Glycerin residue recycling process and glycerin residue recycling treatment system

Abstract

The application discloses a glycerol residue recycling process and a glycerol residue recycling treatment system, and the glycerol residue is diluted, impurities are removed through filtration, calcium oxide and sodium metaaluminate are added for reaction to generate and recycle a Fred salt, the filtrate is adjusted in pH, sodium carbonate is added to generate and recycle calcium carbonate, then the filtrate is subjected to microfiltration to remove glue, ultrafiltration to separate high-polymerization polyglycerol for recycling and nanofiltration to separate low-polymerization polyglycerol for recycling, and finally glycerol solution is recycled, the chlorides, glycerol, low-polymerization polyglycerol and high-polymerization polyglycerol in the glycerol residue are finely separated, inorganic salts are made into heavy metal capturing agents and refined calcium carbonate, glycerol is made into a water treatment carbon source, low-polymerization polyglycerol is made into refined polyglycerol, and high-polymerization polyglycerol is made into a liquid cement grinding aid, fine recycling of resources is realized, and no flammable and explosive solvent is used in the treatment process, so that the safety is high.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of resource recycling, in particular to a glycerol residue recycling process and a glycerol residue recycling treatment system. BACKGROUND

[0002] The most commonly used refining technology for crude glycerol is rectification separation technology. Regardless of the rectification technology, glycerol residue will be produced after rectification. The main components of glycerol residue are inorganic salts, glycerol (glycerol and polyglycerol) and impurities. The treatment of glycerol residue is difficult. The treatment by landfill and combustion not only pollutes the environment but also wastes resources. A feasible recycling process is needed to recover the available resources in glycerol residue and realize the resource utilization of waste.

[0003] When glycerol is rectified by sulfuric acid conditioning, in order to avoid the generation of sulfide gas, the rectification will not be excessive. The rectification mother liquor produced contains a high amount of water. The solid residue (glycerol residue) separated by centrifugation of the rectification mother liquor contains more than 70% inorganic salts. The resource utilization of glycerol residue is mainly the recovery of waste salt. In Chinese patent CN 114773159 B, the glycerol residue mainly containing sulfate is recycled by crystallization. The glycerol residue is diluted with water and then crystallized at low temperature to separate the salt. The solid phase of the crystallized salt is sodium sulfate. This process only recovers the glycerol residue containing sulfate and does not achieve fine utilization of glycerol.

[0004] When glycerol is rectified by hydrochloric acid conditioning, in order to improve the recovery rate of glycerol, the glycerol is often "baked" at high temperature. The inorganic salt crystallizes and separates out as the water content decreases. The separated inorganic salt is washed and reused. The liquid phase of the rectification mother liquor contains a low amount of water. The mother liquor is cooled and condensed into solid or semi-solid residue. The glycerol residue contains less than 50% inorganic salt and more than 35% glycerol (glycerol and polyglycerol). The resource utilization of glycerol residue is mainly the recovery of glycerol. For the recycling of glycerol residue containing chloride, organic solvents such as ethanol and isopropyl alcohol can be used to extract and recover glycerol. However, these solvents are flammable and explosive, which is not safe. Molecular distillation can also be used to evaporate and recover glycerol. However, this process can only separate and recover glycerol from glycerol, and the polyglycerol and chloride are co-crystallized and discarded, which does not achieve fine resource utilization. The solubility of conventional inorganic chloride in water is relatively high, which makes it difficult to separate and recover chloride by crystallization. Ion exchange resin can also be used to adsorb and recover salt to recover glycerol. However, this process cannot recover inorganic salt, which does not achieve fine resource utilization.

[0005] Currently, the existing glycerol residue recycling processes have the following problems:

[0006] 1) The safety of organic solvents is poor;

[0007] 2) Inorganic salt, glycerol and polyglycerol are not completely separated, and fine resource utilization is not achieved;

[0008] 3) Chloride ions are difficult to separate, and there is no specific method for glycerol residue in chloro salt system. SUMMARY

[0009] In order to overcome the above-mentioned defects, the present application provides a glycerol residue recycling process and a glycerol residue recycling treatment system, which realizes fine recycling of glycerol residue resources, and has high safety in the whole process.

