JPWO2017014299A1 - Biomass power generation system using bamboo as the main fuel and method for burning bamboo in the biomass power generation system - Google Patents

Abstract

  A combustion furnace in which primary air for efficiently burning fuel on the grate (33) and secondary air for secondary combustion of unburned matter and unburned gas generated on the grate (33) (32) and a water pipe (39) for cooling the furnace wall of the combustion furnace (32) to lower the temperature, the biomass power generation system (1) includes a water pipe (39 ) Cools the furnace wall of the combustion furnace (32) with the cooling water flowing therethrough, and burns bamboo as fuel.

Description

  The present invention relates to a biomass power generation system that generates power by burning bamboo as a main fuel and a method for burning bamboo in the biomass power generation system.

  2. Description of the Related Art Biomass power generation systems using woody biomass such as wood and waste biomass such as municipal waste, waste material, and waste plastic as fuel are used (for example, see Patent Document 1).

  In addition, a recycling system that focuses on bamboo materials left in bamboo groves as woody biomass (see Patent Document 2), an effective utilization method of woody biomass with a certain ratio of adding bamboo crushed and processed (Patent Document 2) 3), bamboo, which is woody biomass, is crushed into chips with a bamboo crusher, and this chip-shaped bamboo, coal, limestone, water, etc. are mixed and stirred with a kneader to make a paste-like fuel. A woody biomass supply method to a fluidized bed boiler (see Patent Document 4) and the like, in which a pasty fuel is supplied to a pressurized fluidized bed boiler, have been proposed.

JP 2009-270739 A JP 2013-146666 A JP 2012-219130 A JP 2012-175214 A

  However, the system that burns bamboo as the main fuel is not actually used, and no proposal has been made to achieve this. That is, if the bamboo material is burned at a suitable temperature of about 780 to 800 ° C., for example, components such as potassium, sodium, and iron contained in the bamboo material are fused as slag to the furnace wall. In fact, there is no means to solve this problem. On the other hand, bamboo forest that has been neglected in Japan is said to be 160,000 ha, and because it is imported cheaply from abroad as food, it is effectively used in biomass power generation systems using bamboo as the main fuel. If possible, it can be a promising solution to energy problems.

  An object of the present invention is to provide a biomass power generation system that can effectively use bamboo as a main fuel, and a method for burning bamboo in the biomass power generation system.

In order to solve this problem, the present invention provides:
A combustion furnace into which primary air for efficiently burning fuel on the grate, and unburned matter generated on the grate, and secondary air for secondary combustion of unburned gas;
A water pipe for cooling the furnace wall of the combustion furnace to lower the temperature;
In a biomass power generation system equipped with
Reducing the flow rate of the primary air,
Cooling the furnace wall of the combustion furnace with cooling water flowing through the water pipe,
Bamboo material as the fuel is burned.

  According to this biomass power generation system, slag adhesion to the furnace wall when bamboo is burned can be suppressed. Therefore, bamboo can be used as the main fuel.

The present invention also provides:
A combustion furnace into which primary air for efficiently burning fuel on the grate, and unburned matter generated on the grate, and secondary air for secondary combustion of unburned gas;
A water pipe for cooling the furnace wall of the combustion furnace to lower the temperature;
A combustion method in a biomass power generation system comprising:
Using bamboo as the fuel,
Reducing the flow rate of the primary air,
Cooling the furnace wall of the combustion furnace with cooling water flowing through the water pipe,
The bamboo material is burned.

  According to this combustion method, slag adhesion to the furnace wall when bamboo is burned can be suppressed. Therefore, bamboo can be used as the main fuel.

  According to the present invention, bamboo can be effectively used as a main fuel.

It is the schematic which shows the structure of a biomass power generation system clearly. It is a figure which shows the structural example of the whole biomass power generation system. It is a figure which shows the connection of each structure in a biomass power generation system, and flows, such as fuel and water. It is the figure seen from the back side of the system shown in FIG. 1 etc. which shows the structural example of a fuel supply apparatus (multi-screw feeder). It is the figure seen from the back side of the system shown in FIG. 1 etc. which shows the structural example of a grate.

