An intermittent electrically heated liquid spray evaporation method

Abstract

The application discloses an intermittent electric heating liquid spraying evaporation method, and belongs to the chemical industry field, which comprises the following steps: (1) the heat storage body is heated to the set temperature by the heating device, and the heated heat storage body is transported to the lower side of the spraying pipe of the evaporation chamber by the conveying device; the liquid sprayed by the spraying pipe falls on the heated heat storage body; (2) the liquid to be treated is sprayed downward by the spraying pipe above the evaporation chamber and falls on the heated heat storage body; (3) after the amount of the adhesion on the heat storage body reaches the set value, the heat storage body containing the adhesion is sent out by the conveying device, and the heated heat storage body is sent to the lower side of the spraying pipe of the evaporation chamber by the conveying device, and the next spraying evaporation is carried out. The application can quickly realize the evaporation, separation and purification of the mixed liquid. Meanwhile, based on the overall improvement, the application effectively solves the problems that the equipment is easy to be blocked and scaled, and can be continuously, stably and reliably operated for a long time, thereby meeting the needs of industrial treatment.

Description

TECHNICAL FIELD

[0001] The present application relates to the chemical industry field, in particular to a kind of intermittent electric heating liquid spray evaporation method.Using the present application, the solid-liquid separation in the liquid liquid to be treated can be realized, and stable and reliable operation can meet the needs of industrial application, with the prospect of large-scale production application, with very high application value. BACKGROUND

[0002] Environmental problems have become a major problem restricting China's social and economic development, and it is also a major global concern.In the wastewater treatment process, membrane concentration method is used to purify and treat wastewater.The process produces clean water while membrane concentration also produces concentrated liquid.The concentrated liquid produced by membrane concentration has been a problem that the industry is concerned about and needs to be solved urgently, especially industrial wastewater, especially high-concentration, difficult-to-degrade industrial wastewater (such as electroplating wastewater, dyeing wastewater, pharmaceutical wastewater, etc.) concentrated liquid produced in the membrane concentration process is more difficult to handle.In addition, the treatment of leachate produced by landfill of domestic waste and leachate produced by temporary storage pool of domestic waste incineration plant is also a long-term problem that has plagued the industry.

[0003] To solve the above problems, the traditional method mainly uses multi-stage steam flash evaporation, mechanical vapor recompression (MVR for short), supercritical method, etc.Although it is efficient and energy-saving, the system is prone to corrosion, blockage, scaling and other problems, which has become a constraint and bottleneck for technology development and application.

[0004] In recent years, submerged combustion technology has been applied to landfill leachate treatment and has achieved good results.Submerged combustion evaporation uses natural gas or landfill gas as raw material and provides the energy required for liquid evaporation through direct combustion, but its energy consumption is high, and there are still some un-decomposed pollutants in the evaporated condensed water that need to be further controlled and treated.

[0005] Therefore, the present application provides a new method and / or device to solve the above problems. SUMMARY

[0006] The purpose of the present application is to provide an intermittent electric heating liquid spray evaporation method to solve the above problems.The present application relates to the evaporation treatment of concentrated liquid, specifically to the evaporation of landfill leachate, wastewater membrane treatment concentrated liquid, etc.to realize the method and device of solid-liquid separation.Using the present application, the evaporation, separation and purification of mixed liquid can be quickly realized.Meanwhile, based on the overall improvement, the present application effectively solves the problem of easy blockage and scaling of the equipment, and can be continuously, stably and reliably operated for a long time to meet the needs of industrial treatment.The inventor has found that there is no existing technology to disclose the same method and / or product, and the present application has high originality and breakthrough.

