JPH0674429A - Combustion and disposition of chlorine-containing combustible material - Google Patents

Abstract

PURPOSE:To increase the rate at which calcium is utilized and enhance the efficiency of dechlorination and desulfurization by a method wherein water slurry of a specific amount of calcium compound is mixed with a chlorine-containing combustible material and a combustor is loaded wit the mixture for combustion. CONSTITUTION:To burn a chlorine-containing combustible material 1 in a combustor 19 with a dust collector, to part or all of the combustible material 1 water slurry of a calcium compound 8, for which quicklime or slaked lime is preferable, is added in a manner that the number of moles of the calcium becomes one to three times the number of moles in the combustible material 1 (sulfur + 1/2 chlorine) and mixed. The combustor 19 is loaded with the resulting mixture. That is, a calcium compound 8 is put into a preparation tank 12 together with water 13 to form a slurry. On the other hand, the combustible material 1 is crushed by a crusher 6, put in a mixer 7 together with the slurry and mixed; then cured in a curing tank 15 and thereafter put into the combustor 19. Even for a smaller molar equivalent of a calcium compound against chlorine and sulfur, this method enables achieving a high rate of dechlorination.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for burning a combustible substance containing chlorine, and more particularly to a method for combusting the combustible substance at a high desalination rate.

[0002]

2. Description of the Related Art Conventionally, when combusting a chlorine-containing combustible material (hereinafter referred to as a combustible material) in a circulating fluidized bed combustor, it has been possible to suppress generation of HCl by adding limestone. As shown, when the particle size of limestone is large, a layer of reacted calcium chloride is formed on the surface of the limestone particle core, and there is a problem that the calcium compound in the unreacted core inside cannot be effectively used. Also, when the particle size of limestone is small, the limestone particles are not collected by the cyclone and lose the chance of being injected into the furnace again through the recirculation line below the cyclone, leaving unreacted convective heat transfer in the downstream part. There is also a problem that calcium carbonate cannot be effectively used because it passes through the surface and reaches the bag filter. Therefore, as shown in FIG. 4, calcium carbonate,
In any case of calcium hydroxide or a mixture of calcium hydroxide + calcium oxide, a desalting ratio of about 90% was obtained even when the molar ratio to sulfur + 1/2 chlorine was 3 times or more.

FIG. 2 shows an example of a conventional example of a combustible material-fired circulating fluidized bed boiler. The combustible material 1 is loaded into a combustible material receiving hopper 2 by a truck, conveyed from the receiving hopper 2 to a combustible material bunker 3 by a conveyor, and sent from below the bunker 3 to a combustible material bin 4 by a screw feeder. From the bin 4 through the combustible material feeder 5, compressed air is supplied to the circulating fluidized bed boiler combustor 19. The limestone 20 is loaded into the limestone silo 21 by a carrier,
It is thrown into the combustor 19 by the limestone transport blower 22. In the combustor 19, the combustible material burns, and the HCl gas generated from the combustible material 1 is formed due to desorption of CO ₂ gas as limestone particles forming a circulating fluidized bed throughout the combustor, as shown in FIG. The HCl gas that has penetrated into the macropores reacts on the surface layer of the CaO core, forming a CaCl ₂ layer on the surface layer of the unreacted core.

If the combustible material 1 also contains sulfur, SO ₂
The gas also reacts on the surface layer of the CaO core, forming a CaSO ₄ layer on the surface layer of the unreacted core. The solid particles, which have collapsed due to the progress of combustion and desalting reaction in the combustor 19 and have become sufficiently small, are not separated by the cyclone 23 and together with the combustion gas, the convection heat transfer section 38 on the downstream side, the air preheater. Three
After passing through 9, it reaches the bag filter 49 and is caught as fly ash.

