JP4979911B2 - Heat purification equipment for contaminated soil - Google Patents

Description

  The present invention relates to an apparatus for heating and purifying contaminated soil containing a volatile organic compound containing oil such as light oil and heavy oil.

  In recent years, there has been a problem that the soil in the site of the business establishment and the surrounding area has been contaminated by waste liquid of volatile pollutants such as oil, and the groundwater flowing under the soil has been contaminated with industrial activities. It has become. In order to treat soil contaminated in this way, the soil is purified by volatilizing, separating or decomposing volatile organic compounds that are soaked in the soil by heating.

  For example, Japanese Patent Application Laid-Open No. 2003-80229 discloses that a contaminated soil is heated and purified using a rotary kiln for heating soil, and a volatile organic compound in the dust collector and exhaust gas is disposed downstream of the rotary kiln for heating soil. In addition to having a deodorizing furnace that burns and decomposes, and the dust captured by the dust collector contains a large amount of volatile organic compounds, this dust heating rotary kiln is equipped with a dust heating rotary kiln that heats and purifies the dust. The dust is heated and purified, and the exhaust gas is reduced to a dust collector so that the fine particles scattered can be captured.

By the way, in order to burn all volatile organic compounds in the dust with the rotary kiln for heating the dust, it is necessary to expose to a high temperature. At this time, the exhaust gas temperature becomes a high temperature of about 400 ° C. Therefore, it was necessary to install a special dust collector using a ceramic filter with a high heat resistance temperature.
JP 2003-80229 A

  However, the ceramic filter is expensive, and even if dust containing a volatile organic compound is exposed to a high temperature in a rotary kiln for dust heating during the purification treatment of heavy oil contaminated soil, the high-boiling tar content will burn. Instead, it flows to the dust collector and the tar content adheres to the filter, causing a fire. Therefore, it has been a problem to provide a heat purification apparatus for contaminated soil that suitably heats and purifies contaminated soil containing a volatile organic compound.

In order to solve the above-described problems, the present invention is directed to a soil heating rotary kiln that heats and purifies contaminated soil, and a downstream of an exhaust flue of the soil heating rotary kiln. And a deodorizing furnace for burning and decomposing volatile organic compounds in the exhaust gas downstream of the dust collector, and for heating and purifying the contaminated soil, the dust trapped by the dust collector A dust heating rotary kiln for heating and purifying volatile organic compounds in dust is connected to the dust collector, and a small cyclone dust collector is installed in the middle of the exhaust flue of the dust heating rotary kiln. interposed therebetween, the tar content of high boiling point in the captured dust was further provided combustion decomposes small deodorizing furnace, discharge of from the soil heating rotary kiln That hot soil is disposed a soil cooling drum to cool, and wherein the exhaust flue of the captured combustion decomposed small deodorizing furnace tar of high boiling point in the dust that has been connected to the soil cooling drum It is in providing the heating purification apparatus of contaminated soil.

Further, to provide a heated purifier of contaminated soil, characterized in that arranged the bag filter type dust collecting processor downstream of the exhaust duct of the soil cooling drum.

  In addition, the exhaust flue before the bag filter dust collector downstream of the soil cooling drum is connected to introduce a predetermined amount of exhaust gas from the deodorizing furnace, and the temperature of the exhaust gas introduced into the bag filter dust collector is controlled. An object of the present invention is to provide a heating and purifying apparatus for contaminated soil, characterized in that it is adjusted to an appropriate temperature.