[0007] In order to achieve the above object, the present application adopts the following technical solutions:

[0008] A method for intermittent electrically heated liquid spray evaporation, comprising the following steps:

[0009] (1) The heat storage body is heated to a set temperature by a heating device, and the heated heat storage body is transported to the lower side of the spray pipe of the evaporation chamber by a conveying device; the liquid sprayed by the spray pipe falls on the heated heat storage body, and the water in the liquid evaporates under the heating action of the heat storage body, and the attachments are formed on the heat storage body;

[0010] (2) The liquid to be treated is sprayed downward by the spray pipe above the evaporation chamber, and falls on the heated heat storage body; the water vapor in the evaporation chamber is condensed and collected or discharged;

[0011] (3) After the amount of attachments on the heat storage body reaches a set value, the heat storage body containing the attachments is sent out by the conveying device, and the heated heat storage body is sent to the lower side of the spray pipe of the evaporation chamber by the conveying device for the next spray evaporation;

[0012] (4) The heat storage body containing the attachments sent out is cleaned by a cleaning device, and the attachments on the heat storage body are separated from the heat storage body, and the cleaned heat storage body is returned to the heating device for heating;

[0013] (5) Steps (1) to (4) are repeated until the spray evaporation is completed.

[0014] The method is used in the treatment of liquid.

[0015] The method is used in the evaporation, solid-liquid separation and purification of liquid.

[0016] The liquid to be treated is one or more of the following: refractory industrial wastewater, landfill leachate, waste incineration leachate, oil-water mixture and saltwater mixture.

[0017] The liquid to be treated is one of the following: refractory industrial wastewater or concentrated liquid.

[0018] The liquid to be treated is a concentrated liquid generated by membrane concentration.

[0019] The heat storage body adopts a large specific surface area, high heat capacity, corrosion resistance and heat shock resistance.

[0020] In step 1, the spray pipe sprays the liquid to be treated onto the surface of the heated heat storage body in a pulse intermittent manner.

[0021] In step 1, the heat storage body is heated by the heating device to below the decomposition temperature of the organic matter in the liquid to be treated.

[0022] In step 1, the heat storage body is heated by the heating device to 150-350℃.

[0023] By controlling the temperature of the heated heat storage body, the gas discharge speed of the evaporation chamber, and the water condensation speed in the evaporation chamber, the continuous operation of the spray evaporation process is realized.

[0024] The intermittent electrically heated liquid spray evaporation device comprises a liquid inlet pipe for inputting the liquid to be treated, a spray pipe, an evaporation chamber, a condensation unit, a conveying device, a heat storage body, a cleaning device, a solid dry substance collecting device, and a heating device.

[0025] A plurality of spray heads are arranged on the spray pipe, and the spray heads are located in the evaporation chamber. The liquid inlet pipe is connected to the spray pipe, and the liquid to be treated can be sprayed in the evaporation chamber after passing through the liquid inlet pipe and the spray pipe in sequence.

[0026] The condensation unit comprises an internal condensation water collector, a condensation liquid collecting groove, a steam collecting pipe, an external condenser, and a condensation water collector. The condensation liquid collecting groove is arranged in the evaporation chamber, and the steam in the evaporation chamber can be once condensed by the internal condensation water collector. The internal condensation water collector is connected to the condensation liquid collecting groove, and the condensation water collected on the internal condensation water collector can be discharged through the condensation liquid collecting groove. The evaporation chamber is connected to the external condenser through the steam collecting pipe, and the gas in the evaporation chamber can enter the external condenser through the steam collecting pipe to be twice condensed. The condensation liquid collecting groove and the external condenser are respectively connected to the condensation water collector, and the condensation water collected by the internal condensation water collector and the condensation water collected by the external condenser can respectively enter the condensation water collector.

[0027] The conveying device is arranged below the spray pipe. The heat storage body is located on the conveying device, and the liquid sprayed by the spray pipe can be sprayed onto the heat storage body of the conveying device and form attachments on the heat storage body. The cleaning device is connected to the conveying device, and the cleaning device can clean the heat storage body on the conveying device containing attachments and separate the heat storage body from the attachments. The solid dry substance collecting device is connected to the cleaning device, and the solid dry substance collecting device can collect the attachments separated by the cleaning device. The heating device is respectively connected to the cleaning device and the conveying device, and the heat storage body from which the attachments are removed by the cleaning device can be heated by the heating device and then returned to the conveying device.

[0028] The conveying device is a mesh belt conveyor. The cleaning device is located at the output end of the mesh belt conveyor, and the cleaning device can clean the heat storage body output by the mesh belt conveyor to separate the attachments on the heat storage body from the heat storage body.

