfuric acid purification, and specifically relates to a control method for equipment used to purify waste sulfuric acid. Background Art

[0002] Due to impurities in calcium carbide, the crude acetylene gas generated by the wet calcium carbide process for producing acetylene contains a large amount of water, as well as sulfur, phosphorus, etc. If it is introduced into downstream devices, it will cause equipment corrosion and catalyst poisoning, and affect the quality of downstream products. Currently, the most commonly used in the acetylene purification process is 98% concentrated sulfuric acid, which uses its strong oxidizing property and dehydration property to remove hydrogen sulfide, phosphine and water in the crude acetylene gas. However, after the concentrated sulfuric acid is recycled for a long time, its concentration continuously decreases, and organic substances, sulfur, phosphorus and other impurities gradually increase. When the sulfuric acid concentration drops below 75%, it can no longer be used and is discharged as three wastes.

[0003] In the prior art, methods such as chemical precipitation, ion exchange, and distillation are usually used to treat industrial waste sulfuric acid. The chemical precipitation method uses chemical reactions to convert metal ions in waste sulfuric acid into insoluble salt precipitates for separation, but this method cannot remove organic substances and will produce a large amount of waste residue. The ion exchange method uses ion exchange resins to adsorb metal ions in waste sulfuric acid, but the resins are expensive and difficult to regenerate. The distillation method uses the different boiling points of sulfuric acid and other impurities to separate and purify by distillation, but traditional distillation equipment has a complex structure, high energy consumption, and high cost.

[0004] CN117401653A discloses a method for deep purification of waste sulfuric acid generated in the semiconductor industry. This method first passes the waste sulfuric acid into a hydrogen peroxide removal system. Under heating conditions, a catalyst is added to promote the decomposition of hydrogen peroxide in the waste sulfuric acid. At the same time, under the synergistic action of the catalyst and hydrogen peroxide, metal impurities in the waste sulfuric acid are promoted to form intermediate oxidation products, which is beneficial to the subsequent resin adsorption and impurity removal process; then the waste sulfuric acid is passed through resin impurity removal, and finally the sulfuric acid after impurity removal is passed into an evaporation and concentration system, and concentrated at 100 - 200°C for 3 - 6 hours to obtain a high-purity sulfuric acid product. However, this method still has problems such as complex equipment structure and high energy consumption.

[0005] CN106744722A discloses a regeneration process for acetylene purification waste sulfuric acid. This process uses acetylene purification waste sulfuric acid as a raw material, and the heat required for the purification cracking reaction is generated by burning fuel in a cracking furnace, so that the acetylene purification waste sulfuric acid undergoes a cracking reaction at high temperature in the cracking furnace, and finally generates high-temperature flue gas containing sulfur dioxide, sulfur trioxide, oxygen, phosphorus pentoxide, carbon dioxide, water vapor, nitrogen, soot, etc. The high-temperature flue gas is processed through processes such as furnace gas cooling, air preheating, closed pickling purification, drying, two-stage conversion, and two-stage absorption to produce qualified finished sulfuric acid. However, this process still has problems such as complex equipment structure, cumbersome processes, and high energy consumption.

[0006] Industrial acetylene purified waste sulfuric acid contains sulfuric acid with a concentration ≥ 70%, contains organic substances, sulfur, phosphorus and other impurities. During the existing industrial acetylene purified waste sulfuric acid distillation and recovery process, it is prone to the phenomenon of violent boiling under the conditions of relatively high temperature and relatively low pressure, resulting in the still remaining organic substances, sulfur, phosphorus and other impurities in the recovered sulfuric acid. Therefore, the existing technology for treating acetylene purified waste sulfuric acid has the following disadvantages: 1. The equipment structure is complex and the process flow is cumbersome, resulting in difficult operation, high equipment cost and high maintenance cost. 2. The energy consumption is relatively high, the operation cost is relatively high, which is not conducive to energy conservation and emission reduction. 3. There is a problem of secondary pollution, generating a large amount of waste residue or waste gas, causing new pollution to the environment. 4. The investment cost is high, which is not conducive to popularization and application. 5. It is prone to the phenomenon of violent boiling, resulting in low purity of the recovered sulfuric acid.

[0007] Based on the above problems, it is necessary to propose a device for purifying industrial acetylene purified waste sulfuric acid with a simple structure, low energy consumption and low cost. Summary of the Invention

[0008] The purpose of the present invention is to overcome the disadvantages of complex equipment, low maintenance cost, high energy consumption, prone to violent boiling and low purity of the recovered sulfuric acid existing in the prior art, and propose a control method for a device for purifying waste sulfuric acid.

