Self-consistent resourceful treatment apparatus and method for salt-containing wastewater and hydrochloric acid-containing waste gas

Abstract

A self-consistent resourceful treatment apparatus and method for salt-containing wastewater and hydrochloric acid-containing waste gas, relating to the technical field of industrial wastewater and waste gas treatment. The method comprises: simultaneously introducing the salt-containing wastewater and the hydrochloric acid-containing waste gas into a self-consistent absorption reactor to perform self-consistent absorption reaction; gradually precipitating NaCl crystals from salt in the salt-containing wastewater according to a common-ion effect to obtain a solid-liquid mixture; and performing settling separation on the solid-liquid mixture to obtain industrial-grade salt and industrial-grade hydrochloric acid. According to the treatment method, industrial wastewater and industrial waste gas can be synchronously reacted to obtain industrial-grade salt, the obtained industrial-grade salt can be directly commercially available or used in the chlor-alkali industry, and the obtained hydrochloric acid can be used as a raw material for producing a refrigerant CaCl2, such that resource utilization is realized at the same time. The treatment method is different from a conventional spray-type reactor method, does not use a tower plate and a filler, and does not cause the problem that a reactor is blocked by discharged salt.

Description

A self-consistent resource treatment device and method for salt-containing wastewater and hydrochloric acid waste gas Technical Field

[0001] The present invention relates to the technical field of industrial wastewater and waste gas treatment, and in particular to a self-consistent resource treatment method for saline wastewater and hydrochloric acid waste gas. Background Art

[0002] Industrial development is a major source of environmental pollution, and the treatment of saline wastewater is a key focus in addressing this issue. Currently, most saline wastewater treatment technologies rely on biochemical treatment. However, due to the variability and presence of recalcitrant organic pollutants, conventional biochemical treatment processes often struggle to be effective, resulting in treated effluent failing to meet discharge standards. Research has also explored the use of natural evaporation and crystallization, as well as mechanical evaporation. Natural evaporation and crystallization require large evaporation ponds for natural evaporation, which, due to their large footprint and low efficiency, cannot meet the requirements for saline wastewater treatment. Compared to natural evaporation and crystallization, mechanical evaporation offers advantages: first, the required equipment footprint is smaller; second, mechanical evaporation is more efficient. However, mechanical evaporation is prone to scaling on the inner walls of the evaporator system, resulting in blockage of the channels by the discharged salt and long-term corrosion of the pipes. Therefore, there is a need for a more efficient, less clogging, and energy-efficient method for treating saline wastewater.

[0003] Industrial production often generates waste gas containing hydrochloric acid. The large amount of hydrogen chloride in this waste gas is highly corrosive. Directly discharging it into the environment would cause significant environmental pollution. Existing waste gas absorption systems are currently used to absorb the highly corrosive gases before discharge. However, existing waste gas absorption technologies often utilize conventional absorption towers, which are ineffective at absorbing hydrogen chloride, resulting in a significant amount of residual hydrogen chloride in the discharged waste gas.

[0004] Therefore, how to obtain a method that can synergistically treat salt-containing wastewater and hydrochloric acid waste gas and realize their resource utilization is a technical problem that needs to be solved at present.

[0005] Summary of the Invention

[0006] The purpose of the present invention is to provide a self-consistent resource recovery method for the treatment of saline wastewater and hydrochloric acid waste gas, so as to solve the technical problems in the prior art of easy scaling, low absorption efficiency, high treatment cost and great environmental risks caused by the separate treatment of saline wastewater and hydrochloric acid waste gas.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0008] [Article 26 of the detailed rules, 05.03.2025] A self-consistent resource recovery device for treating salt-containing wastewater and hydrochloric acid-containing waste gas, wherein the self-consistent absorption reactor comprises an absorption tower, a circulating cooler and a cooling forced circulation pump, wherein a wastewater inlet is provided at the bottom end of the absorption tower, the bottom end of the absorption tower is connected to the bottom end of the circulating cooler through a pipeline, the pipeline at the top end of the circulating cooler extends to the interior of the absorption tower, and a cooling forced circulation pump is provided on the pipeline connecting the bottom end of the circulating cooler and the absorption tower.