[0029] The mesh belt of the mesh belt conveyor is made of metal material.

[0030] The conveying device is a rotary table conveyor, the rotary table conveyor is located below the evaporation chamber, the heat storage bodies heated by the heating device can be conveyed to the rotary table conveyor, and the cleaning device can clean the heat storage bodies with the adhering materials adhered to the heat storage bodies on the rotary table conveyor.

[0031] The cleaning device is a vibrating screen, and the vibrating screen can separate the heat storage bodies from the adhering materials on the heat storage bodies through vibration;

[0032] Or the cleaning device is a brush cleaning device.

[0033] The vibrating screen is a linear vibrating screen.

[0034] The heating device is one or more of an electric heating device, a gas heating device.

[0035] The heating device is one or more of a tunnel type infrared heating device, a tunnel type microwave heating device, a tunnel type infrared heating device, and a tunnel type microwave heating device.

[0036] Further comprising a control system connected with the conveying device, the heating device, and the cleaning device.

[0037] Further comprising an angle adjusting device connected with the spraying pipe and capable of changing the angle of the spraying pipe.

[0038] Further comprising a liquid inlet pump arranged on the spraying pipe and capable of providing power for the liquid in the liquid inlet pipe and adjusting the spraying speed of the spraying pipe, the liquid inlet pump being connected with the control system.

[0039] Further comprising a temporary storage pool for storing the liquid to be treated, the temporary storage pool being connected with the liquid inlet pipe.

[0040] Further comprising a condensing pump arranged on the steam collecting pipe and capable of providing power for the gas flow in the steam collecting pipe, the condensing pump being connected with the control system.

[0041] In view of the foregoing problems, the present application provides an intermittent electric heating liquid spraying evaporation method, a device thereof, and an application thereof.

[0042] Chinese patent application CN201611004575.6 discloses a low-temperature spray evaporation desulfurization wastewater treatment system, whose working principle is as follows: air enters the concentrated liquid section through the air blower and flows from bottom to top in the tower. The concentrated liquid section desulfurization wastewater is lifted to the spray evaporation section by the circulating pump. In order to prevent pipeline scaling and corrosion, a polarization device is provided. The desulfurization wastewater is heated to 40-100°C by the heater during the circulation process. The heated desulfurization wastewater is atomized and sprayed by the spraying device in the spray evaporation section, and finally falls back to the concentrated liquid section. The downward atomized and sprayed desulfurization wastewater is uniformly mixed with the upward flowing air in reverse, the desulfurization wastewater evaporates and is carried by the air, and the air reaches the saturation state at this temperature. The air carrying large particle size droplets enters the high-efficiency demister, and the saturated wet air purified by the high-efficiency demister finally enters the desulfurization tower. After running for a period of time, the concentrated liquid section will continuously concentrate to produce crystallization and solid precipitation, which is discharged to the sludge treatment system for further treatment.

[0043] Chinese patent application CN201910614436.2 discloses a wastewater evaporation and concentration system and process based on low-temperature spray desulfurization, which includes the following steps: (1) desulfurization wastewater enters the evaporation tower through the buffer tank; (2) the desulfurization wastewater clear liquid in the evaporation tower clear liquid zone is heated to 40-100°C by the heat exchanger, and is uniformly sprayed to the evaporation tower spray zone by the atomizing and spraying device; (3) the desulfurization wastewater clear liquid in the spray zone falls back to the bottom of the evaporation tower under the action of gravity, and is uniformly mixed with the low-temperature saturated wet air entering from the lower part of the evaporation tower in reverse to generate heat exchange, part of the water is evaporated and carried by the air, and the low-temperature saturated wet air becomes high-temperature saturated wet air; (4) the high-temperature saturated wet air enters the air condenser and is re-cooled to low-temperature saturated wet air by the circulating cooling water, and the carried water is separated in the form of condensed water, which can be used as water for power plant desulfurization and other processes; (5) the temperature-increased circulating cooling water enters the mechanical ventilation cooling tower for forced ventilation cooling; (6) as the condensed water is continuously separated, the concentration of the desulfurization wastewater is continuously increased, and the concentrated desulfurization wastewater enters the subsequent other treatment system; (7) during the system startup stage, the air blower extracts ambient air and sends it into the lower part of the evaporation tower, and after normal operation, the air is in a closed cycle state as a water carrying carrier, and continuously changes between low-temperature saturated state and high-temperature saturated state.