[0010] The technical scheme adopted by the present application to solve the technical problems is: a glycerol residue recycling process, comprising the following steps:

[0011] Step one: dilution of glycerol residue:

[0012] The glycerol residue with inorganic salt components mainly in the form of chloro salt is diluted with water;

[0013] Step two: filtration and impurity removal:

[0014] The glycerol residue diluent is filtered to remove colloidal impurities in the glycerol residue diluent;

[0015] Step three: removal of chloride by Frey salt method:

[0016] The filtered glycerol residue diluent is pumped into a reaction kettle, and calcium oxide and sodium metaaluminate are added to the reaction kettle to generate Frey salt, and the Frey salt precipitate and supernatant generated by the reaction are separated, the Frey salt precipitate is recycled, and the supernatant flows out, wherein the addition amount of calcium oxide and sodium metaaluminate is added according to n(Ca)∶n(Al)∶n(Cl)=5-20∶2-5∶1;

[0017] Step four: conditioning of the filtrate:

[0018] The supernatant after separation of the Frey salt precipitate in step three is detected for chloride ion content;

[0019] If the chloride ion content is >500mg / L, repeat step three;

[0020] If the chloride ion content is ≤500mg / L, add sulfuric acid to adjust the pH of the supernatant to neutral, and at the same time, add sodium carbonate to react with calcium ions in the supernatant after separation of the Frey salt precipitate to form calcium carbonate, the addition amount of sodium carbonate is determined by the standard that no more precipitate is produced after continuously adding sodium carbonate to the supernatant after separation of the Frey salt precipitate, and the calcium carbonate precipitate is separated and recycled;

[0021] Step five: microfiltration to remove gel:

[0022] The supernatant produced in step four is filtered using a microfiltration membrane, and macromolecular organic matter with a molecular weight greater than 1 million and residual colloids are separated into a microfiltration concentrate, and a microfiltration clear liquid is obtained;

[0023] Step six: ultrafiltration separation

[0024] The microfiltration clear liquid is filtered by an ultrafiltration membrane, high polymerization degree polyglycerol with a molecular weight of 1000 or above is separated into an ultrafiltration concentrate and recovered as a liquid cement grinding aid raw material, and an ultrafiltration clear liquid is obtained;

[0025] Step seven: nanofiltration separation

[0026] The ultrafiltration clear liquid is filtered by a nanofiltration membrane, low polymerization degree polyglycerol with a molecular weight of 200-1000 and sulfate are separated into a nanofiltration concentrate and recovered, a nanofiltration clear liquid with glycerol as a main component is obtained, and the nanofiltration clear liquid is used as a glycerol solution.

[0027] As a further improvement of the present application, in the step one, when the glycerol residue with chlorides as the main inorganic salt component is diluted with water, the specific gravity is controlled to be between 1 and 1.05, and the salinity is controlled to be between 5000 and 50000 mg / L.

[0028] As a further improvement of the present application, in the step two, a filter press is used to filter the glycerol dilution liquid in the step one to remove colloidal impurities.

[0029] As a further improvement of the present application, in the step three, after the glycerol residue dilution liquid is added into the reaction kettle, the stirrer of the reaction kettle is started, the rotation speed of the stirrer is controlled to be between 80 and 500 r / min, the temperature of the glycerol residue dilution liquid in the reaction kettle is controlled to be between 10 and 30℃, and then calcium oxide and sodium metaaluminate are added for reaction.

[0030] As a further improvement of the present application, the Fehling salt precipitate obtained in the step three is separated by a filter press and recovered as a heavy metal capturing agent raw material.

[0031] As a further improvement of the present application, the calcium carbonate precipitate separated in the step four is washed and purified to prepare refined calcium carbonate for industrial production.

[0032] As a further improvement of the present application, the inorganic salt in the nanofiltration concentrate obtained in the step seven is adsorbed by an ion resin to prepare refined polyglycerol for industrial production.

