JP7049673B2 - Recycling system and preheating method of processing unit in resource recycling system - Google Patents

Description

The present invention provides an invention relating to a resource recycling system that carbonizes and vaporizes waste by superheated steam and recycles it, and a method for preheating a treatment unit in the system, which is particularly suitable for preheating operation.

The treatment device that carbonizes the waste with superheated steam puts the waste into the treatment tank from the inlet, seals the treatment tank and fills it with superheated steam, and carbonizes the waste in a low oxygen state. In such a batch-type processing apparatus, after carbonization, the material is cooled to take out carbonized material, and then the next waste is put into the treatment tank to keep the processing tank in a low oxygen state, and the carbonization process is repeated. In the batch type, the treatment tank is preheated every time the waste is put in, which causes a problem of inefficiency.

Therefore, in the carbonization treatment apparatus as shown in Patent Document 1, a transfer conveyor is provided in the carbonization processing furnace, and the organic matter is carbonized while being conveyed by the transfer conveyor, so that the organic matter can be continuously supplied and processed. ..

Re-table 2013/011555

The continuous type as in Patent Document 1 improves the efficiency in the carbonization processing operation, but the size of the processing tank (carbonization processing furnace) becomes larger than that of the batch type due to the transport space. Therefore, the preheating operation, which is one of the startup operations, takes more than half a day to raise the temperature of the treatment tank to a temperature at which the waste can be processed.

Further, where improvement in the efficiency of the preheating operation is desired, there are some that improve the preheating operation by using the treatment flow path, but in this case, the waste air passage is made a long flow path or a filtration process is generated. The loss increased, and it was not possible to improve efficiency by capturing only the preheating operation.

Therefore, there has been a demand for a resource recovery system that can concentrate on preheating operation to improve efficiency.

The resource recycling system of the present invention is a resource recycling system that carbonizes and vaporizes waste by superheated steam, and includes a boiler that generates steam and a superheated steam generator that heats the steam generated by the boiler to generate superheated steam. , A supply path that directly connects the boiler and the superheated steam generating section, and a processing section that carbonizes the waste by the superheated steam generated by the superheated steam generating section, and the used steam that has passed through the processing section. The steam recirculation section is provided with a steam recirculation section having an upstream end opened in the processing section, and the steam recirculation section is a negative pressure type that sucks used steam from the processing section through the recirculation path. It is characterized by being composed of an ejector.

Further, it is preferable that the used steam has a higher temperature than the steam from the boiler.

Further, the processing unit is opened at a position different from the reflux path and has an exhaust gas that independently discharges the exhaust gas, and the downstream end of the exhaust gas is connected to a gas filtration unit that filters the exhaust gas in a gaseous state. Is preferable.

Further, the processing unit is a container-shaped processing tank, and the superheated steam generating unit arranges a pipe heater having a downward discharge hole on the ceiling of the processing tank and discharges superheated steam from the discharge hole. The treatment tank has a supply unit on one side that allows charging from the ceiling, and a solid discharge unit that is on one side and allows discharge from the bottom, and is a return path. It is preferable that the upstream end of the solid is formed on the other side of the solid discharge portion, which is different from the position of the solid discharge portion, and is formed on the bottom or the wall portion of the side surface close to the bottom.

Further, it is preferable that the pipe heater, which is the superheated steam generating portion, is formed of an Inconel alloy and is of an electric heating type.

Further, the treatment tank has a transport path leading from the supply section to the solid discharge section, and the transport path forms a plurality of conveyors from one side to the other in the vertical direction to generate waste. It is preferable that continuous treatment of carbonization and vaporization while continuously supplying and transporting is possible.

The waste is preferably any of waste plastic, garbage, paper waste, wood waste, fiber waste, vegetable residue, crop residue, food residue, and waste rubber.

Further, in the preheating method of the present invention, waste of any one of waste plastic, dust, paper waste, wood waste, fiber waste, vegetable residue, crop residue, food residue, and waste rubber is carbonized and vaporized by superheated steam as a resource. A method for preheating a treatment unit that carbonizes waste in a system, wherein the steam generated by the boiler is formed on the ceiling portion of the treatment unit through a supply path that directly connects the boiler and the superheated steam generation unit. It is sent to the steam generation unit, and the superheated steam generated by heating with an electric heating type pipe heater in the superheated steam generation unit is ejected from the discharge hole facing downward of the pipe heater to heat the processing unit, and the processing unit is heated. From the upstream end of the return path formed at the bottom or near the bottom of the boiler, used steam, which is hotter than the steam generated by the boiler, is returned to the supply path through a negative pressure ejector, and after the preheating operation is completed. It is characterized in that the check valve is closed to shut off the return of steam before the processing operation.