[0044] Spray evaporation is a common technical means in the chemical industry for the skilled person in the art. It is commonly used in evaporative condensers, and secondarily as a means of concentrating liquids (for example, Chinese patent application CN201910614436.2). A very small number of patents relate to the concentration and crystallization of liquids (for example, Chinese patent application CN201611004575.6). As is known, when a solution is continuously heated, three stages are sequentially achieved: concentration of the solution, crystallization of the solution, and precipitation of the solid. In the prior art, precipitation of the solid is one of the main causes of fouling and blockage of the inner walls of the equipment, greatly affecting the normal use and service life of the equipment, and is something that needs to be avoided. This is also the fundamental reason why most of the existing technology using evaporation and spraying is used to produce concentrated liquids. There is no feasible solution to this technical problem in the prior art.

[0045] The present application aims to solve the problems of corrosion, blockage, and fouling that occur when concentrated liquid produced during the treatment and resource utilization of traditional industrial wastewater, especially high-concentration, difficult-to-degrade industrial wastewater (for example, electroplating, printing and dyeing, pharmaceutical wastewater, etc.), is subjected to evaporation treatment. In the present application, a heat accumulator with a large specific surface area, high heat capacity, corrosion resistance, and thermal shock resistance is used, and the heat accumulator is provided with continuous high temperature (the heating temperature is preferably 150-350°C) and the required energy. The liquid to be treated is sprayed directly onto the surface of the heated heat accumulator in a pulsed intermittent manner (with controllable frequency), the water vapor produced by evaporation is subjected to condensation treatment in a condensation unit, and an adherent is formed on the surface of the heat accumulator. Then, the heat accumulator with the adherent is output by a conveying device and cleaned by a cleaning device to separate the heat accumulator from the adherent. The separated heat accumulator is returned to the heating device for heating and then sent into the evaporation chamber for the next spray evaporation treatment. In the present application, the heated heat accumulator is used as a carrier, and the liquid to be treated does not come into contact with the bottom wall of the evaporation chamber, thereby effectively solving the problem of fouling and blockage of the inner wall of the evaporation chamber. At the same time, the present application uses concentrated liquid as the treatment object, effectively solving the problem in the chemical industry.

[0046] In the present application, by controlling the surface temperature of the heat accumulator, the steam removal and condensation rate, the evaporation system pressure, and other parameters, the evaporation process can be continuously and efficiently carried out. Preferably, the present application uses a tunnel (tunnel) type infrared (or microwave) heat accumulator to heat, which can achieve uniform, stable, and controllable temperature of the heat accumulator. At the same time, by using an internal condensation water collector and an external condenser, the gas in the evaporation chamber can be condensed, and the condensation efficiency can be improved. Through the cleaning device, the adherent on the heat accumulator can be quickly and timely stripped, effectively ensuring the heat storage of the heat accumulator and improving the heat exchange efficiency. At the same time, by controlling the heating temperature of the heat accumulator, the temperature of the surface of the heat accumulator can be controlled below the decomposition temperature of the organic matter in the industrial wastewater, effectively ensuring that the generated gas does not contain VOCs, and greatly reducing the difficulty of tail gas treatment.

[0047] The application can be used not only for treating landfill leachate, industrial wastewater, concentrated liquid produced by membrane concentration, but also for evaporation, separation and purification of mixed liquid. Further, the application can also be used for solid-liquid separation of oil-water mixture and saltwater mixture, and has a wide application prospect. The application has a clever concept, reasonable design and convenient operation, and has no problems such as scaling and clogging, can continuously, stably and reliably operate, and has a significant progress significance. BRIEF DESCRIPTION OF DRAWINGS

[0048] The application will be described by way of example and with reference to the accompanying drawings in which:

[0049] Figure 1 It is a structural schematic diagram of the intermittent electrically heated liquid spraying evaporation device.

