CN1258712A - Biomass gasifying and purifying circular fluid-bed system - Google Patents

Abstract

A biomass circulating fluidized bed gasification purification system, the invention adopts an air preheating circulating fluidized bed as a gas generation and air preheating system, and the gas purification system is composed of a cyclone separator, a venturi tube and a water washing tower, and also It has sewage treatment and circulation systems such as sewage treatment pools. This invention has unique design, wide applicability and high technical performance. It can treat several kinds of waste materials alone or simultaneously, including sawdust, rice husk, straw or bagasse, etc., daily The amount of waste to be processed can range from 10 tons to 200 tons, and the gas generated can generate electricity from hundreds of kW to several thousand kW, with low water consumption and high thermal efficiency (greater than 16%).

Description

Biomass circulating fluidized bed gasification purification system

The invention relates to the technology of gasifying biomass into combustible gas and purifying and utilizing it. Especially the technology of biomass gasification into combustible gas for power generation.

Biomass gasification and purification technology can convert biomass waste such as waste wood, chaff, orange stalks, etc. into clean combustible gas energy that can be used. Large-scale utilization is of great significance to environmental protection and sustainable development of society, so at present, biomass gasification purification technology has attracted more and more attention.

At present, domestic technologies for gasifying biomass into combustible gas for power generation are mainly based on fixed-bed gasifiers, which cannot process a variety of wastes at the same time. Only simple water washing method is used, which consumes a lot of water and has low thermal efficiency. However, foreign gasification power generation technologies are mainly large-scale, and the gasification furnace and gas purification system are too complicated to be popularized, especially in small and medium scale (below 5000kW).

The purpose of the present invention is to provide a biomass circulating fluidized bed gasification and purification system that provides gas source for small and medium-scale gas-fired power stations, so that the system is suitable for processing various biomass wastes, has high efficiency and meets environmental protection requirements.

The present invention has three main features: (1) adopts air preheating circulating fluidized bed gasification furnace; (2) consists of cyclone separator, Venturi tube and water washing tower to form a multi-stage gas purification system; (3) conforms to environmental protection The required sewage purification and circulation system.

Concrete technical scheme of the present invention is:

(1) A circulating fluidized bed gasifier is used to generate fuel gas, and the bottom of the fluidized bed of the gasifier has a separate built-in fluidized bed used as a fly ash combustion and reflux space;

(2) An inertial separator is provided on the upper side of the gasifier, the air inlet of the inertial separator is connected with the gas outlet of the gasifier, and the fly ash return pipe is provided at the lower part to lead into the built-in flow of the gasifier. Chemical bed;

(2.1) There is a built-in air preheater in the inertia separator, and the air required by the gasification furnace is preheated by the air preheater and then sent to the air distribution chamber of the fluidized bed of the gasification furnace;

(3) A multi-stage gas purification system is composed of a cyclone separator, a venturi tube, and a water washing tower. The gas separated by the inertial separator is sent to the cyclone separator, and the gas after dust removal by the cyclone separator is sent to the venturi tube , the gas is sent to the water washing tower after cooling and washing off part of the tar in the Venturi tube, and the gas is sent to the gas storage tank by the induced draft fan after further cooling and removing the tar in the water washing tower;

(4) It has a sewage treatment and circulation system. The waste water discharged from the Venturi tube and the water washing tower is re-pumped into the Venturi tube and the water washing tower for recycling after being treated in the sewage treatment tank.

The circulating fluidized bed gasifier with a built-in fluidized bed in the system and the inertial separator with a built-in air preheater can be combined to form an integrated structure, that is, an air preheated circulating fluidized bed gasifier is formed. The gasifier integrates multiple functions of biomass gasification, separation of fly ash in the gas, returning the separated fly ash to the gasifier for combustion, and preheating the air supplied to the gasifier.

The water washing towers in the system can be more than one in series for multi-stage gas purification according to the needs.

The sewage treatment tank in the system can process the sewage discharged from the Venturi tube and the washing tower through the process of cascading gas, adsorption and filtration, and then convert it into clean water for recycling by the Venturi tube and the washing tower.

The unique design adopted by this invention has the characteristics of wide applicability, large adjustable range and high technical performance. It can process several kinds of waste materials separately or simultaneously, including sawdust, chaff, straw or bagasse, etc. The amount can be from 10 tons to 200 tons, and the gas produced can generate electricity from hundreds of kW to several thousand kW, and has low water consumption and high thermal efficiency (greater than 16%).

The following are drawings and drawings of the present invention:

Fig. 1 is a structural representation and a flow chart of the overall system of the present invention;

Fig. 2 is the structural representation of air preheating type circulating fluidized bed gasifier part of the present invention;

Fig. 3 is a sectional view along the line A-B-C-D of Fig. 2 .

