JP2010195994A - Method and apparatus for producing dechlorinated fuel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for producing a dechlorinated fuel, which suppresses reduction in carbon content ratio while removing chlorine in a waste. <P>SOLUTION: Volatile chlorine-containing organic waste is used as a raw material 11 and the raw material is exposed to steam 13 and hydrothermally decomposed in a reaction vessel 12 under pressure of ≥2.0 MPa and ≤3.0 MPa at ≥200°C and ≤250°C. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method and apparatus for producing dechlorinated fuel, and relates to a technique for reducing the chlorine concentration in a raw material when producing fuel from waste such as combustible waste containing organic chlorine. .

  Conventionally, as this type of technology, for example, there is one described in Patent Document 1. In Patent Document 1, a solid waste containing a large amount of vinyl chloride or other chlorine-containing resin is made into a waste slurry by a pretreatment means. Moreover, after heating and pressurizing organic sludge, it depressurizes instantaneously and the sludge is expanded to produce an expanded sludge slurry. Then, the waste slurry and the expanded sludge slurry are supplied to the mixing tank to obtain a mixed waste slurry. Next, the mixed waste slurry is hydrothermally reacted in a reactor to obtain a reaction slurry, followed by flushing and dewatering to obtain a cake-like dechlorinated raw fuel and filtrate.

Japanese Patent Laid-Open No. 11-267698

  In the above-mentioned Patent Document 1, the operating temperature of the reactor is raised to an appropriate temperature of about 250 to 350 ° C., and the mixed waste slurry is sent to the reactor in a state pressurized to about 170 atm by a high-pressure pump. Thermal decomposition is carried out by hydrothermal reaction at a pressure equal to or higher than the saturated water vapor pressure of the reaction temperature and for a reaction time of several minutes to several tens of minutes.

  By the way, when chlorine is separated at a high reaction temperature of 350 ° C. or more, the liberated chlorine moves to the gas side and causes the reaction vessel to corrode. In addition, if the waste contains a dioxin precursor, the liberated chlorine may be combined with the precursor to synthesize dioxins. Furthermore, since carbon contained in the waste is also gasified under a high reaction temperature of 300 ° C. or higher, the carbon content in the dechlorinated raw fuel is lowered, and the value as a fuel is reduced.

  This invention solves the above-mentioned subject, and it aims at providing the manufacturing method and manufacturing apparatus of a dechlorination fuel which can suppress the fall of a carbon content rate, removing the chlorine in a waste material.

  In order to solve the above problems, a method for producing a dechlorination fuel according to the present invention uses an organic waste containing organic chlorine as a raw material, a pressure of 2.5 MPa to 3.0 MPa, and a temperature of 230 ° C. or higher in a reaction vessel. The raw material is hydrothermally decomposed by being exposed to saturated steam at 250 ° C. or lower, and the product in the reaction vessel generated by hydrothermal decomposition is dehydrated to obtain a fuel raw material.

  Moreover, after raising the temperature in the reaction vessel to 230 ° C. or more and 250 ° C. or less with saturated steam, the pressure in the reaction vessel is raised to 2.5 MPa or more and 3.0 MPa or less, and then the pressure is 2.5 MPa or more and 3.0 MPa or less and the temperature is 300 ° C. The raw material is exposed to superheated steam at 350 ° C. or lower.

The product in the reaction vessel is dehydrated after washing with water.
Further, the fuel raw material is used as a fuel for a steam supply device that supplies saturated steam to the reaction vessel.

  The apparatus for producing dechlorinated fuel of the present invention comprises a reaction vessel holding organic waste containing organic chlorine as a raw material, a pressure of 2.5 MPa to 3.0 MPa, a temperature of 230 ° C. to 250 ° C. in the reaction vessel. It is characterized by comprising a steam supply device for supplying saturated steam and a washing and dehydrating device for washing and dewatering the product in the reaction vessel.

