CN-224226713-U - Efficient and energy-saving PTA wastewater treatment device

CN224226713UCN 224226713 UCN224226713 UCN 224226713UCN-224226713-U

Abstract

The utility model discloses a high-efficiency energy-saving PTA wastewater treatment device, which comprises a multi-effect evaporation unit, a waste heat recovery unit and a PTA mother liquor heat recovery unit. The multi-effect evaporation unit adopts four-effect evaporators connected in series to realize reverse gradual evaporation and concentration of wastewater, the waste heat recovery unit recovers the waste heat of the system through a parallel heat exchanger and a serial hot water flash tank to provide heat for the evaporators, and the PTA mother liquor heat recovery unit releases heat step by step through a mother liquor flash tank to be supplied to the evaporators. The wastewater is evaporated and concentrated, then enters a crystallizer in front of the furnace for crystallization, and the residue is sent into an alkali incinerator for treatment. The utility model obviously reduces the energy consumption through multi-effect evaporation and waste heat cascade utilization, does not need extra steam, can also be used for power generation by waste heat, has the advantages of high efficiency, energy conservation and low material consumption, and is suitable for large-scale treatment of PTA wastewater.

Inventors

DUAN HONGFENG
YANG DONG
YANG SHENGDONG
WANG JIANZHEN
WEN YUJUN

Assignees

浙江东江绿色石化技术创新中心有限公司

Dates

Publication Date: 20260512
Application Date: 20250512

Claims (10)

1. An efficient and energy-saving PTA wastewater treatment device, characterized by comprising: The PTA wastewater sequentially enters the plurality of evaporators to be evaporated; the waste heat recovery unit comprises a plurality of heat exchangers connected in parallel and a plurality of hot water flash tanks, and the hot water flash tanks correspondingly provide heat for the evaporators; The PTA mother liquor heat recovery unit includes a mother liquor flash tank that provides heat to a plurality of evaporators.
2. The energy efficient PTA wastewater treatment device according to claim 1, wherein the multi-effect evaporation unit comprises: a first effect evaporator; the top steam of the first-effect evaporator enters the second-effect evaporator; The top steam of the two-effect evaporator enters the three-effect evaporator; the top steam of the three-effect evaporator enters the four-effect evaporator.
3. The high-efficiency and energy-saving PTA wastewater treatment device according to claim 2, wherein PTA wastewater flows out from the bottom of the four-effect evaporator after entering from the side wall of the four-effect evaporator; Then the water enters from the side wall of the triple effect evaporator and flows out from the bottom of the triple effect evaporator; Then the water enters from the side wall of the two-effect evaporator and flows out from the bottom of the two-effect evaporator; Then enters from the side wall of the first-effect evaporator and then flows out from the bottom of the first-effect evaporator.
4. The energy efficient PTA wastewater treatment device according to claim 2 or 3, wherein a plurality of hot water flash tanks comprises: The top steam of the hot water primary flash tank flows back into the hot water primary flash tank after entering the first-effect evaporator; The top steam of the hot water secondary flash tank flows back into the hot water secondary flash tank after entering the second-effect evaporator; The top steam of the hot water three-stage flash tank flows back into the hot water three-stage flash tank after entering the triple-effect evaporator; and the top steam of the hot water four-stage flash tank flows back to the hot water four-stage flash tank after entering the four-effect evaporator.
5. The energy efficient PTA wastewater treatment device according to claim 4, wherein the plurality of parallel heat exchangers includes an oxidation reactor off-gas heat exchanger, a post-oxidation reactor off-gas heat exchanger, and a crystallizer gas phase heat exchanger.
6. The energy efficient PTA wastewater treatment device according to claim 2 or 3, wherein the PTA mother liquor heat recovery unit includes: a mother liquor first-stage flash tank, wherein the top steam enters a first-effect evaporator and then enters a PTA device recycling tank; the bottom outlet of the mother liquor primary flash tank is communicated with the side wall of the mother liquor secondary flash tank; the bottom outlet of the mother liquor second-stage flash tank is communicated with the side wall of the mother liquor third-stage flash tank; The bottom outlet of the mother liquor third-stage flash tank is communicated with the side wall of the mother liquor fourth-stage flash tank; The bottom outlet of the mother liquor four-stage flash tank is communicated with the PTA low-temperature mother liquor tank.
7. The efficient and energy-saving PTA wastewater treatment device according to claim 6, further comprising a first-effect crystallizer and a second-effect crystallizer, wherein PTA wastewater sequentially enters a plurality of evaporators for evaporation and then sequentially enters the first-effect crystallizer and the second-effect crystallizer for evaporation and crystallization.
8. The efficient and energy-saving PTA wastewater treatment device according to claim 7, wherein the top steam of the primary flash tank of the mother liquor enters the primary crystallizer before the furnace and then flows back to the primary flash tank of the mother liquor, and the top steam of the primary crystallizer before the furnace enters the secondary crystallizer before the furnace.
9. The energy efficient PTA wastewater treatment device according to claim 8, wherein the bottom of the stokehold secondary crystallizer is communicated with an alkali incinerator, and the alkali incinerator is communicated with an ash dissolving tank.
10. The high-efficiency and energy-saving PTA wastewater treatment device according to claim 2 or 3, further comprising a stripper evaporator and a stripper, wherein the PTA wastewater enters the stripper evaporator to be evaporated, then sequentially enters the three-effect evaporator, the two-effect evaporator and the one-effect evaporator to be evaporated, and the steam at the top of the stripper enters the stripper evaporator and then flows back into the stripper.

