CN116573701A - Wastewater recovery treatment method and device for HPPO (high pressure polyethylene) method propylene oxide process - Google Patents
Wastewater recovery treatment method and device for HPPO (high pressure polyethylene) method propylene oxide process Download PDFInfo
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- azeotropic distillation
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- 238000000034 method Methods 0.000 title claims abstract description 59
- 239000002351 wastewater Substances 0.000 title claims abstract description 59
- GOOHAUXETOMSMM-UHFFFAOYSA-N Propylene oxide Chemical compound CC1CO1 GOOHAUXETOMSMM-UHFFFAOYSA-N 0.000 title claims abstract description 23
- 230000008569 process Effects 0.000 title claims abstract description 22
- 238000011084 recovery Methods 0.000 title claims description 15
- 239000004698 Polyethylene Substances 0.000 title description 2
- -1 polyethylene Polymers 0.000 title description 2
- 229920000573 polyethylene Polymers 0.000 title description 2
- DNIAPMSPPWPWGF-UHFFFAOYSA-N Propylene glycol Chemical compound CC(O)CO DNIAPMSPPWPWGF-UHFFFAOYSA-N 0.000 claims abstract description 219
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 claims abstract description 196
- 238000000926 separation method Methods 0.000 claims abstract description 37
- 238000010533 azeotropic distillation Methods 0.000 claims abstract description 33
- ARXJGSRGQADJSQ-UHFFFAOYSA-N 1-methoxypropan-2-ol Chemical compound COCC(C)O ARXJGSRGQADJSQ-UHFFFAOYSA-N 0.000 claims abstract description 30
- 238000005516 engineering process Methods 0.000 claims abstract description 14
- 238000004064 recycling Methods 0.000 claims abstract description 7
- HWOWEGAQDKKHDR-UHFFFAOYSA-N 4-hydroxy-6-(pyridin-3-yl)-2H-pyran-2-one Chemical compound O1C(=O)C=C(O)C=C1C1=CC=CN=C1 HWOWEGAQDKKHDR-UHFFFAOYSA-N 0.000 claims abstract 4
- 239000002151 riboflavin Substances 0.000 claims description 25
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 claims description 24
- 239000004149 tartrazine Substances 0.000 claims description 21
- 239000012071 phase Substances 0.000 claims description 16
- 239000007789 gas Substances 0.000 claims description 12
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 11
- 238000010992 reflux Methods 0.000 claims description 10
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims description 8
- 238000002360 preparation method Methods 0.000 claims description 8
- 239000007788 liquid Substances 0.000 claims description 7
- 239000002699 waste material Substances 0.000 claims description 6
- 101000723939 Mus musculus Transcription factor HIVEP3 Proteins 0.000 claims description 4
- 230000003647 oxidation Effects 0.000 claims description 4
- 238000007254 oxidation reaction Methods 0.000 claims description 4
- 239000010865 sewage Substances 0.000 claims description 4
- 239000012808 vapor phase Substances 0.000 claims description 4
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 claims description 3
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 claims description 3
- 238000005265 energy consumption Methods 0.000 abstract description 11
- 238000004519 manufacturing process Methods 0.000 abstract description 8
- 238000010168 coupling process Methods 0.000 abstract description 7
- 230000008878 coupling Effects 0.000 abstract description 6
- 238000005859 coupling reaction Methods 0.000 abstract description 6
- 238000001704 evaporation Methods 0.000 abstract description 5
- 230000008020 evaporation Effects 0.000 abstract description 4
- 238000009833 condensation Methods 0.000 abstract description 3
- 230000005494 condensation Effects 0.000 abstract description 3
- 238000004065 wastewater treatment Methods 0.000 abstract description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 abstract 1
- 239000012045 crude solution Substances 0.000 abstract 1
- 238000009776 industrial production Methods 0.000 abstract 1
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 21
- 239000000047 product Substances 0.000 description 12
- 239000006227 byproduct Substances 0.000 description 5
- 238000001816 cooling Methods 0.000 description 4
- 239000012528 membrane Substances 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 239000004229 Alkannin Substances 0.000 description 3
- 239000004230 Fast Yellow AB Substances 0.000 description 3
- 239000004235 Orange GGN Substances 0.000 description 3
- 239000004231 Riboflavin-5-Sodium Phosphate Substances 0.000 description 3
- 239000004234 Yellow 2G Substances 0.000 description 3
- 230000008901 benefit Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- DQYBDCGIPTYXML-UHFFFAOYSA-N ethoxyethane;hydrate Chemical compound O.CCOCC DQYBDCGIPTYXML-UHFFFAOYSA-N 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000004172 quinoline yellow Substances 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 239000004173 sunset yellow FCF Substances 0.000 description 3
- BFFQFGGITJXTFP-UHFFFAOYSA-N 3-methyldioxetane Chemical compound CC1COO1 BFFQFGGITJXTFP-UHFFFAOYSA-N 0.000 description 2
