JP2005097464A - Particulate slag recovery equipment in organic waste gasification - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide particulate slag recovery equipment in organic waste gasification, which, through the installation of the particulate slag recovery equipment that can finely capture and discharge particulate slag in the state of slurry water discharged from the lower part of a slag settler, can efficiently separate particulate slag in the state of slurry water into process water and particulate slag. <P>SOLUTION: In the slag recovery step of the organic waste gasification plant 1, this equipment is featured in that the particulate slag slurry drawing-out line 59 is connected to the lower part of the slag settler 57 and the filter press 63 to filter the particulate slag slurry is installed downstream of the drawing-out line 59 and that, in the filter press 63, the outlet 67 to discharge the separated particulate slag is installed and the filtrate transferring line 65 to return the filtrate to the upper region of the slag settler is installed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an apparatus and method for satisfactorily collecting and discharging fine slag in a slag recovery process of an organic waste gasification plant.

  In recent years, a method has been proposed in which organic waste is gasified using a two-stage gasification apparatus to obtain synthesis gas. Here, the two-stage gasification processing apparatus is composed of an apparatus in which a low temperature gasification furnace 40 and a high temperature gasification furnace 1 are combined as shown in FIG. 1, for example, and the low temperature gasification furnace 40 includes a fluidized bed. The high-temperature gasification furnace 1 includes a combustion chamber 3 in which a combustible gas containing combustible carbonaceous particles is partially swirled while swirling inside, and a combustion chamber 3. A quenching chamber 25 having a double-pipe structure for cooling the generated synthesis gas and slag has a structure in which the combustion chamber 3 is disposed upward via the throat portion 9 and is integrally coupled in the vertical direction. It is a furnace (see Patent Document 1).

  In the quenching chamber 25, a slag discharge port 19, a generated gas take-out port 21, and a cooling water introduction port 15 are installed in the outer pipe. And as for the downcomer pipe 27 used as the inner pipe | tube of a double pipe structure, the lower edge part is buried in the stored water stored by the water tank part 31 of a quenching chamber lower part. In such a two-stage gasification processing apparatus, the molten slag generated in the combustion chamber 3 flows down the downcomer 27 and comes into contact with the stored water in the water tank portion 31 to become a granulated slag g. The granulated slag g generated in the water tank unit 31 is discharged together with the stored water from the slag discharge port 19, temporarily stored in the slag lock hopper 51, and then discharged. The slag screen 53 converts the slag g into the coarse slag k and the fine slag m. Sorted.

The separated fine slag m is supplied to the slag setra 57 in a slurry water state and subjected to solid-liquid separation (if there is a large amount of unreacted carbon, the temperature is lowered via a fine slag return line (not shown)). Supplied to the gasifier 40). The slurry containing fine slag supplied to the central part of the slag setra 57 is separated into solids and moisture while flowing from the central part to the outer peripheral part in the slag setra 57, and the clear water p separated in the upper region of the slag setra 57 Is supplied to the high-temperature gasification furnace 1 as cooling water i and supplied to the gas cleaning tower 55 as dust removal water s for reuse. Further, the fine slag m settled in the lower area of the slag setra 57 is discharged out of the slag setra 57 through a pipe disposed in the lower part of the slag setra 57 in a slurry water state having a relatively high solid content concentration. The slurry slag n in the slurry water state discharged out of the system is disposed of as it is, or is supplied to the low-temperature gasification furnace via the particulate slag return line, and the unreacted carbon is gasified by pyrolysis. (See Patent Document 2, See Patent Document 3, and Patent Document 4).
WO98 / 10225 Publication (Fig. 1-2) JP-A-11-166185 (page 5, FIG. 1) JP 11-33519 A (page 4, FIG. 1) Japanese Patent Laid-Open No. 2000-328071 (page 8, FIG. 5)

