JP2011031226A - Waste desalination method and waste desalination apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively crush and desalinize mixed waste containing organic chlorine by heating the mixed waste without remarkably lowering the calorific value of recycled solid fuel and without providing a high performance or large sized heating device to heat the atmosphere of a reaction vessel in the vessel itself. <P>SOLUTION: The waste and a compound of a metal element which causes a reaction with organic chlorine in the waste to produce an inorganic salt are introduced into a reactor and saturated steam having prescribed pressure of 2.0-3.0 MPa is supplied to the reactor to keep the temperature of the reactor to the temperature of the saturated steam. The waste and the compound are stirred in this state to thermally decompose the mixed waste to produce the inorganic salt by the reaction of the organic chlorine with the metal element. The steam in the reactor is led to outside of the reactor and the solid portion containing the inorganic salt remaining in the reactor is discharged outside of the reactor as the recycled solid fuel. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a waste desalination method and a waste desalination apparatus for mixed waste. More specifically, the present invention relates to organic matter in waste when recycled mixed waste by heat treatment with steam. The present invention relates to a waste desalting method and a waste desalting apparatus for converting chlorine into inorganic chlorine to make it harmless.

  Mixing waste such as garbage, food waste, agricultural waste, forestry waste, and medical waste in a heating container, heating and stirring, reducing the volume of waste by hydrothermal reaction, miniaturizing Alternatively, a hydrothermal waste treatment apparatus that pulverizes is known (Japanese Patent Laid-Open No. 2003-306825).

  After storing such mixed waste in a container and heating (cooking) the waste with high-temperature and high-pressure steam for several tens of minutes, the pressure in the container is released momentarily, and the energy of adiabatic expansion of water A steam explosion (steaming explosion) type waste disposal apparatus that crushes (explodes) a solid component is known (Japanese Patent Laid-Open No. 2003-47409, Japanese Patent No. 3613567).

  Further, there is disclosed a waste fueling device that uses a processing container for treating mixed waste in water and stirs hot water and waste while maintaining the pressure and temperature in the container at high temperature and high pressure. It is described in the issue. This type of fueling apparatus is configured to melt and hydrolyze waste with high-temperature, high-pressure water of 1.55 MPa and 200 ° C. or higher.

  In recent years, techniques such as incineration of mixed waste containing plastics such as PVC (polyvinyl chloride) or solid fuel production have attracted particular attention from the standpoint of reducing environmental impact. Hydrogen chloride (HCl) generated during the combustion of mixed waste containing PVC (polyvinyl chloride), etc. not only causes problems such as corrosion of combustion and incineration equipment, but depending on the operating conditions of the combustion and incineration equipment, There is concern over further problems such as dioxin by-product. Therefore, as described in JP-A-2000-344934, dehydrochlorination treatment (demineralization) in which waste is heated to 300 ° C. or more and melted, and hydrogen chloride is vaporized and separated by thermal decomposition of waste plastics. Treatment or dechlorination treatment), or as described in JP-A-7-305825, a calcium compound is introduced into a combustion furnace together with waste, and hydrogen chloride generated during incineration of the waste is converted into calcium compound Desalination treatment is carried out to make it harmless by reacting with.

JP 2003-306825 A JP 2003-47409 A Japanese Patent No. 3613567 JP 2007-112880 A JP 2000-344934 A Japanese Unexamined Patent Publication No. 7-305825

  Hydrolysis of mixed waste with high-temperature / high-pressure water or saturated steam, explosion of hydrous waste by rapid pressure reduction in the container, or detoxification, pulverization and drying by both hydrolysis and explosion According to the conventional waste treatment apparatus (Patent Documents 1 to 3) that achieves this, it may be possible to produce a regenerated solid fuel having a relatively high calorific value and supply it to an arbitrary combustion apparatus or the like.

  However, in a conventional waste treatment apparatus that produces recycled solid fuel by hydrothermal treatment, steaming or steaming / explosive treatment of waste, normally, high-temperature / high-pressure water at a temperature / pressure of 200 ° C. and 1.6 MPa or less Or, because saturated steam was used, when trying to recycle mixed waste containing waste plastics such as polyvinyl chloride (PVC), organic chlorine in the waste would remain in the solid fuel . For this reason, when regenerated solid fuel is supplied as a fuel to a combustion kiln such as a cement kiln, hydrogen chloride is generated in the furnace, causing problems such as furnace blockage and furnace body corrosion.

  On the other hand, the pressure and temperature in the processing container are maintained at 1.55 MPa and 200 ° C. or higher, and the fueling apparatus is configured to hydrolyze waste with high-temperature and high-pressure hot water (Patent Document 4). According to the present invention, it is considered possible to thermally decompose polyvinyl chloride or the like in the mixed waste to vaporize hydrogen chloride, and discharge the hydrogen chloride together with water vapor to the outside of the system.

  However, in order to maintain the atmosphere in the processing container at such a high temperature and high pressure state, a large amount of heat must be supplied into the container in order to heat the mixed waste and water in the container and maintain the high temperature and high pressure state. For this reason, the processing container requires a high-performance and large-sized heating device for heating the atmosphere in the container, and it is necessary to supply a large amount of electric power or fuel to the heating device in order to operate this kind of heating device. Arise. In addition, when the atmosphere in the container is heated to a temperature exceeding 250 ° C., not only the chlorine in the waste but also useful organic substances contained in the waste are similarly thermally decomposed and vaporized. There is a tendency that the concentration of discharged organic matter increases, which is a factor that greatly reduces the calorific value of the regenerated solid fuel remaining in the container.