The unbroken solid particles separated from the combustion gas in the cyclone 23 reach the seal pot 24, and are reintroduced into the combustor 19 by the seal pot blower 25. In this way, the unburned carbon in the solid particles is given an opportunity to burn in the combustor 19 over and over again.
Also, the solid particles collapse and become sufficiently small, and the cyclone 23
Combustor 19 with combustion gas
As long as it does not escape, all the surface layer of the unreacted core is CaCl
_It is used for desalination many times until it is covered with ₂ . Part of the particles separated by the cyclone 23 is the ash extraction control valve 2
Via 6 to a fluidized bed heat exchanger 27, where
The fluidized bed heat exchanger blower 28 exchanges heat with the boiler water and the boiler superheated steam to cool the boiler water and then the combustor 1 again.
It is thrown in 9.

The amorphous incombustible substance contained in the combustible substance 1 is taken out of the furnace by the foreign substance extraction pipe 29, cooled by the ash cooler 30, and then introduced into the cushion tank 31, where the screen 32 causes the fluid material to flow. Separated from
After being temporarily stored in the foreign matter silo 33, it is processed as the foreign matter 34. The fluid material from which foreign matter has been removed is stored in the bed ash silo 35, and when the fluid material is insufficient in the combustor 19, the bed ash transfer blower 36 again feeds the fluid material to the combustor 19 for reuse. If the fluid material is insufficient with these recycled fluid materials, sand 37 is used.

The air preheater 39 is of a steel pipe type, and the air pressurized by the fresh air fan 40 remains unchanged.
It is used as secondary air, but the primary air is the primary air blower 41.
Is further pressurized by and is guided to the wind chamber under the combustor 19.

The received slaked lime 43 and the special reaction aid 46 such as diatomaceous earth are stored in the slaked lime silo 44 and the special reaction aid silo 47, respectively, and then by the slaked lime transport blower 45 and the special reaction aid transport blower 48. The bag filter 49 is mixed with the flue gas from the upstream nozzle 42 and is widely used in the field of refuse incinerators to reach the bag filter 49 having the functions of desalting, desulfurization, dedioxin, demercury, etc. It is deposited on the upstream side of the furnace cloth, where hydrogen chloride, sulfur oxides, dioxins, metals such as mercury, etc. are removed from the exhaust gas together with fly ash, and stored in the fly ash silo 50.

A part of the fly ash is thrown into the combustor 19 by the blower 53 and recirculated. This makes it possible to re-burn unburned carbon in fly ash and reuse unreacted limestone for desalination, thereby improving desalination efficiency. The surplus fly ash is decomposed and removed by the dioxin thermal decomposition device 51 by dioxin transferred from the combustion gas into the fly ash by high temperature heating (about 300 ° C.) under the condition of oxygen limitation, and carried out as the fly ash 52. As for the gas that has passed through the bag filter 49, all the discharged substances are removed by the bag filter 49 below the allowable limit, and as a clean gas, the chimney 55 is drawn by the induced draft fan 54.
More discharged.

[0010]

The circulating fluidized bed combustion technology described above has many advantages such as being capable of burning a wide range of coal and industrial waste, and being capable of desalting and desulfurizing in a combustion furnace. Have Generally, Ca compounds such as limestone of several hundred μm to several mm are put into a combustion furnace for desalination and desulfurization. However, the desalination reaction and desulfurization reaction are limited to the vicinity of the particle surface of limestone, so the utilization rate of limestone is low. These calcium compounds are needed (see Figure 4 above). There is a problem that the use of excess calcium compound causes an increase in raw material cost and an increase in combustion ash treatment cost.

In view of the above-mentioned state of the art, the present invention intends to provide a combustion treatment method of a combustible material capable of highly efficient desalination and desulfurization by significantly increasing the utilization rate of Ca acting as a desalting agent and desulfurizing agent. It is what

[0012]

As described above, in fluidized bed combustion, the reason that the Ca utilization rate is generally low is that only the surface vicinity of the desalting agent particles is used for the reaction and the reaction does not proceed to the inside of the particles. (See FIG. 3). Therefore, in order to improve the utilization rate, it is necessary to use a desalting agent having a small particle size, but when the particle size is small, solid particles are not collected by the cyclone in the case of a circulating fluidized bed, and the desalting agent is used. Easily escapes from the inside of the combustor, and in the case of a bubble type fluidized bed, the desalting agent also easily escapes from the inside of the fluidized bed. Because it easily jumps out of
The residence time for the reaction in the furnace becomes short, and the desalination efficiency drops.

