CN111336537A - Indirect thermal desorption system of rotary kiln for soil restoration - Google Patents

Abstract

The invention discloses an indirect thermal desorption system of a rotary kiln for soil restoration, which comprises: feed arrangement, rotary kiln, discharge device, second combustion chamber and heat exchanger, the rotary kiln includes: the kiln comprises a kiln head, a base, a rotary kiln outer sleeve, a rotary kiln inner sleeve and a kiln tail, wherein the rotary kiln inner sleeve is arranged in the rotary kiln outer sleeve to form a hot air interlayer, the rotary kiln outer sleeve is arranged on the base, the kiln head and the kiln tail are respectively arranged at two ends of the rotary kiln outer sleeve, a feeding device is connected with the kiln head, a discharging device is connected with the kiln tail, a heat exchanger is arranged on a secondary combustion chamber, the heat exchanger is connected with the hot air interlayer, and the secondary combustion chamber is connected with the kiln tail. According to the invention, the heat of combustion in the secondary combustion chamber is introduced into the hot air interlayer through the heat exchanger to heat the polluted soil, so that the energy utilization rate of the indirect thermal desorption system of the rotary kiln for soil remediation is improved.

Description

A rotary kiln indirect thermal desorption system for soil remediation

technical field

The invention relates to the technical field of soil remediation, in particular to a rotary kiln indirect thermal desorption system for soil remediation.

Background technique

The harm of soil pollution is that after some organic matter pollutes the soil, it will further pollute the atmosphere and water around the soil, while some organic matter or heavy metal pollution will have adverse effects on the human body through the food chain. Thermal desorption technology is one of the effective technologies for remediating polluted soil. Thermal desorption technology is to heat the target pollutants in the polluted soil above its boiling point through direct or indirect heating, and selectively control the temperature of the system and the residence time of the material. Promote the gasification and volatilization of pollutants, so that the target pollutants and soil particles can be separated and removed. When using the direct or indirect thermal desorption system to remediate soil, to prevent the production of dioxins, the high temperature flue gas generated in the secondary combustion chamber should be rapidly cooled. In this process, a large amount of energy contained in the high-temperature flue gas is often directly wasted, and the energy utilization efficiency is low.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a rotary kiln indirect thermal desorption system for soil remediation, so as to solve the technical problem of low energy utilization rate of the existing rotary kiln indirect thermal desorption system for soil remediation.

In order to achieve the above purpose, the present invention provides a rotary kiln indirect thermal desorption system for soil remediation, comprising: a feeding device, a rotary kiln, a discharging device, a secondary combustion chamber and a heat exchanger, and the rotary kiln includes: a kiln head, base, rotary kiln jacket, rotary kiln inner jacket and kiln tail, the rotary kiln inner jacket is arranged in the rotary kiln jacket to form a hot air interlayer, the rotary kiln jacket is arranged on the base, the kiln jacket The head and the kiln tail are respectively arranged at both ends of the outer casing of the rotary kiln, the feeding device is connected with the kiln head, the discharging device is connected with the kiln tail, and the heat exchanger is arranged at the kiln head. On the secondary combustion chamber, the heat exchanger is connected with the hot air interlayer, and the secondary combustion chamber is connected with the kiln tail.

Optionally, the discharging device includes: a clean soil outlet and a humidifier, and the clean soil outlet is connected to the humidifier and the kiln end.

Optionally, the discharging device further includes a waste heat dryer, and the waste heat dryer includes: a drying pipe, a first auger, a second auger, a socket, a first end cover, a second end cover, a first A motor and a second motor, the first auger is arranged in the drying tube, the first auger includes a center hole, the second auger is arranged in the center hole, and the first end cover and the second end cover are respectively arranged at both ends of the drying tube, the nipple is arranged on one side of the first end cover and communicated with the central hole, and the first motor is arranged on the nipple and connected to the second auger, the first auger is connected to the second motor at one end away from the nipple, the end of the drying pipe away from the nipple is provided with an original soil inlet, and the drying pipe A raw soil outlet is provided near one end of the nipple, a clean soil inlet is provided on the nipple, the clean soil inlet is connected to the kiln tail, and a clean soil outlet is provided at one end of the central hole away from the nipple .

Optionally, the feeding device includes: a feeding hopper and a conveyor belt, and the conveyor belt connects the kiln head and the feeding hopper.

Optionally, the outer casing of the rotary kiln is provided with a first burner for heating the hot air interlayer.

Optionally, a second burner is provided on the secondary combustion chamber.

Optionally, a fuel storage device is provided between the first burner and the second burner.