According to the present invention, superheated steam (used steam) whose temperature has dropped by preheating the treatment tank of the treatment unit can be sucked from the ejector by steam from the boiler, mixed with this steam, and reused as a raw material for superheated steam. , The time of preheating operation can be significantly shortened. Since no waste is placed in the treatment tank during the preheating operation, exhaust gas derived from the waste is not generated, and only used steam can be taken out from the treatment unit without passing through a filtration means. The preheating time can be efficiently shortened without adding a new power source or going through redundant flow paths and processes.

In addition, the superheated steam generating part of the processing part is arranged on the ceiling part, and there are a plurality of parts to be conveyed by the conveyor in the treatment tank, and a reflux path is formed at the bottom on the side different from the solid discharge part to overheat. The recirculation path will be located at the position farthest from the steam generation part and the solid discharge part, and not only will it be placed at the position that has the least effect on the treatment, but it will also recirculate from the position where the temperature is most likely to drop. The efficiency of preheating operation can be effectively increased. Further, the entire device can be made compact by using a pipe heater.

It is a conceptual diagram of the resource recovery system which concerns on embodiment of this invention. It is a conceptual diagram by the front view inside the processing tank. FIG. 2 is a conceptual diagram of the ceiling portion shown in FIG. 2 in a plan view. It is a side view of FIG. It is a flow path diagram of a steam recirculation part.

Embodiments of the present invention will be described in detail with reference to the drawings. In the resource recycling system of the present embodiment, waste is carbonized and vaporized by superheated steam to recover carbonized substances and oils for recycling. As the waste, waste plastic, garbage, paper waste, wood waste, fiber waste, vegetable residue, crop residue, food residue, waste rubber and other waste containing organic compounds that can obtain high-quality oil (organic waste) are preferable. Carbonization and vaporization occur simultaneously or in parallel.

As shown in FIG. 1, the resource recovery system includes a water supply unit 1, a boiler 2, a superheated steam generating unit 3, a processing unit 4 including a processing tank 5, a steam recirculation unit 8, a solid discharge unit 9, and a solid discharge unit 9. It includes a gas recovery unit 10, a flow path connecting each unit, and a control unit such as a computer and a controller. The front of the paper in FIG. 2 will be described as the front, the back of the paper as the rear, the upper part of the paper as the upper side, and the lower part of the paper as the lower side.

The water supply unit 1 supplies water from the outside such as tap water to the boiler 2 and the gas recovery unit 10. The water supply unit 1 has a water softening unit 1a between the water supply unit 1 and the boiler 2, softens the water and supplies it to the boiler 2. The boiler 2 heats the water from the water supply unit 1 to generate steam (saturated steam), and supplies this steam to the superheated steam generation unit 3 via the supply path 11. The boiler 2 comprises, for example, an electric boiler. The boiler 2 may be of a combustion type or the like as long as it can generate steam.

The superheated steam generating unit 3 generates superheated steam from the supplied steam and supplies it into the treatment tank 5. As shown in FIGS. 2 to 4, the superheated steam generating unit 3 includes a pipe heater 3a provided on the ceiling portion 5a of the processing tank 5, and steam is introduced into the pipe heater 3a generated by energization to generate the steam. Superheated steam is generated from the ceiling and supplied to the treatment tank 5.

The pipe heater 3a is composed of, for example, two inconel pipes arranged symmetrically side by side. The Inconel pipe is made of an Inconel alloy pipe material, which is an alloy containing nickel, carbon, iron, and chromium, has strong heat resistance, and can withstand long-term use. Further, even at the time of preheating of the present embodiment, it is compatible with the present embodiment because it can withstand even if steam that is refluxed in the preheating stage and sequentially has different temperatures is sent through the ejector 13.

The pipe heater 3a has a plurality of discharge ports facing downward at equal intervals and is laid on the ceiling portion 5a. It is preferable that the pipe heater 3a is bent and curved and spread on the ceiling portion 5a. In the present embodiment, the pipe heater 3a is inserted from the central inner side of the ceiling portion 5a, and the vicinity of the inner side edge of the ceiling portion 5a is divided into left and right branches. After passing through the edges on both sides, it curves further to the opposite side, passes through the central part of each, passes through the front side of the center, and has a substantially R-shaped shape leading to the back side of the center. The form is not limited to this, and may be substantially S-shaped, or the ceiling portion 5a may be spread in a zigzag pattern.