Therefore, in the present invention, a desalting agent is added to some or all of the combustibles before the combustion furnace is charged, and the desalting agent combustibles are mixed with other untreated combustibles as needed. The Ca utilization is improved by mixing, reacting, and burning.

That is, according to the present invention, (1) in a method of combusting a chlorine-containing combustible substance with a combustor having a dust collector in a downstream stream, a part or all of the combustible substance (sulfur + 1 / 2 chlorine), and after adding and mixing a water slurry of a calcium compound so as to be 1 to 3 times the number of moles of calcium, the mixture is put into a combustor and burned. Combustible content combustion treatment method.

(2) In the method of combusting a chlorine-containing combustible substance with a combustor having a dust collector in the downstream, a part or all of the combustible substance contains (sulfur + 1/2 chlorine) in the combustible substance. Chlorine-containing combustible material combustion treatment method, characterized in that a calcium compound and water are added and mixed so as to be 1 to 3 times the number of moles of the number of moles, and then the mixture is put into a combustor and burned. .

(3) The chlorine-containing combustible material combustion treatment method according to the above (1) or (2), wherein the mixture is aged for a predetermined time before being put into the combustor. Is.

The first invention of the present invention is a slurry preparation and mixing method. As shown in FIG. 5, this method prepares a slurry of a Ca compound, mixes it with a chlorine-containing combustible material, and optionally cures it. After burning, it is a method of burning. In FIG. 5, Ca compound 8 is put into preparation tank 12 together with water 13 to prepare a slurry. On the other hand, the combustible material 1 is crushed by the crusher 6, charged into the mixer 7 together with the slurry, mixed, and then cured in the curing tank 15, and charged into the combustor 19. When mixing the combustible substance 1 and the slurry Ca compound, particularly in the case of the water-repellent combustible substance 1 such as plastics and rubbers, it takes a curing time for the Ca compound to penetrate into the combustible substance 1. Crusher 6 for curing time
The particle size of combustible material 1 after crushing is also affected by.

As the Ca compound, quick lime, slaked lime, limestone and the like can be used. However, even if the slurry is prepared in advance, the solubility of limestone is almost nonexistent. It is preferable to adopt it when using.

The second invention of the present invention is a direct mixing method of Ca compounds, and this method also directly mixes Ca compounds, combustibles and water as shown in FIG. Is the way. In FIG. 5, Ca compound 8
The water is directly charged into the mixer 7 together with the water 14 and the combustible material 1 crushed by the crusher 6, mixed and then cured in the curing tank 15 and then charged into the combustor 19. As the Ca compound, limestone, quick lime, slaked lime and the like can be used, but it is a method that can be advantageously applied when limestone is used for the reasons described above.

The third invention of the present invention is a method for sufficiently permeating a Ca compound into a combustible material in the above first and second inventions. That is, when mixing a combustible substance with a solution or a slurry Ca compound, it takes time for the Ca compound to penetrate into the combustible particle, particularly in the case of a water-repellent combustible substance such as plastics and rubber. . The curing time is also greatly affected by the particle size of combustible material after crushing with a crusher. When the curing time is insufficient and the Ca compound does not penetrate into the combustible particles, the desalting efficiency naturally lowers.

From the above, the following curing conditions are preferable. (1) Curing time (a) When the particle size of the combustible material is several mm or more, it takes about 30 minutes to 2 to 3 hours. (B) About 5 minutes to 3 if the particle size of combustible material is several mm or less
It takes about 0 minutes. (C) However, there is a case where the Ca compound-added combustible bunker is held for a long time to also serve as a curing operation. (2) Curing temperature Since the solution or Ca in the form of slurry is mixed, the temperature is 100 ° C. or lower. However, in this temperature range, the reaction rate of Ca cannot be expected to improve, but the permeation effect can be expected to improve. However, since it takes energy to heat the combustibles and the slurry, high temperature is not preferable in consideration of economy.

