CN-116966849-B - Sodium carbonate recovery system and method for recovering sodium carbonate from PTA organic residues by utilizing same

CN116966849BCN 116966849 BCN116966849 BCN 116966849BCN-116966849-B

Abstract

The invention provides a sodium carbonate recovery system and a method for recovering sodium carbonate from PTA organic residues by using the system, wherein a dissolving tank A, a filter, an evaporation feed tank and an evaporator A are sequentially connected in the system; the evaporator A, the evaporator B and the recovery tank are sequentially connected, the evaporator A, the thickener A, the centrifugal machine A and the screw A are sequentially connected, the screw A is respectively connected with the drying system and the dissolution tank B, the evaporator B, the thickener B, the centrifugal machine B and the screw B are sequentially connected, the screw B is connected with the dissolution tank B, the evaporator A is connected with the condenser A, the condenser A is respectively connected with the dissolution tank A and the dissolution tank B, the evaporator B, the condenser B and the dissolution tank B are sequentially connected, and the dissolution tank B is connected with the main device system. In this recovery system, not only effectively retrieved sodium carbonate solid, and can be nimble according to the demand to sodium carbonate solution concentration adjustment, simultaneously, to water full cycle utilization in this recovery system, reduce the wasting of resources, practice thrift the cost.

Inventors

SONG XIAOJUN
ZHAO XINGUO
CAO SHANWEN
JIANG BO
LONG ZHAOJUN
LI BING

Assignees

海南逸盛石化有限公司
浙江利星科技股份有限公司

Dates

Publication Date: 20260512
Application Date: 20230620

Claims (7)

1. A method for recycling sodium carbonate from PTA organic residues by utilizing a sodium carbonate recycling system, which is characterized by comprising the following steps: (1) Placing ash residue obtained after burning PTA organic residues by an incinerator into a dissolving tank A, mixing with water, wherein the mass ratio of the ash residue to the water is 1:3.0-5.0, and obtaining a solution A; (2) Filtering the solution A by a filter to remove insoluble solid cobalt, manganese and corrosive ions to obtain a solution B only containing sodium carbonate and sodium bromide; (3) Pumping the solution B in the evaporation feed tank into an evaporator A by using a pump B for concentration, and conveying the solution to a thickener A for continuous concentration when the concentration of sodium carbonate in the solution is between 30 and 33 percent; (4) The filter cake separated by the centrifuge A is selectively conveyed to a dissolving tank B according to the requirement to prepare sodium carbonate solution with the concentration of 20-25 percent, or sodium carbonate solid is obtained when the filter cake is conveyed to a drying system; (5) Extracting supernatant liquid in the evaporator A into the evaporator B, further concentrating, recovering sodium carbonate and improving impurity concentration; (6) The solid in the evaporator B is pumped out to a refrigerating system for cooling so as to reduce the solubility of sodium carbonate and separate out more sodium carbonate; (7) Concentrating the frozen liquid through a thickener B solid, and then, separating solid and liquid in a centrifuge B; (8) The solid is sent to a dissolving tank B through a screw B to be dissolved to obtain sodium carbonate solution, and the sodium carbonate solution is recycled in a system; The sodium carbonate recovery system comprises a dissolving tank A, a filter, an evaporation feed tank, an evaporator A, a thickener A, a centrifuge A, a screw A, a drying system, a dissolving tank B, a condenser A, a vacuumizing system A, an evaporator B, a thickener B, a centrifuge B, a screw B, a vacuumizing system B, a recovery tank, a main device system and a condenser B; the dissolution tank A is connected with a filter, a liquid outlet of the filter is connected with an evaporation feed tank, and the evaporation feed tank is connected with the evaporator A; The solid outlet at the bottom of the evaporator A is connected with a thickener A, the thickener A is connected with a centrifugal machine A, the centrifugal machine A is connected with a screw A, the outlet of the screw A is divided into two paths, one path is connected with a drying system, and the other path is connected with a dissolving tank B; the solid outlet at the bottom of the evaporator B is connected with a thickener B, the thickener B is connected with a centrifugal machine B, the centrifugal machine B is connected with a screw B, and the screw B is connected with a dissolution tank B; The gas phase outlet of the evaporator A is connected with the condenser A, the condensate outlet of the condenser A is divided into two paths, one path is connected with the dissolution tank A, and the other path is connected with the dissolution tank B; The gas phase outlet of the evaporator B is connected with a condenser B, and the condensate outlet of the condenser B is connected with a dissolving tank B; the dissolving tank B is connected with a main device system; a pump A is arranged on a connecting pipeline between the dissolving tank A and the filter, and a pump B is arranged on a connecting pipeline between the evaporation feed tank and the evaporator A; and a refrigerating system is arranged on a connecting pipeline between the solid outlet at the bottom of the evaporator B and the thickener B.
2. The method for recovering sodium carbonate from organic PTA residues by using a sodium carbonate recovery system according to claim 1, wherein a pump C is arranged at a condensate outlet of a condenser a, and a pump D is arranged at a condensate outlet of a condenser B.
3. The method for recovering sodium carbonate from PTA organic residues by using a sodium carbonate recovery system according to claim 1, wherein a vacuum system A is connected to a condenser A, and a vacuum system B is connected to a condenser B.
4. The method for recovering sodium carbonate from organic PTA residue using a sodium carbonate recovery system according to claim 1, wherein a pump E is installed on a connection line of the dissolution tank B and the main system.
5. The method for recovering sodium carbonate from organic PTA residue using a sodium carbonate recovery system according to claim 1, wherein the screw A is a bi-directional screw and the screw B is a unidirectional screw.
6. The process for recovering sodium carbonate from PTA organic residue using a sodium carbonate recovery system according to claim 1, wherein the filter is a sintered filter.
7. The process for recovering sodium carbonate from PTA organic residue using a sodium carbonate recovery system according to claim 1, wherein the drying system is a rake dryer.