[0009] Furthermore, a venturi tube is provided at the top of the absorption tower, and a water inlet is provided at the bottom. A horizontal air inlet is provided at the top of the venturi tube, and a tubular trumpet-type nozzle is provided at the bottom of the venturi tube. The longitudinal liquid inlet of the venturi tube is connected to one end of the absorption liquid circulation pump through a pipeline, and the other end of the absorption liquid circulation pump is connected to the inside of the absorption tower, and the air inlet inhales hydrochloric acid waste gas.

[0010] Furthermore, a demister is provided at the top of the absorption tower.

[0011] Furthermore, a baffle is provided at the outlet of the pipe extending from the top of the circulating cooler to the inner part of the absorption tower.

[0012] Furthermore, a retaining ring is provided on the inner wall of the absorption tower at the position where the absorption tower is connected to the absorption liquid circulation pump.

[0013] Furthermore, a liquid level meter is installed on one side of the absorption tower.

[0014] Furthermore, a pipeline is provided at the bottom end of the absorption tower to connect with the automatic solid-liquid level regulating valve, a discharge valve is provided at the bottom end of the automatic solid-liquid level regulating valve, and the automatic solid-liquid level regulating valve is interlocked with the discharge valve.

[0015] In view of the above-mentioned device, the present invention also provides a self-consistent resource treatment method for saline wastewater and hydrochloric acid waste gas, comprising the following steps:

[0016] [Article 26 of the Detailed Rules, 05.03.2025] (1) The salt-containing wastewater and the hydrochloric acid-containing waste gas are simultaneously introduced into a self-consistent absorption reactor to carry out a self-consistent absorption reaction to obtain an absorption liquid;

[0017] [Article 26 of the Regulations, 05.03.2025] (2) The absorption liquid is cooled by a circulating cooler and a cooling forced circulation pump to control the temperature of the absorption liquid to facilitate the absorption of HCl in the exhaust gas;

[0018] [Article 26 of the Detailed Rules, 05.03.2025](3) The absorption liquid obtained is continuously subjected to a self-consistent absorption reaction with the hydrochloric acid-containing waste gas through an absorption liquid circulation pump, solid is precipitated, and a solid-liquid mixture is obtained. After sedimentation and centrifugal separation, the solid-liquid mixture is obtained to obtain industrial-grade salt and industrial-grade hydrochloric acid.

[0019] Furthermore, the flow rate of the saline wastewater is 4.0-5.0m 3 / h, preferably 4.2 to 4.8 m 3 / h, more preferably 4.5m 3 / h; the flow rate of the hydrochloric acid waste gas is 200.0~350.0m 3 / h, preferably 230.0~320.0m 3 / h, more preferably 280.0 to 300.0 m 3 / h.

[0020] [Article 26 of the Detailed Rules, 05.03.2025] Furthermore, in the steps (1) and (3), the temperature of the self-consistent absorption reaction is independently 25 to 35°C, preferably 28 to 32°C, and more preferably 29 to 31°C; the residence time of the material in the self-consistent absorption reactor is independently 60 to 90 min, preferably 75 to 85 min, and more preferably 80 min.

[0021] [Article 26 of the Detailed Rules, 05.03.2025] Furthermore, in the step (2), the circulating cooler cools the absorption liquid to 25-35°C, preferably 22-28°C, and more preferably 24-26°C.

[0022] [Article 26 of the Detailed Rules, 05.03.2025] In the technical solution of the present invention, the self-consistent resource recovery method for treating saline wastewater and hydrochloric acid waste gas can be successfully implemented in the self-consistent resource recovery device for treating saline wastewater and hydrochloric acid waste gas.

[0023] [Article 26 of the Detailed Rules, 05.03.2025] Another technical solution of the present invention provides an industrial-grade salt and industrial-grade hydrochloric acid prepared by resource recovery, which are prepared by the self-consistent resource recovery treatment method of salt-containing wastewater and hydrochloric acid-containing waste gas.

