Epoxy resin refining wastewater recycling device

Abstract

The utility model belongs to the technical field of recycling devices, and particularly relates to an epoxy resin refining wastewater recycling device. The epoxy resin refining wastewater recycling device comprises a pretreatment unit, a primary evaporation and concentration unit, a solid-liquid separation unit, a secondary concentration unit, an energy recovery unit and a product recovery unit. An evaporator of the first-stage evaporation concentration unit is communicated with an outlet of the filter, and a gas-phase outlet is connected with the condenser. And a centrifugal separator of the solid-liquid separation unit is communicated with a concentrated solution outlet of the evaporator. The secondary concentration unit comprises a falling-film evaporator and a separator, a feed port of the falling-film evaporator is connected with a liquid phase outlet of the condenser, and a steam port of the falling-film evaporator is communicated with the separator. A compressor air inlet of the energy recovery unit is connected with a separator gas phase outlet, and an air outlet is connected with a heating medium inlet of the falling film evaporator. And the product recovery unit comprises a polyethylene glycol solution storage tank. According to the epoxy resin refining wastewater recycling device provided by the utility model, the process is simplified, and the energy consumption and the operation cost are reduced.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of recycling device, concretely relates to an epoxy resin refined wastewater recycling device. BACKGROUND

[0002] Epoxy resin needs to be refined in the production process, and wastewater containing high-concentration polyethylene glycol (PEG) is generated in this stage. Polyethylene glycol is often used as a catalyst or reaction medium in the synthesis of epoxy resin and has high economic value. However, in the existing wastewater treatment process, polyethylene glycol is usually treated as a pollutant that needs to be removed.

[0003] Currently, the conventional treatment process for epoxy resin refined wastewater mainly includes: first, quality separation and flow separation and demulsification to remove oil and part of the chemical oxygen demand (COD); then, using advanced oxidation process, etc. to open the ring and break the chain of macromolecules such as polyethylene glycol and refractory organic matter, aiming to improve the biodegradability of wastewater; finally, neutralization and precipitation to adjust the pH to neutral and remove heavy metals and part of the phosphorus.

[0004] However, the above existing technology has the following problems: first, resource waste is serious and the cost is high. The core idea of the existing process is "treatment" rather than "recycling", and the polyethylene glycol with high recycling value is degraded and destroyed as a pollutant. This not only causes waste of valuable raw materials, but also makes the enterprise need to continuously invest in new polyethylene glycol, while also needs to bear the high cost of oxidizing agents and energy consumption required for degrading these organic matters, resulting in high overall operating cost. Second, the treatment process is complex and the running cost is high. The oxidation and chain breaking process itself is a unit operation with high energy consumption and high reagent consumption, and in order to facilitate subsequent biochemical treatment, supporting biochemical treatment facilities need to be built, which has long process flow, large land occupation, high investment and operation and maintenance cost. Third, it cannot fundamentally solve the problem of high COD. Although the oxidation process decomposes macromolecular PEG into small molecules and temporarily improves the biodegradability, the total organic matter content (i.e. COD value) in the wastewater does not decrease significantly, but only changes in form. The pressure of subsequent treatment is transferred to the biochemical system, the overall treatment efficiency is low, and there is a risk of incomplete treatment.

[0005] In order to solve the problem of recycling polyethylene glycol, some special recycling devices have appeared in the existing technology. For example, some devices separate and purify polyethylene glycol from salt-containing wastewater through distillation, condensation and centrifugation. Although this kind of device realizes the recycling of PEG, it usually has the problems of single process flow, limited recycling efficiency and high energy consumption. Especially for high-salt and high-COD wastewater generated by epoxy resin refining, simple distillation-centrifugation combination is difficult to realize efficient and rapid concentration and separation of PEG, and the energy cannot be effectively recycled, resulting in high operating cost. Utility Model Content

[0006] The technical problem to be solved by this utility model is to overcome the above-mentioned defects in the existing technology and provide an epoxy resin refining wastewater recycling device that can directly and efficiently recover polyethylene glycol from epoxy resin refining wastewater, realize resource recycling, and at the same time simplify the process and reduce energy consumption and operating costs.