Optionally, an explosion-proof valve is provided at one end of the secondary combustion chamber away from the rotary kiln.

Optionally, one end of the secondary combustion chamber away from the rotary kiln is sequentially connected with a cyclone dust collector, a bag filter, an induced draft fan and a chimney.

The invention provides an indirect thermal desorption system of a rotary kiln for soil remediation, comprising: a feeding device, a rotary kiln, a discharging device, a secondary combustion chamber and a heat exchanger. The rotary kiln comprises: a kiln head, a base, and a rotary kiln The outer jacket, the inner jacket of the rotary kiln and the kiln tail, the inner jacket of the rotary kiln is arranged in the outer jacket of the rotary kiln to form a hot air interlayer, the outer jacket of the rotary kiln is arranged on the base, the kiln head and the kiln tail They are respectively arranged at both ends of the outer casing of the rotary kiln, the feeding device is connected to the kiln head, the discharging device is connected to the kiln tail, and the heat exchanger is arranged on the secondary combustion chamber, so The heat exchanger is connected with the hot air interlayer, and the secondary combustion chamber is connected with the kiln tail. The invention introduces the heat of combustion in the secondary combustion chamber into the hot air interlayer to heat the polluted soil through the heat exchanger, thereby improving the energy utilization rate of the indirect thermal desorption system of the rotary kiln used for soil remediation.

Description of drawings

1 is a schematic diagram of an indirect thermal desorption system of a rotary kiln for soil remediation provided by an embodiment of the present invention;

2 is a schematic diagram of a discharging device provided by an embodiment of the present invention;

FIG. 3 is a schematic diagram of a waste heat dryer provided by an embodiment of the present invention.

Among them: 1-feed hopper, 2-conveyor belt, 3-kiln head, 4-base, 5-rotary kiln jacket, 6-rotary kiln inner jacket, 7-first burner, 8-fuel storage device, 9- Kiln tail, 10- humidifier, 11- clean soil outlet, 12- second burner, 13- second combustion chamber, 14- heat exchanger, 15- explosion-proof valve, 16- second combustion chamber chimney, 17- cyclone dust collector , 18- bag filter, 19- induced draft fan, 20- chimney, 21- hot steam pipe, 22- waste heat dryer, 23- raw soil inlet, 24- raw soil outlet, 25- clean soil inlet, 26- drying pipe , 27-first auger, 28-second auger, 29-socket, 30-first end cap, 31-second end cap, 32-first motor, 33-second motor, 34-air.

Detailed ways

The specific embodiments of the present invention will be described in more detail below with reference to the schematic diagrams. The advantages and features of the present invention will become apparent from the following description and claims. It should be noted that, the accompanying drawings are all in a very simplified form and in inaccurate scales, and are only used to facilitate and clearly assist the purpose of explaining the embodiments of the present invention.

1 is a schematic diagram of an indirect thermal desorption system of a rotary kiln for soil remediation provided by an embodiment of the present invention. Referring to FIG. 1 , the indirect thermal desorption system of a rotary kiln for soil remediation includes: a feeding device, a rotary kiln, a discharge The rotary kiln includes: a kiln head 3, a base 4, a rotary kiln outer casing 5, a rotary kiln inner casing 6 and a kiln tail 9, and the rotary kiln inner casing 6 is arranged on the A hot air interlayer is formed in the outer casing 5 of the rotary kiln. The outer casing 5 of the rotary kiln is arranged on the base 4, and the kiln head 3 and the kiln tail 9 are respectively arranged at both ends of the outer casing 5 of the rotary kiln. The feeding device is connected to the kiln head 3, the discharging device is connected to the kiln tail 9, the heat exchanger 14 is arranged on the secondary combustion chamber 13, and the heat exchanger 14 is connected to the kiln tail 9. The hot air is interlayer connected, and the second combustion chamber 13 is connected with the kiln tail 9 . After pretreatment measures such as screening, crushing and moisture content adjustment, the raw soil of the contaminated soil is sent to the rotary kiln by the feeding device, and is indirectly heated by hot air to the preset temperature in the rotary kiln. The pollutants are separated from the soil and desorbed. The clean soil is cooled and its water content is adjusted. After passing the inspection, it is transferred or temporarily stored in the stockyard for site backfilling; the desorbed hot steam containing pollutants is fully burned in the secondary combustion chamber to form high-temperature flue gas, and the high-temperature flue gas passes through The heat exchanger forms low-temperature flue gas and discharges it. After the air 34 is introduced into the heat exchanger, it absorbs the heat of the high-temperature flue gas to form hot air. The hot air is then introduced into the hot air interlayer to indirectly heat the polluted soil, thereby improving the indirect heat of the rotary kiln for soil remediation. Energy utilization of the desorption system.