In the heating and purifying apparatus for contaminated soil according to claim 1 of the present invention, the dust captured by the dust collector that captures dust in the exhaust gas is heated downstream of the exhaust flue of the soil heating rotary kiln to A dust heating rotary kiln for purifying volatile organic compounds is disposed in connection with the dust collector, and a small cyclone dust collector is interposed in the middle of the exhaust flue of the dust heating rotary kiln and captured. A small deodorizing furnace that burns and decomposes high-boiling tar content in the dust is further installed, so dust containing a large amount of contaminants captured via the dust collector is supplied to the rotary kiln for heating the dust and rolls in the drum. While it flows down, it is exposed to the hot hot air of the burner, and volatile pollutants in the dust are burned and decomposed to be purified. The exhaust gas from the dust heating rotary kiln is led to a small cyclone dust collector and introduced into a small deodorizing furnace, and the high boiling point tar content derived from the exhaust gas without being burned and decomposed by the dust heating rotary kiln is removed. It can be burned and decomposed in a small deodorizing furnace, does not require a dust collector equipped with an expensive ceramic filter as in the past, and does not cause a fire in the dust collector, and is suitable for contaminated soil containing volatile organic compounds It can be heated and purified.
Then, a soil cooling drum is disposed so as to cool the high temperature soil discharged from the soil heating rotary kiln, and the exhaust flue of a small deodorizing furnace that burns and decomposes high boiling point tar content in the captured dust is provided as the soil. Since it is connected to the cooling drum, the high-temperature soil discharged from the rotary kiln for heating the soil can be cooled by the soil cooling drum, the treated soil is cooled to an appropriate temperature, and the moisture content is increased to the extent that dust is not easily generated. It becomes an easy state, can be transported without difficulty to a predetermined accumulation place in a factory by a conveyor or the like, and becomes a suitable apparatus for performing heat purification treatment of contaminated soil. Moreover, the high-temperature exhaust gas that has passed through the small deodorization furnace can be cooled by the soil cooling drum, so that it can be handled easily .

Further, in the heating purifier of contaminated soil according to claim 2, wherein according to the present invention, since the disposed bag filter type dust collecting processor downstream of the exhaust duct of the soil cooling drum, small type deodorizing furnace The high-temperature exhaust gas that has passed through can be cooled by a soil cooling drum and passed through a dust collector equipped with an inexpensive filter having a normal heat-resistant temperature, so that the high-temperature exhaust gas can be treated conveniently.

  Furthermore, in the heating and purifying apparatus for contaminated soil according to claim 3 according to the present invention, a predetermined amount of exhaust gas from the deodorizing furnace is disposed in the exhaust flue in front of the bag filter type dust collector disposed downstream of the soil cooling drum. Since the temperature of the exhaust gas to be introduced into the bag filter dust collector is adjusted to an appropriate temperature, even if the exhaust gas temperature passing through the soil cooling drum is too low, the bag filter dust collector The temperature of the exhaust gas introduced into the treatment machine can be adjusted to an appropriate temperature, and condensation does not occur in the dust collection treatment machine due to the temperature of the exhaust gas being too low.

The apparatus for heating and purifying contaminated soil of the present invention includes a rotary kiln for heating a soil that heats and purifies contaminated soil, a dust collector that captures dust in exhaust gas downstream of an exhaust flue of the rotary kiln for soil heating, and the dust collector A device for heating and purifying contaminated soil with a deodorizing furnace that burns and decomposes volatile organic compounds in exhaust gas downstream of the exhaust gas, and purifies the volatile organic compounds in the dust by heating the dust captured by the dust collector The dust heating rotary kiln is connected to the dust collector, and a small cyclone dust collector is interposed in the downstream of the exhaust flue of the dust heating rotary kiln so that the high boiling point tar in the trapped dust is collected. min further provided combustion decomposes small deodorizing furnace, soil cold to cool the hot soil discharged from the soil heating rotary kiln Disposed drum, is characterized in the exhaust duct of the captured combustion decomposed small deodorizing furnace tar of high boiling point in the dust that has been connected to the soil cooling drum.

  The contaminated soil heating and purifying apparatus heats and purifies soil excavated by volatile organic compounds such as light oil and heavy oil with a rotary kiln 1 for soil heating as shown in FIG. A cylindrical drum 2 having a large number of scraping blades arranged around the inner periphery of the soil heating rotary kiln 1 is rotatably supported on a machine base 3 and rotated at a predetermined speed by a predetermined driving device. Like to do.

  Then, hot air is sent into the drum 2 from the burner 5 disposed on the hot hopper 4 at one end of the drum 2, while the exhaust fan 8 interposed in the exhaust flue 7 connected to the cold hopper 6 at the other end. The exhaust gas is sucked to maintain a high-temperature gas flow passing through the drum 2.