[0007] The epoxy resin refining wastewater recycling device includes a pretreatment unit, a primary evaporation and concentration unit, a solid-liquid separation unit, a secondary concentration unit, an energy recovery unit, and a product recovery unit. The pretreatment unit includes a filter; the primary evaporation and concentration unit includes an evaporator for heating and concentrating the filtered wastewater, the evaporator being connected to the filter outlet, and the evaporator's gas phase outlet being connected to a condenser; the solid-liquid separation unit includes a centrifuge for separating solid salts and high-salt liquids from the concentrated liquid, the centrifuge being connected to the concentrated liquid outlet of the evaporator; the secondary concentration unit includes a falling film evaporator and a... The separator is used to further concentrate the low-concentration polyethylene glycol solution obtained from condensation. The inlet of the falling film evaporator is connected to the liquid phase outlet of the condenser, and the steam outlet of the falling film evaporator is connected to the separator. The energy recovery unit includes a compressor for compressing secondary steam and using it as a heat source for reuse. The inlet of the compressor is connected to the gas phase outlet of the separator, and the outlet of the separator is connected to the heating medium inlet of the falling film evaporator. The product recovery unit includes a polyethylene glycol solution storage tank for storing the concentrated polyethylene glycol solution. The polyethylene glycol solution storage tank is connected to the bottom liquid outlet of the falling film evaporator and the separator.

[0008] Preferably, it also includes a water recycling unit, including a water recycling tank, which is connected to the condensate outlet of the falling film evaporator.

[0009] Preferably, the solid-liquid separation unit further includes a brine tank and a brine pump. The inlet of the brine tank is connected to the high-salt liquid outlet of the centrifugal separator, the inlet of the brine pump is connected to the outlet of the brine tank, and the outlet of the brine pump is connected to the feed inlet of the evaporator.

[0010] Preferably, the pretreatment unit further includes a wastewater storage tank and a wastewater pump connected in sequence, wherein the wastewater storage tank, wastewater pump and filter are connected in sequence for storing and initially filtering epoxy resin refining wastewater.

[0011] Preferably, the device further includes a first vacuum assembly and a second vacuum assembly. The first vacuum assembly includes a first vacuum pump connected to the condenser to maintain the internal pressure of the evaporator at 15-25 kPa. The second vacuum assembly includes a second vacuum pump positioned above the separator to maintain the internal pressure of the secondary concentration unit at 10-20 kPa.

[0012] Preferably, an agitator is arranged inside the polyethylene glycol solution storage tank, a density monitor is arranged at the bottom of the polyethylene glycol solution storage tank for monitoring the density of the polyethylene glycol solution in real time, and the bottom of the polyethylene glycol solution storage tank is communicated with a polyethylene glycol pump, and an outlet of the polyethylene glycol pump is connected to a refining kettle for recycling the recovered condensed water for production.

[0013] Preferably, an outlet of the recycled water storage tank is communicated with a recycled water pump.

[0014] Preferably, the separator is arranged on a pipeline between a gas phase outlet of the falling film evaporator and an air inlet of the compressor for realizing secondary gas-liquid separation.

[0015] Preferably, a liquid phase outlet of the condenser is communicated with a condensed water tank, the condensed water tank is communicated with a condensed water pump, and the condensed water pump is communicated with a feed inlet of the falling film evaporator.

[0016] Compared with the prior art, the polyethylene glycol refining wastewater recycling device has the beneficial effects that:

[0017] (1) The polyethylene glycol refining wastewater recycling device realizes efficient resource recycling and cost reduction and efficiency increase, directly concentrates and purifies the polyethylene glycol catalyst in wastewater by a physical separation method and recycles the polyethylene glycol catalyst for production, changes waste into treasure, fundamentally changes the traditional waste treatment-discharge mode, and significantly reduces raw material cost and wastewater treatment cost.

[0018] (2) The polyethylene glycol refining wastewater recycling device realizes energy saving and consumption reduction by two-stage evaporation concentration and mechanical steam recompression technology, utilizes an evaporator + falling film evaporator combination to efficiently treat high-salinity wastewater, and adopts a compressor to recycle secondary steam heat energy, greatly reduces the dependence on external heat sources, simplifies the process, and has low operation energy consumption.

[0019] (3) The polyethylene glycol refining wastewater recycling device reduces pollutants from the source, directly greatly reduces the COD value of wastewater by recycling polyethylene glycol and producing reusable condensed water, reduces the load of a subsequent biochemical treatment system, solves the problem that a traditional process only converts pollutants but cannot completely remove the pollutants, and has remarkable environmental benefits. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a schematic view of the polyethylene glycol refining wastewater recycling device.

[0021] In the figure: 1, wastewater storage tank; 2, wastewater pump; 3, filter; 4, evaporator; 5, centrifugal separator; 6, brine tank; 7, brine pump; 8, condenser; 9, first vacuum pump; 10, condensate tank; 11, condensate pump; 12, falling film evaporator; 13, separator; 14, second vacuum pump; 15, compressor; 16, polyethylene glycol solution storage tank; 17, stirrer; 18, density monitor; 19, polyethylene glycol pump; 20, recycled water storage tank; 21, recycled water pump; 22, polyethylene glycol pipeline; 23, pure water pipeline. DETAILED DESCRIPTION

[0022] The utility model will be further described below in combination with specific embodiments.

