Energy-saving and consumption-reducing sodium hypochlorite production device and production method

Abstract

The invention provides an energy-saving and consumption-reducing sodium hypochlorite production device and a production method. The device comprises an electrolytic chlorine production unit and an alkali liquor preparation unit, the electrolytic chlorine production unit is connected with a chlorine gas washing tower, the chlorine gas washing tower is connected with a falling film absorber and a chlorine gas cooler, the chlorine gas cooler, a water mist catcher and a chlorine gas drying and liquefying unit are sequentially connected, and the chlorine gas drying and liquefying unit is connected with a sodium hypochlorite reaction unit; the alkali liquor preparation unit is connected with the alkali liquor head tank through the alkali liquor delivery pump, the alkali liquor head tank is connected with the falling film absorber, a liquid outlet of the falling film absorber is connected with the sodium hypochlorite reaction unit, and a liquid outlet of the sodium hypochlorite reaction unit is connected with the sodium hypochlorite storage tank through the sodium hypochlorite delivery pump. According to the device provided by the invention, alkali liquor and wet chlorine are firstly subjected to primary reaction in the falling film absorber and then are subjected to secondary reaction with dry chlorine in the sodium hypochlorite reaction unit, so that high-quality sodium hypochlorite is generated, and the device is high in automation degree, stable in production operation, simple to operate and relatively high in operation flexibility.

Description

Technical Field

[0001] The invention relates to the technical field of sodium hypochlorite production, in particular to a sodium hypochlorite energy-saving and consumption-reducing production device and a production method. Background Art

[0002] Sodium hypochlorite is a widely used chlorine-containing oxygen compound. It is a strong oxidant, bleaching agent, disinfectant and deodorant. It has become a commonly used chemical product due to its low price, active properties, strong bactericidal ability and easy production.

[0003] The existing common sodium hypochlorite production process generally adopts the method of tower absorption with a conveying pump circulating alkali solution filler to produce sodium hypochlorite. Usually, low-purity chlorine produced by pressurized chlorine or chlorine liquefaction is used as a raw material to react with a sodium hydroxide solution with a concentration of about 16%. The main reaction equipment in the production adopts a production process of tower circulating alkali solution absorption or tank chlorine bubbling absorption. However, the tower circulating alkali solution absorption process occupies a large area, relies on a circulating alkali pump to continuously cycle and absorb for a long time to prepare sodium hypochlorite, and consumes a lot of power; the tank chlorine bubbling absorption process has a long production cycle, the intermediate process is not easy to monitor, and often causes unqualified finished products or chlorine leakage accidents due to improper operation. In addition, the two existing processes have local overchlorination in the reaction process, and the product quality has a high salt content and is relatively low in quality. Summary of the invention

[0004] 1. Technical issues to be solved

[0005] In view of the deficiencies in the prior art, the present invention provides an energy-saving and consumption-reducing production device and method for sodium hypochlorite, which solves the problems raised in the above-mentioned background technology by optimizing the existing process.

[0006] (II) Technical solution

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0008] According to a first aspect of the present invention, there is provided a sodium hypochlorite energy-saving and consumption-reducing production device, comprising an electrolytic chlorine production unit and an alkali solution configuration unit, wherein the electrolytic chlorine production unit is connected to a chlorine scrubber, and the chlorine scrubber is respectively connected to a falling film absorber and a chlorine cooler through a chlorine pipeline, and the chlorine cooler is connected to a water mist collector, and the water mist collector is connected to a chlorine drying and liquefaction unit, and the chlorine drying and liquefaction unit is connected to a sodium hypochlorite reaction unit;

[0009] The alkali solution configuration unit is connected to the alkali solution high-level tank through an alkali solution delivery pump, the alkali solution high-level tank is connected to the falling film absorber through an alkali solution pipeline, the liquid outlet of the falling film absorber is connected to the sodium hypochlorite reaction unit, and the liquid outlet of the sodium hypochlorite reaction unit is connected to the sodium hypochlorite storage tank through a sodium hypochlorite delivery pump.

[0010] Preferably, the bottom gas outlet of the falling film absorber is connected to the inlet of the titanium fan, and the outlet of the titanium fan is connected to the tail gas accident tower; the titanium fan is also provided with a liquid outlet, and the liquid outlet is connected to the pipeline between the liquid outlet of the falling film absorber and the sodium hypochlorite reaction unit.

