Cooling cleaning system and cooling cleaning method

Abstract

This cooling cleaning system comprises: a cooling device that sprays first cooling water into a reformed gas discharged from a gasification melting furnace, evaporates the first cooling water, and cools the reformed gas; a sedimentation tank that stores the first cooling water discharged from the cooling device and separates a solid contained in the first cooling water; a cleaning device that sprays second cooling water into the reformed gas cooled by the cooling device and discharged, condenses water vapor contained in the reformed gas, and cools and cleans the reformed gas; and a heat exchanger that cools the second cooling water discharged from the cleaning device. The first cooling water from which the solid has been separated in the sedimentation tank is sent to the cooling device and sprayed into the reformed gas, and part of the second cooling water sprayed into the reformed gas in the cleaning device merges with the first cooling water.

Description

Cooling cleaning system and cooling cleaning method

[0001] The present invention relates to a cooling washing system and a cooling washing method.

[0002] One example of an invention for cooling high-temperature gas is the cooling method disclosed in Patent Document 1. The cooling method disclosed in Patent Document 1 cools crude synthesis gas generated in a high-temperature reactor for incinerating waste by injecting water in two stages into the crude synthesis gas. Dust and other particles contained in the crude synthesis gas are removed by the cooling water injected into the crude synthesis gas, and the water containing the dust and other particles after cooling the crude synthesis gas is recycled via a settler.

[0003] Special Publication No. 2003-522020

[0004] In the method of injecting cooling water into the crude synthesis gas as disclosed in Patent Document 1, dust contained in the crude synthesis gas falls into the water. When cooling water is circulated after being cooled in a heat exchanger, dust may clog the heat exchanger, reducing the flow rate of the cooling water. Furthermore, if the flow rate of the cooling water decreases due to blockage of the heat exchanger, the cooling capacity of the crude synthesis gas will decrease. One method to prevent blockage of the heat exchanger is to install an auto-strainer, but the large amount of dust requires frequent maintenance of the heat exchanger, which increases operating costs. Furthermore, if a large amount of dust falls into the water in the room where the crude synthesis gas is cooled, scum is likely to form. This scum causes blockage of piping, requiring maintenance and hindering stable operation of the high-temperature reactor.

[0005] The present invention has been made in view of the above, and has an object to prevent blockage of a circulation path of cooling water that cools gas containing dust.

[0006] A cooling and cleaning system according to one aspect of the present invention comprises a cooling device that injects first cooling water onto reformed gas discharged from a gasification and melting furnace and evaporates the first cooling water to cool the reformed gas; a settling tank that stores the first cooling water discharged from the cooling device and separates solids contained in the first cooling water; a cleaning device that injects second cooling water onto the reformed gas cooled and discharged by the cooling device and condenses water vapor contained in the reformed gas to cool and clean the reformed gas; and a heat exchanger that cools the second cooling water discharged from the cleaning device, wherein the first cooling water from which the solids have been separated in the settling tank is sent to the cooling device and injected into the reformed gas, and a portion of the second cooling water injected into the reformed gas by the cleaning device is combined with the first cooling water.

[0007] In the present invention, the temperature of the reformed gas cooled by the first cooling water in the cooling device may be 80° C. or higher.

[0008] In the present invention, the temperature of the first cooling water injected into the reformed gas may be 70° C. or higher.

[0009] In the present invention, the temperature of the second cooling water injected into the reformed gas may be 30° C. or higher and 75° C. or lower.

[0010] In the present invention, the temperature of the reformed gas cooled in the cleaning device may be 50°C or higher and 80°C or lower.

[0011] A cooling and cleaning method according to one aspect of the present invention includes a cooling step of injecting first cooling water in a cooling device onto reformed gas discharged from a gasification and melting furnace and evaporating the first cooling water to cool the reformed gas; a separation step of separating solids contained in the first cooling water in a settling tank that stores the first cooling water discharged from the cooling device; a cleaning step of injecting second cooling water in a cleaning device onto the reformed gas cooled and discharged in the cooling device and condensing water vapor contained in the reformed gas to cool and clean the reformed gas; and a heat exchange step of cooling the second cooling water discharged from the cleaning device in a heat exchanger, wherein the first cooling water from which the solids have been separated in the settling tank is sent to the cooling device and injected into the reformed gas, and a portion of the second cooling water injected into the reformed gas in the cleaning device is merged with the first cooling water.

