CN211953821U - A system for combined use of thermal desorption and waste heat recovery - Google Patents

Abstract

The utility model discloses a thermal desorption combined use and waste heat recovery system, which comprises a direct-heating thermal desorption system, an indirect-heating thermal desorption system, a tail gas purification and waste heat recycling system, wherein the direct-heating thermal desorption system consists of a direct-heating drying chamber, a conveyor and a direct-heating thermal desorption chamber which are sequentially connected through pipelines; the indirect-heating thermal desorption system consists of an indirect-heating drying chamber, a conveyor, an indirect-heating thermal desorption chamber, a condenser and an oil-water separator which are connected in sequence through pipelines; the tail gas purification and waste heat recycling system is composed of a cyclone dust collector, a high-temperature oxidation chamber, a first-stage heat conduction oil heat exchanger, a second-stage air heat exchanger and a tail gas treatment device which are sequentially connected through pipelines. The utility model classifies the pollutants, has large treatment capacity, high treatment efficiency, safety and environmental protection; the generated waste heat is recycled to the maximum extent, energy is saved, consumption is reduced, pollution is treated, and meanwhile, resource recovery is realized, and sustainable development is facilitated.

Description

A system for combined use of thermal desorption and waste heat recovery

technical field

The utility model relates to the technical field of soil remediation, in particular to a combined use of thermal desorption and waste heat recovery and utilization system.

Background technique

In recent years, for the treatment of organically polluted soil, thermal desorption technology has obvious advantages in terms of remediation cycle and remediation effect, and has gradually been popularized and applied in the field of soil remediation. At present, the development of thermal desorption technology at home and abroad is quite mature, and an industrial chain of thermal desorption technology has been formed. Thermal desorption equipment can be divided into direct thermal desorption and indirect thermal desorption according to the heating method. The difference between the two is mainly in the heating system and the exhaust gas treatment system. After the directly thermally desorbed polluted soil enters the thermal rotary kiln, it is in direct contact with the flame generated by the thermal rotary kiln burner, and is uniformly heated to a temperature above the gasification temperature of the target pollutant, so as to achieve the purpose of separating the pollutant from the soil. The direct thermal desorption system has the characteristics of high thermal efficiency and large processing capacity, but also has the disadvantages of large dust production and high safety hazards. The flame generated by the indirect thermal desorption burner uniformly heats the outside of the rotary kiln. After the polluted soil is indirectly heated to the boiling point of the pollutant, the pollutant is separated from the soil, and the exhaust gas is directly discharged after combustion, which has less dust generation and low safety hazard. , resource recovery and other advantages, but there are also some disadvantages, such as low thermal efficiency, small processing capacity and so on.

The two types of thermal desorption have their own advantages and disadvantages, but they are complementary. However, at present, a certain thermal desorption system is used alone in the market and projects. It has not been found that the combination of the two technologies can produce high temperature oxidation chambers. A report on the method and related equipment for the recovery and utilization of heat.

Utility model content

The technical problem to be solved by the utility model is to provide a combined use of thermal desorption and waste heat recovery and utilization system, which combines direct thermal thermal desorption and indirect thermal thermal desorption to treat organic polluted soil, sludge and mercury pollution The soil can not only give full play to the advantages of their respective equipment, improve the restoration efficiency, prevent secondary pollution from the restoration project, but also make full use of the waste heat of the system to save energy and reduce consumption.

The utility model solves the above-mentioned technical problems with the following technical solutions:

The thermal desorption combined use and waste heat recovery and utilization system of the utility model includes a direct thermal thermal desorption system, an indirect thermal thermal desorption system, a tail gas purification and a waste heat recycling system, and the direct thermal thermal desorption system is sequentially The direct heat drying chamber, the conveyor and the direct heat type thermal desorption chamber are connected by pipelines; Desorption chamber, condenser and oil-water separator; the exhaust gas purification and waste heat recycling system consists of a cyclone dust collector, a high temperature oxidation chamber, a primary heat transfer oil heat exchanger, and a secondary air heat exchanger which are connected by pipelines in sequence 2. It is composed of exhaust gas treatment device. The heat transfer oil input end of the primary heat transfer oil heat exchanger is connected to the oil storage tank, and the heat transfer oil output end of the first heat transfer oil heat exchanger is connected to the indirect thermal desorption chamber, The hot drying chamber and the oil storage tank are connected, the air input end of the secondary air heat exchanger is connected with the blower, and the hot air output end of the secondary air heat exchanger is connected with the direct heat drying chamber through pipes; The exhaust gas output end of the direct heat drying chamber is connected to the cyclone dust collector through a pipeline, and the non-condensable gas output end of the condenser is connected to the high temperature oxidation chamber through a pipeline.

The indirect thermal thermal desorption chamber of the utility model adopts a jacketed indirect thermal thermal desorption chamber, and the heat-conducting oil flows through the jacket arranged on the outside of the thermal desorption chamber, so that the polluted soil in the indirect thermal thermal desorption chamber is discharged. It is heated, and the jacket is wrapped with thermal insulation material.

The direct-heating thermal desorption chamber of the utility model adopts a direct-heating rotary kiln or a direct-heating chain plate type kiln.

The tail gas treatment device of the utility model is composed of a bag filter, an activated carbon adsorption tower, an induced draft fan and a chimney which are connected in sequence. The input end of the bag filter is connected with the waste gas output end of the secondary air heat exchanger.

Compared with the prior art, the utility model has the following advantages:

(1) Classified treatment, safety and environmental protection efficiency is high: the utility model separates oil sludge according to oil content level, organic polluted soil according to whether chlorine-containing pollutants, and direct-heating heat for oily sludge with low oil content and non-chlorine-containing organic polluted soil. Desorption system treatment, the oily sludge with high oil content, chlorine-containing organic polluted soil, and mercury-contaminated soil are treated with an indirect thermal thermal desorption system. The direct thermal thermal desorption system is used in combination with the indirect thermal thermal desorption system. Wider scope, larger processing capacity, and higher processing efficiency; classified processing, so that high-concentration petroleum hydrocarbons can be disposed of away from open flames, which is safer; avoid the generation of dioxins, which is more environmentally friendly; realize the recycling of oil, mercury and other resources, more economy.

(2) Resource recycling, less energy consumption: by recycling a large amount of heat generated by the system of the present utility model, the energy consumption is less, and the fuel cost is saved; at the same time, resources such as oil and mercury are recovered by the indirect thermal thermal desorption system. , to achieve pollution control at the same time to achieve economic income, more conducive to sustainable development.

Description of drawings

Fig. 1 is the operation process flow chart of the thermal desorption combined use and waste heat recovery and utilization system of the present invention.

FIG. 2 is a schematic structural diagram of the thermal desorption combined use and waste heat recovery and utilization system of the present invention.

In the figure: direct heating drying chamber 1, belt conveyor 2, direct heating thermal desorption chamber 3, feed hopper 31, flue gas outlet 32, discharge port 33, cyclone 4, high temperature oxidation chamber 5, first-level Heat transfer oil heat exchanger 6, oil storage tank 61, secondary air heat exchanger 7, blower 71, indirect thermal desorption chamber 8, feed port 81, jacket 82, discharge port 83, flue gas outlet 84 , Interheat drying chamber 9, screw conveyor 10, condenser 11, oil pump 12, oil-water separator 13, bag filter 14, activated carbon adsorption tower 15, induced draft fan 16, chimney 17.

Detailed ways

The technical solutions of the present utility model will be further described below in conjunction with the accompanying drawings.

