CN103769412A - Organic polluted soil thermal desorption system capable of not generating secondary pollution to environment - Google Patents

Abstract

The invention relates to a thermal desorption system for organic polluted soil that does not cause secondary pollution to the environment, including a reverse thermal desorption device, a first-stage dust collector connected in sequence, a secondary combustion chamber, a condensation deacidification device, and a flue gas absorption device , gas-liquid separator, second-stage dust collector, smoke and dust adsorption device with condenser, and central computer control unit. Connect the water inlet of the condensation deacidification device, the mud outlet to the drying pool; the outlet of the gas-liquid separator to the water inlet of the flue gas absorption device; The cooling water inlet and exhaust port of the device are connected to the atmosphere; the discharge port of the reverse thermal desorption device, the solid dust outlet of the first and second stage dust collectors, and the drying mud outlet of the drying pool are connected to the non-burning brick machine; the non-burning brick machine, dosing Pool, organic wastewater treatment device and central computer control unit.

Description

Thermal desorption system for organic polluted soil without secondary pollution to the environment

technical field

The invention relates to the field of remediation of organic polluted soil, in particular to a thermal desorption system for organic polluted soil that does not cause secondary pollution to the environment.

Background technique

With the development of society, technology and economy, people's living standards and health levels are constantly improving, which puts forward higher requirements for the realization of a green environment, and the control of environmental pollution has become an important issue in urban construction. At present, due to the influence of high-pollution enterprises such as steel, chemical industry, and pesticides, a large amount of high-pollution risk soil remains. The danger is that the organic matter in these soils will pollute the surrounding air and water, and bring harm to human life and health. Therefore, the remediation and treatment of organic polluted soil has become an important content of environmental protection. Thermal desorption technology is a kind of organic contaminated soil remediation technology commonly used at present. Its principle is to heat the soil through direct or indirect heat exchange to decompose the pollutants in the soil or convert them into gas phase and desorb them from the soil surface or pores. , and then process the desorbed organic matter through incineration, adsorption or chemical reaction.

The existing thermal desorption system for organic polluted soil mainly includes a reverse thermal desorption device for treating organic polluted soil and its flue gas outlet is connected in sequence through the flue gas pipeline to the first-stage dust collector, the second combustion chamber, the condensation deacidification device, Flue gas absorption device, gas-liquid separator, second-stage dust collector, smoke dust adsorption device with condenser and central computer control unit that controls the operation of the entire system. In actual operation, the contaminated soil is sent to the reverse thermal desorption device through the transmission device. The hot air is in reverse contact with the soil, and the organic pollutants contained in it are heated to make them volatilize. After thermal desorption, the solid particles separated by dust removal, that is, the repaired soil, pass through the conveying device through the discharge port of the reverse thermal desorption device. The output is used as backfill; the flue gas is passed into the first-stage dust collector, and after dust removal, the flue gas is sent to the second combustion chamber, and after heating, the flue gas is sent to the flue gas treatment system, and then passes through the condensation deacidification device and the flue gas absorption device , Gas-liquid separator, second-stage dust collector and dust adsorption device with condenser. The purified and up-to-standard gas drawn out by the soot adsorption device with condenser through the induced draft fan is discharged into the atmosphere through the chimney.

The main technical defect of the existing organic polluted soil thermal desorption system is: the waste water produced after the flue gas purification and the solid dust after the dust removal by the first-stage dust collector and the second-stage dust collector are not treated, and then enter the surrounding area. environment, resulting in secondary pollution. In addition, the whole system operates in an open environment, so gas and solid dust generated by system leakage during excavation of soil and system operation will also pollute the surrounding environment.

Contents of the invention

The main purpose of the present invention is to address the above problems, to provide a thermal desorption system for organic polluted soil that does not cause secondary pollution to the environment, and to realize the purification of waste water generated after flue gas purification while repairing polluted soil and the waste water that passes through the flue gas treatment system. The solid dust after dedusting is also processed to avoid secondary pollution to the environment.