  In addition, the desalination method (Patent Document 5) that vaporizes and separates hydrogen chloride by heating and melting mixed waste containing waste plastics such as polyvinyl chloride to a high temperature of 300 ° C. or higher is effective in removing hydrogen chloride. However, it requires a relatively large-scale and high-performance heating / melting device for heating / melting waste. Moreover, since many kinds of mixed waste, such as household waste, contain various substances that are difficult to identify, such mixed waste is uniformly heated and melted by a single heating and melting device. It is extremely difficult to do in reality.

  Furthermore, the desalination method (Patent Document 6) in which a calcium compound is introduced into a combustion furnace together with waste is merely for detoxifying hydrogen chloride generated in the atmosphere in the high temperature furnace during waste incineration. This is not a method that can be applied to a technique for desalinating waste in a pretreatment process before waste incineration or in the process of converting waste into a regenerated fuel.

  The present invention has been made in view of such problems, and the object of the present invention is to provide a high performance or large capacity to heat the atmosphere in the container without greatly reducing the calorific value of the regenerated solid fuel. Without providing a heating device in the form of a reaction vessel itself, a mixed waste demineralization treatment apparatus and desalting apparatus that can heat mixed waste containing organic chlorine to effectively crush and demineralize the waste. It is to provide a salt treatment method.

In order to achieve the above object, the present invention provides a waste desalination method in which a mixed waste containing organic chlorine is thermally decomposed and desalted in a high-temperature and high-pressure container region.
Introducing the waste and a metal element compound that reacts with organic chlorine in the waste to form an inorganic salt into the reactor;
In the state in which saturated steam having a predetermined pressure within a range of 2.0 to 3.0 MPa is supplied into the reactor and the temperature in the reactor is maintained at the temperature of the saturated steam, the waste and the compound Are mixed and stirred to thermally decompose the mixed waste, and react with the organic chlorine and the metal element to produce an inorganic salt,
Waste demineralization characterized in that the water vapor in the reactor is led out of the reactor, and the solid content remaining in the reactor and containing the inorganic salt is led out of the reactor as a regenerated solid fuel. Provide a method.

The present invention also relates to a waste desalination apparatus for desalinating by decomposing mixed waste containing organic chlorine in a high-temperature / high-pressure container region.
A reactor into which the waste is introduced;
An inorganic salt generator supply device for introducing into the reactor a compound of a metal element that reacts with organic chlorine in the waste to generate an inorganic salt;
A steam supply device for supplying saturated steam having a predetermined pressure within a range of 2.0 to 3.0 MPa into the reactor;
A stirring device for mixing and stirring the waste and the compound,
The waste water and the compound are mixed by operating the stirring device in a state where the saturated water vapor is filled in the reactor by the water vapor supply device and the temperature in the reactor is maintained at the temperature of the saturated water vapor. Provide a waste desalination apparatus characterized by stirring.

  According to the above configuration of the present invention, saturated steam having a predetermined pressure in the range of 2.0 to 3.0 MPa is supplied into the reactor, and the temperature in the reactor is maintained at the temperature of the saturated steam for a predetermined time. The The temperature of the saturated steam having a pressure of 2.0 to 3.0 MPa is about 212 to 233 ° C. Therefore, the temperature in the reactor is maintained at a predetermined temperature in the range of about 212 to 233 ° C. for a predetermined time.

  Saturated water vapor in the reactor condenses in contact with the waste. Waste is thermally decomposed by receiving a great amount of latent heat held by water vapor, or hydrolyzed. Since the waste is mainly heated by the latent heat of saturated steam, it is not necessary to provide a high-performance or large-sized heating device for heating the atmosphere in the container in the reaction container itself.

  The temperature in the reactor is controlled to a saturated steam temperature, that is, a predetermined temperature within a range of about 212 to 233 ° C. In this temperature range, the heat of the organic chlorine compound such as polyvinyl chloride (PVC) is controlled. While the decomposition reaction proceeds, it has been found that the thermal decomposition reaction of hydrocarbons or carbon compounds hardly proceeds. That is, only the organic chlorine in the mixed waste is separated as hydrogen chloride, whereas the thermal decomposition of the organic compound and hydrocarbon in the mixed waste does not proceed so much. For this reason, the combustible component held by the mixed waste hardly flows out from the solid component by vaporization or liquefaction, and therefore a solid component having a relatively high calorific value remains in the reactor.

  The present inventor conducted various experiments on the hydrothermal treatment of such mixed waste, and encountered the following facts in the course of the experiment.

(1) When mixed waste such as medical waste containing a relatively small amount of base or basic compound is hydrothermally treated, most of the hydrogen chloride vaporized in the reactor is effectively removed by steam. Can be discharged outside.

(2) When mixed waste containing a relatively large amount of a base or basic compound such as sodium hydroxide or calcium hydroxide is hydrothermally treated, hydrogen chloride released from the waste due to thermal decomposition is separated from the metal element compound in the waste. As a result of reacting and producing a relatively large amount of inorganic salt, it is likely that a situation in which it is difficult to transfer chlorine in waste to the water vapor side as desired.