- LCGLNKUTAGEVQW-UHFFFAOYSA-N Dimethyl ether Chemical compound COC LCGLNKUTAGEVQW-UHFFFAOYSA-N 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000018044 dehydration Effects 0.000 description 2
- 238000006297 dehydration reaction Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 238000007670 refining Methods 0.000 description 2
- 238000003860 storage Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- HXKKHQJGJAFBHI-UHFFFAOYSA-N 1-aminopropan-2-ol Chemical compound CC(O)CN HXKKHQJGJAFBHI-UHFFFAOYSA-N 0.000 description 1
- POAOYUHQDCAZBD-UHFFFAOYSA-N 2-butoxyethanol Chemical compound CCCCOCCO POAOYUHQDCAZBD-UHFFFAOYSA-N 0.000 description 1
- 241000208125 Nicotiana Species 0.000 description 1
- 235000002637 Nicotiana tabacum Nutrition 0.000 description 1
- 239000004721 Polyphenylene oxide Substances 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000013064 chemical raw material Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000003245 coal Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 239000002537 cosmetic Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000004043 dyeing Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000003995 emulsifying agent Substances 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 238000006735 epoxidation reaction Methods 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 239000012847 fine chemical Substances 0.000 description 1
- 235000013305 food Nutrition 0.000 description 1
- 229940102253 isopropanolamine Drugs 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 238000005373 pervaporation Methods 0.000 description 1
- 239000000575 pesticide Substances 0.000 description 1
- 229920000570 polyether Polymers 0.000 description 1
- 238000007639 printing Methods 0.000 description 1
- 238000007086 side reaction Methods 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/02—Treatment of water, waste water, or sewage by heating
- C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/34—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping with one or more auxiliary substances
- B01D3/36—Azeotropic distillation
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/30—Organic compounds
- C02F2101/34—Organic compounds containing oxygen
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
- C02F2103/34—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32
- C02F2103/36—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32 from the manufacture of organic compounds
Landscapes
- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
Abstract
The invention discloses a method for recycling alcohol ether from epoxypropane wastewater by an HPPO method, which comprises the following steps: firstly, performing multi-effect evaporation on the process wastewater, enabling propylene glycol crude solution at the bottom of an evaporator to enter a vacuum rectifying tower, evaporating out from the top of the tower, and recovering a propylene glycol product after condensation. The ether-containing wastewater at the top of the evaporator passes through an ether concentration tower, enters an azeotropic distillation tower after being concentrated, the ether component at the bottom of the evaporator enters an ether separation tower, the propylene glycol monomethyl ether component at the top of the evaporator, and the propylene glycol isomonomethyl ether component at the bottom of the evaporator. The invention adopts the optimized thermal coupling technology, not only solves the problem of wastewater treatment in the HPPO production process, but also greatly reduces the energy consumption, obtains the product with higher added value, completely meets the large-scale industrial production condition, and the obtained propylene glycol methyl ether can meet the quality standard of HG/T3939-2007 industrial propylene glycol methyl ether, and the isomeric propylene glycol methyl ether can meet the related enterprise standard.
Description
Technical Field
The invention relates to a wastewater recovery method, in particular to a wastewater recovery treatment method and device for a process for preparing propylene oxide by an HPPO method.
Background
Propylene Oxide (PO) is an important basic organic chemical raw material, PO is mainly used for producing polyether, propylene glycol and isopropanolamine, and can also be used as a main raw material of a surfactant, a demulsifier and a pesticide emulsifier, and the derivative is widely applied to industries such as automobiles, buildings, foods, tobacco, cosmetics and the like, and is an important raw material of fine chemical products.
The technology for producing propylene oxide by the hydrogen peroxide direct oxidation method (HPPO method) is a novel propylene oxide production technology, has the advantages of simple process flow, high product yield, no pollution and high byproduct value, is an environment-friendly production technology, and gradually replaces the traditional propylene oxide production technology.