In the conventional apparatus, the fine slag is discharged out of the system in the slurry water state from the lower part of the setra and disposed as it is. At that time, the process water is also discharged out of the system together with the fine slag and is not recycled. Therefore, if we try to recycle this process water, it is not easy to separate the fine slag generated in the two-stage gasification treatment equipment, and stable separation is difficult, and the concentration of fine slag in the system increases, causing problems in various places (in the piping) This could cause pipe holes due to blockage or wear.
In addition, when supplying fine slag to the low-temperature gasification furnace, the fine slag concentration in the system will increase, and in order to adjust the fine slag concentration, the fine slag is eventually discharged from the lower part of the slag setra as described above. A similar problem was happening.

  Therefore, the present invention provides a fine slag recovery device that can satisfactorily collect and discharge the slurry slag discharged from the lower part of the slag settler, thereby efficiently converting the slurry slag into the process water and the fine slag. The separated process water can be recycled into the system to reduce the amount of water used, and fine slag can be discharged outside the system to stabilize the operation without increasing the concentration of fine slag in the system. An object of the present invention is to provide a fine slag recovery device in organic waste gasification.

  In the slag recovery process of the organic waste gasification plant, the fine slag slurry extraction line is connected to the bottom of the slag setra, and a filter press for filtering the fine slag slurry is provided downstream of the fine slag slurry extraction line. The filter press is provided with a discharge port for discharging the separated fine slag, and a filtrate transfer line for returning the filtrate to the upper area of the slag-settler. It is in the fine particle slag collection device in waste gasification.

  In the slag recovery process of the organic waste gasification plant, the present invention also extracts fine slag slurry from the bottom of the slag setra and filters it with a filter press to separate the fine slag and return the filtrate to the upper area of the slag setra. There is also a method for recovering fine slag in gasification of organic waste.

Next, preferable modes of the fine slag recovery device of the present invention will be listed.
(1) The fine particle slag recovery device in the above organic waste gasification, in which the filter cloth for ordinary filter plates is woven with monofilaments and the filter cloth for compressed filter plates is multifilament in the filter press.
(2) The fine particle slag recovery device in the above-mentioned organic waste gasification, wherein the warp of the filter cloth for the filter plate of the filter press is a monofilament and the weft is a multifilament.
(3) The fine particle slag recovery device in any one of the above organic waste gasification, wherein the filter cloth of the filter press is made of polypropylene.
(4) The fine slag recovery device in the above organic waste gasification using a filter press as a centrifuge.

  In the present invention, by installing a fine slag recovery device that can satisfactorily collect and discharge the slurry slag discharged from the lower part of the slag setra, the slurry slag can be efficiently converted into process water and fine slag. The separated process water can be recycled into the system to reduce the amount of water used, and fine slag can be discharged outside the system to stabilize operation without increasing the concentration of fine slag in the system. In addition, troubles such as blockage of the pipe due to fine slag and perforation of the pipe due to wear can be prevented.

Embodiments of a particulate slag recovery device in organic waste gasification of the present invention will be described with reference to FIGS. 1 to 3 of the accompanying drawings.
First, an outline of a two-stage gasification treatment apparatus for organic waste a will be described with reference to FIG.
In FIG. 1, a fluidized bed gasification furnace having a fluidized bed 42 and a free board 43 is used as a low temperature gasification furnace 40, and a swirl melting furnace having a combustion chamber 3 and a quenching chamber 25 is used as a high temperature gasification furnace 1. 2 shows a two-stage gasification treatment apparatus for a radioactive waste a.

Inside the low-temperature gasification furnace 40, the fluidized medium c fluidized by the fluidized gas b supplied from below the furnace forms a fluidized bed 42. As the fluidizing gas b, an oxygen-containing gas (oxygen gas, air, or a mixed gas thereof) is usually used. The oxygen gas and air supplied as the fluidizing gas b also act as a gasifying agent for the organic waste a. Water vapor may be further mixed with the gasifying agent.
The organic waste a supplied to the low temperature gasification furnace 40 is oxygen gas or air supplied into the furnace as a fluidizing gas and gasifying agent in the fluidized bed 42 maintained at a temperature of 450 to 850 ° C. Is quickly gasified by partial combustion to produce a combustible gas e. The amount of oxygen gas or air supplied as the fluidizing gas and gasifying agent is preferably 10 to 30% of the theoretical oxygen amount required to completely burn the organic waste a.