[0024] [Article 26 of the Detailed Rules, 05.03.2025] The TOC of the industrial-grade salt prepared is less than 5 mg / L, and the purity of the industrial-grade salt is greater than 99.0%, more preferably greater than or equal to 99.3%, more preferably greater than or equal to 99.5%, and more preferably greater than or equal to 99.8%.

[0025] The industrial-grade hydrochloric acid prepared meets the requirements of qualified products, more preferably meets the requirements of first-class products, and further preferably meets the requirements of superior products.

[0026] In some feasible cases of the present invention, the technical solution of the present invention can dissolve industrial salt produced as a by-product in the production of pharmaceutical raw materials and intermediates, such as industrial salt with a TOC of more than 5000 mg / L, into a saturated solution with deionized water and then conduct a self-consistent resource treatment method with hydrochloric acid-containing waste gas. The method of the present invention can obtain high-quality refined industrial salt with a TOC of less than 5 mg / L, and the quality meets the requirements of GB / T5462-2015 chlor-alkali industry.

[0027] Beneficial effects of the present invention:

[0028] The treatment method of the present invention can synchronously react industrial wastewater and industrial waste gas to obtain industrial-grade salt and industrial hydrochloric acid; the present invention simultaneously introduces saline wastewater and hydrochloric acid waste gas into a self-consistent absorption and precipitation reactor to carry out a self-consistent absorption reaction. According to the common ion effect, the salt in the saline wastewater gradually precipitates NaCl crystals to obtain a solid-liquid mixture. After sedimentation separation, the solid-liquid mixture is subjected to sedimentation separation to obtain industrial-grade salt and industrial-grade hydrochloric acid, thereby avoiding the large space occupied by the required equipment, the blockage of the salt outlet channel by excessive scaling on the inner wall, and the easy corrosion of the pipeline over a long period of time. This solves the problem in the prior art that saline wastewater and hydrochloric acid waste gas are easily scaled and the treatment efficiency is low when they are treated separately. The treatment method of the present invention can synchronously react industrial wastewater and industrial waste gas to obtain industrial-grade salt. The obtained industrial-grade salt can be directly sold on the market or used in the chlor-alkali industry, and the obtained hydrochloric acid can be used as a raw material for producing the refrigerant CaCl2; thereby simultaneously achieving resource utilization.

[0029] The obtained industrial-grade salt can be directly sold commercially or used in the chlor-alkali industry, and the obtained industrial hydrochloric acid can be used as a raw material for the refrigerant CaCl2. The treatment method of the present invention is different from the conventional spray absorption reactor method. It does not use trays and packings, and the problem of salt clogging the reactor will not occur.

[0030] The self-consistent absorption reactor of the present invention is provided with a cooling forced circulation pump and a circulating cooler, which can greatly reduce the temperature inside the absorption tower and perform heat exchange. A venturi is provided at the top of the absorption tower, which continuously sucks the hydrochloric acid-containing waste gas under the action of the absorption circulating liquid flow to ensure the normal reaction inside the absorption tower, thereby producing salt and industrial hydrochloric acid. The HCl in the hydrochloric acid-containing waste gas is completely absorbed by the wastewater to generate hydrochloric acid. According to the common ion effect, the salt in the wastewater is completely precipitated to generate salt particles; thus, the NaCl in the wastewater is completely precipitated to generate industrial salt, and the HCl in the waste gas is absorbed to generate industrial hydrochloric acid, thereby realizing its resource utilization. While treating wastewater and waste gas, waste utilization is achieved, which is more cost-effective, so as to realize the resource utilization of salt-containing wastewater and hydrochloric acid-containing waste gas. The self-consistent absorption reactor of the present invention does not require the setting of tower plates, does not require filling materials, and has direct gas-liquid contact reaction. The common ion effect occurs in the reactor, and salt can be precipitated. The following reactions occur in the reactor:

[0031] NaCl (liquid) + HCl (gas) → NaCl (solid, commercially available) + HCl (liquid, can be used as a raw material for preparing the refrigerant CaCl2).