[0023] The wastewater pump 2 is a screw pump; the filter 3 is a bag filter; the evaporator 4 is a forced circulation evaporator; the centrifugal separator 5 is a concentration filter centrifuge; the brine pump 7 is a screw pump; the condenser 8 is a horizontal shell and tube condenser; the first vacuum pump 9 is a variable frequency screw vacuum pump; the condensate pump 11 is a screw pump; the falling film evaporator 12 is a single-effect falling film evaporator; the separator 13 is a gravity type gas-liquid separator; the second vacuum pump 14 is a screw vacuum pump; the compressor 15 is a steam turbine compressor; and the density monitor 18 is a tuning fork densimeter.

[0024] As shown in the figure, the device for recycling epoxy resin refining wastewater comprises a pretreatment unit, a primary evaporation and concentration unit, a solid-liquid separation unit, a secondary concentration unit, an energy recovery unit and a product recovery unit. Figure 1 The pretreatment unit comprises a filter 3; the primary evaporation and concentration unit comprises an evaporator 4 for heating and concentrating the filtered wastewater, the evaporator 4 being in communication with the outlet of the filter 3, and the gas phase outlet of the evaporator 4 being connected to a condenser 8; the solid-liquid separation unit comprises a centrifugal separator 5 for separating the solid salt from the high-salt liquid in the concentrated liquid, the centrifugal separator 5 being in communication with the concentrated liquid outlet of the evaporator 4; the secondary concentration unit comprises a falling film evaporator 12 and a separator 13 for re-concentrating the low-concentration polyethylene glycol solution obtained by condensation, the feed inlet of the falling film evaporator 12 being in communication with the liquid phase outlet of the condenser 8, and the steam port of the falling film evaporator 12 being in communication with the separator 13; the energy recovery unit comprises a compressor 15 for compressing the secondary steam as a heat source for recycling, the air inlet of the compressor 15 being connected to the gas phase outlet of the separator 13, and the gas outlet of the separator 13 being connected to the heating medium inlet of the falling film evaporator 12; and the product recovery unit comprises a polyethylene glycol solution storage tank 16 for storing the concentrated polyethylene glycol solution, the polyethylene glycol solution storage tank 16 being in communication with the bottom liquid outlet of the falling film evaporator 12 and the separator 13.

[0025] The solid-liquid separation unit further comprises a brine tank 6 and a brine pump 7, the inlet of the brine tank 6 being communicated with the high-salt liquid outlet of the centrifugal separator 5, the inlet of the brine pump 7 being communicated with the outlet of the brine tank 6, and the outlet of the brine pump 7 being communicated with the feed inlet of the evaporator 4.

[0026] The pre-treatment unit further comprises a wastewater storage tank 1 and a wastewater pump 2 communicated in sequence, the wastewater storage tank 1 and the wastewater pump 2 being communicated with the filter 3 in sequence for storing and preliminarily filtering the epoxy resin refining wastewater.

[0027] The device further comprises a first vacuum assembly and a second vacuum assembly, the first vacuum assembly comprising a first vacuum pump 9 connected with the condenser 8 for maintaining the internal pressure of the evaporator 4 at 15-25 kPa, and the second vacuum assembly comprising a second vacuum pump 14 arranged above the separator 13 for maintaining the internal pressure of the secondary concentration unit at 10-20 kPa.

[0028] The polyethylene glycol solution storage tank 16 is internally provided with a stirrer 17, and a density monitor 18 is arranged at the bottom of the polyethylene glycol solution storage tank 16 for real-time monitoring of the density of the polyethylene glycol solution, the bottom of the polyethylene glycol solution storage tank 16 being communicated with a polyethylene glycol pump 19, and the outlet thereof being used for connecting to a refining kettle for recycling the condensed water for production. A polyethylene glycol pipeline 22 and a pure water pipeline 23 are arranged on the polyethylene glycol solution storage tank 16 for concentration adjustment.

[0029] The outlet of the recycled water storage tank 20 is communicated with a recycled water pump 21.

[0030] The separator 13 is arranged on the pipeline between the gas phase outlet of the falling film evaporator 12 and the gas inlet of the compressor 15 for realizing secondary separation of gas and liquid.

[0031] The liquid phase outlet of the condenser 8 is communicated with a condensed water tank 10, the condensed water tank 10 is communicated with a condensed water pump 11, and the condensed water pump 11 is communicated with the feed inlet of the falling film evaporator 12.

[0032] The low-concentration polyethylene glycol solution enters the falling film evaporator 12 and is separated into high-concentration polyethylene glycol solution and steam under the action of steam heating and negative pressure, the high-concentration polyethylene glycol solution and the steam are separated in the separator 13, and the steam is pressurized and concentrated by the compressor 15 and sent to the falling film evaporator 12 to continue to provide heat.

