WO2010005145A1

WO2010005145A1 - Gas generating system

Info

Publication number: WO2010005145A1
Application number: PCT/KR2008/005163
Authority: WO
Inventors: Yang Ho Jung
Original assignee: ZHUAI DEVELOPMENT Co Ltd
Current assignee: ZHUAI DEVELOPMENT Co Ltd
Priority date: 2008-07-11
Filing date: 2008-09-03
Publication date: 2010-01-14
Anticipated expiration: 2011-01-11
Also published as: KR100883952B1

Abstract

Disclosed herein is a gas generating system for producing combustible gas from biomass materials such as waste wood chips. The gas generating system includes a combustion chamber defined by a refractory layer; means for supplying the biomass material to the combustion chamber; means for distributing the biomass material supplied from the means for supplying biomass material; a gas-discharging port formed in the combustion chamber; an ash reception chamber disposed in the combustion chamber; a biomass material grate having a hole and disposed between the combustion chamber and the ash reception chamber to allow ash generated in the combustion chamber to pass to the ash reception chamber; means for discharging the ash accumulating in the ash reception chamber; and means for supplying oxygen into the combustion chamber through the ash reception chamber.

Description

GAS GENERATING SYSTEM

Technical Field

[1] The present invention relates to a gas generating system for producing combustible gas from wood-based waste materials such as waste wood chips, sawdust, stems or straws of crops, grain hulls and fallen leaves, i.e. biomass material, and it relates more particularly to a gas generating system for producing bioenergy from biomass material in a continuous and automatic manner.

[2]

Background Art

[3] Wood furniture, construction wood, sawdust, agricultural crops and the like are extensively used in daily life and in a variety of industrial fields, but after being used or cultivated only a small part of them are recycled, and the larger portion thereof is classified as waste material and is used as landfill material or incinerated. In 2005, the amount of waste materials including by-products generated in the timber industry was 55,110,000 tons, only 1,830,000 tons, i.e., 3.3% of the amount of industrial waste was actually recovered or recycled.

[4] When waste wood, which is not recycled, is required to be buried, there is a need for a landfill site. Alternatively, when waste wood is required to be incinerated, it is difficult to advantageously achieve considering the recent increase in oil prices.

[5] Likewise, in products, such as tires, vinyl and plastic articles made of synthetic resin, only a small portion of the amount of used products is recycled, and the larger portion thereof is classified as waste material and buried or incinerated. In order to overcome the above problems, various technologies are being developed, which are designed to contribute to the energy saving in such a manner that synthetic resin waste is burned as fuel in a combustion chamber and the high temperature heat of combustion is recovered as energy.

[6] One of the technologies designed to incinerate synthetic resin is disclosed in Korean

Patent Registration No. 10-0656093.

[7] As shown in FIG. 6, the technology disclosed in Korean Patent Registration No.

10-0656093 comprises a first combustion chamber 100 having an internal wall composed of refractory material 102, a combustion unit 110 disposed at the lower end of the first combustion chamber 100, in which a plurality of semi-cylindrical injection nozzles 112 each having injection holes 113 formed in a predetermined direction is mounted on a conical rotating plate 111, a plurality of retainers 114 are attached to the circumference of the lower end of the rotating plate 111, and a hollow shaft 116 is fixed to the center of the lower end of the rotating plate 111 for the supply of combustion air, a preheating burner 120 mounted on the wall of the first combustion chamber 110 over the rotating plate 111, first oxygen supply pipes 130 provided over the preheating burner 120 and having a plurality of nozzles 131 inclined at a predetermined angle with respect to the axis of the first combustion chamber 110, a fuel supply unit 140 provided over the first oxygen supply pipe 130 to supply the first combustion chamber 110 with combustible waste materials as fuel, and a second oxygen supply pipe 150 vertically disposed at the axis of the first combustion chamber 100 over the fuel supply unit 140, and a discharge port 160 formed in the wall of the first combustion chamber 100 over the second oxygen supply pipe 150.

[8] The technology disclosed in the registration is intended to recover heat generated from incineration of synthetic resin, and is entirely different from the present invention which produces combustible gas from biomass material.

[9] Apparatuses, which have been developed until now to generate combustible gas from a relatively large amount of biomass material, may be classified into an upper discharge type in which gas is discharged at an upper level of a system and a lower discharge type in which gas is discharged at a lower level of a system.

