Chloromethane byproduct sulfuric acid decolorizing device

Abstract

The utility model discloses a chloromethane byproduct sulfuric acid decolorizing device which comprises a sulfuric acid storage tank and a chlorine water storage tank, the sulfuric acid storage tank and the chlorine water storage tank are both communicated with a mixer arranged at the downstream and are used for mixing and diluting the sulfuric acid storage tank and the chlorine water storage tank, the mixer is communicated with a blow-off tank arranged at the downstream, and the upper parts of the mixer and the blow-off tank are communicated with a tail gas treatment device. And a filter is arranged at the downstream of the blow-off tank to filter insoluble substances and then enters a dilute sulphuric acid storage tank at the downstream. The chloromethane byproduct sulfuric acid and the chlorine water are mixed and diluted, coloring organic matters in the sulfuric acid are oxidized and faded by free chlorine through the chlorine water, residual chlorine in the dilute sulfuric acid is blown out through compressed air, a colorless and odorless dilute sulfuric acid solution is obtained, and the decolorizing device is simple in equipment, simple in process flow and low in operation cost.

Description

Technical Field

[0001] The utility model belongs to the technical field of sulfuric acid purification, and in particular relates to a device for decolorizing methyl chloride by-product sulfuric acid. Background Art

[0002] The methanol-based chloromethane production process requires concentrated sulfuric acid to dehydrate and dry chloromethane, and chloromethane, water, and by-product dimethyl ether will enter the sulfuric acid. Due to the presence of organic matter, the by-product dilute sulfuric acid of chloromethane is red or brown in color and has a strong odor, which seriously affects its secondary use.

[0003] Publication No. CN109052336A discloses a purification and concentration device and process for dilute sulfuric acid produced as a byproduct of methyl chloride drying. The device uses a vacuum evaporation and concentration method to remove a large amount of organic matter, but hydrogen peroxide still needs to be added for complete decolorization. The equipment is complex and energy consumption is high. At the same time, the residual hydrogen peroxide poses a safety hazard to subsequent use.

[0004] At the same time, publication number CN103172033A discloses a method for decolorizing sulfuric acid, in which diluted sulfuric acid is introduced into oxygen at high temperature in a sealed space to cause oxidation and decolorization. However, the corrosion of sulfuric acid to equipment at high temperature must be considered, and oxygen must be used, which has high equipment requirements and poor economic efficiency.

[0005] Therefore, there is an urgent need to provide a chloromethane byproduct sulfuric acid decolorization device with simple equipment and low operating cost. Utility Model Content

[0006] In view of the above-mentioned shortcomings, the purpose of the utility model is to provide a chloromethane by-product sulfuric acid decolorization device, which solves the problems of high equipment requirements, complex process and high operating cost in the prior art for the chloromethane by-product sulfuric acid decolorization process.

[0007] In order to achieve the above purpose, the technical solution provided by the utility model is:

[0008] A device for decolorizing methyl chloride with byproduct sulfuric acid comprises a sulfuric acid storage tank and a chlorine water storage tank. Both the sulfuric acid storage tank and the chlorine water storage tank are connected to a mixer arranged downstream and are mixed and diluted for reaction. The mixer is connected to a blow-off tank arranged downstream, and the tops of the mixer and the blow-off tank are connected to an exhaust gas treatment device. A filter is arranged downstream of the blow-off tank to filter out insoluble matter before the matter enters a dilute sulfuric acid storage tank downstream.

[0009] By adopting the above structural design, in the chlor-alkali chemical production, the ion membrane caustic soda production process will produce a certain amount of chlorine water (aqueous solution of chlorine gas), which has good oxidation decolorization performance. Sulfuric acid and chlorine water are mixed and diluted, and the colored organic matter in the sulfuric acid is oxidized and decolorized by free chlorine through the chlorine water, and then the residual chlorine in the dilute sulfuric acid is blown out by compressed air to obtain a colorless and odorless dilute sulfuric acid solution. The decolorization device is simple in equipment, and at the same time, the chlorine water produced as a by-product in the ion membrane caustic soda production process is used as a dilution and decolorization raw material, which further reduces the cost of decolorization.

