High-concentration high-viscosity wastewater evaporation device

Abstract

The invention discloses a high-concentration and high-viscosity wastewater evaporation device which is characterized in that high-concentration and high-viscosity salt-containing wastewater raw water enters a hopper through a raw water preheater, a mother liquor circulating pump is started to enable saturated salt-containing wastewater mother liquor in the hopper to enter a mother liquor heater, and the mother liquor is heated in the mother liquor heater by steam pumped out by an evaporator in a vacuum state; the heated mother liquor circulates from an outlet of the mother liquor heater to a feed port of the evaporator; the heated mother liquor is sprayed into the evaporator through a radial nozzle on a central shaft of an auger salt scraper in the evaporator, the auger salt scraper is started to scrape off salt separated out of the evaporator, the salt falls into a hopper, and the salt in the hopper is subjected to saturation separation and is output through a discharging port of an auger salt discharging device; and in the mother liquor heater, the steam is cooled into condensed water, the condensed water flows into the raw water preheater to preheat the high-concentration high-viscosity salt-containing wastewater raw water and enters the hopper to be circulated, and the cooled condensed water is discharged into the circulating water tank for production recycling. The device has the characteristics of low treatment cost, low energy consumption, stable and reliable operation and the like.

Description

Technical Field

[0001] The invention relates to the technical field of environmental protection, energy saving and emission reduction, and in particular to a high-concentration and high-viscosity wastewater evaporation device. Background Art

[0002] At present, with the requirements of zero wastewater discharge of terminal enterprises and their own needs for energy conservation and consumption reduction, the waste liquid finally sent to the hazardous waste disposal center mostly presents: complex composition, high salt, high water content, high concentration of COD, high viscosity;

[0003] During the pretreatment process of hazardous wastewater, more chemicals are added and the initial salt content is very high, resulting in the wastewater after pretreatment becoming high-salt, high-concentration COD wastewater, which is recognized by the water treatment industry as difficult to treat. For this type of wastewater, most companies use MVR or three-effect evaporation process to dispose of hazardous wastewater.

[0004] MVR is an energy-saving evaporation technology that uses the secondary steam produced during the evaporation process as a heat source to reduce external energy requirements. During operation, the MVR system compresses the secondary steam through the steam compressor to convert electrical energy into thermal energy, increase the temperature and pressure of the steam, and convert the exhaust steam into high-quality steam as the heat source of the evaporator, realizing the effective utilization of steam latent heat, greatly reducing the energy consumption of wastewater evaporation, and realizing low-energy operation of the system.

[0005] The three-effect evaporation system adopts mixed flow evaporation. It needs to input steam from the outside during the first-effect evaporation process, and uses the secondary steam generated in the evaporation process for the rear-end heating. The steam is used three times to achieve the purpose of saving steam.

[0006] The following problems are found during the actual operation of the evaporation equipment:

[0007] (1) Although the evaporation system adopts the method of steam recycling, the energy consumption is still relatively high. The MVR evaporator is mainly driven by electricity, supplemented by a small amount of steam, and the cost of treating one ton of water is about 60 to 70 yuan.

[0008] The multi-effect (taking triple-effect evaporation as an example) evaporator is mainly driven by steam energy. There will be a certain amount of power machinery consuming electrical energy in the system. The cost of treating one ton of water is about 120 yuan.

[0009] (2) The evaporation crystallization system can effectively treat the salt in the system, but the organic matter in the system mother liquor is constantly enriched. The organic-enriched mother liquor flows back to the evaporation system for continued evaporation, which will affect the evaporation capacity of the system and cause coking and scaling of the system, shorten the maintenance cycle, and increase the maintenance cost. Summary of the invention

[0010] In order to solve the defects and shortcomings existing in the above-mentioned prior art, the purpose of the present invention is to provide a high-concentration and high-viscosity wastewater evaporation device, which is an energy-saving, full-utilization, full-recycling, zero-pollution wastewater treatment device, which performs low-temperature vacuum evaporation and cooling bidirectional parallel processes on wastewater, and thus has the characteristics of low disposal cost, low energy consumption, stable and reliable operation, etc., and has good industrial application prospects.