  Moreover, in order to raise the reaction container holding the organic waste containing organic chlorine as a raw material, the reaction container temperature to 230 ° C. to 250 ° C., and the reaction container pressure to 2.5 MPa to 3.0 MPa. A steam supply device for supplying the saturated water vapor to the reaction vessel, and the pressure inside the reaction vessel rises to the temperature inside the reaction vessel and the pressure inside the reaction vessel, and then the pressure pressure is 2.5 MPa to 3.0 MPa, the temperature is 300 ° C. to 350 ° C. A superheated steam supply device that supplies the following superheated steam to the reaction vessel and a washing and dehydration device that dehydrates the product in the reaction vessel by washing with water are provided.

  As described above, according to the present invention, at least a part of organic chlorine in the raw material is liberated by exposing the raw material to saturated water vapor at a pressure of 2.5 MPa to 3.0 MPa and a temperature of 230 ° C. to 250 ° C. It becomes inorganic chlorine and immediately combines with the water in the reaction vessel and moves to the liquid phase side. For this reason, it can be easily dechlorinated by washing and dehydrating.

  In addition, since the gasification of carbon in the raw material can be suppressed at a water vapor temperature of 250 ° C. or lower, the carbon contained in the waste raw material remains in the dechlorinated fuel raw material, and the carbon content in the fuel raw material is The value as fuel increases. Furthermore, since the chlorine concentration in the manufactured fuel raw material has been reduced, it is difficult for hydrogen chloride gas to be generated during combustion of the fuel, corrosion of the furnace wall of the combustion apparatus can be suppressed, and generation of dioxins during combustion is suppressed. be able to.

The block diagram which shows the manufacturing apparatus in embodiment of this invention The block diagram which shows the manufacturing apparatus in other embodiment of this invention The block diagram which shows the manufacturing apparatus in other embodiment of this invention Schematic diagram showing the equipment used in the experiment

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Embodiment 1
In FIG. 1, a raw material 11 is a solid organic waste containing organic chlorine, such as combustible waste, kitchen waste, plastic waste, and the like. A reaction vessel 12 performs a hydrothermal decomposition reaction with saturated steam 13. is there.

  The saturated water vapor 13 supplied to the reaction vessel 12 is saturated water vapor having a pressure of 2.5 MPa to 3.0 MPa and a temperature of 230 ° C. to 250 ° C. The reason for using saturated steam having a pressure of 2.5 MPa or more is that consideration is given to the refinement of the raw material 11 by the hydrothermal decomposition reaction described later. That is, since the plastics contained in the raw material 11 cannot be finely granulated with 2 MPa saturated steam, saturated steam with a pressure of 2.5 MPa or more, which is a set pressure necessary to finely plasticize the plastics, is used. The exhaust gas 14 is for exhausting the reaction vessel 12 under reduced pressure after the hydrothermal decomposition reaction.

  The cleaning / dehydrating means 15 is composed of a water cleaning device and a dehydrating device, and cleans and dehydrates the solid-liquid suspension 16 discharged from the reaction vessel 12. The water washing apparatus comprises a mixing tank capable of adding 3 to 10 times the amount of water to the solid-liquid suspension and stirring uniformly. The stirring method is mechanical stirring or air stirring.

  As the dehydrator, a centrifugal dehydrator, a belt press dehydrator, a filter press dehydrator, a screw press dehydrator, or the like can be used. A dehydration aid such as an inorganic flocculant or an organic flocculant is added as needed during dehydration. The drying device 21 dries the solid material 17 taken out from the washing / dehydrating means 15 to obtain the fuel raw material 18, and an air dryer, an indirect dryer, a sun dryer or the like can be used. The separation liquid 19 discharged from the cleaning / dehydrating means 15 is subjected to drainage treatment 20. As the wastewater treatment, biological treatment methods such as activated sludge method and contact aeration method and physicochemical treatment methods such as coagulation sedimentation, filtration and activated carbon treatment can be used.

