RU2788060C1 - Method for dust preparation at a thermal power plant and a device for its implementation - Google Patents

Abstract

FIELD: thermal power engineering.

SUBSTANCE: group of inventions relates to the field of thermal power engineering, concerns the complex processing and disposal of various types of waste and can be applied at thermal power plants. The method for dust preparation at a thermal power plant consists in grinding solid fuel, separating the resulting crushed pulverized fuel and hot air and supplying pulverized fuel for combustion in the furnace of a steam boiler with the formation of outgoing flue gases, and additionally pyrolysis is carried out in the gasification tank of pre-sorted and crushed solid household waste, the supply of outgoing gases, the formation of generator gas and solid coke residue, generator gas is fed to the burner devices of the steam boiler and used as an auxiliary fuel, and the solid coke residue with solid fuel is crushed in a ball mill with hot air supply for drying, the resulting pulverized combustible mixture with air is fed into a cyclone, separated, the air is discharged into the atmosphere, and the pulverized combustible mixture is fed into an intermediate hopper, after which the pulverized combustible mixture is directed to the burner devices of a steam boiler for combustion. There is also a dust preparation device at the thermal power plant.

EFFECT: efficient production of heat and reduction of solid fuel consumption due to the joint use of solid fuel and solid household waste at a thermal power plant.

5 cl, 1 dwg

Description

The invention relates to the field of thermal power engineering, for the complex processing and disposal of various types of waste and can be applied at thermal power plants.

A known method of burning low-grade fuel, described in the patent RU, "METHOD FOR BURNING LOW-GRADE COAL" No. RU 2 027 951 C1, publ. 01/27/1995, IPC F23C 11/00. METHOD FOR BURNING LOW-GRADE COALS by supplying coal to a reactor, heat treatment to produce combustible gas and coke ash residue, directing combustible gas to burners for combustion and coke ash residue to an air fountain furnace and cleaning combustion products from solid particles, characterized in that, in order to increase economy, the coal bed in the reactor is additionally treated with low-temperature plasma, and the solid particles obtained during cleaning are removed.

The disadvantage of this method is that the solid particles obtained during cleaning are not used, and there is also no possibility of using municipal solid waste as fuel.

Known pulverization schemes with an intermediate bunker of finished dust used for grinding coal, for example:

Fuel supply and dust preparation systems of TPP: Reference manual / Nazmeev Yu.G., Mindaleeva G.R. - M .: MPEI Publishing House, 2005. - 2005. - Pp. 437.

Thermal and nuclear power plants: Handbook / Under the general. ed. V. A. Grigorieva, V. M. Zorina. - 2nd ed., revised. -M.: Energoatomizdat, 1989 - 608 p.: ill. - (Heat power engineering and heat engineering; Book 3). Page 28-39.

Individual scheme of dust preparation with a dust bunker for SHBM "in the book by A.A. Lebedev" Preparation and grinding of fuel at power plants", ed. "Energy", 1969, p.172.

For the prototype, we take the known method of pulverization described in the Book. 3: Thermal and nuclear power plants: a Handbook / [Alkhutov M.S. and etc.]; Under total ed. A.V. Klimenko and V.M. Zorin. - M.: MPEI Publishing House, 2003 (OAO Typ. News). – 29 p.

From the raw coal bunker, the coal is fed into the down-drying device with the help of coal feeders, where it is dried with hot air. Air is taken from the atmosphere by a blower fan and supplied to the boiler air heater, after which hot air with a temperature of about 350 °C is sent from the air heater to the downward drying device. From the downward drying device, hot air and coal enter the ball mill. In it, coal is crushed to a state of dust. The finished dust is sent to the separator by means of the mill fan, in which the finished dust is separated from coarse dust fractions. Coarse fractions of dust are returned for regrinding to the ball mill. From the separator, the finished dust is fed by the mill fan to the cyclone, in which it is separated from the drying agent, after which, after passing through flashers and screens installed under the cyclone to catch chips, the dust enters the intermediate hopper. With the help of changeover valves, the dust from the cyclone can be directed by a reversible auger to the intermediate hoppers of neighboring boilers. Dust feeders are installed under the intermediate hopper, supplying dust to the mixers of the dust pipelines. In mixers, dust is picked up by hot air or exhaust air from a cyclone and transported to the burners of the furnace.

