JP2011241339A - Desalter and desalting method for chlorine-containing waste material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To desalt a chlorine-containing waste material to be made a resource while holding down equipment cost and treatment cost.SOLUTION: A desalter 4 includes: a waste heat boiler 15 which heats a steam S by an exhaust gas G4 of a preheater 7 of a cement firing device 2, and forms a superheated steam SS; a rotary kiln-type heating furnace 17 which heats a chlorine-containing waste material W by the superheated steam SS formed with the waste heat boiler 15, and desalts the chlorine-containing waste material W; and a first gas treatment part 18 which makes an exhaust gas G5 discharged from the heating furnace 17 contact with a coarse powder D1 of a dust collected with a cyclone 11 of a chlorine bypass device 3, and makes a chlorine content in the exhaust gas G5 react with a calcium content in the coarse powder D1.

Description

  The present invention relates to a desalination apparatus and desalination method for chlorine-containing waste, and more particularly to a desalination apparatus for desalinating plastic waste to recycle it.

  In recent years, recycling of various wastes as raw materials or fuels has been promoted, and plastic waste (hereinafter referred to as “waste plastics”) is also required to be recycled. However, since waste plastic contains a lot of chlorine, for example, when it is used as fuel, problems such as corrosion of a combustion furnace and coating troubles due to generation of chloride occur.

  Therefore, for example, in Patent Document 1, as a method for efficiently recovering valuable materials such as oil while desalting the waste plastic, the volume of the waste plastic is reduced by heating with superheated steam at 300 to 500 ° C. After that, a processing method has been proposed in which the volume-reduced object to be processed is further thermally decomposed by heating with superheated steam at 500 to 600 ° C., and gas generated by the thermal decomposition is liquefied to recover oil.

  Patent Document 2 is not based on the premise of recycling of waste plastic, but as a method for providing an alternative to landfill treatment, carbon dioxide residue after dry distillation is obtained by carbonizing waste plastic using superheated steam. Has been disclosed that includes a dry distillation and incinerator for incinerating water and a recovery device for absorbing and recovering hydrogen chloride gas generated by dry distillation in water.

  Furthermore, in Patent Document 3, as a method for heat-treating organic waste without generating tar, a rotary kiln-type gasification furnace charged with waste organic waste containing waste plastic is placed at 600 to 1000 ° C. A processing method is disclosed in which high temperature water vapor is blown to gasify organic waste.

JP 2004-359897 A JP-A-10-216674 JP 2000-296378 A

  However, when waste plastic is desalted by heat treatment as in the treatment methods described in Patent Documents 1 to 3, hydrogen chloride (HCl) gas is generated, so that the generated gas is brought into contact with an alkaline substance for neutralization. There is a need to. In general, NaOH is used as an alkaline substance for neutralization treatment. However, if the required amount is purchased and used, the cost of chemicals may exceed the value of waste plastic as fuel, depending on the chlorine concentration of waste plastic. It doesn't hold true.

  In addition, heat treatment of waste plastic with superheated steam is considered promising as a method capable of removing only chlorine while leaving a combustible component in waste plastic, but in the treatment methods described in Patent Documents 1 to 3 Since the steam is heated by the flame to generate the superheated steam, a dedicated combustion facility and fuel for generating the superheated steam are required, resulting in an increase in equipment cost and processing cost. Moreover, if fuel is used for the production of superheated steam, waste will be converted into fuel using the fuel, which is not meaningful.

  Then, this invention is made | formed in view of the problem in the said prior art, Comprising: It aims at desalinating chlorine containing waste and making it a resource, keeping processing cost low.

  In order to achieve the above object, the present invention provides a desalination apparatus for chlorine-containing waste, which uses waste heat discharged from a combustion furnace to heat the chlorine-containing waste and remove the chlorine-containing waste. It comprises heating means for salting, and chlorination means for bringing hydrogen chloride gas discharged from the heating means into contact with a substance containing CaO generated in the combustion furnace.

  And according to this invention, the chlorine content in hydrogen chloride gas can be made to adsorb | suck to the substance containing CaO, and can be removed. At this time, since a substance generated in the combustion furnace is used as the substance containing CaO, it is not necessary to purchase a chemical for treating hydrogen chloride gas, and the processing cost can be greatly reduced.