[0050] In the figure, the marks are as follows: 1, temporary storage pool, 2, liquid inlet pipe, 3, spraying pipe, 4, evaporation chamber, 5, built-in condensing water collector, 6, cleaning device, 7, solid dry matter collecting device, 8, heating device, 9, heat accumulator, 10, external condenser, 11, condensate water collector. DETAILED DESCRIPTION

[0051] All features disclosed in this specification, or all steps of any method or process disclosed in this specification, can be combined in any combination, except combinations where at least some of the features and / or steps are mutually exclusive.

[0052] Any feature disclosed in this specification, unless stated otherwise, can be replaced by any other feature serving the same, or a similar, purpose.

[0053] The intermittent electrically heated liquid spraying evaporation device of the embodiment comprises a temporary storage pool for storing liquid to be treated, a liquid inlet pump, a liquid inlet pipe, a spraying pipe, an evaporation chamber, a condensing unit, a conveying device, a heat accumulator, a cleaning device, a solid dry matter collecting device, a heating device and a control system.

[0054] The temporary storage pool is connected with the liquid inlet pipe, and the liquid inlet pump is arranged on the liquid inlet pipe; by adjusting the flow rate of the liquid inlet pump, the flow rate of the liquid to be treated in the liquid inlet pipe can be controlled. Meanwhile, a plurality of spray heads are arranged on the spray pipe, the spray heads are located in the evaporation chamber, and the liquid inlet pipe is connected with the spray pipe. The condensing unit comprises an internal condensing water collector, a condensing liquid collecting groove, a steam collecting pipe, an external condenser, and a condensing water collector. The condensing liquid collecting groove is arranged in the evaporation chamber, the internal condensing water collector is connected with the condensing liquid collecting groove, the evaporation chamber is connected with the external condenser through the steam collecting pipe, and the condensing liquid collecting groove and the external condenser are respectively connected with the condensing water collector. The conveying device is arranged below the spray pipe, the heat storage body is located on the conveying device, the cleaning device is connected with the conveying device, the solid dry material collecting device is connected with the cleaning device, and the heating device is respectively connected with the cleaning device and the conveying device. Meanwhile, the control system is connected with the liquid inlet pump, the conveying device, the heating device, and the cleaning device.

[0055] In the device, the liquid to be treated is placed in the temporary storage pool; the liquid to be treated is sent into the spray pipe through the liquid inlet pipe and sprayed out through the spray heads on the spray pipe; the spray pipe of the embodiment is provided with micro-holes, the liquid to be treated is sprayed out in a mist form through the micro-holes on the spray pipe, and the evaporation efficiency is greatly improved; the spray heads (i.e. micro-holes) on the spray pipe are located in the evaporation chamber, so that the liquid to be treated can be sprayed in the evaporation chamber. Meanwhile, the liquid sprayed out by the spray pipe can be sprayed onto the heat storage body of the conveying device and form attachments on the heat storage body; the cleaning device can be used for cleaning the heat storage body with attachments on the conveying device and separating the heat storage body from the attachments on the heat storage body, and the solid dry material collecting device is used for collecting the attachments separated by the cleaning device; the heat storage body with the attachments removed by the cleaning device is heated by the heating device and then returned to the conveying device for the next spraying and evaporation. When the liquid sprayed out by the spray pipe contacts the heat storage body on the conveying device, evaporation and drying occur, the steam is first condensed once by the internal condensing water collector, the condensed water collected on the internal condensing water collector is then discharged through the condensing liquid collecting groove, the gas in the evaporation chamber enters the external condenser through the steam collecting pipe for secondary condensation, and then the condensed water collected by the internal condensing water collector and the condensed water collected by the external condenser can enter the condensing water collector respectively.

[0056] Further, the conveying device of the embodiment can be a mesh belt conveyor, the mesh belt of the mesh belt conveyor is made of metal material, and the cleaning device is located at the output end of the mesh belt conveyor; the cleaning device is a linear vibrating screen; and the heating device can be a motor heating device or a gas heating device. The heat storage body and the attachments on the heat storage body can be separated by vibrating the screen.

