DD222091A1 - METHOD AND DEVICE FOR LOADING SWIVEL LAYER FIRES WITH SOLID FUELS - Google Patents

Abstract

The invention relates to a method and a device for feeding fluidized bed combustion with solid fuel, in particular raw lignite coal, through a conveyor screw, wherein the fuel with a high moisture content is introduced into the fluidized bed operated under greater pressure. It is to bring the pit-wet fuel with a reliable Brennstoffoerderung, using a Schneckenfoerderers the fluidized bed should be sealed at the same time. According to the invention, this is achieved by a method in which a conveyor screw is used to feed the fluidized bed, which is driven at the same volume flow over its length with different degrees of filling by the degree of filling in the entry part approximately 1 and in the degassing part about 0.3 and in the loading part much larger than in the degassing is. figure

Description

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Title of the invention

Method and apparatus for charging solid fuel fluidized bed combustors

Field of application of the invention

The invention "relates to a method and a device for feeding fluid fuel burners with solid fuel, in particular raw lignite coal, wherein also fuel with high moisture content can be introduced into the pressurized fluidized bed.

Characteristic of the known technical solutions

It is known that the continuous transport of substances with a high water content or high surface moisture in closed mechanical devices is associated with great difficulties and leads to drastic malfunctions. This susceptibility to mechanical devices adjusts to the fact that the moist material, eg. B · Ronbraunkohle, leads to blockages and briquetting and thus brings the promotion to a standstill. For this reason, such substances by additional facilities such as flue gas dryer u. Ä. As far as dried until they can be easily pneumatically required, as in DE-OS 2931 354, Kl. F 23 0,

11/00 "has been described. In a pneumatic conveying, however, the effort for a metered fuel supply line is higher than in comparison to, mechanically metered fuel input. In addition, other fans with high pressure for "required, whereby a non-adjustable air content additionally enters the furnace.

If the substance is introduced using gravitational force with rotary valves over the fluid, the fine grain is whirled up and discharged with the flue gases, which is uneconomical and environmentally harmful.

Object of the invention

The aim of the invention is to introduce solid fuel, in particular raw lignite by means of a reliable mechanical delivery metered into a fluidized bed combustion and thereby avoid environmental pollution and efficiency losses.

Explanation of the essence of the invention

The object of the invention is to provide a method and a device for feeding fluidized bed combustion with solid fuel, in particular raw lignite, wherein the fluid bed is sealed simultaneously with the fuel input using a screw conveyor and a predrying of the fuel can be omitted.

According to the invention this is achieved by a method / in which for feeding the fluidized bed, a screw conveyor is used, which is driven at the same volume flow over its length with different degrees of filling by the degree of filling in the entry part

approx. 1 "and in the degassing section approx. 0.3" and is considerably larger in the charging section than in the degassing section "

The device used for this consists of a. Task part, a degassing and an entry part, wherein the task part is a fuel reservoir is placed directly on the screw housing, the degassing part has a vapor withdrawal and realization of different degrees of filling in a known manner by changing the pitch and / or the diameter ratio D / d is achieved ^v

For centering the overhung short-flight worm has the screw conveyor, which is stored in the region of the fuel storage sbehälters on one side, in the entry part of a double helix.

So that the withdrawn fuel in the degassing has a low degree of filling, the core shaft of the screw conveyor at the task and entry part each have a conical transition, which merges into a smaller core shaft diameter in the degassing.

Embodiment '.

The invention will be explained in more detail below using an exemplary embodiment. In the accompanying drawing, the device is shown as Seitenansicnt in section.

As shown in the drawing, the screw housing Ί is guided horizontally in the fluidized bed of the fluidized bed combustion in the process for charging fluidized bed combustion with solid fuel, in particular with grubenfeuchter raw lignite, the fuel reservoir 3 placed directly on the screw housing 1 at the beginning of the screw conveyor 4 is. This consists of the task part 5 »the degassing 6 and the

Entry part 7. The pre-fractured raw lignite falling from the fuel storage container 3 onto the feed part 5 of the rotating conveyor screw 4 forms a delivery flow with a high degree of filling, which is determined by the speed, pitch and flight depth of the conveyor screw 4. This part works as a discharge screw and goes into In this way, a filling degree of 0.3 is aimed at, which here causes a space of least pressure for a pure drag flow for the degassing part 6. Thus, the over the entry rope 7 incoming abdominal gases and oils due to the increase in temperature in the direction of the fluidized bed resulting vapors are collected and withdrawn.They reach the combustion chamber via the exhaust vent 8, but can also be returned to the exhaust duct.

In the compression zone 9 of the entry part 7 of the flow is compressed to a degree of filling of approximately 1. With this compression is largely prevented that fluid from the fluidized bed and flue gases and Verbrennungsluft.in enter the screw conveyor 4. The one-sided mounted screw conveyor 4 has in its entry part 7 a double helix 10, which causes a centering. Furthermore, a plug disk 11 is arranged in the screw housing 1 between the compression zone 9 and the degassing 6, in order to seal both spaces from each other. This task also has the carbon layer, which is held in the fuel storage tank 3 at a certain layer height. This ensures at the same time that always an approximately the same bulk density is on the task part 5, because often the density of the fuel varies. In addition, it is convenient to install in the entry zone of the screw housing 1 longitudinal grooves, so that the coefficient of friction between the screw housing 1 and the raw lignite is quite large, to make the promotion safe.

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The advantage of the invention "is that despite the use of a screw conveyor, the fluidized bed is sealed at the same time with the fuel input and a predrying of the fuel can be omitted.

Claims (2)

invention claim 1. A method for feeding fluidized bed combustion with solid fuels, in particular raw lignite, wherein the entry location is exposed to the pressure and the temperature of the fluidized bed ^, characterized in that for feeding the fluidized bed, a screw conveyor is used, with the same volume flow over its length with different Filling levels is driven, wherein the degree of filling in the entry part (7) is approximately 1 in the degassing (6) about 0.3 and in the task part (5) is substantially greater than in the degassing (6). 2. Apparatus for carrying out the method according to item 1, characterized in that the conveyor screw (4) consists of a task part (5), a degassing (6) and an entry part (7), wherein the task part (5) a fuel storage container (3 ) is placed directly on the screw housing (i), the degassing (6) has a vapor withdrawal (8), and the realization of the different degrees of filling in a known manner by changing the pitch and / or the diameter ratio D / d is achieved. 3ο device according to item 2, characterized in that the conveyor screw (4), which is mounted on one side in the region of the fuel storage container (3), in the entry part (7) has a double helix (10). 4, device according to point 2 and 3> characterized in that the core shaft of the screw conveyor (4) at the task and entry part (5 »7) each having a conical transition, which merges into a smaller core shaft diameter in the degassing (6). ' For this 1 sheet drawing