The HPPO technology utilizes the direct epoxidation reaction of hydrogen peroxide and propylene to produce propylene oxide, side reaction can occur in the reaction process, propylene glycol and propylene glycol methyl ether are produced, the two byproducts can be discharged from the system along with wastewater, and propylene glycol methyl ether are important chemical raw materials and have high market value, so that higher economic benefit can be obtained by recovering the two byproducts from the wastewater.
Wherein propylene glycol monomethyl ether is an excellent solvent and is widely applied to the industries of coating, printing and dyeing, electronic chemical industry and the like; and the propylene glycol monomethyl ether and the propylene glycol isomonomethyl ether are difficult to separate and purify due to the high-water-content azeotrope formed by the propylene glycol monomethyl ether and the propylene glycol isomonomethyl ether and water.
CN103342631B discloses a process for separating propylene glycol monomethyl ether aqueous solution by double-membrane coupling technology, which utilizes a pervaporation technology coupling method to improve the yield and purity of propylene glycol monomethyl ether, and finally can obtain 99.0-99.7% propylene glycol monomethyl ether solution. The method has strong practicability in small-scale production, but generates large amount of wastewater containing ether under larger production demand, and the wastewater is treated by the permeable membrane, so that the separation task is difficult to complete.
CN210855902U discloses a recovery system for propylene oxide by-products produced by HPPO method, and by means of evaporation device, propylene glycol rectifying device, propylene glycol methyl ether recovery device, methanol removing device, concentrating device, extraction and sharpness device, etc., the purity of propylene glycol monomethyl ether and propylene glycol isomonomethyl ether is up to 99.5%, and the purity of propylene glycol is up to 99.5%. The method can realize large-scale continuous production, but the whole process involves multiple times of heavy-load rectification operation, so that the energy consumption is high, and the method is uneconomical from the viewpoint of cost.
CN113135817a discloses a method for recovering ether alcohol by-product from process wastewater of propylene oxide preparation by oxidizing propylene peroxide, by introducing the wastewater into a multi-effect evaporation device, most of water and ether are distilled out; the evaporated liquid sequentially passes through a propylene glycol light component removing tower and a propylene glycol heavy component removing tower to obtain a propylene glycol product; delivering the secondary steam and the condensate into an ether concentration tower, obtaining an ether water mixture with higher concentration at the tower top, and delivering the hydrous ether into dehydration equipment to remove water; and sequentially feeding the crude ether into a refining tower and an ether separation tower to obtain propylene glycol monomethyl ether and propylene glycol isomonomethyl ether products. The technology of thermal coupling rectification, high-efficiency membrane dehydration and the like is adopted to recycle high added value components in the wastewater, so that a better effect is achieved, but the treatment mode of the ether-water mixture is that the ether-water mixture is dehydrated by utilizing a membrane component and further treated by a refining tower, an ether separation tower and the like, so that the cost is higher, and the operation requirement is high.
As is well known, the separation operation is a separation process with energy consumption, and a set of simple separation process is needed for treating process wastewater generated in the process of preparing propylene oxide by using the HPPO method, and meanwhile, a better energy recycling system is needed, so that the separation energy consumption is greatly reduced, and the technology can generate important economic benefits.
Disclosure of Invention
The invention aims to: aiming at solving the defects of large-scale continuous treatment and high energy consumption of HPPO process wastewater treatment in the prior art, the invention provides a method and a device for recycling and treating HPPO process wastewater.