  Here, the chlorine-containing waste refers to waste plastics as a representative example, and includes at least one organic chlorine such as polyvinyl chloride or polyvinylidene chloride in a monomer as a constituent unit.

Moreover, the substance containing CaO is not particularly limited as long as it contains CaO as a component. For example, quick lime, slaked lime, calcium carbonate, dolomite (CaMg (CO ₃ ) ₂ ) and the like can be used. . However, calcium carbonate and dolomite are less reactive with hydrogen chloride gas than quick lime, and in the case of slaked lime, there is an extra step to convert CaO generated in the manufacturing process equipped with a combustion furnace into (CaOH) ₂ Necessary. In view of reactivity and ease of diversion to an absorbent, quicklime is preferred.

  In the above desalination apparatus for chlorine-containing waste, the apparatus comprises a superheated steam generating means for heating the steam with the waste heat of the combustion furnace and generating superheated steam, and the heating means is the superheated steam generated by the superheated steam generating means Can heat chlorine-containing waste.

  According to the above configuration, desalting can be performed while avoiding combustion of the chlorine-containing waste, and the reaction between the chlorine content in the hydrogen chloride gas and the substance containing CaO can be promoted. Furthermore, in the above configuration, since the superheated steam is generated by using the waste heat of the combustion furnace, a dedicated combustion facility and fuel for generating the superheated steam are not required, and the facility cost and the processing cost are kept low. Chlorine-containing waste can be desalted for recycling.

  In the above desalination apparatus for chlorine-containing waste, the combustion furnace is a cement kiln, and the material containing the CaO is recovered from dust collected by a chlorine bypass apparatus attached to the cement kiln or a bottom material extracted from a preheater It can be. According to this, chlorine-containing waste can be desalted by effectively using what is normally used or generated in a cement manufacturing factory, and the processing cost can be reduced.

  In the chlorine-containing waste desalination apparatus, the chlorine bypass device is configured to extract a part of the combustion gas from the cement kiln exhaust gas flow path from the bottom of the cement kiln to the bottom cyclone, and from the extracted gas. A classifier that separates coarse dust particles, and the substance containing CaO can be coarse powder separated by the classifier.

  In the chlorine-containing waste desalination apparatus, the combustion furnace is a quicklime furnace, and the substance containing the CaO can be quicklime generated in the quicklime furnace, and in particular, quicklime that cannot be commercialized is used. be able to. According to this, it is possible to desalinate chlorine-containing waste by effectively using unnecessary items generated at the quicklime production facility, and reduce the processing cost of chlorine-containing waste while efficiently processing unnecessary items. It becomes possible.

  In the chlorine-containing waste desalination apparatus, the heating means can be a rotary kiln type heating furnace, which enables stable continuous operation.

  In the chlorine-containing waste desalination apparatus, the superheated steam generation means can be a waste heat boiler.

  The present invention also relates to a method for desalinating chlorine-containing waste, which comprises heating the chlorine-containing waste using waste heat discharged from a combustion furnace and desalting the chlorine-containing waste. And a treatment step of bringing hydrogen chloride gas generated in the desalting step into contact with a substance containing CaO generated in the combustion furnace. According to the present invention, as in the case of the above-described invention, it is possible to desalinate the chlorine-containing waste and to recycle it while keeping the processing cost low.

  In the method for desalinating chlorine-containing waste, the method includes a step of heating steam with waste heat of the combustion furnace to generate superheated steam, and heating the chlorine-containing waste with the superheated steam in the desalting step. Can do.

  As described above, according to the present invention, the chlorine-containing waste can be desalted and recycled while keeping the processing cost low.

It is a flowchart which shows one Embodiment of the cement manufacturing factory to which the desalination apparatus of the chlorine containing waste concerning this invention is applied.

  Next, an embodiment for carrying out the present invention will be described in detail with reference to the drawings.

  The desalination apparatus for chlorine-containing waste according to the present invention is preferably used in combination with facilities such as cement production and quicklime production that generate substances containing CaO in the production process. In the following, a case where the desalination apparatus of the present invention is combined with a cement production facility will be described as an example.