  In view of such experimental results, the present inventor positively charged a compound of a metal element that reacts with organic chlorine in waste to produce an inorganic salt into the reactor, and this compound is subjected to the above temperature conditions. A configuration in which mixing and stirring are performed together with waste in the presence of saturated steam is employed as described above.

  The metal element of such a compound reacts with hydrogen chloride released by thermal decomposition to produce an inorganic salt in the waste, and remains in the waste as an inorganic salt. In the present invention, “desalting” refers to the conversion of chlorine (organic chlorine) in an organic compound into inorganic salt chlorine (inorganic chlorine) in this way (that is, deorganic chlorine treatment for inorganic chlorination of organic chlorine). Means). Regenerated solid fuel containing inorganic salt is supplied as a combustion fuel to a combustion apparatus such as a heating furnace or a boiler, supplied as a gasification fuel to a gasification furnace or a pyrolysis furnace, or supplied to an oilification apparatus as an oily raw material. Once supplied, the mineralized chlorine is not released into the flue gas unless it is burned in a very high temperature (1400 ° C or higher) combustion atmosphere, and substantially all of it remains in the combustion ash as an incineration residue. Alternatively, it remains in the pyrolysis kettle or the like as an oily residue. Accordingly, by subjecting the organic chlorine to inorganic chlorination according to the present invention, substantially the same effect as that of the conventional desalting treatment can be obtained.

  In the present specification, “organic chlorine” is defined as chlorine in an insoluble organic compound that is not soluble in water, and “inorganic chlorine” is defined as chlorine in a soluble inorganic salt that is soluble in water. .

  According to the waste desalination method and the waste desalination apparatus of the present invention, a high-performance or large-sized heating device is reacted to heat the atmosphere in the container without greatly reducing the calorific value of the regenerated solid fuel. Without providing in the container itself, the mixed waste containing organic chlorine can be heated to effectively crush and demineralize the waste.

1 is a block diagram schematically showing an overall configuration of a waste treatment apparatus for carrying out a desalting method according to a first embodiment of the present invention. FIG. 2 is a block flow diagram schematically showing the structure and operation mode of the waste treatment apparatus shown in FIG. 1, in which the operation process of the waste treatment apparatus is shown in stages. It is a diagram which shows the chlorine content rate of each sample after the hydrothermal treatment obtained as a result of the hydrothermal treatment experiment. It is a diagram which shows the total calorific value of each sample after the hydrothermal treatment obtained as a result of the hydrothermal treatment experiment. It is a block diagram which shows roughly the whole structure of the waste-treatment apparatus for enforcing the desalination method which concerns on 2nd Example of this invention. FIG. 6 is a block flow diagram schematically showing the structure and operation mode of the waste treatment apparatus shown in FIG. 5. It is a block diagram which shows roughly the whole structure of the waste-treatment apparatus for enforcing the desalination method which concerns on 3rd Example of this invention. FIG. 8 is a block flow diagram schematically showing the structure and operation mode of the waste disposal apparatus shown in FIG. 7. FIG. 9 is a block flow diagram schematically showing the structure and operation mode of the waste treatment apparatus shown in FIG. 7, and shows a step subsequent to the step shown in FIG. 8.

  Preferably, the metal element is at least one metal element selected from the group consisting of calcium, magnesium, sodium and potassium, and the compound is an oxide, hydroxide or carbonate of these metal elements.

  According to a preferred embodiment of the present invention, the saturated steam pressure is set to a predetermined pressure in the range of 2.5 to 3.0 MPa, for example 2.8 MPa, and the temperature in the reactor is about 224 to 233. It is set to a temperature in the range of ° C, for example, about 230 ° C.

  In a preferred embodiment of the present invention, a second reactor is further provided, and solids in the reactor (first reactor) are transferred from the first reactor to the second reactor, A drying process is performed in the second reactor. Preferably, air having a temperature corresponding to the outside air temperature or air heated to a predetermined temperature is forcibly ventilated into the first and / or second reactor as drying air. The atmosphere in the reactor is ventilated, and the solid content in the reactor is forcibly dried by passing normal temperature air or warm air.

  Preferably, a control system facility for detecting the temperature or pressure in the first reactor and controlling the supply of saturated water vapor to the first reactor is provided. If desired, this control system equipment further includes a measuring means for measuring the atmosphere (temperature, humidity, etc.) of the drying region (region in the container) in the drying process, and is also configured to control the operation of the drying equipment. Is done.

  The predetermined time (holding time) is set to at least 15 minutes, preferably 30 minutes or more, more preferably 1 hour or more (for example, 90 minutes).

  If desired, the solid content in the first reactor is hydrated, mixed and stirred in the first reactor, or introduced into the mixing and stirring tank to be hydrated and mixed and stirred for a predetermined time. As a result, the solid content is slurried. To do. The inorganic salt remaining in the solid content is eluted in water in the first reactor or the mixing and stirring tank. Preferably, the weight of water to be added is set in the range of 2 to 50 parts by weight with respect to 1 part by weight of the solid content in the reactor. The slurry containing the solid content is introduced into a solid-liquid separation device and separated into solid and liquid. The salt eluted in water is discharged out of the system as an aqueous solution. More preferably, the solid content after the solid-liquid separation is transferred to the second reactor and subjected to a drying treatment. If desired, air at a temperature equivalent to the outside air or air heated to a predetermined temperature is passed through the second reactor as dry air, and the dry air forces the solid content to dry.

  FIG. 1 is a block diagram schematically showing the overall configuration of a waste treatment apparatus for carrying out a desalting method according to a first embodiment of the present invention.

