Resourceful treatment process for waste salt in nitromethyl ether production

Abstract

The invention relates to a resourceful treatment process for waste salt in nitromethyl ether production. The process comprises the following steps: introducing a high-salt material into a closed centrifugal machine (850-1200rpm, 55 + / -5 DEG C) to separate solid waste salt and mother liquor; washing the waste salt with 80-90% methanol solution according to the flow ratio of a salt phase to a solvent of 1: 1.2 for 3 times (15 min for each time), and performing vacuum drying at 60 DEG C to obtain industrial sodium chloride with the purity of more than or equal to 95%; after the methanol mother liquor is distilled and recycled, 10% by volume of pure water is added into tower kettle concentrated liquor, after oil-water separation, a water phase is transferred into an environment-friendly treatment system after being subjected to adsorption treatment by 0.1% activated carbon, and an oil phase directly enters the next reduction procedure. According to the process, the wastewater is reduced by 92% (to 0.4 m < 3 > / t product), the recovery rate of sodium chloride is greater than or equal to 85%, the utilization rate of methanol reaches 99.2%, the COD (Chemical Oxygen Demand) of a water phase is reduced by 94%, the treatment cost is saved by 67%, and the subsequent reduction reaction is not influenced. The problem of waste salt pollution is solved, and efficient cyclic utilization of resources is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of nitro methanol ether production waste salt resource processing process. BACKGROUND

[0002] The existing nitro methanol ether production process refers to Chinese patent CN200610085488.8, after reaction, methanol needs to be recovered by distillation, then a large amount of water (usually 3-5 times of the volume of material) is added for washing to remove residual organic matter and salt. This process produces the following problems:

[0003] 1. High-salinity wastewater is difficult to treat: the washing water contains 10-15% sodium chloride and phenolic organic matter, and the COD value is as high as 50000-80000 mg / L, with high treatment cost.

[0004] 2. Resource waste: the sodium chloride content in waste salt is more than 90%, but it is yellow or red due to organic pollution, and cannot be directly utilized.

[0005] 3. Solvent loss: traditional water washing causes methanol residue (2-3%) to enter the wastewater system, increasing raw material consumption. SUMMARY

[0006] The technical problem to be solved by the present application is to provide a resource processing process for waste salt produced in the production of nitro methanol ether, which can recycle waste salt and solvent, improve resource utilization rate and reduce waste.

[0007] To solve the above technical problems, the present application provides a resource processing process for waste salt produced in the production of nitro methanol ether, comprising the following steps:

[0008] (1) Centrifugal separation: high-salinity material produced on the nitro methanol ether production line is directly introduced into a closed centrifuge to separate solid waste salt and mother liquor;

[0009] (2) Salt phase treatment: waste salt is washed with 80-90% methanol solution for 3 times, and white sodium chloride with purity ≥95% is obtained by vacuum drying at 60℃, meeting the GB / T 5462-2015 industrial salt standard;

[0010] (3) Mother liquor treatment: the washed methanol mother liquor is recovered by distillation, the remaining concentrated liquid in the column is discharged and 10% by volume of pure water is added, after stirring, it is separated into layers and oil and water are separated, 0.1% of activated carbon is added to the water phase, and then it is transferred to the environmental protection treatment system, and the oil phase enters the reduction process.

[0011] As a preferred, the working parameters of the centrifuge in step (1) are: rotation speed 850-1200 rpm, and temperature control at 55±5℃.

[0012] As preferred, the flow ratio of methanol to solvent in the step (2) is 1:1.2, and the single washing time is 15 min.

[0013] Advantages of the present application: the resource treatment process of waste salt in nitro methyl ether production can recycle waste salt and solvent, improve resource utilization, reduce waste, and has the following technical effects verified by experiments:

[0014] 1. Wastewater reduction: the high-salt wastewater production is reduced from 5m 3 / t product to 0.4m 3 / t, with a reduction of 92%;

[0015] 2. Resource recovery:

[0016] - The recovery rate of sodium chloride is ≥85%, reaching the industrial first-grade salt standard;

[0017] - The comprehensive utilization rate of methanol is improved to 99.2%;

[0018] 3. Environmental benefits: the COD of the water phase is reduced by 94%, and the treatment cost is saved by 67%;

[0019] 4. Product quality: does not affect the subsequent reduction reaction effect. DETAILED DESCRIPTION

[0020] Example 1:

[0021] A resource treatment process of waste salt in nitro methyl ether production, comprising the following steps:

[0022] (1) Centrifugal separation: the high-salt material generated on the nitro methyl ether production line is directly introduced into a closed centrifuge to separate solid waste salt and mother liquor;

[0023] (2) Salt phase treatment: the waste salt is washed with 80% methanol solution for 3 times, and white sodium chloride with purity ≥95% is obtained by vacuum drying at 60℃, meeting the industrial salt standard of GB / T 5462-2015;

[0024] (3) Mother liquor treatment: the washed methanol mother liquor is recovered by distillation column, the remaining concentrated liquid in the column is discharged and 10% volume of pure water is added, after stirring, it is layered and oil-water separated, 0.1% active carbon is added to the water phase, and then it is transferred to the environmental protection treatment system, and the oil phase enters the reduction process.

[0025] In the step (1), the working parameters of the centrifuge are: speed 850 rpm, and temperature control at 50℃.

[0026] In the step (2), the flow ratio of methanol to solvent in the washing of salt phase is 1:1.2, and the single washing time is 15 min.

[0027] Example Two

[0028] A resourceful treatment process for waste salt produced in nitro methyl ether production, comprising the following steps:

[0029] (1) Centrifugal separation: The high-salt material generated on the nitro methyl ether production line is directly introduced into a closed centrifuge to separate the solid waste salt from the mother liquor;

[0030] (2) Salt phase treatment: The waste salt is washed with 85% methanol solution for 3 times, and vacuum dried at 60°C to obtain white sodium chloride with purity ≥95%, meeting the GB / T 5462-2015 industrial salt standard;

[0031] (3) Mother liquor treatment: The washed methanol mother liquor is recovered by distillation column, the remaining concentrated liquid in the column is discharged and 10% volume of pure water is added, after stirring, it is layered and oil-water separated, 0.1% activated carbon is added to the water phase, and then it is transferred to the environmental protection treatment system, and the oil phase enters the reduction process.

[0032] In the step (1), the working parameters of the centrifuge are: rotation speed 1000 rpm, temperature control at 55°C.

[0033] In the step (2), the flow ratio of methanol washing salt phase to solvent is 1:1.2, and the single washing time is 15 min.

[0034] Example Three

[0035] A resourceful treatment process for waste salt produced in nitro methyl ether production, comprising the following steps:

[0036] (1) Centrifugal separation: The high-salt material generated on the nitro methyl ether production line is directly introduced into a closed centrifuge to separate the solid waste salt from the mother liquor;

[0037] (2) Salt phase treatment: The waste salt is washed with 90% methanol solution for 3 times, and vacuum dried at 60°C to obtain white sodium chloride with purity ≥95%, meeting the GB / T 5462-2015 industrial salt standard;

[0038] (3) Mother liquor treatment: The washed methanol mother liquor is recovered by distillation column, the remaining concentrated liquid in the column is discharged and 10% volume of pure water is added, after stirring, it is layered and oil-water separated, 0.1% activated carbon is added to the water phase, and then it is transferred to the environmental protection treatment system, and the oil phase enters the reduction process.

[0039] In the step (1), the working parameters of the centrifuge are: rotation speed 1200 rpm, temperature control at 60°C.

[0040] In the step (2), the flow ratio of methanol washing salt phase to solvent is 1:1.2, and the single washing time is 15 min.

Claims

1. A process for resourceful treatment of waste salt from nitro methyl ether production, characterized in that, It comprises the following steps: (1) centrifugal separation: the high-salt material produced in the nitro methyl ether production line is directly introduced into a closed centrifuge to separate solid waste salt from mother liquor; (2) salt phase treatment: the waste salt is washed with 80-90% methanol solution for 3 times, and white sodium chloride with purity greater than or equal to 95% and meeting the industrial salt standard GB / T 5462-2015 is obtained by vacuum drying at 60℃; (3) mother liquor treatment: the washed methanol mother liquor is recovered by distillation, the remaining concentrated liquid in the column is discharged and 10% by volume of pure water is added, after stirring, it is layered and oil-water separated, 0.1% of activated carbon by total mass is added to the water phase and then transferred to the environmental protection treatment system, and the oil phase enters the reduction process.

2. A process for resource recovery of waste salt from nitro methyl ether production as claimed in claim 1, wherein: In the step (1), the working parameters of the centrifuge are: rotation speed 850-1200 rpm, temperature control at 55±5℃.

3. A process for resource recovery of waste salt from nitro methyl ether production as claimed in claim 1, wherein: In the step (2), the flow ratio of methanol washing salt phase and solvent is 1:1.2, and the single washing time is 15 min.