[0011] The present invention arranges a titanium fan to suck a small amount of chlorine remaining in a falling film absorber into a tail gas accident tower for dechlorination, and the residual harmful gas is circulated and absorbed by an alkali solution in the tail gas accident tower, and then discharged after reaching a qualified tail gas emission standard; in the process of the titanium fan sucking the residual chlorine under negative pressure, a small amount of a mixed solution of sodium hypochlorite and sodium hydroxide is sucked into the titanium fan, precipitated through a liquid outlet, and then transported to a pipeline between a liquid outlet of the falling film absorber and a sodium hypochlorite reaction unit, and mixed with the mixed solution of sodium hypochlorite and sodium hydroxide flowing out of the falling film absorber, and the residual sodium hydroxide solution is further reacted in the sodium hypochlorite reaction unit.

[0012] Preferably, a flow meter, a regulating valve and a pressure gauge are provided on the chlorine pipeline between the chlorine scrubber and the falling film absorber, and a tube outer jacket is provided on the outside of the falling film absorber to cool the reaction heat in the falling film absorber through condensed water in the tube outer jacket.

[0013] Preferably, a flow meter and a regulating valve are provided on the alkali solution pipeline between the alkali solution high-level tank and the falling film absorber.

[0014] Preferably, the sodium hypochlorite reaction unit comprises a sodium hypochlorite reaction tank I and a sodium hypochlorite reaction tank II connected in parallel, and cooling coils are provided inside the sodium hypochlorite reaction tank I and the sodium hypochlorite reaction tank II.

[0015] Preferably, a regulating valve is provided on the chlorine pipeline between the chlorine drying and liquefaction unit and the sodium hypochlorite reaction unit.

[0016] The present invention arranges a regulating valve, a flow meter, a pressure gauge and other equipment on the raw material conveying pipeline, which can monitor the speed of raw material conveying in real time, avoid the problems of excessive chlorine and sodium hypochlorite decomposition due to too low pH, and thus improve the quality of sodium hypochlorite.

[0017] According to a second aspect of the present invention, there is provided a production method using the above-mentioned sodium hypochlorite energy-saving and consumption-reducing production device, comprising the following steps:

[0018] (1) opening the falling film absorber and controlling the temperature to be 20-40° C., washing the wet chlorine produced by electrolysis through a chlorine washing tower, introducing a portion of the washed wet chlorine into the falling film absorber to react with the alkali solution transported from the alkali solution high-level tank to the falling film absorber, thereby obtaining a mixture containing the alkali solution and sodium hypochlorite, introducing another portion of the washed wet chlorine into a chlorine cooler, a water mist collector, and a chlorine drying and liquefaction unit in sequence for drying, and introducing the dried chlorine into a sodium hypochlorite reaction unit;

[0019] (2) transporting the mixture containing alkali solution and sodium hypochlorite to a sodium hypochlorite reaction unit for secondary reaction with dry chlorine gas to obtain a sodium hypochlorite solution with a free alkali concentration of less than 1%;

[0020] (3) The sodium hypochlorite solution with a free alkali concentration of less than 1% is transferred to a sodium hypochlorite storage tank through a sodium hypochlorite transfer pump for storage.

[0021] Preferably, the flow rate of wet chlorine gas entering the falling film absorber is 300-1000 m 3 / h, the flow rate of alkali solution into the falling film absorber is 3.3~11m 3 / h, and the concentration of the alkali solution is 15-18wt%.

[0022] Preferably, the flow rate of dry chlorine gas introduced into the sodium hypochlorite reaction unit is 300 to 1000 m 3 / h.

[0023] (III) Beneficial effects

[0024] The present invention provides a sodium hypochlorite energy-saving and consumption-reducing production device and production method, which has the following beneficial effects:

[0025] (1) The present invention provides a sodium hypochlorite energy-saving and consumption-reducing production device, in which alkali solution and wet chlorine gas are first subjected to a preliminary reaction in a falling film absorber, and then dry chlorine gas is introduced into the sodium hypochlorite reaction unit to further react with the remaining alkali solution to generate high-quality sodium hypochlorite. The device has a high degree of automation, stable production operation, simple operation when adjusting the production load, and greater operational flexibility.

