System suitable for purification treatment of organic contaminated soil

Abstract

The utility model relates to a system suitable for purification treatment of organic contaminated soil, which comprises a thermal desorption unit, a primary purification unit, a secondary purification unit, a GWH heat exchanger and an adsorption unit which are connected in sequence, and further comprises a GGH heat exchanger, the thermal desorption unit is of an indirect heating structure and is internally provided with a soil channel and externally provided with a heating channel; the adsorption unit is connected with a recycled flue gas inlet in the heating channel through a purified flue gas pipeline, and a fan is arranged on the purified flue gas pipeline. According to the utility model, the organic polluted soil can be efficiently purified in an industrial plant, the operation is reliable, the investment and operation cost is low, the service life of equipment is long, and secondary pollution is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of organic contaminated soil remediation, in particular to a system suitable for purification and disposal of organic contaminated soil. Background Art

[0002] Organically contaminated soil refers to soil containing large amounts of organic pollutants, which adversely impact the environment and ecosystems. The main organic pollutants in soil include pesticides, chloral, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), petroleum, and methane. The main sources of organic pollutants include wastewater, waste, and emissions from industrial, agricultural, and urban activities. Organic soil pollution can reduce crop yields and cause pollutants to remain in plants. Therefore, the treatment and remediation of organically contaminated soil is a crucial measure to protect the soil environment and ensure the quality of agricultural products.

[0003] Currently, methods for decontaminating organically contaminated soil within industrial plants primarily include in-situ thermal desorption, rotary kiln co-treatment, and ex-situ incineration. However, these methods all present drawbacks. For example, while in-situ thermal desorption eliminates transportation issues, it consumes a lot of energy, is difficult to construct, and is unsuitable for clay soils. Rotary kiln co-treatment has drawbacks such as the need for qualified disposal companies and uncertain transportation distances. Ex-situ incineration requires the contaminated soil to be transported, which also presents challenges such as uncertain transportation distances and the spread of odor. Summary of the Invention

[0004] The utility model provides a system suitable for the purification and disposal of organic contaminated soil, which can realize the efficient purification of organic contaminated soil in industrial plants, and has reliable operation, low investment and operation costs, long equipment service life, and no secondary pollution.

[0005] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0006] A system suitable for the purification and disposal of organic contaminated soil comprises a thermal desorption unit, a primary purification unit, a secondary purification unit, a GWH heat exchanger, and an adsorption unit connected in sequence, and also comprises a GGH heat exchanger connected to the thermal desorption unit; the thermal desorption unit is an indirect heating structure, with a soil channel inside and a heating channel outside; a contaminated soil inlet is provided at one end of the soil channel, a purified soil outlet is provided at the other end, and the soil channel is also provided with a heating flue gas outlet; the heating channel is provided with a fuel inlet, a combustion-supporting air inlet, a combustion flue gas outlet, and a recycled flue gas inlet; the GGH heat exchanger is provided with a flue gas inlet, a flue gas outlet, a combustion-supporting air inlet, and a combustion-supporting air outlet; the flue gas inlet of the GGH heat exchanger is connected to the heating flue gas outlet of the soil channel, and the flue gas outlet of the GGH heat exchanger is connected to a chimney; the combustion-supporting air outlet of the GGH heat exchanger is connected to the combustion-supporting air inlet of the heating channel; the heating flue gas outlet of the soil channel is connected to the primary purification unit, and the adsorption unit is connected to the recycled flue gas inlet on the heating channel via a clean flue gas pipe, and a fan is provided on the clean flue gas pipe.

[0007] Furthermore, the purified soil outlet of the soil channel is connected to a discharging unit, and the discharging unit adopts a spiral discharging machine with humidification and cooling functions.

[0008] Furthermore, the first-level purification unit adopts a gravity dust collector or a cyclone dust collector.

[0009] Furthermore, the secondary purification unit adopts a bag dust collector, and the filter bags in the bag dust collector are high-temperature resistant filter bags.

[0010] Furthermore, the flue gas inlet of the GWH heat exchanger is connected to the flue gas outlet of the secondary purification unit, and the flue gas outlet of the GWH heat exchanger is connected to the flue gas inlet of the adsorption unit; the cooling water inlet and cooling water outlet of the GWH heat exchanger are respectively connected to the cooling unit; the cooling unit adopts a mechanical air-cooled cooling tower.