  Then, the exhaust gas is introduced into a cyclone type dust collector 9 and a bag filter type dust collector 10 connected to the exhaust flue 7 so as to capture dust in the exhaust gas, and further volatilized in the exhaust gas in the deodorizing furnace 11 downstream of the dust collector 10. The organic compound is burned and decomposed and released from the chimney 12.

  The deodorizing furnace 11 is provided with a burner 13 for maintaining the furnace temperature at a predetermined value at one end. Exhaust gas introduced into the furnace is exposed to a high temperature atmosphere, and volatile contamination such as oil contained in the exhaust gas. The substance is burned and decomposed. The deodorization furnace 11 controls the combustion amount of the burner 13 so that the temperature in the furnace is maintained at a high temperature of, for example, about 750 ° C. or more so that the volatile pollutants can be completely burned and decomposed, and the exhaust gas passes through the furnace. It is preferable to secure a furnace length that takes at least 1 to 2 seconds or more to do so.

  Before introducing the deodorizing furnace 11, a cross-flow heat exchanger 14 is connected to exchange heat between the exhaust gas from the deodorizing furnace 11 and the exhaust gas from the heating rotary kiln 1. After the temperature of the exhaust gas is raised, it is introduced into the deodorization furnace 11 to reduce the amount of combustion of the burner 13 of the deodorization furnace 11. Furthermore, a heat exchanger 16 is also provided in the combustion air supply path for supplying the combustion air from the combustion air supply fan 15 to the burner 13 of the deodorizing furnace 11 to preheat the combustion air.

  Further, a predetermined amount of aggregate is discharged from an aggregate hopper group storing new aggregates by particle size, and the discharged aggregate is transferred from the cold hopper 6 side of the rotary kiln 1 for soil heating into the drum 2 via a belt conveyor. The drum 2 is brought into contact with a high-temperature gas flow while rolling down the drum 2 while being scraped up with a scraping blade, heated to a desired temperature, and discharged from the hot hopper 4 side as indicated by a dotted line.

  Furthermore, the dust captured by the cyclone type dust collector 9 contains a large amount of volatile pollutants, and is sent to the dust heating rotary kiln 18 via the feeder 17 in order to purify the dust. Yes. The dust captured by the bag filter type dust collector 10 is sent to the cyclone type dust collector 19 by a blower, and the captured dust is fed to the dust heating rotary kiln 18 through the feeder 20.

  The dust heating rotary kiln 18 has substantially the same structure as the soil heating rotary kiln 1 and rotatably supports a cylindrical drum 21 having a large number of scraping blades on the inner periphery thereof on a machine base 22. It is rotated at a predetermined speed by a driving device.

  Then, a burner 24 is provided on the side of the hot hopper 23 that receives dust at one end of the drum 21, and is sent from the burner 24 by an exhaust fan 26 interposed in the exhaust flue 25 connected to the cold hopper 27 at the other end. Hot air is sucked in to maintain a high-temperature gas flow that passes through the drum 21, dust captured by the dust collectors 9 and 10 is put into the drum 21 from the hot hopper 23, and dust is moved while rolling down the drum 21. I try to heat it.

  Further, a small cyclone dust collector 28 is connected in the middle of the exhaust flue 25 connected to the cold hopper 27 of the drum 21, and a small deodorizing furnace 30 for combusting and decomposing high-boiling tar content is connected. The high boiling point tar derived from the exhaust gas without being burned and decomposed by the heating rotary kiln 18 can be completely burned and decomposed. Although this small deodorizing furnace 30 has a small capacity for reducing the cost, the burner combustion amount is controlled so that the furnace temperature is maintained at a high temperature of about 750 ° C. or more as in the case of the deodorizing furnace 11 described above. The length of the furnace is preferably secured so that it takes 1-2 seconds or more for the exhaust gas to pass through the furnace.

  Further, the soil heated and purified by the dust heating rotary kiln 18 is supplied to the soil cooling drum 32 through the vertical elevator 44 and cooled to a temperature that is easy to handle. Further, dust captured by the cyclone type dust collector 28 and the small deodorizing furnace 30 is also supplied to the vertical elevator 44 through the feeder 31 and sent to the soil cooling drum 32 to be cooled.