[0032] In the technical solution of the present invention, the self-consistent absorption reactor, with its specific and compact structure, involves processes such as venturi absorption, laminar enrichment, orderly crystal growth, forced circulation cooling, and efficient liquid-solid separation. The efficient and stable control of its material balance and thermodynamic equilibrium requires model simulation calculations and unique innovative thinking. It can not only realize the resource treatment of salt-containing wastewater and hydrochloric acid-containing waste gas, but also realize the refining of crude salt. The obtained crystalline salt has high purity and can be used efficiently in industrial areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] [Article 26 of the Detailed Rules, 05.03.2025] Figure 1 is a schematic structural diagram of the self-consistent absorption reactor of the present invention, wherein: 1-absorption tower, 2-circulating cooler, 3-liquid level gauge, 4-solid-liquid level automatic regulating valve, 5-demister, 6-Venturi tube, 7-baffle, 8-absorption liquid circulation pump, 9-cooling forced circulation pump, 10-discharge valve, 11-baffle ring, 12-wastewater inlet, 13-lateral air inlet, 14-exhaust gas outlet.

[0034] FIG2 is a crystal microscope photograph of NaCl obtained in Example 1. DETAILED DESCRIPTION

[0035] [Article 26, 05.03.2025] The present invention provides a self-consistent resource recovery method for treating saline wastewater and hydrochloric acid waste gas, comprising the following steps:

[0036] [Article 26 of the Detailed Rules, 05.03.2025] 1) The salt-containing wastewater and the hydrochloric acid-containing waste gas are simultaneously introduced into a self-consistent absorption reactor to carry out a self-consistent absorption reaction to obtain an absorption liquid;

[0037] [Article 26, 05.03.2025] 2) Cooling the absorption liquid by a circulating cooler and a cooling forced circulation pump to control the absorption liquid temperature to facilitate the absorption of HCl in the exhaust gas;

[0038] [Article 26 of the Detailed Rules, 05.03.2025] 3) The obtained absorption liquid continues to undergo a self-consistent absorption reaction with the hydrochloric acid-containing waste gas through an absorption liquid circulation pump, precipitating solids to obtain a solid-liquid mixture, and after sedimentation and centrifugal separation of the solid-liquid mixture, industrial-grade salt and industrial-grade hydrochloric acid are obtained.

[0039] [Article 26 of the Detailed Rules, 05.03.2025] In the present invention, the saline wastewater contains NaCl, and the hydrochloric acid waste gas contains HCl gas.

[0040] In the present invention, the flow rate of the saline wastewater is 4.0-5.0m3 / h, preferably 4.2 to 4.8 m 3 / h, more preferably 4.5m 3 / h; the flow rate of the hydrochloric acid waste gas is 200.0~350.0m 3 / h, preferably 230.0~320.0m 3 / h, more preferably 280.0 to 300.0 m 3 / h.

[0041] In the present invention, in step 1) and step 3), the temperature of the self-consistent absorption reaction is independently 25-35°C, preferably 28-32°C, and more preferably 29-31°C; the residence time of the material in the self-consistent absorption reactor is independently 60-90 min, preferably 75-85 min, and more preferably 80 min.

[0042] In the present invention, in step 2), the circulating cooler cools the absorption liquid to 25-35°C, preferably 22-28°C, and more preferably 24-26°C.

[0043] In the present invention, the self-consistent resource recovery method for treating saline wastewater and hydrochloric acid waste gas can also be used for refining crude salt.

[0044] In the present invention, the self-consistent absorption reactor includes an absorption tower 1, a circulating cooler 2, and a cooling forced circulation pump 9. The bottom end of the absorption tower 1 is provided with a wastewater inlet 12. The bottom end of the absorption tower 1 is connected to the bottom end of the circulating cooler 2 through a pipe. The pipe at the top of the circulating cooler 2 extends to the interior of the absorption tower 1. The pipe connecting the bottom end of the circulating cooler 2 to the absorption tower 1 is provided with a cooling forced circulation pump 9. The top end of the circulating cooler 2 is provided with a shell-side water inlet, and the bottom end is provided with a shell-side water outlet. Water enters from the top and exits from the bottom, exchanges heat with the tube-side absorption liquid inside the circulating cooler 2, and cools it down. The absorption liquid is enhanced cooled by the circulating cooler 2 and the cooling forced circulation pump 9, which can quickly reduce the temperature generated by the reaction. The circulating cooler 2 is provided with a cooling water inlet and outlet that enter from the top and exit from the bottom.