[0012] According to the present invention, it is possible to prevent clogging of the circulation path of the cooling water that cools the gas containing dust.

[0013] FIG. 1 is a diagram showing the configuration of a waste treatment apparatus according to an embodiment.

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the embodiments described below. Note that the drawings are schematic, and the dimensional relationships between elements may differ from the actual ones.

[0015] 1 is a diagram showing the configuration of a waste treatment device 1 according to an embodiment of the present invention. The waste treatment device 1 is an incineration facility that uses a gasification and reforming method in which waste W is combusted and pyrolyzed to gasify it, and this gas is then reformed at high temperatures to recover it as fuel gas or chemical raw material gas.

[0016] The pit 10 is a facility for storing waste W dumped from a vehicle (not shown). The crane 11 is a crane that stirs and moves the waste W stored in the pit 10. The waste W stored in the pit 10 is grabbed by the crane 11 and dumped into the dump section 13.

[0017] The input section 13 has an opening / closing door 15. The opening / closing door 15 opens and closes an input port 201a (described later) by a drive device (not shown). When the opening / closing door 15 is open, it allows the waste W dropped from the crane 11 to pass downward, and when closed, it blocks the waste W.

[0018] The compression device 20 is a device that compresses the waste W and is provided below the input section 13. The compression device 20 has a cylindrical casing 201. The compression device 20 also has a piston 202 that reciprocates inside the casing 201 and a plate-shaped opening / closing section 203 that moves up and down to open and close the cylindrical opening of the casing 201. The casing 201 is provided with an input port 201a through which the waste W is input. The waste W input into the input section 13 by the crane 11 enters the inside of the casing 201 through the input port 201a. In the compression device 20, the piston 202 moves toward the opening / closing section 203 while the opening / closing section 203 is lowered to block the opening of the casing 201. The waste W is sandwiched between the piston 202 and the opening / closing section 203 as it moves toward the opening / closing section 203, compressed, and molded into a waste block P.

[0019] A heating furnace 70 is provided between the compression device 20 and the gasification and melting furnace 30. One end of the heating furnace 70 is connected to the compression device 20, and the other end is connected to the gasification and melting furnace 30. The heating furnace 70 is externally heated and heats the waste blocks P supplied from the compression device 20 internally. The heated waste blocks P are thermally decomposed by the heat, which evaporates moisture and generates volatile matter. The heated waste blocks P are further thermally decomposed by radiant heat from the gasification and melting furnace 30. The waste blocks P heated in the heating furnace 70 are pushed by the waste blocks P sent from the compression device 20 and sent to the gasification and melting furnace 30. The upper wall of the heating furnace 70 is inclined upward toward the gasification and melting furnace 30, creating a large internal space. Because the internal space expands toward the gasification and melting furnace 30, a space is formed above the waste blocks P, allowing moisture evaporated from the waste blocks P to be released.

[0020] The gasification melting furnace 30 is a positive-pressure furnace and includes a vertically disposed reaction section 31 and a horizontally disposed homogenization section 32. Waste W supplied to the gasification melting furnace 30 is deposited in the lower part of the reaction section 31. High-concentration oxygen is blown into the lower part of the reaction section 31 from an oxygen supply section 40, which generates oxygen. This high-concentration oxygen reacts with carbon in the pyrolyzed waste W, melting the metal and inorganic components in the waste W. This melt flows from the reaction section 31 to the homogenization section 32, where trace amounts of carbon are gasified. In the homogenization section 32, the metal melt (metal) accumulates below the inorganic melt (slag) due to its high density. The metal melt and inorganic melt continuously flow down to the water granulation section 60, where they are cooled and solidified. The cooled and solidified mixture is separated into slag and metal using a magnetic separator.

[0021] The gas generated in the gasification and melting furnace 30 and the gas generated in the heating furnace 70 are retained in the upper part of the reaction section 31 at approximately 1200°C for 2 seconds or more. Under these conditions, the tar components and dioxins and their precursors in the gas are completely decomposed, and H ２ , CO, CO ２ , H ２ The reformed gas is reformed to a reformed gas containing O as the main component.

[0022] One end of a gas duct 33 is connected to the upper end of the reaction section 31, which discharges the reformed gas generated in the reaction section 31 to the outside of the gasification and melting furnace 30. The other end of the gas duct 33 is connected to a cooling and cleaning system 2 that cools and cleans the reformed gas, and the reformed gas that has passed through the gas duct 33 flows into the cooling and cleaning system 2.