In order to solve the technical problems, the invention discloses a method for recycling and treating wastewater generated in the process of preparing propylene oxide by using an HPPO method, which is characterized by comprising the following steps:
(1) Introducing the ether-containing wastewater from the propylene oxide preparation by the hydrogen peroxide oxidation method into an evaporator I E-101, allowing the light component of the evaporator I E-101 to flow into an ether-containing wastewater buffer tank V-101, and allowing the recombinant component to flow into an evaporator II E-102; the light component of the second evaporator E-102 flows into an ether-containing wastewater buffer tank V-101, and the recombinant component flows into a propylene glycol first tower T-101 for separation; the light components at the top of the propylene glycol first tower T-101 are merged into an ether-containing wastewater buffer tank V-101, and the heavy components at the bottom of the propylene glycol first tower T-102 are sent into a propylene glycol second tower for separation; condensing the top of the propylene glycol second tower T-102 to obtain a propylene glycol product, and delivering the waste liquid at the bottom of the tower to sewage treatment;
(2) The ether-containing wastewater buffer tank V-101 collects the material flows from the evaporator I E-101, the evaporator II E-102 and the propylene glycol I tower T-101, and then sends the material flows into the ether concentration tower T-103, the light components at the top of the ether concentration tower T-103 enter the azeotropic distillation tower T-104, and the heavy component wastewater is sent to sewage treatment; condensing and layering the light components at the top of the azeotropic distillation tower T-104, and refluxing the light components at the bottom of the azeotropic distillation tower T-105; propylene glycol monomethyl ether products are extracted from the top of the ether separation tower T-105, and propylene glycol iso-monomethyl ether products are extracted from the bottom of the ether separation tower T-105;
wherein, the content range of the components of the ether-containing wastewater from the preparation of propylene oxide by the propylene peroxide oxidation method is shown in the table 1:
TABLE 1
| Component (A) | Content wt% |
| Monomethyl ether | 0～5 |
| Isomomethyl ether | 0～5 |
| Methanol | 0～10 |
| Water and its preparation method | 0～95 |
| Propylene glycol | 0～10 |
| Other components | 0～3 |
The gas phase of the evaporator E-101 is used as a tower kettle reboiler heat source of the ether concentration tower T-103 and the azeotropic distillation tower T-104 according to the pinch point heat exchange technology; the vapor phase of evaporator two E-102 was used as the heat source for the bottoms reboiler of the ether separation column T-105. And the heat exchange is carried out on a plurality of hot streams and a plurality of cold streams by adopting the pinch point heat exchange, and the pinch point temperature of the system is searched through a T-H diagram so as to achieve the optimal energy recycling.
Preferably, benzene is adopted as an entrainer in the azeotropic distillation tower T-104, the gas phase is condensed and then is kept stand for layering in the entrainer separating tank V-102 at the top of the azeotropic distillation tower, the lower water phase is discharged out of the system, and the upper benzene flows back into the system for recycling.
Preferably, two-stage evaporation is adopted, the first evaporator E-101 is heated by steam, the reboiling ratio is 3.5-4.5, the second evaporator E-102 is heated by steam, and the reboiling ratio is 2.5-3.5.
In the method, the loads of the tower bottoms reboilers of the ether concentration tower, the azeotropic distillation tower and the ether separation tower are larger, meanwhile, the first gas phase and the second gas phase of the evaporator have larger heat, and according to the point-clamping heat exchange technology, the first gas phase of the evaporator is used as the heat source of the tower bottom reboilers of the ether concentration tower and the azeotropic distillation tower, and the second gas phase of the evaporator is used as the heat source of the tower bottom reboilers of the ether separation tower, so that the energy is efficiently utilized. Compared with the common rectification method, the heat energy saving rate of the method can reach 42 percent.
The propylene glycol is separated by two-stage rectification, 8-12 theoretical plates are arranged in a propylene glycol-tower T-101, the mass reflux ratio is 1.05-1.1, the feeding position is 2-4 theoretical plates, the tower top pressure is 80-90kpa, the temperature is 50-60 ℃, and the tower bottom temperature is 145-155 ℃; 15-18 theoretical plates are arranged in the propylene glycol two-tower T-102, the mass reflux ratio is 1.3-1.5, the feeding position is 6-9 theoretical plates, the tower top pressure is 85-100kpa, the temperature is 120-130 ℃, and the tower bottom temperature is 170-190 ℃.
The ether concentration tower T-103 has 25-30 theoretical plates, the mass reflux ratio is 2.2-2.5, the feeding position is 3-6 theoretical plates, the tower top pressure is 90-115kpa, the temperature is 110-120 ℃, and the tower bottom temperature is 120-130 ℃.
50-55 theoretical plates are added in the azeotropic distillation tower T-104, the feeding position is 12-16 theoretical plates, the temperature is 55-80 ℃ at the top of the tower and the normal pressure, and the temperature is 120-135 ℃ at the bottom of the tower.
68-75 theoretical plates are added in the ether separation tower T-105, the mass reflux ratio is 6-8.5, the feeding position is 32-35 theoretical plates, the negative pressure operation at the top of the tower is-50 kpa, the temperature is 95-110 ℃, and the temperature at the bottom of the tower is 110-125 ℃.