The superheated steam is discharged from the pipe heater 3a to the outer peripheral side and the center of the treatment tank 5, the temperature inside the treatment tank 5 is raised to maintain a high temperature state, and the inside of the treatment tank 5 is filled with low oxygen while expelling air. Make it a state (including anoxic state). This air is discharged from the exhaust passage 7 of the processing unit 4 and discharged to the outside via the gas recovery unit 10. The exhaust passage 7 has a damper (not shown), and the internal pressure of the processing tank 5 is maintained at a constant pressure condition (normal pressure) by opening and closing the damper.

The processing unit 4 is composed of a rectangular processing tank 5 that is long on the left and right and short on the top and bottom when viewed from the front. The inside of the treatment tank 5 is composed of a ceiling portion 5a having a space for arranging the superheated steam generating portion 3, a wall portion 5b made of a heat insulating material, and a boat-shaped bottom portion 5c inclined downward from both sides in the front-rear direction to the center (FIG. 4). The treatment unit 4 performs a preheating operation for raising the temperature inside the treatment tank 5 with superheated steam, and then performs a treatment operation for supplying waste into the treatment tank 5 and carbonizing and vaporizing it with the filled superheated steam. The waste subjected to this treatment operation is decomposed into carbides (solid treated products) and exhaust gas (gas treated products).

The preheating operation is an operation in which the treatment tank 5 is filled with superheated steam from the superheated steam generator 3 to preheat to a predetermined temperature or higher, and the inside of the treatment tank 5 is kept in a low oxygen state and a high temperature state of 400 ° C. or higher. This completes the operation and shifts to the processing operation. The treatment operation is an operation in which superheated steam is continuously introduced into the treatment tank 5 from the preheating operation, and waste is supplied to carbonize and vaporize while maintaining a low oxygen and high temperature state.

The steam recirculation unit 8 recirculates the superheated steam (used steam) whose temperature has been lowered by using it for preheating from the treatment tank 5 to the supply path 11. The steam recirculation unit 8 functions only during the preheating operation, and more specifically, it functions in a hypoxic state. Specifically, the steam return path 8 is closed by the check valve 14 until the inside of the processing unit 4 reaches a predetermined temperature and becomes a hypoxic state, and after the temperature reaches a predetermined temperature, the check valve 14 is opened and used. The finished steam is returned to the ejector 13. The operation of the check valve 14 causes the used steam to recirculate at a temperature higher than that of the steam generated by the boiler 2.

The steam recirculation unit 8 does not require a power source such as a pump, and the used steam is made to flow by the steam of the boiler 2. The steam recirculation unit 8 is composed of a recirculation path 12 connecting the supply path 11 and the treatment tank 5, and an ejector 13 provided in the middle of the supply path 11, and the recirculation path 12 is made a negative pressure by the ejector 13 to make the used steam. Is refluxed and supplied to the superheated steam generating unit 3. In the present embodiment, the steam recirculation section 8 is composed of only a pipe-shaped ring flow path 12 having a check valve 14 arranged in the middle and connected to the ejector 13, and blocks the inside of the ring flow path 12 such as a filtration device. No members are placed.

The return passage 12 has a check valve 14 in the middle, and the downstream end communicates with the suction portion 13c of the ejector 13. As shown in FIGS. 2 to 4, the return passage 12 has an upstream end opened at a position different from that of the exhaust passage 7 of the treatment tank 5, and is provided independently of the exhaust passage 7. The upstream end of the return path 12 is opened, for example, in the center of the lower left end of the wall portion 5b in the front-rear direction, and the inclination of the bottom portion 5c facilitates suction of used steam. Moreover, it is located at the lowest position and is arranged diagonally or at a position opposite to the exhaust passage 7 and the solid discharge portion 9 (on the other side), and may have the lowest temperature in the processing portion 4. It is a position and is opened at a position where exhaust and exhaust are not affected.

As shown in FIG. 5, in the ejector 13, the side where steam (heated steam) flows in from the boiler 2 is the nozzle side 13a, and the side where the heated steam is discharged to the superheated steam generating unit 3 is the throat side 13b. It has a suction portion 13c connected to the return path 12. The ejector 13 sucks the used steam from the suction unit 13c by the inflow of the heated steam from the nozzle side 13a, and supplies the mixed steam in which the heated steam and the used steam are mixed to the downstream side of the supply path 11 (superheated steam generating unit 3). ).

