A process for treating wastewater generated during glycine production

Abstract

The present invention relates to the technical field of wastewater treatment, and proposes a treatment process for wastewater produced by producing glycine, comprising the following steps: S1, removing methanol from the wastewater produced by producing glycine by rectification, and obtaining a rectification mother liquor; S2, evaporating, concentrating, and crystallizing the rectification mother liquor to obtain ammonium chloride solid and waste liquid; S3, adding an ammonia nitrogen remover to the waste liquid for adsorption and flocculation, filtering, and recovering the filter residue; the ammonia nitrogen remover includes the following raw materials of weight parts: 10-15 parts of polymerized ferric sulfate, 40-50 parts of modified zeolite, 5-10 parts of polyacrylamide, 8-10 parts of melamine, 1-2 parts of fatty alcohol polyoxyethylene ether, and 10-15 parts of metal oxides; the modified zeolite is zeolite modified by N-(2-oxirane methyl) carbamate. Through the above technical scheme, the problem of high ammonia nitrogen content in wastewater produced by glycine in the related art is solved.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, and in particular to a process for treating wastewater generated in the production of glycine. Background Art

[0002] As an important organic synthesis intermediate and raw material, glycine is widely used in medicine, pesticides, organic synthesis and biochemical research. However, a large amount of wastewater is generated in the production process of glycine, which contains a large amount of pollutants, such as ammonium chloride, hexamethylenetetramine, ammonia nitrogen, formaldehyde and methanol. If not effectively treated, these pollutants will have a serious impact on the environment. Treatment of glycine wastewater can not only effectively reduce the impact of pollutants on the environment and protect water resources, but also reduce the generation of waste by recovering useful components in wastewater (such as ammonium chloride), realizing resource reuse and saving resources.

[0003] At present, the treatment of glycine wastewater mainly adopts the evaporation process. After the methanol is evaporated, the ammonium chloride solid is recovered by evaporation, concentration, cooling and crystallization. However, the wastewater after removing the ammonium chloride is dark in color and difficult to treat. Therefore, the development of a wastewater treatment process for glycine production is a problem that needs to be solved at present. Summary of the invention

[0004] The invention provides a treatment process for wastewater generated by producing glycine, which solves the problem of high ammonia nitrogen content in wastewater generated by glycine in the related art.

[0005] The technical solution of the present invention is as follows:

[0006] The present invention provides a process for treating wastewater generated by producing glycine, comprising the following steps:

[0007] S1, removing methanol from the wastewater produced by the production of glycine by distillation to obtain a distillation mother liquor;

[0008] S2, evaporating, concentrating and crystallizing the rectification mother liquor to obtain ammonium chloride solid and waste liquid;

[0009] S3, adding an ammonia nitrogen remover to the waste liquid for adsorption and flocculation, filtering, and recovering the filter residue;

[0010] The ammonia nitrogen remover comprises the following raw materials in parts by weight: 10-15 parts of polyferric sulfate, 40-50 parts of modified zeolite, 5-10 parts of polyacrylamide, 8-10 parts of melamine, 1-2 parts of fatty alcohol polyoxyethylene ether, and 10-15 parts of metal oxide;

[0011] The modified zeolite is obtained by modifying zeolite with N-(2-oxiranylmethyl)carbamate.

[0012] In the present invention, the waste liquid in step S3 is subjected to adsorption and flocculation, and the filtrate obtained after filtration can be reused in production, thereby reducing the discharge of waste water and saving production costs.

[0013] As a further technical solution, the input amount of the ammonia nitrogen remover is 0.8~1.4g / L.

[0014] As a further technical solution, the added amount of the N-(2-oxiranylmethyl)carbamate is 5% to 8% of the mass of the zeolite.

[0015] In the present invention, the adsorption of ammonia nitrogen compounds by zeolite is further improved by limiting the addition amount of N-(2-oxiranylmethyl)carbamate to 5% to 8% of the mass of zeolite.

[0016] As a further technical solution, the particle size of the zeolite is 100-500 meshes.