[0033] A glycerol residue recycling system includes a glycerol residue dilution tank, a primary filter press, a secondary filter press, a tertiary filter press, a reaction vessel, a filtrate conditioning tank, a chloride ion concentration detector, a microfiltration membrane device, a microfiltration permeate tank, an ultrafiltration membrane device, an ultrafiltration permeate tank, and a nanofiltration membrane device. The glycerol residue dilution tank is connected to the inlet of the primary filter press via a pipeline. The diluted glycerol residue in the dilution tank can be pumped into the filter press via a booster pump. The filter press can filter the diluted glycerol residue to remove colloidal impurities. The filter outlet of the filter press is connected to the inlet of the reaction vessel via a pipeline, thereby supplying filtrate into the reaction vessel. The reaction vessel is also equipped with... The reactor features an openable and closable reagent inlet, supernatant outlet, and sediment outlet. The reagent inlet is used for adding reagents. The supernatant outlet discharges the supernatant formed after sedimentation following the reaction in the reactor. The sediment outlet discharges the sediment from the bottom of the reactor. The sediment outlet is connected to the inlet of a secondary filter press via a pipeline. The secondary filter press dehydrates the water-containing sediment discharged from the reactor to obtain solid fructose. The supernatant outlet is connected to the inlet of a filtrate conditioning tank via a pipeline. A chloride ion concentration detector is used to detect the chloride ion concentration in the liquid within the filtrate conditioning tank. The filtrate conditioning tank is also connected to the inlet of the reaction vessel via a pipeline. Liquid in the conditioning tank with excessive chloride ion concentration can be returned to the reaction vessel via a booster pump. The conditioning tank is equipped with a dosing port, a conditioning clarified liquid outlet, and a sedimentation separation port. The dosing port is used to add chemicals. The sedimentation separation port of the conditioning tank is connected to the inlet of a three-stage filter press via a pipeline. The three-stage filter press can dehydrate the water-containing sediment discharged from the conditioning tank to obtain solid calcium carbonate. The conditioning clarified liquid outlet of the conditioning tank is connected to the inlet of a microfiltration membrane device via a pipeline. The microfiltration membrane in the microfiltration membrane device can filter the filtrate... The conditioning solution discharged from the conditioning tank undergoes microfiltration treatment. The microfiltration solution from the microfiltration membrane device is discharged into the microfiltration product tank through a pipeline. The microfiltration product tank is connected to the inlet of the ultrafiltration membrane device through a pipeline. The microfiltration solution in the microfiltration product tank can be pumped into the ultrafiltration membrane device through a booster pump. The ultrafiltration membrane of the ultrafiltration membrane device can perform ultrafiltration treatment on the microfiltration solution. The ultrafiltration solution from the ultrafiltration membrane device is discharged into the ultrafiltration product tank through a pipeline. The ultrafiltration product tank is connected to the inlet of the nanofiltration membrane device through a pipeline. The ultrafiltration solution in the ultrafiltration product tank can be pumped into the nanofiltration membrane device through a booster pump. The nanofiltration membrane of the nanofiltration membrane device can perform nanofiltration treatment on the ultrafiltration solution.

[0034] As a further improvement of the present application, there are also provided a Fred salt deep processing device, a calcium carbonate washing and purifying device, a high polymerization degree polyglycerol deep processing device, a low polymerization degree polyglycerol deep processing device and a glycerol solution deep processing device, the Fred salt deep processing device is provided with a feeding port for feeding solid Fred salt and an auxiliary agent feeding port for feeding auxiliary agent, the Fred salt deep processing device can make the solid Fred salt produced by the secondary pressure filter into solid heavy metal capturing agent by adding auxiliary agent, the calcium carbonate washing and purifying device can wash and remove impurities from the solid substance containing calcium carbonate produced by the third pressure filter to obtain high-purity solid refined calcium carbonate product, the ultrafiltration concentrated liquid outlet of the ultrafiltration membrane device is communicated with the high polymerization degree polyglycerol deep processing device feeding port through a pipeline, the ultrafiltration concentrated liquid can be discharged into the high polymerization degree polyglycerol deep processing device, the high polymerization degree polyglycerol deep processing device can make the high polymerization degree polyglycerol in the ultrafiltration concentrated liquid into liquid cement grinding aid by adding auxiliary agent, the nanofiltration concentrated liquid outlet and the nanofiltration filtrate outlet of the nanofiltration membrane device are respectively communicated with the low polymerization degree polyglycerol deep processing device and the glycerol solution deep processing device through pipelines, the nanofiltration concentrated liquid and the nanofiltration filtrate can be respectively discharged into the low polymerization degree polyglycerol deep processing device and the glycerol solution deep processing device, the ion resin is arranged in the low polymerization degree polyglycerol deep processing device, the ion resin can remove the inorganic salt in the nanofiltration concentrated liquid, and finally obtain liquid refined polyglycerol, and the glycerol solution deep processing device can make the nanofiltration filtrate into liquid water treatment carbon source by adding auxiliary agent.

[0035] As a further improvement of the present application, the glycerol residue dilution tank, the reaction kettle and the filtrate conditioning tank are all provided with a stirrer for stirring the mixture.