  Hereinafter, a preferred embodiment of a seat suspension structure according to the present invention will be described in detail with reference to the drawings (see FIGS. 1 to 5).

  1 to 5 show an embodiment of the present invention. FIG. 1 is a schematic diagram showing the configuration of the biomass power generation system in an easy-to-understand manner, FIG. 2 is a diagram showing an example of the overall configuration of the biomass power generation system, and FIG. FIG. 4 is a diagram showing a configuration example of a fuel supply device (multi-screw feeder), and FIG. 5 is a perspective view showing a configuration example of a grate.

  Biomass power generation system 1 performs pyrolysis and carbonization as needed in a state where waste biomass such as woody biomass and municipal waste is included in the fuel, burns it in a combustor, and uses the generated gas as energy It is a system that generates electricity by operating. The biomass power generation system 1 of the present embodiment can be divided into the following eight units if functionally classified.

<First unit 10>
A unit that transports and prepares fuel. The first unit 10 includes an unloading place 11 and a temporary fuel storage place 13 (see FIG. 1).

  The unloading place 11 is a place where the biomass fuel transported by the tractor TR or the like is unloaded (see FIG. 1). The unloaded biomass fuel is shredded by a shredder device when necessary and stored in a temporary storage place 13. In the case of the biomass power generation system 1 of the present embodiment that mainly uses bamboo as biomass, raw materials of bamboo such as crushed bamboo chips are stored. Finally, the fuel is moved to the fuel storage 21, and other stones, sand, mud, etc. are used for road pavement materials, for example.

<Second unit 20>
The unit where combustion is stored. The second unit 20 includes a fuel storage 21 having a moving floor and a conveyor 23 to the fuel supply system.

  The fuel storage 21 stores biomass fuel. The fuel storage 21 has a capacity capable of holding fuel for a required operation time so that fuel does not need to be replenished on the way. The stored biomass fuel is automatically carried out by the hydraulically controlled floor and chain conveyor controlled by the fuel supply system, and conveyed to the third unit 30 by the conveyor 23.

<Third unit 30>
The third unit 30 is a boiler system. The third unit 30 includes fuel supply devices 31A and 31B, a combustion furnace 32, a boiler 34, an internal pipe 35, a boiler cleaning device (not shown), an economizer 37, a super heater 38, and a water pipe 39.

  The fuel supply devices 31 </ b> A and 31 </ b> B are devices that supply fuel to the combustion furnace 32. In this embodiment, the fuel conveyed by the conveyor 23 is supplied to the combustion furnace 32 using a spiral multi-screw feeder (see FIGS. 1 and 4). Although not specifically shown, in order to prevent backfire, the supply system has a fire extinguishing unit designed with redundancy.

  The combustion furnace 32 is a furnace for burning supplied biomass fuel, and is designed as a stoker-type combustion furnace in which appropriate air is supplied to the furnace of the inclined grate 33. The structure of the combustion furnace 32 is impermeable to gas and can support the weight of the inner wall and equipment of the furnace. Depending on the size, several inspection and maintenance doors are provided. Although not shown in particular, the combustion furnace 32 is lined with a multilayer inner wall. For example, a high alumina castable (refractory material) or a refractory brick is used as a front layer in a high load place. Low-cement materials are used in low-load areas. The middle layer uses common refractory bricks and castables, and the outer layer uses thermal insulation. Depending on the size, the combustion furnace 32 is often lined at the factory.

  Further, in the combustion furnace 32, by recirculating the exhaust gas, not only wet fuel can be used, but also combustion temperature control for minimizing NOx emission can be performed. Combustion is always controlled in consideration of the state of load and pressure, and the ratio of excess air (λ control).

  The grate 33 is self-supporting and is placed in the combustion furnace 32, and its dimensions are determined at the design stage (see FIG. 5). Several hydraulic cylinders move the rods of the grate 33 back and forth to completely burn the fuel. Incombustibles (ash and other things) move on the grate 33 and are discharged from the end of the combustion furnace 32 by the discharge conveyor (externally through the discharge hole).

