WO2005093014A1 - Method for removing tar in fluidized layer furnace - Google Patents

Abstract

A method for removing tar in a fluidized layer furnace which comprises subjecting, in a system wherein a raw material is gasified, pyrolyzed or partially oxidized to form an objective gas, a tar formed from the raw material to the adsorption and decomposition by the use of a fluidized cracking catalyst, a fluidized cracking equilibrium catalyst, silica-alumina based particles or alumina based particles prepared by the oil immersion granulation method, and/or to the attachment to a fluidized cracking catalyst, a fluidized cracking equilibrium catalyst, silica-alumina based particles or alumina based particles prepared by the oil immersion granulation method and to burning.

Description

 Method of removing tar in fluidized bed furnace

 Technical field

 The present invention relates to a method for removing tar in a fluidized bed furnace in a system for gasifying fossil fuels such as coal and heavy oil, biomass, and the like to generate a fuel gas and a chemical raw material gas.

 Background art

 [0002] Gasifiers for coal and the like are roughly classified into three types: a spouted bed gasifier, a fluidized bed gasifier, and a fixed bed gasifier. In the fluidized bed coal gasifier, coarse pulverized coal with an average particle size of 16 mm is used. In this method, pulverized coal is fluidized by oxygen or air, which is a gasifying agent, and water vapor, and conversion into CO, CO, and H proceeds in the furnace. Flow

 twenty two

 Coal gasification using a bed generates tar when the reaction temperature decreases, causing handling trouble in the process. Therefore, in the prior art, the gasification temperature has been higher than 900 ° C. In addition, the use of limestone and alumina as catalysts for decomposing tar has been studied.

 [0003] Tar treatment methods in fluidized bed gasification include (1) a method in which the gasification temperature is raised to 900 ° C or more, and (2) a tar decomposition catalyst component such as nickel molybdenum is charged or fluidized into a furnace. (3) A adsorptive substance such as alumina, zeolite, limestone, etc. is placed in the furnace, or is charged as a fluid medium, adsorbs tar, and is decomposed in a regeneration furnace such as a combustion furnace. Methods have been studied.

[0004] However, the method (1) reduces the cold gas efficiency and increases energy loss, and the method (2) requires a price of nickel molybdenum used as a decomposition catalyst component impregnated into particles such as alumina. Is expensive, and the particles are easily crushed due to wear due to fluidization of the particles, and the gasification furnace power is also scattered outside the system, or the decomposition effect is reduced due to the carbon content precipitated on the particle surface. Therefore, the method (3), which requires the replenishment of particles and is less economical, regenerates particles by decomposition and combustion of carbon and other substances by using adsorbent particles such as alumina and zeolite without using expensive decomposition catalysts. To some extent, but adsorbable particles • The carbon content resolution is low, and the fine particles are granulated.

 As described above, in the current method of treating tar, it is the reality that the demand for producing energy at low cost is met.

 [0005] The present invention has been made in view of the above circumstances, and has as its object to provide an excellent method for removing tar in a fluidized bed furnace. Another object of the present invention is to provide a method for removing tar in a fluidized bed furnace having high cold gas efficiency.

 Disclosure of the invention

 [0006] The present inventors have conducted intensive studies to achieve the above object, and as a result, in order to improve cold gas efficiency, set the gasification temperature to a low temperature (for example, 600 ° C or more and less than 900 ° C). A system that adsorbs and decomposes tar generated during low-temperature gasification using adsorbent particles in the furnace, and regenerates Z or carbonaceous materials attached to the particle surface in a regeneration furnace such as a combustion furnace. In, specific adsorbent particles, for example,

 (i) Specific alumina-based particles, silica'alumina-based particles or silica-based particles that combine high tar, adsorption and resolution, and powder resistance in the furnace due to fluidization (poor powdering rate)

 (ii) The present inventors have found that the use of specific clay-based mineral-based particles having both a tar adsorption ability and an extremely high and high resolution can achieve both adsorption, resolution and economy, and completed the present invention.