[0045] In the present invention, the absorption tower 1 is provided with a venturi 6 at the top and a water inlet at the bottom. The venturi 6 is used to absorb hydrochloric acid tail gas. A tubular trumpet nozzle is provided at the bottom of the venturi 6. The top of the venturi 6 is provided with a transverse air inlet 13. The longitudinal liquid inlet of the venturi 6 is connected to one end of an absorption liquid circulation pump 8 via a pipeline. The other end of the absorption liquid circulation pump 8 is connected to the interior of the absorption tower 1. The air inlet absorbs hydrochloric acid waste gas. The top of the absorption tower 1 is also provided with an exhaust gas outlet 14, and the exhaust gas at this exhaust gas outlet is sent to the exhaust gas absorption device.

[0046] In the present invention, a demister 5 is further provided at the top of the absorption tower 1 for removing liquid foam in the residual tail gas.

[0047] In the present invention, a baffle 7 is provided at the outlet of the pipe extending from the top of the circulating cooler 2 to the inner pipe of the absorption tower 1. The baffle 7 changes the absorption liquid in the pipe from turbulent flow to laminar flow, so as to facilitate the sedimentation of salt particles.

[0048] In the present invention, a retaining ring 11 is further provided on the inner wall of the absorption tower 1 at the position where it is connected to the absorption liquid circulation pump 8, which is used to separate the absorption reaction zone and the precipitation and sedimentation zone to ensure that the circulating absorption liquid drawn in by the absorption liquid circulation pump 8 carries as few salt particles as possible, so as to facilitate the normal operation of the absorption liquid circulation pump, and also facilitate the absorption of HCl in the exhaust gas and the precipitation and sedimentation of salt particles.

[0049] The self-consistent absorption reactor of the present application is provided with a baffle 7 and a baffle ring 11. The area enclosed by the baffle ring in the lower layer of the baffle and the lower cone and slender "salt leg" of the absorption reactor form a laminar flow area, which is conducive to the sedimentation and enrichment of solids, ensuring that the circulating absorption liquid does not contain or contains as few solid particles as possible, preventing clogging of the pipeline and improving the liquid-solid separation effect.

[0050] In the present invention, a liquid level meter 3 is installed on one side of the absorption tower 1 , and the liquid level inside the absorption tower 1 is determined by the liquid level meter 3 .

[0051] In the present invention, the bottom end of the absorption tower 1 is also provided with a pipeline connected to the solid-liquid level automatic regulating valve 4, and the bottom end of the solid-liquid level automatic regulating valve 4 is provided with a discharge valve 10. The solid-liquid level automatic regulating valve 4 is interlocked with the discharge valve 10. The solid-liquid level automatic regulating valve 4 is used to control the solid-liquid level of the absorption tower, and the discharge valve 10 is used to control the discharge to discharge salt and industrial hydrochloric acid from the centrifuge.

[0052] In the present invention, saline wastewater enters the bottom end of the absorption tower 1, and waste gas containing hydrochloric acid is sucked into the transverse air inlet provided at the top end of the venturi 6. After being forcibly mixed with the absorption liquid discharged from the absorption liquid circulation pump 8 through the venturi 6, it enters the absorption tower 1. The wastewater absorbs HCl in the waste gas to generate hydrochloric acid. The salt in the wastewater is gradually or even completely precipitated due to the common ion effect. The salt particles and industrial hydrochloric acid settle to the bottom end of the absorption tower 1 and are discharged through the discharge valve 10. The salt and industrial hydrochloric acid are separated by a centrifuge. After the salt meets the quality standards after analysis, it can be sold as industrial salt, and the industrial hydrochloric acid can be used as a raw material for preparing the refrigerant CaCl2. The exhaust gas after absorbing HCl passes through the demister 5 and enters other exhaust gas treatment devices to meet emission standards. The absorption liquid inside the absorption tower 1 will be affected by the cooling forced circulation pump 9, and enter the circulation cooler 2 from the pipe connected to the circulation cooler 2 at the bottom of the absorption tower 1. The cooled absorption liquid enters the absorption tower 1 from the top pipe of the circulation cooler 2, forming turbulence. The turbulent flow is blocked by the baffle 7 inside the absorption tower 1, forming laminar flow, thereby alleviating the tumbling of the fluid and facilitating the sedimentation of the generated salt particles.