  From the bottom of the low-temperature gasification furnace 40, the fluid medium c is discharged together with the incombustible material d through the lock hopper 44, and the incombustible material d is removed by the screen 46. The fluid medium c from which the incombustible material d has been removed is returned to the inside of the low-temperature gasification furnace 40. The metal contained in the separated incombustible material d can be recovered in an unoxidized state by using the fluidized bed 42 as a reducing atmosphere.

  The combustible carbonaceous matter generated by the partial combustion of the organic waste a is finely pulverized by the agitating motion of the fluidized bed 42 and becomes a char accompanied by the flow of the combustible gas e. A part of the incombustible substance (ash content) is also finely pulverized by the agitating motion of the fluidized bed 42 and becomes particles and is accompanied by the flow of the combustible gas e.

  A combustible gas e containing incombustible substance particles and combustible carbonaceous particles (char) in a floating state is supplied to the combustion chamber 3 from the combustible gas inlet 5 of the high-temperature gasification furnace 1 and descends while swirling. To do. The combustible gas e (particularly hydrocarbon gas, combustible carbonaceous particles and tar) is partially burned by the oxygen-containing gas f supplied from the oxygen-containing gas inlet 13 and preferably also from the top oxygen-containing gas inlet 7. It is gasified to produce carbon monoxide gas and hydrogen gas. The temperature in the combustion chamber 3 is maintained at 1300-1500 ° C. by the combustion heat of the combustible gas e. When water vapor is contained in the oxygen-containing gas f (same as above), carbon monoxide gas and hydrogen gas are also generated by an aqueous gasification reaction between water vapor and combustible carbonaceous particles.

  The non-combustible substance particles contained in the combustible gas e become molten slag in the combustion chamber 3. Gas (gas mainly composed of carbon monoxide gas, carbon dioxide gas, hydrogen gas) and molten slag generated in the combustion chamber 3 and the molten slag are quenched in the quenching chamber 25, and the gas is generated from the product gas outlet 21 through the product gas h (synthetic gas). The molten slag becomes a granulated slag g and is taken out from the slag discharge port 19.

  The high temperature gasification furnace 1 includes a combustion chamber 3 and a quenching chamber 25 at a lower portion thereof via a throat portion 9. The combustion chamber 3 is provided with a flammable gas inlet 5 on the side and a plurality of oxygen-containing gas inlets 13 on the side for introducing a mixed gas of oxygen-containing gas and steam. Is also provided with a top oxygen-containing gas inlet 7 at the top. A cooling water inlet 15 is connected to the quenching chamber 25 along the outer surface of the upper part of the downcomer 27, and an annular overflow weir 23 for storing the cooling water i is disposed. The overflow weir 23 is configured such that the stored cooling water i can flow along the inner surface of the downcomer pipe beyond the overflow weir 23. Here, the cooling water i flows down the inner wall of the downcomer 27 while turning, and is stored in the water tank 31 at the bottom of the quenching chamber 25. In this stored water, the lower end of the downcomer 27 is buried.

  The carbon monoxide gas and hydrogen gas contained in the product gas h taken out from the product gas outlet 21 of the high-temperature gasifier 1 can be used as various chemical industrial raw materials. For example, the product gas h can be CO-converted to obtain hydrogen gas, which can be used as a hydrogen source for ammonia synthesis.