The invention further provides a wastewater recovery treatment device for the HPPO propylene oxide preparation process, which comprises an evaporator E-101, an evaporator E-102, a propylene glycol first tower T-101, a propylene glycol second tower T-102, an ether-containing wastewater buffer tank V-101, an ether concentration tower T-103, an azeotropic distillation tower T-104 and an ether separation tower V-101, wherein the evaporator E-101, the evaporator E-102, the propylene glycol first tower T-101 and the propylene glycol second tower T-102 are sequentially connected, light component outlets of the evaporator E-101, the evaporator E-102 and the propylene glycol first tower T-101 are respectively connected with an inlet of the ether-containing wastewater buffer tank V-101, and an outlet of the ether-containing wastewater buffer tank V-101 is sequentially connected with the ether concentration tower T-103, the azeotropic distillation tower T-104 and the ether separation tower V-101; the bottoms of the propylene glycol first tower T-101, the propylene glycol second tower T-102, the ether concentration tower T-103, the azeotropic distillation tower T-104 and the ether separation tower V-101 are respectively provided with a tower bottom reboiler, and the tower tops are respectively provided with a condenser; the vapor phase of the evaporator E-101 can be used as heat source of reboiler of the tower kettle of the ether concentration tower T-103 and the azeotropic distillation tower T-104.
The beneficial effects are that: the method not only treats a large amount of process wastewater generated by HPPO, but also reduces the operation cost in production by a low-energy-efficiency and high-efficiency method, and has considerable industrial application prospect.
Drawings
FIG. 1 is a process flow diagram of one embodiment of the invention, wherein T-101 is a propylene glycol first tower, T-102 is a propylene glycol second tower, T-103 is an ether concentration tower, T-104 is an azeotropic distillation tower, T-105 is an ether separation tower, V-101 is an ether-containing wastewater buffer tank, V-102 is an azeotropic agent separation tank at the top of the azeotropic distillation tower, V-103 is a propylene glycol monomethyl ether product storage tank, V-104 is a propylene glycol isomonomethyl ether product storage tank, E-101 is an evaporator I, E-102 is an evaporator II, E-103 is a propylene glycol first tower top condenser, E-104 is a propylene glycol first tower bottom reboiler, E-105 is a propylene glycol second tower top condenser, E-106 is a propylene glycol second tower bottom reboiler, E-107 is an ether concentration tower bottom reboiler, E-109 is an azeotropic distillation tower top condenser, E-110 is an azeotropic distillation tower bottom, E-111 is an ether separation tower bottom reboiler, and E-112 is an ether separation tower bottom;
fig. 2 is a process flow diagram (steam direct heating mode) without heat circulation.
Detailed Description
Where numerical ranges are shown in the following examples, references to range values are understood to be optional within the range.
In the following examples, the equipment throughput and the flow rate are each exemplified by wastewater produced by producing 33 ten thousand tons of propylene oxide per year.
Example 1
As shown in the process flow chart (figure 1), 60t/h waste liquid enters an evaporator E-101, and the ether-containing waste water comprises the following components:
TABLE 2 content of components of Ether-containing wastewater
| Component (A) | Content wt% |
| Monomethyl ether | 1.9 |
| Isomomethyl ether | 1.5 |
| Methanol | 0.2 |
| Water and its preparation method | 90.64 |
| Propylene glycol | 5 |
| Other components | 0.76 |
The operation temperature is 145 ℃, the bottom heavy component is sent to the evaporator II, and the top light component is sent to the ether-containing wastewater buffer tank V101 after heat exchange and cooling; the operation temperature of the evaporator II E-102 is 132 ℃, the propylene glycol crude component at the bottom is sent to a propylene glycol first tower T-101, and the light component at the top is sent to an ether-containing wastewater buffer tank V101; the propylene glycol crude component at the bottom of the propylene glycol first tower T-101 enters a propylene glycol second tower T-102, the operation temperature is 149 ℃, the light component at the top of the tower enters an ether-containing wastewater buffer tank, and the operation temperature is 45 ℃; the operation temperature of the system is 178 ℃, the propylene glycol product is collected after being condensed from the top of the tower, the operation temperature is 127 ℃, the purity can reach 99.93%, and the recovery rate is 95.3%. Wherein the waste water amount is 48.2t/h, and the content of organic matters such as methanol, propylene glycol monomethyl ether and the like is 0.86%.