[0053] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0054] Example 1

[0055] The saline wastewater and hydrochloric acid waste gas are continuously introduced into the self-consistent absorption reactor at the same time. The flow rate of the saline wastewater is 4.3m 3 / h, the inlet flow rate of hydrochloric acid waste gas is 260.0m 3 / h.

[0056] The saline wastewater and hydrochloric acid waste gas undergo a self-consistent absorption reaction in the reactor. The absorption reaction lasts for 65 minutes. The absorption liquid in the absorption tower is cooled by a circulating cooler to reduce the reaction temperature. After the absorption liquid is cooled to 25°C, it is further self-consistently absorbed by the hydrochloric acid waste gas sucked into the venturi through the absorption liquid circulation pump. During the continuous absorption reaction, the salt in the saline wastewater gradually precipitates NaCl crystals due to the common ion effect. Analysis shows that the NaCl crystals have completely precipitated when the hydrochloric acid concentration reaches 31%. The resulting solid-liquid mixture is separated in a centrifuge to produce solid industrial-grade salt and liquid industrial-grade hydrochloric acid. The resulting industrial salt is tested according to the national standard GB / T5462-2015 and all indicators meet the requirements. In this embodiment, a self-consistent absorption reactor with the aforementioned structure forms a laminar flow region within the gas-liquid mixing zone, allowing orderly growth of NaCl crystals. This orderly growth process results in transparent NaCl crystals, free of any impurities that could affect NaCl quality. This allows for refined NaCl, suitable for use in the chlor-alkali industry. As shown in Figure 2, a microscopic photograph of NaCl crystals grown in the laminar flow region demonstrates uniform, transparent particle size and absence of impurities. The resulting liquid industrial-grade hydrochloric acid meets the quality standards specified in GB / T 320-2006.

[0057] Example 2

[0058] The saline wastewater and hydrochloric acid waste gas are continuously introduced into the self-consistent absorption reactor at the same time. The flow rate of the saline wastewater is 4.5m 3 / h, the inlet flow rate of hydrochloric acid waste gas is 290.0m 3 / h.

[0059] The salt-containing wastewater and hydrochloric acid waste gas undergo a self-consistent absorption reaction in a reactor. The absorption reaction lasts for 75 minutes. The absorption liquid in the absorption tower is cooled by a circulating cooler to reduce the temperature generated by the reaction. After the absorption liquid is cooled to 28°C, it is further self-consistently absorbed by the hydrochloric acid waste gas sucked into the venturi through the absorption liquid circulation pump. During the continuous absorption reaction, the salt in the salt-containing wastewater gradually precipitates NaCl crystals due to the common ion effect. Analysis shows that when the hydrochloric acid concentration reaches 30.5%, the NaCl crystals are completely precipitated. The resulting solid-liquid mixture is separated in a centrifuge to obtain solid industrial-grade salt and liquid industrial-grade hydrochloric acid. The obtained industrial salt is tested according to the national standard GB / T5462-2015, and all indicators meet the requirements. The microscopic photograph of the obtained NaCl crystals is basically the same as that in Example 1, with uniform particle size, transparency, and no encapsulation. The liquid industrial-grade hydrochloric acid meets the excellent product indicators in GB / T 320-2006.

[0060] Example 3

[0061] The saline wastewater and hydrochloric acid waste gas are continuously introduced into the self-consistent absorption reactor at the same time. The flow rate of the saline wastewater is 5.0m 3 / h, the inlet flow rate of hydrochloric acid waste gas is 350m 3 / h.