  On the other hand, the granulated slag g discharged from the slag discharge port 19 of the high-temperature gasifier 1 is sent to the slag recovery step. Here, the granulated slag g discharged from the slag discharge port 19 is collected by the slag lock hopper 51, extracted from the pressure system by the slag lock hopper system, and the coarse slag k is separated by the slag screen 53. It is pulled out of the system. On the other hand, the fine slag m that cannot be separated by the slag screen 53 is sent to the slag setra 57 and separated by settling. Further, a part of the cooling water containing the granulated slag g (slag slurry water j) is discharged from the slag slurry water outlet 17 at the upper part of the water tank 31 of the quenching chamber 25, and the generated gas h is removed from the bottom of the gas cleaning tower 55. Waste liquids containing slag after washing are respectively sent to the slag setra 57 and settled and separated.

In the slag-settler 57, most of the clarified water p in the upper region of the slag-settler 57 is recycled to the high-temperature gasification furnace 1 and the gas washing tower 55 and reused as the cooling water i and the dust removal water s. In addition, a part of the clarified water p is withdrawn to the wastewater treatment process in order to keep the chlorine concentration in the system below a predetermined value. The fine slag settled in the lower area of the slag setra 57 is discharged through a fine slag slurry extraction line 59 disposed in the lower part of the slag setra 57 in a slurry water state (fine slag slurry n) having a relatively high solid content concentration. When the slag in the discharged fine slag m or slag slurry water j contains a large amount of unreacted carbon, most of the fine slag m and slag slurry water j passes through a fine slag return line (not shown). And supplied to the low-temperature gasification furnace 40.
The above is the outline of the organic waste gasification processing apparatus.

Next, the fine particle slag collection | recovery apparatus in the organic waste gasification of this invention is demonstrated in detail.
2 to 3 are configuration diagrams of an example of an organic waste two-stage gasification treatment apparatus provided with the fine slag recovery device of the present invention in addition to the two-stage gasification treatment apparatus of FIG.

  The fine slag m settled in the lower area of the slag setra 57 is discharged in the state of relatively high concentration slurry water (as fine slag slurry n) through the fine slag slurry extraction line 59 connected to the lower part of the slag setra 57 and fed to the fine slag recovery device It is sent to the filter press 63 via the tank 61 and separated into fine slag m ′ and filtrate r. The fine slag m 'is discharged out of the system from the fine slag discharge port 67, and the filtrate r is returned to the upper region of the slag setra 57 via the filtrate transfer line 65 again. As a result, the fine slag m ′ can be reliably discharged out of the system and the increase in the fine slag concentration in the system can be suppressed, and troubles such as pipe blockage and perforation of the pipe due to the fine slag can be prevented. Furthermore, by recycling the filtrate r into the system, the supply of fresh water can be suppressed and reused as process water, which can contribute to cost reduction.

In the case of performing solid-liquid separation, in the filter press, in order to ensure separation of the fine slag m ′ and the filtrate r, the following filter cloth is preferably used.
That is, the filter cloth used for the filter press 63 is composed of a filter cloth for a normal filter board and a filter cloth for a compressed filter board (filter cloth for a filter board for compressing and dewatering fine slag cake), This normal filter cloth is preferably woven with monofilament, and the filter cloth for compressed filter is preferably woven with multifilament. Thereby, the fall of a collection capability can be prevented and the fine particle slag with an average particle diameter of 10 micrometers or less produced | generated in an organic waste gasification processing apparatus can be isolate | separated efficiently.
The filter cloth for the press filter plate is preferably multifilament (both warp and weft multifilament) as described above, but more preferably, the warp is monofilament and the weft is multifilament. This reduces clogging of fine slag, improves the peelability of the compressed fine slag cake from the filter cloth, and withstands the mechanical stress experienced by the filter cloth for the compressed filter plate, further increases the collection capability In addition, it is possible to prevent the collection ability from being lowered.