Three light components at the top of a first evaporator, a second evaporator and a propylene glycol first tower are sent into an ether-containing wastewater buffer tank, are converged by the buffer tank and then are sent into an ether concentration tower T-103, the operation temperature of the ether concentration tower is 113 ℃ at the top of the tower, 122 ℃ at the bottom of the tower, the light components at the top of the tower are condensed and then are sent into an azeotropic distillation tower T-104, a reboiler E108 at the bottom of the tower is formed by taking a gas phase component of the first evaporator E-101 as a heat source according to a pinch point heat exchange technology, and a heavy component part returns to the first evaporator E-101 and a part of wastewater is discharged out of the system; the operation temperature of the azeotropic distillation tower T-104 is 71 ℃ at the top of the tower, 128 ℃ at the bottom of the tower, benzene and water serving as an entrainer are distilled out from the top of the tower, the entrainer is layered after condensation and standing, the entrainer returns to the tower, the water phase is directly discharged out of the system, a gas phase component of an evaporator is used as a heat source in a reboiler at the tower bottom, and the heavy component of the gas phase component enters the ether separation tower; the operation temperature of the ether separation tower is 100 ℃ at the top of the tower, 114 ℃ at the bottom of the tower, the propylene glycol monomethyl ether component is obtained at the top of the tower, the purity of the propylene glycol monomethyl ether component is 99.7%, and the recovery rate is 99.8%; the heat source of the tower kettle reboiler is provided by the second gas phase of the evaporator, so that the propylene glycol isomonomethyl ether is obtained, the purity of the propylene glycol isomonomethyl ether is 99.6%, and the recovery rate is 99.2%. The waste water quantity is 5812kg/h, and the content of organic matters such as methanol, benzene and the like is 0.809 percent.
In this example, the energy consuming device load is shown in table 3.
Table 3 load table of each energy consumption device
| Bit number | Heating (kw) | Cooling (kw) | Heat exchange between materials |
| E-101 | 26953 | / | / |
| E-102 | 5423 | / | / |
| E-103 | / | 3700 | / |
| E-104 | 3543 | / | / |
| E-105 | / | 878 | / |
| E-106 | 1224 | / | / |
| E-107 | / | 14089 | / |
| E-108 | / | / | 14063 |
| E-109 | / | 11683 | |
| E-110 | / | / | 12119 |
| E-111 | / | 1249 | |
| E-112 | / | / | 1217 |
| Totalizing | 37143 | 31841 | 27398 |
Example 2
As shown in the process flow chart (figure 2), 60t/h of waste liquid (the composition of the waste liquid is the same as that of the embodiment 1) enters an evaporator I E-101, the operation temperature is 145 ℃, the bottom heavy component is sent to an evaporator II, and the top light component is sent to an ether-containing waste water buffer tank V-101 after heat exchange and cooling; the operation temperature of the evaporator II E-102 is 132 ℃, the propylene glycol crude component at the bottom is sent to a propylene glycol first tower T-101, and the light component at the top is sent to an ether-containing wastewater buffer tank V-101; the propylene glycol crude component at the bottom of the propylene glycol first tower T-101 enters a propylene glycol second tower, the operation temperature is 149 ℃, the light component at the top of the tower enters an ether-containing wastewater buffer tank, and the operation temperature is 45 ℃; the operation temperature of the system is 178 ℃, the propylene glycol product is collected after being condensed from the top of the tower, the operation temperature is 127 ℃, the purity can reach 99.93%, and the recovery rate is 94.6%. Wherein the waste water amount is 48.6t/h, and the content of organic matters such as methanol, propylene glycol monomethyl ether and the like is 0.88%.
