JPH0596735U - Unburned ash classification equipment - Google Patents

Abstract

(57) [Summary] [Purpose] Only the unburned combustible components are recirculated into the furnace, and the non-combustible components such as ash and sand are discharged to the outside of the combustion system.
Provide unburned ash classification equipment that can be economically processed. [Structure] A vibrating sieve-type classifier 10 is connected to the ash discharge section from the combustion boiler 1 that uses agricultural and forestry-based fuel, and only the unburned component that is classified as the sieve on the classifier 10 is discharged to the ejector 12. It is configured to be returned to the combustion chamber 2 of the combustion boiler 1 via the air transport pipe 13, and the ash and sand under the sieve in the classifying device 10 are sent out to the ash treatment equipment outside the boiler system by the ash discharge conveyor 6. This is the unburned ash classification equipment. [Effect] Boiler efficiency can be increased by collecting unburned combustible components and circulating combustion, the volume of waste treatment can be reduced, the capacity of ash treatment equipment and its driving force can be reduced, and air transportation can be performed. The equipment capacity and its driving force when it is carried out can be reduced, the abrasion in the transportation pipe is reduced, and the disposal cost can be reduced.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention is an unburned ash classifier that sorts unburned ash in the combustion ash discharged from a boiler that burns agricultural and forestry-based fuel using a classifier that uses a net, and returns it to the combustion chamber for reburning. Regarding equipment.

[0002]

[Prior Art]

 Generally, non-combustible foreign matter such as sand adheres to and mixes with agricultural and forestry fuels (hereinafter referred to as agricultural and forestry fuels) such as pin chips, bark, bagasse, rice husk, etc., in the generation place, storage state and handling process before being thrown into the boiler. .. In addition, the fixed carbon contained in such agricultural and forestry fuels requires a long time to completely burn. Therefore, generally, in an economically planned boiler, all of these cannot be completely combusted, and a part of them is collected as unburned components together with ash and incombustible foreign substances in the combustion gas treatment device. All such unburned components, ash and non-combustible foreign substances are discarded or circulated into the combustion chamber.

[0003]

[Problems to be solved by the device]

 However, the weight ratio of unburned matter in the collected ash to ash and non-combustible foreign matter, mainly sand, is about 1: 4. Then, the ratio becomes about 1: 1. Therefore, if all of the collected ash is discarded, not only the capacity of the ash processing facility will increase, but also the disposal cost will increase, and unburned combustible components will also be discarded, which is not economical.

Further, the method of circulating in the combustion chamber of the boiler is by air transportation, but not only the equipment capacity and equipment power are increased to transport the whole amount, but also the air transportation pipe is severely damaged due to sand, This cannot be avoided.

In order to solve such a problem, the present invention recycles only the combustible unburned component into the combustion chamber of the boiler and removes the unburned component such as ash and sand from the combustion system. It is to provide an unburned ash classification facility that can be discharged and economically treated.

[0006]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention has a vibrating screen type classifier connected to the ash discharge section of a combustion boiler that uses fuel from agricultural and forestry products. An unburned ash that has a circulation path that returns only the unburned components to be classified to the combustion chamber of the boiler, and is configured to send out the ash and sand under the sieve in the classification device to the ash treatment facility outside the boiler system. It is a classification facility.

[0007]

[Action]

 The present invention having such a structure focuses on the particle size distribution of combustible unburned matter and ash and sand, and by using a vibrating screen type classifier, ash and sand with a smaller particle size than unburned matter can be obtained. By classifying, the ash and sand under the sieve are sent to the ash treatment facility, and the remaining unburned components are returned to the combustion section and burned again, thereby saving fuel consumption and reducing the amount of waste treatment. ..

[0008]

【Example】

 An embodiment of the unburned ash classification facility of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view of an example of an agricultural and forestry fuel (wood scrap pinch) combustion boiler equipped with the unburned ash classification facility of the present invention. FIG. 2 is a schematic diagram showing the configuration of the unburned ash classification facility of the present invention.