[0009] A control method for an apparatus for purifying waste sulfuric acid, wherein the waste sulfuric acid is industrial acetylene purification waste sulfuric acid with a sulfuric acid concentration of ≥70% contained therein. The apparatus is provided with a reaction kettle including a gas pressure detection device, a sulfuric acid concentration detection device, and a temperature detection device; a heating device; a stirring device; a distillation device including a diversion device and a vacuum device for decompressing the inside of the reaction kettle; a condensation device; a collection device including a liquid level height detection device and a first control device of the apparatus. The control method of the apparatus includes the following steps: S1. Add the industrial acetylene purification waste sulfuric acid to be treated into the reaction kettle, heat the acetylene purification waste sulfuric acid in the reaction kettle to 120°C through the heating device, and at the same time, the stirring device stirs the acetylene purification waste sulfuric acid solution in the reaction kettle; S2. Open the distillation device, and the vacuum device decompresses the reaction kettle. Under this condition, perform a distillation operation on the uniformly heated acetylene purification waste sulfuric acid solution. The sulfuric acid vapor distilled by the distillation device is condensed into a liquid through the condensation device and enters the collection device to collect the purified sulfuric acid product. Among them, during the distillation operation, the vacuum device works according to the signals generated by the gas pressure detection device and the sulfuric acid concentration detection device; and the heating device works according to the signals generated by the temperature detection device and the sulfuric acid concentration detection device. When the temperature detection device detects that the temperature of the acetylene purification waste sulfuric acid solution in the reaction kettle is heated to a first temperature by the heating device, the first control device receives the signal from the temperature detection device. The first control device controls the heating device to keep the temperature of the acetylene purification waste sulfuric acid in the reaction kettle at the first temperature. At the same time, the first control device controls the vacuum device to start decompressing the inside of the reaction kettle from normal atmospheric pressure until the sulfuric acid concentration in the acetylene purification waste sulfuric acid in the reaction kettle drops from higher than 50% to 50%; when the sulfuric acid concentration detection device detects that the sulfuric acid concentration in the acetylene purification waste sulfuric acid in the reaction kettle drops to 50%, the first control device receives the signal from the sulfuric acid concentration detection device. The first control device controls the vacuum device to keep the pressure in the reaction kettle at the pressure at this time, and the heating device keeps the temperature in the acetylene purification waste sulfuric acid solution in the reaction kettle at the first temperature.

[0010] Further, the gas pressure detection device is arranged at the top end inside the reaction kettle; the sulfuric acid concentration detection device is arranged on the inner wall of the reaction kettle for detecting the sulfuric acid concentration in the liquid in the reaction kettle; the temperature detection device is arranged at the bottom of the reaction kettle; the heating device is arranged outside the reaction kettle for heating the solution in the reaction kettle; the stirring device is arranged inside the reaction kettle for stirring the solution in the reaction kettle; one end of the diversion device is connected to the reaction kettle, and the other end of the diversion device is connected to the collection device; the condensation device is used for cooling the diversion device; the collection device is also provided with a second control device for calculating the rising speed of the internal liquid level height and feeding back a signal; the vacuum device also works according to the signals generated by the gas pressure detection device, the sulfuric acid concentration detection device, and the second control device; the heating device also works according to the signals generated by the temperature detection device and the second control device.

[0011] Further, the vacuum device operates according to the signals generated by the air pressure detection device, the sulfuric acid concentration detection device, and the second control device, including: when the second control device detects through the liquid level height detection device that the rising speed of the liquid level in the collection device drops to half of the rising speed V1 when the sulfuric acid concentration in the acetylene purification waste sulfuric acid drops to 50%, the second control device outputs a signal to the first control device, and the first control device controls the vacuum device to continue depressurizing at the pressure value maintained in the reaction kettle until the rising speed of the liquid level in the collection device increases to the maximum rising speed V2 of the liquid level when the sulfuric acid concentration drops to 50%; the maximum rising speed V2 of the liquid level is output by the second control device to the first control device; when the rising speed of the liquid level in the collection device increases to the maximum rising speed V2 of the liquid level, the first control device controls the vacuum device and keeps the pressure in the reaction kettle unchanged; at the same time, the first control device controls the working state of the heating device and gradually reduces the temperature in the reaction kettle until the temperature detection device detects that the temperature of the liquid in the reaction kettle drops to the second temperature and remains unchanged.

[0012] Further, during the period when the temperature in the reaction kettle drops from the first temperature to the second temperature; when the rising speed of the liquid level in the collection device fed back by the second control device in the collection device exceeds the rising speed V1 of the recovered sulfuric acid liquid level, the second control device outputs a signal to the first control device, and after receiving the signal, the first control device controls the vacuum device and keeps the pressure at this time; when the rising speed of the liquid level in the collection device fed back by the second control device in the collection device ≤ the rising speed V1 of the recovered sulfuric acid liquid level, the second control device outputs a signal to the first control device, and after receiving the signal, the first control device controls the vacuum device to decompress the reaction kettle until the following first situation or second situation occurs, where the first situation is that the pressure in the reaction kettle drops to the first pressure threshold; the second situation is that the rising speed of the recovered sulfuric acid liquid level in the collection device is less than 1 / 5 of the rising speed V1 of the recovered sulfuric acid liquid level.

