RU2516394C2 - Plant for thermal processing of solid fuels - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to chemical industry and can be used in processing of coal shale and peat. Proposed plant comprises bin (1) with fuel and equipped with feeder (2), fuel mixer (3) and solid heat carrier cyclone (4), drum-type pyrolysis reactor (5) with horizontal shaft, dust separation chamber (6) with dust separation cyclone (9). Outlet of cyclone (9) is connected with compartment (10) of fluid condensation from vapour-gas mix. Bottom of dust separation chamber (6) is connected with inlet of flash firebox (8) its outlet being connected via gas-dust flow splitter (11) with cyclone (4), its ash discharge outlet being connected with fuel and solid heat carrier mixer (3). Outlet of flash firebox (8) is connected with ash separator (12), its ash discharge being connected with ash heat exchange (13) while gas pipe being connected to waste-heat boiler (15). Dust separation chamber (6) is furnished with flow splitter plate (17). One part of plate (17) is arranged in outlet pipe (18) of pyrolysis reactor (5) above solid material layer at the angle of its natural slope. Second part of said plate (17) is arranged in dust separation chamber (6) horizontally to cover is cross-section with slot formation.

EFFECT: higher quality of fluids, simplified dust separation and condensation.

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Description

The invention relates to the field of thermal processing of solid fuels and organo-waste and can be used in the energy sector and other industries to produce high-calorie liquid and gaseous products from solid fuels, such as shale, coal, peat and organo-waste.

A known installation for the thermal processing of oil shale, containing a sequentially installed dryer with a raw material feeder, a separator of spent drying agent, connected to a screw that feeds the dried raw materials to the mixer of solid coolant and shale, connected to a pyrolysis reactor, the outlet pipe of which is connected to a dust-collecting chamber, the vapor-gas outlet mixture from which through the device for cleaning solid particles is connected to the condensation unit, and the output of the coke residue, by means of a screw pi STUDIO is connected to the air-fountain combustion chamber, the output of which is connected to the flow divider, the gas output is connected to an ash cyclone and then with a waste-heat boiler and zolospusknoy output is connected to the cyclone, the collecting ash used as the solid coolant. [The journal "Proceedings of the Academy of Sciences. Energy," No. 6, 2000, p.126].

Also known is a plant for the thermal processing of solid fuels, for example oil shale, containing a sequentially installed fuel hopper with a feeder, a fuel and solid coolant mixer, a pyrolysis reactor, a dust collection chamber with a cyclone associated with a vapor-gas mixture condensation device and an aerial fountain, the output of which is connected to a flow divider, the ash output of which is connected to the cyclone of the solid coolant; and the gas outlet is connected to the ash separator and after it to the recovery boiler, and the ash outlet of the ash separator is introduced into the ash heat exchanger. [RF patent No. 2360942 of 05.15.2008, class. СВВ 53/06, 49/16.].

The disadvantages of these plants are that from the pyrolysis reactor, through its outlet pipe, a combined gaseous stream of a gas-vapor mixture and a solid material — a mixture of semi-coke and coolant ash — enters the dust chamber. Due to the fact that the process uses fuel of polydisperse particle size distribution, as well as due to the abrasion of fuel and ash particles during their movement and pouring, a large number of small particles (dust) are always present in the gas-vapor mixture in the gas volume of the pyrolysis reactor. Since the velocity of the dust-gas stream in the outlet pipe of the reactor entering the dust-collecting chamber reaches 6 m / s, small particles of the solid phase are involved and carried away into the dust-collecting chamber, which significantly increases the total dust content of the vapor-gas mixture that goes further to the condensation compartment. As a result, despite the dust cleaning device (cyclone) existing in the dust chamber, the heavy resin fraction (oil) obtained as a commercial product contains an increased amount of mechanical impurities (up to 3 wt.%) [Standard of the enterprise. Shale oil manufactured at the Estonian power plant EE10421629 ST4: 98].

The technical result, the solution of which the claimed device is directed, is to improve the quality of liquid products and simplify dust cleaning and condensation systems by reducing the dustiness of the vapor-gas mixture entering the dust collecting chamber.