  FIG. 1 shows an embodiment of a cement manufacturing plant to which a desalination apparatus for chlorine-containing waste according to the present invention is applied. The cement manufacturing plant 1 is roughly divided into a cement kiln 5, a calcining furnace 6, and Chlorine that removes chlorine by extracting a part of the combustion gas from the cement kiln 2 including the preheater 7 and the like and the cement kiln exhaust gas flow path from the kiln bottom 8 of the cement kiln 5 to the lowermost cyclone 7A of the preheater 7 A bypass device 3 and a desalting device 4 for desalting chlorine-containing waste W such as waste plastic are installed.

  The cement kiln 5, the calcining furnace 6 and the preheater 7 of the cement baking apparatus 2 are general facilities for manufacturing cement and are similar to those used in conventional cement baking apparatuses. The detailed description of is omitted. The cement baking apparatus 2 is provided with a generator 16 that generates power using the exhaust gas G4 of the preheater 7.

  The chlorine bypass device 3 includes a probe 10 for extracting a part of the combustion gas from the cement kiln exhaust gas flow path, and a cyclone 11 as a classifier for separating the dust coarse powder D1 from the extracted gas G1 extracted by the probe 10. And a bag filter 12 for collecting the dust fine powder D2 contained in the exhaust gas G2 of the cyclone 11 containing the fine powder D2.

  The demineralizer 4 heats the steam S using the exhaust gas G4 (400 to 450 ° C.) of the preheater 7 of the cement baking apparatus 2 and heats the waste heat boiler 15 that generates superheated steam SS and the chlorine-containing waste W. Heating furnace 17, first and second gas processing units 18 and 19 that render the gas (gas containing hydrogen chloride gas) G 5 generated in the heating furnace 17 harmless, and a chimney that releases the processed gas G 7 to the atmosphere 20 is composed.

  The heating furnace 17 is provided to thermally decompose the chlorine content in the chlorine-containing waste W using the superheated steam SS generated by the waste heat boiler 15. As the heating furnace 17, for example, various furnaces such as a stoker type, a fluidized bed type, and a rotary kiln type can be used. Among these, a rotary kiln type furnace having high suitability for an object to be heated having adhesiveness is used. preferable. In addition, since the thermal decomposition of chlorine is completed at 250 to 300 ° C., the temperature of the superheated steam SS used in the heating furnace 17 is sufficient to be about 300 to 400 ° C.

  The first gas processing unit 18 is provided to remove chlorine from the exhaust gas G5 of the heating furnace 17. In the first gas processing unit 18, a substance containing CaO is introduced, and the chlorine content in the exhaust gas G 5 is adsorbed and recovered by the substance. In the present embodiment, dust coarse powder D1 (a substance containing quicklime) separated by the cyclone 11 of the chlorine bypass device 3 is used as the substance containing CaO.

  Various types of reaction tanks such as a packed bed, a fluidized bed, and a moving bed can be used for the first gas processing unit 18. However, in order to adsorb the chlorine content in the exhaust gas G5, it is necessary to intentionally make the acid dew point or less by inserting a cooling gas.

  The second gas processing unit 19 is provided for removing chlorine remaining in the exhaust gas G6 of the first gas processing unit 18. An activated carbon adsorption tower, an alkali cleaning scrubber, or the like can be used for the second gas processing unit 19.

  Next, an operation method of the cement manufacturing factory 1 having the above configuration will be described with reference to FIG.

  In the cement baking apparatus 2, the raw material R supplied to the preheater 7 is preheated by the preheater 7, heated in the calcining furnace 6, and then fired in the cement kiln 5 to generate a cement clinker.

  In the chlorine bypass device 3, a part of the combustion gas is extracted by the probe 10 from the cement kiln exhaust gas flow path from the kiln bottom 8 of the cement kiln 5 to the lowermost cyclone 7 </ b> A, and at the same time, a cold air fan (not shown). Quench with cold air from Next, in the cyclone 11, the extracted gas G1 from the probe 10 is separated into coarse powder D1 and exhaust gas G2 containing fine powder D2. At this time, the chlorine content of the extraction gas G1 is unevenly distributed on the dust fine powder D2 side.