[0036] The present application has the advantages that: the present application processes the glycerol residue in the chloro salt system, and no flammable and explosive solvent is used in the processing process, so the safety is high, the present application finely separates the chloro salt, glycerol, low polymerization degree polyglycerol, high polymerization degree polyglycerol in the glycerol residue, makes the inorganic salt into heavy metal capturing agent and refined calcium carbonate, makes the glycerol into water treatment carbon source, makes the low polymerization degree polyglycerol into refined polyglycerol, and makes the high polymerization degree polyglycerol into liquid cement grinding aid, so the fine recycling and utilization of resources are realized. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 The glycerol residue recycling process flowchart of the present application is shown in the figure;

[0038] Figure 2 The principle diagram of the glycerol residue recycling treatment system of the present application is shown in the figure. DETAILED DESCRIPTION

[0039] In order to make the advantages of the present application, the technical solutions used and the innovative points clearer, the present application will be described in further detail below in combination with the above drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0040] Embodiment: a glycerin residue recycling process,

[0041] comprising the following steps:

[0042] Step one: glycerin residue dilution:

[0043] The inorganic salt component is mainly chlorinated salt, and the glycerin residue is diluted with water;

[0044] Step two: impurity removal by filtration:

[0045] The glycerin residue dilution liquid is filtered to remove colloidal impurities in the glycerin residue dilution liquid;

[0046] Step three: removal of chlorine by Frey salt method:

[0047] The filtered glycerin residue dilution liquid is pumped into a reaction kettle 5, and calcium oxide and sodium metaaluminate are added to the reaction kettle 5 to generate Frey salt (Ca4Al2Cl2(OH)12) through reaction, and the Frey salt precipitate and supernatant generated by the reaction are separated, the Frey salt precipitate is recycled, and the supernatant flows out, wherein the addition amount of calcium oxide and sodium metaaluminate is added according to n(Ca)∶n(Al)∶n(Cl)=5-20∶2-5∶1;

[0048] Reaction mechanism of Frey salt method

[0049] (1) 2NaAlO2+4H2O→2Al(OH)3+2NaOH;

[0050] (2) 4Ca(OH)2+2Al(OH)3→Ca4Al2(OH)14;

[0051] (3) Ca4Al2(OH)14+2Cl - →Ca4Al2Cl2(OH)12+2OH - ;

[0052] (4) CaCl2+3Ca(OH)2+2NaAlO2+8H2O→

[0053] 2Ca2Al(OH)6Cl·4H2O+2NaOH;

[0054] Step four: filtrate conditioning:

[0055] The supernatant after separating the Friedel salt precipitate in step three is detected for chloride ion content;

[0056] If the chloride ion content is greater than 500 mg / L, repeat step three;

[0057] If the chloride ion content is less than or equal to 500 mg / L, add sulfuric acid to adjust the pH of the supernatant to neutral, and add sodium carbonate to react with calcium ions in the supernatant after separating the Friedel salt precipitate to form calcium carbonate. The amount of sodium carbonate added is determined by the criterion that no precipitate is produced when the supernatant after separating the Friedel salt precipitate is continuously added with sodium carbonate. The calcium carbonate precipitate is separated and recycled.

[0058] Step five: microfiltration to remove gelatin:

[0059] The supernatant produced in step four is filtered using a microfiltration membrane to separate macromolecular organic matter with a molecular weight greater than 1 million and residual gelatin into a microfiltration concentrate, and obtain a microfiltration clear liquid.

[0060] Step six: ultrafiltration separation:

[0061] The microfiltration clear liquid is filtered using an ultrafiltration membrane to separate high-polymerization-degree polyglycerol with a molecular weight of 1000 or more into an ultrafiltration concentrate as a liquid cement grinding aid raw material for recycling, and obtain an ultrafiltration clear liquid. The high-polymerization-degree polyglycerol with a molecular weight of 1000 or more mainly includes polyglycerol with a polymerization degree of 10 or more, which contains polar hydroxyl groups necessary for traditional cement grinding aids. These polar groups can combine with cement particles to prevent them from re-agglomerating during grinding. By adding certain additives, a liquid cement grinding aid can be prepared for cement production.

[0062] Step seven: nanofiltration separation:

[0063] The ultrafiltration clear liquid is filtered using a nanofiltration membrane to separate low-polymerization-degree polyglycerol with a molecular weight of 200-1000 and sulfate together into a nanofiltration concentrate for recycling, and obtain a nanofiltration clear liquid mainly composed of glycerol, which is used as a glycerol solution.