Three light components at the top of the first evaporator, the second evaporator and the propylene glycol first tower are sent into an ether-containing wastewater buffer tank, are converged by the buffer tank and then are sent into an ether concentration tower T-103, the operation temperature is 113 ℃ at the top of the tower, 122 ℃ at the bottom of the tower, the light components at the top of the tower are condensed and then are sent into an azeotropic distillation tower, a reboiler at the bottom of the tower takes fresh steam as a heat source, a heavy component is partially returned to the first evaporator, and a part of waste liquid is discharged out of the system; the operation temperature of the azeotropic distillation tower T-104 is 71 ℃ at the top of the tower, 128 ℃ at the bottom of the tower, benzene and water serving as an entrainer are distilled out from the top of the tower, the entrainer is layered after condensation and standing, the entrainer returns to the tower, the water phase is directly discharged out of the system, the reboiler at the tower bottom takes fresh steam as a heat source, and the heavy components of the reboiler enter the ether separation tower; the operation temperature of the ether separation tower is 100 ℃ at the top of the tower, 114 ℃ at the bottom of the tower, and the propylene glycol monomethyl ether component is obtained at the top of the tower, the purity of the propylene glycol monomethyl ether component is 99.7%, and the recovery rate is 99.6%. The heat source of the tower kettle reboiler is provided by fresh steam, so that propylene glycol isomonomethyl ether is obtained, the purity is 99.6%, the recovery rate is 5844kg/h of 98.9% wastewater, and the content of organic matters such as methanol, benzene and the like is 0.813%.
The load of each energy consumption device in this example is shown in table 4.
The energy consumption index pairs of example 1 and example 2 are shown in table 5. The result shows that the wastewater generated by HPPO can be treated in a more energy-saving mode through thermal coupling rectification, namely, the thermal coupling rectification is more energy-saving on the premise of obtaining the product with the same quality.
Table 4 load table for each energy consumption equipment
| Bit number | Heating (kw) | Cooling (kw) |
| E-101 | 26953 | / |
| E-102 | 5423 | / |
| E-103 | / | 3700 |
| E-104 | 3543 | / |
| E-105 | / | 1121 |
| E-106 | 1224 | / |
| E-107 | / | 14089 |
| E-108 | 14063 | / |
| E-109 | / | 11683 |
| E-110 | 12117 | / |
| E-111 | / | 1249 |
| E-112 | 1217 | / |
| E-113 | / | 28309 |
| E-114 | / | 5786 |
| Totalizing | 64541 | 65935 |
Table 5 energy consumption index comparison
| (Mode) | Thermal coupling rectification | Common rectification |
| Heat source dosage (kW) | 37143 | 64541 |
| Energy conversion value (standard coal kg/h) | 4563 | 7929 |
| Energy conservation Rate (%) | 42.45％ | / |
Note that: the energy calculation value is calculated according to GB/T50441-2016 petrochemical engineering design energy consumption calculation Standard.
The invention provides a method and a device for treating wastewater of propylene oxide process, and the method for realizing the technical scheme is a plurality of methods and approaches, the above description is only a preferred embodiment of the invention, and it should be noted that, for a person skilled in the art, a plurality of improvements and modifications can be made without departing from the principle of the invention, and the improvements and modifications are also considered as the protection scope of the invention. The components not explicitly described in this embodiment can be implemented by using the prior art.
Claims (8)
1. The wastewater recovery treatment method for the HPPO method propylene oxide process is characterized by comprising the following steps:
(1) Introducing the ether-containing wastewater from the propylene oxide preparation by the hydrogen peroxide oxidation method into a first evaporator (E-101), allowing the light component of the first evaporator (E-101) to flow into a buffer tank (V-101) for the ether-containing wastewater, and allowing the recombinant component to flow into a second evaporator (E-102); the light component of the second evaporator (E-102) flows into an ether-containing wastewater buffer tank (V-101), and the recombinant component flows into a propylene glycol first tower (T-101) for separation; the light components at the top of the propylene glycol first tower (T-101) are merged into an ether-containing wastewater buffer tank (V-101), and the heavy components at the bottom of the propylene glycol first tower are sent into a propylene glycol second tower (T-102) for separation; condensing the top of a propylene glycol second tower (T-102) to obtain a propylene glycol product, and delivering the waste liquid at the bottom of the tower to sewage treatment;
(2) The method comprises the steps that an ether-containing wastewater buffer tank (V-101) collects streams from an evaporator I (E-101), an evaporator II (E-102) and a propylene glycol I tower (T-101), then the streams are sent to an ether concentration tower (T-103), light components at the top of the ether concentration tower (T-103) enter an azeotropic distillation tower (T-104), and heavy component wastewater is sent to sewage treatment; condensing and layering light components at the top of an azeotropic distillation tower (T-104) and then refluxing, and sending heavy components at the bottom of the azeotropic distillation tower into an ether separation tower (T-105); propylene glycol monomethyl ether products are extracted from the top of the ether separation tower (T-105), and propylene glycol iso-monomethyl ether products are extracted from the bottom of the ether separation tower;
the gas phase of the evaporator I (E-101) is used as a tower kettle reboiler heat source of the ether concentration tower (T-103) and the azeotropic distillation tower (T-104) according to the pinch point heat exchange technology; the vapor phase of evaporator two (E-102) was used as the heat source for the bottoms reboiler of the ether separation column (T-105).