  The waste treatment apparatus includes a first reactor, a second reactor, and a waste water treatment apparatus. Mixed waste containing a relatively large amount of polyvinyl chloride (PVC) is fed into the first reactor, and it reacts with hydrogen chloride as an inorganic salt generator that converts organic chlorine in the waste into inorganic chlorine. Calcium, magnesium, sodium or potassium oxides, hydroxides or carbonates, such as quicklime (CaO), which produce inorganic salts are fed into the first reactor. As described above, in this specification, “organic chlorine” is defined as chlorine in an insoluble organic compound that is not soluble in water, and “inorganic chlorine” is chlorine in a soluble inorganic salt that is soluble in water. Is defined as

  High temperature and high pressure saturated steam is further fed into the first reactor. The first reactor has a temperature detector T and a pressure detector P that detect the temperature and pressure in the container, and the detectors T and P are connected to a control device (control unit) C / U. The control device C / U outputs a control signal to the steam supply source, or controls valves and the like of the steam supply system equipment, whereby the pressure and supply amount (flow rate) of the steam supplied to the first reactor. ) Etc.

  The pressure of the saturated water vapor in the first reactor is set to a predetermined pressure in the range of 2.0 to 3.0 MPa, preferably in the range of 2.5 to 3.0 MPa, for example, 2.8 MPa. The temperature of saturated steam at a pressure of 2.0 to 3.0 MPa is about 212 to 233 ° C., and the temperature of saturated steam at a pressure of 2.5 to 3.0 MPa is about 224 to 233 ° C. Moreover, the temperature of the saturated steam at a pressure of 2.8 MPa is about 230 ° C.

  In the present embodiment, an existing or existing steam generator capable of supplying saturated steam at a predetermined pressure within a range of 2.0 to 3.0 MPa (preferably within a range of 2.5 to 3.0 MPa), for example, The existing steam boiler of the power generation facility or other equivalent existing steam boiler can be suitably used as the steam supply source. If desired, a steam generator capable of supplying saturated steam at such a pressure may be newly installed. In addition, the steam supply equipment that generates and supplies high-pressure steam exceeding 3.0 MPa requires relatively advanced or special technology from the viewpoint of pressure resistance, durability, etc., and is the initial stage of equipment or devices such as steam boilers. Costs (purchase / installation costs, etc.) are considerably increased, but as long as saturated steam with a pressure of 3.0 MPa or less is used, existing or general-purpose equipment can be used as described above. Even if a steam supply system facility is newly installed, it is considered that a steam supply system facility can be installed relatively easily.

  The control device C / U outputs a control signal to the water vapor supply source so as to maintain the pressure and temperature of the saturated water vapor in the first reactor at the pressure and temperature for a predetermined time based on the detection results of the detectors T and P. Alternatively, the steam supply system equipment is controlled. The pressure and temperature holding time in the first reactor is set to at least 15 minutes, preferably 30 minutes or more, and more preferably 1 hour or more.

  The mixed waste to which an inorganic salt generating agent such as quick lime (CaO) is added is mixed and stirred in the first reactor, and comes into contact with the saturated water vapor in the first reactor. The saturated water vapor condenses, and the great latent heat that the water vapor retains is dissipated to the mixed waste. It has been found that in the temperature range of about 212 to 233 ° C., the thermal decomposition reaction of polyvinyl chloride (PVC) proceeds, but the thermal decomposition reaction of hydrocarbons or carbon compounds does not occur. That is, in the temperature range of about 212 to 233 ° C., substantially only organic chlorine in the mixed waste tends to vaporize as hydrogen chloride gas, but thermal decomposition of the organic compound and hydrocarbon in the mixed waste is not so much. Therefore, a large amount of combustible matter retained in the mixed waste does not flow out of the solid content by vaporization or liquefaction, and a relatively high exothermic solid content remains in the first reactor.

An inorganic salt generating agent such as quicklime (CaO) is mixed with the mixed waste in the first reactor. According to the inventor's experiment, when medical waste having a low alkali compound content is heat-treated with steam at about 212 to 233 ° C., a considerable amount of organic chlorine in the waste is released, and hydrogen chloride ( HCl) is transferred to water vapor, but when the waste mixed with an inorganic salt generator such as quick lime (CaO) that reacts with hydrogen chloride to produce an inorganic salt is heat-treated with water vapor at about 212 to 233 ° C., calcium A metal element such as hydrogen chloride reacts with chlorine in hydrogen chloride to produce an inorganic salt such as calcium chloride (CaCl ₂ ). Therefore, the transfer of hydrogen chloride to water vapor is suppressed. Organic chlorine is converted to inorganic chlorine and remains in the waste as an inorganic salt.

  The control device C / U holds the pressure and temperature of the saturated steam in the first reactor for a predetermined time, and then discards the first reactor so that the steam in the first reactor is discharged as waste steam to the waste water treatment device. A steam discharge device (not shown) is controlled, and the waste steam is discharged to the waste water treatment device. The waste steam is condensed and subjected to neutralization in the waste water treatment apparatus, and then drained out of the system through a drain system pipe line (not shown).

  The controller C / U also controls a solid content transfer device (not shown) of the first reactor so that the solid content remaining in the first reactor is transferred to the second reactor. The solid content transferred to the second reactor is subjected to a drying process (or dehydration / drying process) in the second reactor. The solid content after drying is discharged from the second reactor and shipped to an external facility or the like as a regenerated solid fuel containing an inorganic salt, for example, a solid fuel replacing coal. If desired, a part of the regenerated solid fuel is used as a fuel for a steam boiler or the like (not shown) constituting the steam supply source.

