High-salinity wastewater mother liquor recycling device and process method

Abstract

The invention belongs to the technical field of mother liquor recovery, and particularly relates to a high-salinity wastewater mother liquor recycling device and process method. The process method comprises the following steps: S1, adding mother liquor into an alkaline hydrolysis kettle, then adding liquid potassium hydroxide, and carrying out alkaline hydrolysis reaction; the non-condensable gas enters an ammonia recovery tower, and dimethylamine and ammonia are recovered; s2, detecting the content of dimethylformamide and dimethylamine hydrochloride in the alkaline hydrolyzed material, and executing the step S3 after the content of dimethylformamide and dimethylamine hydrochloride is smaller than the set content; otherwise, continuously adding the liquid potassium hydroxide until the content is less than the set content; s3, after alkaline hydrolysis is completed, evaporating to remove ammonia / amine; and S4, feeding the ammonia / amine water saturated by adsorption to a dimethylamine rectifying tower recovery device, and separating to obtain liquid dimethylamine and ammonia water. According to the device, an alkaline hydrolysis kettle is connected with a condenser I, the condenser I is connected with an ammonia recovery tower, and the ammonia recovery tower is connected with a dimethylamine rectifying tower recovery device. According to the method, mother liquor recycling is realized, and the mother liquor recycling cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of mother liquor recovery, and specifically relates to a high-salt wastewater mother liquor resource recovery device and a process method. Background Art

[0002] Dimethylamine exists in the form of gas at room temperature and has an ammonia-like odor. Its relative density is 0.680 (0°C), melting point is -96°C, and boiling point is 7.4°C. It is easily soluble in water, ethanol, and ether. It is easily flammable and weakly alkaline. It forms water-soluble salts with inorganic acids. It is used as a raw material for making drugs, dyes, pesticides, and rubber vulcanization accelerators.

[0003] The production process of sucralose produces a large amount of industrial extraction wastewater, the ammonia nitrogen value of which is about 20,000 to 60,000 (N, mg / L), and the main sources of ammonia nitrogen are dimethylamine hydrochloride and dimethylformamide (DMF). Due to the high solubility of dimethylamine hydrochloride and dimethylformamide in water, their recovery is greatly difficult, and the direct recovery cost is high, which increases the production cost of sucralose.

[0004] At present, the treatment method for this type of wastewater is usually to use advanced oxidation method for pretreatment, and then mix it with other low-concentration wastewater before entering the biochemical system. Not only does it require high operating and treatment costs, but it is also impossible to recycle the useful substances in it, resulting in great waste. Summary of the invention

[0005] In order to solve the above technical problems, namely, the waste of material resources of industrial extraction wastewater and the high cost of resource recovery, the present invention provides the following technical solutions:

[0006] In a first aspect, the present invention provides:

[0007] A process for recycling high-salt wastewater mother liquor, comprising the following steps:

[0008] Step S1, alkaline hydrolysis: after adding sucralose MVR mother liquor into the alkaline hydrolysis kettle according to a preset ratio, liquid potassium hydroxide is added into the alkaline hydrolysis kettle, mixed evenly, heated, and alkaline hydrolysis reaction is carried out; during the alkaline hydrolysis reaction, the gas phase is condensed, the condensed water is fully refluxed into the alkaline hydrolysis kettle, and the condensed gas enters the ammonia recovery tower for absorption and then recovers the dimethylamine and ammonia in the gas;

[0009] Step S2, sampling and analysis after the alkaline hydrolysis reaction is completed, detecting the content of dimethylformamide and dimethylamine hydrochloride in the material remaining in the alkaline hydrolysis kettle after alkaline hydrolysis, and executing step S3 after the mass concentrations of dimethylformamide and dimethylamine hydrochloride are both less than the set content; otherwise, continue to add liquid potassium hydroxide, and extend the alkaline hydrolysis reaction time of step S1 until the mass concentrations of dimethylformamide and dimethylamine hydrochloride are both less than the set content;

[0010] Step S3, evaporation and deamination / amine: after the alkaline hydrolysis is completed, the deamination / amine is evaporated, the water of the sucralose MVR mother liquor in the alkaline hydrolysis kettle is evaporated completely, the gas after the alkaline hydrolysis is sent to the condenser for condensation, the condensate is refluxed to the alkaline hydrolysis kettle within a preset first time period, and is replenished to the ammonia recovery tower within a preset second time period, the non-condensable gas is sent to the ammonia recovery tower, and the dimethylamine in the non-condensable gas and the ammonia absorb the condensate;

[0011] Step S4, amine refining: the adsorption saturated amine / ammonia water is sent to a dimethylamine distillation tower recovery device, and liquid dimethylamine and ammonia water are separated by the dimethylamine distillation tower recovery device.

[0012] Furthermore, it also includes:

[0013] Step S5, dissolving: adding pure water to the sucralose MVR mother liquor after evaporation and deamination, stirring to dissolve and dilute the material;

[0014] A small amount of waste gas volatilized during the dissolution process is sent to condenser 1 through a pipeline, and the condensate is pumped into the condensate recovery tank through the gas-liquid separation tank, and the non-condensable gas enters the ammonia recovery tower through hydraulic injection;

[0015] Step S6, neutralization: the dissolved sucralose MVR mother liquor is alkaline, water is added to the alkaline hydrolysis kettle to dilute and dissolve, and then 35% hydrochloric acid is added to adjust the pH to neutral;

[0016] Step S7, filter pressing: After neutralization, powdered activated carbon is added to the alkaline hydrolysis kettle, and the insoluble solids in the sucralose MVR mother liquor are separated by filter pressing, and the potassium-rich organic liquid is obtained by dissolving, neutralizing and filter pressing.