[0011] Furthermore, the adsorption unit is provided with high-performance adsorbents including activated carbon and molecular sieves.

[0012] Furthermore, the fan is a variable frequency fan.

[0013] Furthermore, the GGH heat exchanger adopts a fin-type indirect heat exchanger.

[0014] Furthermore, the GWH heat exchanger adopts a fin-type indirect heat exchanger.

[0015] Compared with the prior art, the beneficial effects of the present invention are:

[0016] 1) The thermal desorption unit adopts an indirect heating structure, which can minimize the amount of flue gas generated by heating the contaminated soil, saving the investment and operating costs of subsequent flue gas purification equipment;

[0017] 2) The thermal desorption unit uses natural gas or diesel as fuel to ensure that the combustion flue gas is safely discharged in compliance with emission standards;

[0018] 3) The discharging unit adopts a spiral discharging machine with humidification and cooling function, which can ensure that the purified soil is dust-free during the discharging process and improve the safety of the discharging;

[0019] 4) The use of two-stage purification units improves dust removal efficiency, ensures the removal effect of dust particles, and can effectively extend the service life of the secondary purification unit;

[0020] 5) When the secondary purification unit is a bag dust collector, high-temperature resistant filter bags are used to meet the dust removal efficiency while ensuring safe and reliable operation of the equipment;

[0021] 6) GWH heat exchanger and GGH heat exchanger are preferably finned indirect heat exchangers, which can maximize the heat exchange area, improve the heat exchange efficiency, achieve full heat recovery, and be low-carbon and environmentally friendly;

[0022] 7) The adsorption unit uses high-performance adsorbents such as activated carbon and molecular sieve to improve VOCs adsorption efficiency;

[0023] 8) Variable frequency fans are preferred for flue gas circulation, which are highly efficient and energy-saving;

[0024] 9) The cooling unit is preferably a mechanical air-cooled cooling tower, which can efficiently transfer heat, improve heat exchange efficiency, and ensure safe and stable operation of the system;

[0025] 10) The purified flue gas is returned to the thermal desorption unit for high-temperature combustion, which ensures the purification effect while recovering the flue gas heat, saving energy, reducing carbon emissions and being environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of a system suitable for purification and disposal of organic contaminated soil described in the utility model. DETAILED DESCRIPTION

[0027] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings:

[0028] like Figure 1As shown, the utility model describes a system suitable for the purification and disposal of organic contaminated soil, comprising a thermal desorption unit, a primary purification unit, a secondary purification unit, a GWH heat exchanger, and an adsorption unit connected in sequence, and also comprising a GGH heat exchanger connected to the thermal desorption unit; the thermal desorption unit is an indirect heating structure, with a soil channel inside and a heating channel outside; one end of the soil channel is provided with a contaminated soil inlet, and the other end is provided with a purified soil outlet, and the soil channel is also provided with a heating flue gas outlet; the heating channel is provided with a fuel inlet, a combustion-supporting air inlet, a combustion flue gas outlet and a recycled flue gas inlet; the GGH heat exchanger is provided with a flue gas inlet, a flue gas outlet, a combustion-supporting air inlet and a combustion-supporting air outlet; the flue gas inlet of the GGH heat exchanger is connected to the heating flue gas outlet of the soil channel, and the flue gas outlet of the GGH heat exchanger is connected to the chimney; the combustion-supporting air outlet of the GGH heat exchanger is connected to the combustion-supporting air inlet of the heating channel; the heating flue gas outlet of the soil channel is connected to the primary purification unit, and the adsorption unit is connected to the recycled flue gas inlet on the heating channel through a clean flue gas pipe, and a fan is provided on the clean flue gas pipe.

[0029] Furthermore, the purified soil outlet of the soil channel is connected to a discharging unit, and the discharging unit adopts a spiral discharging machine with humidification and cooling functions.

[0030] Furthermore, the first-level purification unit adopts a gravity dust collector or a cyclone dust collector.

[0031] Furthermore, the secondary purification unit adopts a bag dust collector, and the filter bags in the bag dust collector are high-temperature resistant filter bags.