[10] In the upper discharge type system, it is difficult to supply biomass material to the system, thus making continuous operation impossible.

[11] In the lower discharge type system, although the continuous generation of gas is achievable, the temperature of gas is very high because the gas is directly discharged from a high temperature zone. More specifically, the lower discharge type system has various disadvantages in that the temperature of gas is generally 500 ⁰C or higher, a large amount of dust and CO₂ is generated, the caloric content of the gas is mostly 1,500 kcal/m³ or less, and the removal of combustion ash is difficult.

[12]

Disclosure of Invention Technical Problem

[13] Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a gas generating system for producing combustible gas, i.e. bioenergy, in a continuous and automatic manner.

[14] Another object of the present invention is to provide a gas generating system for producing gas having improved caloric content.

[15] A further object of the present invention is to provide a gas generating system for producing gas produced by thorough and even agitation and burning using a screw mounted on the upper end of a distillation layer. [16] Yet another object of the present invention is to provide a gas generating system which is capable of modifying the constituents of gas. [17]

Technical Solution

[18] In order to accomplish the above object, the present invention provides a gas generating system for producing combustible gas from biomass material, the biomass material being crushed to a predetermined size, the system including: a combustion chamber including an inner wall composed of a refractory layer; means for supplying the biomass material to an upper portion of the combustion chamber; means for evenly distributing the biomass material supplied by the means for supplying biomass material; a gas-discharging port formed in an upper portion of the combustion chamber to discharge gas generated in the combustion chamber; an ash reception chamber disposed at a lower portion of the combustion chamber; a biomass grate disposed between the combustion chamber and the ash reception chamber to allow ash generated in the combustion chamber to pass to the ash reception chamber as needed, the biomass material accumulating on a biomass grate having a hole to supply oxygen into the combustion chamber; means for discharging the ash accumulating in the ash reception chamber; and means for supplying oxygen into the combustion chamber through the ash reception chamber.

[19] The means for evenly distributing the biomass material may include two rotating screws disposed at upper and center positions in the combustion chamber, respectively.

[20] The two rotating screws may be rotated at a rotating speed of 2 to 3 rpm.

[21] The means for supplying the biomass material may include a hopper for receiving the biomass material and a rotary valve for controlling an amount of the biomass material supplied from the hopper into the combustion chamber.

[22] The biomass grate may include a plurality of pieces each having a T-shaped cross section, in which each of the plurality of T-shaped pieces has an upper surface facing the combustion chamber and carrying the biomass material thereon, each of the plurality of T-shaped pieces is provided at a cross point with a rotating pin, and thus the upper surface of each of the T-shaped pieces is inclined by a driving force applied to a lower portion thereof.

[23] The means for discharging the ash may include a conveyor belt disposed at a lower position of the ash reception chamber.

[24] The means for supplying oxygen may control an amount of oxygen supplied from the combustion chamber.

[25]

Advantageous Effects [26] In the above-described gas generating system according to the present invention, combustible gas, i.e. bioenergy, can be produced in a continuous and automatic manner.

[27] According to the gas generating system, the caloric content of the produced gas can be enhanced by about 20 35%.

[28] Furthermore, according to the gas generating system, gas which is obtained by even reaction can be produced.

[29] In addition, according to the gas generating system, the constituents of gas can be modified as needed.

[30]

Brief Description of the Drawings

[31] The above and other objects, features and further advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[32] FIG. 1 is a cross-sectional view of a gas generating system according to an embodiment of the present invention;

[33] FIG. 2 is a plan view of a biomass grate according to an embodiment of the present invention;

[34] FIG. 3 to 5 is a cross-sectional view of the biomass grate according to an embodiment of the present invention; and

[35] FIG. 6 is a cross-sectional view of a conventional combustion apparatus.

[36]

Best Mode for Carrying Out the Invention

[37] Hereinafter, a gas generating system according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[38] FIG. 1 is a cross-sectional view of a gas generating system according to an embodiment of the present invention.

[39] Referring to FIG. 1, an upper cylindrical refractory layer 13 is composed of refractory cement and expanded perlite in a mixing ratio of 1 : 5 by volume.