FIG. 2 is a schematic diagram of a discharging device provided by an embodiment of the present invention, and FIG. 3 is a schematic diagram of a waste heat dryer provided by an embodiment of the present invention. Referring to FIGS. 1-3 , the discharging device includes: a cleaning soil outlet 11 , humidifier 10 and waste heat dryer 22 . The waste heat dryer 22 includes: a drying pipe 26, a first auger 27, a second auger 28, a socket 29, a first end cover 30, a second end cover 31, a first motor 32 and a second motor 33, The first auger 27 is arranged in the drying pipe 26, the first auger 27 includes a central hole arranged along the extending direction of its axis, and the second auger 28 is arranged in the central hole, The first auger 27 feeds the soil from left to right, and the second auger 28 feeds the soil from right to left. The first end cap 30 and the second end cap 31 are respectively disposed on both ends of the drying tube 26, and the nipple 29 is disposed on one side of the first end cap 30 and communicates with the central hole. The first end cover 30 includes a through hole, the end surface of the connecting sleeve 29 and the first auger 27 are in contact and the contact surface is located in the through hole of the connecting sleeve 29, and the first auger 27 is rotatable. The nipple 29 is fixedly connected to the end cover 30 . The first motor 32 is disposed on the socket 29 and connected to the second auger 28 , and one end of the first auger 27 away from the socket 29 is connected to the second motor 33 . One end of the drying pipe 26 away from the nipple 29 is provided with a raw soil inlet 23 , one end of the drying pipe 26 close to the nipple 29 is provided with a raw soil outlet 24 , and the nipple 29 is provided with a clean soil inlet 25 , the cleaning soil inlet 25 is connected to the kiln tail 9 , and the cleaning soil outlet 11 is provided at one end of the central hole away from the nipple 29 . The cleaning soil outlet 11 is connected to the humidifier 10 and the drying pipe 26 . The existing thermal desorption system is mainly aimed at polluted soil with moisture lower than 20%. Excessive moisture can easily lead to a sharp increase in the energy consumption of the device. At the same time, during the rainy season, the polluted soil is prone to the problem of not being able to enter the kiln normally due to the high viscosity of the moisture. . On the other hand, the temperature of the soil just after thermal desorption is usually higher than 300 ℃, which has a good value of waste heat utilization. Therefore, if the waste heat of the soil after thermal desorption can be efficiently used to dry the soil into the kiln, it can not only reduce the energy consumption of the thermal desorption device, but also improve the stability and reliability of the device operation. In the present invention, dry hot clean soil is introduced from the clean soil inlet 25, and the moist contaminated soil raw soil is introduced from the raw soil inlet 23, and the heat of the dry hot clean soil is transferred to the raw soil of the polluted soil through the first auger 27, adjusting the The water content of the original soil of the contaminated soil. The feeding device includes: a feeding hopper 1 and a conveyor belt 2 , and the conveyor belt 2 connects the kiln head 3 and the feeding hopper 1 . The raw soil of the dry contaminated soil adjusted by the water content enters the rotary kiln through the feed hopper 1, the clean soil after heat exchange is exported from the clean soil outlet 11, and the water content is adjusted by the humidifier 10. After passing the inspection, it is transferred or temporarily stored in the heap The stockyard is used for site backfilling.

1-3, the rotary kiln jacket 5 is provided with a first burner 7 for heating the hot air interlayer, the second combustion chamber 13 is provided with a second burner 12, the A fuel storage device 8 is arranged between a burner 7 and the second burner 12 to provide fuel for the first burner 7 and the second burner 12 . An explosion-proof valve 15 and a chimney of the secondary combustion chamber are provided at one end of the secondary combustion chamber 13 away from the rotary kiln. One end of the secondary combustion chamber 13 away from the rotary kiln is connected with a cyclone 17 , a bag filter 18 , an induced draft fan 19 and a chimney 20 in sequence. The desorbed hot steam containing pollutants is fully burned in the secondary combustion chamber 13 to form high temperature flue gas, the high temperature flue gas passes through the heat exchanger 14 to form low temperature flue gas, and the low temperature flue gas successively enters the cyclone dust collector 17 and the bag filter 18 for dust removal , the clean exhaust gas after dust removal is discharged through the chimney 20 through the induced draft fan 19 .