[0062] The salt-containing wastewater and hydrochloric acid waste gas undergo a self-consistent absorption reaction in a reactor. After the absorption reaction is allowed to proceed for 75 minutes, the absorption liquid in the absorption tower is cooled by a circulating cooler to reduce the temperature generated by the reaction. After the absorption liquid is cooled to 33°C, it is further subjected to a self-consistent absorption reaction with the hydrochloric acid waste gas sucked into the venturi by the absorption liquid circulation pump. During the continuous absorption reaction, the salt in the salt-containing wastewater gradually precipitates NaCl crystals due to the common ion effect. Analysis shows that when the hydrochloric acid concentration reaches 31.5%, the NaCl crystals are completely precipitated. The resulting solid-liquid mixture is centrifuged and separated to obtain solid industrial-grade salt and liquid industrial-grade hydrochloric acid. The obtained industrial salt is tested according to the national standard GB / T5462-2015, and all indicators meet the requirements. The microscopic photograph of the obtained NaCl crystals is basically the same as that in Example 1, with uniform and transparent particle size and no encapsulation. The liquid industrial-grade hydrochloric acid meets the high-quality product indicators in GB / T 320-2006.

[0063] The industrial-grade salt obtained in Examples 1 to 3 was tested for purity according to the national standard GB / T5462-2015. The results are shown in Table 1 below:

[0064] Table 1 Purity of the industrial grade salt obtained in Examples 1 to 3

[0065] As can be seen from the above embodiments, the present invention provides a self-consistent resource recovery method for treating saline wastewater and hydrochloric acid waste gas. The treatment method of the present invention not only conducts a self-consistent reaction on two industrial pollutants and removes them at the same time, but also generates high-purity salt that can be used industrially. The self-consistent absorption reactor of the present invention does not cause problems such as salt blockage and corrosion of pipelines, and can continuously treat saline wastewater and hydrochloric acid waste gas with high efficiency. The industrial hydrochloric acid obtained after the reaction can be used as a raw material for preparing the refrigerant CaCl2. The treatment method of the present invention is simple and easy to implement, the equipment occupies a small area, and is easy to operate. It can be used to treat saline wastewater and hydrochloric acid waste gas on an industrial scale.

[0066] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, several improvements and modifications can be made, including using the present invention to refine the relevant crude salt. These improvements and modifications should also be considered as the scope of protection of the present invention.

Claims

1. A self-consistent resource treatment device for saline wastewater and hydrochloric acid waste gas, characterized in that: The self-consistent absorption reactor comprises an absorption tower (1), a circulating cooler (2) and a cooling forced circulation pump (9), wherein the bottom end of the absorption tower (1) is connected to the bottom end of the circulating cooler (2) via a pipeline, the pipeline at the top end of the circulating cooler (2) extends to the interior of the absorption tower (1), and a cooling forced circulation pump (9) is arranged on the pipeline connecting the bottom end of the circulating cooler (2) and the absorption tower (1).

2. The self-consistent resource treatment device for saline wastewater and hydrochloric acid waste gas according to claim 1 is characterized in that: The top of the absorption tower (1) is provided with a venturi tube (6), the bottom of the absorption tower (1) is provided with a wastewater inlet (12), the top of the venturi tube (6) is provided with a transverse air inlet (13), the bottom of the venturi tube (6) is provided with a tubular trumpet-shaped nozzle, the longitudinal liquid inlet of the venturi tube is connected to one end of an absorption liquid circulation pump (8) through a pipeline, the other end of the absorption liquid circulation pump (8) is connected to the inside of the absorption tower (1), and the air inlet sucks in waste gas containing hydrochloric acid.

3. The self-consistent resource treatment device for saline wastewater and hydrochloric acid waste gas according to claim 1 is characterized in that: A demister (5) is also provided at the top of the absorption tower (1).

4. The self-consistent resource treatment device for saline wastewater and hydrochloric acid waste gas according to claim 1 is characterized in that: A baffle (7) is provided at the outlet of the pipeline extending from the top of the circulating cooler (2) to the inside of the absorption tower (1).