The ash contained in the combustion gas in the wood chip pin-chip combustion boiler 1 shown in FIG. 1 is collected by the ash discharge chute 3 under the drum, the ash discharge chute 4 ′ under the multi-cyclone 4, and the electrostatic precipitator 5. Are discharged. Analysis of these ash emissions revealed that the ash discharged from the ash discharge chute 3 under the drum and the ash discharge chute 4'under the multi-cyclone 4 was 500 μm or more by weight, and about 15.7% by weight, The volume ratio is approximately 5 1.9% (bulk specific gravity 0.06), and the total calorific value is 5240 Kcal / Kg, which means that it can be combusted sufficiently as an unburned component. On the other hand, those with a particle size of 500 μm or less have a total calorific value of 480 Kcal / Kg. Moreover, the total calorific value of the ash discharged from the electrostatic precipitator 5 is 420 Kcal / Kg, and contains almost no unburned components.

Therefore, in the present invention, the under-drum ash discharge chute 3 of the combustion boiler 1 and the ash discharge chute 4'of the multi-cyclone 4 are connected to the upstream side of the vibrating one-stage sieve classifying device 10 (vibrating screen). Are arranged in this manner. The classifier 10 has a mesh opening of 500 μm, and the mesh on the sieve, that is, the uncombusted portion having a large particle size (hereinafter referred to as “mesh”) is connected to the air transport pipe 13 via the ejector 12. It is connected and pneumatically transported to the boiler combustion chamber 2. Further, those having a small particle size (ash and sand), which are under the sieve (under the mesh, hereinafter referred to as mesh), are connected to the ash discharge conveyor 6 and sent out of the boiler system.

Explaining in more detail the classification and recovery of the unburned components with reference to FIG. 2, the ash discharged from the drum lower ash discharge chute 3 and the multi-cyclone 4 lower ash discharge chute 4 ′ of the combustion boiler 1 are each ash. It is adapted to be introduced into the screen conveyer 11 via a sealing device 8 (for example, double or triple gate type or slide type damper or rotary valve) provided under the discharge chutes 3 and 4 '. Even if ash is intermittently discharged by the sealing device 8, the screw conveyor 11 continuously puts it into the vibrating screen 10, which is a classifying device, to remove unburned components remaining on the net and ash and sand falling under the net. Be classified.

At the downstream side of the vibrating screen 10, the suction of the ejector 12 installed on the air transport pipe 13 is carried out so that the unburned component remaining on the mesh is returned to the boiler combustion chamber 2 and re-combusted. Connected to outlet 12 '. The ash and sand that fall under the net are connected to the ash treatment equipment (ash bunker 7 etc.) by the ash discharge conveyor 6 as described above. Note that the unburned exhaust system on the upper side of the net is connected to the suction port 12 'of the ejector 12 as described above, and negative pressure acts on it, so that no ash or the like is blown out. Reference numeral 15 in the figure is a fan for transporting the air that has not been burned.

The mesh opening of the vibrating screen 10 as the classifying device in the present invention can be selected in the range of 500 to 2000 μm depending on the fuel to be handled.

[0014]

[Effect of the device]

 According to the present invention, by recovering and circulating the unburned combustible component using the classifying device as described above, the volume of the waste treatment component can be reduced, and the capacity of the ash treatment facility and its drive can be reduced. The power can be reduced, the equipment capacity for pneumatic transportation and its driving force can be reduced, the wear in the transportation piping is reduced, and the disposal cost can be reduced. Moreover, since the unburned component is returned to the combustion chamber and burned, the efficiency of the boiler is also improved.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an example of an agricultural and forestry-based fuel (wood chip pin tip) combustion boiler equipped with the unburned ash classification facility of the present invention.

FIG. 2 is a schematic diagram showing the configuration of an unburned ash classification facility of the present invention.

[Explanation of symbols]

 1 Combustion Boiler 2 Combustion Chamber 3 Drum lower ash discharge chute 4 Multi cyclone 4'Multi cyclone lower ash discharge chute 5 Electrostatic precipitator 6 Ash discharge conveyor 10 Classification device (vibrating screen) 11 Screw conveyor 12 Ejector 12 'Ejector suction Mouth 13 Air transport pipe

Claims (1)

[Scope of utility model registration request] 1. A vibrating screen type classifier is connected to an ash discharge section from a combustion boiler using an agricultural and forestry system fuel, and only the unburned part classified as a sieve on the classifier is used as a combustion chamber of the boiler. An unburned ash classification facility, which has a circulation system returning to the above, and is configured to send out ash and sand under the sieve in the classifier to an ash treatment facility outside the boiler system.