[0026] (2) The present invention provides a method for producing sodium hypochlorite with energy saving and consumption reduction. The above-mentioned production device is used to directly use the washed wet chlorine gas and alkali solution for preliminary reaction, and then use a small amount of dry chlorine gas for secondary reaction. The remaining chlorine gas from electrolytic chlorine production is then hydraulically collected and stored. On the one hand, the cost of chlorine liquefaction and liquid chlorine storage can be reduced; on the other hand, in the process of preparing sodium hypochlorite, the occurrence of side reactions and chlorination can be reduced, thereby improving the purity and concentration of sodium hypochlorite. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1A schematic diagram of a sodium hypochlorite energy-saving and consumption-reducing production device provided by the present invention.

[0028] Among them, 1. electrolytic chlorine production unit; 2. alkali solution configuration unit; 3. chlorine gas washing tower; 4. falling film absorber; 5. chlorine gas cooler; 6. water mist collector; 7. sodium hypochlorite reaction unit; 8. alkali solution delivery pump; 9. alkali solution high-level tank; 10. sodium hypochlorite delivery pump; 11. sodium hypochlorite storage tank; 12. titanium fan; 13. tail gas accident tower; 14. chlorine gas drying and liquefaction unit; 7-1. sodium hypochlorite reaction tank I; 7-2. sodium hypochlorite reaction tank II. DETAILED DESCRIPTION

[0029] In order to better illustrate the content of the present invention, a detailed description is given below in conjunction with specific embodiments.

[0030] This embodiment provides a sodium hypochlorite energy-saving and consumption-reducing production device, such as Figure 1 As shown, it includes an electrolytic chlorine production unit 1 and an alkali solution configuration unit 2, the electrolytic chlorine production unit 1 is connected to a chlorine scrubber 3, the chlorine scrubber 3 is respectively connected to a falling film absorber 4 and a chlorine cooler 5 through a chlorine pipeline, the chlorine cooler 5 is connected to a water mist collector 6, the water mist collector 6 is connected to a chlorine drying and liquefaction unit 14, and the chlorine drying and liquefaction unit 14 is connected to a sodium hypochlorite reaction unit 7; the alkali solution configuration unit 2 is connected to an alkali solution high-level tank 9 through an alkali solution delivery pump 8, the alkali solution high-level tank 9 is connected to the falling film absorber 4 through an alkali solution pipeline, the liquid outlet of the falling film absorber 4 is connected to the sodium hypochlorite reaction unit 7, and the liquid outlet of the sodium hypochlorite reaction unit 7 is connected to a sodium hypochlorite storage tank 11 through a sodium hypochlorite delivery pump 10.

[0031] In a specific embodiment, the bottom gas outlet of the falling film absorber 4 is connected to the inlet of the titanium fan 12, and the outlet of the titanium fan 12 is connected to the tail gas removal accident tower 13. The titanium fan 12 is also provided with a liquid outlet, and its liquid outlet is connected to the pipeline between the liquid outlet of the falling film absorber 4 and the sodium hypochlorite reaction unit 7. The unreacted residual chlorine in the falling film absorber 4 is transported to the tail gas removal accident tower 13 through the titanium fan 12 to absorb the residual harmful gas and discharge it when it reaches the qualified tail gas standard. A small amount of mixed liquid containing sodium hypochlorite and alkali solution sucked by the titanium fan 12 under negative pressure is partially collected at the bottom of the titanium fan 12 and re-transported to the sodium hypochlorite reaction unit 7 through the liquid outlet at the bottom for reaction.

[0032] In a specific embodiment, a flow meter, a regulating valve and a pressure gauge are provided on the chlorine pipeline between the chlorine scrubbing tower 3 and the falling film absorber 4, and a tube outer jacket is provided outside the falling film absorber 4, so that the reaction heat in the falling film absorber 4 can be cooled by condensed water in the tube outer jacket.

[0033] In a specific embodiment, a flow meter and a regulating valve are provided on the alkali solution pipeline between the alkali solution high-level tank 9 and the falling film absorber 4 .