[0011] In order to achieve the above object, the technical solution adopted by the present invention is:

[0012] A high-concentration and high-viscosity wastewater evaporation device comprises a hopper 2, an evaporator 1 arranged on the upper part of the hopper 2, an auger salt outlet 3 arranged at the salt outlet at the bottom of the hopper 2, a raw water preheater 4 inlet enters high-concentration and high-viscosity saline wastewater raw water, the raw water preheater 4 outlet is connected to the hopper 2 inlet, the hopper 2 outlet is connected to the mother liquid inlet of the mother liquid heater 6 through a mother liquid circulation pump 5, the mother liquid outlet of the mother liquid heater 6 is connected to the evaporator feed port, the steam outlet of the evaporator 1 is connected to the steam inlet of the mother liquid heater 6 through a vacuum pump 8, and the condensate outlet of the mother liquid heater 6 is connected to the condensate inlet of the raw water preheater 4; an auger salt scraper is arranged inside the evaporator, the auger salt scraper comprises a central shaft 1-11, a radial nozzle 1-10 and a spiral dragon scraper 1-9, the central shaft 1-11 is a hollow thick-walled tube and is connected to the evaporator feed port, and the radial nozzle 1-10 and the spiral dragon scraper 1-9 are installed on the central shaft 1-11;

[0013] The high-concentration and high-viscosity saline wastewater raw water enters the hopper 2 through the raw water preheater 4, and the mother liquid circulation pump 5 is started to make the saturated saline wastewater mother liquid in the hopper 2 enter the mother liquid heater 6. After the evaporator 1 is started, it is evacuated to a vacuum by the vacuum pump 8. The steam extracted in the vacuum state heats the saturated saline wastewater mother liquid in the mother liquid heater 6 by using the latent heat of steam. The heated saturated saline wastewater mother liquid circulates from the outlet of the mother liquid heater 6 to the evaporator feed port; in the evaporator, the heated saturated saline wastewater mother liquid is evaporated by the steam. The radial nozzle 1-10 on the central axis 1-11 of the auger salt scraper in the evaporator 1 sprays into the evaporator, and the auger salt scraper is started to scrape the salt precipitated in the evaporator and drop it into the hopper 2. The salt in the hopper 2 is saturated and precipitated and output through the discharge port of the auger salt outlet 3; in the mother liquor heater 6, the steam is cooled into condensed water and flows into the raw water preheater 4 to preheat the high-concentration and high-viscosity salt-containing wastewater raw water with sensible heat and enter the hopper 2 for circulation, and the cooled condensed water is discharged into the circulating water pool for production reuse.

[0014] The evaporator 1 on the hopper 2 is assembled according to the power and evaporation capacity, and a single evaporator or multiple evaporators are configured.

[0015] A gas-liquid separator 7 is provided on the pipeline connecting the steam outlet of the evaporator 1 to the steam inlet of the mother liquid heater 6 to protect the stable operation of the vacuum pump and improve the operating efficiency of the vacuum pump.

[0016] The evaporator 1 includes an upper flange 1-1 at the feed port, an evaporator feed port and a lower flange 1-2 at the feed port. The lower flange 1-2 at the feed port is connected to a transmission device. The lower part of the transmission device is an evaporator body. An electromagnetic heater 1-12 is provided on the outside of the evaporator body. An auger scraper is provided inside the evaporator body. A thrust bearing 1-13 is provided at the lower end of the central axis 1-11 of the auger scraper. The thrust bearing 1-13 is installed on a bearing frame 1-14. The bearing frame 1-14 is welded in a flange 1-15 at the lower end of the evaporator. The upper end of the central axis 1-11 of the auger scraper extends out of the transmission device and is connected to the evaporator feed port. A pulley 1-6 is provided at the upper end of the central axis 1-11.

[0017] The transmission device includes an upper frame plate 1-4 connected to the lower flange 1-2 of the feed port, a lower frame plate 1-8 connected to the evaporator body, an upper end portion of a central shaft arranged between the upper frame plate 1-4 and the lower frame plate 1-8 and a plurality of frame pillars 1-7, two sets of mechanical seals 1-3 for sealing the upper end portion of the central shaft with the upper frame plate 1-4 and the lower frame plate 1-8, two sets of mechanical seal glands 1-5 for respectively pressing the two sets of mechanical seals 1-3, a pulley 1-6 arranged on the upper end portion of the central shaft, and a driving motor 1-16 connected to the pulley 1-6; the auger salt scraper relies on the driving motor 1-16 to drive the pulley 1-6 and then drive the central shaft 1-11 to rotate.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] Compared with the MVR system: The MVR system converts electrical energy into kinetic energy and then into thermal energy through a compressor. The system is complex, the energy efficiency conversion rate is low, and the evaporator is heated unevenly, which will cause coking and affect the continuous and normal operation of the system.