[0010] As a further improvement, the lower end of the mixer is connected to the sulfuric acid storage tank and the chlorine water storage tank to inject sulfuric acid and chlorine water for mixing respectively, and the upper end is provided with an overflow port connected to the blow-off tank through a pipeline to allow the diluted sulfuric acid after the dilution reaction to enter the blow-off tank.

[0011] As a further improvement, the blow-off tank is designed as a double-layer structure with an isolation barrel inside. A through hole is opened at the lower end of the isolation barrel to communicate with the external blow-off tank. The pipe connected to the overflow port of the mixer extends into the isolation barrel. An overflow port is provided at the upper end of the blow-off tank to communicate with the filter through a pipe.

[0012] With the above structural design, the blow-off tank adopts a double-layer design. After the diluted sulfuric acid enters the internal isolation barrel, the residual chlorine is blown out by air. The sulfuric acid before and after the blowing can be isolated, which can improve the residual chlorine removal efficiency.

[0013] As a further improvement, the blow-off tank is externally connected to compressed air, and the compressed air is connected through a blow pipe, and the blow pipe is arranged at the bottom of the blow-off tank, and a plurality of upward air jets are arranged at the end thereof.

[0014] By adopting the above structural design, the residual chlorine in the sulfuric acid can be blown off from bottom to top, thereby improving the blowing off efficiency and reducing the content of free chlorine in the sulfuric acid.

[0015] As a further improvement, the tail gas treatment device includes a tail gas treatment tower and an activated carbon adsorber. A spray component is arranged in the tail gas treatment tower to spray the tail gas with liquid alkali to absorb free chlorine and part of the organic gas.

[0016] With the above structural design, the liquid alkali, free chlorine and part of the organic gas are sprayed and absorbed in the tail gas treatment tower, and then further absorbed by the activated carbon adsorber, and the discharged tail gas is a colorless and odorless gas.

[0017] As a further improvement, a receiving tank is provided between the blow-off tank and the filter for transferring the dilute sulfuric acid, and the dilute sulfuric acid is pumped into the filter for filtration by a booster pump.

[0018] By adopting the above structural design, insoluble matter can be filtered, thereby improving the quality of secondary use of dilute sulfuric acid.

[0019] As a further improvement, the pipes connecting the sulfuric acid storage tank and the chlorine water storage tank with the mixer are both provided with metering pumps to meter the mixed sulfuric acid and chlorine water.

[0020] By adopting the above structural design, the specific concentration of sulfuric acid dilution can be guaranteed, and the original concentration of sulfuric acid of 86% can be diluted to 50%.

[0021] A method for decolorizing methyl chloride by-product sulfuric acid is also provided, comprising the following steps:

[0022] S1. Inject the measured sulfuric acid and chlorine water into the sulfuric acid storage tank and the chlorine water storage tank respectively from the lower end, and then inject them into the mixer for mixing. The coloring matter in the chlorine water and sulfuric acid reacts with the chlorine water to fade, and releases heat in the mixer, and the temperature in the mixer needs to be controlled not to be greater than 50 degrees;

[0023] S2, after the sulfuric acid is diluted and decolorized in the mixer, it overflows from the upper end into the blow-off tank, and the chlorine is blown off by external compressed air. The free chlorine and part of the organic gas discharged from the top of the mixer and the blow-off tank enter the tail gas treatment device for treatment and then discharged;

[0024] S3. After the free chlorine and part of the organic gas are blown out of the sulfuric acid in the blow-off tank, the insoluble matter is filtered through a filter and finally enters the dilute sulfuric acid storage tank for storage for future use.

[0025] As a further improvement, the exhaust gas treatment device for treating the exhaust gas in step S2 includes an exhaust gas treatment tower and an activated carbon adsorber. Liquid alkali is circulated in the exhaust gas treatment tower to absorb free chlorine and part of the organic gas, and then enters the activated carbon adsorber to further absorb the organic gas and discharge colorless and odorless gas.

[0026] As a further improvement, in step S2, after compressed air is used to blow out part of the free chlorine dissolved in the dilute sulfuric acid in the blow-off tank, the free chlorine in the dilute sulfuric acid is less than 30 ppm.