The technical solution adopted by the present invention to solve its technical problems is:

A thermal desorption system for organic polluted soil that does not cause secondary pollution to the environment, including a reverse thermal desorption device for treating organic polluted soil and a first-stage dust collector, a secondary combustion gas outlet connected in sequence through a flue gas pipeline. room, condensation deacidification device, flue gas absorption device, gas-liquid separator, second-stage dust collector, smoke and dust adsorption device with condenser, and a central computer control unit for controlling the operation of the entire system, which is characterized in that the condensation deacidification device The wastewater outlet is connected to the water inlet of an organic wastewater treatment device through a dosing tank, the water outlet of the organic wastewater treatment device is connected to the cooling water inlet of the condensation deacidification device, and the mud outlet of the organic wastewater treatment device is connected to a drying The mud inlet of the pool; the water outlet of the gas-liquid separator is connected to the water inlet of the flue gas absorption device; the waste water outlet of the dust absorption device with a condenser is connected to the waste water inlet of the dosing pool, its The cooling water outlet is connected to the cooling water inlet of the condensing deacidification device, and its exhaust port is connected to the atmosphere to discharge standard flue gas; the discharge port of the reverse thermal desorption device, the first-stage dust collector and the second-stage dust collector The solid dust outlet of the drying tank and the drying mud outlet of the drying tank are all connected to the feed port of a burn-free brick machine; the control ports of the burn-free brick machine, the dosing tank and the organic wastewater treatment device are respectively connected to the central computer control unit .

The system is set up in an air-supported greenhouse.

A greenhouse smoke and dust adsorption device for absorbing space gas in the greenhouse is provided outside the air-supported greenhouse.

The beneficial effects of the present invention are: the organic polluted soil thermal desorption system provided by the present invention solves the treatment of solid dust and waste liquid generated in the follow-up flue gas purification treatment while completing the remediation of organic polluted soil. The remediation of the soil, including the solid particles and solid dust produced in the reverse thermal desorption device and the subsequent flue gas purification treatment, and the dried mud obtained after the treatment of organic wastewater, are all treated as resources by a non-burning brick machine. After the flue gas is purified Discharge up to the standard, and recycle the waste water that has been treated by the organic waste water treatment device to remove organic matter after purification. In particular, the entire system is set in an air-supported greenhouse, and a greenhouse smoke and dust adsorption device is installed outside the shed to absorb the space gas in the shed, so that during the process of excavating the soil for treatment, the generation of dust containing pollutants and smoke from system leakage can be effectively avoided. Secondary pollution of the environment by gas and solid dust to achieve the purpose of environmental protection.

Description of drawings

Fig. 1 is a system structure block diagram of the present invention.

In the figure: 1 air bearing greenhouse, 2 feeding belt conveyor, 3 discharging belt conveyor, 4 reverse thermal desorption device, 5 first stage dust collector, 6 secondary combustion chamber, 7 condensing deacidification device, 8 Smoke absorption device, 9 gas-liquid separator, 10 second-stage dust collector, 11 smoke and dust adsorption device with condenser, 12 dosing tank, 13 organic wastewater treatment device, 14 drying tank, 15 burn-free brick machine, 16 central computer Control unit, 17 greenhouse smoke and dust adsorption device, 18-19 induced draft fan.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings and embodiments.