As shown in Figure 1, the operating process flow of the thermal desorption combined use and waste heat recovery and utilization system of the present utility model includes the following processing steps:

(1) Drying and direct thermal desorption of low-concentration oily sludge and non-chlorinated organic polluted soil makes the soil temperature rise above the boiling point of the target pollutants. Dust removal treatment;

(2) Drying and indirect thermal desorption treatment of high-concentration oil sludge, chlorine-containing organic contaminated soil, and mercury-contaminated soil, so that the temperature of the contaminated soil rises to above the boiling point of the target pollutant, and the clean soil is discharged after treatment, and the resulting The waste gas is treated by condensation and oil-water separation in turn, the separated oil is recovered, and the separated sewage is treated and discharged after reaching the standard;

(3) The waste gas after the cyclone dust removal treatment in step 1) and the non-condensable gas produced by the condensation in step 2) are subjected to high-temperature oxidation treatment together, and then subjected to the cooling treatment of the primary heat transfer oil heat exchanger and the secondary air heat exchanger, and finally The exhaust gas is discharged after reaching the standard; the hot air of the secondary air heat exchanger is used as the drying heat source of step 1); the heat transfer oil of the primary heat transfer oil heat exchanger is used as the indirect heat desorption heat source of step 2), and the indirect heat Attach the treated heat transfer oil as the drying heat source in step 2), and then return the dried heat transfer oil to the primary heat transfer oil heat exchanger, thereby forming a waste heat recovery and utilization loop.

In the present invention, both the waste gas produced in step 1) drying treatment and the waste gas produced in step 2) drying treatment are sent to the cyclone dust removal treatment process.

According to the present invention, the moisture content of the contaminated soil after drying treatment in step 1) and in step 2) is not more than 20%.

The structure of the thermal desorption combined use and waste heat recovery and utilization system of the utility model is shown in Figure 2. The system is mainly composed of a direct thermal thermal desorption system, an indirect thermal thermal desorption system, a tail gas purification and a waste heat recycling system. The direct heat type thermal desorption system is composed of a direct heat drying chamber 1, a belt conveyor 2, and a direct heat type heat desorption chamber 3 connected by pipelines in sequence; The connected indirect heat drying chamber 9, the screw conveyor 10, the indirect heat thermal desorption chamber 8 provided with the jacket 82, the condenser 11, and the oil-water separator 13 are composed of the condenser 11 and the oil-water separator 13. There is an oil water pump 12; the exhaust gas purification and waste heat recycling system consists of a cyclone dust collector 4, a high temperature oxidation chamber 5, a first-level heat transfer oil heat exchanger 6, a second-level air heat exchanger 7, and a bag dust collector which are connected by pipelines in turn. 14, activated carbon adsorption tower 15, induced draft fan 16 and chimney 17, the heat transfer oil input end of the first heat transfer oil heat exchanger 6 is connected with the oil storage tank 61, and the heat transfer oil output end of the first heat transfer oil heat exchanger 6 The pipeline is connected to the jacket 82 of the indirect thermal desorption chamber 8, the heating oil circuit of the indirect thermal drying chamber 9, and the oil storage tank 61 in turn, and the air input end of the secondary air heat exchanger 7 is connected to the blower 71. , the hot air output end of the secondary air heat exchanger 7 is connected to the direct heat drying chamber 1 through the pipeline; the waste gas output end of the indirect heat drying chamber 1 and the direct heat drying chamber 9 is connected to the cyclone dust collector 4 through the pipeline, and the condenser The non-condensable gas output end of 11 is connected with the input end of the high temperature oxidation chamber 5 through a pipeline.

The heat-conducting oil of the first-stage heat-conducting oil heat exchanger 6 of the present invention flows through the jacket 82 arranged on the outer side of the indirect thermal thermal desorption chamber 8, so that the polluted soil in the indirect thermal thermal desorption chamber 8 is heated. The jacket 82 is wrapped with thermal insulation material.

The direct-heating thermal desorption chamber of the utility model adopts a direct-heating rotary kiln or a direct-heating chain plate type kiln.

The front end of the belt conveyor 2 is arranged inside the direct heat drying chamber 1, and the rear end of the belt conveyor 2 is connected to the feed hopper 31 of the direct heat type thermal desorption chamber 3, and the direct heat type heat desorption chamber 3 The flue gas outlet 32 is placed beside the feed hopper 31 and is connected to the air inlet of the cyclone 4, and the discharge port 33 for cleaning the soil is arranged at the end of the direct heating thermal desorption chamber 3.