[0064] The glycerol solution can be used as a carbon source for denitrification and nitrogen removal in sewage treatment plants, has good biodegradability, is safe and reliable, and can be further prepared into various water treatment carbon sources by adding additives.

[0065] In step one, the glycerol residue with chloride salt as the main inorganic salt component is diluted with water, and the specific gravity is controlled to be between 1 and 1.05, and the salinity is controlled to be between 5000 and 50000 mg / L.

[0066] In step two, a filter press is used to filter the glycerol dilution liquid in step one to remove colloidal impurities.

[0067] After the glycerin residue dilution is added into the reactor 5 in the third step, the stirrer of the reactor 5 is started, the rotating speed of the stirrer is 80-500 r / min, and the temperature of the glycerin residue dilution in the reactor 5 is controlled at 10-30℃, then the calcium oxide and sodium metaaluminate are added for reaction. The glycerin residue dilution, calcium oxide and sodium metaaluminate are stirred and reacted in the reactor 5, and the reaction is sufficient.

[0068] The obtained Fries salt precipitate in the third step is separated by pressure filtration and recycled as raw material of heavy metal capturing agent. The Fries salt can effectively remove harmful anions (such as arsenate, chromate, selenate, antimonate, etc.) and inorganic heavy metal cations (cadmium ion, copper ion, lead ion, nickel ion, etc.) in wastewater, and by adding certain additives, a heavy metal capturing agent can be prepared for removing heavy metals in electroplating wastewater.

[0069] The separated calcium carbonate precipitate in the fourth step is washed and purified to prepare refined calcium carbonate for industrial production.

[0070] The inorganic salts in the nanofiltration concentrated water obtained in the seventh step are adsorbed by ion resin to prepare refined polyglycerol for industrial production. The low degree of polymerization polyglycerol with a molecular weight of 200-1000 obtained in the seventh step is mainly 2-9 polyglycerol, which has applications in cosmetics, fiber industry and plastic industry. By adsorbing the inorganic salts in the nanofiltration concentrated water by ion resin, refined polyglycerol can be prepared for industrial production.

[0071] The application discloses a glycerin residue recycling treatment system, which comprises a glycerin residue dilution tank 1, a first-stage filter press 2, a second-stage filter press 3, a third-stage filter press 4, a reaction kettle 5, a filtrate conditioning tank 6, a chloride ion concentration detector, a microfiltration membrane device 8, a microfiltration water bucket 9, an ultrafiltration membrane device 10, an ultrafiltration water bucket 11 and a nanofiltration membrane device 12; the glycerin residue dilution tank 1 is communicated with the inlet of the first-stage filter press 2 through a pipeline; the glycerin residue dilution liquid in the glycerin residue dilution tank 1 can be sent into the filter press through a lifting pump; the filter press can remove colloidal impurities by filtering the glycerin dilution liquid; the water outlet of the filter press is communicated with the liquid inlet of the reaction kettle 5 through a pipeline, thereby conveying the filtrate into the reaction kettle 5; the reaction kettle 5 is further provided with an openable and closable medicament adding port, a supernatant outlet and a sediment outlet; the medicament adding port is used for adding medicament; the supernatant outlet is used for discharging supernatant formed by reaction and sedimentation in the reaction kettle 5; the sediment outlet is used for discharging sediment at the bottom of the reaction kettle 5; the sediment outlet of the reaction kettle 5 is communicated with the inlet of the second-stage filter press 3 through a pipeline; the second-stage filter press 3 can filter and dewater the water-containing sediment discharged from the reaction kettle 5, thereby obtaining solid Fred salt; the supernatant outlet of the reaction kettle 5 is communicated with the water inlet of the filtrate conditioning tank 6 through a pipeline; the chloride ion concentration detector can detect the chloride ion concentration of the liquid in the filtrate conditioning tank 6; the filtrate conditioning tank 6 is further communicated with the liquid inlet of the reaction kettle 5 through a pipeline; the liquid with an excessive chloride ion concentration in the filtrate conditioning tank 6 can be sent back into the reaction kettle 5 through a lifting pump; the filtrate conditioning tank 6 is provided with a medicament adding port, a conditioning clear liquid outlet and a sediment separation port; the medicament adding port is used for adding medicament; the sediment separation port of the filtrate conditioning tank 6 is communicated with the inlet of the third-stage filter press 4 through a pipeline; the third-stage filter press 4 can filter and dewater the water-containing sediment discharged from the filtrate conditioning tank 6, thereby obtaining solid calcium carbonate; the conditioning clear liquid outlet of the filtrate conditioning tank 6 is communicated with the liquid inlet of the microfiltration membrane device 8 through a pipeline; the microfiltration membrane in the microfiltration membrane device 8 can perform microfiltration treatment on the conditioning clear liquid discharged from the filtrate conditioning tank 6; the microfiltration clear liquid of the microfiltration membrane device 8 is discharged into the microfiltration water bucket 9 through a pipeline; the microfiltration water bucket 9 is communicated with the liquid inlet of the ultrafiltration membrane device 10 through a pipeline; the microfiltration clear liquid in the microfiltration water bucket 9 can be sent into the ultrafiltration membrane device 10 through a lifting pump; the ultrafiltration membrane of the ultrafiltration membrane device 10 can perform ultrafiltration treatment on the microfiltration clear liquid; the ultrafiltration clear liquid of the ultrafiltration membrane device 10 is discharged into the ultrafiltration water bucket 11 through a pipeline; the ultrafiltration water bucket 11 is communicated with the liquid inlet of the nanofiltration membrane device 12 through a pipeline; the ultrafiltration clear liquid in the ultrafiltration water bucket 11 can be sent into the nanofiltration membrane device 12 through a lifting pump; the nanofiltration membrane of the nanofiltration membrane device 12 can perform nanofiltration treatment on the ultrafiltration clear liquid. After the glycerin residue is diluted, various substances in the glycerin residue dilution liquid are gradually separated, and valuable substances are recycled, thereby effectively improving the glycerin residue resource treatment effect.