[0027] Compared with the prior art, the beneficial effects of the utility model are:

[0028] 1. The utility model mixes and dilutes sulfuric acid produced as a byproduct of methyl chloride and chlorine water, oxidizes and decolorizes the colored organic matter in the sulfuric acid by free chlorine through the chlorine water, and then blows out the residual chlorine in the dilute sulfuric acid through compressed air to obtain a colorless and odorless dilute sulfuric acid solution. The decolorization device has simple equipment, simple process flow and low operating cost;

[0029] 2. The blow-off tank described in the utility model is a double-layer structure design, with an isolation barrel inside. A through hole is opened at the lower end of the isolation barrel to communicate with the external blow-off tank. After the diluted sulfuric acid enters the internal isolation barrel, the residual chlorine is blown off by air in the blow-off tank. The double-layer structure design can isolate the sulfuric acid before and after the blow-off, which can improve the residual chlorine removal efficiency;

[0030] 3. The utility model further reduces the decolorization cost of sulfuric acid by utilizing chlorine water produced in the production process of ion membrane caustic soda as a dilution and decolorization raw material in existing production. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention, but do not constitute a limitation to the present invention. In the accompanying drawings:

[0032] Figure 1 It is a schematic diagram of the structure of Embodiment 1 of the present utility model;

[0033] Figure 2 It is a schematic diagram of the structure of the blow-off tank in Example 2 of the utility model.

[0034] In the figure:

[0035] Sulfuric acid storage tank 1, chlorine water storage tank 2, mixer 3, blow-off tank 4, tail gas treatment device 5, tail gas treatment tower 5a, activated carbon adsorber 5b, spray assembly 5c, filter 6, dilute sulfuric acid storage tank 7, isolation barrel 8, blow pipe 9, jet nozzle 9a, receiving tank 10, booster pump 11, metering pump 12. DETAILED DESCRIPTION

[0036] In order to explain the technical content, structural features, achieved objectives and effects of the present invention in detail, the following is a detailed description in conjunction with the implementation modes and the accompanying drawings.

[0037] The technical solution of the utility model will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the utility model, rather than all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model. In the description of the utility model, it should be noted that the orientation or position relationship indicated by the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the utility model.

[0038] Example 1

[0039] See also Figure 1 , a chloromethane byproduct sulfuric acid decolorization device, comprising a sulfuric acid storage tank 1 and a chlorine water storage tank 2, both of which are connected to a mixer 3 arranged downstream and mix and dilute the colored organic matter in the reaction-oxidized sulfuric acid. A metering pump 12 is provided on the pipelines connecting the sulfuric acid storage tank 1 and the chlorine water storage tank 2 with the mixer 3 to meter the mixed sulfuric acid and chlorine water. The mixer 3 is connected to a blow-off tank 4 arranged downstream, and the mixer 3 and the blow-off tank 4 are connected to an exhaust gas treatment device 5 above. A filter 6 is provided downstream of the blow-off tank 4 to filter out insoluble matter and then enter the downstream dilute sulfuric acid storage tank 7. In this embodiment, the position direction of the sulfuric acid storage tank 1 and the chlorine water storage tank 2 is defined as the upstream direction.

[0040] In this embodiment, the lower end of the mixer 3 is connected with the sulfuric acid storage tank 1 and the chlorine water storage tank 2, and sulfuric acid and chlorine water are injected and mixed respectively. The upper end is provided with an overflow port, which is connected with the blow-off tank 4 through a pipeline, and the dilute sulfuric acid after the dilution reaction enters the blow-off tank 4. The mixer 3 enters the mixed liquid from the lower end, and after sufficient reaction, it is discharged from the upper overflow port into the blow-off tank 4. The blow-off tank 4 is connected to compressed air, and the compressed air is connected through a blow pipe 9, and the blow pipe 9 is arranged at the bottom of the blow-off tank 4, and the end is provided with a plurality of upward jets 9a. After compressed air is blown into the dilute sulfuric acid to remove free chlorine, it is discharged from the top and enters the tail gas treatment device 5. After being processed by this process, the free chlorine of the dilute sulfuric acid is lower than 30ppm, which can reduce the free chlorine by about 70ppm to meet the subsequent recycling of the dilute sulfuric acid.