The feed end of the screw conveyor 10 is arranged inside the indirect heat drying chamber 9, and the discharge end is connected to the feed port 81 of the indirect heat desorption chamber 8, and the flue gas of the indirect heat desorption chamber 8 is connected. The outlet 84 is set at the top of the tail end of the equipment, and the discharge port 83 is set at the bottom of the tail end of the equipment.

The flue gas inlet of the high temperature oxidation chamber 5 is connected with the gas outlet of the cyclone dust collector 4 , and the flue gas outlet of the high temperature oxidation chamber 5 is arranged at the rear end of the high temperature oxidation chamber 5 .

The primary heat transfer oil heat exchanger 6 and the secondary air heat exchanger 7 are connected in series through a heat preservation pipeline.

The process of applying the thermal desorption combined use and waste heat recovery and utilization system of the utility model is as follows:

(1) Drying and dehydration of waste heat: the heat of the high temperature oxidation chamber 5 is recovered by the secondary air heat exchanger 7 as the heat source of the direct heat drying chamber 1 of the direct heat type thermal desorption system; the indirect heat type thermal desorption chamber The medium-temperature heat-conducting oil from the jacket 82 of 20%.

(2) Direct thermal desorption: The initially dried sludge with low oil content (oil content ≤ 10%) or non-chlorinated organic polluted soil is transported to the direct thermal thermal desorption chamber 3, and heated directly by a flame Pollute the soil, so that the soil temperature rises above the boiling point of the target pollutant, so that the pollutants in the soil are vaporized and volatilized from the soil particles, and the generated exhaust gas is subjected to preliminary dust removal and then further high-temperature oxidation treatment;

(3) Indirect thermal desorption: The initially dried sludge with high oil content (oil content>10%) or chlorine-containing organic contaminated soil or mercury-contaminated soil is transported to the indirect thermal thermal desorption chamber 8, The heat transfer oil after heat exchange by the first-stage heat transfer oil heat exchanger 6 is used as the heat source of the indirect thermal thermal desorption chamber 8, and the temperature of the contaminated soil is raised to above the boiling point of the target pollutant through indirect heating of the heat transfer oil, so that the pollutants are removed from the soil particles. The exhaust gas is separated from the oil, and the generated tail gas is condensed to separate the oil and water and recover the oil, and the non-condensable gas generated is used as one of the fuels in the high temperature oxidation chamber.

(4) High-temperature oxidation treatment: the waste gas generated by the drying process of the direct heat drying chamber 1 and the indirect heat drying chamber 9, the tail gas generated by the direct heat type thermal desorption chamber and the non-condensable gas generated by the indirect heat type thermal desorption chamber all contain relatively high High organic pollutants are collected through pipes and fully burned and oxidized and decomposed under the treatment of high temperature oxidation chamber, and generate a lot of heat.

(5) Waste heat recovery and utilization: The huge heat generated by the high temperature oxidation chamber is first exchanged through the first-stage heat transfer oil heat exchanger 6, so that the high temperature flue gas processed by the high temperature oxidation chamber is reduced from about 1000 ° C to about 400 ° C, and the heat transfer oil Through heat exchange, the temperature is raised from room temperature to 400-500℃, and used as the heat source of the indirect thermal thermal desorption chamber; the temperature of the heat transfer oil from the indirect thermal thermal desorption chamber drops to 200-250℃, and then enters the indirect thermal desorption chamber. The front end of the system is used as the heat source of the intermediate heat drying chamber 9, and the cooled heat-conducting oil returns to the oil storage tank 61; the temperature of the flue gas after the primary heat exchange is 350-380 ℃, and further heat exchange with the cold air is carried out to make the smoke The air temperature drops to 150°C, and the cooled flue gas enters the exhaust gas treatment device for treatment; the temperature of the cold air rises to 150-200°C after heat exchange, and then returns to the front end of the direct heat thermal desorption system as direct heat drying Heat source for room 1.