[0072] The Fred salt deep processing equipment 13 is provided with a feeding port for feeding solid Fred salt and an auxiliary agent feeding port for feeding auxiliary agent. The Fred salt deep processing equipment 13 can make the solid Fred salt produced by the secondary pressure filter 3 into a solid heavy metal capturing agent by adjusting the auxiliary agent. The calcium carbonate washing and purification equipment 14 can wash and remove impurities from the solid substance containing calcium carbonate produced by the third pressure filter 4, so as to obtain a high-purity solid refined calcium carbonate product. The ultrafiltration concentrated liquid outlet of the ultrafiltration membrane device 10 is connected to the feeding port of the high-polymer polyglycerol deep processing equipment 15 through a pipeline. The ultrafiltration concentrated liquid can be discharged into the high-polymer polyglycerol deep processing equipment 15. The high-polymer polyglycerol deep processing equipment 15 can make the high-polymer polyglycerol in the ultrafiltration concentrated liquid into a liquid cement grinding aid by adjusting the auxiliary agent. The nanofiltration concentrated liquid outlet and the nanofiltration filtrate outlet of the nanofiltration membrane device 12 are respectively connected to the liquid inlets of the low-polymer polyglycerol deep processing equipment 16 and the glycerol solution deep processing equipment 17 through pipelines. The nanofiltration concentrated liquid and the nanofiltration filtrate can be respectively discharged into the low-polymer polyglycerol deep processing equipment 16 and the glycerol solution deep processing equipment 17. The low-polymer polyglycerol deep processing equipment 16 is provided with ion resin. The ion resin can remove inorganic salts in the nanofiltration concentrated liquid. Finally, a liquid refined polyglycerol is obtained. The glycerol solution deep processing equipment 17 can make the nanofiltration filtrate into a liquid water treatment carbon source by adjusting the auxiliary agent. The Fred salt, calcium carbonate, high-polymer polyglycerol, low-polymer polyglycerol and glycerol solution separated during the gradual processing of the glycerol residue dilution liquid are respectively deep-processed. Finally, products that can be directly sold and used are produced, realizing greater economic value.

[0073] The glycerol residue dilution tank 1, the reaction kettle 5 and the filtrate conditioning tank 6 are respectively provided with a stirrer 7 for stirring the mixture. The mixture is stirred by the stirrer 7 to make the mixture more uniform.