[0057] Preferably, the heating device is a tunnel type infrared heating device, a tunnel type microwave heating device, a tunnel type infrared heating device or a tunnel type microwave heating device, which is conducive to achieving temperature balance of the heat storage body and stable and controllable. The heat storage body preferably adopts a heat storage body with large specific surface area, high heat capacity, corrosion resistance and thermal shock resistance. The cleaning device preferably adopts a brush cleaning type ash cleaning and storage, which is conducive to achieving rapid and timely stripping of the adhering matter on the heat storage body, effectively ensuring heat storage of the heat storage body and improving heat exchange efficiency.

[0058] As an alternative, the conveying device of the embodiment can be a rotary table conveyor located below the evaporation chamber. The heat storage body heated by the heating device can be conveyed to the rotary table conveyor. Further, the device of the embodiment further comprises a condensation pump arranged on the steam collection pipe, the condensation pump being connected to the control system. In this structure, the condensation pump is used to provide power for the gas flow in the steam collection pipe and adjust the steam removal and condensation rate. Preferably, the embodiment further comprises an angle adjusting device connected to the spray pipe. In this structure, the angle adjusting device is used to change the angle of the spray pipe, which is conducive to achieving variable angle and intermittent controllable flow liquid distribution.

[0059] Embodiment 1

[0060] In this embodiment, the liquid to be treated is high-salt wastewater treated by membrane in the coal chemical industry, and the main components are sodium chloride, sodium sulfate and organic matter, with a total salt content of 6.8×10 4 mg / L and a TOC (total organic carbon) of 1.1×10 4 mg / L.

[0061] In this embodiment, the spraying and evaporation step of the liquid to be treated is as follows.

[0062] (1) The heat storage body is heated to 165℃ by the heating device, and the heated heat storage body is conveyed to the lower side of the spray pipe of the evaporation chamber by the conveying device. The liquid sprayed by the spray pipe falls on the heated heat storage body, and the water in the liquid evaporates under the action of the heat storage body, and the adhering matter is formed on the heat storage body. The heat storage body is arranged by two components of titanium plate with a thickness of 1-1.5 mm and positioning plate.

[0063] (2) The liquid to be treated is sprayed downward by the spray pipe above the evaporation chamber and falls on the heated heat storage body. The water vapor in the evaporation chamber is condensed and collected or discharged.

[0064] (3) After the amount of adhering matter on the heat storage body reaches the set value, the heat storage body containing the adhering matter is sent out by the conveying device, and the heated heat storage body is sent to the lower side of the spray pipe of the evaporation chamber by the conveying device for the next spraying and evaporation.

[0065] (4) The heat storage body containing the adhering matter is cleaned by the cleaning device, and the adhering matter is separated from the heat storage body. The cleaned heat storage body is returned to the heating device for heating.

[0066] (5) Steps (1) to (4) are repeated until the spray evaporation is completed. In this embodiment, a batch of treatment is performed every 4 hours.

[0067] The gas discharged from the evaporation chamber is detected after being treated by the VOC treatment device, and the index meets the corresponding emission standard.

[0068] Meanwhile, the collected adhering matter is measured, and the measurement results are as follows: sodium chloride 74.4%, sodium sulfate 25.3%, and TOC 0.3%.

[0069] Example 2

[0070] In this embodiment, the liquid to be treated is the leachate after the landfill site is closed, and the composition is shown in Table 1.

[0071] Table 1 Leachate after the landfill site is closed

[0072] Serial number Name Unit Value 1 Biochemical oxygen demand (mg / L) 7315 2 Chemical oxygen demand (mg / L) 9970 3 Total phosphorus (mg / L) 4.95 4 Total nitrogen (mg / L) 2976.25 5 Fecal coliform group (ind / L) ≥24000 6 Ammonia nitrogen (mg / L) 2562.75 7 Chloride ion (mg / L) 12488.43 8 Sulfate radical (mg / L) 238.82 9 Calcium (mg / L) 121.76 10 Magnesium (mg / L) 462.18 11 Total alkalinity (mg / L) 11251.84 12 Carbonate radical (mg / L) 1944.44 13 Bicarbonate radical (mg / L) 9307.40 14 pH value Non-dimensional 8.46 15 Nitrate radical (mg / L) 161.93 16 Suspended matter (mg / L) 720 17 Silicon dioxide (mg / L) With interference 18 Iron (mg / L) 43.14 19 Total salt content (mg / L) 31115

[0073] In step 1, the heat storage body is heated to 175°C by the heating device, and the material of the heat storage body is 2205. Meanwhile, in step 5, a batch of treatment is performed every 3 hours. The other aspects are the same as in Example 1.