[0013] Further, the first temperature is 120°C to 125°C, and the first temperature is preferably 120°C; the first pressure threshold is 0.08 Mpa, the second temperature is 104°C to 106°C, and the second temperature is preferably 105°C.

[0014] Further, a filtering device is further included in the equipment, and the filtering device is arranged between the collection device and the condensation device for filtering and removing impurities from the condensate.

[0015] Further, a heat exchanger is further included in the equipment, and the heat exchanger is arranged between the reaction kettle and the condensation device for heating the waste sulfuric acid in the reaction kettle by using the heat released during condensation.

[0016] The embodiments of the present invention have the following beneficial effects:

[0017] A device control method for purifying waste sulfuric acid is provided. The waste sulfuric acid is industrial acetylene purification waste sulfuric acid with a sulfuric acid concentration of ≥70% in it. In the device, there is a reaction kettle including a gas pressure detection device, a sulfuric acid concentration detection device, and a temperature detection device; a heating device; a stirring device; a distillation device including a diversion device and a vacuum device for decompressing the inside of the reaction kettle; a condensation device; a collection device including a liquid level height detection device and a first control device of the device; the vacuum device works according to the signals generated by the gas pressure detection device and the sulfuric acid concentration detection device; and, the heating device works according to the signals generated by the temperature detection device and the sulfuric acid concentration detection device; when the temperature detection device detects that the temperature of the acetylene purification waste sulfuric acid solution in the reaction kettle is heated by the heating device to a first temperature, the first control device receives the signal from the temperature detection device, the first control device controls the heating device to keep the temperature of the acetylene purification waste sulfuric acid in the reaction kettle at the first temperature, and at the same time the first control device controls the vacuum device to start decompressing the inside of the reaction kettle from normal atmospheric pressure until the sulfuric acid concentration in the acetylene purification waste sulfuric acid in the reaction kettle drops from higher than 50% to 50%; when the sulfuric acid concentration detection device detects that the sulfuric acid concentration in the acetylene purification waste sulfuric acid in the reaction kettle drops to 50%, the first control device receives the signal from the sulfuric acid concentration detection device, the first control device controls the vacuum device to keep the pressure in the reaction kettle at the pressure at this time, and the heating device keeps the temperature in the acetylene purification waste sulfuric acid solution in the reaction kettle at the first temperature.

[0018] This device control method can reduce the electric energy consumed by the continuous decompression of the vacuum device and the electric energy consumed by the operation of the heating device. And by controlling the speed of pressure reduction and reducing the heating time, the service life of each component in the device for purifying industrial acetylene purification waste sulfuric acid can be further extended, especially the service life of the reaction kettle, the heating device, the vacuum device, and the diversion device. And it can prevent the violent boiling of the industrial acetylene purification waste sulfuric acid in the reaction kettle caused by too fast decompression speed, reduce the probability of violent boiling, and reduce the impurity content in the recovered sulfuric acid in the collection device. There is no secondary pollution, no other chemical reagents need to be added during the whole process, no waste residue or waste gas will be generated, and it is environmentally friendly; the investment cost is low, and the device components are all conventional devices, without special materials or processes, which is conducive to popularization and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required to be used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0020] Figure 1 It shows a schematic diagram of the overall structure of a device for purifying waste sulfuric acid provided in this embodiment;

[0021] Figure 2 The internal structural schematic diagram of a device for purifying waste sulfuric acid provided by this embodiment is shown. Detailed implementation manners

[0022] The embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation to the present invention.

[0023] It should be noted that the terms "vertical", "horizontal", "left", "right" and similar expressions used herein are only for the purpose of illustration.

[0024] In the present invention, unless otherwise clearly defined and limited, the terms "installed", "connected", "connected", "fixed" and other terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs. The terms used in the specification of this template are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0027] As Figure 1As shown in the figure, a device for purifying waste sulfuric acid includes a reaction kettle 1, a heating device 2, a stirring device 3, a distillation device 4, a condensation device 5, a collection device 6, a heat exchanger 7, a filtration device 8, and a first control device 91. The first control device 91 can also be any structure placed at any position that realizes the first control device 91 described in this embodiment. The waste sulfuric acid is industrial acetylene purification waste sulfuric acid with a sulfuric acid concentration ≥ 70% contained therein. The industrial acetylene purification waste sulfuric acid contains sulfuric acid with a concentration ≥ 70%, as well as organic substances and impurities such as sulfur and phosphorus. During the existing distillation and recovery process of industrial acetylene purification waste sulfuric acid, a bumping phenomenon is likely to occur under the conditions of relatively high temperature and relatively low pressure, resulting in the presence of organic substances and impurities such as sulfur and phosphorus in the recovered sulfuric acid.