[0041] The tail gas treatment device 5 comprises a tail gas treatment tower 5a and an activated carbon adsorber 5b. A spray component 5c is arranged inside the tail gas treatment tower 5a to spray the tail gas with liquid alkali to absorb free chlorine and part of organic gas, which is then further absorbed by the activated carbon adsorber 5b and then discharged. The discharged air is colorless, odorless and pollution-free.

[0042] Furthermore, a receiving tank 10 is provided between the blow-off tank 4 and the filter 6 for transferring the dilute sulfuric acid, and the dilute sulfuric acid is pumped into the filter 6 for filtration via a booster pump 11 .

[0043] A method for decolorizing methyl chloride by-product sulfuric acid is also provided, comprising the following steps:

[0044] S1, inject the measured sulfuric acid and chlorine water into the sulfuric acid storage tank 1 and the chlorine water storage tank 2 from the lower end respectively, and then inject them into the mixer 3 for mixing, the coloring matter in the chlorine water and sulfuric acid reacts with the chlorine water to fade, and releases heat in the mixer 3, and the temperature in the mixer 3 needs to be controlled not to be greater than 50 degrees;

[0045] S2, the sulfuric acid is diluted and decolorized in the mixer 3, and then overflows from the upper end into the blow-off tank 4, and the chlorine is blown off by external compressed air. After the free chlorine dissolved in the sulfuric acid in the dilute sulfuric acid in the blow-off tank 4 is blown out by compressed air, the free chlorine in the dilute sulfuric acid is less than 30ppm. The free chlorine and part of the organic gas discharged from the top of the mixer 3 and the blow-off tank 4 enter the tail gas treatment device 5 for treatment and then discharge; wherein, the free chlorine and part of the organic gas are absorbed and treated by circulating the liquid alkali in the tail gas treatment tower 5a, and then enter the activated carbon adsorber 5b to further absorb the organic gas, and discharge colorless and odorless gas.

[0046] S3, the sulfuric acid after the free chlorine and part of the organic gas are blown out by the blow-off tank 4 is filtered for insoluble matter by the filter 6, and finally enters the dilute sulfuric acid storage tank 7 for storage for future use.

[0047] Example 2

[0048] See also Figure 2 The other structures of the decolorization device in this embodiment are the same as those in Embodiment 1, except that the blow-off tank 4 is a double-layer structure, with an isolation barrel 8 provided inside, a through hole provided at the lower end of the isolation barrel 8 to communicate with the external blow-off tank 4, a pipe connected to the overflow port of the mixer 3 extends into the isolation barrel 8, and an overflow port is provided at the upper end of the blow-off tank 4 to communicate with the filter 6 through a pipe. The double-layer structure design can effectively isolate the liquid before and after the blow-off of free chlorine, thereby improving the blow-off effect of free chlorine.

[0049] The working principle of the utility model is as follows:

[0050] After measuring the sulfuric acid and chlorine water in the sulfuric acid storage tank 1 and the chlorine water storage tank 2, they are injected into the mixer 3 in proportion for mixing. During mixing, the chlorine water reacts with the colored organic matter in the sulfuric acid, and the organic matter is reacted to make it fade. After fading and dilution, the sulfuric acid contains a certain amount of free chlorine. At this time, the dilute sulfuric acid enters the blow-off tank 4, and a part of the free chlorine dissolved in the dilute sulfuric acid in the blow-off tank 4 is blown off by compressed air and enters the tail gas treatment device 5. The free chlorine in the dilute sulfuric acid treated by the blow-off tank 4 is lower than 30ppm, which can meet the subsequent recycling and is colorless and tasteless. The tail gas discharged from the mixer 3 and the blow-off tank 4 enters the tail gas treatment device 5 and is absorbed by the alkali spray in the tail gas treatment tower 5a. The activated carbon adsorber 5b adsorbs and absorbs and discharges colorless and tasteless gas. At the same time, the dilute sulfuric acid treated by the blow-off tank 4 enters the filter 6 to filter the insoluble matter and enters the dilute sulfuric acid storage tank 7 for standby.