[0017] Furthermore, it also includes:

[0018] Step S8, ammonia recovery tower waste gas treatment:

[0019] The tail gas from the ammonia recovery tower is sent to the water absorption tower for absorption by the first absorbent, the first absorbent is pure water, and the absorption liquid after absorbing the tail gas from the ammonia recovery tower flows back to the ammonia recovery tower to participate in absorption;

[0020] The tail gas from the water absorption tower enters the dilute hydrochloric acid absorption tower and is further absorbed by the second absorbent, which is 5% dilute hydrochloric acid;

[0021] The tail gas from the dilute hydrochloric acid absorption tower is pre-treated by water washing, and then discharged by incineration in the RTO furnace;

[0022] The waste water from the dilute hydrochloric acid absorption tower is returned to the alkaline hydrolysis kettle to continue alkaline hydrolysis to recover gaseous dimethylamine and ammonia.

[0023] In a second aspect, the present invention provides:

[0024] A high-salinity wastewater mother liquor resource recovery device comprises: an alkaline hydrolysis kettle, the alkaline hydrolysis kettle is a jacketed reactor, the top of the alkaline hydrolysis kettle is connected with an elevated tank through a pipeline, a gas phase pipeline and a liquid phase pipeline are arranged between the top of the alkaline hydrolysis kettle and a condenser, the condenser is directly connected with an ammonia recovery tower through the gas phase pipeline, and a dimethylamine rectification tower recovery device is connected to the rear end of the ammonia recovery tower; after the gas phase in the alkaline hydrolysis kettle is cooled in the condenser, the condensate flows back to the alkaline hydrolysis kettle through the liquid phase pipeline, the non-condensable gas goes to the rear end ammonia recovery tower, the ammonia recovery tower absorbs and recovers dimethylamine and ammonia, and the dimethylamine rectification tower recovery device separates the dimethylamine and ammonia recovered by the ammonia recovery tower, and finally obtains liquid dimethylamine and ammonia water.

[0025] Furthermore, a matching gas-liquid separation tank is connected to the bottom of condenser one, and the gas-liquid separation tank is connected to the ammonia recovery tower through a liquid phase pipeline. A condensed water recovery tank is arranged between the gas-liquid separation tank and the ammonia recovery tower. The gas phase in the alkaline hydrolysis kettle is first condensed by condenser one and refluxed into the alkaline hydrolysis kettle, and then enters the gas-liquid separation tank after condensation by condenser one. The liquid in the gas-liquid separation tank is sent to the condensed water recovery tank, and then the condensed liquid is replenished to the ammonia recovery tower by the condensed water recovery tank.

[0026] Further, the dimethylamine distillation tower recovery device comprises:

[0027] An intermediate storage tank, which is connected to the ammonia recovery tower through a pipeline and is used to store adsorption-saturated amine / ammonia recovered by the ammonia recovery tower;

[0028] A deamination tower, the intermediate storage tank is connected to a deamination tower, and the deamination tower is used to remove ammonia / amines from water;

[0029] A dimethylamine distillation tower, wherein the deamination tower is connected to the dimethylamine distillation tower through a pipeline to distill dimethylamine;

[0030] Condenser 2, the dimethylamine distillation tower is connected to condenser 2 through a pipeline, and the dimethylamine after distillation is separated into gas and liquid through condenser 2;

[0031] The reflux tank is connected to the condenser 2 through a pipeline, and the condensed liquid dimethylamine is refluxed to the reflux tank to finally obtain the refined liquid dimethylamine.

[0032] Further, the dimethylamine distillation tower recovery device comprises:

[0033] Condenser 3, the deamination tower is connected to condenser 3 through a pipeline, the gas phase after the deamination tower is sent to condenser 3, and the condensate after cooling by condenser 3 flows back to the deamination tower;

[0034] Ammonia absorption tower: Condenser three is connected to the ammonia absorption tower through a pipeline, and the non-condensable gas of condenser three is sent to the ammonia absorption tower. Pure water is added to the ammonia absorption tower to obtain ammonia water.

[0035] Furthermore, the high-salinity wastewater mother liquor resource recovery device includes:

[0036] Vacuum loader: the bottom of the alkaline hydrolysis kettle is connected to a vacuum loader, and the vacuum loader has a built-in bag dust collector; plate and frame filter press: the bottom of the alkaline hydrolysis kettle is connected to the plate and frame filter press through a pipeline; activated carbon is added to the plate and frame filter press through the vacuum loader, and after the activated carbon absorbs the insoluble solids in the sucralose MVR mother liquor, the materials in the alkaline hydrolysis kettle are transported to the plate and frame filter press for filtration, and the sucralose MVR mother liquor after filtration is a potassium-rich organic liquid.

[0037] Furthermore, the plate and frame filter press is arranged in a closed filter press room, a pipe collection is arranged on the top of the filter press room, the top of the filter press room is connected to a waste gas main pipe, the waste gas main pipe is connected to a secondary water washing tower, the secondary water washing tower is connected to an RTO furnace, and the RTO furnace is connected to an exhaust pipe.