  In the biomass power generation system 1 of the present embodiment, primary air and secondary air are supplied to the fuel placed on the grate 33 and burned (see FIG. 2). That is, in order to efficiently burn the fuel on the grate 33, primary air is blown from below the grate 33, and secondary air is used to cause secondary combustion of unburned gas and unburned matter generated on the grate 33. In order to prevent clinker from adhering to the wall surface.

  More specific description will be given with reference to FIG. In the stoker-type combustion furnace 32, primary air A is supplied from the bottom of the grate 33 to the primary combustion chamber above the grate 33 to cause primary combustion of the fuel on the grate 33, and the secondary above the primary combustion chamber. The secondary air B is supplied to the combustion chamber, the unburned gas and unburned matter generated in the primary combustion chamber are secondarily burned, and the combustion gas is discharged from the upper part of the post combustion grate 33 (the exhaust gas after passing through the dust collector). ) Partially withdrawn and blown it into the secondary combustion chamber to form a reduction zone to reduce NOx, and then reduce CO and dioxins at a high temperature by secondary combustion and at the same time realize low air ratio combustion To do. The primary air A is air (normal air) supplied from the boiler 34, and the primary air A 'is recirculated air. The primary air A 'is used for fuel reduction and drying.

  The boiler 34 is disposed in the middle of the internal pipe 35, and heats the circulating water by exchanging heat between the combustion exhaust gas and the circulating water. A boiler cleaning device (not shown) cleans the used boiler 34. The third unit 30 further includes a soot blower (soot) using steam for online cleaning of the super heater 38 and the economizer 37.

  The economizer 37 is one of the feed water heaters of the boiler 34, and heats the feed water using the residual heat of the exhaust. The economizer 37 is configured by a water pipe or the like provided in the flue 36.

  In the biomass power generation system 1, most of the ash in the combustion gas is removed at the portion of the enclosure C shown in a cloud shape in FIG. 2. This is because a large amount of ash is collected through the duct of the downdraft (see FIG. 2). Further, in the subsequent upward air flow to the super heater 38, only very small fine powder remains, so that the amount of clinker adhering to the pipe of the super heater 38 can be reduced.

  The water pipe 39 is a pipe for flowing cooling water to cool the furnace wall of the combustion furnace 32, and is arranged around the flue 36. Although the specific configuration of the water pipe 39 is not particularly limited, the water pipe 39 in the biomass power generation system 1 of the present embodiment is mostly a horizontal water pipe 39a arranged horizontally, a vertical water pipe 39b connecting these horizontal water pipes 39a, and It includes a fine water pipe 39c that stops halfway (see FIG. 2 and the like).

<Fourth unit 40>
The 4th unit 40 is a unit which processes combustion gas. The fourth unit 40 includes a primary dust collector 41, an electrostatic dust collector 42, a ventilation fan 43, and a chimney 45.

  The primary dust collector 41 that removes coarse particles is connected to the flue 36 after passing through the economizer 37. Next, the coarsely collected exhaust gas is further collected by the electrostatic dust collector 42. The separated dust is continuously removed, and the cleaned exhaust gas is guided to the steel chimney 45 through the ventilation fan 43. The chimney 45 is self-supporting, and the height is designed in accordance with the height required by the municipality of the installation location.

<Fifth unit 50>
The 5th unit 50 is a unit which constitutes a power generator. The fifth unit 50 includes a condensing turbine 51, a steam condenser 52 and a condensate tank 53, an air cooler 54, and an external pipe 55 that are gear-connected to the generator 56.

  In the fifth unit 50, the condensing turbine 51 is rotated by superheated steam produced by the boiler 34. If steam is extracted from the condensing turbine 51, it can be used for various purposes (for example, processing, heating). The condensed steam after use is collected in the non-pressure condensate tank 53 and then returned to the BFW (boiler supply water) tank 63. The vapor condenser 52 is connected to the condensation tank.

<Sixth unit 60>
The sixth unit 60 is a unit that performs water treatment. The sixth unit 60 includes a fresh water treatment device 61, a deaeration device 62, a BFW (boiler supply water) tank 63, an instrumented BFW pump 64, and a drain pipe system 65.