[0034] The present invention provides flow meters and regulating valves on the chlorine gas pipeline and the alkali solution pipeline leading to the falling film absorber 4, so that the flow rates of the chlorine gas and the alkali solution entering the falling film absorber can be regulated in real time, the concentration of sodium hypochlorite can be increased, and the emission of excess chlorine can be reduced.

[0035] In a specific embodiment, the sodium hypochlorite reaction unit 7 includes a sodium hypochlorite reaction tank I7-1 and a sodium hypochlorite reaction tank II7-2 connected in parallel, and cooling coils are provided inside the sodium hypochlorite reaction tank I7-1 and the sodium hypochlorite reaction tank II7-2. Through the sodium hypochlorite reaction tank I7-1 and the sodium hypochlorite reaction tank II7-2 connected in parallel, the unreacted alkali solution in the falling film absorber 4 can be further reacted with dry chlorine to increase the concentration of sodium hypochlorite.

[0036] In a specific embodiment, a regulating valve is provided on the chlorine pipeline between the chlorine drying and liquefaction unit 14 and the sodium hypochlorite reaction unit 7, which can adjust the content of the dry chlorine gas introduced to avoid overchlorination reaction.

[0037] In the present invention, part of the chlorine generated by the electrolytic chlorine production unit 1 is directly transported to the falling film absorber 4 through the chlorine scrubber 3 for reaction, and part of it is dried through the chlorine cooler 5, the water mist collector 6 and the chlorine drying and liquefaction unit 14, and then transported to the sodium hypochlorite reaction unit 7 for reaction. Through this device, not only the quality of sodium hypochlorite is improved, but also the amount of liquid chlorine is reduced, which can reduce the potential accidents caused by the storage, filling and road transportation of liquid chlorine.

[0038] The preparation process of sodium hypochlorite using the above-mentioned sodium hypochlorite energy-saving and consumption-reducing production device is as follows:

[0039] (1) The falling film absorber 4 is turned on and the temperature is controlled to be 30° C. The chlorine gas generated by electrolysis in the electrolytic chlorine production unit 1 is first washed by the chlorine washing tower 3. A part of the wet chlorine gas after washing is introduced into the falling film absorber 4 to react with the alkali solution transported from the alkali solution high temperature tank 9 to the falling film absorber 4 to obtain a mixture containing alkali solution and sodium hypochlorite. The flow rate of the chlorine gas is adjusted to 1000 m / s. 3 / h, the flow rate of alkali solution is 11m 3 / h, the alkali solution in this embodiment is a sodium hydroxide solution, wherein the concentration of the sodium hydroxide solution is 16wt%;

[0040] (2) After being washed by the chlorine scrubber 3, another part of the wet chlorine is successively introduced into the chlorine cooler 5 and the water mist collector 6 for drying. The dried chlorine is introduced into the sodium hypochlorite reaction unit 7, and the flow rate of the dry chlorine is adjusted to 30m 3 / h to conduct secondary reaction with the mixture containing sodium hypochlorite and alkali solution outputted from the falling film absorber 4 to obtain a sodium hypochlorite solution having a free alkali concentration of less than 1%;

[0041] (3) If the dry chlorine gas required in the sodium hypochlorite reaction unit 7 is insufficient, the remaining dry chlorine gas after drying in the water mist collector 6 enters the liquid chlorine storage unit 14 for hydraulic storage;

[0042] (4) The obtained sodium hypochlorite solution with a free alkali concentration of less than 1% is transported to a sodium hypochlorite storage tank 11 by a sodium hypochlorite delivery pump 10 for storage.

[0043] The present embodiment adopts the sodium hypochlorite energy-saving and consumption-reducing production device, the power consumption is reduced, the amount of sulfuric acid in the water mist trap of wet chlorine is reduced, and a large amount of cost is saved. After calculation, the sodium hypochlorite with a preparation concentration of 10% can save about 50 yuan per ton in running cost. In addition, the automation degree of this device is high, the product quality is stable, the production flexibility is large, it has very efficient operability, and can reduce the potential accidents and product quality problems caused by operating errors. The concentration of the product can also be adjusted according to demand. The dynamic equipment used is less, the hypochlorite delivery pump selects a magnetic pump, and the seal of the titanium blower adopts positive pressure compressed air protection, which can avoid material leakage in the production process and reduce pollution to the atmosphere and the environment.