[0038] Furthermore, the high-salt wastewater mother liquor resource recovery device includes an ammonia recovery tower tail gas treatment device, and the ammonia recovery tower tail gas treatment device includes:

[0039] A water absorption tower, a liquid phase pipeline and a gas phase pipeline are arranged between the water absorption tower and the ammonia recovery tower, the tail gas of the ammonia recovery tower enters the water absorption tower through the gas phase pipeline to be further absorbed, pure water as the first absorbent is added to the water absorption tower, and the saturated ammonia water flows back to the ammonia recovery tower through the liquid phase pipeline;

[0040] Dilute hydrochloric acid absorption tower, the water absorption tower is connected to the dilute hydrochloric acid absorption tower through a pipeline, the tail gas of the water absorption tower enters the dilute hydrochloric acid absorption tower for further absorption, and the second absorbent used is 5% dilute hydrochloric acid;

[0041] The tail gas from the dilute hydrochloric acid absorption tower is led to the main exhaust pipe of the workshop through a pipeline, first pre-treated by the workshop's secondary water washing tower, and then incinerated in the RTO furnace;

[0042] The dilute hydrochloric acid absorption tower is connected to the alkaline hydrolysis kettle through a pipeline, and the dilute hydrochloric acid absorption wastewater is used for the alkaline hydrolysis kettle to continue alkaline hydrolysis to recover dimethylamine and ammonia.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] 1) The present invention uses potassium hydroxide solution to perform alkaline hydrolysis on sucralose MVR mother liquor to generate dimethylamine and ammonia, removes ammonia / amine by evaporation, and completely evaporates the water of the sucralose MVR mother liquor in the alkaline hydrolysis kettle, and the condensate is supplemented to the ammonia recovery tower, and the non-condensable gas is sent to the ammonia recovery tower. The dimethylamine and ammonia in the non-condensable gas adsorb the condensate, and the adsorption saturated amine / ammonia water is sent to a dimethylamine distillation tower recovery device, and the dimethylamine and ammonia are separated by the dimethylamine distillation tower recovery device to obtain liquid dimethylamine and ammonia, thereby achieving the purpose of resource utilization of the sucralose MVR mother liquor, reducing the waste of resources in the sucralose MVR mother liquor, and reducing the cost of resource utilization of the sucralose MVR mother liquor.

[0045] 2) The present invention uses potassium hydroxide solution to perform alkaline hydrolysis on sucralose MVR mother liquor to produce dimethylamine / ammonia, and the dimethylamine / ammonia is recovered by an ammonia recovery device. The alkaline-hydrolyzed sucralose MVR mother liquor is then subjected to activated carbon adsorption and filter pressing to obtain a potassium-rich organic liquid, thereby achieving the purpose of resource utilization of the sucralose MVR mother liquor. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a structural block diagram of the high-salt wastewater mother liquor resource recovery device of the present invention;

[0047] Figure 2 The present invention is a flow chart of the process for resource recovery of high-salt wastewater mother liquor. DETAILED DESCRIPTION

[0048] The technical solution of the present invention will be clearly described below in conjunction with the accompanying drawings. Obviously, the described embodiments are not all embodiments of the present invention, and all other embodiments obtained by ordinary technicians in the field without making creative work are within the protection scope of the present invention.

[0049] It should be noted that the directions or positional relationships indicated by terms such as “center”, “up”, “down”, “horizontal”, “left”, “right”, “front”, “back”, “lateral” and “longitudinal” are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0050] Example 1

[0051] like Figure 1 As shown, the present invention provides a high-salinity wastewater mother liquor resource recovery device, comprising:

[0052] Alkaline hydrolysis kettle is used for the place where alkaline hydrolysis reaction occurs. The alkaline hydrolysis kettle is a jacketed reactor. The jacketed reactor adopts the existing technology. The jacketed reactor is composed of an inner shell, a jacket, an agitator, a transmission mechanism, a heating and cooling system, etc. Among them, the inner shell is a container for reactants, and the jacket is a medium channel for heating and cooling. The agitator can fully mix the reactants, the transmission mechanism provides power, and the heating and cooling system can control the reaction temperature. The working principle of the jacketed reactor is to control the temperature of the reaction system through the heat conduction medium flowing in the jacket. When the reaction system needs to be heated, the heating system supplies heat to the medium flowing in the jacket to increase the temperature of the reaction system; conversely, the cooling system supplies cold to the medium flowing in the jacket to reduce the temperature of the reaction system. The agitator can fully mix the reactants and increase the reaction rate.

[0053] The top of the alkaline hydrolysis kettle is connected to the high-level tank through a pipeline. During the alkaline hydrolysis reaction, after adding sucralose MVR mother liquor to the alkaline hydrolysis kettle, the stirrer stirs, and then 48% potassium hydroxide is added to the high-level tank. Steam is introduced into the jacket, and the jacket is heated to a preset temperature, which is 110°C-130°C in the present invention, and potassium hydroxide reacts with dimethylamine hydrochloride, ammonium chloride, etc. in the sucralose MVR mother liquor to undergo an alkaline hydrolysis reaction.

[0054] Condenser 1, a gas phase pipeline and a liquid phase pipeline are arranged between the top of the alkaline hydrolysis kettle and condenser 1. After the alkaline hydrolysis reaction, the gas phase in the alkaline hydrolysis kettle is sent to condenser 1 through the gas phase pipeline. The gas phase includes dimethylamine, ammonia and water vapor. Condenser 1 adopts a first-level normal temperature water cooling. After the gas phase is cooled in condenser 1, the condensate flows back to the alkaline hydrolysis kettle through the liquid phase pipeline. After the non-condensable gas goes to the rear ammonia recovery tower, it is absorbed by the ammonia recovery tower and then the dimethylamine and ammonia are recovered.

[0055] Ammonia recovery tower, condenser 1 is directly connected to the ammonia recovery tower through a pipeline, and the pipeline is used to transport non-condensable gas. The non-condensable gas enters the ammonia recovery tower after passing through the pipeline.

[0056] Gas-liquid separation tank: A special gas-liquid separation tank is connected to the bottom of the condenser. In the gas-liquid separation tank, the condensate and the uncondensed gas (non-condensable steam) are separated.