[0022]

In the method of the present invention, depending on the types of combustible substances and Ca compounds, there are various states in which Ca compounds permeate into the combustible substances. These are collectively shown in FIG.

(1) Ion exchange action (mainly in the case of slaked lime and quick lime) It has ion exchange ability for carboxyl group, acidic hydroxyl group, sulfonic acid group and the like by either mixing method of slurry preparation or direct mixing method. Combustibles (eg coal,
Wastes such as papers, kitchen waste, fibers, wood, bamboos, plastics, and rubbers) in the presence of water, Ca ions are ion-exchanged and taken into combustible materials, Even after heating, it exists as Ca compound ultrafine particles of about 10 nm. The activity of such ultrafine particles is remarkably high, the utilization rate of Ca is 100%, and the reaction rate is extremely high.

(2) Impregnating action (mainly in the case of slaked lime and quick lime) Ca compound slurry is added to a porous combustible substance in the presence of water by either mixing method of slurry preparation or direct mixing method. In this case, the Ca compound is impregnated and taken into the combustible material. After heating, it exists as a sub-micron polycrystal, and the reaction activity is large after the ion exchange action.

(3) Slurry mixing action (in the case of all Ca compounds) A Ca compound slurry is added to a combustible material by a slurry preparation mixing method or a direct mixing method, or a slurry is generated in a mixer with the Ca compound and water. When sufficiently mixed, after heating, the Ca compound becomes fine particles of several μm to several tens of μm and seems to be dispersed in the combustible material, and the reaction activity also increases.

(4) Heat-melting and mixing action (in the case of all Ca compounds) When the combustible material contains a component that melts upon heating, it may be mixed by either a slurry preparation mixing method or a direct mixing method. Also, at the stage of being put into the combustor, the Ca compound is heated and melt-mixed by the combustible substance that is physically crushed in the pretreatment stage and melts at the time of heating, and is several μm to several 10 μm.
Will be taken into the combustibles as fine particles of
The reaction activity increases.

In any of the above actions, the Ca compound is incorporated into the combustible material as fine particles, so that the reaction activity is large. In addition, since the Ca-added combustible particles themselves can be handled in the same manner as ordinary combustible particles, a sufficient residence time in the fluidized bed, the fluidized bed or the combustor can be secured, and the handling of Ca particles is accompanied. There is no problem.

An embodiment in which the combustible material combustion treatment method according to the present invention is applied to a circulating fluidized bed boiler will be described below with reference to FIG. 1 to further clarify its operation. In the case of the slurry preparation and mixing method, the combustible material 1 is transferred by a truck to the combustible material receiving hopper 2
Be thrown into. A part of the combustible material is conveyed from the receiving hopper 2 to the crusher 6 by the conveyor and crushed, and the mixer 7
Is supplied to. Slaked lime 8 is carried into slaked lime silo 9.

The route from the slaked lime silo 9 to the mixer 7 is shown in FIG. 1 by a slurry preparation mixing method (shown by a portion surrounded by a broken line) and a direct mixing method (a portion surrounded by a one-dot chain line). ) Is different. In the case of slurry preparation and mixing method, the slaked lime exiting the slaked lime silo is screw conveyor 1
1 is supplied to the preparation tank 12. 9 in the preparation tank 12
Hot water 13 at 0 ° C. is supplied and becomes slaked lime slurry. The amount of Ca in the slaked lime slurry to the total amount of combustible substances 1 (sulfur + 1/2 chlorine) in the total amount of slaked lime slurry is kept in the range of 1 to 3 to the mixer 7, and crushed by the crusher 6. Mix with things. Further, it is kept and cured in the curing tank 15 for a certain period of time. In the case of the direct mixing method,
The slaked lime discharged from the slaked lime silo 9 has a molar ratio of Ca in the slaked lime to (sulfur + 1/2 chlorine) in the total amount of combustible substances 1
The amount of slaked lime that can be accommodated in the range of 3 to 3, together with the water 14 and the combustible material crushed by the crusher 6, is directly supplied to the mixer 7 and sufficiently mixed, and further held in the curing tank 15 for a certain period of time for curing.