5. The self-consistent resource treatment device for saline wastewater and hydrochloric acid waste gas according to claim 1 is characterized in that: A retaining ring (11) is also provided on the inner wall of the absorption tower (1) at the position where it is connected to the absorption liquid circulation pump (8).

6. The self-consistent resource treatment device for saline wastewater and hydrochloric acid waste gas according to claim 1 is characterized in that: A liquid level meter (3) is installed on one side of the absorption tower (1).

7. The self-consistent resource treatment device for saline wastewater and hydrochloric acid waste gas according to claim 1 is characterized in that: The bottom end of the absorption tower (1) is also provided with a pipeline connected to the automatic solid-liquid level regulating valve (4), and the bottom end of the automatic solid-liquid level regulating valve (4) is provided with a discharge valve (10), and the automatic solid-liquid level regulating valve (4) is interlocked with the discharge valve (10).

8. A self-consistent resource treatment method for saline wastewater and hydrochloric acid waste gas, characterized in that: The following steps are involved: (1) introducing salt-containing wastewater and hydrochloric acid-containing waste gas into a self-consistent absorption reactor at the same time to carry out a self-consistent absorption reaction to obtain an absorption liquid; (2) Cooling the absorption liquid by a circulating cooler and a cooling forced circulation pump to control the temperature of the absorption liquid to facilitate the absorption of HCl in the exhaust gas; (3) The obtained absorption liquid continues to undergo a self-consistent absorption reaction with the hydrochloric acid-containing waste gas through an absorption liquid circulation pump, solids are precipitated, and a solid-liquid mixture is obtained. After sedimentation and centrifugal separation, the solid-liquid mixture is obtained to obtain industrial-grade salt and industrial-grade hydrochloric acid.

9. The self-consistent resource treatment method for saline wastewater and hydrochloric acid waste gas according to claim 8, characterized in that: The flow rate of the salt-containing wastewater is 4.0-5.0 m3 / h, preferably 4.2-4.8 m3 / h, and more preferably 4.5 m3 / h; the flow rate of the hydrochloric acid-containing waste gas is 200.0-350.0 m3 / h, preferably 230.0-320.0 m3 / h, and more preferably 280.0-300.0 m3 / h.

10. The self-consistent resource treatment method for saline wastewater and hydrochloric acid waste gas according to claim 9, characterized in that: In the steps (1) and (3), the temperature of the self-consistent absorption reaction is independently 25 to 35°C, preferably 28 to 32°C, and more preferably 29 to 31°C; the residence time of the material in the self-consistent absorption reactor is independently 60 to 90 min, preferably 75 to 85 min, and more preferably 80 min.

11. The self-consistent resource treatment method for saline wastewater and hydrochloric acid waste gas according to claim 10, characterized in that: In the step (2), the circulating cooler cools the absorption liquid to 25-35°C, preferably 22-28°C, and more preferably 24-26°C.

12. The self-consistent resource treatment method for saline wastewater and hydrochloric acid waste gas according to any one of claims 8 to 11, characterized in that: The self-consistent absorption reactor is a self-consistent resource treatment device for salt-containing wastewater and hydrochloric acid waste gas as described in any one of claims 1-7.

13. An industrial-grade salt and industrial-grade hydrochloric acid prepared by resource utilization, characterized in that: The method is prepared by the self-consistent resource recovery treatment method of salt-containing wastewater and hydrochloric acid waste gas according to any one of claims 8 to 12.

14. The industrial-grade salt and industrial-grade hydrochloric acid prepared by resource utilization according to claim 13, characterized in that: The TOC of the prepared industrial-grade salt is less than 5 mg / L, and the purity of the industrial-grade salt is greater than 99.0%, more preferably greater than or equal to 99.3%, more preferably greater than or equal to 99.5%, and more preferably greater than or equal to 99.8%.

15. The industrial-grade salt and industrial-grade hydrochloric acid prepared by resource utilization according to claim 13, characterized in that: The industrial-grade hydrochloric acid prepared meets the requirements of qualified products, more preferably meets the requirements of first-class products, and further preferably meets the requirements of superior products.

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