  A chemical water treatment system is composed of a cation (cation) exchanger and a reverse osmosis system. The BFW tank 63 is composed of a thermal degassing device and instrumentation therein.

<Seventh unit 70>
The seventh unit 70 is a unit that performs ash treatment. The seventh unit 70 includes an ash extraction device 71 from the grate 33, an ash extraction from the middle of the flue 36, an ash extraction device 73 from the primary dust collector 41 and the electrostatic dust collector 42.

  The ash of the grate 33 in the combustion furnace 32 is taken out from the lower part at the end of the combustion furnace 32. Ashes from the middle of the flue 36 are carried to a common ash removal position. The ash of the primary dust collector 41 and the electrostatic dust collector 42 is directly taken out from a take-out port (hopper) of a case (not shown). The boundary of the ash treatment system becomes the take-off nozzle of the corresponding rotary valve. Each ash is collected separately from each outlet and delivered to an industrial waste disposal contractor.

<Eighth unit 80>
The eighth unit 80 is a unit constituting the control device. The eighth unit 80 includes a control panel 81, an I & P field device (hereinafter, not shown), a combustion control device, and a boiler control device (see FIG. 3).

  Subsequently, in the biomass power generation system 1 described above, how to burn when bamboo is used as the main fuel will be described (see FIG. 3 and the like).

  When the bamboo material is burned as the main fuel, combustion is performed while reducing the flow rate of the primary air and cooling the furnace wall of the combustion furnace 32 with the cooling water flowing through the water pipe 39. Thereby, the slag adhesion to the furnace wall at the time of burning bamboo can be suppressed.

  The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the scope of the present invention.

  INDUSTRIAL APPLICABILITY The present invention is suitable for application in the case of generating power by burning bamboo as a main fuel in a biomass power generation system.

DESCRIPTION OF SYMBOLS 1 ... Biomass power generation system 10 ... 1st unit 11 ... Unloading place 13 ... Temporary storage place 20 ... 2nd unit 21 ... Fuel storage 23 ... Conveyor 30 ... 3rd unit 31A ... Fuel supply apparatus 31B ... Fuel supply apparatus 32 ... Combustion Furnace 33 ... Grate 34 ... Boiler 35 ... Internal piping 36 ... Flue 37 ... Economizer 38 ... Super heater 39 ... Water pipe 39a ... Cross water pipe 39b ... Vertical water pipe 39c ... Fine water pipe 40 ... Fourth unit 41 ... Primary dust collector 42 ... Electrostatic dust collector 43 ... Ventilation fan 45 ... Chimney 50 ... Fifth unit 51 ... Condensing turbine 52 ... Steam condenser 53 ... Condensate tank 54 ... Air cooler 55 ... External piping 56 ... Generator 60 ... Sixth unit 61 ... Fresh water Processor 62 ... Deaerator 63 ... BFW (boiler supply water) tank 64 ... BFW pump 65 with instrumentation ... Drainage pipe system 70 ... 7 unit 71 ... ash extraction device 80 ... eighth unit from the ash removal device 73 ... primary dust collector 41 and the electrostatic precipitator 42 from the grate 33 81 ... control panel

Claims (2)

A combustion furnace into which primary air for efficiently burning fuel on the grate, and unburned matter generated on the grate, and secondary air for secondary combustion of unburned gas;
A water pipe for cooling the furnace wall of the combustion furnace to lower the temperature;
In a biomass power generation system equipped with
Reducing the flow rate of the primary air,
Cooling the furnace wall of the combustion furnace with cooling water flowing through the water pipe,
A biomass power generation system using bamboo as a fuel, characterized by burning bamboo as the fuel. A combustion furnace into which primary air for efficiently burning fuel on the grate, and unburned matter generated on the grate, and secondary air for secondary combustion of unburned gas;
A water pipe for cooling the furnace wall of the combustion furnace to lower the temperature;
A combustion method in a biomass power generation system comprising:
Using bamboo as the fuel,
Reducing the flow rate of the primary air,
Cooling the furnace wall of the combustion furnace with cooling water flowing through the water pipe,
A method for burning bamboo material in a biomass power generation system, characterized by burning the bamboo material.

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