[40] A lower refractory layer 12, which is an oxide layer made of refractory blocks, is disposed under the upper refractory layer 13. The external surfaces of the upper and lower refractory layers 13, 12 are surrounded by a steel plate 11 having a thickness ranging from 6 mm to 8 mm.

[41] A lid part 15, which is covered at an external surface with a steel plate, is disposed on the upper end of the upper refractory layer 13.

[42] The lid part 15 is provided with a hopper 23 for supplying biomass material which is crushed by an additional apparatus, and a rotary valve 25 for controlling the supply of only a required amount of biomass material from the hopper 23 to a combustion chamber 8.

[43] The lid part 15 is further provided with an inspection window which allows an observer to observe therethrough the combustion conditions of gas in the combustion chamber 8. In addition, a decelerating motor 37 is mounted on the lid part 15 in such a manner that a rotating shaft 35 of the decelerating motor 37 is oriented to be perpendicular to screws 31, 33 in the combustion chamber 8 and coupled thereto. The decelerating motor 37 is operated so as to rotate the screws 31, 33 in a rotational speed of 1 to 5 rpm, and preferably 2 to 3 rpm.

[44] Gas-discharging ports 10, 17 are formed in the region of the upper refractory layer 13 adjacent to the lid part 15. Each of the gas-discharging ports 10, 17 communicates with an exhaust flue 55 for discharging smoke generated during the initial combustion of biomass material, and also communicates with a transport pipe 51 for transporting gas normally generated in the combustion chamber 8. Of course, the gas transport pipe 51 and the exhaust flue 55 are provided with an electromagnetic valve 52 and 56, respectively. Although the representation of the exhaust flue 10 and the gas transport pipe 51 communicating with the gas-discharging port 10 is omitted in FIG. 1, the exhaust flue 10 and the gas transport pipe 51 are actually connected to the gas- discharging port 10. The gas -discharging port 10 may be connected in parallel to the gas-discharging port 17.

[45] The gas generating system according to this embodiment of the present invention is configured such that a ratio of diameter to height falls within a range of 1 : 1.5 2.5. The gas generating system includes an ash collecting chamber 39, in which the lower part of the ash collecting chamber 39 is made of thermal insulating refractory concrete composed of refractory cement and expanded perlite.

[46] When biomass material in the combustion chamber 8 starts to be burned, what is generated is not normal gas but smoke. In order to discharge the smoke through the exhaust flue 55, the electromagnetic valve 56 mounted on the exhaust flue 55 is opened whereas the electromagnetic valve 52 mounted on the gas transport pipe 51 is closed, thus allowing the discharge of the smoke through the exhaust flue 55. When the biomass material in the combustion chamber 8 is burned normally and thus normal gas is generated, the electromagnetic valve 56 mounted on the exhaust flue 55 is closed whereas the electromagnetic valve 52 mounted on the gas transport pipe 51 is opened, thus allowing the gas generated in the combustion chamber 8 to be supplied to a consuming region or a storage tank through the gas transport pipe 51.

[47] A lower section of the internal space defined by the upper refractory layer 13 constitutes the combustion chamber 8 in which the crushed biomass material is burned. The combustion chamber 8 is provided at the bottom thereof with a biomass grate 40. Therefore, biomass material, which is introduced into the combustion chamber 8 through action of the rotary valve 25 serving as the biomass supplying means, is evenly distributed by the screws 31, 33, and accumulates on the biomass grate 40.

[48] Positioned below the biomass grate 40 is an ash reception chamber 39 in which the incinerated ash is temporarily stored. The ash reception chamber 39 is provided at one lateral region thereof with an ash-discharging port 19 connected to means for disposing of ash, and is provided at another lateral region with an air intake port 14 which functions to supply oxygen required to burn the biomass material in the combustion chamber 8. In this embodiment, the gas generating system may be provided with means for controlling the supply of and supplying oxygen, which is configured to control the amount of air, i.e., oxygen supplied through the air intake port 14, and to supply the amount of oxygen required in the combustion chamber 8. The means for disposing of ash may include a conveyor belt 61 at the bottom of the ash reception chamber 39 so as to automatically dispose of ash depending on the amount of ash accumulation in the ash reception chamber 39.