[0023] The cooling and cleaning system 2 includes a cooling device 50, a cleaning device 51, a settling tank 52, and a heat exchanger 53. The other end of the gas duct 33 is connected to the cooling device 50 for cooling the reformed gas, and the reformed gas that has passed through the gas duct 33 first flows to the cooling device 50. The cooling device 50 cools the reformed gas with first cooling water 90 that is supplied from a pipe connecting the cooling device 50, the settling tank 52, and the cleaning device 51 and sprayed from the top. The step of cooling the reformed gas with the first cooling water 90 in the cooling device 50 is an example of a cooling step. The temperature of the first cooling water 90 sprayed onto the reformed gas is, for example, 70°C to 99°C. Note that the temperature of the first cooling water 90 sprayed onto the reformed gas may be greater than 99°C and less than 100°C. The first cooling water 90 sprayed from the top of the cooling device 50 comes into contact with the reformed gas. When the first cooling water 90 at this temperature comes into contact with the reformed gas at around 1200°C, the thermal energy of the high-temperature gas evaporates the first cooling water 90, and the reformed gas is rapidly cooled by the heat of vaporization to, for example, 80°C or higher, for example, in the range of 80°C to 99°C. The temperature of the rapidly cooled reformed gas may be greater than 99°C and less than 100°C. Furthermore, some of the fine dust particles and solid matter such as garbage contained in the reformed gas that flies from the gasification and melting furnace 30 are contained in the first cooling water 90 and fall. The first cooling water 90 that falls in the cooling device 50 is sent to the settling tank 52. The temperature of the first cooling water 90 sent to the settling tank 52 is, for example, 80°C to 99°C. The temperature of the first cooling water 90 sent to the settling tank 52 may be greater than 99°C and less than 100°C. The reformed gas cooled by the cooling device 50, including the vapor of the evaporated first cooling water, is sent to the cleaning device 51. The temperature of the reformed gas sent to the cleaning device 51 is 80° C. or higher, for example, in the range of 80° C. to 99° C. The temperature of the reformed gas sent to the cleaning device 51 may be higher than 99° C. and lower than 100° C.

[0024] The settling tank 52 stores the first cooling water 90 used to cool the reformed gas and separates by settling dust and solids contained in the first cooling water 90. The first cooling water 90 from which the solids have been separated in the settling tank 52 is sent again to the top of the cooling device 50 by a pump (not shown) and sprayed onto the reformed gas. A portion of the first cooling water 90 from which the solids have been separated in the settling tank 52 is sent to the water treatment device 57. Note that, because the temperature of the first cooling water 90 sent to the settling tank 52 is 80°C or higher, the settling tank 52 is preferably made of a material that is highly corrosion-resistant and heat-resistant.

[0025] The water treatment device 57 removes metal hydroxides and calcium carbonate from the cooling water sent to it. The cooling water treated by the water treatment device 57 is sent to the salt production device 58. The salt production device 58 removes mixed salt from the cooling water sent from the water treatment device 57. The water from which the mixed salt has been removed is reused, for example, as cooling water.

[0026] The scrubbing device 51 is cooled by a heat exchanger 53, and second cooling water 91, supplied from a pipe connecting the heat exchanger 53 and the scrubbing device 51, is sprayed onto the reformed gas sent from the cooling device 50 to scrub and cool the reformed gas. The temperature of the reformed gas cooled by the scrubbing device 51 is, for example, 50°C to 80°C. The heat exchanger 53 is a device that cools the second cooling water 91, and cools the second cooling water 91, for example, to 30°C to 75°C. The fine particles of the reformed gas sent to the scrubbing device 51 come into contact with the second cooling water 91 as the reformed gas is cooled by the second cooling water 91 and fall together with the second cooling water 91. Furthermore, in the scrubbing device 51, water vapor contained in the reformed gas condenses as the reformed gas is cooled, causing dust in the reformed gas to fall together with the condensed water, and the dust is removed from the reformed gas. The reformed gas cleaned by the scrubbing device 51 is sent to the alkaline scrubbing device 54. The temperature of the reformed gas sent to the alkaline cleaning device 54 is, for example, 50°C to 80°C. A portion of the second cooling water 91 sprayed into the cleaning device 51 and dropped down merges with the first cooling water 90 discharged from the settling tank 52. Dust contained in this merged second cooling water 91 is settled and separated in the settling tank 52. Note that, since the second cooling water 91 contains fine dust particles, the heat exchanger 53 may be periodically maintained and the second cooling water 91 may be periodically replaced.