[0028] As Figure 2 shown, a pressure detection device 11 is provided at the top end inside the reaction kettle 1. In this embodiment, the pressure detection device 11 is a pressure sensor. A sulfuric acid concentration detection device 12 for detecting the sulfuric acid concentration in the liquid inside the reaction kettle 1 is provided on the inner wall of the reaction kettle 1. In this embodiment, the sulfuric acid concentration detection device 12 is an online sulfuric acid concentration detector for detecting the percentage concentration of sulfuric acid. A temperature detection device 13 is provided at the bottom of the reaction kettle 1. In this embodiment, the temperature detection device 13 is a temperature sensor. The heating device 2 is arranged outside the reaction kettle 1 for heating the solution inside the reaction kettle 1. The stirring device 3 is arranged inside the reaction kettle 1 for stirring the solution inside the reaction kettle 1. The distillation device 4 includes a vacuum device 41 and a diversion device 42. The vacuum device 41 is used to reduce the pressure inside the reaction kettle 1. In this embodiment, the vacuum device 41 is a vacuum pump, and the diversion device 42 is a packed tower. One end of the diversion device 42 is connected to the reaction kettle 1, and the other end of the diversion device is connected to the collection device 6. The condensation device 5 is used to cool the diversion device 42. The specific internal structure of the condensation device 5 is not shown in the drawings. A liquid level height detection device 61 and a second control device 101 for calculating the rising speed of the liquid level height inside the collection device 6 and feeding back signals are provided inside the collection device 6. The second control device 101 can be any structure placed at any position that realizes the second control device 101 described in this embodiment. With such a setting, the electric energy consumed by the continuous pressure reduction of the vacuum device 41 and the electric energy consumed by the operation of the heating device 2 can be reduced, and the service life of each component inside the entire device for purifying industrial acetylene purification waste sulfuric acid can be extended, especially the service lives of the reaction kettle 1, the heating device 2, the vacuum device 41, and the diversion device 42.

[0029] The reactor 1 is used to hold the acetylene purification waste sulfuric acid to be processed. Its material is stainless steel lined with perfluoroplastic, with a volume of 500 L. It can resist the corrosion of acetylene purification waste sulfuric acid with a sulfuric acid content ≥ 70%, and at the same time resist the pressure drop in the reactor from normal atmospheric pressure to 0.08 MPa. During the pressure reduction process, the reactor 1 is not affected. An external heating device 2 is provided outside the reactor 1. The heating device 2 includes a steam heating coil 21 arranged on the circumferential side of the outer wall of the reactor 1 and a heater 22 arranged at the bottom of the outer wall of the reactor 1. The height of the steam heating coil 21 is about 10 cm lower than the liquid level height of the waste sulfuric acid when the reactor 1 is filled with the acetylene purification waste sulfuric acid to be processed. The heating device 2 is used to heat the temperature of the industrial acetylene purification waste sulfuric acid in the reactor to a first temperature. In this embodiment, the first temperature is 120°C to 125°C, and in this embodiment, it is 120°C. Under standard atmospheric pressure (101.3 kPa), the boiling point of sulfuric acid with a concentration of 5% is 101°C, the boiling point of sulfuric acid with a concentration of 50% is 124°C, and the boiling point of sulfuric acid with a concentration of 98% is 332°C. The decrease in air pressure will cause the boiling point of the liquid to decrease. Under a pressure of 0.08 MPa, the boiling point of sulfuric acid is about 103.5°C. A stirring device 3 for stirring the acetylene purification waste sulfuric acid solution in the reactor 1 and a pressure sensor for detecting the pressure in the reactor are provided at the top inside the reactor 1. The stirring device 3 includes a driving device 31 and stirring blades 32 driven by the driving device 31. The stirring blades 32 are provided with perfluoroplastic to resist the corrosion of acetylene purification waste sulfuric acid with a sulfuric acid content ≥ 70%, and at the same time, can resist the pressure drop in the reactor 1 from normal atmospheric pressure to 0.08 MPa. The driving device 31 can drive the stirring blades 32 to rotate and stir at a speed of 120 rpm. An on-line sulfuric acid concentration detector 12 for detecting the sulfuric acid concentration and a temperature detector 13 for detecting the temperature of the acetylene purification waste sulfuric acid to be processed in the reactor 1 are also provided at the bottom inside the reactor 1.

[0030] The distillation device 4 is connected to the reaction kettle 1. The distillation device 4 includes a vacuum pump and a packed tower. The vacuum pump is used to reduce the pressure inside the reaction kettle 1 from the atmospheric pressure state to the first pressure threshold. In this embodiment, the first pressure threshold is 0.08 MPa. Moreover, the sulfuric acid concentration signal of the on-line sulfuric acid concentration detector 12, the air pressure signal of the air pressure sensor, and the signal of the rising speed of the sulfuric acid solution level recovered in the collection device 6 output by the second control device 101 are transmitted to the first control device 91, and the first control device 91 controls the working state of the vacuum pump. The vacuum pump can work according to the signals generated by the air pressure detection device 11 and the sulfuric acid concentration detection device 12, and the vacuum pump can also work according to the signals generated by the air pressure detection device 11, the sulfuric acid concentration detection device 12, and the second control device 101. The heating device 2 can work according to the signals generated by the temperature detection device 13 and the second control device 101, and the heating device 2 can also work according to the signals generated by the temperature detection device 13 and the on-line sulfuric acid concentration detector 12. The packed tower is connected to the reaction kettle 1. Regular packing is filled inside the packed tower, which is used for distilling the uniformly heated waste sulfuric acid solution.