  Next, the exhaust gas G2 containing the fine powder D2 is cooled by a cooler (not shown), and then introduced into the bag filter 12 to collect the fine powder D2. The coarse powder D1 classified by the cyclone 11 is supplied to the first gas processing unit 18, and the fine powder D2 collected by the bag filter 12 is washed and desalted by a washing facility (not shown). Further, the exhaust gas G3 from the bag filter 12 is returned to the preheater 7 of the cement baking apparatus 2.

  In parallel with the above treatment, in the desalination apparatus 4, the waste heat boiler 15 exchanges heat between the exhaust gas G4 of the preheater 7 of the cement baking apparatus 2 and the steam S flowing through the heat transfer pipe 15a to generate superheated steam SS. . A part of the generated superheated steam SS is supplied to the generator 16 to be used for power generation, and the remainder of the superheated steam SS is supplied to the heating furnace 17 to be used for heating the chlorine-containing waste W. The exhaust gas G4 'after heat exchange is supplied to the cement raw material process 9 and used for drying the raw material R.

  In the heating furnace 17, the chlorine-containing waste W is heated by the superheated steam SS from the waste heat boiler 15, and the chlorine content is thermally decomposed and removed. The waste W ′ after desalting is used as a fuel for manufacturing cement.

  The heating method for desalinating the chlorine-containing waste W is not limited to the method using the superheated steam SS, and the exhaust gas G4 from the preheater 7 is directly blown into the heating furnace, or the exhaust gas is applied to the jacket provided in the heating furnace. Other heating methods such as indirect heating for heating the chlorine-containing waste W from the outside of the heating furnace through G4 can also be used.

  However, by using the heating method using the superheated steam SS, the chlorine-containing waste W can be desalted while avoiding the combustion of the chlorine-containing waste W, and this heating method is the first gas in the next stage. This is also preferable in relation to the processing unit 18.

Next, the exhaust gas G <b> 5 from the heating furnace 17 is guided to the first gas processing unit 18, and the coarse powder D <b> 1 recovered by the cyclone 11 of the chlorine bypass device 3 is introduced into the first gas processing unit 18. Thereby, the hydrogen chloride gas contained in the exhaust gas G5 is reacted with the calcium content in the coarse powder D1 to generate calcium chloride (CaCl ₂ ), and the chlorine content is adsorbed on the coarse powder D1.

  In order to react the chlorine content in the exhaust gas G5 with the calcium content in the coarse powder D1, it is necessary to adjust the temperature of the exhaust gas G5 below the acid dew point. In order to promote, it is preferable that a lot of moisture is contained in the exhaust gas G5. If the heating method using the superheated steam SS is used in the heating furnace 17, the moisture content of the exhaust gas G5 can be increased, and the chlorine adsorption reaction can be promoted.

  Coarse powder D1 adsorbed with chlorine can be treated if it is recovered and washed and desalted, but in this case, the cost of washing is required, so it is preferable to effectively use it without washing. For example, it is preferably used as a chlorination source in a method for recovering lead from a cement production process described in JP-A-2008-190019.

  After the processing in the first gas processing unit 18, the exhaust gas G6 of the first gas processing unit 18 is guided to the second gas processing unit 19 to remove a trace amount of remaining chlorine, and finally the chimney 20 is Through the atmosphere.

  As described above, according to the present embodiment, since the dust coarse powder D1 recovered by the chlorine bypass device 3 is used for removing chlorine from the exhaust gas G5 generated in the heating furnace 17, hydrogen chloride gas is used. It is not necessary to purchase a medicine for processing, and the processing cost can be greatly reduced.

  Moreover, since the superheated steam SS is generated using the exhaust gas generated in the cement firing device 2 (the exhaust gas G4 of the preheater 7), a dedicated combustion facility and fuel for generating the superheated steam SS are not required, and the equipment cost and Processing costs can be kept low. Furthermore, since no fuel is used for the production of the superheated steam SS, it is in line with the purpose of converting waste into fuel.

  In addition, when using quicklime production equipment instead of cement production equipment, superheated steam SS can be generated using exhaust gas from a production furnace. Moreover, in this case, as the substance containing CaO, defective products such as those having a particle size that is too small and those having a too low activity among the quicklime produced in the production furnace can be used.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to those structures, A various change is possible within the range of the invention described in the claim.