[49] Biomass material is burned in the combustion chamber 8 under a predetermined temperature condition to thus generate CO and CO₂ as well as heat. CO₂ is immediately reduced to CO, that is, combustible gas due to the combustion heat. At this point, the biomass material is thermally decomposed into combustible gases, such as, H₂, CH₄, C₂ H₆, C₃H₈, C₄H₁₀, , C_nH_2n+2 (n: natural number). By controlling the amount of oxygen supplied through the air intake port 14, desired gases may be produced.

[50] Structure of the biomass grate 40 is now described.

[51] FIG. 2 is a plan view of the biomass grate 40 according to an embodiment of the present, and FIG. 3 to 5 is a cross-sectional view of the biomass grate 40.

[52] Referring to FIG. 2, the biomass grate 40 includes a circular frame 41 to support individual components of the biomass grate 40, in which all of the biomass grate 40, the circular frame 41 and the associated components are made of a steel material. The frame 41 is fixed to the lower refractory layer 12, as shown in FIG. 1.

[53] Referring to FIGS. 2 to 5, the biomass grate 40 further includes support plates 41 each having a T-shaped cross section so as to open or close the area defined by the circular frame 41. Each of the support plates 41 is provided at the upper surface thereof with a plurality of air holes 44 at intervals of 80 100mm, each having a diameter ranging from 10 to 12mm. As shown in FIG. 5, each of the T-shaped support plates 41 is rotatably supported at the opposite ends thereof to the circular frame 41 via rotating pins 45, and is rotatably supported at a lower end thereof to movable bars 46 via a rotating pin 47_Λ

[54] FIG. 3 shows the T-shaped support plates 43 which are in the closed position, and FIG. 4 shows the T-shaped support plates 43 which are in the opened position.

[55] When the movable bars 46 are moved in the direction of the arrows in FIG. 3, the T- shaped support plates 43 are rotated to the opened position, as shown in FIG. 4. When the movable bars 46 are moved in the direction opposite to the direction of the arrows in FIG. 3, the T-shaped support plates 43 are rotated to the closed position, as shown in FIG. 3A.

[56] By the operation of the biomass grate 40, ash generated in the combustion chamber 8 is discharged into the ash reception chamber 39.

[57] Hereinafter, operation of the gas generating system according to an embodiment of the present invention will be described.

[58] Biomass material, which is prepared from waste materials such as wood chips and sawdust of wood furniture or construction wood, sawdust, stems of agricultural crops, grain hulls and fallen leaves, is crushed into a size of 60mm or less and is loaded in the hopper 23. Then, a predetermined amount of biomass material is introduced into the combustion chamber 8 by opening the rotary valve 25. Thereafter, the crushed biomass material is distributed by the rotation of the screws 31, 33 disposed in the upper section of the combustion chamber 8, and then accumulates on the biomass grate 40 installed at a low level in the combustion chamber 8. Because the biomass material has an uneven distribution of constituents such as moisture and the biomass material itself, a desired amount of combustible gas can be produced by efficiently agitating the biomass material using the screw 31 and supplying the biomass material to the combustion chamber 8.

[59] When a desired amount of biomass material accumulates in the combustion chamber

8, an ignitor (not shown) is put into the ash reception chamber 39 through the ash- discharging port 19, and then the biomass material accumulating on the biomass grate 40 is ignited by the ignitor through the air holes 44 of the T-shaped support plates 43 or gaps between the slightly opened T-shaped support plates 43, followed by closing of the ash-discharging port 19.

[60] After the ignition of the biomass material, smoke is generated until the temperature of the biomass material in the combustion chamber 8 rises to the normal temperature at which normal gas is generated. At this time, when the electromagnetic valve 56 mounted on the exhaust flue 55 is opened, the smoke is discharged outside through the gas-discharging ports 10, 17 and the exhaust flue 55.

[61] Thereafter, when a temperature of the biomass material in the combustion chamber 8 rises to the normal gas -generating temperature, the electromagnetic valve 56 mounted on the exhaust flue 55 is closed while the electromagnetic valve 52 mounted on the gas transport pipe 51 is opened. Subsequently, an amount of oxygen supplied from the oxygen-supplying means provided at the air intake port 14 is controlled to generate desired gases, such as, H₂, CH₄, C₂H₆, C₃H₈, and C₄H₁₀.