[0017] As a further technical solution, the preparation method of the modified zeolite comprises the following steps: after acidifying the zeolite, methanol and N-(2-oxiranylmethyl)carbamate are added for modification to obtain the modified zeolite.

[0018] As a further technical solution, the reagent used in the acidification is one or both of acetic acid and trifluoroacetic acid.

[0019] As a further technical solution, the mass volume ratio of the zeolite to the acidifying agent is 1 g:0.5 mL.

[0020] As a further technical solution, the acidification time is 1 to 2 hours.

[0021] As a further technical solution, the modification temperature is 35-45°C, and the modification time is 5-7h.

[0022] As a further technical solution, the metal oxide includes one or more of zirconium oxide, calcium oxide, and aluminum oxide.

[0023] As a further technical solution, the metal oxide consists of zirconium oxide and calcium oxide.

[0024] In the present invention, by limiting the metal oxide to consist of zirconium oxide and calcium oxide, the efficiency of the ammonia nitrogen remover is further improved.

[0025] As a further technical solution, the mass ratio of zirconium oxide to calcium oxide is 1:1.

[0026] As a further technical solution, the crystal form of the zirconium oxide includes one or both of a monoclinic crystal form and a cubic crystal form.

[0027] As a further technical solution, the zirconium oxide consists of monoclinic zirconium oxide and cubic zirconium oxide.

[0028] As a further technical solution, the mass ratio of the monoclinic zirconia to the cubic zirconia is 1:2~4.

[0029] In the present invention, by limiting the zirconium oxide to consist of cubic crystal and monoclinic crystal, the removal efficiency of ammonia nitrogen compounds is further improved.

[0030] As a further technical solution, the mass ratio of the monoclinic zirconia to the cubic zirconia is 1:3.

[0031] As a further technical solution, the preparation method of the ammonia nitrogen remover includes the following steps: mixing and ball-milling polyferric sulfate, modified zeolite, polyacrylamide, melamine, fatty alcohol polyoxyethylene ether, and metal oxide to obtain the ammonia nitrogen remover.

[0032] As a further technical solution, the polyacrylamide is cationic polyacrylamide.

[0033] As a further technical solution, the fatty alcohol polyoxyethylene ether includes one or two of lauryl alcohol polyoxyethylene ether and isomeric tridecanol polyoxyethylene ether.

[0034] As a further technical solution, the evaporation in S2 is double-effect evaporation.

[0035] The working principle and beneficial effects of the present invention are:

[0036] In the present invention, wastewater generated by glycine production is treated by distillation, evaporation, flocculation and filtration processes, thereby reducing the content of ammonia nitrogen compounds in the wastewater, and by adding an ammonia nitrogen remover composed of polyferric sulfate, zeolite modified by N-(2-oxiranylmethyl)carbamate, polyacrylamide, melamine and fatty alcohol polyoxyethylene ether, pollutants such as ammonia nitrogen in the wastewater are flocculated and precipitated, thereby further reducing the content of pollutants in the wastewater, thereby solving the problem of high content of ammonia nitrogen pollutants in the wastewater generated by glycine production. DETAILED DESCRIPTION

[0037] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] In the following examples and comparative examples:

[0039] Polyferric sulfate, 20% content, purchased from Henan Taiyuan Environmental Protection Technology Co., Ltd.;

[0040] Cationic polyacrylamide, molecular weight 12 million, purchased from Langfang Jiaye Chemical Co., Ltd.;

[0041] Lauryl alcohol polyoxyethylene ether, model SY-D2, purchased from Shandong Senya New Materials Co., Ltd.;

[0042] Isomeric tridecanol polyoxyethylene ether, model 1305, purchased from Jinan Baoliyuan Chemical Co., Ltd.;

[0043] Zirconia, cubic crystal, was purchased from Shanghai Yingcheng New Materials Co., Ltd.;

[0044] Zirconia, monoclinic, was purchased from Hebei Yuehan Metal Materials Sales Co., Ltd.;

[0045] Zeolite, particle size 100-500 mesh, was purchased from Lingshou County Xuhai Mineral Products Trading Co., Ltd.