[0057] Condensate recovery tank, gas-liquid separation tank is connected to ammonia recovery tower through pipeline via condensate recovery tank, and this branch is used to supplement condensate to ammonia recovery tower. After the alkaline hydrolysis reaction is completed, the material in the alkaline hydrolysis kettle is evaporated to remove ammonia / amine. During the evaporation process, in the first stage, the gas phase is first condensed by condenser 1 and refluxed into the alkaline hydrolysis kettle; in the second stage, the direction of the condensate is switched, the gas phase is first condensed by condenser 1 and then enters the gas-liquid separation tank, the condensate in the gas-liquid separation tank is pumped to the condensate recovery tank, and then the condensate is supplemented to the ammonia recovery tower by the condensate recovery tank, so that the dimethylamine and ammonia in the non-condensable steam absorb liquid water. A switching valve is provided on the reflux pipeline between the alkaline hydrolysis kettle and the condenser 1, and a switching valve is also provided on the pipeline between the gas-liquid separation tank and the condensate recovery tank. By controlling the on and off of the switching valves on the two pipelines, the switching direction of the condensate is controlled (the switching valve is not shown in the figure).

[0058] The ammonia recovery tower is connected to a dimethylamine distillation tower recovery device at the rear end, which is used to separate the dimethylamine recovered by the ammonia recovery tower from ammonia to obtain liquid dimethylamine and 20% ammonia water byproduct. The dimethylamine distillation tower recovery device includes: the ammonia recovery tower is responsible for recovering a mixture containing dimethylamine and ammonia. The recovered adsorption saturated amine / ammonia water is sent to the intermediate storage tank.

[0059] The intermediate storage tank is connected to the ammonia recovery tower through a pipeline and is used to store the adsorption saturated amine / ammonia water recovered by the ammonia recovery tower. The materials in the intermediate storage tank are sent to the deammonification tower through a pipeline.

[0060] The deamination tower is connected to the intermediate storage tank. The deamination tower is used to remove ammonia / amines from water. The treated gas phase is sent to condenser three, and the liquid phase continues to flow to the dimethylamine distillation tower.

[0061] The dimethylamine distillation tower is connected to the deamination tower through a pipeline. The dimethylamine distillation tower is used to distill the dimethylamine treated by the deamination tower. The dimethylamine distillation tower wastewater generated by the distillation is discharged to the sewage station.

[0062] Condenser 2, the dimethylamine distillation tower is connected to condenser 2 through a pipeline, and the dimethylamine vapor after dimethylamine distillation tower distillation enters condenser 2 for condensation, and in condenser 2, the dimethylamine vapor is cooled and condensed into liquid. The uncondensed steam of the dimethylamine distillation tower is discharged to the incinerator.

[0063] The reflux tank is connected to the reflux tank by a pipeline. The dimethylamine condensate condensed by the condenser 2 flows back to the reflux tank. The reflux tank stores the dimethylamine condensate from the condenser 2, and finally obtains the refined main product, 99% pure liquid dimethylamine.

[0064] Condenser 3, the deamination tower is connected to condenser 3 through a pipeline. Condenser 3 cools the gas phase of the deamination tower. The gas phase after the deamination tower is sent to condenser 3, and the condensate cooled by condenser 3 flows back to the deamination tower. The non-condensable gas is sent to the ammonia absorption tower.

[0065] Ammonia absorption tower, condenser 3 is connected to the ammonia absorption tower through a pipeline, the non-condensable gas of condenser 3 is sent to the ammonia absorption tower, pure water is added to the ammonia absorption tower as an absorbent, and ammonia water with a purity of 20% is obtained as a by-product. The tail gas of the ammonia absorption tower is discharged to the incinerator.

[0066] The present invention realizes efficient recovery of dimethylamine and ammonia through an ammonia recovery tower and a dimethylamine rectification tower. High-purity liquid dimethylamine is obtained through rectification and reflux operations. Ammonia in non-condensable gas is converted into 20% pure ammonia water through an ammonia absorption tower, thereby realizing maximum utilization of resources. Wastewater is discharged to a sewage station for treatment, and tail gas from non-condensable gas and the ammonia absorption tower is discharged to an incinerator, thereby reducing environmental pollution.

[0067] The high-salt wastewater mother liquor resource recovery device also includes:

[0068] Plate and frame filter press, the bottom of the alkaline hydrolysis kettle is connected to the plate and frame filter press through a pipeline. The plate and frame filter press is set in a closed filter press room, and a pipeline collection is set on the top of the filter press room. The top of the filter press room is connected to the exhaust gas main pipe, the exhaust gas main pipe is connected to the secondary water washing tower, the secondary water washing tower is connected to the RTO furnace (storage thermal incinerator), and the RTO furnace is connected to the exhaust pipe 1, and the height of the exhaust pipe 1 is 25m.

[0069] Vacuum feeder: The bottom of the alkaline hydrolysis kettle is connected with a vacuum feeder, which has a built-in bag dust collector. The vacuum feeder is connected with exhaust pipe 2.

[0070] After the evaporation process is completed, pure water is added to the alkaline hydrolysis kettle for dilution, and then 35% hydrochloric acid is slowly added to the high-level tank to adjust the liquid in the alkaline hydrolysis kettle to neutral. A small amount of high-level tank waste gas is generated during the hydrochloric acid addition process. The volatilized waste gas in the neutralization process enters the condenser 1, and the condensate is pumped into the condensate recovery tank through the gas-liquid separation tank, and the non-condensable gas enters the ammonia recovery tower through hydraulic injection.

[0071] After the neutralization reaction is completed, activated carbon is added to the alkaline hydrolysis kettle through a vacuum feeder. During the process of adding activated carbon, a small amount of feed waste gas is discharged through the second exhaust pipe, and the height of the second exhaust pipe is 15m. Activated carbon can adsorb insoluble solids such as caramel and solid particles in the sucralose MVR mother liquor. After stirring for 15 minutes, the material in the alkaline hydrolysis kettle is transported to the plate and frame filter press through a pipeline for filtration. The sucralose MVR mother liquor is filtered to obtain a by-product potassium-rich organic liquid, which is pumped into a storage tank for storage and sale.