[0020] Compared with the multiple-effect evaporation system: the multiple-effect evaporation system adopts mixed flow evaporation, which makes the equipment bulky and the system complex. The mother liquor is always enriched, causing coking and scaling of the system, increasing energy consumption and maintenance costs.

[0021] 1) The present invention adopts cascade utilization of energy. The mother liquor heater uses the latent heat of steam to heat the saturated saline wastewater mother liquor. The saturated water after steam cooling is used to preheat the high-concentration and high-viscosity saline wastewater raw water. The condensed water is close to room temperature when discharged, which maximizes the utilization of energy and achieves the purpose of zero pollution, full recovery and full utilization. It is suitable for promotion and application.

[0022] 2) The evaporation device of the present invention adopts an auger salt scraper to scrape off the crystallized salt adhering to the inner wall of the evaporator at any time, and the crystallized salt is cleaned out of the evaporation system in time in combination with the auger salt remover. This avoids the evaporator from being heated unevenly and clogging the pipeline due to coking, which affects the continuous operation of the system.

[0023] 3) The evaporation device of the present invention is heated by direct electromagnetic heating, and the efficiency of electromagnetic heating is 95%, which is an efficient and energy-saving heating method;

[0024] 4) The evaporation device of the present invention adopts central axis feeding and distributes the mother liquid through multi-head radial nozzles, which has an atomization effect. Combined with the electromagnetic direct heating method, it enhances the vaporization effect, greatly reduces energy consumption, the equipment occupies a small area, and the system is relatively simple.

[0025] 5) The evaporation device of the present invention adopts vacuum and low-temperature evaporation crystallization; the operating temperature of the device does not exceed 70°C, which avoids further reaction of saline wastewater at high temperature and adhesion to the evaporator and the inner wall of the pipeline, increasing the energy consumption and operating cost of the device; BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the device of the present invention.

[0027] In the figure: evaporator 1, hopper 2, auger salt discharging device 3, raw water preheater 4, mother liquid circulation pump 5, mother liquid heater 6, gas-liquid separator 7, vacuum pump 8

[0028] Figure 2 Schematic diagram of the evaporator.

[0029] In the figure: feed inlet upper flange 1-1, feed inlet lower flange 1-2, machine seal 1-3, upper frame plate 1-4, machine seal gland 1-5, pulley 1-6, frame support 1-7, lower frame plate 1-8, spiral dragon scraper 1-9, radial nozzle 1-10, center shaft 1-11, electromagnetic heater 1-12, thrust bearing 1-13, bearing frame 1-14, evaporator lower flange 1-15, drive motor 1-16. DETAILED DESCRIPTION

[0030] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0031] like Figure 1As shown, the high-concentration and high-viscosity wastewater evaporation device of the present invention comprises an evaporator 1, a hopper 2, an auger salt outlet 3, a raw water preheater 4, a mother liquid circulation pump 5, a mother liquid heater 6, a gas-liquid separator 7, and a vacuum pump 8. The evaporator 1 is arranged on the upper part of the hopper 2, the auger salt outlet 3 is arranged at the salt outlet at the bottom of the hopper 2, the raw water of the high-concentration and high-viscosity saline wastewater enters the inlet, the outlet of the raw water preheater 4 is connected to the inlet of the hopper 2, the outlet of the hopper 2 is connected to the mother liquid inlet of the mother liquid heater 6 through the mother liquid circulation pump 5, the mother liquid outlet of the mother liquid heater 6 is connected to the evaporator feed port, the steam outlet of the evaporator 1 is connected to the steam inlet of the mother liquid heater 6 through the gas-liquid separator 7 and the vacuum pump 8, and the condensed water outlet of the mother liquid heater 6 is connected to the condensed water inlet of the raw water preheater 4.

[0032] like Figure 2 As shown, the evaporator 1 of the high-concentration and high-viscosity wastewater evaporation device of the present invention comprises an upper flange 1-1 for a feed inlet, an evaporator feed inlet and a lower flange 1-2 for a feed inlet, the lower flange 1-2 for a feed inlet is connected to a transmission device, the lower part of the transmission device is an evaporator body, an electromagnetic heater 1-12 is arranged outside the evaporator body, an auger salt scraper is arranged inside the evaporator body, the auger salt scraper comprises a central shaft 1-11, a radial nozzle 1-10 and a spiral dragon scraper 1-9, the central shaft 1-11 is a hollow thick-walled tube, and the central shaft 1-11 is provided with a radial nozzle 1-1 0 and spiral dragon scraper 1-9, the lower end of the central shaft 1-11 of the auger scraper is equipped with a thrust bearing 1-13, the thrust bearing 1-13 is installed on the bearing frame 1-14, the bearing frame 1-14 is welded in the flange 1-15 at the lower end of the evaporator, the upper end of the central shaft 1-11 of the auger scraper extends out of the lower frame plate 1-8 of the transmission device and is connected to the feed port of the evaporator, and a pulley 1-6 is installed at the upper end of the central shaft 1-11, and the auger scraper relies on the drive motor 1-16 to drive the pulley 1-6 and then drive the central shaft 1-11 to rotate.