  Moreover, it is preferable that the material of the said filter cloth for normal filter plates and the filter cloth for press filter plates is a polypropylene. Thereby, it is possible to perform stable operation by suppressing the elongation of the yarn (that is, suppressing the opening) caused by passing the high-temperature fine slag slurry n of 70 to 90 ° C. through the filter press 63.

In the present invention, the filter press 63 may be the centrifuge 70.
That is, the fine slag m settled in the lower area of the slag setra 57 is discharged through the fine slag slurry extraction line 59 connected to the lower part of the slag setra 57 in a relatively high concentration slurry water state (as fine slag slurry n), and recovered fine slag. It is sent to the centrifuge 70 via the apparatus feed tank 61 and separated into fine slag m ′ and filtrate r. The fine slag m ′ is discharged from the fine slag discharge port 67 to the outside of the system, and the filtrate r is returned again to the upper region of the slag setra 57 via the filtrate transfer line 65. Thereby, the effect similar to the case of the said filter press is acquired.

Although the best mode for carrying out the invention has been described above, the present invention is not limited to this, and various modifications can be made without departing from the spirit of the present invention.

It is a block diagram of an example of the two-stage gasification processing apparatus of organic waste. It is a block diagram of an example of the two-stage gasification processing apparatus of the organic waste provided with the fine particle slag collection | recovery apparatus (filter press) of this invention. It is a block diagram of an example of the two-stage gasification processing apparatus of the organic waste provided with the fine particle slag collection | recovery apparatus (centrifuge) of this invention.

Explanation of symbols

1: High-temperature gasification furnace 3: Combustion chamber 5: Combustible gas inlet 7: Top oxygen-containing gas inlet 9: Throat part 13: Side oxygen-containing gas inlet 14: High-temperature gasifier inner layer castable 15: Cooling water Inlet 17: Slag slurry water outlet 19: Slag outlet 21: Generated gas outlet 23: Overflow weir 25: Quenching chamber 27: Downcomer pipe 29: Riser pipe 31: Water tank section 40: Low temperature gasifier 42: Fluidized bed 43: Free board 44: Lock hopper 46: Screen 51: Slag lock hopper 53: Slag screen 55: Gas cleaning tower 57: Slag setra 59: Fine slag slurry extraction line 61: Fine slag recovery device feed tank 63: Filter press 65: Filtrate Transfer line 67: Fine slag outlet 70: Centrifuge a: Organic waste b: Fluidized gas c: Fluid medium d: Incombustible material e: Flammable gas f: Oxygenated gas g: Granulated slag h: Product gas i: Cooling water j: Slag slurry water k: Coarse slag m: Fine slag m ': Fine slag slurry n: Fine slag slurry p : Clear water r: Filtrate s: Dust removal water

Claims (6)

In the slag recovery process of the organic waste gasification plant, a fine slag slurry extraction line is connected to the bottom of the slag setra, and a filter press for filtering the fine slag slurry is installed downstream of the fine slag slurry extraction line. The organic waste gas is characterized in that the filter press is provided with a discharge port for discharging the separated fine slag and a filtrate transfer line for returning the filtrate to the upper region of the slag-settler. Equipment for collecting fine slag in composting. 2. The apparatus for collecting fine slag in organic waste gasification according to claim 1, wherein in the filter press, the filter cloth for ordinary filter plates is woven with monofilaments and the filter cloth for compressed filter plates is woven with multifilaments. The apparatus for collecting fine slag in organic waste gasification according to claim 2, wherein the warp of the filter cloth for the filter press of the filter press is a monofilament and the weft is a multifilament. The apparatus for collecting fine slag in organic waste gasification according to claim 2 or 3, wherein the filter cloth of the filter press is made of polypropylene. The apparatus for recovering fine slag in organic waste gasification according to claim 1, wherein the filter press is a centrifuge. In the organic waste gasification plant slag recovery process, the organic slag is extracted from the bottom of the slag setra and filtered with a filter press to separate the fine slag and return the filtrate to the upper area of the slag setra A method for collecting fine slag in waste gasification.

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