Description

Efficient and energy-saving PTA wastewater treatment device Technical Field The utility model relates to the technical field of PTA production, in particular to a high-efficiency and energy-saving PTA wastewater treatment device. Background Terephthalic Acid (PTA) is an important raw material for producing Polyester (PET) fibers and resins, and the main stream PTA sewage treatment scheme at present is a biochemical treatment method, wherein the main stream PTA sewage treatment scheme comprises a high-efficiency anaerobic treatment process and a two-stage aerobic treatment process, and the main stream PTA sewage treatment scheme comprises a pretreatment system, an anaerobic biochemical system (IC), a biogas recovery system, a two-stage aerobic biochemical treatment system, a post-treatment and discharge system, a sludge treatment system, a chemical agent and a nutrition dosing system, and is discharged after reaching standards through treatment of a sewage treatment station. The existing sewage treatment process adopts a terminal treatment and passive treatment thought, and can meet the emission requirement, but the device has large occupied area, high energy consumption and high material consumption, a large amount of sludge is generated to be treated additionally, the treated water reaches the standard to be discharged externally, the requirement of sewage emission reduction cannot be met, and the requirement of zero emission cannot be met. The invention discloses a PTA wastewater treatment device, which adopts the thought of terminal treatment and passive treatment, and has the advantages of stable continuity and low pollution emission index, but high energy consumption and material consumption in the treatment process. Disclosure of utility model The utility model overcomes the defects of high energy consumption and high material consumption of PTA wastewater treatment in the prior art, and provides a high-efficiency energy-saving PTA wastewater treatment device which can treat PTA wastewater by utilizing the waste heat recovered by a heat recovery device without consuming fresh steam, thereby greatly reducing the energy consumption of the whole device and having the advantages of low energy consumption and low material consumption. In order to solve the technical problems, the utility model adopts the following technical scheme that 1. A high-efficiency and energy-saving PTA wastewater treatment device comprises: The PTA wastewater sequentially enters the plurality of evaporators to be evaporated; the waste heat recovery unit comprises a plurality of heat exchangers connected in parallel and a plurality of hot water flash tanks, and the hot water flash tanks correspondingly provide heat for the evaporators; The PTA mother liquor heat recovery unit includes a mother liquor flash tank that provides heat to a plurality of evaporators. The utility model utilizes the multi-effect evaporator to treat PTA wastewater, and the required heat is provided by the waste heat recovery unit and the PTA mother liquor heat recovery unit, so that the PTA wastewater is treated with high efficiency and low energy consumption, and fresh steam is not required to be consumed, thereby greatly reducing the energy consumption of the whole device and having the advantages of low energy consumption and low material consumption. Preferably, the multi-effect evaporation unit includes: a first effect evaporator; the top steam of the first-effect evaporator enters the second-effect evaporator; The top steam of the two-effect evaporator enters the three-effect evaporator; the top steam of the three-effect evaporator enters the four-effect evaporator. The first-effect evaporator, the second-effect evaporator, the third-effect evaporator and the fourth-effect evaporator are sequentially communicated, and steam generated by internal evaporation provides heat required by evaporation for the next-stage evaporator, so that the energy utilization rate is improved. Preferably, the PTA wastewater flows out from the bottom of the four-effect evaporator after entering from the side wall of the four-effect evaporator; Then the water enters from the side wall of the triple effect evaporator and flows out from the bottom of the triple effect evaporator; Then the water enters from the side wall of the two-effect evaporator and flows out from the bottom of the two-effect evaporator; Then enters from the side wall of the first-effect evaporator and then flows out from the bottom of the first-effect evaporator. The flow direction of the PTA wastewater is opposite to the flow direction of steam in the first-effect evaporator, the second-effect evaporator, the third-effect evaporator and the fourth-effect evaporator, so that the evaporation efficiency of the PTA wastewater is gradually improved, the concentration of the PTA wastewater is improved, and the subsequent crystallization efficiency is conveniently improved. Preferably, the number of hot water fl