In the figure, 1 is an air preheating circulating fluidized bed gasifier, 2 is a cyclone separator, 3 is a venturi tube, 4 is a water washing tower, 5 is a gas storage tank, 6 is a sewage treatment tank, and 7 is a gas pilot Fan, 8 is the circulating water pump, 9 is the air blower, 10 is the feeder, 11 is the circulating fluidized bed gasifier, 12 is the inertial separator, 111 is the main bed of the fluidized bed, 112 is the built-in fluidized bed, 113 is Main bed air distribution chamber, 114 is a built-in fluidized bed air distribution chamber, 121 is a fly ash return pipe, 122 is a built-in air preheater, 123 is an ash baffle, and 124, 125 are regulating air valves.

Embodiments of the present invention are described in further detail below in conjunction with accompanying drawings:

As shown in the overall structure and flow of the biomass circulating fluidized bed gasification purification system in Figure 1, the system consists of three parts:

(1), using air preheating circulating fluidized bed gasifier 1 as biomass gasification device, its structure is shown in Figure 2 and Figure 3, including circulating fluidized bed 11 parts and inertial separator 12 parts, circulation The furnace body of the fluidized bed 11 is a square structure, and the bottom of the fluidized bed is divided into two parts: the main fluidized bed 111 and the built-in fluidized bed 112. The main bed 111 is a biomass gasification and combustion space, and the built-in fluidized bed 112 is the fly ash burning and reflux space, the main bed 111 and the bottom of the built-in fluidized bed 112 respectively have an air distribution chamber (113, 114), between the main bed 111 and the air distribution chamber 113 and the built-in fluidized bed 112 and Distributing plates are arranged between the air distribution chambers 114, and the feeding port is located above the main bed 111. The gasified biomass material is fed into the feeding port by the feeder 10, and an inertial separation device is provided at the gas outlet on the upper part of the gasifier. There are multiple rows of ash baffles 123 in the inertia separator, air preheating pipes are installed on each ash baffle as the built-in air preheater 122, and the fly ash return pipe 121 is installed in the lower part of the inertia separator to lead into the built-in fluidization Bed 112, the air required for gasification is sent out by the air blower 9, preheated to about 150°C-200°C by the built-in air preheater 112 in the inertial separator 12, and then sent to The main bed and the air distribution room with a built-in fluidized bed enter the gasifier through the distribution plate for gasification and combustion.

(2), the gas purification system also includes a cyclone separator 2, a Venturi tube 3 and two washing towers 4 in addition to the inertial separator 12, forming a multi-stage gas purification system, and its gas purification process is: through inertial separation The gas separated by the device 12 is sent to the cyclone separator 2, and the gas after the dedusting treatment of the cyclone separator 2 is sent to the Venturi tube 3, and the gas is cooled to about 80°C in the Venturi tube 3, and part of the tar is washed off before being sent to After entering the water washing tower 4, the gas is sent to the gas storage tank 5 by the gas induced draft fan 7 after being further cooled and tar removed in the two-stage water washing tower. The gas in the gas storage tank 5 can be sent to gas internal combustion engine or gas engine to use at last.

(3), sewage treatment and circulation system, the waste water discharged by Venturi pipe 3 and water washing tower 4 flows into sewage treatment tank 6, and after cascading gas, adsorption and filtration, it is converted into clean water again, and then circulated by water circulation pump 8 Pumped into Venturi tube and water washing tower for recycling. The adsorption material used in the adsorption treatment process of the sewage treatment pool can be chaff ash or biochar produced by the gasification furnace.

Claims (2)

1. a biomass gasifying and purifying circular fluid-bed system has the vapourizing furnace of generation combustion gas and the water washing cleaning device of combustion gas, it is characterized in that:

(1), adopt circle fluidized-bed gasification furnace (11) to generate combustion gas, burning and the built-in fluidized-bed of the spatial that refluxes (112) as flying dust of separating is arranged at the fluidized-bed bottom of this vapourizing furnace;

(2), be provided with an inertial separator (12), the inlet mouth of this inertial separator links to each other with the gas outlet of vapourizing furnace, and its underpart has the built-in fluidized-bed (112) that ash return pipe road (121) feeds vapourizing furnace in the upper side of vapourizing furnace;

(2.1), in inertial separator, be provided with built-in air preheater (122), the vapourizing furnace required air is sent into the air compartment of vapourizing furnace fluidized-bed after this air preheater preheating;

(3), by cyclonic separator (2), Venturi tube (3), the multistage gas-purification of water wash column (4) formation system, send into cyclonic separator (2) through the combustion gas that inertial separator (12) is separated, Venturi tube (3) is sent in combustion gas after cyclonic separator (2) dust removal process, combustion gas in Venturi tube (3) through the cooling and flush away part tar after send into water wash column (4), combustion gas in water wash column through further cool off and remove tar after send into gas-holder (5) by induced draft fan;

(4), have the sewage disposal and a recycle system thereof, the waste water of being discharged by Venturi tube (3) and water wash column (4) is pumped into Venturi tube again after treatment tank (6) is handled and water wash column recycles.

2. biomass gasifying and purifying circular fluid-bed system according to claim 1 is characterized in that said biomass circulating fluid bed gasification furnace (11) combines the preheating of air formula circle fluidized-bed gasification furnace (1) that constitutes integral structure with inertial separator (12).

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