[0031] In this embodiment, the condensation device 5 is a water-cooled shell-and-tube condenser, which is used to condense the distilled sulfuric acid vapor into a liquid.

[0032] In this embodiment, the collection device 6 is a storage tank, which is used to collect the purified sulfuric acid product after condensation. A control device, a sulfuric acid liquid level height detection device 61 and a second control device 101 are provided in the collection device 6. The second control device 101 can calculate the rising speed of the sulfuric acid liquid level according to the height value fed back by the liquid level height detection device 61 within a fixed time. The second control device 101 transmits the value of the rising speed of the sulfuric acid liquid level to the first control device 91, and the first control device 91 controls the working state of the vacuum pump.

[0033] When the temperature detection device 13 detects that the temperature of the acetylene purification waste sulfuric acid solution in the reactor 1 is heated to the first temperature by the heating device 2, the first control device 91 receives the signal from the temperature detection device 13, and the first control device 91 controls the heating device 2 to maintain the temperature of the acetylene purification waste sulfuric acid in the reactor 1 at the first temperature. At the same time, the first control device 91 controls the vacuum device 41 to start reducing the pressure inside the reactor 1 from normal atmospheric pressure until the sulfuric acid concentration in the acetylene purification waste sulfuric acid in the reactor 1 drops from higher than 50% to 50%. When the sulfuric acid concentration detection device 12 detects that the sulfuric acid concentration in the acetylene purification waste sulfuric acid in the reactor 1 drops to 50%, the first control device 91 receives the signal from the sulfuric acid concentration detection device 12, and the first control device 91 controls the vacuum device 41 to maintain the pressure inside the reactor 1 at the pressure at this time, which is detected by the air pressure detection device 11, and the heating device 2 maintains the temperature of the acetylene purification waste sulfuric acid solution in the reactor 1 at the first temperature. In this embodiment, the first temperature is 120°C to 125°C, preferably 120°C. With this setting, the electric energy consumed by the continuous pressure reduction of the vacuum device 41 can be reduced, and by controlling the speed of pressure reduction, while ensuring the sulfuric acid recovery speed, the service life of each component in the entire equipment for purifying industrial acetylene purification waste sulfuric acid can be extended, especially the service life of the reactor 1, the vacuum device 41, and the diversion device 42. Moreover, it can prevent the violent boiling of the industrial acetylene purification waste sulfuric acid in the reactor 1 caused by too fast pressure reduction speed, and reduce the impurity content in the recovered sulfuric acid in the collection device.

[0034] When the second control device 101 detects through the liquid level height detection device 61 that the rising speed of the liquid level in the collection device 6 drops to half of the rising speed V1 when the sulfuric acid concentration in the acetylene purification waste sulfuric acid drops to 50%, the second control device 101 outputs a signal to the first control device 91. The first control device 91 controls the vacuum pump to continue to reduce the pressure under the pressure in the reaction kettle detected by the pressure detection device 11 until the rising speed of the liquid level in the collection device 6 increases to the maximum rising speed V2 of the liquid level when the sulfuric acid concentration drops to 50%. The maximum rising speed V2 of the liquid level is output from the second control device 101 to the first control device 91. When the rising speed of the liquid level in the collection device 6 increases to the maximum rising speed V2 of the liquid level when the sulfuric acid concentration drops to 50%, the first control device 91 controls the vacuum pump and keeps the pressure in the reaction kettle 1 unchanged. At the same time, the first control device 91 controls the working state of the heating device 2 to gradually reduce the temperature in the reaction kettle 1 to the second temperature detected by the temperature detection device 13 and keep it unchanged. With such a setting, the electric energy consumed by the continuous pressure reduction of the vacuum pump and the electric energy consumed by the working of the heating device 2 can be further reduced. And by controlling the speed of pressure reduction and reducing the heating time, the service life of each component in the entire equipment for purifying industrial acetylene purification waste sulfuric acid can be further extended, especially the service lives of the reaction kettle 1, the heating device 2, the vacuum pump, and the diversion device 42. And it can prevent the violent boiling of the industrial acetylene purification waste sulfuric acid in the reaction kettle 1 caused by too fast pressure reduction speed and reduce the impurity content in the recovered sulfuric acid in the collection device.