Claims

1. A process for recycling glycerol residue, characterized in that: Includes the following steps: Step 1: Diluting the glycerin residue: Dilute the glycerol residue, whose inorganic salt components are mainly chloride salts, with water; Step 2: Filtration and impurity removal: The diluted glycerol residue was filtered to remove colloidal impurities. Step 3: Dechlorination using the Freund's salt method: The filtered glycerol residue dilution is pumped into a reaction vessel, and calcium oxide and sodium aluminate are added to the reaction vessel to generate Fred salt. The Fred salt precipitate and supernatant are separated. The Fred salt precipitate is recycled and the supernatant flows out. The dosage of calcium oxide and sodium aluminate is n(Ca):n(Al):n(Cl) = 5~20:2~5:

1. Step 4: Conditioning the filtrate: The chloride ion content of the supernatant after separating the Fred salt precipitate in step three was determined. If the chloride ion content is >500mg / L, repeat step three; If the chloride ion content is ≤500mg / L, sulfuric acid is added to adjust the pH of the supernatant to neutral. At the same time, sodium carbonate is added to react with calcium ions in the supernatant after separating Fred salt precipitate to form calcium carbonate. The amount of sodium carbonate added is based on the standard that no further precipitation is produced when sodium carbonate is added to the supernatant after separating Fred salt precipitate. The calcium carbonate precipitate is separated, separated, and recycled. Step 5: Microfiltration to remove adhesive: The supernatant produced in step four is filtered using a microfiltration membrane to separate large molecular organics with a molecular weight greater than 1 million from the residual colloids into the microfiltration concentrate, thus obtaining the microfiltration clear liquid. Step Six: Ultrafiltration Separation The microfiltrate was filtered using an ultrafiltration membrane to separate high-polymerization-degree polymeric glycerol with a molecular weight of over 1000 into the ultrafiltrate concentrate for recovery as a raw material for liquid cement grinding aid, while simultaneously obtaining the ultrafiltrate. Step 7: Nanofiltration separation: The ultrafiltrate is filtered using a nanofiltration membrane to separate low-polymerization degree glycerol with a molecular weight of 200-1000 along with sulfate into the nanofiltration concentrate for recycling. At the same time, a nanofiltration solution with glycerol as the main component is obtained, which is used as a glycerol solution.

2. The glycerol residue recycling process according to claim 1, characterized in that: In step one, when diluting the glycerol residue, whose inorganic salt component is mainly chloride salt, with water, the specific gravity is controlled between 1 and 1.05, and the salinity is controlled between 5000 and 50000 mg / L.

3. The glycerol residue recycling process according to claim 1, characterized in that: In step two, a filter press is used to filter the glycerol dilution solution from step one to remove colloidal impurities.

4. The glycerol residue recycling process according to claim 1, characterized in that: In step three, after adding the diluted glycerol residue to the reactor, the stirrer of the reactor is started, the stirrer speed is 80-500 r / min, and the temperature of the diluted glycerol residue in the reactor is controlled at 10-30℃. Then, calcium oxide and sodium aluminate are added to carry out the reaction.

5. The glycerol residue recycling process according to claim 1, characterized in that: The Fred salt precipitate obtained in step three is separated by pressure filtration and then recycled as a raw material for heavy metal capture agent.

6. The glycerol residue recycling process according to claim 1, characterized in that: The calcium carbonate precipitate separated in step four is purified by washing to obtain refined calcium carbonate for industrial production.

7. The glycerol residue recycling process according to claim 1, characterized in that: Refined polyglycerol for industrial production is obtained by adsorbing inorganic salts from the nanofiltration concentrate obtained in step seven using an ion exchange resin.