[0033] like Figure 2 As shown, the transmission device includes an upper frame plate 1-4 connected to the lower flange 1-2 of the feed port, a lower frame plate 1-8 connected to the evaporator body, an upper end portion of the central shaft arranged between the upper frame plate 1-4 and the lower frame plate 1-8 and four frame pillars 1-7, two sets of mechanical seals 1-3 for sealing the upper end portion of the central shaft with the upper frame plate 1-4 and the lower frame plate 1-8, two sets of mechanical seal glands 1-5 for respectively pressing the two sets of mechanical seals 1-3, a pulley 1-6 arranged on the upper end portion of the central shaft, and a driving motor 1-16 connected to the pulley 1-6. The auger salt scraper relies on the driving motor 1-16 to drive the pulley 1-6 and then drive the central shaft 1-11 to rotate.

[0034] The evaporator 1 of the present invention is provided with an auger salt scraper to prevent coking. The auger salt scraper has a spiral auger scraper, which can scrape off the crystallized salt at any time during the working process to avoid coking on the inner wall of the equipment and pipeline, which affects the normal operation of the equipment.

[0035] The central axis of the auger salt scraper of the present invention is a hollow thick-walled tube, which is provided with radial nozzles; during operation, wastewater is evenly sprinkled onto the inner wall of the evaporator as the central axis rotates, so that the feed distribution is more uniform, the heating is faster, and the heating efficiency is higher;

[0036] The evaporator 1 on the hopper 2 of the present invention is assembled according to the power and evaporation capacity, and can be configured with a single evaporator or multiple evaporators.

[0037] The lower part of the hopper 2 of the present invention is connected with an auger salt discharging device 3, which ensures the continuity of the process and makes the production faster and more efficient.

[0038] The working process of the device of the present invention is as follows: high-concentration and high-viscosity saline wastewater raw water enters the hopper 2 through the raw water preheater 4, the vacuum pump 8 is started to pump the pressure in the evaporator 1 to -0.75MPa, the mother liquid circulation pump 5 is started to make the saturated saline wastewater mother liquid in the hopper 2 enter the mother liquid heater 6, the evaporator 1 is evacuated to vacuum by the vacuum pump 8 after startup, the 65°C steam extracted under vacuum state heats the saturated saline wastewater mother liquid in the mother liquid heater 6 by using the latent heat of steam, and the heated saturated saline wastewater mother liquid is discharged from the mother liquid heater 6 The saturated salt-containing wastewater mother liquor is circulated to the evaporator feed port; in the evaporator, the heated saturated salt-containing wastewater mother liquor is sprayed into the evaporator through the radial nozzle 1-10 on the central axis 1-11 of the auger scraper in the evaporator 1, and the electromagnetic heater 1-12 of the evaporator and the driving motor 1-16 of the transmission device are started at the same time, and the driving motor of the auger scraper is started, and then the auger scraper is started, and the auger scraper scrapes the salt precipitated in the evaporator body and falls into the hopper 2. The salt in the hopper 2 is saturated and precipitated and output through the discharge port of the auger salt outlet 3. In the mother liquor heater 6, the condensed water after the 65℃ steam is cooled to 60℃ flows to the raw water preheater 4, and the high-concentration and high-viscosity salt-containing wastewater raw water is preheated to 50℃ by sensible heat and enters the hopper 2 for circulation, which maximizes the use of heat. The cooled 30℃ condensed water is discharged into the circulating water pool for production reuse.

