SU1626044A1 - Lighting-up of a fluid-bed furnace - Google Patents

Abstract

Invention m. used when burning solid fuels in fluidized bed furnaces. The aim of the invention is to reduce the duration of the ignition process. The method of ignition of the fluidized bed furnace consists in the formation of a dense layer consisting of fuel and layer material, the ratio of which is chosen at the rate of 0.04-0.08 tons of equivalent fuel per one ton of layer material. layer. After the ignition temperature is reached, the initial air flow rate is increased according to the ratio proposed. This reduces startup time and ensures its stability.

Description

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The invention relates to energy and can be used to reduce solid fuels in fluidized bed furnaces.

The purpose of the invention is to reduce the duration of ignition.

Example. The experiment is conducted on a pilot plant with an air distribution grid area of 2 m. Slag from under energy boilers with liquid slag removal, fraction from 1 to 5 mm is used as a layer material. Brown coal is used as fuel, which enters the plant after the crusher (fraction from 0 to 13 mm), the thermal equivalent of a ton of equivalent fuel is 1.95 tons of coal. The weight of the material layer is about 800 kg. Coal is loaded from the fuel delivery system onto the bed. The layer is then fluidized for 3-5 minutes. During this operation, the bed and fuel material is uniformly mixed. After this layer

Heated to the ignition temperature of the fuel (320 ° C), passing through a heat exchanger located in the bed, hot steam with a temperature of 420 ° C. At the same time, air passes through the furnace at a linear velocity of about 0.1 m / s, which is substantially less than the critical fluidization velocity. After the layer has reached the ignition temperature of the fuel, the air flow is increased to a design value that ensures a steady fluidization. Moreover, the optimum fuel consumption is determined on the basis of 0.04-0.08 tons of fuel equivalent (tons of oil equivalent) per ton of bed material. If the fuel is injected insufficiently (less than 0.04 tonnes of fuel equivalent), then when the layer is transferred to a fluidized state, its material begins to cool and ignition does not occur. If fuel is injected more than 0.09 tons in tons, then excessive heating of the bed material and the boiler unit structures occurs. The increase in air consumption according to

ABOUT

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J

 (T-Tz)

where G GKP is the current and critical (at the beginning of fluidization) air flow, nm / s;

E is the activation energy of combustion, J / mol-K;

T, Ts - the current temperature of the bed and the ignition temperature of the fuel, K, allows, with the same fuel load, to reduce the duration of kindling by 1.5 times. Thus, the proposed method provides steady and reduced ignition time.

Claims (1)

The invention The method of igniting a fluidized bed furnace, consisting in the formation of a dense layer consisting of particles of inert material and fuel, heating the layer to the ignition temperature of the fuel at one time lower air supply and . a subsequent increase in the flow rate of the air for fluidizing the bed, characterized in that, in order to reduce the duration of the ignition process, the fuel is evenly distributed throughout the bed volume by briefly increasing the feed rate of the air for fluidizing the bed, while 0.08 tons of equivalent fuel per 10 1 t of the bed material, and the increase in air flow for fluidizing the bed is determined from the ratio  + SG-Tz), 15 where G, Skr - current and critical (at the beginning of fluidization) air flow, nm / s; E is the activation energy of the combustion reaction, J / mol K; T, Tz of the layer temperature and ignition of the fuel, K. 20