  Recycled solid fuel containing inorganic salts is supplied to combustion equipment such as heating furnaces and boilers and undergoes a combustion reaction. Chlorine once mineralized is a combustion exhaust gas unless it is burned in a very high temperature (1400 ° C or higher) combustion atmosphere. It is not released in, and substantially all of it remains in the combustion ash as an incineration residue. This eliminates problems such as furnace blockage, furnace body corrosion, and generation of harmful gases. That is, by chlorinating organic chlorine as described above, substantially the same effect as that obtained by the conventional desalting treatment can be obtained. In addition, the regenerated solid fuel may be supplied to the liquefaction apparatus as an oily raw material. In this case, the inorganic salt contained in the regenerated solid fuel remains in the pyrolysis kettle or the like as an oily residue.

  FIG. 2 is a block flow diagram schematically showing the structure and operation mode of the waste disposal apparatus shown in FIG. FIG. 2 shows a step-by-step operation process of the waste treatment apparatus.

  As shown in FIG. 2A, the first reactor includes a waste supply machine such as a piston / cylinder type extruder or a hopper for introducing the mixed waste W0 into the first reactor. The first reactor is connected to a water vapor supply line of a water vapor supply system facility, and is connected to an inorganic salt generating agent supply device for introducing an inorganic salt generating agent such as quick lime (CaO) into the first reactor. The

  The first reactor includes a stirring device for forcibly stirring the mixed waste W1 charged into the hydrothermal reaction zone in the container. The stirrer has a rotating shaft that is horizontally supported by the reactor body, a stirring blade that is fixed to the rotating shaft and extends in the radial direction from the rotating shaft, and an electric motor M that rotationally drives the rotating shaft. The object W1 is agitated by the rotational movement of the rotating shaft and the stirring blade.

  The waste supply machine introduces the mixed waste W0 into the first reactor under the control of the control device C / U, and the inorganic salt generating agent supply device controls the inorganic salt generating agent such as quick lime (CaO). It is introduced into the first reactor under the control of C / U.

  Saturated steam at a predetermined pressure is supplied to the hydrothermal reaction zone in the first reactor under the control of the control device C / U via the steam supply line, and the saturated steam is hydrothermal reaction zone in the first reactor. To charge. The mixed waste and the inorganic salt generating agent in the first reactor are mixed and stirred by a stirrer, and the mixed waste comes into mixed contact with saturated steam. The saturated water vapor in the reaction zone condenses on the surface of the mixed waste W1 and releases a large amount of latent heat. As a result of the large latent heat held by the water vapor being absorbed by the mixed waste W1, the thermal decomposition reaction of the mixed waste W1 proceeds, and the mixed waste W1 is refined or pulverized.

  The pressure and temperature in the first reactor are those of saturated steam, and as described above, within the range of 2.0 to 3.0 MPa and about 212 to 233 ° C., preferably 2.5 to 3. The pressure and temperature within the range of 0 MPa and about 224 to 233 ° C., for example, 2.8 MPa and the pressure and temperature of about 230 ° C. are maintained for a predetermined time. As described above, in the pyrolysis reaction that proceeds under such temperature conditions, the organic chlorine content in the mixed waste tends to be transferred to water vapor as hydrogen chloride (HCl), but the organic chlorine content in the mixed waste is reduced. Reacts rapidly with the metal element (such as Ca) of the inorganic salt generating agent to generate an inorganic salt. That is, the added inorganic salt generator suppresses the vaporization of hydrogen chloride (HCl). The inorganic salt produced in the first reactor remains as a solid content in the waste.

  The control device C / U holds the pressure and temperature of the saturated steam in the first reactor for a predetermined time, and then discards the first reactor so that the steam in the first reactor is discharged as waste steam to the waste water treatment device. A steam discharge device (not shown) is controlled, and the waste steam is discharged to the waste water treatment device as shown in FIG. The waste steam is condensed and subjected to neutralization in the waste water treatment apparatus, and then drained out of the system through a drain system pipe line (not shown). As described above, since the inorganic salt generating agent suppresses the vaporization of hydrogen chloride (HCl), the amount of hydrogen chloride transferred to the water vapor is considerably reduced. As a result, the load on the waste water treatment apparatus is reduced. Therefore, the capacity and treatment performance of the waste water treatment device can be greatly reduced.

  If desired, a ventilation facility or a supply / exhaust facility for ventilating the atmosphere in the first reactor is disposed in the first reactor, and the first reactor is ventilated at a predetermined time after waste steam. It may be configured.

  As shown in FIG. 2 (B), the solid content W1 ′ remaining in the first reactor is transferred to the second reactor, where it is subjected to drying treatment (or dehydration / drying treatment) in a room temperature ventilation drying system. . The second reactor is connected to a ventilation air supply pipe and an exhaust pipe for drying the solid content W2 in the second reactor. A blower (not shown) is interposed in at least one of the air supply pipe and the exhaust pipe, and normal temperature outside air is forcibly ventilated to the second reactor.