The technical result is achieved by the fact that in the installation for thermal processing of solid fuel containing a prepared fuel hopper with a feeder, a fuel and solid coolant mixer, a drum-type pyrolysis reactor with a horizontal axis of rotation, a dust collecting chamber with a dust cleaning cyclone, the exhaust pipe of which is connected to the liquid condensation compartment products from the gas-vapor mixture, and the lower part of the dust precipitation chamber is connected to the entrance to the airborne firebox, the exit from which through the flow divider the ash outlet from which is connected to the fuel and solid heat carrier mixer is connected to the cyclone of the solid heat carrier, and the gas outlet is connected to the ash separator, the ash outlet of which is connected to the ash heat exchanger, and the gas outlet is connected to the recovery boiler, the dust collecting chamber is equipped with a flow division plate, one part of which is placed in the outlet pipe of the pyrolysis reactor above the layer of solid material located there at an angle of repose of the material, and the other part of the plate is It is shown in the dust collecting chamber that the dust collecting chamber is provided with a flow dividing plate, one part of which is placed in the outlet pipe of the pyrolysis reactor above the layer of solid material located there at an angle of repose of this material, and the other part of the plate is placed horizontally in the dust collecting chamber and overlapping its cross section with the formation of a gap located at the wall opposite the inlet of the pyrolysis reactor.

Providing a dust separation chamber with a flow dividing plate, a part of which is located directly above the layer of solid material located in the pipe at an angle of its natural slope, allows you to separate the flows of solid and gaseous products at their entrance to the outlet pipe of the pyrolysis reactor. As a result, the main gaseous stream of the vapor-gas mixture, moving with increased speed above the plate, does not come into contact with solid material, which excludes the capture of small particles and their entrainment. At the same time, the flow of solid material, moving under the plate without the disturbing effect of the gas stream, quietly moves under the influence of gravity to the lower part of the dust chamber. A small amount of residual gases released from the solid phase in the pre-gasification process is evacuated at a low speed to the upper part of the dust-collecting chamber through a gap free from overlap located at the wall opposite the inlet pipe of the pyrolysis reactor and comprising about 1/5 of the cross-sectional area.

The invention is illustrated by drawings, where figure 1 shows a schematic diagram of the proposed installation for thermal processing of solid fuels, figure 2 - placement of the plate dividing flows, and figure 3 - the position of the plate in the inlet pipe.

The installation comprises a prepared fuel hopper 1, for example, oil shale, from which fuel is fed by a feeder 2 to a mixer 3, which is connected to the ash outlet of a cyclone of a solid heat carrier 4 and a pyrolysis reactor 5 connected to a dust collecting chamber 6, the coke-ash outlet of which is connected by a feeder 7 to the entrance to the aerial the furnace 8, and the other exit through the system of cyclones 9 is connected to the condensation compartment of liquid products from the vapor-gas mixture 10. The exit from the airborne furnace 8 is connected via a flow divider 11 to cyclone 4 and nym separator 12 zolospusknoy pipe which is connected with an ash heat exchanger 13, heated air supplied by the blower 14 and the gas pipe connected to the recovery boiler 15 provided with a cleaning device 16, products of combustion from ash. A flow dividing plate 17 is placed in the dust-collecting chamber 6, part of which is placed in the outlet pipe 18 of the pyrolysis reactor 5 over its entire length above the layer of solid material there at an angle of repose of this material, and the other part of the plate is placed horizontally in the dust-collecting chamber and is made to overlap it cross section with the formation of a gap located at the wall opposite the inlet pipe of the pyrolysis reactor.

Installation works as follows.

Prepared fuel, for example shale, with a particle size of 0-15 mm is fed from hopper 1 by feeder 2 to mixer 3, where it begins to mix with a solid heat carrier coming from cyclone 4 at a temperature of 700-800 ° C. A solid ash is used as a solid heat carrier slate. The mixture of shale and coolant enters the pyrolysis reactor 5, where, due to the slow rotation of the reactor (drum), it is finally mixed and heat and mass transfer and thermal decomposition of the organic component of the shale (pyrolysis) take place in an oxygen-free medium with the formation of a vapor-gas mixture and solid coke residue (semi-coke). The gas-vapor mixture after purification of suspended ash particles in the dust-collecting chamber 6 and cyclones 9 is discharged to the condensation section of the gas-vapor mixture 10, where the condensed heavy hydrocarbons form a resin (artificial oil), and the non-condensable part of the gas-vapor mixture forms a semi-coke combustible gas, which is removed from the condensation section 10 for use, for example, in a boiler of a thermal power plant.