[0046] Example 1

[0047] A process for treating wastewater generated by producing glycine comprises the following steps:

[0048] S1, removing methanol from the wastewater produced by the production of glycine by distillation to obtain a distillation mother liquor;

[0049] S2, double-effect evaporation, concentration and crystallization of the rectification mother liquor to obtain ammonium chloride solid and waste liquid;

[0050] S3. Add ammonia nitrogen remover (input amount 0.8g / L) to the waste liquid for adsorption and flocculation, filter, recover the filter residue, and reuse the filtrate in production.

[0051] The preparation method of the ammonia nitrogen remover comprises the following steps:

[0052] A1. Add 80 g of zeolite (100 mesh) to 200 mL of acetic acid aqueous solution (volume concentration 20%), stir for 1 h, filter and dry to obtain acidified zeolite, add the acidified zeolite to 800 mL of methanol, add 1.6 g of N-(2-oxiranylmethyl)carbamate, stir at 35 ° C for 7 h, filter and dry to obtain modified zeolite;

[0053] A2. 10 parts of polyferric sulfate, 40 parts of modified zeolite, 5 parts of cationic polyacrylamide, 8 parts of melamine, 1 part of lauryl alcohol polyoxyethylene ether and 10 parts of metal oxide are mixed and ball-milled to obtain an ammonia nitrogen remover, wherein the metal oxide is zirconium oxide (monoclinic).

[0054] Example 2

[0055] A process for treating wastewater generated by producing glycine comprises the following steps:

[0056] S1, removing methanol from the wastewater produced by the production of glycine by distillation to obtain a distillation mother liquor;

[0057] S2, double-effect evaporation, concentration and crystallization of the rectification mother liquor to obtain ammonium chloride solid and waste liquid;

[0058] S3. Add ammonia nitrogen remover (input amount 1g / L) to the waste liquid for adsorption and flocculation, filter, recover the filter residue, and reuse the filtrate in production.

[0059] The preparation method of the ammonia nitrogen remover comprises the following steps:

[0060] A1. Add 80 g of zeolite (325 mesh) to 200 mL of trifluoroacetic acid aqueous solution (volume concentration 20%), stir for 2 h, filter and dry to obtain acidified zeolite, add the acidified zeolite to 800 mL of methanol, add 1.6 g of N-(2-oxiranylmethyl)carbamate, stir for 6 h at 40 ° C, filter and dry to obtain modified zeolite;

[0061] A2. Mix 12 parts of polyferric sulfate, 45 parts of modified zeolite, 7 parts of cationic polyacrylamide, 9 parts of melamine, 1.5 parts of isomeric tridecanol polyoxyethylene ether, and 12 parts of metal oxide and perform ball milling to obtain an ammonia nitrogen remover, wherein the metal oxide is calcium oxide.

[0062] Example 3

[0063] A process for treating wastewater generated by producing glycine comprises the following steps:

[0064] S1, removing methanol from the wastewater produced by the production of glycine by distillation to obtain a distillation mother liquor;

[0065] S2, double-effect evaporation, concentration and crystallization of the rectification mother liquor to obtain ammonium chloride solid and waste liquid;

[0066] S3. Add ammonia nitrogen remover (input amount 1.4g / L) to the waste liquid for adsorption and flocculation, filter, recover the filter residue, and reuse the filtrate in production.

[0067] The preparation method of the ammonia nitrogen remover comprises the following steps:

[0068] A1. Add 80 g of zeolite (500 mesh) to 200 mL of trifluoroacetic acid aqueous solution (volume concentration 20%), stir for 2 h, filter and dry to obtain acidified zeolite, add the acidified zeolite to 800 mL of methanol, add 1.6 g of N-(2-oxiranylmethyl)carbamate, stir for 5 h at 45 ° C, filter and dry to obtain modified zeolite;

[0069] A2. 15 parts of polyferric sulfate, 50 parts of modified zeolite, 10 parts of cationic polyacrylamide, 10 parts of melamine, 2 parts of isomeric tridecanol polyoxyethylene ether and 15 parts of metal oxide are mixed and ball-milled to obtain an ammonia nitrogen remover, wherein the metal oxide is aluminum oxide.