In the above configuration, the dechlorination fuel is manufactured by the following steps.
Reaction Step After charging the raw material 11 into the reaction vessel 12, saturated water vapor having a pressure of 2.5 MPa to 3.0 MPa and a temperature of 230 ° C. to 250 ° C. is blown into the reaction vessel 12 as saturated water vapor 13. The pressure is increased to 2.5 MPa or higher and the temperature is increased to 230 ° C. or higher. Inside the reaction vessel 12, the raw material 11 is exposed to saturated steam at a pressure of 2.5 MPa to 3.0 MPa and a temperature of 230 ° C. to 250 ° C., and the organic waste of the raw material 11 is finely divided by the hydrothermal decomposition reaction. It becomes a solid-liquid suspension state (slurry), and at least a part of the organic chlorine contained in the raw material 11 is liberated to become inorganic chlorine. At this time, the liberated inorganic chlorine does not move to the gas side, but immediately combines with the water inside the reaction vessel 12 and moves to the liquid phase side, and hardly exists in the gaseous state.
Depressurization Step After the internal pressure of the reaction vessel 12 reaches a predetermined pressure, the inside of the reaction vessel 12 is depressurized to atmospheric pressure and adiabatically expanded. This is done by discharging the product gas inside the reaction vessel 12 as exhaust gas 14. At this time, a part of the water contained in the raw material 11 is evaporated and transferred to the exhaust gas 14, and the input steam (saturated steam) supplied to the reaction vessel 12 is gasified from the raw material 11 together with some carbon. Transition. In addition, inorganic chlorine released from the raw material 11 is combined with moisture inside the reaction vessel 12 and moves to the liquid phase side and hardly exists in gaseous form. Therefore, when the inside of the reaction vessel 12 is decompressed, the inorganic chlorine Hardly moves to the exhaust gas side, and corrosion of the reaction vessel 12 can be prevented.
Washing / Dehydration Process The solid / liquid suspension 16 of the product is taken out from the reaction vessel 12 to the washing / dehydrating means 15. The solid-liquid suspension 16 contains most of carbon of the organic substance of the raw material 11 on the solid phase side, and contains inorganic chlorine on the liquid phase side. The solid-liquid suspension 16 is diluted and washed with water, and then dehydrated to separate into a solid 17 and a separation liquid 19. At this time, since the inorganic chlorine contained in the liquid phase moves to the separation liquid 19, the solid material 17 after dehydration has an excellent fuel raw material 18 having a low chlorine concentration, a high carbon content, and a high fuel value. It becomes.

That is, in the hydrothermal decomposition reaction with saturated steam at a pressure of 2.5 MPa or more and 3.0 MPa or less and a temperature of 230 ° C. or more and 250 ° C. or less, the gasification of carbon is small and most volatile carbon remains in the fuel raw material 18. The fuel material 18 can be obtained in which the calorific value is maintained higher than the conventional method of gasifying and burning most of the volatile carbon such as carbonization.
Drying Process The produced fuel material 18 is dried by a drying device 21. Since the fuel raw material 18 has a reduced chlorine concentration, it is difficult for hydrogen chloride gas to be generated during combustion of the fuel, corrosion of the furnace wall of the combustion apparatus can be suppressed, and generation of dioxins can be suppressed during combustion. .
Wastewater treatment step Since the separation liquid 19 contains water-soluble organic substances generated by hydrothermal decomposition reaction in addition to inorganic chlorine, for example, it is treated by an activated sludge method including a biological nitrification denitrification treatment method. The concentration of chlorine contained in the separation liquid 19 is usually 1% or less, which is a category that can be treated without any problem by the conventional activated sludge treatment method. In this waste water treatment step, the activated sludge can be treated together with the condensate of the exhaust steam contained in the exhaust gas 14.

  As another embodiment of the present invention, as shown in FIG. 2, the internal temperature of the reaction vessel 12 is set to a predetermined temperature with saturated steam at a pressure of 2.5 MPa to 3.0 MPa and a temperature of 230 ° C. to 250 ° C. After increasing the internal pressure to a predetermined pressure, superheated steam 22 having a pressure of 2.5 MPa to 3.0 MPa and a temperature of 300 ° C. to 350 ° C. is supplied to the reaction vessel 12 so that the internal temperature is 300 ° C. or higher. It is also possible to expose the raw material 11 to the superheated steam 22.

  In this case, although the gasification rate of carbon is slightly higher than that of the previous embodiment and the total calorific value is reduced, the concentration of chlorine contained in the fuel material 18 is further reduced by increasing the gasification rate of organic chlorine. Can do.

  As other embodiment of this invention, as shown in FIG. 3, it is also possible to use the fuel raw material 18 as a fuel of the boiler 23 which comprises the steam supply apparatus which supplies saturated water vapor | steam to the reaction container 12. As shown in FIG.