[0032] Furthermore, the flue gas inlet of the GWH heat exchanger is connected to the flue gas outlet of the secondary purification unit, and the flue gas outlet of the GWH heat exchanger is connected to the flue gas inlet of the adsorption unit; the cooling water inlet and cooling water outlet of the GWH heat exchanger are respectively connected to the cooling unit; the cooling unit adopts a mechanical air-cooled cooling tower.

[0033] Furthermore, the adsorption unit is provided with high-performance adsorbents including activated carbon and molecular sieves.

[0034] Furthermore, the fan is a variable frequency fan.

[0035] Furthermore, the GGH heat exchanger adopts a fin-type indirect heat exchanger.

[0036] Furthermore, the GWH heat exchanger adopts a fin-type indirect heat exchanger.

[0037] The system for purifying and treating organically contaminated soil described in this utility model works as follows:

[0038] 1) The organically contaminated soil to be treated enters the thermal desorption unit through the feeding device for heating, causing the organic pollutants in the soil to volatilize or separate. The purified soil is humidified, cooled, and dusted by the discharging unit, and then reused after passing the test;

[0039] 2) The thermal desorption unit uses natural gas or diesel as fuel. The high-temperature flue gas after combustion exchanges heat with the combustion air in the GGH heat exchanger. The cooled flue gas is discharged through the chimney, and the combustion air is heated by heat exchange and enters the thermal desorption unit as combustion air.

[0040] 3) After the contaminated soil is heated in the desorption unit, the high-temperature flue gas is removed from the primary and secondary purification units, cooled in the GWH heat exchanger by the cooling unit, and then enters the adsorption unit to adsorb and purify the residual organic pollutants in the heated flue gas. The clean flue gas is returned to the heating channel of the thermal desorption unit by the fan and reused as combustion air;

[0041] 4) The target heating temperature of the thermal desorption unit is adjusted according to the boiling point of organic pollutants in the soil; the heating temperature for low-temperature thermal desorption is 100-200°C, the heating temperature for medium-temperature thermal desorption is 300-500°C, and the heating temperature for high-temperature thermal desorption is above 500°C; the residence time of contaminated soil in the soil channel is not less than 40 minutes.

[0042] The following embodiments are implemented based on the technical solution of the present utility model, and provide detailed implementation methods and specific operating processes, but the protection scope of the present utility model is not limited to the following embodiments.

[0043] [Example]

[0044] In this embodiment, a system suitable for purification and disposal of organic contaminated soil includes a thermal desorption unit, a discharge unit, a primary purification unit, a secondary purification unit, a GWH heat exchanger, an adsorption unit, a fan, a cooling unit, a GGH heat exchanger, a chimney, etc.

[0045] The thermal desorption unit is connected to the discharge unit via pipes. The thermal desorption unit, primary purification unit, secondary purification unit, GWH heat exchanger, adsorption unit, and fan are also connected via pipes to achieve a closed-loop circulation system. The GWH heat exchanger is connected to the cooling unit via pipes, and the thermal desorption unit, GGH heat exchanger, and chimney are also connected via pipes.

[0046] The thermal desorption unit utilizes an indirect heating structure. The internal soil channel features a contaminated soil inlet, a purified soil outlet, and a heated flue gas outlet. The external heating channel is equipped with a fuel inlet, a combustion air inlet, a combustion flue gas outlet, and a combustion air inlet. The purified soil outlet of the soil channel is connected to the discharge unit; the heated flue gas outlet of the soil channel is connected to the flue gas inlet of the primary purification unit. The combustion air inlet and combustion flue gas outlet of the heating channel are connected to the combustion air outlet and combustion flue gas inlet of the GGH heat exchanger, respectively. The recycled flue gas inlet of the heating channel is connected to the clean flue gas outlet of the adsorption unit via a fan.

[0047] In this embodiment, the thermal desorption unit uses natural gas as fuel.

[0048] In this embodiment, the discharging unit adopts a spiral discharging machine with humidification and cooling functions, that is, a cooling air inlet and a humidification water inlet are provided on the shell of the spiral discharging machine in the discharging stroke.

[0049] In this embodiment, the first-level purification unit adopts a cyclone dust collector, and the second-level purification unit adopts a bag dust collector with a high-temperature resistant filter bag.