The coke residue (semi-coke) formed as a result of pyrolysis, containing a portion of undecomposed organic matter and a mineral component, together with the heat-transfer ash forms a coke-ash residue, which enters the air-fired furnace 8, where its organics are burned in the air stream supplied by the blower 14. As a result of burning organics of the coke-ash residue, the temperature of the resulting gas suspension flow at the outlet of the aero-fountain furnace 8 rises to 700-800 ° C. This high-temperature gas suspension stream enters the stream divider 11, which is divided into two parts: one part enters cyclone 4 to separate the ash, which serves as a coolant, the other through the gas exhaust pipe of cyclone 4 to the ash separator 12, from which the gases purified from the ash are directed to the waste heat boiler 15, and the collected ash is discharged into the ash heat exchanger 13, which heats the air and then is taken out of the cycle. The heat of the stream in the waste heat boiler 15 is used to obtain, for example, a pair of medium parameters, and then electricity.

During the pyrolysis of oil shale in reactor 5, the gas-vapor mixture occupies its free (upper) volume, and the coke-ash residue fills its lower part. Due to the rotation of the reactor 5 (drum) and the difference in layer levels at the inlet of the reactor 5 and in its outlet pipe 18, the coke-ash residue moves axially to the outlet pipe 18, through which it is discharged into the dust chamber 6. Due to friction forces, the material rotating drum 5 rises along one of its walls until it reaches the angle of repose, and then rolls into the lower part. As a result, with a constant rotation of the drum 5, a layer of material is formed in it, the inclination of which to the horizontal is determined by the properties of the material and the speed of rotation of the drum 5. At the entrance to the outlet pipe 18, separated by a plate for dividing the flows 17 into upper and lower parts, the vapor-gas mixture flows to the upper part of the pipe 18, and due to the reduction of the bore, its speed is significantly increased to values exceeding the speed of movement of relatively large particles. But, since the flows of the gas-vapor mixture and the coke-ash residue are separated, the capture of fine solid particles by the gas stream and their removal into the gas volume of the dust-collecting chamber 6 is practically excluded.

The solid material moves under the flow dividing plate 17 and, after exiting the reactor nozzle 18, is poured into the lower part of the dust-collecting chamber 6. The small amount of residual gases released from the semi-coke during the after-gas recovery process at a speed not exceeding 0.1 m / s is quietly evacuated to the upper part of the dust-collecting chamber 6 through a slit located at the wall opposite the inlet pipe of the pyrolysis reactor and constituting approximately 1/5 of the cross-sectional area of the dust-collecting chamber 6. Due to the low speed of If the flow of these gases occurs, capture of small solid particles and their removal into the gas volume of the dust-collecting chamber 6 is practically excluded.

Thus, the claimed technical solution allows to improve the quality of liquid products and to simplify the dust cleaning and condensation systems by reducing the dustiness of the vapor-gas mixture entering the dust collecting chamber.

Claims (1)

Installation for thermal processing of solid fuels, for example oil shale, containing a prepared fuel hopper with a feeder, a fuel and solid coolant mixer, a drum-type pyrolysis reactor with a horizontal axis of rotation, a dust collection chamber with a dust cleaning cyclone, the outlet of which is connected to the condensation unit for liquid products from a gas-vapor mixture, and the lower part of the dust precipitation chamber is connected to the entrance to the aero-fountain furnace, the exit from which through a gas-dust divider the flow is connected to the cyclone of the solid heat carrier, the ash outlet from which is connected to the mixer of fuel and solid heat carrier, and the gas outlet is connected to the ash separator, the ash outlet of which is connected to the ash heat exchanger, and the gas outlet is connected to the recovery boiler, characterized in that the dust collecting the chamber is equipped with a flow dividing plate, one part of which is placed in the outlet pipe of the pyrolysis reactor above the layer of solid material located there at an angle of repose, this material and the other part of the plate placed horizontally in the chamber and pyleosaditelnoy formed overlying its cross-section to form a slit situated at the wall opposite to the inlet of pyrolysis reactor.

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