8. A glycerol residue recycling treatment system for the glycerol residue recycling process according to any one of claims 1-7, characterized in that: The system includes a glycerol residue dilution tank (1), a primary filter press (2), a secondary filter press (3), a tertiary filter press (4), a reaction vessel (5), a filtrate conditioning tank (6), a chloride ion concentration detector, a microfiltration membrane device (8), a microfiltration product water tank (9), an ultrafiltration membrane device (10), an ultrafiltration product water tank (11), and a nanofiltration membrane device (12). The glycerol residue dilution tank is connected to the inlet of the primary filter press via a pipeline. The diluted glycerol residue in the glycerol residue dilution tank can be pumped into the filter press via a booster pump. The filter press can filter the diluted glycerol residue to remove colloidal impurities. The filter outlet of the filter press is connected to the inlet of the reaction vessel via a pipeline. The filtrate is then fed into the reactor. The reactor is also equipped with a reagent inlet, a supernatant outlet, and a sediment outlet that can be opened and closed. The reagent inlet is used to add reagents. The supernatant outlet is used to discharge the supernatant formed after sedimentation in the reactor. The sediment outlet is used to discharge the sediment at the bottom of the reactor. The sediment outlet of the reactor is connected to the inlet of a secondary filter press through a pipeline. The secondary filter press can filter and dehydrate the water-containing sediment discharged from the reactor to obtain solid fructose. The supernatant outlet of the reactor is connected to the inlet of the filtrate conditioning tank through a pipeline. A chloride ion concentration detector can monitor the concentration of chloride ions in the filtrate conditioning tank. The liquid undergoes chloride ion concentration detection. The filtrate conditioning tank is also connected to the inlet of the reaction vessel via a pipeline. Liquid in the filtrate conditioning tank with excessive chloride ion concentration can be returned to the reaction vessel via a booster pump. The filtrate conditioning tank is equipped with a dosing port, a conditioning clear liquid outlet, and a sedimentation separation port. The dosing port is used to add chemicals. The sedimentation separation port of the filtrate conditioning tank is connected to the inlet of a three-stage filter press via a pipeline. The three-stage filter press can dehydrate the water-containing sediment discharged from the filtrate conditioning tank to obtain solid calcium carbonate. The conditioning clear liquid outlet of the filtrate conditioning tank is connected to the inlet of a microfiltration membrane device via a pipeline. The microfiltration membrane device contains microfiltration... The membrane can perform microfiltration treatment on the clarified liquid discharged from the filtrate conditioning tank. The microfiltrate from the microfiltration membrane device is discharged into the microfiltration product tank through a pipeline. The microfiltration product tank is connected to the inlet of the ultrafiltration membrane device through a pipeline. The microfiltrate in the microfiltration product tank can be pumped into the ultrafiltration membrane device through a booster pump. The ultrafiltration membrane of the ultrafiltration membrane device can perform ultrafiltration treatment on the microfiltrate. The ultrafiltration product from the ultrafiltration membrane device is discharged into the ultrafiltration product tank through a pipeline. The ultrafiltration product tank is connected to the inlet of the nanofiltration membrane device through a pipeline. The ultrafiltration product in the ultrafiltration product tank can be pumped into the nanofiltration membrane device through a booster pump. The nanofiltration membrane of the nanofiltration membrane device can perform nanofiltration treatment on the ultrafiltrate.

9. The glycerol residue recycling system according to claim 8, characterized in that: The equipment also includes a Fred salt deep processing device (13), a calcium carbonate washing and purification device (14), a high-polymerization-degree polymeric glycerol deep processing device (15), a low-polymerization-degree polymeric glycerol deep processing device (16), and a glycerol solution deep processing device (17). The Fred salt deep processing device is equipped with a feed inlet for adding solid Fred salt and an additive inlet for adding additives. The Fred salt deep processing device can process the solid Fred salt produced by the secondary filter press into a solid heavy metal scavenging agent by adjusting the additives. The calcium carbonate washing and purification device can wash and remove impurities from the calcium carbonate-containing solid material produced by the tertiary filter press to obtain a high-purity solid refined calcium carbonate product. The ultrafiltration concentrate outlet of the ultrafiltration membrane device is connected to the feed inlet of the high-polymerization-degree polymeric glycerol deep processing device through a pipeline. The ultrafiltration concentrate can be discharged into a high-polymerization-degree polyglycerol deep processing device. This device can use additives to adjust the high-polymerization-degree polyglycerol in the ultrafiltration concentrate to produce a liquid cement grinding aid. The nanofiltration membrane device's nanofiltration concentrate outlet and nanofiltration filtrate outlet are respectively connected to the inlets of a low-polymerization-degree polyglycerol deep processing device and a glycerol solution deep processing device via pipelines. The nanofiltration concentrate and nanofiltration filtrate can be discharged into the low-polymerization-degree polyglycerol deep processing device and the glycerol solution deep processing device, respectively. The low-polymerization-degree polyglycerol deep processing device contains an ion exchange resin, which can filter inorganic salts from the concentrate, ultimately obtaining refined liquid polyglycerol. The glycerol solution deep processing device can use additives to adjust the nanofiltration filtrate to produce a liquid water treatment carbon source.

10. The glycerol residue recycling system according to claim 8, characterized in that: The glycerol residue dilution tank, reaction vessel, and filtrate conditioning tank are all equipped with stirrers (7) for stirring the mixture.

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