In the mixer 7 and the curing tank 15, the slaked lime slurry prepared in advance in the combustible material 1 and the slaked lime slurry (in the case of the slurry preparation mixing method) or slaked lime and water in the mixer 7 (in the case of the direct mixing method). ), The Ca ion is ion-exchanged with a group having ion exchange ability such as a carboxyl group, an acidic hydroxyl group, and a sulfonic acid group in the combustible material 1,
It is taken into the combustible material and remains in the combustible material 1 as CaO ultrafine particles of about 10 nm even after the subsequent heating step. In addition, the slaked lime slurry prepared in advance in the preparation tank 12 (in the case of the slurry preparation mixing method) or in the mixer 7 (in the case of the direct mixing method) is impregnated into the porous portion of the combustible material 1 to make it combustible. It is taken in even inside the thing. Also, flammable materials 1
When has no ion-exchange group or porous portion,
Slaked lime slurry is mixed with combustible material 1 and heated to several μm to several 1
The particles become 0 μm and are dispersed in the combustible material 1.

In this way, Ca is mixed in the mixer 7 and the curing tank 15.
The Ca compound-added combustible material that is physically and chemically mixed with is supplied to the Ca compound-added combustible material bunker 16, passes through the Ca compound-added combustible material bin 17, passes through the feeder 18, and is fed into the combustor 19.

The case where the Ca compound is added to the total amount of the combustible material targeted for the above is explained above.
A Ca compound is added by a mixer 7 so that the ratio to (sulfur + 1/2 chlorine) in the mixture becomes a Ca molar ratio of 1 to 3 or more, and the mixture is sent from the chlorine-containing combustible material bunker 3 to the combustible material bottle 4. The burned combustible material 1 to which the Ca compound is not added may be supplied to the combustor 19 via the combustible material feeder 5 together with the desalting agent-containing combustible material to which the Ca compound is added in excess and supplied from the feeder 18. In this case, the mixing ratio of both should be adjusted so that the molar ratio of Ca to (sulfur + 1/2 chlorine) in the combustible substance is in the range of 1 to 3 in macroscopic view.

When the combustible material contains a component that melts when heated, it is added to the combustor 19,
The Ca compound-added combustible substance is physically crushed in the pretreatment stage, and the Ca compound is thermally fused by the combustible substance that melts when heated, and the Ca compound is incorporated into the combustible substance as fine particles.

In the combustor 19, the combustible material 1 burns, and the HCl gas generated from the combustor 1 is generated from the Ca compound particles incorporated in the Ca compound-added combustible material forming a circulating fluidized bed over the entire combustor 19. , Reacts on the surface layer of Ca compound particles to form a CaCl ₂ layer. When the combustible material 1 also contains a sulfur content, SO ₂ gas also reacts on the surface layer of the Ca compound to form a CaSO ₄ layer. The Ca compound-added combustible material contains a Ca compound having a molar ratio of 1 to 3 with respect to (sulfur + 1/2 chlorine) contained in the entire chlorine-containing combustible material 1. This C
Among the a compounds, the fine Ca compounds that have been combusted in the combustor 19 and collapsed with the progress of the desalting reaction and taken into the combustible material particles that have become sufficiently small are not separated even by the cyclone 23 and together with the combustion gas. After passing through the convection heat transfer section 38 and the air preheater 39 on the wake side, it reaches the bag filter 49 and is caught as fly ash.
However, it does not contribute to the desalination or desulfurization reaction in the convection heat transfer section 38, the air preheater 39, and the bag filter 49. However, since most of the surface layer portions of these particles have a small particle size of the fine Ca compound taken into these particles, the desalting or desulfurization reaction is completed within the time when these particles disintegrate in the combustor 19. Since the particle size is small and the unreacted cores other than the surface layer are small, the unreacted Ca compound at the exit of the combustor 19 is small.