[0074] The gas discharged from the evaporation chamber is detected after being treated by the VOC treatment device, and the index meets the corresponding emission standard.

[0075] The condensed liquid is detected, and the results are shown in Table 2.

[0076] Table 2 Detection results

[0077] Serial number Control pollutants Discharge concentration limit value pollutants 1 Color (dilution multiple) 25 2 Chemical oxygen demand (CODCr) (mg / L) 67 3 Biochemical oxygen demand (BOD5) (mg / L) 23 4 Suspended matter (mg / L) 16 5 Total nitrogen (mg / L) 15 6 Ammonia nitrogen (mg / L) 10 7 Total phosphorus (mg / L) 1.5 8 Fecal coliform group (ind / L) 4200 9 Total mercury (mg / L) 0.0005 10 Total cadmium (mg / L) 0.003 11 Total chromium (mg / L) 0.05 12 Hexavalent chromium (mg / L) 0.01 13 Total arsenic (mg / L) 0.05 14 Total lead (mg / L) 0.05

[0078] The measurement results show that the condensed liquid produced by the above system meets the emission limit value requirements of Table III in the Standard for Pollution Control on Domestic Waste Landfill Sites GB16889-2008.

[0079] Meanwhile, the collected adhering matter is measured, and the main components of the adhering matter are (in mass percentage): sodium chloride 60.9%, magnesium carbonate 3.4%, calcium carbonate 0.7%, sodium carbonate 32.2%, TOC 0.3%, and other 2.5%.

[0080] Example 3

[0081] In this embodiment, the liquid to be treated is the leachate DTRO concentrated liquid. The composition is shown in Table 3.

[0082] Table 3 Physico-chemical properties of the percolate

[0083] pH CDDcr mg / L BOD5 mg / L [NH3-N mg / L] SS mg / L Conductivity 6-9 ≤15000 ≤4500 ≤7000 ≤3000 ≤100000

[0084] In step 1, the heat storage body is heated to 160°C by the heating device, and the heat storage body is made of 2205 stainless steel. Meanwhile, in step 5, a batch of treatment is performed every 2.5 hours. The other conditions are the same as those in Example 1.

[0085] The gas discharged from the evaporation chamber is treated by the VOC treatment device, and then detected. The indexes meet the corresponding emission standards.

[0086] The condensed liquid is detected, and the results are as follows: COD≤1500 mg / L, BOD5≤450 mg / L, ammonia nitrogen≤300 mg / L, and conductivity≤2000 mg / L. The removal rates of COD, BOD and ammonia nitrogen all reach more than 90%.

[0087] Meanwhile, the collected deposits are measured, and the main components of the deposits are (in mass percentage): sodium chloride 85.3%, sodium sulfate 10.4%, TOC 2.3%, and other 2%.

[0088] Example 4

[0089] In this example, the liquid to be treated is medical wastewater, and the TDS and COD thereof are 56000 mg / L and 12000 mg / L, respectively. In step 1, the heat storage body is heated to 180°C by the heating device, and the heat storage body is made of titanium. Meanwhile, in step 5, a batch of treatment is performed every 1.5 hours. The other conditions are the same as those in Example 1.

[0090] The gas discharged from the evaporation chamber is treated by the VOC treatment device, and then detected. The indexes meet the corresponding emission standards.

[0091] Meanwhile, the collected deposits are measured, and the main components of the deposits are (in mass percentage): sodium chloride 71.4%, sodium sulfate 11.6%, TOC 16.5%, and other 0.5%.

[0092] Example 5

[0093] In this example, the liquid to be treated is electroplating tank waste liquid, and the total dissolved solids and COD thereof are 11.3% and 1.8%, respectively. In step 1, the heat storage body is heated to 145°C by the heating device, and the heat storage body is made of Ti-0.8Ni-0.3Mo alloy. Meanwhile, in step 5, a batch of treatment is performed every 2 hours. The other conditions are the same as those in Example 1.