[0035] During the period when the temperature in the reaction kettle 1 drops from the first temperature to the second temperature, when the rising speed of the liquid level in the collection device 6 fed back by the second control device 101 in the collection device 6 exceeds the rising speed V1 of the recovered sulfuric acid liquid level, the second control device 101 outputs a signal to the first control device 91. After receiving the signal, the first control device 91 controls the vacuum pump and keeps the pressure at this time. With such a setting, the electric energy consumed by the continuous pressure reduction of the vacuum device 41 and the electric energy consumed by the working of the heating device 2 can be further reduced. And by controlling the speed of pressure reduction and reducing the heating time, the service life of each component in the entire equipment for purifying industrial acetylene purification waste sulfuric acid can be further extended, especially the service lives of the reaction kettle 1, the heating device 2, the vacuum pump, and the diversion device 42.

[0036] During the period when the temperature in the reaction kettle 1 decreases from the first temperature to the second temperature, when the rising speed of the liquid level in the collection device 6 feedback by the second control device 101 in the collection device 6 is lower than or equal to the rising speed V1 of the recovered sulfuric acid liquid level, the second control device 101 outputs a signal to the first control device 91. After receiving the signal, the first control device 91 controls the vacuum pump to decompress the reaction kettle 1 until the following first situation or second situation occurs. Among them, the first situation is that the pressure in the reaction kettle 1 drops to the first pressure threshold. The second situation is that the rising speed of the recovered sulfuric acid liquid level in the collection device 6 is less than 1 / 5 of the rising speed V1 of the recovered sulfuric acid liquid level. With such a setting, the electric energy consumed by the continuous pressure reduction of the vacuum device 41 and the electric energy consumed by the operation of the heating device 2 can be further reduced. And by controlling the speed of pressure reduction and reducing the heating time, the service life of each component in the entire device for purifying industrial acetylene clean waste sulfuric acid can be further extended, especially the service lives of the reaction kettle 1, the heating device 2, the vacuum device 41, and the diversion device 42.

[0037] In this embodiment, the heat exchanger 7 is a shell-and-tube heat exchanger, which is arranged between the reaction kettle 1 and the condensation device 5 and is used to heat the waste sulfuric acid in the reaction kettle 11 by using the heat released during condensation.

[0038] In this embodiment, the filtering device 8 is a bag filter, which is arranged between the collection device 26 and the condensation device 25 and is used to filter and remove impurities from the condensate.

[0039] The control method of the device for purifying industrial acetylene clean waste sulfuric acid is as follows:

[0040] First, add the industrial waste sulfuric acid to be treated into the reaction kettle 1, heat the acetylene clean waste sulfuric acid in the reaction kettle 1 to 120 °C through the heating device 2, and at the same time, the stirring device 3 stirs the acetylene clean waste sulfuric acid solution in the reaction kettle 21 at a speed of 120 rpm to make it fully mixed evenly. The heating and stirring time is 60 minutes. Then open the distillation device 4, and the vacuum pump decompresses the reaction kettle 21. Under this condition, the heated and evenly mixed acetylene clean waste sulfuric acid solution is subjected to a distillation operation. The sulfuric acid vapor distilled out is condensed into a liquid by the condensation device 5, then the condensate is filtered and purified by the filtering device 8, and finally the purified sulfuric acid product is collected by the collection device 26.

[0041] When the temperature of the acetylene purified waste sulfuric acid solution in the reactor 1 is heated to any temperature within the first temperature range of 120°C to 125°C (preferably 120°C in this embodiment), the heating device 2 is controlled by the temperature detector 13 to maintain the temperature of the acetylene purified waste sulfuric acid in the reactor 1 at the first temperature (preferably 120°C in this embodiment). The vacuum pump starts to reduce the pressure inside the reactor 1 from normal atmospheric pressure, and sulfuric acid is distilled out until the sulfuric acid concentration in the acetylene purified waste sulfuric acid in the reactor 1 decreases from above 50% to 50%. When the sulfuric acid concentration in the acetylene purified waste sulfuric acid decreases to 50%, the vacuum pump maintains the pressure inside the reactor 1 at the pressure at this time, and the heating device 2 maintains the temperature of the acetylene purified waste sulfuric acid solution in the reactor 1 at 120°C. When the control device in the collection device 6 detects through the liquid level height detection device 61 that the rising speed of the liquid level drops to half of the rising speed V1 of the liquid level when the sulfuric acid concentration in the acetylene purified waste sulfuric acid decreases to 50%, the second control device 101 receives the signal from the liquid level height detection device 61 and transmits the signal to the first control device 91. The first control device 91 controls the vacuum pump to continue to reduce the pressure until the second control device 101 receives a signal that the rising speed of the liquid level in the collection device 6 increases to the maximum rising speed V2 of the liquid level when the sulfuric acid concentration decreases to 50%.