 [0007] According to a first aspect of the present invention, in a system in which a raw material is gasified, thermally decomposed, or partially oxidized in a fluidized bed furnace to obtain a product gas, tar generated from the raw material is subjected to fluid catalytic cracking. Catalyst, fluid catalytic cracking equilibrium catalyst, adsorbs and decomposes using silica-alumina-based particles or alumina-based particles produced by oil immersion granulation, and z or fluid catalytic cracking catalyst, fluid catalytic cracking equilibrium catalyst, Provided is a method for removing tar in a fluidized bed furnace, which comprises attaching and burning silica-alumina-based particles or alumina-based particles produced by an oil immersion granulation method.

[0008] According to a second aspect of the present invention, in a system in which a raw material is gasified, thermally decomposed, or partially oxidized in a fluidized bed furnace at less than 900 ° C to obtain a product gas, the raw material power is also generated. Adsorbed particles to adsorb and decompose the tar, and adhere to Z or adsorbent particles for combustion A method for removing tar in a fluidized bed furnace is provided.

 According to the present invention, an excellent method for removing tar in a fluidized bed furnace can be provided. Further, it is possible to provide a method for removing tar in a fluidized-bed furnace having high cold gas efficiency.

 Brief Description of Drawings

 FIG. 1 is a schematic diagram of a publishing type fluidized bed gasification furnace.

 BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described. In the present invention, “fluidized bed” is synonymous with “fluidized bed”.

 The raw material used in the method of the present invention is not particularly limited, and for example, fossil raw materials such as petroleum, coal, and coats, waste, biomass, and the like can be used. Among these raw materials, biomass, particularly woody biomass, is preferred.

 [0011] In the method of the present invention, the fluidized bed furnace is not particularly limited. For example, a fluidized bed furnace that processes a publishing type fluidized bed, an external / internal circulation type fluidized bed, a pressurized type / normal pressure type fluidized bed, or the like is used. Can be. Preferably, it is a fluidized bed furnace using a publishing type fluidized bed as a process. In these fluidized bed furnaces, conditions for gasifying, thermally decomposing, or partially oxidizing the raw material can be appropriately adjusted according to the type of the raw material and the like.

 [0012] In the present invention, it is preferable that the raw material is gasified at a low temperature. Preferably, it is gasified at a low temperature of less than 900 ° C, more preferably 850 ° C or less. Further, it is usually gasified at a temperature of 500 ° C or higher, preferably 550 ° C or higher. By treating the raw material at such a low temperature, the cold gas efficiency can be increased.

 Gasification at low temperatures causes tar problems, but the present invention can address this problem by using adsorbent particles.

 [0013] In the method of the present invention, tar produced by the above-mentioned raw material power is adsorbed and decomposed using adsorptive particles to remove tar.

Here, examples of the adsorptive particles include fluid catalytic cracking catalyst (FCC catalyst) particles, fluid catalytic cracking equilibrium catalyst (FCC equilibrium catalyst) particles, silica-alumina particles, and alumina produced by an oil immersion granulation method. Based particles (porous alumina, activated alumina, γ-alumina, activated bokeh Site), silica-based particles such as silica gel, raw concrete sludge and its sludge cake, particles of lime cake, concrete, concrete structures and waste of concrete structures, and clay mineral particles such as activated clay, zeolite, and sepiolite. And the like. In the present invention, the adsorptive particles include used adsorptive particles or a catalyst containing the adsorptive particles.

 [0014] The used catalyst means a catalyst used in a process that is the original purpose of the catalyst such as a desulfurization reaction of petroleum fraction and discarded due to a decrease in desulfurization reaction activity and the like. These used catalysts can be used as they are, or they can be used by burning and regenerating adhering carbonaceous materials, and by washing and removing precipitated metal components with an acid or the like. Monkey

 [0015] Among these adsorptive particles, FCC catalyst particles, FCC equilibrium catalyst particles, silica-alumina-based particles, and alumina-based particles produced by an oil immersion granulation method are preferable. In particular, porous alumina or activated alumina produced by an oil immersion granulation method is preferable. By using these as the adsorptive particles, the powdering rate at the time of fluidization can be reduced and the adsorbing / resolving power of tar can be increased as compared with the prior art.