[0072] The filter press waste gas is led to the workshop waste gas main through a pipeline, first pre-treated by the workshop's secondary water washing tower, and then incinerated in the RTO furnace. The tail gas is discharged through the existing exhaust pipe.

[0073] The waste residue from filter press is mainly waste activated carbon, which is incinerated at the hazardous waste disposal center.

[0074] The waste gas of the present invention is processed in multiple stages to ensure that it meets the emission standards and reduces the impact on the environment. The potassium-rich organic liquid as a by-product has high economic value and realizes the recycling of resources.

[0075] The high-salt wastewater mother liquor resource recovery device includes an ammonia recovery tower tail gas treatment device, and the ammonia recovery tower tail gas treatment device includes:

[0076] The water absorption tower adopts a primary atmospheric pressure water absorption tower. A liquid phase pipeline and a gas phase pipeline are arranged between the water absorption tower and the ammonia recovery tower. The tail gas of the ammonia recovery tower enters the water absorption tower through the gas phase pipeline to be further absorbed. Pure water is added to the water absorption tower as an absorbent, and the saturated ammonia water flows back to the ammonia recovery tower through the liquid phase pipeline.

[0077] The dilute hydrochloric acid absorption tower is connected to the water absorption tower through a pipeline. The tail gas of the water absorption tower enters the dilute hydrochloric acid absorption tower for further absorption. The absorbent used is 5% dilute hydrochloric acid prepared by adding 35% hydrochloric acid to water.

[0078] The tail gas from the dilute hydrochloric acid absorption tower is led to the main exhaust pipe of the workshop through a pipeline, and is first pre-treated by the workshop's secondary water washing tower, and then incinerated by the RTO furnace. Finally, the tail gas is discharged through the existing exhaust pipe. After the treatment of the dilute hydrochloric acid absorption tower, the tail gas is first pre-treated by the workshop's secondary water washing tower to remove residual pollutants. The pre-treated exhaust gas is then incinerated by the RTO furnace to ensure that the organic matter in the tail gas is completely burned and reduce emission pollution.

[0079] The dilute hydrochloric acid absorption wastewater jacket is connected to the dilute hydrochloric acid absorption tower, which is used to receive the wastewater from the dilute hydrochloric acid absorption tower. The dilute hydrochloric acid absorption wastewater jacket is connected to the alkaline hydrolysis kettle through a pipeline. The main components of the dilute hydrochloric acid absorption wastewater are dimethylamine hydrochloride, ammonium chloride, and water, which are the main components of the sucralose MVR mother liquor. Therefore, the dilute hydrochloric acid absorption wastewater can be reused in the alkaline hydrolysis kettle to continue alkaline hydrolysis to recover dimethylamine and ammonia, thereby realizing resource reuse.

[0080] The ammonia recovery tower tail gas treatment device effectively removes pollutants in the tail gas of the dilute hydrochloric acid absorption tower through multi-stage absorption and incineration treatment, ensuring that the emission meets the standards. The reuse of dilute hydrochloric acid absorption wastewater not only reduces wastewater discharge, but also realizes the reuse of resources and improves economic and environmental benefits.

[0081] In summary, the high-salt wastewater mother liquor resource utilization device is an efficient and environmentally friendly system that maximizes the utilization of resources.

[0082] Example 2

[0083] like Figure 1 As shown, the present invention provides a process for resource recovery of high-salt wastewater mother liquor, using the high-salt wastewater mother liquor resource recovery device of Example 1, and the process method is to use the strong alkalinity of potassium hydroxide to decompose dimethylamine hydrochloride and DMF, DMF is dimethylformamide, and form corresponding dimethylamine, potassium chloride and potassium formate; ammonium chloride can be decomposed into ammonia and potassium chloride. The specific process method includes the following steps:

[0084] Step S1, alkaline hydrolysis: after adding sucralose MVR mother liquor into the alkaline hydrolysis kettle according to a preset ratio, liquid potassium hydroxide is added into the alkaline hydrolysis kettle, mixed evenly, heated, and alkaline hydrolysis reaction is carried out; during the alkaline hydrolysis reaction, the gas phase is condensed, and the condensed water is fully refluxed into the alkaline hydrolysis kettle, and the non-condensable gas goes to the rear end ammonia recovery tower to absorb and recover dimethylamine and ammonia.

[0085] Specific:

[0086] Go 20m 3Pump an appropriate amount of sucralose MVR mother liquor (MVR concentrated mother liquor, extraction mother liquor) into the alkaline hydrolysis kettle. The MVR mother liquor is a concentrated mother liquor treated by MVR (i.e. mechanical vapor recompression) technology. The MVR mother liquor is a slightly viscous flowable liquid state. Turn on the stirring function of the alkaline hydrolysis kettle, and then slowly add 48% potassium hydroxide to the high-level tank in the alkaline hydrolysis kettle. The potassium hydroxide is excessive. After 1 hour of dropwise addition;

[0087] Steam is passed through, and the jacket of the alkaline hydrolysis kettle is heated to 110°C-130°C and kept warm for 24 hours. During the insulation process, potassium hydroxide reacts with dimethylammonium hydrochloride, ammonium chloride and the like in the mother liquor of sucralose MVR. Continuous stirring is performed during the insulation process to facilitate more complete alkaline hydrolysis of potassium hydroxide, DMF, dimethylammonium hydrochloride and other substances. In addition, since sugar substances are easily carbonized due to local high temperatures, stirring can make the materials heated evenly.