[0027] The alkaline washing device 54 washes the reformed gas washed in the washing device 51 with alkaline washing water to remove hydrogen chloride and hydrogen fluoride. The reformed gas washed in the alkaline washing device 54 is sent to the desulfurization device 55. The desulfurization device 55 removes hydrogen sulfide from the reformed gas sent from the alkaline washing device 54. The reformed gas from which hydrogen sulfide has been removed in the desulfurization device 55 is sent to the dehumidification device 56. The dehumidification device 56 removes moisture from the reformed gas sent from the desulfurization device 55.

[0028] According to this embodiment, the first cooling water 90 does not pass through a heat exchanger or an auto-strainer, so it is possible to prevent a decrease in the flow rate of the first cooling water 90 injected into the reformed gas. Furthermore, the first cooling water 90 sent to the settling tank 52 contains some of the dust particles and debris contained in the reformed gas. However, these are removed in the settling tank 52, which prevents blockage of the circulation path of the first cooling water 90. Furthermore, in the present invention, most of the dust contained in the reformed gas is sent to the cleaning device 51 together with the vapor of the evaporated first cooling water 90, which reduces the amount of dust that falls with the first cooling water 90, thereby preventing scum from forming in the cooling device 50. Furthermore, in the present invention, the water vapor contained in the reformed gas condenses during the process of cooling the reformed gas in the cleaning device 51, causing the dust in the reformed gas to fall together with the condensed water, thereby removing the dust from the reformed gas.

[0029] [Modifications] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and can be implemented in various other forms. For example, the above-described embodiments may be modified as follows to implement the present invention. The above-described embodiments and the following modifications may be combined with each other. The present invention also includes configurations in which the components of the above-described embodiments and modifications are appropriately combined. Furthermore, further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspects of the present invention are not limited to the above-described embodiments and modifications, and various modifications are possible.

[0030] In the present invention, the second cooling water 91 discharged from the cleaning device 51 and joined with the first cooling water 90 may be sent to the settling tank 52 .

[0031] REFERENCE SIGNS LIST 1 waste treatment device 13 input section 15 open / close door 20 compression device 30 gasification melting furnace 50 cooling device 51 cleaning device 52 sedimentation tank 53 heat exchanger 90 first cooling water 91 second cooling water

Claims

1. A cooling and washing system comprising: a cooling device that injects first cooling water into the reformed gas discharged from a gasification and melting furnace, evaporates the first cooling water, and cools the reformed gas; a sedimentation tank that stores the first cooling water discharged from the cooling device and separates solids contained in the first cooling water; a washing device that injects second cooling water into the reformed gas cooled and discharged by the cooling device, condenses water vapor contained in the reformed gas, and cools and washes the reformed gas; and a heat exchanger that cools the second cooling water discharged from the washing device. The first cooling water from which the solids have been separated in the sedimentation tank is sent to the cooling device and injected into the reformed gas. A part of the second cooling water injected into the reformed gas by the washing device merges with the first cooling water.

2. The cooling and washing system according to claim 1, wherein the temperature of the reformed gas cooled by the first cooling water in the cooling device is 80°C or higher.

3. The cooling and washing system according to claim 1, wherein the temperature of the first cooling water injected into the reformed gas is 70°C or higher.

4. The cooling and washing system according to claim 1, wherein the temperature of the second cooling water injected into the reformed gas is 30°C or higher and 75°C or lower.

5. The cooling and washing system according to claim 1, wherein the temperature of the reformed gas cooled by the washing device is 50°C or higher and 80°C or lower.

6. A cooling and washing method comprising: a cooling step of injecting first cooling water into the reformed gas discharged from a gasification and melting furnace in a cooling device, evaporating the first cooling water, and cooling the reformed gas; a separation step of separating solids contained in the first cooling water in a sedimentation tank that stores the first cooling water discharged from the cooling device; a washing step of injecting second cooling water into the reformed gas cooled and discharged by the cooling device in a washing device, condensing water vapor contained in the reformed gas, and cooling and washing the reformed gas; and a heat exchange step of cooling the second cooling water discharged from the washing device with a heat exchanger. The first cooling water from which the solids have been separated in the sedimentation tank is sent to the cooling device and injected into the reformed gas. A part of the second cooling water injected into the reformed gas by the washing device merges with the first cooling water.

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