Figure 1 shows a thermal desorption system for organic polluted soil that does not cause secondary pollution to the environment, including a reverse thermal desorption device 4 for treating organic polluted soil and the first stage in which the flue gas outlet is sequentially connected through a flue gas pipeline Dust collector 5, secondary combustion chamber 6 for high-temperature treatment of flue gas, condensation deacidification device 7, flue gas absorption device 8, gas-liquid separator 9, second-stage dust collector 10, dust adsorption device with condenser 11 and the entire control system The operation of the central computer control unit 16 . The present invention is characterized in that the wastewater outlet of the condensation deacidification device 7 is connected to the water inlet of an organic wastewater treatment device 13 through a dosing pool 12, and the water outlet of the organic wastewater treatment device 13 is connected to the condensation deacidification device 7 The cooling water inlet of the cooling water inlet and the mud outlet of the organic wastewater treatment device are connected to the mud inlet of a drying tank 14; the water outlet of the gas-liquid separator 9 is connected to the water inlet of the flue gas absorption device 8; The waste water outlet of the soot adsorption device 11 of the device is connected to the waste water inlet of the dosing pool 12, and its cooling water outlet is connected to the cooling water inlet of the condensation deacidification device 7, and its exhaust port is connected to the atmosphere through the induced draft fan 18 to discharge Up to the standard flue gas; the discharge port of the reverse thermal desorption device 4, the solid dust outlet of the first-stage dust collector 5 and the second-stage dust collector 10, and the drying mud outlet of the drying pool 14 are all connected to a non-burning brick machine 15; the control ports of the burn-free brick machine 15, the dosing pool 12 and the organic wastewater treatment device 13 are respectively connected to the central computer control unit 16.

As shown in Figure 1, in actual implementation, the organic polluted soil is connected to the feed port of the reverse thermal desorption device 4 through the feed belt conveyor 2, and the discharge port of the reverse thermal desorption device passes through the discharge belt conveyor 3 is connected to the unburned brick machine 15, the flue gas outlet of the reverse thermal desorption device 4 is connected to the flue gas inlet of the first-stage dust collector 5, and the flue gas outlet of the first-stage dust collector 5 is connected to the flue gas of the second combustion chamber 6 The inlet is connected, the flue gas outlet of the second combustion chamber is connected with the flue gas inlet of the condensation deacidification device 7, the flue gas outlet of the condensation deacidification device is connected with the flue gas inlet of the flue gas absorption device 8, and the flue gas outlet of the flue gas absorption device It is connected to the flue gas inlet of the gas-liquid separator 9, and the flue gas outlet of the gas-liquid separator 9 is connected to the flue gas inlet of the second-stage dust collector 10, and the flue gas outlet of the second-stage dust collector is connected to the dust adsorption device with condenser The flue gas inlet of 11 is connected, and the flue gas outlet of the soot adsorption device 11 with condenser enters the chimney through the induced draft fan 18 and is discharged into the atmosphere.

Both the waste water outlet of the condensation deacidification device 7 and the waste water outlet of the soot adsorption device 11 with a condenser are connected to the water inlet of the dosing pool 12 , and the water outlet of the dosing pool 12 is connected to the organic waste water treatment device 13 .

The discharge belt conveyor 3 sends the repaired soil from the reverse thermal desorption device 4, the first-stage dust collector 5, the second-stage dust collector 10 and the drying pool 14 to the feed port of the burn-free brick machine 15 . The above-mentioned feeding belt conveyor 2, discharging belt conveyor 3, reverse thermal desorption device 4, secondary combustion chamber 6, condensation deacidification device 7, flue gas absorption device 8, second stage dust collector 10, with condensation The device smoke and dust adsorption device 11, the dosing pool 12, the organic waste water treatment device 13, and the control port of the unburned brick machine 15 are all connected with the central computer control unit 16. During the operation of the system, the central computer control unit 16 monitors the operation of the above-mentioned devices, so as to realize the precise control and adjustment of each process parameter.

Another feature of the present invention is that the above-mentioned organic polluted soil thermal desorption system is set in the air-supported greenhouse 1 . A greenhouse smoke and dust adsorption device 17 is also provided outside the air-supported greenhouse to absorb the space gas in the greenhouse. It can be seen from FIG. 1 that the entire set of equipment in the system and the restoration site are covered by the air bearing greenhouse 1 . The greenhouse smoke and dust adsorption device 17 installed outside the greenhouse communicates with the gas in the space in the air-bearing greenhouse through the induced draft fan 19 and discharges the treated flue gas that reaches the standard into the atmosphere.

In this embodiment, the above-mentioned reverse thermal desorption device 4 adopts a commercially available reverse thermal desorption device with a model of HGTΦ1.6×10.5m, which is a drum heating structure and uses diesel as fuel. It is a device that sends high-temperature gas into the rotating drum through a diesel burner to heat the material.