  For example, in the above embodiment, the case where the desalination apparatus of the present invention is used in combination with cement manufacturing equipment or quick lime manufacturing equipment has been described, but the equipment that is the other party of the composite contains a substance containing CaO in the manufacturing process. If it is the equipment to generate, it will not specifically limit.

  Moreover, in the 1st gas processing part 18, although the coarse powder D1 collect | recovered with the cyclone 11 of the chlorine bypass apparatus 3 is used as a substance containing CaO, it replaces with or adds to this, from the lowermost cyclone 7A of the preheater 7 The extracted bottom raw material (cement raw material mainly composed of CaO after passing through the calcined zone of cement kiln (850 ° C.)) can be used.

  Further, in the chlorine bypass device 3, after the coarse powder D1 is classified by the cyclone 11, the exhaust gas G2 containing the fine powder D2 is cooled and introduced into the bag filter 12, but the extraction extracted by the probe 10 without providing the cyclone 11. The gas G1 may be cooled and introduced into the bag filter 12. In this case, the dust collected by the bag filter 12 is used as the substance containing CaO to be introduced into the first gas processing unit 18 of the desalination apparatus 4.

DESCRIPTION OF SYMBOLS 1 Cement manufacturing factory 2 Cement baking apparatus 3 Chlorine bypass apparatus 4 Desalination apparatus 5 Cement kiln 6 Calciner 7 Preheater 7A-7D Cyclone 8 Kiln bottom 9 Cement raw material process 10 Probe 11 Cyclone 12 Bag filter 15 Waste heat boiler 16 Generator 17 Heating furnace 18 1st gas processing part 19 2nd gas processing part 20 Chimney D1 Coarse powder D2 Fine powder G1 Extraction gas G2-G7 Exhaust gas S Steam SS Superheated steam W Chlorine containing waste W 'Waste R after desalting Cement raw material

Claims (9)

Heating means for heating the chlorine-containing waste using waste heat discharged from the combustion furnace, and desalting the chlorine-containing waste;
A chlorine-containing waste desalination apparatus, comprising: a chlorine treatment means for bringing hydrogen chloride gas discharged from the heating means into contact with a substance containing CaO generated in the combustion furnace. Heating steam with waste heat of the combustion furnace, comprising superheated steam generating means for generating superheated steam,
The desalination apparatus for chlorine-containing waste according to claim 1, wherein the heating means heats the chlorine-containing waste with the superheated steam generated by the superheated steam generation means.   The combustion furnace is a cement kiln, and the substance containing CaO is dust collected by a chlorine bypass device attached to the cement kiln or a bottom material extracted from a preheater. Or the desalination apparatus of the chlorine containing waste of 2. The chlorine bypass device includes a probe for extracting a part of the combustion gas from the cement kiln exhaust gas passage from the bottom of the cement kiln to the lowermost cyclone, and a classifier for separating the dust dust from the extracted gas. Prepared,
The chlorine-containing waste desalination apparatus according to claim 3, wherein the substance containing CaO is coarse powder separated by the classifier.   The desalination apparatus for chlorine-containing waste according to claim 2, wherein the combustion furnace is a quicklime furnace, and the substance containing CaO is quicklime generated in the quicklime furnace.   6. The chlorine-containing waste desalination apparatus according to claim 1, wherein the heating means is a rotary kiln type heating furnace.   The desalination apparatus for chlorine-containing waste according to any one of claims 1 to 6, wherein the superheated steam generation means is a waste heat boiler. A desalination step of heating the chlorine-containing waste using waste heat discharged from the combustion furnace, and desalting the chlorine-containing waste;
A method for desalinating chlorine-containing waste, comprising: a step of bringing hydrogen chloride gas generated in the desalting step into contact with a substance containing CaO generated in the combustion furnace. Comprising the step of heating the steam with the waste heat of the combustion furnace to generate superheated steam;
The method for desalinating chlorine-containing waste according to claim 8, wherein in the desalting step, the chlorine-containing waste is heated by the superheated steam.

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