[0042] When the second control device 101 receives a signal that the rising speed of the liquid level in the collection device 6 increases to the maximum rising speed V2 of the liquid level when the sulfuric acid concentration decreases to 50%, the first control device 91 controls the vacuum pump and then controls the pressure inside the reactor 1 to remain unchanged. At the same time, the first control device 91 further controls the temperature inside the reactor 1 to gradually decrease to the second temperature of 104°C to 106°C (preferably 105°C in this embodiment) detected by the temperature detector 13 and remains unchanged.

[0043] During the period when the temperature inside the reactor 1 decreases from 120°C to 105°C, the first control device 91 controls the working device of the vacuum pump according to the pressure detected by the air pressure detection device 11 inside the reactor 1 and the rising speed of the liquid level height received by the first control device 91 detected by the control device in the collection device 6. When the rising speed of the liquid level in the collection device 6 feedback by the control device in the collection device 6 exceeds the rising speed V1 of the recovered sulfuric acid liquid level, the first control device 91 controls the vacuum pump to maintain the pressure inside the reactor 1 at this time. When the rising speed of the liquid level in the collection device 6 feedback by the second control device 101 in the collection device 6 is lower than or equal to the rising speed V1 of the recovered sulfuric acid liquid level, the control device inside the vacuum pump controls the vacuum pump to reduce the pressure inside the reactor 41 until the following first situation or second situation occurs. Among them, the first situation is that the pressure inside the reactor 1 drops to the first pressure threshold. The second situation is that the rising speed of the recovered sulfuric acid liquid level in the collection device 6 is less than 1 / 5 of the rising speed V1 of the recovered sulfuric acid liquid level. Stop distillation.

[0044] Restore the reactor 1, heating device 2, stirring device 3, vacuum pump, condensation device 5, collection device 6, heat exchanger 7, filtration device 8 and the first control device 91 to the initial state of the equipment for purifying the industrial acetylene scrubbed waste sulfuric acid. Set the temperature to room temperature and the air pressure to the local air pressure. The recovered sulfuric acid in the collection device 6 is the purified sulfuric acid.

[0045] With such settings, the electric energy consumed by the continuous pressure reduction of the vacuum device 41 and the electric energy consumed by the operation of the heating device 2 can be reduced. Moreover, by controlling the speed of pressure reduction and reducing the heating time, the service life of each component in the entire equipment for purifying industrial acetylene scrubbed waste sulfuric acid can be further extended, especially the service life of the reactor 1, heating device 2, vacuum device 41, and diversion device 42. And it can prevent the violent boiling of the industrial acetylene scrubbed waste sulfuric acid in the reactor 1 caused by too fast pressure reduction speed, and reduce the impurity content in the recovered sulfuric acid in the collection device.

[0046] An application of sulfuric acid in purifying industrial acetylene scrubbed waste sulfuric acid by using the above-mentioned equipment for purifying industrial acetylene scrubbed waste sulfuric acid or the control method of using the above-mentioned equipment for purifying industrial acetylene scrubbed waste sulfuric acid. When using the above-mentioned equipment for purifying industrial acetylene scrubbed waste sulfuric acid or the control method of using the above-mentioned equipment for purifying industrial acetylene scrubbed waste sulfuric acid, the electric energy consumed by the continuous pressure reduction of the vacuum device 41 and the electric energy consumed by the operation of the heating device 2 can be reduced. Moreover, by controlling the speed of pressure reduction and reducing the heating time, the service life of each component in the entire equipment for purifying industrial acetylene scrubbed waste sulfuric acid can be further extended, especially the service life of the reactor 1, heating device 2, vacuum device 41, and diversion device 42. And it can prevent the violent boiling of the industrial acetylene scrubbed waste sulfuric acid in the reactor 1 caused by too fast pressure reduction speed, and reduce the impurity content in the recovered sulfuric acid in the collection device.

[0047] In all the examples shown and described here, any specific value should be construed as merely exemplary, not as a limitation. Therefore, other examples of the exemplary embodiments may have different values.

[0048] It should be noted that: Similar reference numerals and letters denote similar items in the following figures. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0049] The above-described embodiments merely represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention.