The burn-free brick machine 15 adopts the burn-free brick machine of the commercially available model YXQ3-15. The equipment presses the repaired soil into solid bricks through the hydraulic forming process, and does not need to be fired during the brick making process, which has no pollution to the environment.

The second combustion chamber 6 adopts the RTO-800 commercially available exhaust gas incinerator, and the harmful components in the flue gas discharged from the reverse thermal desorption device are incinerated through the high-temperature airflow generated by the combustion. The incineration temperature of the second combustion chamber is 800-1200°C. Effectively avoid the formation of dioxins.

Condensation deacidification device 7 adopts commercially available conventional equipment such as a vertical quenching tower. In the device, the flue gas is cooled and deacidified by spraying condensed water. The device is equipped with a spiral nozzle. The nozzle, under the action of the spiral nozzle, breaks the cooling water into a mist state, increases the reaction area, dissolves the acid gas in the water, and accelerates the cooling speed.

The flue gas absorption device 8 uses a commercially available WFJ-2-4 exhaust gas purification tower, which neutralizes the acidic and harmful components in the flue gas by spraying alkaline absorption liquid, and further performs acid removal treatment after the condensation deacidification device to achieve purification. purpose of smoke.

The gas-liquid separator 9 adopts a commercially available KD type vertical blade mist eliminator, which is installed after the flue gas absorption device to remove tiny water droplets entrained by the flue gas during the operation of the device to avoid damage to the downstream affect the operation of the equipment. The vane type demister is mainly equipped with a wave-shaped blade group. The mist-like flue gas collides with the wave-shaped blades and is accumulated into droplets. The corrugated blades are separated on the surface. The multi-folding structure of the corrugated blades of the mist eliminator increases the chance of mist being captured, and the unremoved mist is captured through the same action at the next turning. This repeated action greatly improves the mist removal efficiency. The separated condensed water is returned to the flue gas absorption device 8 for recycling. The flue gas continues to enter the second stage dust collector 10.

The dust adsorption device with condenser 11 adopts the commercially available activated carbon adsorption device model SXF-50, which uses activated carbon fiber as the adsorption material. The high-temperature steam inlet sprays high-temperature steam into the bottom of the device, evaporates the organic solvent adsorbed in the activated carbon, and then sends it to the built-in condenser, where cooling water is passed into the condenser to send the condensed waste water to the dosing pool for follow-up Purification, the remaining cooling water is sent to the condensation deacidification device for recycling.

The dosing pool 12 is a conventional mixing equipment. In the present embodiment, a paddle-type dosing pool is adopted. The paddle-type agitator can adjust the rotating speed, and the mixing effect is good. The acidic wastewater in the pool undergoes a neutralization reaction to achieve the purpose of neutralizing the pH value. After the reaction is completed, the neutralized wastewater is sent to the organic wastewater treatment device for subsequent treatment.

The organic wastewater treatment device 13 adopts the applicant's prior patent ZL201020567397.X "Composite Biofilm Integrated Reactor for Domestic Sewage Treatment". This patent is based on the dynamic biofilm fixation technology of the suspension carrier. Upflow biological contact oxidation filter, vertical flow sedimentation tank and downflow biological aerated filter, the bottom of the upflow biological contact oxidation filter is equipped with adjustable intermittent aeration device, ring water distribution pipe, overflow pipe, suspension Filled bed; the vertical flow sedimentation tank is equipped with a central drain pipe, a mud discharge pipe, and the central drain pipe is connected to the overflow pipe; A backwash aeration device is installed under the material bed. During work, synchronous denitrification and phosphorus removal is realized by starting the operation of the upflow biological contact oxidation filter, the operation of the vertical flow sedimentation tank, the intermittent aeration of the upflow biological contact oxidation filter, and the operation of the downflow biological aerated filter And the efficiency is high, which can effectively remove COD, ammonia nitrogen, total nitrogen and total phosphorus in the waste liquid.