  As shown in FIG. 2C, the solid content W2 after drying is discharged from the second reactor as a regenerated solid fuel that has been refined or pulverized and subjected to inorganic chlorination of organic chlorine. On the other hand, the mixed waste W1 is newly supplied into the first reactor by the waste supplier, and high-temperature and high-pressure saturated steam is introduced into the first reactor by the steam supply system equipment. As described above, the mixed waste W1 is stirred by the rotational movement of the rotating shaft and the stirring blade, and the hydrothermal treatment (inorganic chlorination of organic chlorine) of the mixed waste W1 proceeds in the first reactor. Thereafter, the steps shown in FIGS. 2A to 2C are repeatedly performed.

  The present inventors conducted a hydrothermal treatment experiment using the waste treatment apparatus shown in FIGS. Tables 1 to 3 described below show the results of the hydrothermal treatment experiment.

  Table 1 shows the components of the inorganic salt-forming agent (additive) used in the hydrothermal treatment experiment. As shown in Table 1, an additive mainly composed of quick lime (CaO) was used as an inorganic salt generator. Samples 1 to 5 shown in Table 2 were prepared as specimens for the hydrothermal treatment experiment.

  Samples 1 to 5 were each charged into the first reactor and subjected to the hydrothermal treatment described above in the presence of saturated water vapor having a pressure of 2.4 MPa and a temperature of about 220 ° C. supplied into the first reactor. The hydrothermal treatment time was set at 90 minutes. Samples 4 and 5 are taken out of the waste treatment apparatus after a hydrothermal treatment and heated for about 1 hour, and samples 2 and 3 are taken out of the waste treatment apparatus immediately after the hydrothermal treatment and without a drying process. It was.

  Sample 1 is a sample that simulates PVC (polyvinyl chloride) contained in mixed waste, and is a raw material for testing that is obtained by appropriately cutting a PVC pipe that is commercially available as a plumbing pipe for water supply and drainage facilities such as buildings. is there.

  Sample 2 contains an additive containing quick lime in an amount equivalent to 3 times the amount (ie, 6 equivalents) of the quick lime that reacts with 1 equivalent of chlorine contained in PVC (2 equivalents). The sample is added and mixed.

  In Sample 3, an additive containing quick lime in an amount corresponding to twice the theoretical amount (2 equivalents) of quick lime reacting with 1 equivalent of chlorine contained in PVC (2 equivalents) is added to Sample 1. The sample is added and mixed.

  Sample 5 is unadjusted medical waste discharged from an actual medical facility (hospital), and Sample 4 contains an appropriate amount of inorganic salt generating agent (additive) for the medical waste of Sample 5. This is a mixed sample.

  Table 2 shows the total chlorine (organic chlorine and inorganic chlorine) content (% by weight) of Samples 1 to 5 measured by the Eshka method. FIG. 3 is a diagram showing the total chlorine content shown in Table 2.

  In the samples 2 and 3 to which quicklime was added, the ratio of relative chlorine content, that is, the total chlorine content, decreased as the total amount increased. Samples 4 and 5 are actual medical wastes, and the slight difference in the total chlorine content in samples 4 and 5 is not a significant numerical difference.

  Table 2 and FIG. 3 show the inorganic chlorine content (% by weight) and the organic chlorine content (% by weight) for each of Samples 2 to 5 taken from the first reactor. The inorganic chlorine content is the result of measuring the chlorine content of soluble chlorine (inorganic chlorine) eluted in the aqueous solution by washing samples 2 to 5, and the organic chlorine content is the insoluble chlorine (organic chlorine) remaining in the washing residue. It is a chlorine content measurement result. Further, Table 2 shows “a ratio of total chlorine as 100” regarding the organic chlorine content and the inorganic chlorine content. In addition, about the sample 1, although the value of an organic chlorine content rate and an inorganic chlorine content rate is not shown in Table 2, it is thought that all the chlorine contained in the sample 1 is organic chlorine. Further, as shown in the rightmost column of Table 2, the total value of the ratio of organic chlorine and inorganic chlorine does not match 100. This is due to a measurement error caused by the non-uniform mixing state of the sample after the hydrothermal treatment.

  As shown in Table 2, samples 2 and 3 after hydrothermal treatment contain a relatively large amount of inorganic chlorine. This means that most of the organic chlorine contained in Samples 2 and 3 was converted to inorganic chlorine by hydrothermal treatment. Moreover, when comparing the samples 4 and 5 after the hydrothermal treatment, in the sample 4 subjected to the hydrothermal treatment by adding the additive (quick lime), the inorganic chlorine content is higher than the organic chlorine content, whereas the additive (quick lime). On the other hand, in the sample 5 subjected to the hydrothermal treatment without adding, the inorganic chlorine content is lower than the organic chlorine content. This remarkably shows that organic chlorine can be converted to inorganic chlorine by performing a hydrothermal treatment in a state where an additive (quick lime) is added.

  Table 3 shows the weight ratio of moisture, combustible component, and ash component contained in each sample, and the total calorific value of each sample after drying, for samples 1 to 5 after hydrothermal treatment. In FIG. 4, the total calorific values in the dry state and the undried state are shown for samples 1 to 5 after the hydrothermal treatment.

  Both the medical wastes of Samples 4 and 5 have a high calorific value after hydrothermal treatment. When comparing sample 4 with sample 5, sample 4 has a relatively low combustible content due to the addition of an additive (quick lime), etc., so the total calorific value is also relatively low. . However, as shown in Table 2, a lot of organic chlorine is converted to inorganic chlorine in sample 4, and effective desalting treatment (inorganic chlorination treatment of organic chlorine) is performed on sample 4. Yes.