[0051] See also Figure 1 , Figure 2The decolorization device used in the utility model adopts a sulfuric acid storage tank 1, a chlorine water storage tank 2, a mixer 3, a blow-off tank 4, a tail gas treatment device 5, a filter 6 and a dilute sulfuric acid storage tank 7 to complete the decolorization of sulfuric acid produced by methyl chloride. The equipment is simple and the equipment cost is low. At the same time, the process method adopted is simple. The chlorine water used as the decolorization raw material comes from the ion membrane caustic soda production process, which will produce a certain amount of chlorine water (chlorine gas aqueous solution), which has good oxidation decolorization performance. Therefore, the operating cost is greatly reduced.

[0052] According to the disclosure and teaching of the above specification, the technicians in the field of the utility model can also change and modify the above implementation. Therefore, the utility model is not limited to the specific implementations disclosed and described above, and some modifications and changes to the utility model should also fall within the protection scope of the claims of the utility model. In addition, although some specific terms are used in this specification, these terms are only for the convenience of description and do not constitute any limitation to the utility model. Other devices that are the same or similar to them are all within the protection scope of the utility model.

Claims

1. A chloromethane by-product sulfuric acid decolorization device, characterized in that: The invention comprises a sulfuric acid storage tank (1) and a chlorine water storage tank (2), wherein the sulfuric acid storage tank (1) and the chlorine water storage tank (2) are both connected to a mixer (3) arranged downstream and are mixed, diluted and reacted, the mixer (3) is connected to a blow-off tank (4) arranged downstream, and the tops of the mixer (3) and the blow-off tank (4) are connected to an exhaust gas treatment device (5), and a filter (6) is arranged downstream of the blow-off tank (4) to filter out insoluble matter and then enter a downstream dilute sulfuric acid storage tank (7).

2. A chloromethane by-product sulfuric acid decolorization device as claimed in claim 1, characterized in that: The lower end of the mixer (3) is connected to the sulfuric acid storage tank (1) and the chlorine water storage tank (2) to inject sulfuric acid and chlorine water into the mixture respectively. The upper end is provided with an overflow port which is connected to the blow-off tank (4) through a pipeline, so that the diluted sulfuric acid after the dilution reaction enters the blow-off tank (4).

3. A chloromethane by-product sulfuric acid decolorization device as claimed in claim 2, characterized in that: The blow-off tank (4) is designed as a double-layer structure, with an isolation barrel (8) provided inside. A through hole is provided at the lower end of the isolation barrel (8) to communicate with the external blow-off tank (4). A pipe connected to the overflow port of the mixer (3) extends into the isolation barrel (8). An overflow port is provided at the upper end of the blow-off tank (4) to communicate with the filter (6) through a pipe.

4. A chloromethane by-product sulfuric acid decolorization device as claimed in claim 2 or 3, characterized in that: The blow-off tank (4) is connected to compressed air via a blow pipe (9), and the blow pipe (9) is arranged at the bottom of the blow-off tank (4), and a plurality of upward jet ports (9a) are arranged at the end thereof.

5. A chloromethane by-product sulfuric acid decolorization device as claimed in claim 1, characterized in that: The tail gas treatment device (5) comprises a tail gas treatment tower (5a) and an activated carbon adsorber (5b). The tail gas treatment tower (5a) is provided with a spray component (5c) for spraying the tail gas with liquid alkali to absorb free chlorine and part of the organic gas.

6. A chloromethane by-product sulfuric acid decolorization device as claimed in claim 1, characterized in that: A receiving tank (10) is provided between the blow-off tank (4) and the filter (6) for transferring the dilute sulfuric acid, and the dilute sulfuric acid is pumped into the filter (6) for filtration via a booster pump (11).

7. A chloromethane by-product sulfuric acid decolorization device as claimed in claim 1, characterized in that: The pipes connecting the sulfuric acid storage tank (1) and the chlorine water storage tank (2) with the mixer (3) are both provided with metering pumps (12) for metering the mixed sulfuric acid and chlorine water.

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