The first-stage dust collector 5 adopts a commercially available CLT cyclone dust collector.

The second-stage dust collector 10 adopts a commercially available pulse bag dust collector model DMC192. The pulse bag filter is a dry dust filter device. It is suitable for capturing fine, dry, non-fibrous dust. The filter bag is made of textile filter cloth or non-woven felt, and uses the filter function of the fiber fabric to filter the dusty gas, so that the dust is blocked and the flue gas is purified. And through the control system to automatically clean the dust, the dust accumulated on the surface of the filter bag will fall off, and the filter bag will be regenerated. The cleaned dust falls into the ash hopper and is discharged through the ash discharge valve. The filtered flue gas enters the dust adsorption device 11 with a condenser, and the filtered solid dust is sent to the burn-free brick machine through the solid dust outlet to complete resource utilization.

The air bearing greenhouse 1 adopted a commercially available air bearing greenhouse. The equipment is a circular air shed formed by using an air pressure 0.2%-0.3% higher than atmospheric pressure. The interior is equipped with pillars and skeletons to form a circular space. The service life of the shed film is about 5 years, and it can be recycled and reused.

Outside the air-supported greenhouse, there is also a greenhouse smoke and dust adsorption device 17 for absorbing space gas in the greenhouse. Due to the relatively low smoke and dust concentration in the space in the shed, the smoke and dust adsorption device 17 in the greenhouse adopts a commercially available model SXF-25 activated carbon adsorption device without a condenser. , Effectively avoid the generated dust containing pollutants, gas and solid dust from system leakage to the outside world to form secondary pollution to the surrounding environment, and achieve the purpose of environmental protection.

Working process and principle of the present invention are as follows:

As shown in Figure 1, under the control of the central computer control unit 16, the system completes the following processing process: After the polluted soil is crushed, it is sent to the reverse thermal desorption device 4 through the feeding belt conveyor 2, and the thermal desorption The temperature is 450-650°C, and the treatment time is 20-35 minutes. In the device, the hot air is in reverse contact with the soil, and the organic pollutants contained in it are heated to volatilize them, and the solid particles separated after thermal desorption, that is, the repaired soil, are discharged from the reverse thermal desorption device The outlet is sent to the burn-free brick machine 15 through the discharge belt conveyor 3 for resource disposal. The flue gas containing a large amount of solid dust produced after thermal desorption is passed into the first-stage dust collector 5, that is, the cyclone dust collector, and the solid dust separated by dust removal is also sent to the burn-free brick machine 15 for resource disposal. The flue gas after dedusting is sent to the secondary combustion chamber 6, heated to 800-1200°C, and the harmful components in the exhaust gas are incinerated by the high-temperature gas of combustion, and then sent to each equipment of the flue gas treatment system for purification, including: condensation deacidification Device 7, flue gas absorption device 8, gas-liquid separator 9, second-stage dust collector 10, and condensed smoke dust adsorption device 11, the purified gas is discharged through the chimney. In the condensation deacidification device 7, the flue gas is cooled and the acid gas is dissolved in water for deacidification and purification. The separated wastewater is sent to the dosing pool 13 for subsequent purification. The flue gas continues to enter the flue gas absorption device 8, that is, the waste gas purification tower, and further neutralizes the acidic and harmful components in the flue gas by the sprayed alkaline absorption liquid to achieve the purpose of further acid removal and purification. Due to the small particle size water droplets entrained in the flue gas, in order to avoid affecting the operation of downstream equipment. Then enter the gas-liquid separator 9, that is, the vane demister, to separate the droplets. The separated condensed water is returned to the flue gas absorption device 8 for recycling. After the mist-liquid separation, the flue gas enters the second-stage dust collector 10, which is the pulse bag filter, and further separates the remaining fine dust and sends it to the non-burning brick machine for resource disposal. At this time, the flue gas after the secondary dust removal is sent to the dust adsorption device 11 with a condenser, that is, the SXF-50 activated carbon adsorption device, and the activated carbon is used as the adsorbent to absorb the dust. After the adsorbent is saturated, high-temperature steam is sprayed from the bottom of the device. The organic solvent is evaporated, and the high-temperature organic vapor is condensed by the condenser to form waste water containing organic matter, which is passed into the dosing pool for subsequent purification. The remaining cooling water is sent to the condensation deacidification device 7 for recycling.