[0070] Example 4

[0071] The only difference between this embodiment and embodiment 1 is that the added amount of N-(2-oxiranylmethyl)carbamate is 8 g.

[0072] Example 5

[0073] The only difference between this embodiment and embodiment 1 is that the added amount of N-(2-oxiranylmethyl)carbamate is 4 g.

[0074] Example 6

[0075] The only difference between this embodiment and embodiment 1 is that the added amount of N-(2-oxiranylmethyl)carbamate is 4.8 g.

[0076] Example 7

[0077] The only difference between this embodiment and embodiment 1 is that the added amount of N-(2-oxiranylmethyl)carbamate is 6.4 g.

[0078] Example 8

[0079] The only difference between this embodiment and embodiment 6 is that the metal oxide is calcium oxide.

[0080] Example 9

[0081] The only difference between this embodiment and embodiment 6 is that the metal oxide is calcium oxide and zirconium oxide (monoclinic) in a mass ratio of 1:1.

[0082] Example 10

[0083] The only difference between this embodiment and Embodiment 9 is that the metal oxides are aluminum oxide and zirconium oxide (monoclinic) in a mass ratio of 1:1.

[0084] Embodiment 11

[0085] The only difference between this embodiment and Embodiment 9 is that the metal oxide is calcium oxide and zirconium oxide (cubic crystal) in a mass ratio of 1:1.

[0086] Example 12

[0087] The only difference between this embodiment and Embodiment 9 is that the metal oxides are calcium oxide and zirconium oxide in a mass ratio of 1:1, wherein the zirconium oxide is zirconium oxide (monoclinic) and zirconium oxide (cubic) in a mass ratio of 1:1.

[0088] Embodiment 13

[0089] The only difference between this embodiment and Embodiment 12 is that the zirconium oxide is zirconium oxide (monoclinic) and zirconium oxide (cubic) in a mass ratio of 1:5.

[0090] Embodiment 14

[0091] The only difference between this embodiment and Embodiment 12 is that the zirconium oxide is zirconium oxide (monoclinic) and zirconium oxide (cubic) in a mass ratio of 1:2.

[0092] Embodiment 15

[0093] The only difference between this embodiment and Embodiment 12 is that the zirconium oxide is zirconium oxide (monoclinic) and zirconium oxide (cubic) in a mass ratio of 1:3.

[0094] Example 16

[0095] The only difference between this embodiment and Embodiment 12 is that the zirconium oxide is zirconium oxide (monoclinic) and zirconium oxide (cubic) in a mass ratio of 1:4.

[0096] Comparative Example 1

[0097] The only difference between this comparative example and Example 1 is that the preparation method of the ammonia nitrogen remover comprises the following steps:

[0098] An ammonia nitrogen remover is obtained by mixing and ball-milling 10 parts of polyferric sulfate, 40 parts of zeolite (100 mesh), 5 parts of cationic polyacrylamide, 8 parts of melamine, 1 part of lauryl alcohol polyoxyethylene ether and 10 parts of zirconium oxide (monoclinic).

[0099] The wastewater produced by the production of glycine in Examples 1 to 16 and Comparative Example 1 was tested for ammonia nitrogen content before and after treatment according to the determination method in GB / T 34532-2017 "Determination of ammonia nitrogen content in coking wastewater - formaldehyde method" (the filtrate obtained after filtration in step S3 after treatment), and COD was tested according to the determination method in HJ 828-2017 "Determination of chemical oxygen demand in water - dichromate method", and the test results are shown in Table 1.

[0100] Table 1 Test results of Examples 1 to 16 and Comparative Example 1 before and after treatment of glycine wastewater

[0101]

[0102] Compared with Example 1, unmodified zeolite was added in Comparative Example 1. As a result, the ammonia nitrogen content and COD in Comparative Example 1 were higher than those in Example 1, indicating that the removal rates of ammonia nitrogen and COD could be improved by modifying zeolite with N-(2-oxiranylmethyl)carbamate.