In this case, since the chlorine concentration of the fuel raw material 18 is reduced, generation of hydrogen chloride gas can be suppressed during fuel combustion, corrosion of the furnace wall of the boiler 23 can be suppressed, and generation of dioxins can be suppressed during combustion. And fuel costs can be reduced.
Experimental Example An experimental example according to the present invention will be described.
1. Adjustment of input raw materials Three types of materials were blended to set standard raw materials.
Organic matter: Dock food (crude protein: crude fat: crude fiber: crude ash content = 26: 12: 4: 9.5)
-Inorganic chlorine: Sodium chloride-Organic chlorine: Vinyl chloride polymer-Moisture The raw material water content was adjusted to 60%, and then water equivalent to saturated steam (at 230 ° C) was added.
-Chlorine concentration Adjusted to 1% inorganic chlorine and 1% organic chlorine.
2. Analytical Method / Weight Measurement Measured with Electronic Balance / Solid Concentration JIS Method / Chlorine Water Extraction Rate Add 5 g of sample into a 200 ml flask, add 100 ml of hot water at 80 ° C., shake at 80 ° C. and 60 rpm in a shaking water bath for 1 hour. I will. The total amount was filtered with a filter paper, and the total chlorine ion amount (a) in the filtrate was measured by ion chromatography (ICS-1500, manufactured by Nippon Dionyx). The residue on the filter paper was dried overnight at 100 ° C., vaporized with a TOX meter (TOX-100 manufactured by Mitsubishi Chemical Corporation), and the total chlorine ions (b) in the residue were measured by ion chromatography as above.
Chlorine water extraction rate was calculated by the following formula. Chlorine water extraction rate (%) = [a / (a + b)] × 100
-Carbon gasification rate The total carbon amount (c) in a raw material, the total carbon amount (d) in exhaust gas, and the total carbon amount (e) in condensed water were measured with the TC meter.
The carbon gasification rate was determined by the following formula. Carbon gasification rate (%) = [(d + e) / c] × 100
3. Method for Producing Hydrothermal Reaction Product As shown in FIG. 4, the experimental machine comprises a reaction vessel 72, a stirrer 73, a heater 69, an exhaust valve 70, and an air supply valve 71. Four batches of tests 1 to 4 described later were performed according to the following procedure.
1) Organic matter, inorganic chlorine, organic chlorine, and water were put into the reaction vessel 72, the exhaust valve 70 and the air supply valve 71 were closed, and the stirring by the stirrer 73 and the temperature increase by the heater 69 were started.
2) While the internal temperature of the reaction vessel 72 was 80 to 110 ° C., the exhaust valve 70 was slightly opened to vent the air inside.
3) For tests 1 to 3, the same condition was maintained for 5 minutes after the internal temperature of the reaction vessel 72 reached 230 ° C. For Test 4, the same conditions were maintained for 5 minutes after the internal temperature of the reaction vessel 72 reached 295 ° C.
4) After stopping the heater 69, the exhaust valve 70 was gradually opened to release exhaust steam / exhaust gas.
5) After exhausting, the air supply valve 71 was opened and air was blown by the air supply device 62, followed by drying for 10 minutes.
6) After drying, the exhaust valve 70 was closed and the reaction vessel 72 was left until the internal temperature became 80 ° C. or lower.
7) After the internal temperature decreased, the agitator 73 was stopped, the lid was opened, and the hydrothermal reaction product 68 was sampled.
4). Hydrothermal reaction temperature and properties of the hydrothermal reaction product In tests 1 to 3 performed at a reaction temperature of 230 ° C. and a reaction pressure of 2.5 to 2.6 MPa, the chlorine water extraction rate of the raw material, which averaged 58.8%, averaged 81 Increased to 9%. This indicates that the vinyl chloride polymer added to the raw material was converted into inorganic chloride ions and easily extracted into water. The carbon gasification rate at this time was 10.4% on average. On the other hand, in test 4 performed at a reaction temperature of 300 ° C. and a reaction pressure of 2.9 MPa, the chlorine water extraction rate of the raw material, which was 58.6%, increased to 98%, and more inorganic chlorine ions than in tests 1 to 3 Has been converted. Moreover, the carbon gasification rate increases to 18.7%, and it can be seen that in the hydrothermal reaction at a high temperature of 300 ° C., the yield of fuel components decreases although chlorine can be removed more.