[0033] The working process of the epoxy resin refining wastewater recycling device is as follows:

[0034] (1) Start the wastewater pump 2 to pump the high-salt wastewater in the wastewater storage tank 1 into the filter 3, filter out impurities, and then pump into the evaporator 4 for heating and concentration;

[0035] (2) Start the first vacuum pump 9 to provide vacuum degree for the evaporator 4 and the condenser 8, accelerate the evaporation speed, the temperature of the high-salinity wastewater reaches 80-90℃ under the pressure of 15-25kPa, the first vacuum pump 9 pumps the steam generated in the evaporator 4 to the condenser 8 for condensation, and the condensed water is collected in the condensate tank 10, the operating pressure is 15-25kPa, and the temperature is kept at 80-90℃, after the evaporator 4 is concentrated to a certain extent, the material in the evaporator 4 is punched into the centrifugal separator 5, the centrifugal separator 5 separates the solid salt from other liquids, i.e. high-salinity liquid, the high-salinity liquid enters the brine tank 6, and when the liquid level reaches a certain level, the high-salinity liquid is punched into the evaporator 4 through the brine pump 7 for further concentration according to the production arrangement;

[0036] (3) The steam evaporated from the evaporator 4 is liquefied by the condenser 8 and collected in the condensate tank 10 to obtain a low-concentration polyethylene glycol solution, when the condensate tank 10 reaches the set liquid level, the condensate pump 11 is used to punch into the falling film evaporator 12, the second vacuum pump 14 is started, the system is maintained at 10-20kPa, and the temperature is controlled at 60-80℃, the compressor 15 compresses the steam as a heat source, and a high-concentration polyethylene glycol solution is obtained at the bottom of the falling film evaporator 12 or the separator 13, and when the set liquid level is reached, it is punched into the polyethylene glycol solution storage tank 16;

[0037] (4) According to the density monitor 18, the concentration of polyethylene glycol is adjusted by punching in new polyethylene glycol or pure water, the stirrer 17 is started to mix, a uniform system of polyethylene glycol solution is obtained, and then the polyethylene glycol pump 19 is used to punch into the refining kettle;

[0038] (5) In the falling film evaporator 12, the low-concentration polyethylene glycol solution is separated into a high-concentration polyethylene glycol solution and steam under the action of steam heating and negative pressure. The steam is further separated in the separator 13, and then compressed by the compressor 15 as a heat source and returned to the falling film evaporator 12. The condensed water is recycled to the recycled water storage tank 20 and used for production by the recycled water pump 21.

Claims

1. A device for recycling epoxy resin refining wastewater, characterized in that: The device comprises a pretreatment unit, a primary evaporation and concentration unit, a solid-liquid separation unit, a secondary concentration unit, an energy recovery unit, and a product recovery unit.

2. The epoxy resin fine wastewater recycling device according to claim 1, characterized by: The device further comprises a reuse water unit comprising a reuse water storage tank (20) in communication with the condensate water outlet of the falling film evaporator (12).

3. The epoxy resin fine wastewater recycling device according to claim 1, characterized by: The solid-liquid separation unit further comprises a brine tank (6) and a brine pump (7), the inlet of the brine tank (6) being in communication with the high-salt liquid outlet of the centrifugal separator (5), the inlet of the brine pump (7) being in communication with the outlet of the brine tank (6), and the outlet of the brine pump (7) being in communication with the feed inlet of the evaporator (4).

4. The epoxy resin fine wastewater recycling device according to claim 1, characterized by: The pretreatment unit further comprises a wastewater storage tank (1) and a wastewater pump (2) in sequence, which are in sequence with the filter (3).

5. The epoxy resin fine wastewater recycling device according to claim 1, characterized by: The device further comprises a first vacuum assembly and a second vacuum assembly, the first vacuum assembly comprising a first vacuum pump (9) connected with the condenser (8), and the second vacuum assembly comprising a second vacuum pump (14) connected with the separator (13).

6. The epoxy resin waste water refining recycling device according to claim 1, characterized in that: The polyethylene glycol solution storage tank (16) is internally provided with a stirrer (17), and a density monitor (18) is arranged at the bottom of the polyethylene glycol solution storage tank (16), and the bottom of the polyethylene glycol solution storage tank (16) is in communication with a polyethylene glycol pump (19).

7. The epoxy resin fine wastewater recycling device according to claim 2, characterized by: The outlet of the reuse water storage tank (20) is in communication with a reuse water pump (21).

8. The epoxy resin fine wastewater recycling device according to claim 1, characterized by: The separator (13) is arranged on the pipeline between the gas phase outlet of the falling film evaporator (12) and the air inlet of the compressor (15).

9. The epoxy resin waste water refining recycling device according to claim 1, characterized in that: The liquid phase outlet of the condenser (8) is in communication with a condensate tank (10), the condensate tank (10) is in communication with a condensate pump (11), and the condensate pump (11) is in communication with the feed inlet of the falling film evaporator (12).

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