[0103] Compared with Example 1, Examples 4 to 7 change the amount of N-(2-oxiranylmethyl)carbamate added. As a result, the ammonia nitrogen content and COD in Examples 5 to 7 are lower than those in Example 1 and Example 4, indicating that when the amount of N-(2-oxiranylmethyl)carbamate added is 5% to 8% of the mass of the zeolite, the removal rates of ammonia nitrogen and COD can be further improved.

[0104] Compared with Example 6, Examples 8 to 10 changed the composition of the metal oxide. As a result, the ammonia nitrogen content and COD in Example 9 were lower than those in Examples 6, 8, and 10, indicating that when the metal oxide is composed of zirconium oxide and calcium oxide, the removal rates of ammonia nitrogen and COD can be further improved.

[0105] Compared with Example 9, Examples 11~12 change the composition of the zirconium oxide crystal form. As a result, the ammonia nitrogen content and COD in Example 12 are lower than those in Examples 9 and 11, indicating that when zirconium oxide is composed of monoclinic and cubic crystal forms, the removal rates of ammonia nitrogen and COD can be further improved.

[0106] Compared with Example 12, Examples 13 to 16 change the mass ratio of monoclinic zirconia and cubic zirconia. As a result, the ammonia nitrogen content and COD in Examples 14 to 16 are lower than those in Examples 12 and 13, indicating that when the zirconia is composed of monoclinic zirconia and cubic zirconia in a mass ratio of 1:2 to 4, the ammonia nitrogen and COD removal rates can be further improved. By comparing Examples 14 to 16, it is found that the ammonia nitrogen content and COD in Example 15 are lower than those in Examples 14 and 16, indicating that when the mass ratio of monoclinic zirconia to cubic zirconia is 1:3, the ammonia nitrogen content and COD of the wastewater produced by glycine are the lowest after treatment.

[0107] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A process for treating wastewater generated by producing glycine, characterized in that: The following steps are involved: S1, removing methanol from the wastewater produced by the production of glycine by distillation to obtain a distillation mother liquor; S2, evaporating, concentrating and crystallizing the rectification mother liquor to obtain ammonium chloride solid and waste liquid; S3, adding an ammonia nitrogen remover to the waste liquid for adsorption and flocculation, filtering, and recovering the filter residue; The ammonia nitrogen remover is composed of the following raw materials in parts by weight: 10-15 parts of polyferric sulfate, 40-50 parts of modified zeolite, 5-10 parts of polyacrylamide, 8-10 parts of melamine, 1-2 parts of fatty alcohol polyoxyethylene ether, and 10-15 parts of metal oxide; The modified zeolite is obtained by modifying zeolite with N-(2-oxiranylmethyl)carbamate; The amount of N-(2-oxiranylmethyl)carbamate added is 5% to 8% of the mass of the zeolite; The preparation method of the modified zeolite comprises the following steps: acidifying the zeolite, adding methanol and N-(2-oxiranylmethyl)carbamate to modify the zeolite, and obtaining the modified zeolite; The metal oxide includes one or more of zirconium oxide, calcium oxide, and aluminum oxide; The crystal form of the zirconium oxide includes one or both of a monoclinic crystal form and a cubic crystal form.

2. A process for treating wastewater generated by the production of glycine according to claim 1, characterized in that: The input amount of the ammonia nitrogen remover is 0.8~1.4g / L.

3. A process for treating wastewater generated by the production of glycine according to claim 1, characterized in that: The particle size of the zeolite is 100-500 meshes.

4. A process for treating wastewater generated by the production of glycine according to claim 1, characterized in that: The metal oxide consists of zirconium oxide and calcium oxide.

5. The process for treating wastewater generated by the production of glycine according to claim 1, characterized in that: The fatty alcohol polyoxyethylene ether includes one or two of lauryl alcohol polyoxyethylene ether and isomeric tridecanol polyoxyethylene ether.

6. A process for treating wastewater generated by the production of glycine according to claim 1, characterized in that: The evaporation in S2 is double-effect evaporation.

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