The undecomposed combustible material particles separated from the combustion gas by the cyclone 23 and the particles incorporating the fine Ca compound reach the seal pot 24, and the seal pot blower 2
5 re-enters the combustor 19. Thus
The unburned carbon in the combustible particles is given a chance to be burned in the combustor 19 over and over again, and the combustible solid particles are collapsed and become sufficiently small.
Combustor 19 with combustion gas
Fine Ca captured in combustibles as long as it does not escape
The compound is repeatedly desalted until the entire surface of the compound is covered with CaCl ₂ . As described above, in the present invention, since the Ca compound particles incorporated in the solid particles of the combustible material are fine, the unreacted core portion inside the surface layer portion is very small, and the Ca compound particles are substantially 100% compound
Since it can be used in the vicinity, the Ca compound has a molar ratio of Ca to (sulfur + 1/2 chlorine) of 1 to 3, but the desalination rate is extremely high as described in the following examples. The ash extraction control valve 26 in FIG.
Since the operation of the parts up to 5 is the same as that of the conventional system shown in FIG. 2 already described, the description thereof is omitted here.

[0036]

EXAMPLES Next, examples of the present invention will be described. Table 1 shows examples and comparative examples. Example 1 [Slurry Preparation and Mixing Method] In FIG. 1, as the combustible material, industrial waste (containing coal cinder, waste plastic, rubber, etc.) containing 2.7 wt% chlorine and 1.4 wt% sulfur was used. . Slaked lime 8 (average particle size 25 μm) after passing through a 325-mesh sieve is supplied to a preparation tank 12 holding hot water at 90 ° C. to obtain slaked lime slurry, which is combustible with a crusher 6 and a mixer 7. After mixing, circulating fluidized bed boiler combustor 1
Burned at 9. As a result of analysis of exhaust gas and residues of the combustion furnace, the desalination rate was 80% although the slaked lime molar ratio {Ca / (S + 0.5Cl)} was only 1.

When this result is compared with Comparative Example 1 described below in which limestone and combustibles are directly charged into the furnace, when Ca compounds are directly mixed into the combustibles and the limestone is directly charged into the furnace. Compared with the molar ratio {Ca / (S + 0.5
Cl)} was the same, but a desalination rate of about 4 times was obtained. This is because when limestone is directly charged into the furnace, chlorine in the combustible material reacts only with the surface of limestone, whereas in the case of slaked lime slurry, it is a very fine CaO of several 10 nm to several 10 μm. The result is that the permeation into the combustibles did not occur and there was no unreacted core, and the reaction rate with chlorine was improved.

(Example 2) (Slurry adjusting / mixing method) In the same manner as in Example 1, the amount of added water was changed and combustion was carried out in the circulating fluidized bed boiler combustor 19. As a result of analysis of exhaust gas and residues of the combustion furnace, slaked lime molar ratio {C
Although a / (S + 0.5Cl)} is the same as in Example 1, the desalination rate was 90%, which was higher than that in Example 1. This is because, as compared with Example 1, by increasing the water content, the ion exchange and the impregnation action into the pores become remarkable,
This is because of the improved desalination rate.

Example 3 (Slurry Preparation and Mixing Method) In the same manner as in Example 1, combustibles were burned in the combustor 19 of the circulating fluidized bed boiler under different slurry conditions. As a result, although the slaked lime molar ratio {Ca / (S + 0.5Cl)} was 3, the desalination rate was 99.8% or more (substantially 100%). In this case, since the HCl concentration at the bag filter inlet was below the detection limit, this expression was used. In this case, since the HCl concentration at the bag filter inlet is already below the detection limit, it is not necessary to inject slaked lime 43 from the nozzle 42 upstream of the bag filter.