Description

Sodium carbonate recovery system and method for recovering sodium carbonate from PTA organic residues by utilizing same Technical Field The invention relates to the technical field of PTA (pure terephthalic acid) preparation residue treatment, in particular to a sodium carbonate recovery system and a method for recovering sodium carbonate from PTA organic residues by using the same. Background Terephthalic Acid (PTA), which is the dicarboxylic acid with the largest yield, is an important organic synthetic monomer in the chemical industry, is mainly used for producing polyethylene terephthalate (PET) and bottle chip polyester, and can be used as a plasticizer raw material, so that the terephthalic acid is widely applied in industry. The high temperature liquid phase oxidation method mainly comprises an oxidation process and a hydrofining process, in order to ensure that the method is carried out smoothly, materials in equipment and pipelines are prevented from being blocked, alkali liquor is generally required to be used for cleaning, waste liquid and residues in the oxidation process and other waste materials carried out by running, overflowing, dripping and leaking on site and systems are finally discharged into a waste collection tank, and the waste materials are collectively called PTA organic residues. The oxidation residue becomes water-soluble substances by adding sodium carbonate or/and sodium hydroxide into the PTA organic residue, meanwhile, metals such as cobalt and manganese in the oxidation residue are converted into precipitates, separation is realized by filtration, filtrate enters a sewage system and is discharged after reaching standards through biochemical treatment, and a large amount of organic acid is wasted and a large amount of wastewater is discharged simultaneously, so that the process has important significance in effectively recycling sodium carbonate, changing waste into valuables, reducing waste and wastewater discharge and reducing cost. Disclosure of Invention Aiming at the defects of the prior art, the invention provides a sodium carbonate recovery system and a method for recovering sodium carbonate from PTA organic residues by using the same, wherein the sodium carbonate recovery system has the advantages of reasonable design, high practicability and convenience in use, in the recovery system, sodium carbonate solids are effectively recovered, the concentration of sodium carbonate solution can be flexibly adjusted according to requirements, and meanwhile, water in the recovery system is fully recycled, so that the resource waste is reduced, and the cost is saved. The method for recycling sodium carbonate from PTA organic residues has the advantages of simplicity, easiness in control and suitability for wide popularization. The method not only can flexibly utilize and collect sodium carbonate, but also can effectively collect sodium carbonate solids from ash residues after burning PTA organic residues. The technical scheme of the invention is as follows: A sodium carbonate recovery system comprises a dissolving tank A, a pump A, a filter, an evaporation feed tank, a pump B, an evaporator A, a thickener A, a centrifuge A, a screw A, a drying system, a dissolving tank B, a condenser A, a pump C, a vacuumizing system A, an evaporator B, a freezing system, a thickener B, a centrifuge B, a screw B, a vacuumizing system B, a pump D, a recovery tank, a pump E, a main device system and a condenser B; the liquid separation flow comprises the following steps: The dissolving tank A is connected with the filter through a pump A; the liquid outlet of the filter is connected with an evaporation feed tank, and the evaporation feed tank is connected with an evaporator A through a pump B; the solid separation flow: the first stage is that the solid at the bottom of an evaporator A is extracted, the evaporator A is connected with a thickener A, the thickener A is connected with a centrifugal machine A, the solid of the centrifugal machine A is discharged to a screw A, and the screw A is sent to a drying system or a dissolving tank B by controlling steering; The second stage, namely extracting the solid at the bottom of the evaporator B, wherein the evaporator B is connected with a refrigerating system, the refrigerating system is connected with a thickener B, the thickener B is connected with a centrifugal machine B, the solid of the centrifugal machine B is discharged to a screw B, and the screw B sends the solid to a dissolving tank B; And (3) evaporation and condensation flow: The first stage, namely connecting the gas phase of the evaporator A with a condenser A, and pumping the condensate of the condenser A back to a dissolving tank A and a dissolving tank B through a pump C to recover the condensate; the second stage, namely connecting the gas phase of the evaporator B with a condenser B, pumping the condensate of the condenser B back to a dissolving tank B through a pump D to recover the