  When samples 1 to 3 are compared, in sample 2 to which a relatively large amount of additive (quick lime) is added, the combustible content is relatively lowered, and the calorific value is also reduced. This means that the addition of a large amount of additive (quick lime) causes a decrease in the calorific value of the regenerated fuel. In other words, excessive addition of additives (quick lime) reduces the calorific value of regenerated fuel, so there is a limit to the amount of additive (quick lime) added. There is a range of the amount of additive (quick lime) to be added according to the kind, component, etc. of the object, and further the calorific value of the target regenerated fuel.

  FIG. 5 is a block diagram schematically showing the overall configuration of a waste treatment apparatus for carrying out the mixed waste treatment method according to the second embodiment of the present invention, and FIG. 6 is a waste shown in FIG. It is a block flow figure showing roughly the structure and operation form of a processing unit.

  The waste disposal apparatus of the present embodiment has a single anti-container equipped with a forced drying facility of a hot air ventilation drying method. The forced drying facility includes a blower and an air supply pipe for introducing outside air into the reactor, and an exhaust pipe for exhausting the atmosphere in the reactor to the outside of the system. A heat exchanger is interposed in the air supply pipe. A heat medium circulation circuit that circulates the heat medium in the heat exchanger is connected to the heat exchanger. As a heat source constituting the heat medium circulation circuit, a steam supply source connected to the reactor may be used, or a heating device that heats the heat medium fluid with the same or equivalent fuel as the fuel of the steam supply source may be used. it can. A part of the regenerated solid fuel may be used as the fuel for such a heating device.

  As shown in FIG. 6 (A) and FIG. 6 (B), the mixed waste and the inorganic salt generating agent are introduced into the reactor, and the state in which the saturated steam at a predetermined pressure is filled in the reactor is maintained for a predetermined time. After that, the supply of water vapor is stopped, and the water vapor in the reactor is discharged as waste steam to the waste water treatment apparatus. Hydrogen chloride contained in the waste steam is removed in the waste water treatment apparatus. As shown in FIG. 6C, the air in the outside atmosphere heated by the heat exchanger is forcibly ventilated into the reactor under the blowing pressure of the blower, and the atmosphere in the reactor is forcibly ventilated. The product in the reactor (waste after hydrothermal reaction) is subjected to drying treatment with warm air, and then as a regenerated solid fuel containing inorganic salt (generated by reaction of hydrogen chloride and inorganic salt generator) Discharged from the reactor.

  Since the other operation steps of the waste treatment apparatus shown in FIG. 6 are substantially the same as the operation steps of the waste treatment apparatus shown in FIGS. 1 and 2, the description of the above-described embodiment is cited. Therefore, duplicate descriptions are omitted.

  FIG. 7 is a block diagram of the waste treatment apparatus schematically showing the overall configuration of the waste treatment apparatus for carrying out the mixed waste treatment method according to the third embodiment of the present invention.

  The waste treatment apparatus of this example is a room temperature (equivalent to atmospheric temperature) water (liquid phase) or heated as a means for eluting and removing inorganic salts contained in the solid content remaining in the first reactor. Water (liquid phase) is added to the solid content of the first reactor (waste after hydrothermal treatment) and a mixing and stirring tank for mixing and stirring the solid content and water is provided, and the mixed slurry generated in the mixing and stirring tank is dehydrated. A solid-liquid separator. The mixing and stirring device is provided with a mixing and stirring mechanism that disperses the solid content well in water, and the inorganic salt in the solid content dissolves in water and diffuses in water. Preferably, the weight of water to be supplied into the mixing and stirring tank is set in the range of 2 to 50 parts by weight with respect to 1 part by weight of the solid content.

  The mixed slurry obtained by the mixing and stirring process in the mixing and stirring tank is introduced into the solid-liquid separator through a pipe line such as a slurry feed pipe. As the solid-liquid separator, a mechanical dehydrator of a pressure dehydration method, a pressure dehydration method, or a centrifugal dehydration method can be preferably used. The desorbed liquid separated in the solid-liquid separation device is discharged to a wastewater treatment device through a waste liquid pipe or the like. The solid content obtained by the solid-liquid separation is supplied to the second reactor, subjected to a drying treatment as described above, and then discharged from the second reactor as a regenerated solid fuel.

  8 and 9 are block flow diagrams schematically showing the structure and operation mode of the waste disposal apparatus shown in FIG.

  As shown in FIG. 8A, the mixed waste W1 and the inorganic salt-generating agent in the first reactor are stirred in the presence of saturated steam, and the mixed waste W1 is subjected to a pyrolysis treatment. As shown in FIG. 8B, the solid content W1 ′ remaining in the first reactor is introduced into the mixing and stirring tank, and at the same time, a predetermined amount of water is supplied into the mixing and stirring tank. The solid content is mixed with water in the tank and slurried by mixing and stirring. The mixing and stirring mechanism of the mixing and stirring tank rotates and rotates the stirring blade in the tank, and the inorganic salt contained in the solid content is dissolved in water and diffused in water.