[0088] The specific reaction equation is as follows:

[0089] Equation 1, KOH + C2H7N.HCI → C2H7N + KCI + H2O,

[0090] Equation 2, KOH + NH4HCI → NH3 + KCI + H2O,

[0091] Equation 3, KOH + DMF → C2H7N + CHO2K, DMF is dimethylformamide,

[0092] Equation 4, 2KOH + C2H7N.H2SO4 → C2H7N + K2SO4 + 2H2O,

[0093] Equation 5, KOH + C2H4O2 → C2H3O2K + H2O.

[0094] Step S2, after the alkaline hydrolysis reaction is completed, sampling and analysis are performed to detect the content of dimethylformamide and dimethylamine hydrochloride in the material remaining in the alkaline hydrolysis kettle after alkaline hydrolysis. When the mass concentrations of dimethylformamide and dimethylamine hydrochloride are both less than 0.1%, the next process is performed and step S3 is executed; otherwise, liquid potassium hydroxide is continued to be added to extend the alkaline hydrolysis reaction time of step S1 until it is qualified.

[0095] The gas phase after the alkaline hydrolysis reaction, including dimethylamine, ammonia and water vapor, is sent to the condenser, and the condensate is refluxed to the alkaline hydrolysis kettle, and the non-condensable gas is sent to the ammonia recovery tower to absorb and recover dimethylamine and ammonia.

[0096] Step S3, evaporation of ammonia / amine: after the alkaline hydrolysis is completed, the ammonia / amine is evaporated to completely evaporate the water in the alkaline hydrolysis kettle to completely recover the dimethylamine and ammonia produced in the alkaline hydrolysis kettle. The gas after the alkaline hydrolysis is sent to the condenser for condensation. The condensate is refluxed to the alkaline hydrolysis kettle in the first stage, and is sent to the condensate recovery tank in the second stage and then supplemented to the ammonia recovery tower. The non-condensable gas is sent to the ammonia recovery tower, and the ammonia recovery tower is used to absorb dimethylamine and ammonia.

[0097] Specifically, after the condensation, gas-liquid separation and alkaline hydrolysis reaction of step S2 are completed, the vacuum pump is turned on to control the temperature in the alkaline hydrolysis kettle to 90°C-110°C and the negative pressure to -10kPa--5kPa to evaporate and remove ammonia / amine;

[0098] During the evaporation process, the gas phase is condensed by condenser 1 and then refluxed into the alkaline hydrolysis kettle. After reflux for 12 hours, the condensate is switched to the condensate recovery tank and the evaporation is continued for 2 hours to completely evaporate the water so as to completely recover the dimethylamine and ammonia produced in the alkaline hydrolysis kettle. The gas phase is first condensed by condenser 1 and then enters the gas-liquid separation tank matched with condenser 1. The condensate of the gas-liquid separation tank is then pumped into the condensate recovery tank and then supplemented to the ammonia recovery tower.

[0099] Step S4, amine refining: the adsorbed saturated amine / ammonia water is sent to a dimethylamine distillation tower recovery device, and separated by the dimethylamine distillation tower recovery device to obtain liquid dimethylamine and 20% ammonia water by-product.

[0100] Step S5, dissolving: Since a large amount of water evaporates in the alkaline hydrolysis kettle during the evaporation deamination / deamination process, the material at the bottom of the alkaline hydrolysis kettle is viscous and difficult to flow, and is difficult to stir, which is not conducive to the subsequent process. Therefore, pure water is pumped into the sucralose MVR mother liquor in the alkaline hydrolysis kettle after evaporation deamination / deamination, and the material is stirred to dissolve and dilute.

[0101] A small amount of waste gas volatilized during the dissolution process enters condenser 1, the condensate is pumped into the condensate recovery tank through the gas-liquid separation tank, and the non-condensable gas enters the ammonia recovery tower through hydraulic injection.

[0102] Step S6, neutralization: The dissolved sucralose MVR mother liquor is alkaline and has a low water content. Water is added to dilute and dissolve it, and then 35% hydrochloric acid is added to adjust the pH to neutral.

[0103] Specific:

[0104] Slowly drop 35% hydrochloric acid into the high-level tank in the alkaline hydrolysis kettle for neutralization. Use the submerged drop method to reduce the generation of waste gas. The drop addition is completed in 15 minutes. The liquid in the alkaline hydrolysis kettle is adjusted to neutral. A small amount of waste gas from the high-level tank is generated during the drop addition of hydrochloric acid to the high-level tank. The volatilized waste gas during the neutralization process enters the condenser 1, and the condensate is pumped into the condensate recovery tank through the gas-liquid separation tank. The non-condensable gas enters the ammonia recovery tower through hydraulic injection. The following reactions occur during the neutralization process:

[0105] KOH+HCl→KCI+H2O.

[0106] Step S7, filter pressing: After neutralization, add powdered activated carbon to the alkaline hydrolysis kettle, and filter press to separate caramel, solid particles and insoluble solids in the sucralose MVR mother liquor. The filter press waste gas generated by the filter press is washed and incinerated before being discharged, and the filter press waste residue generated by the filter press is incinerated and discharged, and the filtrate generated by the filter press is the by-product potassium-rich organic liquid.

[0107] Specifically, activated carbon is added into the alkaline hydrolysis kettle in vacuum, and the activated carbon can adsorb insoluble solids such as caramel and solid particles in the sucralose MVR mother liquor. After stirring with the agitator for 15 minutes, the materials in the alkaline hydrolysis kettle are transported to the plate and frame filter press through a pipeline for filtration. The plate and frame filter press is arranged in a closed filter press room.

[0108] A collection pipe is set on the top of the filter press room. The filter press waste gas is led to the workshop waste gas main pipe through the pipe. It is first pre-treated in the workshop's secondary water washing tower and then incinerated in the RTO furnace. The exhaust gas is discharged through an existing 25m high exhaust pipe.

[0109] The waste residue from filter press is mainly waste activated carbon, which is incinerated at the hazardous waste disposal center.