The disadvantage of this prototype is that there is no possibility of using municipal solid waste together with the main fuel in a thermal power plant.

A device for the preparation of pulverized fuel is known, described in the patent RU, "Installation for the preparation of pulverized fuel" No. RU 197 671 U1, publ. 05/21/2020, IPC F23K 1/00 (2006.01). B02C 17/00(2006.01). INSTALLATION FOR PREPARING PULTERED FUEL.

Installation for the preparation of pulverized fuel, consisting of a raw coal bunker and a finished dust bunker, a mill, a separator, gates, a cyclone, a mill fan, a dust pipeline for finished dust, a gate is installed between the ball drum mill and the separator, between the outlet neck of the ball mill and the suction of the mill fan is installed a dust pipeline equipped with a gate, the drum of a ball mill is lined with metal plates inside, made with grooves on each convex section of their wave working surface, while the width of each groove is less than the diameter of the grinding body. The dust pipeline is a pipeline with a diameter of 900 mm to 1000 mm and a wall thickness of 9 mm to 12 mm.

The disadvantage of this analogue is the inability to use municipal solid waste together with the main fuel at a thermal power plant

Known pulverization system, taken as a prototype, described in the Book. 3: Thermal and nuclear power plants: a Handbook / [Alkhutov M.S. and etc.]; Under total ed. A.V. Klimenko and V.M. Zorin. - M.: MPEI Publishing House, 2003 (OAO Typ. News). – 29 p.

An individual pulverizing system with intermediate bins (closed) including: a raw fuel bunker (we have a raw coal bunker) connected in series with gates, a raw fuel feeder, a downward drying device (we have a solid fuel supply channel), a ball mill, a separator, a which is connected to a fuel return point with a flasher valve, a cyclone with an explosive valve installed on it, and also connected to the boiler (we have a steam boiler), a mill fan and a discharge nozzle, a flasher valve, a toggle gate, a reversible auger, a dust bin (we have an intermediate bunker) which is connected to the cyclone by a moisture suction pipeline, a dust feeder (we have feeders), a mixer, a channel for supplying a solid combustible mixture with a burner (we have burners), a boiler (we have a steam boiler), an air heater (we have a heating chamber with a surface heat exchanger ) connected to a blower fan (we have a fan), which with connected to cold and slightly superheated air addition, secondary air duct, as well as mixer, which is connected to hot air duct, connected to cold and slightly superheated air addition and connected to the boiler by flue.

The disadvantage of this prototype is that there is no possibility of using municipal solid waste together with the main fuel in a thermal power plant.

The objective of the invention is the generation of thermal and electrical energy by co-burning gasification products of municipal solid waste with solid fuel in the boilers of power plants.

The technical result consists in the efficient production of heat and the reduction in the consumption of solid fuel, due to the joint use of solid fuel and municipal solid waste at a thermal power plant.

The technical result in part of the method is achieved due to the fact that the method consists in grinding solid fuel with the supply of hot air for drying it, separating the obtained crushed pulverized fuel and hot air and supplying pulverized fuel for combustion in the furnace of a steam boiler, with the formation of flue gases, additionally, pyrolysis is carried out in the waste gasification tank of pre-sorted and crushed municipal solid waste with the supply of exhaust gases, with a temperature of 800–900 ° C, with the formation of generator gas and solid coke residue, and the generator gas is fed through the generator gas supply channel to the burners of the steam boiler and use it as a lighting fuel, and the solid coke residue with solid fuel is crushed in a ball mill with hot air for drying, the resulting pulverized combustible mixture with air is fed into a cyclone, separated into hot air and a combustible pulverized mixture, then into the air is discharged into the atmosphere, and the pulverized combustible mixture is fed into the intermediate hopper, after which the pulverized combustible mixture is directed through the feeders through the solid combustible mixture supply channel to the burners of the steam boiler for combustion.

ASh and semi-anthracite coal grades are used as fuel.