To sum up, in the indirect thermal desorption system of a rotary kiln for soil remediation provided by the embodiment of the present invention, the indirect thermal desorption system of a rotary kiln for soil remediation includes: a feeding device, a rotary kiln, a discharging device, two A combustion chamber and a heat exchanger, the rotary kiln includes: a kiln head, a base, a rotary kiln jacket, a rotary kiln inner jacket and a kiln tail, and the rotary kiln inner jacket is arranged in the rotary kiln jacket to form a hot air interlayer, so The outer casing of the rotary kiln is arranged on the base, the kiln head and the kiln tail are respectively arranged at both ends of the outer casing of the rotary kiln, the feeding device is connected with the kiln head, and the discharging device is connected with the kiln head. The kiln tail is connected, the heat exchanger is arranged on the secondary combustion chamber, the heat exchanger is connected with the hot air interlayer, and the secondary combustion chamber is connected with the kiln tail. The invention introduces the heat of combustion in the secondary combustion chamber into the hot air interlayer to heat the polluted soil through the heat exchanger, thereby improving the energy utilization rate of the indirect thermal desorption system of the rotary kiln used for soil remediation.

The above are only preferred embodiments of the present invention, and do not have any limiting effect on the present invention. Any person skilled in the art, within the scope of not departing from the technical solution of the present invention, makes any form of equivalent replacement or modification to the technical solution and technical content disclosed in the present invention, all belong to the technical solution of the present invention. content still falls within the protection scope of the present invention.

Claims (9)

1. The utility model provides an indirect thermal desorption system of rotary kiln for soil remediation which characterized in that includes: feed arrangement, rotary kiln, discharge device, second combustion chamber and heat exchanger, the rotary kiln includes: the kiln comprises a kiln head, a base, a rotary kiln outer sleeve, a rotary kiln inner sleeve and a kiln tail, wherein the rotary kiln inner sleeve is arranged in the rotary kiln outer sleeve to form a hot air interlayer, the rotary kiln outer sleeve is arranged on the base, the kiln head and the kiln tail are respectively arranged at two ends of the rotary kiln outer sleeve, a feeding device is connected with the kiln head, a discharging device is connected with the kiln tail, a heat exchanger is arranged on a secondary combustion chamber, the heat exchanger is connected with the hot air interlayer, and the secondary combustion chamber is connected with the kiln tail.

2. The indirect thermal desorption system of a rotary kiln for soil remediation according to claim 1, wherein the discharge device comprises: the clean soil outlet is connected with the humidifier and the kiln tail.

3. The indirect thermal desorption system of rotary kiln for soil remediation as claimed in claim 2, wherein the discharge device further comprises an exhaust heat dryer, the exhaust heat dryer comprising: a drying tube, a first screw conveyor, a second screw conveyor, a connecting sleeve, a first end cover, a second end cover, a first motor and a second motor, the first screw conveyor is arranged in the drying pipe and comprises a central hole, the second screw conveyor is arranged in the central hole, the first end cover and the second end cover are respectively arranged at two ends of the drying pipe, the sleeve is arranged at one side of the first end cover and is communicated with the central hole, the first motor is arranged on the connecting sleeve and is connected with the second auger, one end of the first auger, which is far away from the connecting sleeve, is connected with the second motor, the end of the drying tube far away from the connecting sleeve is provided with a raw soil inlet, the end of the drying tube near the connecting sleeve is provided with a raw soil outlet, the connecting sleeve is provided with a clean soil inlet, the clean soil inlet is connected with the kiln tail, and one end, far away from the connecting sleeve, of the central hole is provided with a clean soil outlet.

4. The indirect thermal desorption system of a rotary kiln for soil remediation according to claim 1, wherein the feed device comprises: feeder hopper and conveyer belt, the conveyer belt is connected the kiln head with the feeder hopper.

5. The indirect thermal desorption system of a rotary kiln for soil remediation as claimed in claim 1 wherein a first burner for heating the hot air jacket is provided on the rotary kiln jacket.

6. The indirect thermal desorption system of a rotary kiln for soil remediation according to claim 5, wherein a second burner is provided on the second combustion chamber.

7. The indirect thermal desorption system of a rotary kiln for soil remediation according to claim 6, wherein a fuel storage device is provided between the first burner and the second burner.

8. The indirect thermal desorption system of a rotary kiln for soil remediation as recited in claim 1, wherein an explosion-proof valve is disposed at an end of the secondary combustion chamber away from the rotary kiln.

9. The indirect thermal desorption system of a rotary kiln for soil remediation according to claim 1, wherein one end of the secondary combustion chamber, which is far away from the rotary kiln, is sequentially connected with a cyclone dust collector, a bag-type dust collector, an induced draft fan and a chimney.

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