Claims

1. A control method for equipment used to purify waste sulfuric acid, where the waste sulfuric acid is industrial acetylene purification waste sulfuric acid with a sulfuric acid concentration of ≥ 70% by volume. It is characterized in that the equipment is provided with a reaction kettle including a barometric pressure detection device, a sulfuric acid concentration detection device, and a temperature detection device; a heating device; a stirring device; a distillation device including a diversion device and a vacuum device for reducing the pressure inside the reaction kettle; a condensation device; a collection device including a liquid level height detection device and a first control device of the equipment; The control method of the equipment includes the following steps: S1. Add the industrial acetylene purification waste sulfuric acid to be processed into the reaction kettle, heat the acetylene purification waste sulfuric acid in the reaction kettle to 120 °C through the heating device, and at the same time, the stirring device stirs the acetylene purification waste sulfuric acid solution in the reaction kettle; S2. Open the distillation device, and the vacuum device reduces the pressure of the reaction kettle. Under this condition, perform a distillation operation on the uniformly heated acetylene purification waste sulfuric acid solution; the sulfuric acid vapor distilled by the distillation device is condensed into a liquid by the condensation device and enters the collection device to collect the purified sulfuric acid product; Among them, during the distillation operation, the vacuum device operates according to the signals generated by the barometric pressure detection device and the sulfuric acid concentration detection device; and the heating device operates according to the signals generated by the temperature detection device and the sulfuric acid concentration detection device; When the temperature detection device detects that the temperature of the acetylene purification waste sulfuric acid solution in the reaction kettle is heated by the heating device to a first temperature, the first control device receives the signal from the temperature detection device. The first control device controls the heating device to maintain the temperature of the acetylene purification waste sulfuric acid in the reaction kettle at the first temperature. At the same time, the first control device controls the vacuum device to start reducing the pressure inside the reaction kettle from normal atmospheric pressure until the sulfuric acid concentration in the acetylene purification waste sulfuric acid in the reaction kettle drops from higher than 50% to 50%; when the sulfuric acid concentration detection device detects that the sulfuric acid concentration in the acetylene purification waste sulfuric acid in the reaction kettle drops to 50%, the first control device receives the signal from the sulfuric acid concentration detection device. The first control device controls the vacuum device to maintain the pressure inside the reaction kettle at the current pressure, and the heating device maintains the temperature of the acetylene purification waste sulfuric acid solution in the reaction kettle at the first temperature.

2. The control method according to claim 1, characterized in that The barometric pressure detection device is arranged at the top end inside the reaction kettle; the sulfuric acid concentration detection device is arranged on the inner wall of the reaction kettle for detecting the sulfuric acid concentration in the liquid inside the reaction kettle; the temperature detection device is arranged at the bottom of the reaction kettle; the heating device is arranged outside the reaction kettle for heating the solution inside the reaction kettle; the stirring device is arranged inside the reaction kettle for stirring the solution inside the reaction kettle; one end of the diversion device is connected to the reaction kettle, and the other end of the diversion device is connected to the collection device; the condensation device is used to cool the diversion device; the collection device is also provided with a second control device for calculating the rising speed of the internal liquid level height and feeding back signals; the vacuum device also operates according to the signals generated by the barometric pressure detection device, the sulfuric acid concentration detection device, and the second control device; the heating device also operates according to the signals generated by the temperature detection device and the second control device.

3. The control method according to claim 2, wherein The operation of the vacuum device according to the signals generated by the barometric pressure detection device, the sulfuric acid concentration detection device, and the second control device includes: When the second control device detects through the liquid level detection device that the rising speed of the liquid level in the collection device drops to half of the rising speed V1 when the sulfuric acid concentration in the acetylene purification waste sulfuric acid drops to 50%, the second control device outputs a signal to the first control device. The first control device controls the vacuum device to continue depressurizing at the pressure value maintained in the reaction kettle until the rising speed of the liquid level in the collection device increases to the maximum rising speed V2 of the liquid level when the sulfuric acid concentration drops to 50%. The maximum rising speed V2 of the liquid level is output from the second control device to the first control device. When the rising speed of the liquid level in the collection device increases to the maximum rising speed V2 of the liquid level, the first control device controls the vacuum device and keeps the pressure in the reaction kettle unchanged. At the same time, the first control device controls the working state of the heating device to gradually reduce the temperature in the reaction kettle until the temperature detection device detects that the temperature of the liquid in the reaction kettle drops to the second temperature and remains unchanged.

4. The control method according to claim 3, characterized in that, During the period when the temperature in the reaction kettle drops from the first temperature to the second temperature; When the rising speed of the liquid level in the collection device feedback by the second control device in the collection device exceeds the rising speed V1 of the recovered sulfuric acid liquid level, the second control device outputs a signal to the first control device. After receiving the signal, the first control device controls the vacuum device and maintains the pressure at this time. When the rising speed of the liquid level in the collection device feedback by the second control device in the collection device ≤ the rising speed V1 of the recovered sulfuric acid liquid level, the second control device outputs a signal to the first control device. After receiving the signal, the first control device controls the vacuum device to decompress the reaction kettle until the following first situation or second situation occurs, where The first situation is that the pressure in the reaction kettle drops to the first pressure threshold; The second situation is that the rising speed of the recovered sulfuric acid liquid level in the collection device is less than 1 / 5 of the rising speed V1 of the recovered sulfuric acid liquid level.

5. The control method according to claim 4, wherein The first temperature is 120 °C, the first pressure threshold is 0.08 Mpa, and the second temperature is 104 °C - 106 °C.

6. The control method according to claim 1, wherein The equipment also includes a filtration device, which is arranged between the collection device and the condensation device and is used to filter and remove impurities from the condensate.

7. The control method according to claim 1, wherein The equipment also includes a heat exchanger, which is arranged between the reaction kettle and the condensation device and is used to heat the waste sulfuric acid in the reaction kettle by using the heat released during condensation.

Images