[0094] The gas discharged from the evaporation chamber is treated by the VOC treatment device, and then detected. The indexes meet the corresponding emission standards.

[0095] The condensed liquid is detected, and the results are: COD≤950, ammonia nitrogen≤120, and conductivity≤2000.

[0096] Meanwhile, the collected adhering substances are detected, mainly sodium chloride and heavy metal salts such as copper, lead, nickel and organic substances, which are sent out as hazardous waste.

[0097] The present application is not limited to the foregoing specific embodiments. The present application extends to any novel one, or any new combination, of the features disclosed in this specification, and to any novel method or process steps disclosed, or any new combination thereof.

Claims

1. A method for intermittent electric heating liquid spray evaporation, characterized in that, Includes the following steps: (1) The heat storage body is heated to the set temperature by the heating device, and the heated heat storage body is transported to the bottom of the spray pipe of the evaporation chamber by the conveying device; the liquid sprayed from the spray pipe falls on the heated heat storage body, and the water in the liquid evaporates due to the heating effect of the heat storage body, and forms an adhering substance on the heat storage body. (2) The liquid to be treated is sprayed downward through the spray pipe above the evaporation chamber and falls onto the heated heat storage body; the water vapor in the evaporation chamber is collected or discharged after condensation. (3) After the amount of attached material on the heat storage body reaches the set value, the heat storage body containing the attached material is sent out through the conveying device, and the heated heat storage body is sent into the spray pipe below the evaporation chamber through the conveying device for the next spray evaporation. (4) After the heat storage body containing the attached material is cleaned by the cleaning device, the attached material on the heat storage body is separated from the heat storage body, and the cleaned heat storage body is returned to the heating device for heating. (5) Repeat steps (1) to (4) until the spray evaporation is complete; The liquid to be treated is industrial wastewater containing recalcitrant organic matter; In step (1), the spray pipe sprays the liquid to be treated onto the heated surface of the heat storage body in a pulse intermittent manner; In step (1), the heat storage body is heated by a heating device to a temperature below the decomposition temperature of the organic matter in the liquid to be treated; In step (1), the heat storage body is heated to 150°C~350°C by a heating device; The apparatus for the aforementioned method includes an inlet pipe for inputting the liquid to be treated, a spray pipe, an evaporation chamber, a condensation unit, a conveying device, a heat storage body, a cleaning device, a solid dry matter collection device, and a heating device; The spray pipe is equipped with several nozzles, which are located in the evaporation chamber. The liquid inlet pipe is connected to the spray pipe, and the liquid to be treated can be sprayed in the evaporation chamber after passing through the liquid inlet pipe and the spray pipe in sequence. The condensation unit includes a built-in condensate collector, a condensate collection channel, a steam collection pipe, an external condenser, and a condensate collector. The condensate collection channel is located in the evaporation chamber, and the steam in the evaporation chamber can be condensed once by the built-in condensate collector. The built-in condensate collector is connected to the condensate collection channel, and the condensate collected on the built-in condensate collector can be discharged through the condensate collection channel. The evaporation chamber is connected to the external condenser through the steam collection pipe, and the gas in the evaporation chamber can enter the external condenser for secondary condensation through the steam collection pipe. The condensate collection channel and the external condenser are respectively connected to the condensate collector, and the condensate collected by the built-in condensate collector and the condensate collected by the external condenser can respectively enter the condensate collector. The conveying device is located below the spray pipe, the heat storage body is located on the conveying device, and the liquid sprayed from the spray pipe can spray onto the heat storage body of the conveying device and form an adhering substance on the heat storage body. The cleaning device is connected to the conveying device and can clean the heat storage body containing the adhering substance on the conveying device and separate the heat storage body from the adhering substance on the heat storage body. The solid dry matter collection device is connected to the cleaning device and can collect the adhering substance separated by the cleaning device. The heating device is connected to the cleaning device and the conveying device respectively, and the heat storage body with the adhering substance removed by the cleaning device can be heated by the heating device and returned to the conveying device.

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