Charge 800 kg of household combustible waste as a collection bag into a 3 m ³ reaction vessel, introduce 3 MPa saturated water vapor into the vessel, raise the temperature to 2.8 MPa and raise the temperature to 230 ° C, and in that state The hydrothermal decomposition was performed for about 10 minutes. During hydrothermal decomposition, the stirring blade in the apparatus was stirred in the forward direction, and then the product was discharged by rotating the stirring blade in the reverse direction after decompression. As a result, 450 kg (water content 11.7%) of the product after the reaction was recovered.

100 kg of the product was placed in a 1000 L tank, 900 L of tap water was added, and the mixture was mixed with a stirrer to obtain a 3.3% solid-liquid suspension. After adding 200 L of 0.2% cationic polymer solution to this solid-liquid suspension and agglomerating with slow stirring for 15 minutes, the solid-liquid suspension was precipitated to obtain a concentrated solid-liquid suspension concentrated about 9 times. It was. This concentrated solid-liquid suspension was supplied to a belt press type dehydrator for dehydration to obtain a dehydrated cake having a water content of 26.6%. The dehydrated cake was dried with a flash dryer (inlet temperature 90 ° C., outlet temperature 40 ° C.) to obtain a dry fuel having a water content of 10%.
The total chlorine concentration of hydrothermal decomposition products and washing dehydration was as follows.

DESCRIPTION OF SYMBOLS 11 Raw material 12 Reaction container 13 Saturated steam 14 Exhaust gas 15 Cleaning | dehydration means 16 Solid-liquid suspension 17 Solid material 18 Fuel raw material 19 Separation liquid 20 Wastewater treatment 21 Drying apparatus 22 Superheated steam 23 Boiler

Claims (6)

  Using organic waste containing organic chlorine as a raw material, hydrothermal decomposition of the raw material by hydrothermal decomposition of the raw material by exposing it to saturated water vapor at a pressure of 2.5 MPa to 3.0 MPa and a temperature of 230 ° C. to 250 ° C. A method for producing a dechlorinated fuel, comprising dehydrating a product in a reaction vessel produced by the step 1 into a fuel raw material.   After increasing the temperature in the reaction vessel to 230 ° C. or more and 250 ° C. or less with saturated steam, the pressure in the reaction vessel is raised to 2.5 MPa or more and 3.0 MPa or less, and then the pressure is 2.5 MPa or more and 3.0 MPa or less, and the temperature is 300 ° C. or more and 350 ° C. The method for producing a dechlorinated fuel according to claim 1, wherein the raw material is exposed to superheated steam at a temperature not higher than ° C.   The method for producing a dechlorinated fuel according to claim 1 or 2, wherein the product in the reaction vessel is dehydrated after washing with water.   The method for producing a dechlorinated fuel according to any one of claims 1 to 3, wherein the fuel raw material is a fuel of a steam supply device that supplies saturated steam to the reaction vessel.   A reaction vessel that holds organic waste containing organic chlorine as a raw material, a steam supply device that supplies saturated water vapor with a pressure of 2.5 MPa to 3.0 MPa, a temperature of 230 ° C. to 250 ° C., and a reaction An apparatus for producing dechlorinated fuel, comprising a washing and dehydrating device for dehydrating a product in a container by washing with water.   A reaction vessel holding organic waste containing organic chlorine as a raw material, and saturation for raising the reaction vessel temperature to 230 ° C. to 250 ° C. and the reaction vessel pressure to 2.5 MPa to 3.0 MPa A steam supply device for supplying water vapor to the reaction vessel; and after the inside of the reaction vessel has risen to the reaction vessel temperature and the reaction vessel pressure, the pressure pressure is 2.5 MPa to 3.0 MPa, and the temperature is 300 ° C. to 350 ° C. An apparatus for producing dechlorinated fuel, comprising: a superheated steam supply device that supplies superheated steam to a reaction vessel; and a washing and dehydrating device that dehydrates the product in the reaction vessel by washing with water.

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