Claims

1. A high-concentration and high-viscosity wastewater evaporation device, characterized in that: The invention comprises a hopper (2), an evaporator (1) arranged on the upper part of the hopper (2), an auger salt outlet (3) arranged at the salt outlet of the bottom of the hopper (2), a raw water preheater (4) inlet entering high-concentration and high-viscosity saline wastewater raw water, the raw water preheater (4) outlet connected to the hopper (2) inlet, the hopper (2) outlet connected to the mother liquid inlet of the mother liquid heater (6) through a mother liquid circulation pump (5), the mother liquid outlet of the mother liquid heater (6) connected to the evaporator feed port, and the steam outlet of the evaporator (1) connected to the mother liquid inlet of the mother liquid heater (6) through a vacuum pump (5). The pump (8) is connected to the steam inlet of the mother liquid heater (6), and the condensate outlet of the mother liquid heater (6) is connected to the condensate inlet of the raw water preheater (4); an auger salt scraper is arranged inside the evaporator, and the auger salt scraper comprises a central axis (1-11), radial nozzles (1-10) and a spiral dragon scraper (1-9); the central axis (1-11) is a hollow thick-walled tube and is connected to the evaporator feed port, and the radial nozzles (1-10) and the spiral dragon scraper (1-9) are installed on the central axis (1-11); High-concentration and high-viscosity saline wastewater raw water enters the hopper (2) through the raw water preheater (4), and the mother liquor circulation pump (5) is started to allow the saturated saline wastewater mother liquor in the hopper (2) to enter the mother liquor heater (6). After the evaporator (1) is started, it is evacuated to a vacuum state by the vacuum pump (8). The steam extracted under the vacuum state heats the saturated saline wastewater mother liquor in the mother liquor heater (6) by using the latent heat of steam. The heated saturated saline wastewater mother liquor is circulated from the outlet of the mother liquor heater (6) to the feed port of the evaporator. In the evaporator, the heated saturated saline wastewater mother liquor is evacuated by the steam. The radial nozzles (1-10) on the central axis (1-11) of the auger salt scraper in the evaporator (1) are sprayed into the evaporator, and the auger salt scraper is started to scrape the salt precipitated in the evaporator and drop it into the hopper (2). The salt in the hopper (2) is saturated and precipitated and output through the outlet of the auger salt outlet (3); in the mother liquid heater (6), the steam is cooled to condensed water and flows to the raw water preheater (4) to preheat the high-concentration and high-viscosity salt-containing wastewater raw water with sensible heat and enter the hopper (2) for circulation. The cooled condensed water is discharged into the circulating water pool for production reuse.

2. A high-concentration and high-viscosity wastewater evaporation device according to claim 1, characterized in that: The evaporator (1) on the hopper (2) is assembled according to the power and evaporation capacity, and a single evaporator or multiple evaporators are configured.

3. A high-concentration and high-viscosity wastewater evaporation device according to claim 1, characterized in that: A gas-liquid separator (7) is provided on the pipeline connecting the steam outlet of the evaporator (1) to the steam inlet of the mother liquid heater (6).

4. A high-concentration and high-viscosity wastewater evaporation device according to claim 1, characterized in that: The evaporator (1) comprises an upper flange (1-1) of a feed inlet, an evaporator feed inlet and a lower flange (1-2) of the feed inlet, the lower flange (1-2) of the feed inlet being connected to a transmission device, the lower part of the transmission device being an evaporator body, an electromagnetic heater (1-12) being arranged outside the evaporator body, an auger salt scraper being arranged inside the evaporator body, a thrust bearing (1-13) being arranged at the lower end of a central axis (1-11) of the auger salt scraper, the thrust bearing (1-13) being mounted on a bearing frame (1-14), the bearing frame (1-14) being welded in a flange (1-15) at the lower end of the evaporator, the upper end of the central axis (1-11) of the auger salt scraper extending out of the transmission device and connected to the evaporator feed inlet, and a pulley (1-6) being arranged at the upper end of the central axis (1-11).

5. A high-concentration and high-viscosity wastewater evaporation device according to claim 4, characterized in that: The transmission device comprises an upper frame plate (1-4) connected to a lower flange (1-2) of a feed port, a lower frame plate (1-8) connected to an evaporator body, an upper end portion of a central shaft arranged between the upper frame plate (1-4) and the lower frame plate (1-8) and a plurality of frame pillars (1-7), two sets of machine seals (1-3) for sealing the upper end portion of the central shaft with the upper frame plate (1-4) and the lower frame plate (1-8), two sets of machine seal glands (1-5) for respectively pressing the two sets of machine seals (1-3), a pulley (1-6) arranged on the upper end portion of the central shaft, and a driving motor (1-16) connected to the pulley (1-6); the auger salt scraper drives the pulley (1-6) by means of the driving motor (1-16) to drive the central shaft (1-11) to rotate.

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