SU1754760A1 - Method for thermal processing of high-ash fuel - Google Patents

Abstract

The method of thermal processing of high-ash fuels Solid fuel is dried with flue gases, heated by circulating ash heat carrier to form a vapor-gas mixture and coke-ash residue. The vapor-gas mixture is purified from mechanical impurities and condensed to give off resin and semi-coking gas. The coke-ash residue in the air stream is blown to form a gas suspension. Gas suspension in cyclone separators is burned for ashes removed from the process, flue gases supplied to the dry sludge and ash heat carrier supplied to the heating stage. The mass of the ash heat carrier supplied to the heating stage is regulated by introducing an additional gas flow to the gas separation stage. The additional gas flow is not more than 10% of the gas suspension volume. Superheated steam, flue gases, air, or mixtures thereof are used as an additional gas stream. When using as part of the gas flow, flue gases withdrawn from the stage of separation of the gas suspension, before being introduced into the stage of separation, they are fed into the flow of the gas suspension 2 sludge. (Ls

Description

The invention relates to the thermal processing of high-ash fuels and can be used in processes for the processing of solid combustible minerals, as well as in the energy sector in the energy technology use of fuels in power plants.

There is a known method of burning solid crushed fuel by thermal processing to produce coke and combustible gases, separating them, and then separately burning these products. In this case, to heat the fuel, a circulating ash heat carrier is used, and the mass of the returned heat carrier is controlled by means of a separating device placed on

the flow of the heated bulk material consisting of the ash heat carrier returned to the reactor and the ash removed from the installation. A flow divider is installed directly downstream of the ash cyclone, and the entire stream of particles collected is mechanically divided into two parts.

A known unit for thermal processing of shale with a solid coolant, which implemented a method of thermal processing of high-ash fuel (combustible shale), includes the stage of drying the fuel, heating it with a circulating ash heat carrier to form a vapor-gas mixture and coke-ash residue, cleaning the vapor-gas mixture from mechanical impurities and XI

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the following condensation with the release of tar and semi-coking gas, burning of coke-coal residue in air preheater blowing with formation of gas suspension, separation of gas suspension in cyclone separators into ash discharged from the process, flue gases returned to the drying stage, and ash heat carrier supplied to the heating stage with the regulation of its mass.

The purpose of the invention is to simplify the technology of fuel processing while reducing the content of mechanical primers in smolg and reducing the proportion of large particles in the ash.

The goal is achieved by controlling the mass of the ash heat carrier by introducing a dbpolicy gas stream to the stage of separation of the gas suspension. The volume of the additional gas stream is no more than 10% of the gas suspension, as the additional gas stream using superheated water vapor, flue gases , air or mixtures thereof,

As an additional gas flow, a part of the flue gases removed from the gas separation stage is used, and, before being introduced into the separation stage, a gas suspension flow is supplied.

Figures 1 and 2 show the installation scheme where the proposed method of thermal processing of multi-ash fuels can be carried out.

The installation includes a dryer 1, connected by pipeline to the separator 2 dry slate. The dust outlet pipe of the latter is connected to the reactor 3. The circulation circuit of the coolants combines the reactor 3, the separator 4, and the aero phytoheater. B. On the other hand, the condensate separation section of the gas-and-gas mixture is connected to the reactor. 5 Gas-exhaust pipe of the heat carrier separator. The pipeline is connected to the ash separator 7, and the latter to the dryer. The blower 8 (figure 1) or the smoke exhauster 9 (figure 2) is connected to the dust outlet of the heat separator.

The method is carried out as follows.

At Ustanoak with a solid coolant - UTG-3000 at the Estonian TPP serves 139 t / h of oil shale with a characteristic of 2600 kcal / kg; Wr 12.4%; particle size 0-20 mm. The shale is dried with flue gases with a temperature of 84 ° C in the air flow layer. A gas extract, consisting of dry shale, evaporated from shale, moisture and spent drying agent with a temperature of 135 ° C, was obtained well with a dry shale, transferred to a stage separated by sludge.

Selected dry shale weighing 121.7 t / h is sent to the reactor for decomposition. For heating the shale, 340 t / h of ash heat carrier with temperature is supplied to the reactor.

5,845 ° C. As a result of mixing these streams in the reactor, the temperature is set at 485 ° C, a volatile vapor-gas mixture is formed — CGL and a non-volatile coke-ash residue — CTO. Gas-vapor mixture - 14,6 t / h in

10 dry, i.e. at a temperature higher than the dew point temperature — 420 ° C, it is purified from fine particles and transferred to the condensation section, where it is separated into tar, podsmolnoy water and semi-coke gas at the temperature of 485 ° C. incineration in the air inlet chamber. In the latter, in the stream of air blowing, the combustible mass of QZO is burned. As a result of burning receive

A 20 gas suspension consisting of 499 m / h of flue gas HAZARD, 340 h / h of circulating heat carrier and 63 t / h of ash with a temperature of 845 ° C. The gas mixture is directed into the heat carrier cyclone, where 340 tons / h of the largest ash particles are separated. To maintain the flow rate of the coolant at the level of 340 t / h while simultaneously separating the particle size flow into the flow of the coolant separated from the cyclone

30 polydisperse bulk material was injected 115 m3 / h (about 23% of the gas suspension) of flue gases taken from the chimney behind an electrostatic precipitator (cleaned and cooled to 80 ° C). Going towards the polydis35 flow of bulk material the flow of air flue gases carries with it the smallest particles, and the largest particles remain in the coolant. The flow of these particles is sent to the reactor

40 Fine particles removed from the stream are mixed with the flue gases and, as a gas suspension, direct this stream to the ash cyclone, where the flue gases are cleared of ash. Allocated ash 63 t / h output with

45 installations, and the cleaned flue gases are directed to the drying of the fuel.

The implementation of the method allows the collector of the gas suspension to almost all larger particles. Particles with sizes larger than 2 mm are practically absent in ash. At the same time, dust particles with sizes less than 0.1–0.2 mm are practically absent in the coolant and the vapor – gas mixture is not contaminated with dust particles 55 of the coolant.

Claims (3)

Claim 1. Method of thermal processing of high-ash fuels, such as oil shale, includes the steps of drying the fuel with flue gases, heating it with a circulating ash heat carrier to form a vapor-gas mixture and coke-ash residue, cleaning the vapor-gas mixture from mechanical impurities and subsequent condensation with separation of the resin. semi-coking gas, burning the coke-ash residue in the air flow blowing with the formation of a gas suspension, separation of the gas suspension in cyclone separators into ash removed from process, the flue gases returned to the drying stage and supplying the ash coolant to the nagging stage with regulation of its mass, from the fact that, in order to simplify the processing technology of the fuel while reducing the content of mechanical impurities in the resin and reducing the proportion of large particles in the ash, regulation the ash heat carrier mass is carried out by introducing an additional gas stream to the stage of separation of the gas suspension. 2. The method according to claim 1, whether or not the amount of additional gas the flow is not more than 10% of the volume of the gas suspension. 3. The method according to claims 1 and 2, characterized in that, as an additional gas flow using superheated steam, flue gases, air, or mixtures thereof. A. The method according to PP.1 and 2, characterized by the fact that as an additional the gas stream uses part of the flue gases removed from the stage of separation of the gas suspension, and before being introduced into the separation stage, they are fed into the gas flow stream. Dyn. gases l / gas -one T Resin TopMo he-- : Figure 1 Smoke. gases FIG. 2