[0044] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A sodium hypochlorite energy-saving and consumption-reducing production device, comprising an electrolytic chlorine production unit and an alkali solution configuration unit, characterized in that: The electrolytic chlorine production unit is connected to a chlorine scrubber, the chlorine scrubber is connected to a falling film absorber and a chlorine cooler through a chlorine pipeline, the chlorine cooler is connected to a water mist collector, the water mist collector is connected to a chlorine drying and liquefaction unit, and the chlorine drying and liquefaction unit is connected to a sodium hypochlorite reaction unit; The alkali solution configuration unit is connected to the alkali solution high-level tank through an alkali solution delivery pump, the alkali solution high-level tank is connected to the falling film absorber through an alkali solution pipeline, the liquid outlet of the falling film absorber is connected to the sodium hypochlorite reaction unit, and the liquid outlet of the sodium hypochlorite reaction unit is connected to the sodium hypochlorite storage tank through a sodium hypochlorite delivery pump.

2. A sodium hypochlorite energy-saving and consumption-reducing production device according to claim 1, characterized in that: The bottom gas outlet of the falling film absorber is connected to the inlet of the titanium fan, and the outlet of the titanium fan is connected to the tail gas accident tower; the titanium fan is also provided with a liquid outlet, and the liquid outlet is connected to the pipeline between the liquid outlet of the falling film absorber and the sodium hypochlorite reaction unit.

3. A sodium hypochlorite energy-saving and consumption-reducing production device according to claim 1, characterized in that: A flow meter, a regulating valve and a pressure gauge are arranged on the chlorine pipeline between the chlorine scrubber and the falling film absorber. A tube outer jacket is arranged outside the falling film absorber to cool the reaction heat in the falling film absorber through condensed water in the tube outer jacket.

4. A sodium hypochlorite energy-saving and consumption-reducing production device according to claim 1, characterized in that: A flow meter and a regulating valve are arranged on the alkali liquid pipeline between the alkali liquid high-level tank and the falling film absorber.

5. A sodium hypochlorite energy-saving and consumption-reducing production device according to claim 1, characterized in that: The sodium hypochlorite reaction unit comprises a sodium hypochlorite reaction tank I and a sodium hypochlorite reaction tank II connected in parallel, and cooling coils are arranged inside the sodium hypochlorite reaction tank I and the sodium hypochlorite reaction tank II.

6. A sodium hypochlorite energy-saving and consumption-reducing production device according to claim 1, characterized in that: A regulating valve is provided on the chlorine pipeline between the chlorine drying and liquefaction unit and the sodium hypochlorite reaction unit.

7. A production method using the sodium hypochlorite energy-saving and consumption-reducing production device according to any one of claims 1 to 6, characterized in that: The following steps are involved: (1) opening the falling film absorber and controlling the temperature to be 20-40° C., washing the wet chlorine produced by electrolysis through a chlorine washing tower, introducing a portion of the washed wet chlorine into the falling film absorber to react with the alkali solution transported from the alkali solution high level tank to the falling film absorber, thereby obtaining a mixture containing the alkali solution and sodium hypochlorite, introducing another portion of the washed wet chlorine into a chlorine cooler, a water mist collector and a chlorine drying and liquefaction unit in sequence for drying, and introducing the dried chlorine into a sodium hypochlorite reaction unit; (2) transporting the mixture containing alkali solution and sodium hypochlorite to a sodium hypochlorite reaction unit for secondary reaction with dry chlorine gas to obtain a sodium hypochlorite solution with a free alkali concentration of less than 1%; (3) The sodium hypochlorite solution with a free alkali concentration of less than 1% is transferred to a sodium hypochlorite storage tank through a sodium hypochlorite transfer pump for storage.

8. The energy-saving and consumption-reducing production method of sodium hypochlorite according to claim 7, characterized in that: The flow rate of wet chlorine gas into the falling film absorber is 300~1000m 3 / h, the flow rate of alkali solution into the falling film absorber is 3.3~11m 3 / h, and the concentration of the alkali solution is 15-18wt%.

9. The energy-saving and consumption-reducing production method of sodium hypochlorite according to claim 7, characterized in that: The flow rate of dry chlorine gas introduced into the sodium hypochlorite reaction unit is 300-1000m 3 / h.

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