 The oil immersion granulation method is a method of immersing mainly hydroxylated aluminum converted into a hydrogel in a heated roll bath and granulating into spherical particles by surface tension.

 [0016] The fluid catalytic cracking catalyst (FCC catalyst) is a catalyst for catalytically cracking heavy oil (such as vacuum gas oil or atmospheric residual oil) to produce gasoline with a high octane number. Metal oxides such as silica 'alumina, titanium, and alumina' titanium; clay minerals such as kaolin and bentonite; various zeolites; 'Examples include porous particle FCC catalysts prepared by a method such as spray drying using alumina, rare earth-substituted Y zeolite, kaolin, or the like.

 [0017] Fluid catalytic cracking equilibrium catalyst (FCC equilibrium catalyst) is a catalyst that is periodically withdrawn when the catalytic activity of the FCC unit becomes constant. Etc.), the metals such as iron, vanadium and nickel accumulated on the above FCC catalyst.

Preferably, vanadium and Z or nickel on the particle surface are 500-15000 mass ppm Particularly preferred are FCC equilibrium catalysts that have accumulated FCC and have a vanadium and / or Z or nickel accumulation of 800-5000 ppm by mass!

 Generally, in a fluid catalytic cracking unit (FCC unit) for producing gasoline having a high octane number, a new catalyst is added at appropriate times in order to keep the activity of the FCC catalyst constant. It is completely mixed with a certain catalyst, and the activity of the catalyst will be averaged. However, since the amount of catalyst in the equipment would be excessive if it was not used, a certain amount was always extracted.

 In the present invention, tar can be adsorbed and decomposed by pre-filling these adsorbed particles in a fluidized-bed furnace or charging them into a fluidized-bed furnace.

In the present invention, tar can also be adsorbed and decomposed by using these adsorbed particles as a fluid medium and a circulating medium (circulating solid) of a fluidized bed furnace.

[0020] In the present invention, when using a fluidized bed furnace that processes a publishing type fluidized bed and an internal circulation type fluidized bed, these adsorptive particles can be used as a fluidized medium.

 On the other hand, when a fluidized bed furnace using an external circulation type fluidized bed as a process is used, these adsorptive particles can be used as a circulating medium.

Further, in the present invention, by scattering these adsorptive particles from the fluidized bed, tar can be adsorbed and decomposed in a fluidized bed furnace (for example, a freeboard portion or the like). The conditions for scattering the adsorptive particles can be appropriately adjusted according to the type of the fluidized bed and the adsorptive particles.

 [0022] In the method of the present invention, tar produced by the above-mentioned raw material force is attached to the above-mentioned adsorptive particles and burned, whereby tar can be removed. The combustion of the attached tar can be performed in the combustion zone in the fluidized bed furnace.

 In the present invention, the tar can be continuously removed by adsorbing and decomposing the tar using the adsorptive particles and further burning the adhered tar remaining without being decomposed by the adsorptive particles. it can. In the present invention, since the adsorbable particles are regenerated in the combustion region by the combustion of the attached tar, the adsorbable particles can be used continuously.

The method of the present invention is efficient because the heat of combustion can be used as a gasification heat source. In addition, gasified gas generated by the combustion of raw materials and fuel generated by the combustion of tar Since the combustion gas is separated, the gasification gas becomes a high-calorie gas.

 [Example]

 Next, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

 [Experimental Apparatus and Method]

 A lab-type publishing type fluidized-bed gasification furnace 1 shown in FIG. 1 was used. This apparatus 1 is composed of a gasifier 2, a dispersion plate 4, and a wind box 6. This apparatus 1 is cylindrical and made of stainless steel with an inner diameter of 100 mm and a height of 1.5 m (the disperser 4 is also up to the furnace outlet 8). Outside the device 1, an electric furnace 10 for controlling the gasification temperature is installed. Nitrogen gas is used as the gasification gas at a flow rate of 6 liters Z, from the gas inlet 12 through the gas preheater 14 equipped with a gas preheating function, the wind box 6, and the disperser 4, Feeded to 2.