  The soil cooling drum 32 supports a cylindrical drum 33 having a large number of scraping blades (not shown) on the inner periphery thereof so as to rotate on the machine base, and is driven by a driving device (not shown). It is made to rotate at a predetermined speed. A water spray nozzle is provided on the charging hopper 36 side of one end portion of the drum 32, and water is sprayed while the high temperature soil charged in the drum 32 is rolled down by the wings to appropriately wet and cool. As a state suitable for handling, the paper is sequentially discharged from the discharge hopper 37 side.

  Further, the exhaust flue 43 of the small deodorizing furnace 30 is connected to the soil cooling drum 32, and the exhaust gas of the small deodorizing furnace 30 is sucked by the exhaust fan 46 downstream of the exhaust flue 38 of the soil cooling drum 32. While passing through the inside 33, it is cooled and the gas temperature is lowered. In addition, a bag filter type dust collector 39 is disposed in the exhaust flue 38 to capture the fine particles scattered from the drum 33 and discharge the cleaned exhaust gas from the chimney 47. The fine particles captured by the dust collector 39 are returned to the soil cooling drum 32 by a blower and collected.

  Further, the branch duct 41 is branched from the exhaust flue 40 of the deodorizing furnace 11 and guided to the exhaust flue 38 in front of the bag filter type dust collector 39 through the damper 42 so that the air volume can be adjusted. Even if the temperature of the exhaust gas that has passed through the cooling drum 32 is too low, the temperature of the exhaust gas that is introduced into the bag filter type dust collector 39 can be adjusted to an appropriate temperature, and dew condensation occurs in the dust collector because the temperature of the exhaust gas is too low. Is not generated.

  Therefore, when purifying the contaminated soil, first, the oversized ones and foreign substances are removed by a pretreatment device such as a sieve or a magnetic separator, and the soiled rotary kiln 1 is introduced via a belt conveyor or the like. The contaminated soil is heated to a predetermined temperature by exposure to hot air. Volatile pollutants in the contaminated soil are volatile separated or burned and decomposed by this heating, while fine particles containing a large amount of volatile pollutants in the soil riding on the gas flow passing through the drum 2 are used for heating the soil. The contaminated soil is purified by scattering downstream of the rotary kiln 1.

  That is, the exhaust gas derived from the soil heating rotary kiln 1 is guided to the dust collectors 9 and 10 to capture dust containing a large amount of contaminants. The exhaust gas that has passed through the bag filter type dust collector 10 is further guided to a deodorizing furnace 11 where it is exposed to a high temperature atmosphere in the furnace, and volatile pollutants remaining in the exhaust gas are completely burned and decomposed.

Meanwhile, the dust containing a large amount of contaminants captured by the dust collector 9, a dust collector 10 is supplied to the dust heating rotary kiln 18, is exposed to the drum 21 at a high temperature of the hot air of the burner 24 during the rolling stream of dust Volatile pollutants inside are burned and decomposed to be purified. Further, the exhaust gas from the dust heating rotary kiln 18 is introduced into the small deodorizing furnace 30 through the small cyclone dust collector 28, and is derived from the exhaust gas without being burned and decomposed by the dust heating rotary kiln 18. The tar content is completely burned and decomposed, and there is no need for a dust collector equipped with an expensive ceramic filter as in the past, and there is no fire in the dust collector. Contaminated soil containing volatile organic compounds is suitably heated. It can be purified.

  Thus, the contaminated soil is purified by the rotary kiln 1 for heating the soil, while the dust containing the pollutants in the exhaust gas is captured by the dust collectors 9 and 10, and the contaminants not captured by the dust collectors 9 and 10 are The dust that is burned and decomposed in the deodorizing furnace 11 and trapped by the dust collectors 9 and 10 is burned and decomposed by the dust heating rotary kiln 18, and is discharged with the exhaust gas without being burned and decomposed by the dust heating rotary kiln 18. Since the tar content can be completely burned and decomposed in the small deodorizing furnace 30, the contaminated soil can be almost completely purified.

  Further, the heated soil discharged from the soil heating rotary kiln 1 and the heated dust discharged from the dust heating rotary kiln 18 are supplied to the soil cooling drum 32, and water spray nozzles while rolling down in the drum 33. The water is then sprayed and cooled.