The wastewater discharged from the above-mentioned condensation deacidification device 7 and the wastewater desorbed and separated from the soot adsorption device 11 with a condenser are unified into the dosing pool 13, and the dosing pool is stirred under the action of alkaline chemicals to make the acidic wastewater in the pool generate middle and reaction to achieve the purpose of neutralizing the pH value. The wastewater after adjusting the pH value enters the organic wastewater treatment device 13 to remove organic matter. Based on the dynamic biofilm immobilization technology of the suspension carrier of the device, COD, ammonia nitrogen, total nitrogen, and total phosphorus in the wastewater can be effectively removed. The purified water is returned to the condensation deacidification unit as cooling water for recycling. The sludge discharged from the organic wastewater treatment device is dried in the drying pool 14 to form dried mud and sent to the non-burning brick machine for resource disposal.

In summary, the organic polluted soil thermal desorption system provided by the present invention solves the treatment of solid dust and waste liquid generated in the follow-up flue gas purification treatment while completing the remediation of organic polluted soil. The soil, including the solid particles and solid dust produced in the reverse thermal desorption device and the subsequent flue gas purification treatment, and the dried mud obtained after the treatment of organic wastewater, are all treated as resources by the non-burning brick machine, and the flue gas is discharged after purification. , and the waste water that has been treated by the organic waste water treatment device to remove organic matter is purified and recycled. In particular, the entire system is set in an air-supported greenhouse, and a greenhouse smoke and dust adsorption device is installed outside the shed to absorb the space gas in the shed, so that during the process of excavating the soil for treatment, it is possible to effectively avoid the generation of dust containing pollutants and the leakage of smoke from the system. Secondary pollution of the environment by gas and solid dust to achieve the purpose of environmental protection.

The above descriptions are only preferred embodiments of the present invention, and do not limit the structure of the present invention in any form. All simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims (3)

1. one kind does not produce the organic polluted soil thermal desorption system of secondary pollution to environment, comprise and process the reverse thermal desorption device of organic polluted soil and the first order deduster that exhanst gas outlet connects successively by flue gas pipeline thereof, dual firing chamber, condensation deacidifying device, flue gas absorbing device, gas-liquid separator, second level deduster, with the central computer control module of condenser flue dust adsorbent equipment and the operation of control whole system, it is characterized in that connecting by a dosing pond at the wastewater effluent mouth of described condensation deacidifying device the water inlet of an organic waste-water treating apparatus, the delivery port of described organic waste-water treating apparatus connects the cooling water intake of condensation deacidifying device, the mud mouth of organic waste-water treating apparatus connects the mud inlet in a dry pond, the delivery port of described gas-liquid separator connects the water inlet of described flue gas absorbing device, the described wastewater effluent mouth with condenser flue dust adsorbent equipment connects the water intake in described dosing pond, cooling water intake, its exhaust outlet that its cooling water outlet connects condensation deacidifying device is communicated with atmosphere with emission compliance flue gas, the dried mud outlet in the solid dust outlet of discharging opening, first order deduster and the second level deduster of described reverse thermal desorption device, dry pond is all connected to the charging aperture of a non-baking brick machine, the control port of described non-baking brick machine, dosing pond and organic waste-water treating apparatus connects respectively described central computer control module.

2. the organic polluted soil thermal desorption system that environment is not produced to secondary pollution according to claim 1, is characterized in that described system is arranged in air bearing booth.

3. the organic polluted soil thermal desorption system that environment is not produced to secondary pollution according to claim 2, is characterized in that the booth flue dust adsorbent equipment of space gas in described air bearing booth is provided with an absorption canopy outward.

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