2. The method according to claim 1, wherein benzene is adopted as an entrainer in the azeotropic distillation column (T-104), the gas phase is condensed and then is placed in an entrainer separating tank (V-102) at the top of the azeotropic distillation column for layering, the lower water phase is discharged out of the system, and the upper benzene is returned into the system for recycling.
3. The method according to claim 1, wherein the first evaporator (E-101) is heated with steam and the reboiling ratio is 3.5-4.5, and the second evaporator (E-102) is heated with steam and the reboiling ratio is 2.5-3.5.
4. The method according to claim 1, wherein the propylene glycol-tower (T-101) is provided with 8-12 theoretical plates in total, the mass reflux ratio is 1.05-1.1, the feeding position is 2-4 theoretical plates, the tower top pressure is 80-90kpa, the temperature is 50-60 ℃, and the tower bottom temperature is 145-155 ℃; 15-18 theoretical plates are arranged in the propylene glycol two tower (T-102), the mass reflux ratio is 1.3-1.5, the feeding position is 6-9 theoretical plates, the tower top pressure is 85-100kpa, the temperature is 120-130 ℃, and the tower bottom temperature is 170-190 ℃.
5. The process according to claim 1, wherein the ether concentration column (T-103) has 25 to 30 theoretical plates in total, a mass reflux ratio of 2.2 to 2.5, a feed position of 3 to 6 theoretical plates, a column top pressure of 90 to 115kpa, a temperature of 110 to 120℃and a column bottom temperature of 120 to 130 ℃.
6. The process according to claim 1, wherein the azeotropic distillation column (T-104) has a total of 50 to 55 theoretical plates, the feed position is 12 to 16 theoretical plates, the column top is at normal pressure, the temperature is 55 to 80 ℃, and the column bottom temperature is 120 to 135 ℃.
7. The process according to claim 1, wherein the ether separation column (T-105) has 68 to 75 theoretical plates in total, a mass reflux ratio of 6 to 8.5, a feed position of 32 to 35 theoretical plates, a column top negative pressure operation of-50 kpa, a temperature of 95 to 110℃and a column bottom temperature of 110 to 125 ℃.
8. The wastewater recovery treatment device for the HPPO propylene oxide preparation process is characterized by comprising an evaporator I (E-101), an evaporator II (E-102), a propylene glycol first tower (T-101), a propylene glycol second tower (T-102), an ether-containing wastewater buffer tank (V-101), an ether concentration tower (T-103), an azeotropic distillation tower (T-104) and an ether separation tower (V-101), wherein the evaporator I (E-101), the evaporator II (E-102), the propylene glycol first tower (T-101) and the propylene glycol second tower (T-102) are sequentially connected, light component outlets of the evaporator I (E-101), the evaporator II (E-102) and the propylene glycol first tower (T-101) are respectively connected with an inlet of the ether-containing wastewater buffer tank (V-101), and an outlet of the ether-containing wastewater buffer tank (V-101) is sequentially connected with the ether concentration tower (T-103), the azeotropic distillation tower (T-104) and the ether separation tower (V-101); the bottoms of the propylene glycol first tower (T-101), the propylene glycol second tower (T-102), the ether concentration tower (T-103), the azeotropic distillation tower (T-104) and the ether separation tower (V-101) are respectively provided with a tower bottom reboiler, and the tower tops are respectively provided with a condenser; the vapor phase of the evaporator I (E-101) can be used as a heat source of a tower kettle reboiler of an ether concentration tower (T-103) and an azeotropic distillation tower (T-104) optionally.
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| CN117247315A (en) * | 2023-09-19 | 2023-12-19 | 江苏嘉宏新材料有限公司 | Method for removing water content from propylene oxide byproduct propylene glycol monomethyl ether |
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| CN117247315A (en) * | 2023-09-19 | 2023-12-19 | 江苏嘉宏新材料有限公司 | Method for removing water content from propylene oxide byproduct propylene glycol monomethyl ether |
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