In this embodiment, for example, the driving flow rate of steam and the suction flow rate of used steam are set to 50 kg / h, the heated steam is set to about 130 ° C, and the used steam in the initial stage of preheating operation (initial stage of reflux start) is set to about 150 ° C. The mixed steam is set to about 137 ° C. The driving pressure of the heated steam is 0.196 MPa, the suction pressure of the used steam is −10 kPa, and the discharge pressure of the mixed steam is 10 kPa. The temperature of the used steam gradually rises as the reflux (preheating operation) continues.

The superheated steam generating unit 3 can efficiently generate superheated steam by the mixed steam having a higher temperature than the heated steam, and the preheating time of the processing unit 4 can be shortened. For example, in the case of the treatment tank 5 of about 7.6 kL, the preheating time conventionally required for half a day can be shortened to about 2 hours.

The processing unit 4 has a supply unit 6 for supplying waste into the processing tank 5, a transport unit 15 for transporting the waste in the processing tank 5 until carbonization and vaporization are completed, and a processing tank as equipment for processing operation. It is provided with an exhaust passage 7 for discharging exhaust gas from 5.

The supply unit 6 is located on one side of the ceiling portion 5a of the treatment tank 5, and wastes are discharged from the hopper 6a through the input mechanism 6b including the rotary valve from the drop port 6c into the treatment tank 5. It is possible to supply continuously (automatically) by dropping it on the ceiling. The drop port 6c has an on-off valve 6d that opens according to the weight of the waste, and automatically opens and closes according to the waste.

Further, the supply unit 6 has an introduction port 6e downstream of the charging mechanism 6b, and the introduction port 6e enables waste to be introduced toward the dropping port 6c without going through the charging mechanism 6b. The introduction port 6e has a lid 6f that opens and closes manually, and large-sized waste that cannot pass through the charging mechanism 6b for manual supply can be dropped into the treatment tank 5. The charging mechanism 6b and the introduction port 6e are located on the same side of the ceiling portion 5a as the supply section 6, and are connected to the inside of the processing tank 5 by one dropping port 6c (opening / closing valve 6d).

The transport unit 15 is composed of belt conveyors 16a and 16b arranged vertically in two stages in the processing tank 5, and suppresses the left-right length of the processing tank 5, the total length of the pipe heater 3a, and the number of installations. The upper and lower belt conveyors 16a and 16b are formed of a metal mesh belt, and waste is arranged and conveyed on the upper surface. The upper and lower belt conveyors 16a and 16b are arranged in parallel with the horizontal direction (horizontal direction) as the transport direction, and the transport directions (arrows A and B in FIG. 2) are opposite to each other.

Waste is supplied from the supply unit 6 to the upstream end (right end) of the upper belt conveyor 16a, and the waste is conveyed from the right to the left end (downstream end). The waste being processed that reaches the downstream end falls to the upstream end (left end) of the lower belt conveyor 16b by the guide plate 18a. Further, the guide plate 18a is arranged above the upstream end (opening) of the return path 12 and is positioned so that superheated steam bypasses and flows into the return path 12, improving the efficiency of the preheating operation.

The lower belt conveyor 16b is arranged above the opening of the return path 12. The lower belt conveyor 16b conveys the waste that has fallen to its upstream end and is supplied to the downstream end (right end), and the carbonized material that remains after being sufficiently carbonized and vaporized is dropped onto the solid discharge unit 9 by the guide unit 18b. And discharge.

The solid discharge portion 9 communicates with the right end of the bottom portion 5c of the treatment tank 5. The solid discharge unit 9 is composed of a screw feeder, and is cooled to such an extent that it does not ignite even if it is exposed to the outside air while transporting the carbide, so that the carbide can be taken out to the outside.

The gas recovery unit 10 recovers the exhaust gas composed of the gas generated from the waste in the treatment tank 5 and the superheated steam used for the treatment operation, and separates the exhaust gas into oil, water, residue and the like. The gas recovery unit 10 includes a gas filtration unit 19 that filters exhaust gas in a gaseous state, a heat exchange unit 20 that cools the filtered exhaust gas and separates gas and liquid, and an oil-water separation unit that further separates the separated liquid into oil and water. The unit 21 includes a deodorizing device 22 for deodorizing the separated gas, and a wastewater filtration unit 23.

The gas filtration unit 19 is of a cyclone type, the exhaust gas is filtered by a centrifugal force and a filter, the filtered exhaust gas is introduced into the heat exchange unit 20 in a gaseous state, and the residue is discharged to the outside. The filter is made of activated carbon, iron oxide, stainless wool, slaked lime, etc., and removes impurities in oil such as chlorine, sulfur, and tar as residual impurities.