 The apparatus 1 was previously filled with particles (particles A to E) having a height of 150 mm as a fluid medium 16 on a dispersion plate 4. The fluid medium 16 flows and scatters inside the gasification furnace 2 by the gas gas supplied through the dispersion plate 4.

 After the inside of the gasification furnace 2 is heated to a predetermined temperature (600 ° C., 700 ° C., 800 ° C.) by an electric furnace 10 provided outside, a raw material feeder 18 provided outside the apparatus 1 is heated. The raw material and the particles were supplied quantitatively from the feeder and the particle feeder 20, respectively. The gasified product gas and tar are discharged to the outside through the furnace outlet 8 at the upper part of the gasification furnace, and a part of the gas and tar is introduced into the organic solvent (ethanol) for tar recovery in the tar recovery unit 22. , Completely recovered. The amount of the collected tar sample was measured by a combination of GC-FID and desolvation residue method.

 The raw material is wood biomass (cedar: carbon content 48.7%, hydrogen content 5.8%, oxygen content 40.2%, ash content 0.4%, moisture 4.9%), particle size 200—300 / zm And supplied at a flow rate of 5 gZ. The total amount of the fluid medium particles was adjusted to a particle size of lmm or less and supplied at a flow rate of 60 gZ.

 [0027] The following particles A to E were used as the fluid medium particles.

 Particle A: Alumina particles produced by the oil immersion granulation method

 Production method: Aluminum sulfate aqueous solution (AI O: 7.72%) in a 20L stainless steel container

 2 3, S

O: 18.20%), weigh 16 kg of sodium aluminate aqueous solution (AI O: 23.80%, Na (0: 19.10%) 4. 28 kg was weighed into a 5 L stainless steel container.

 Next, the injection rate of the aqueous solution of aluminum sulfate was set to about 102 mlZmin, and the injection rate of the aqueous solution of sodium aluminate was set to 23.3 mlZmin. The mixture was simultaneously mixed with a metering pump under high shear.

 Furthermore, the target basic aluminum sulfate hydrosol molar ratio (SO ZA1 O) is 0.9

 3 2 3

A circulating system of the mixture was formed under high shear so as to obtain 2, and 546 g of an aqueous solution of sodium aluminate was added thereto and mixed at an injection rate of 2. OmlZmin.

[0028] The circulation speed was 800 ml Zmin, and the mixture was aged at room temperature for 7 days with stirring. Finally Al O concentration

 23 degrees 11.44%, pH 3.97, viscosity 180m.pa.s, 70. A Genolei dangling time in C was 5 minutes, and a hydrosol of basic aluminum sulfate of 40 min was obtained. The molar ratio of the basic aluminum sulfate hydrosol (SO 2 / Al 2 O 3) was 0.922.

 3 2 3

 [0029] The prepared basic aluminum sulfate hydrosol is further aged for 20 days at room temperature with stirring and aging to promote polymerization and increase the viscosity of the basic aluminum sulfate hydrosol to prepare a concentrated ammonia monosalt in advance. PH buffer solution of ammonium chloride (NH Cl: 70g and concentrated

 Four

Approximately 500 ml of aqueous ammonia was ion-exchanged and hydrogenated, and the basic aluminum hydrosol was extruded with a syringe into a buffer solution (pH 9.84), adjusted to a total volume of 1 liter, and hydrogelated at room temperature. A columnar transparent alumina hydrogel was prepared. After washing with water and drying, it was calcined at 600 ° C. for 3 hours to obtain transparent activated alumina particles. The crystalline state of the particle A (600 ° C. for 3 hours) is amorphous, the BET specific surface area is 274 m ² Zg, and the pore area is 0.37 ml / g.

 [0030] Particle B: silica 'alumina particles (Neobead SA manufactured by Mizusawa I-Dagaku Kogyo Co., Ltd.)