[62] The gas generated in this stage is supplied to a consuming region or a storage tank through the gas-discharging ports 10, 17. At this point, the temperature of the gas discharged through the gas-discharging ports 10, 17 may be in a range from 50 to 25O⁰C depending on the kinds of gas generated, the kind of supplied biomass material and other conditions. In an embodiment, the temperature of the gas is 200⁰C or lower, an pressure in the combustion chamber 8 is 0.65MPa or lower, and caloric content of the generated gas is in a range from 1,800 to 2,000kcal/m³.

[63] If an abnormal situation occurs in the combustion chamber 8, the electromagnetic valve 56 mounted on the exhaust flue 55 is automatically opened while the electromagnetic valve 52 mounted on the gas transport pipe 51 is automatically closed, thus allowing the gas generated in the combustion chamber 8 to be discharged through the exhaust flue 55.

[64] The ash generated by the combustion of the biomass material is introduced into the ash reception chamber 39 through gaps between the opened T-shaped support plates 43 of the biomass grate 40, and the ash introduced into the ash reception chamber 39 is discharged through the ash-discharging port 19. Even if the ash-discharging port 19 is opened during the discharge of ash, there is no major problem. After the discharge of ash, the ash-discharge port 19 is preferably closed to promote the generation of high quality gas.

[65] In the case in which the conveyor belt 61 is provided at the bottom of the ash reception chamber 39, the automatic discharge of ash becomes possible thanks to the conveyor belt 61. More specifically, the T-shaped support plates 43 of the biomass grate 40 are automatically opened to allow the ash to fall on the conveyor belt 61, depending on an amount of ash accumulating on the T-shaped support plates 43, and the ash on the conveyor belt 61 is discharged from the ash reception chamber 39.

[66] In this embodiment, although the descriptions and the illustrations relating to automated facilities required for the operation of the gas generating system according to the present invention are omitted, all of the processes of supply of biomass material, generation of gas, discharge of ash, and the processes for safe operation may be automatically controlled by incorporating an automated circuit using a computer or the like.

[67]

Industrial Applicability

[68] The gas generating system according to the present invention is capable of generating combustible gas from biomass material, thus enabling the recycling of waste biomass material. [69]

Claims

[1] A gas generating system for producing combustible gas from biomass material, the biomass material being crushed to have a predetermined size, comprising: a combustion chamber including an inner wall composed of a refractory layer; means for supplying the biomass material to an upper portion of the combustion chamber; means for evenly distributing the biomass material provided from the means for supplying biomass material; a gas-discharging port formed in an upper portion of the combustion chamber to discharge gas generated in the combustion chamber; an ash reception chamber disposed at a lower portion of the combustion chamber; a biomass grate disposed between the combustion chamber and the ash reception chamber to allow ash generated in the combustion chamber to pass to the ash reception chamber as needed, the biomass material accumulating on the biomass grate, the biomass grate having a hole to supply oxygen into the combustion chamber; means for discharging the ash accumulating in the ash reception chamber; and means for supplying oxygen into the combustion chamber through the ash reception chamber.

[2] The gas generating system according to claim 1, wherein the means for evenly distributing the biomass material comprises two rotating screws disposed at upper and center positions in the combustion chamber, respectively.

[3] The gas generating system according to claim 2, wherein the two rotating screws are rotated at a rotating speed of 2 to 3 rpm.

[4] The gas generating system according to claim 1, wherein the means for supplying the biomass material comprises a hopper for receiving the biomass material and a rotary valve for controlling an amount of the biomass material supplied from the hopper into the combustion chamber.

[5] The gas generating system according to claim 1, wherein the biomass grate comprises a plurality of pieces each having a T-shaped cross section, in which each of the plurality of T-shaped pieces has an upper surface facing the combustion chamber and carrying the biomass material thereon, each of the plurality of T-shaped pieces is provided at a cross point with a rotating pin, and thus the upper surface of each of the T-shaped pieces is inclined by a driving force applied to a lower portion thereof.

[6] The gas generating system according to claim 1, wherein the means for dis- charging the ash comprises a conveyor belt disposed at a lower position of the ash reception chamber. [7] The gas generating system according to claim 1, wherein the means for supplying oxygen controls an amount of oxygen supplied from the combustion chamber.