Comparing this result with the result of Comparative Example 2 which will be described later, by mixing slaked lime slurry with a chlorine-containing combustible substance, a molar ratio of Despite the same Ca / (S + 0.5Cl)}, a desalination rate of about 1.4 times was obtained. Compared with Example 1, the desalination ratio was improved because the molar ratio of slaked lime was increased.

When the molar ratio is increased to 3 or more, the desalting ratio is increased to some extent even if the conventional method is used, so that the effect of the present invention becomes relatively small. Further, in general, it is not economical to increase the molar ratio to 3 or more in the present invention because of the increase in the Ca compound cost required for increasing the molar ratio and the resulting processing cost of the combustion ash.

(Example 4) (Slurry preparing and mixing method) As in Example 1, slaked lime 8 was supplied to a preparation tank 12 holding hot water at 90 ° C to prepare a slaked lime slurry. The combustible material crushed by the crusher 6 was mixed with the mixer 7, and the mixture was further held in the curing tank 15 at 38 ° C. for 1 hour and then burned in the circulating fluidized bed boiler combustor 19. As a result of the analysis of the boiler exhaust gas and the residue, the desalination rate was found to be slaked lime molar ratio {Ca /
Although (S + 0.5Cl)} was 1, which was the same as in Example 1, the desalination rate was 90%, which is higher than that in Example 1.
This is the effect of curing after mixing.

(Example 5) (Direct mixing method) Slaked lime 8 prepared in the same manner as in Example 1 was crushed by a crusher 6 with a mixer 7 while adding a small amount of water 14 to a waste plastic having heat melting property (polyester). After mixing with industrial waste (containing 3.0 wt% of chlorine and 1.2 wt% of sulfur) containing (including vinyl chloride, polyethylene, etc.), it was burned in the circulating fluidized bed boiler combustor 19.

As a result of analysis of boiler exhaust gas and residues, a desalination rate of 50% was obtained, which was about 2.5 times that of Comparative Example 1 described later, although the molar ratio was the same. This is because the component that melts during heating causes the Ca compound as fine particles to be incorporated into the combustible material by heating, melting and mixing, and the Ca compound becomes fine particles.

Example 6 (Direct Mixing Method) The same combustible material as in Example 5 was used, limestone having an average particle size of 40 μm was used instead of slaked lime, and the combustible material was circulated in a circulating fluidized bed by the same operation. It burned in the boiler combustor 19.
As a result of analysis of boiler exhaust gas and residues, Comparative Example 1 described later
Compared with the above, a desalination rate of 37%, which was about 1.7 times, was obtained, although the molar ratio was the same 1. This is because the component that melts during heating causes the Ca compound to form a fine particle into the combustible material by heating, melting and mixing, and the Ca compound becomes a fine particle. Compared with Example 5, the desalination rate is low even though the molar ratio is 1, which is because the reactivity of limestone is lower than that of slaked lime.

(Example 7) (Direct Mixing Method) The same combustible material as in Example 5 was used, and limestone having an average particle size of 490 μm was used in place of slaked lime.
The combustible material was burned in the circulating fluidized bed boiler combustor 19. As a result of analysis of boiler exhaust gas and residues, a desalination ratio of 31%, which is about 1.5 times, was obtained as compared with Comparative Example 1 described later, although the molar ratio was the same 1. This is because the component that melts during heating is heated and mixed by mixing the Ca compound into the combustible material as fine particles, and the Ca compound becomes fine particles. Compared with Example 6, although the molar ratio is the same 1, the desalination rate is low because the average particle size is large and the reactivity is low.

Although the above embodiments have been described with reference to examples applied to a special circulating fluidized bed combustion apparatus, the present invention is similarly applied to other types such as a bubble type fluidized bed boiler or combustion furnace, a stoker type boiler or a combustion furnace. Of course, can be applied.

Comparative Example 1 Limestone was directly charged into a circulating fluidized bed boiler combustor and burned with the same chlorine-containing combustible material as in Example 1. As a result of the exhaust gas and residues of the combustion furnace, the desalination rate was 21%.