(5) Tail gas treatment: The tail gas generated by the direct thermal thermal desorption system and the indirect thermal thermal desorption system is discharged into the atmosphere after the dust removal and adsorption treatment reaches the standard.

The working principle of the system of the utility model is as follows: the sludge is treated separately according to the level of oil content or the organic polluted soil according to whether it contains chlorine pollutants or not, and the sludge with low oil content and the non-chlorine-containing organic polluted soil are treated by a direct heat thermal desorption system. The oily sludge with high oil content, chlorine-containing organic polluted soil, and mercury-contaminated soil are treated with indirect thermal thermal desorption system, and the direct thermal thermal desorption system and indirect thermal thermal desorption system are used in parallel to increase the processing capacity of the entire system. increase, the treatment efficiency is improved, and the secondary pollution such as dioxin is avoided at the same time. The organic waste gas, tail gas and other gases generated by the direct thermal thermal desorption chamber 3 and the indirect thermal thermal desorption chamber 8 are collected and burned and decomposed in the high temperature oxidation chamber 5, and a large amount of heat is generated while the organic matter is decomposed. The outgoing flue gas belongs to high-temperature flue gas. The heat of the high-temperature flue gas is multi-stage heat exchanged by the primary heat transfer oil heat exchanger 6 and the secondary air heat exchanger 7, and the recovered energy is reused for indirect thermal desorption. Chamber 8 and the direct heating drying chamber 1 and the indirect heating drying chamber 9 at the front of the system, the cooled heat transfer oil is returned to the oil storage tank 61 for recycling, realizing the reuse of waste heat of the entire system, minimizing heat loss, and saving energy and reducing consumption. , conducive to sustainable development.

Claims (4)

1. A thermal desorption combined use and waste heat recovery system is characterized by comprising a direct-heating thermal desorption system, an indirect-heating thermal desorption system and a tail gas purification and waste heat recycling system, wherein the direct-heating thermal desorption system consists of a direct-heating drying chamber, a conveyor and a direct-heating thermal desorption chamber which are sequentially connected through pipelines; the indirect-heating thermal desorption system consists of an indirect-heating drying chamber, a conveyor, an indirect-heating thermal desorption chamber, a condenser and an oil-water separator which are connected in sequence through pipelines; the tail gas purification and waste heat recycling system comprises a cyclone dust collector, a high-temperature oxidation chamber, a primary heat conduction oil heat exchanger, a secondary air heat exchanger and a tail gas treatment device which are sequentially connected through pipelines, wherein the heat conduction oil input end of the primary heat conduction oil heat exchanger is connected with an oil storage tank, the heat conduction oil output end of the primary heat conduction oil heat exchanger is sequentially connected with an indirect heating type heat desorption chamber, an indirect heating drying chamber and the oil storage tank through pipelines, the air input end of the secondary air heat exchanger is connected with an air blower, and the hot air output end of the secondary air heat exchanger is connected with a direct heating drying chamber; the waste gas output ends of the indirect heat drying chamber and the direct heat drying chamber are connected with a cyclone dust collector through pipelines, and the non-condensable gas output end of the condenser is connected with the high-temperature oxidation chamber through a pipeline.

2. The system for combined use of thermal desorption and waste heat recovery and utilization according to claim 1, wherein the indirect thermal desorption chamber is a jacketed indirect thermal desorption chamber, the heat transfer oil flows through a jacket arranged outside the thermal desorption chamber to heat the contaminated soil in the indirect thermal desorption chamber, and the jacket is wrapped with a heat insulation material.

3. The thermal desorption combined use and waste heat recovery system as claimed in claim 1, wherein the direct-heating thermal desorption chamber adopts a direct-heating rotary kiln or a direct-heating chain plate kiln.

4. The thermal desorption combined use and waste heat recovery system according to claim 1, wherein the tail gas treatment device comprises a bag-type dust collector, an activated carbon adsorption tower, an induced draft fan and a chimney which are connected in sequence, and the input end of the bag-type dust collector is connected with the waste gas output end of the secondary air heat exchanger.

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