A filtered exhaust gas (gas state) is introduced into the heat exchange unit 20, and this exhaust gas is cooled by heat exchange to separate a liquid (oil-water mixture) consisting of oil and water and a residual gas (non-condensable gas). ing. The heat exchange unit 20 supplies the oil-water mixture to the oil-water separation unit 21 and introduces the non-condensable gas into the deodorizing device 22. The heat-exchanged water (hot water) is cooled by the cooling unit 20a and reused.

The oil-water separation unit 21 separates the oil-water mixture into oil and water. A part of the separated oil can be reused as a useful substance equivalent to high-purity heavy oil (so-called "A heavy oil"). Further, the separated water is filtered by the wastewater filtration unit 23 and discharged to the outside as wastewater.

The deodorizing device 22 deodorizes the non-condensed gas using water and discharges it to the outside as harmless exhaust gas, and the used water is filtered by the wastewater filtration unit 23 to be discharged.

2 ... Boiler, 3 ... Superheated steam generator, 3a ... Pipe heater, 4 ... Processing unit, 5 ... Processing tank, 7 ... Exhaust passage, 8 ... Steam recirculation unit, 9 ... Solid discharge unit, 11 ... Supply passage, 12 ... Circulation path, 13 ... ejector, 15 ... transport section, 19 ... gas filtration section.

Claims (8)

A resource recycling system that carbonizes and vaporizes waste with superheated steam.
It is generated by a boiler that generates steam, a superheated steam generator that heats the steam generated by the boiler to generate superheated steam, a supply path that directly connects the boiler and the superheated steam generator, and the superheated steam generator. It has a processing unit that carbonizes the waste with superheated steam.
It is provided with a steam recirculation unit that recirculates the used steam that has passed through the processing unit to the supply path.
The steam recirculation unit is a resource recycling system including a recirculation path having an upstream end opened in the processing unit and a negative pressure type ejector that sucks used steam from the processing unit through the recirculation path. The resource recycling system according to claim 1, wherein the used steam has a higher temperature than the steam from the boiler. The processing unit opens at a position different from the return path and has an exhaust gas that discharges exhaust gas independently, and the downstream end of the exhaust gas is connected to a gas filtration unit that filters the exhaust gas in a gaseous state. The resource recycling system according to claim 1 or 2. The processing unit is a container-shaped processing tank, and the superheated steam generating unit arranges a pipe heater having a downward discharge hole on the ceiling of the processing tank and discharges superheated steam from the discharge hole.
The treatment tank has a supply unit on one side that allows charging from the ceiling, and a solid discharge unit on one side that allows discharge from the bottom.
Any of claims 1, 2 or 3, wherein the upstream end of the return path is on the other side, which is different from the position of the solid discharge portion, and is formed on the bottom or the wall portion of the side surface close to the bottom. Recycling system described in Crab. The resource recycling system according to claim 4, wherein the pipe heater, which is a superheated steam generating unit, is formed of an Inconel alloy and is of an electric heating type. The treatment tank has a transport path leading from the supply section to the solid discharge section.
The transport path is characterized in that a plurality of conveyors extending from one side to the other are formed up and down, and continuous processing of carbonization and vaporization while continuously supplying and transporting waste is possible. The resource recycling system according to claim 4 or 5. The resource according to any one of claims 1 to 6, wherein the waste is any one of waste plastic, garbage, paper waste, wood waste, fiber waste, vegetable residue, crop residue, food residue, and waste rubber. System. A process of carbonizing the waste in a resource recycling system that carbonizes and vaporizes waste of any of waste plastic, garbage, paper waste, wood waste, fiber waste, plant residue, crop residue, food residue, and waste rubber by superheated steam. It ’s a method of preheating the part.
The steam generated by the boiler is sent to the superheated steam generating section formed on the ceiling of the processing section through a supply path that directly connects the boiler and the superheated steam generating section.
The superheated steam generated by heating with an electric heating type pipe heater in the superheated steam generating part is ejected from a discharge hole facing downward of the pipe heater to heat the processing part.
From the upstream end of the return path formed at the bottom of the processing section or at a position close to the bottom, used steam having a temperature higher than that of the steam generated by the boiler is returned to the supply path through a negative pressure type ejector.
A method for preheating a processing unit in a resource recycling system, which comprises closing a check valve to shut off the return of steam after the preheating operation is completed and before the processing operation.

Images