[0031] Particle C: FCC equilibrium catalyst

Production Method: real device forces also withdrawn vanadium 520 ppm by weight and nickel 28 0 mass ppm rhenium accumulated substituted ultrastable Y-type zeolite of 10 mass FCC _^0/0, alumina 40 wt%, silica 30 wt% and clay minerals Kaolin consisting of 20% by mass was used.

[0032] Particle D: Limestone (made by Taiheiyo Cement, crushed product of 1 mm or less)

Particle E: Alumina particles manufactured by powder granulation method (GB, manufactured by Mizusawa Chemical Industry Co., Ltd.) Here, the powder granulation method involves drying and pulverizing a hydrogel, followed by extrusion or fluidization. It refers to a method of molding and flowing.

 [0033] [tar removal rate]

 Example 1-9, Comparative Example 1-6

 The tar removal rate at each gasification temperature when using the above particles A to E was determined. Table 1 shows the results.

 The tar removal rate was calculated using the following equation, where a is the amount of tar generated when sand (JIS No. 7) having no tar removal effect is used as particles, and b is the amount of tar when each particle is used. Removal rate = [1 (b / a)] X 100 (%)

 [0034] [Table 1]

 [Powder rate]

 Examples 10 and 11, Comparative Examples 7 and 8

As a particle, the particle ratio was determined when the particles A, B, D and E were used. Table 2 shows the results. In addition, the powdering rate was as follows. The force of the following formula was also calculated, where d is the weight and e is the weight of the particles initially charged.

 Powdering rate = {l- [d / e]} X 100 (%)

[Table 2]

Industrial applicability

 The method of the present invention is suitable for use in a field of energy and a field of research using a system for producing gas for fuel and gas for chemical raw materials.

Claims

The scope of the claims  [1] In a system in which a raw material is gasified, thermally decomposed, or partially oxidized in a fluidized bed furnace to obtain a generated gas, tar generated from the raw material is  Adsorbed and decomposed using fluid catalytic cracking catalyst, fluid catalytic cracking equilibrium catalyst, silica-alumina-based particles or alumina-based particles produced by oil immersion granulation, and Z or  Fluid catalytic cracking catalyst, fluid catalytic cracking equilibrium catalyst, silica-alumina-based particles or alumina-based particles produced by oil immersion granulation method and burn  For removing tar in a fluidized bed furnace.  [2] In a system in which a raw material is gasified, thermally decomposed, or partially oxidized in a fluidized bed furnace at a temperature of less than 900 ° C to obtain a product gas, the tar generated by the raw material power is  Adsorb and decompose using adsorbent particles, and Z or  Burn by attaching to adsorbent particles  For removing tar in a fluidized bed furnace. [3] The adsorptive particles are a fluid catalytic cracking catalyst, a fluid catalytic cracking equilibrium catalyst, silica / alumina particles, alumina particles, silica particles or clay mineral particles produced by an oil immersion granulation method. 3. The method for removing tar according to claim 2. [4] The alumina-based particle force is porous alumina, activated alumina, γ-alumina or activated bauxite,  The silica-based particles are silica gel,  4. The method for removing tar according to claim 3, wherein the clay mineral-based particles are activated clay, zeolite, and sepiolite.  5. The method for removing tar according to claim 2, wherein the adsorptive particles are ready-mixed concrete sludge and sludge cake thereof, lime cake, concrete or concrete structure, and waste of concrete structure.  6. The method for removing tar according to claim 15, wherein the adsorptive particles are charged into a fluidized bed furnace. [7] The method for removing tar according to any one of claims 115, wherein the adsorptive particles are used as a fluidizing medium for a publishing type fluidized bed or an internal circulation type fluidized bed. 16. The method for removing tar according to claim 15, wherein the adsorptive particles are used as a circulation medium of an external circulation type fluidized bed.  The method for removing tar according to any one of claims 11 to 15, wherein the adsorptive particles are scattered from a publishing type fluidized bed or an internal circulation type fluidized bed.