[0110] Activated carbon is in powder form. In order to reduce the generation of dust during feeding, a vacuum feeder is used for feeding. The feeder has a built-in bag dust collector. After treatment, a small amount of feed waste gas is discharged through a 15m high exhaust pipe.

[0111] The filtered sucralose MVR mother liquor is the by-product potassium-rich organic liquid, which is pumped into a storage tank for storage and sale.

[0112] Step S8, ammonia recovery tower waste gas treatment:

[0113] The pressure of the gas-liquid separation tank is controlled at -70 to -30 kPa, and ammonia is extracted under negative pressure. The gas phase (mainly dimethylamine, water vapor and ammonia) enters the ammonia recovery tower through hydraulic jet absorption. The absorbent used is pure water and the condensate in the condensate recovery tank. The ammonia recovery tower is a pressure equipment, and the drain port is not often opened. The pressure relief will be opened only when the pressure is too high.

[0114] The tail gas from the ammonia recovery tower enters the primary normal pressure water absorption tower for further absorption. The absorbent used is pure water. The absorption liquid after absorbing the tail gas flows back to the ammonia recovery tower for absorption. The tail gas from the water absorption tower enters the dilute hydrochloric acid absorption tower for further absorption. The absorbent used is 5% dilute hydrochloric acid prepared by adding 35% hydrochloric acid to water. The tail gas from the dilute hydrochloric acid absorption tower is led to the workshop exhaust gas main pipe through a pipeline, first pre-treated by the workshop secondary water washing tower, and then incinerated by the RTO furnace. Finally, the tail gas is discharged through an existing exhaust pipe.

[0115] The main components of the dilute hydrochloric acid absorption wastewater produced by the dilute hydrochloric acid absorption tower are dimethylammonium hydrochloride, ammonium chloride, and water, which are the main components in the sucralose MVR mother liquor. Therefore, it can be reused in the alkaline hydrolysis kettle to continue alkaline hydrolysis to recover dimethylamine and ammonia.

[0116] The above technical features constitute the best embodiment of the present invention, which has strong adaptability and best implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the needs of different situations.

[0117] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. A process for resource utilization of high-salt wastewater mother liquor, characterized in that: The steps include: Step S1, alkaline hydrolysis: after adding sucralose MVR mother liquor into the alkaline hydrolysis kettle according to a preset ratio, liquid potassium hydroxide is added into the alkaline hydrolysis kettle, mixed evenly, heated, and alkaline hydrolysis reaction is carried out; during the alkaline hydrolysis reaction, the gas phase is condensed, and the condensed water is fully refluxed into the alkaline hydrolysis kettle, and the non-condensable gas enters the ammonia recovery tower for absorption and then recovers the dimethylamine and ammonia in the gas; Step S2, sampling and analysis after the alkaline hydrolysis reaction is completed, detecting the content of dimethylformamide and dimethylamine hydrochloride in the material remaining in the alkaline hydrolysis kettle after alkaline hydrolysis, and executing step S3 after the mass concentrations of dimethylformamide and dimethylamine hydrochloride are both less than the set content; otherwise, continue to add liquid potassium hydroxide, and extend the alkaline hydrolysis reaction time of step S1 until the mass concentrations of dimethylformamide and dimethylamine hydrochloride are both less than the set content; Step S3, evaporation and deamination / amine: after the alkaline hydrolysis is completed, the deamination / amine is evaporated, the water of the sucralose MVR mother liquor in the alkaline hydrolysis kettle is evaporated completely, the gas after the alkaline hydrolysis is sent to the condenser for condensation, the condensate is refluxed to the alkaline hydrolysis kettle within a preset first time period, and is replenished to the ammonia recovery tower within a preset second time period, the non-condensable gas is sent to the ammonia recovery tower, and the dimethylamine in the non-condensable gas and the ammonia absorb the condensate; Step S4, amine refining: the adsorbed saturated ammonia / amine water is sent to a dimethylamine distillation tower recovery device, and liquid dimethylamine and ammonia water are separated by the dimethylamine distillation tower recovery device.

2. The process according to claim 1, characterized in that: Also includes: Step S5, dissolving: adding pure water to the sucralose MVR mother liquor after evaporation and deamination, stirring to dissolve and dilute the material; The volatilized waste gas during the dissolution process is sent to the condenser 1 through the pipeline, the condensate is pumped into the condensate recovery tank through the gas-liquid separation tank, and the non-condensable gas enters the ammonia recovery tower through hydraulic injection; Step S6, neutralization: the dissolved sucralose MVR mother liquor is alkaline, water is added to the alkaline hydrolysis kettle to dilute and dissolve, and then 35% hydrochloric acid is added to adjust the pH to neutral; Step S7, filter pressing: After neutralization, powdered activated carbon is added to the alkaline hydrolysis kettle, and the insoluble solids in the sucralose MVR mother liquor are separated by filter pressing, and the potassium-rich organic liquid is obtained by dissolving, neutralizing and filter pressing.

3. The process according to claim 2, characterized in that: Also includes: Step S8, ammonia recovery tower waste gas treatment: The tail gas from the ammonia recovery tower is sent to the water absorption tower for absorption by the first absorbent, the first absorbent is pure water, and the absorption liquid after absorbing the tail gas from the ammonia recovery tower flows back to the ammonia recovery tower to participate in absorption; The tail gas from the water absorption tower enters the dilute hydrochloric acid absorption tower and is further absorbed by the second absorbent, which is 5% dilute hydrochloric acid; The tail gas from the dilute hydrochloric acid absorption tower is pre-treated by water washing and then incinerated in the RTO furnace before being discharged; The waste water from the dilute hydrochloric acid absorption tower is returned to the alkaline hydrolysis kettle to continue alkaline hydrolysis to recover gaseous dimethylamine and ammonia.