  The amount of water sprayed from this water spray nozzle is determined by detecting the amount and temperature of the soil to be fed to the soil cooling drum 32 as appropriate, and determining and spraying the optimum amount of water. Even if the temperature changes, it is possible to prevent adhesion and clogging due to excessive humidification and to prevent generation of dust due to insufficient humidification.

  Thus, the soil heated by the soil heating rotary kiln 1 and the dust heated by the dust heating rotary kiln 18 are appropriately cooled by the soil cooling drum 32, so that the soil becomes easy to handle and can be easily processed. Therefore, the treated soil is cooled to an appropriate temperature, the moisture content is increased to such an extent that dust is difficult to come out, and it becomes easy to handle, and can be transported without difficulty to a predetermined accumulation place in the factory by a conveyor, It becomes an apparatus suitable for performing the heat purification process of contaminated soil.

  In addition, a soil cooling drum 32 is disposed so as to cool the high-temperature soil discharged from the soil heating rotary kiln 1, and the exhaust flue 43 of the small deodorizing furnace 30 is connected to the soil cooling drum 32 so that the soil cooling is performed. By installing a bag filter type dust collector 43 downstream of the exhaust flue 38 of the drum 32, the high temperature exhaust gas that has passed through the small deodorizing furnace 30 is cooled by the soil cooling drum 32, and the normal heat resistant temperature is low. The bag filter type dust collector 39 equipped with a filter can be passed, and high-temperature exhaust gas can be treated conveniently.

  Further, the bag filter type dust collector 39 is connected to the exhaust flue 38 in front of the bag filter type dust collector 39 downstream of the soil cooling drum 32 so as to introduce a predetermined amount of exhaust gas from the deodorizing furnace 11. By adjusting the temperature of the exhaust gas to be introduced to an appropriate temperature, even if the temperature of the exhaust gas that has passed through the soil cooling drum 32 is too low, the temperature of the exhaust gas to be introduced into the bag filter type dust collector 39 can be adjusted to an appropriate temperature. It is possible to prevent condensation in the dust collector 39 due to the temperature of the exhaust gas being too low.

It is a schematic block diagram which shows one Example of the contaminated soil purification apparatus which concerns on this invention.

DESCRIPTION OF SYMBOLS 1 ... Rotary kiln for soil heating 9, 10 ... Dust collector 11 ... Deodorizing furnace 18 ... Rotary kiln for dust heating 28 ... Cyclone type dust collector 30 ... Small deodorizing furnace 32 ... Soil cooling drum 39 ... Bag filter type dust collector

Claims (3)

A rotary kiln for heating soil that cleans and heats contaminated soil, a dust collector that captures dust in the exhaust gas downstream of the exhaust flue of the rotary kiln for soil heating, and a volatile organic compound in the exhaust gas downstream of the dust collector A device for heating and purifying contaminated soil, comprising a deodorizing furnace for burning and decomposing,
A dust heating rotary kiln that heats the dust trapped by the dust collector and purifies the volatile organic compounds in the dust is connected to the dust collector and disposed downstream of the exhaust flue of the dust heating rotary kiln. In addition, a small cyclone type dust collector is interposed between the two and a small deodorization furnace that burns and decomposes high boiling point tar content in the captured dust is further provided.
A soil cooling drum is disposed so as to cool the high temperature soil discharged from the soil heating rotary kiln, and the exhaust flue of a small deodorizing furnace that burns and decomposes high-boiling tar content in the captured dust is used as the soil cooling drum. A heating and purifying apparatus for contaminated soil, characterized by being connected to 該土 soil heating purifier of contaminated soil according to were provided with a bag filter type dust collecting processor downstream of the exhaust duct of the cooling drum to claim 1, characterized in.   The temperature of the exhaust gas to be introduced into the bag filter type dust collector by connecting the exhaust flue before the bag filter type dust collector in the downstream of the soil cooling drum to introduce a predetermined amount of exhaust gas from the deodorizing furnace. The apparatus for heating and purifying contaminated soil according to claim 2, wherein the temperature is adjusted to an appropriate temperature.

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