  The mixed slurry produced in the mixing and stirring tank is introduced into a solid-liquid separator. This process is shown in FIG. The desorbed liquid separated from the solid content in the dehydrator is discharged to the waste water treatment device through the waste liquid pipe, and only the solid content W2 after the dehydration is supplied to the second reactor. As shown in FIG. 9B, the solid content W2 is discharged from the second reactor as a regenerated solid fuel after being dried. On the other hand, the mixed waste W1 and the inorganic salt generating agent are newly supplied into the first reactor, and high-temperature and high-pressure saturated steam is introduced into the first reactor by the steam supply system facility. Thereafter, the steps shown in FIGS. 8 and 9 are repeatedly performed. The other operation steps of the waste treatment apparatus shown in FIGS. 8 and 9 are substantially the same as the operation steps of the waste treatment apparatus shown in FIGS. Duplicate description is omitted by quoting.

  The preferred embodiments and examples of the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiments and examples, and is within the scope of the present invention described in the claims. Various modifications or changes are possible.

  For example, in the first and third examples, the second reactor has a configuration including a drying treatment means of a room temperature ventilation drying method, but depending on the local weather conditions, environment, etc., the warm air ventilation drying is performed. A method of drying treatment may be provided in the second reactor.

  As a means for drying the solid content, it is possible to adopt a natural drying type drying processing means depending on the local weather conditions, environment, and the like. In this case, the installation of the second reactor intended for the drying process and the installation of equipment for drying process such as a blower, a heat source, and a heat exchanger can be omitted.

  INDUSTRIAL APPLICABILITY The present invention is preferably applied to a waste desalination method and a waste desalination apparatus for removing organic chlorine in waste when regenerating mixed waste by heat treatment with steam. According to the desalination method or desalination apparatus of the present invention, wastes such as household garbage, waste plastics, biomass waste, medical waste, etc. discharged from a building or a group of buildings are desalted. It can be refined and pulverized. The regenerated solid fuel after the desalting treatment obtained by the desalting method or desalting apparatus of the present invention is, for example, fueled in a furnace or combustion equipment such as a boiler, a combustion furnace, a gasification furnace, a pyrolysis furnace, or a power generator. Alternatively, it is supplied as a gasification raw material, or is supplied as an oily raw material to a waste plastic oil converting apparatus. Thus, the desalination method or desalination apparatus of the present invention can be positioned or grasped as a pretreatment facility for pulverizing and desalinating the regenerated fuel to be supplied to the combustion furnace, combustion facility, oiling facility, etc. . According to the waste desalination method and the waste desalination apparatus of the present invention, a high-performance or large-sized heating device is reacted to heat the atmosphere in the container without greatly reducing the calorific value of the regenerated solid fuel. Since the mixed waste containing organic chlorine can be heated and effectively crushed and desalted without being provided in the container itself, its practical effect is remarkable.

Claims (9)

In a waste desalination method in which mixed waste containing organic chlorine is thermally decomposed and desalted in a high-temperature and high-pressure container area,
Introducing the waste and a metal element compound that reacts with organic chlorine in the waste to form an inorganic salt into the reactor;
In the state in which saturated steam having a predetermined pressure within a range of 2.0 to 3.0 MPa is supplied into the reactor and the temperature in the reactor is maintained at the temperature of the saturated steam, the waste and the compound Are mixed and stirred to thermally decompose the mixed waste, and react with the organic chlorine and the metal element to produce an inorganic salt,
Waste demineralization characterized in that the water vapor in the reactor is led out of the reactor, and the solid content remaining in the reactor and containing the inorganic salt is led out of the reactor as a regenerated solid fuel. Method.   The metal element is at least one metal element selected from the group consisting of calcium, magnesium, sodium, and potassium, and the compound is an oxide, hydroxide, or carbonate of the metal element. The waste desalination method according to claim 1.   The pressure of the saturated steam is set to a predetermined pressure within a range of 2.5 to 3.0 MPa, and the temperature in the reactor is maintained at the temperature of the saturated steam for a predetermined time. The method for desalinating waste described in 1.   The waste desalination method according to any one of claims 1 to 3, wherein the predetermined time is set to a time of 30 minutes or more.   Water is added to the solid content remaining in the reactor and the solid content is mixed and stirred for a predetermined time. Alternatively, the solid content in the reactor is introduced into a mixing and stirring tank for water addition and mixed and stirred for a predetermined time. 5. The waste desalting method according to claim 1, wherein the inorganic salt remaining in the solid content is eluted in water.   The waste desalination method according to any one of claims 1 to 5, wherein the solid content is transferred from the reactor to a second reactor and dried in the second reactor. In a waste desalination system that desalinates by decomposing mixed waste containing organic chlorine by thermal decomposition in a high-temperature and high-pressure container area,
A reactor into which the waste is introduced;
An inorganic salt generator supply device for introducing into the reactor a compound of a metal element that reacts with organic chlorine in the waste to generate an inorganic salt;
A steam supply device for supplying saturated steam having a predetermined pressure within a range of 2.0 to 3.0 MPa into the reactor;
A stirring device for mixing and stirring the waste and the compound,
The waste water and the compound are mixed by operating the stirring device in a state where the saturated water vapor is filled in the reactor by the water vapor supply device and the temperature in the reactor is maintained at the temperature of the saturated water vapor. A waste desalination apparatus characterized by stirring.   The waste desalination apparatus according to claim 7, further comprising a second reactor for drying the solid content.   It further comprises a mixing and stirring tank for adding water to the solid content remaining in the reactor, mixing and stirring the solid content for a predetermined time, and eluting the inorganic salt remaining in the solid content into water. The waste desalination apparatus according to 7 or 8.

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