4. A high-salinity wastewater mother liquor resource recovery device, characterized in that: include: The alkaline hydrolysis kettle is a jacketed reactor. The top of the alkaline hydrolysis kettle is connected with an elevated tank through a pipeline. A gas phase pipeline and a liquid phase pipeline are arranged between the top of the alkaline hydrolysis kettle and a condenser. The condenser is directly connected with an ammonia recovery tower through the gas phase pipeline. The rear end of the ammonia recovery tower is connected with a dimethylamine distillation tower recovery device. After the gas phase in the alkaline hydrolysis kettle is cooled in the condenser, the condensate flows back to the alkaline hydrolysis kettle through the liquid phase pipeline, and the non-condensable gas goes to the rear end ammonia recovery tower. The ammonia recovery tower absorbs and recovers dimethylamine and ammonia. The dimethylamine distillation tower recovery device separates the dimethylamine recovered by the ammonia recovery tower from ammonia, and finally obtains liquid dimethylamine and ammonia water.

5. The high-salt wastewater mother liquor resource recovery device according to claim 4, characterized in that: A matching gas-liquid separation tank is connected to the bottom of condenser one, and the gas-liquid separation tank is connected to the ammonia recovery tower through a liquid phase pipeline. A condensed water recovery tank is arranged between the gas-liquid separation tank and the ammonia recovery tower. The gas phase in the alkaline hydrolysis kettle is first condensed by condenser one and refluxed into the alkaline hydrolysis kettle, and then enters the gas-liquid separation tank after condensation by condenser one. The liquid in the gas-liquid separation tank is sent to the condensed water recovery tank, and then the condensed liquid is replenished to the ammonia recovery tower by the condensed water recovery tank.

6. The high-salt wastewater mother liquor resource recovery device according to claim 5, characterized in that: The dimethylamine distillation tower recovery device includes: An intermediate storage tank, which is connected to the ammonia recovery tower through a pipeline and is used to store adsorption-saturated amine / ammonia recovered by the ammonia recovery tower; A deamination tower, the intermediate storage tank is connected to a deamination tower, and the deamination tower is used to remove amines / ammonia in water; A dimethylamine distillation tower, wherein the deamination tower is connected to the dimethylamine distillation tower through a pipeline to distill dimethylamine; Condenser 2, the dimethylamine distillation tower is connected to condenser 2 through a pipeline, and the dimethylamine after distillation is separated into gas and liquid through condenser 2; The reflux tank is connected to the condenser 2 through a pipeline, and the condensed liquid dimethylamine is refluxed to the reflux tank to finally obtain the refined liquid dimethylamine.

7. The high-salt wastewater mother liquor resource recovery device according to claim 6, characterized in that: The dimethylamine distillation tower recovery device includes: Condenser 3, the deamination tower is connected to condenser 3 through a pipeline, the gas phase after the deamination tower is sent to condenser 3, and the condensate after cooling by condenser 3 flows back to the deamination tower; Ammonia absorption tower: Condenser three is connected to the ammonia absorption tower through a pipeline, and the non-condensable gas of condenser three is sent to the ammonia absorption tower. Pure water is added to the ammonia absorption tower to obtain ammonia water.

8. The high-salinity wastewater mother liquor resource recovery device according to claim 4, characterized in that: The high-salt wastewater mother liquor resource recovery device includes: Vacuum loader: a vacuum loader is connected to the bottom of the alkaline hydrolysis kettle, and the vacuum loader has a built-in bag dust collector; Plate and frame filter press: the bottom of the alkaline hydrolysis kettle is connected with a plate and frame filter press through a pipeline; Activated carbon is added to the plate and frame filter press through a vacuum feeder. After the activated carbon adsorbs the insoluble solids in the sucralose MVR mother liquor, the materials in the alkaline hydrolysis reactor are transported to the plate and frame filter press for filtration. The sucralose MVR mother liquor after filtration is a potassium-rich organic liquid.

9. The high-salinity wastewater mother liquor resource recovery device according to claim 8, characterized in that: The plate and frame filter press is arranged in a closed filter press room. A pipe collection is arranged on the top of the filter press room. The top of the filter press room is connected to an exhaust gas main pipe, the exhaust gas main pipe is connected to a secondary water washing tower, and the secondary water washing tower is connected to an RTO furnace.

10. The high-salinity wastewater mother liquor resource recovery device according to claim 4, characterized in that: The high-salt wastewater mother liquor resource recovery device includes an ammonia recovery tower tail gas treatment device, and the ammonia recovery tower tail gas treatment device includes: A water absorption tower, a liquid phase pipeline and a gas phase pipeline are arranged between the water absorption tower and the ammonia recovery tower, the tail gas of the ammonia recovery tower enters the water absorption tower through the gas phase pipeline to be further absorbed, pure water as the first absorbent is added to the water absorption tower, and the saturated ammonia water flows back to the ammonia recovery tower through the liquid phase pipeline; Dilute hydrochloric acid absorption tower, the water absorption tower is connected to the dilute hydrochloric acid absorption tower through a pipeline, the tail gas of the water absorption tower enters the dilute hydrochloric acid absorption tower for further absorption, and the second absorbent used is 5% dilute hydrochloric acid; The tail gas from the dilute hydrochloric acid absorption tower is led to the main exhaust pipe of the workshop through a pipeline, first pre-treated by the workshop's secondary water washing tower, and then incinerated in the RTO furnace; The dilute hydrochloric acid absorption tower is connected to the alkaline hydrolysis kettle through a pipeline, and the dilute hydrochloric acid absorption wastewater is used for the alkaline hydrolysis kettle to continue alkaline hydrolysis to recover dimethylamine and ammonia.

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