[0050] In this embodiment, the GWH heat exchanger adopts a fin-type indirect heat exchanger, whose flue gas inlet and flue gas outlet are respectively connected to the secondary purification unit and the adsorption unit; its cooling water inlet and cooling water outlet are respectively connected to the cooling unit.

[0051] In this embodiment, the adsorption unit uses activated carbon adsorbent.

[0052] In this embodiment, the fan adopts a variable frequency fan, and its speed is controlled by a computer control system.

[0053] The cooling unit adopts a mechanical air-cooled cooling tower.

[0054] In this embodiment, the GGH heat exchanger adopts a fin-type indirect heat exchanger.

[0055] The target heating temperature of the thermal desorption unit is adjusted based on the boiling point of the organic pollutants in the soil. Data on the organic pollutants in the soil are pre-entered into a computer control system, which automatically controls the heating temperature of the thermal desorption unit. The contaminated soil remains in the soil channel for 40 minutes.

[0056] The above is only a preferred specific implementation method of the present invention, but the protection scope of the present invention is not limited to this. Any technician familiar with the technical field within the technical scope disclosed by the present invention can make equivalent replacements or changes based on the technical solution and inventive concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A system suitable for purification and disposal of organic contaminated soil, characterized in that: It includes a thermal desorption unit, a primary purification unit, a secondary purification unit, a GWH heat exchanger, and an adsorption unit connected in sequence, and also includes a GGH heat exchanger connected to the thermal desorption unit; the thermal desorption unit is an indirect heating structure, with a soil channel inside and a heating channel outside; a contaminated soil inlet is arranged at one end of the soil channel, a purified soil outlet is arranged at the other end, and the soil channel is also provided with a heating flue gas outlet; the heating channel is provided with a fuel inlet, a combustion-supporting air inlet, a combustion flue gas outlet and a recycled flue gas inlet; the GGH heat exchanger is provided with a flue gas inlet, a flue gas outlet, a combustion-supporting air inlet and a combustion-supporting air outlet; the flue gas inlet of the GGH heat exchanger is connected to the heating flue gas outlet of the soil channel, and the flue gas outlet of the GGH heat exchanger is connected to a chimney; the combustion-supporting air outlet of the GGH heat exchanger is connected to the combustion-supporting air inlet of the heating channel; the heating flue gas outlet of the soil channel is connected to the primary purification unit, and the adsorption unit is connected to the recycled flue gas inlet on the heating channel through a clean flue gas pipeline, and a fan is arranged on the clean flue gas pipeline.

2. A system suitable for purification and disposal of organic contaminated soil according to claim 1, characterized in that: The purified soil outlet of the soil channel is connected to a discharging unit, and the discharging unit adopts a spiral discharging machine with humidification and cooling functions.

3. A system suitable for purification and disposal of organic contaminated soil according to claim 1, characterized in that: The primary purification unit adopts a gravity dust collector or a cyclone dust collector.

4. A system suitable for purification and disposal of organic contaminated soil according to claim 1, characterized in that: The secondary purification unit adopts a bag dust collector, and the filter bags in the bag dust collector are high temperature resistant filter bags.

5. A system suitable for purification and disposal of organic contaminated soil according to claim 1, characterized in that: The flue gas inlet of the GWH heat exchanger is connected to the flue gas outlet of the secondary purification unit, and the flue gas outlet of the GWH heat exchanger is connected to the flue gas inlet of the adsorption unit; the cooling water inlet and cooling water outlet of the GWH heat exchanger are respectively connected to the cooling unit; the cooling unit adopts a mechanical air-cooled cooling tower.

6. A system suitable for purification and disposal of organic contaminated soil according to claim 1, characterized in that: The adsorption unit is provided with high-performance adsorbents including activated carbon and molecular sieves.

7. A system suitable for purification and disposal of organic contaminated soil according to claim 1, characterized in that: The fan is a variable frequency fan.

8. The system for purification and disposal of organic contaminated soil according to claim 1, characterized in that: The GGH heat exchanger is a fin-type indirect heat exchanger.

9. A system suitable for purification and disposal of organic contaminated soil according to claim 1, characterized in that: The GWH heat exchanger is a fin-type indirect heat exchanger.

Images