Comparative Example 2 Limestone was directly charged into a circulating fluidized bed boiler combustor and burned with the same combustible material as in Example 1. As a result of the exhaust gas and residues of the combustion furnace, the desalination rate was 80%.

In the above comparative examples, only limestone was used, but even if quicklime or slaked lime was used, the desalination rate was about the same. Quick lime and slaked lime have better desalination action than limestone, but generally they are differentiating compared to limestone, so the residence time in the combustor is short, and the desalination rate is similar to that of limestone. .

[0051]

[Table 1]

[0052]

As described above, conventionally, in order to obtain a high desalination rate, it is necessary to increase the molar equivalents of chlorine and sulfur of Ca compounds to be introduced into a combustor such as a circulating fluidized bed boiler together with a chlorine-containing combustible substance. However, according to the present invention, even if the molar equivalent of chlorine and sulfur of the calcium compound is small, it is possible to obtain a high desalination rate, and it is difficult to incinerate industrial waste containing high chlorine, etc. It has become economically possible to burn the combustible substances.

[Brief description of drawings]

FIG. 1 is a system diagram of a chlorine-containing combustible material-fired circulating fluidized bed boiler plant according to an embodiment of the present invention.

FIG. 2 is a system diagram of a chlorine-containing combustibles-fired circulating fluidized bed boiler plant according to an example of a conventional technique.

FIG. 3 is a schematic diagram of a desalination process of a calcium compound in a circulating fluidized bed boiler combustor.

FIG. 4 is a diagram showing the relationship between the calcium molar ratio input and the desalination rate in a chlorine-containing combustibles-fired circulating fluidized bed boiler according to a conventional technique.

FIG. 5 is an explanatory view of a method of adding a calcium compound in the method for burning a chlorine-containing combustible material of the present invention.

FIG. 6 is an explanatory view of the action (phenomenon and reaction) of the chlorine-containing combustible material combustion treatment according to the present invention.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yasuyuki Takarada 3535-3, Hishimachi, Kiryu-shi, Gunma Prefecture (72) Inventor Toshio Haneda 2-5-1, Marunouchi, Chiyoda-ku, Tokyo Sanryo Heavy Industries Co., Ltd. (72) Inventor Naoyoshi Oda 2-5-1, Marunouchi, Chiyoda-ku, Tokyo Sanryo Heavy Industries Co., Ltd. (72) Inventor Shinai Koizumi 2-5-1, Marunouchi, Chiyoda-ku, Tokyo Sanryo Heavy Industries Co., Ltd. In-house (72) Inventor Yukihisa Fujima 5-717-1, Fukahori-cho, Nagasaki-shi, Nagasaki Sanryo Heavy Industries Co., Ltd.Nagasaki Research Institute (72) Inventor Yoshiyuki Takeuchi 4-62, Kannon-shinmachi, Nishi-ku, Hiroshima-shi Mitsubishi Heavy Industries Hiroshima Laboratory Co., Ltd.

Claims (3)

[Claims] 1. A method of combusting a chlorine-containing combustible substance in a combustor having a dust collector in a downstream thereof, wherein a part or all of the combustible substance contains (sulfur + 1/2 chlorine).
After adding and mixing the water slurry of the calcium compound so as to be 1 to 3 times the number of moles of calcium with respect to the number of moles of
A method for burning a combustible substance containing chlorine, wherein the mixture is put into a combustor and burned. 2. A method of combusting a chlorine-containing combustible substance with a combustor having a dust collector in the downstream, in which a part or all of the combustible substance contains (sulfur + 1/2 chlorine).
Chlorine-containing combustible material combustion treatment characterized by adding and mixing a calcium compound and water so that the calcium content is 1 to 3 times the molar number of Law. 3. The chlorine-containing combustible material combustion treatment method according to claim 1 or 2, wherein the mixture is aged for a predetermined time before being charged into the combustor.