Drying of solid fuels is carried out with hot air at a temperature of not more than 350 ° C, since at a higher temperature, self-ignition of crushed solid fuels is possible.

The technical result in terms of the device is achieved due to the fact that the pulverizing device at a thermal power plant contains a raw coal bunker connected to an air heater and a ball-drum mill by a solid fuel supply channel, and the air heater is connected to a fan, and the ball-drum mill is connected to a cyclone connected to an intermediate bunker, which is connected by a channel for supplying a solid combustible mixture to the burners of the steam boiler, additionally contains a waste gasification tank connected to the steam boiler by a channel for supplying flue gases and a channel for supplying generator gas to the burner device of the steam boiler, and also connected to a ball-and-drum mill by a channel for self-discharging solid coke residue, the air heater is made in the form of a preheating chamber with a surface heat exchanger, in the upper part of the cyclone there is a branch pipe for air discharge.

Based on the component composition, as well as when modeling the process of gasification of municipal solid waste, several types of municipal solid waste were selected that can be processed according to the scheme proposed in this patent, namely: uncontaminated packaging cardboard waste; waste of low-value wood; straw; sunflower husk; sunflower meal; food waste from kitchens and public catering organizations, unsorted; waste of cleaning vegetable raw materials; uncontaminated packaging paper waste; wooden containers that have lost their consumer properties.

In FIG. 1 shows a pulverizing device at a thermal power plant

The pulverizing device at the TPP contains a bunker of raw coal 8 connected to an air heater and a ball-drum mill 6 by a solid fuel supply channel 12, and the air heater is connected to a fan 11, and the ball-drum mill 6 is connected to a cyclone 13, on which a branch pipe 15 is installed. The cyclone 13 is connected to an intermediate hopper 14, which is connected by a channel for supplying a solid combustible mixture 17 with burners 4 of a steam boiler 2. The device is additionally equipped with a gasification tank for domestic solid waste 1 connected to a steam boiler 2 by an exhaust gas supply channel 5 and a generator gas supply channel 3, and also connected to ball mill 6 with a channel for self-discharging of solid coke residue 7, the air heater is made in the form of a heating chamber 9 with a surface heat exchanger 10.

We will consider the operation of the device using the example of a specific implementation of the method of pulverization at thermal power plants.

From the downcomer gas duct (not indicated in the figure) of the steam boiler 2, the exhaust gas with a temperature range of 800–900 ° C is sent to the gasification tank for municipal solid waste 1 from the downcomer (not indicated in the figure) of the steam boiler 2, where municipal solid waste is also supplied, which has previously undergone preliminary sorting and grinding to the size of 10x10 mm. In the solid domestic waste gasification tank 1, the process of high-temperature waste pyrolysis takes place without oxygen access with a temperature range of 800 - 900 °C. As a result of pyrolysis, gasification of municipal solid waste occurs with the formation of producer gas and solid coke residue. Producer gas through the generator gas supply channel 3 is supplied to the burner devices 4 for use as a lighting fuel, which, due to its high calorific value, is used to initiate the combustion process of low-grade fuel, for example, Donetsk ASH for NchGRES, PJSC Branch, "OGK-2" . The solid coke residue in its structure similar to coal (black, brittle) and having combustible properties is fed into the ball-drum mill 6 by self-discharging through the channel of self-discharging solid coke residue 7. Solid fuel - coal and a drying agent are also fed into the ball-drum mill 6 through the existing on the power unit fuel supply systems (not shown in Fig.). The drying agent is hot air with a temperature of about 350 ° C, recommended for ASh and semi-anthracite coal grades; at a higher temperature, self-ignition of crushed solid fuel is possible. Air is taken from the atmosphere with the help of fans 11 and heated in a surface heat exchanger 10 installed in the preheating chamber 9. Hot exhaust gas is supplied to the preheating chamber 9 from the downcomer (not indicated in Fig.) of the steam boiler 2, which gives off its heat through the walls of the surface heat exchanger 10 air. Further, hot air through the solid fuel supply channel 12 enters the ball-drum mill 6 with the help of fans 11. Coal enters from the raw coal hopper 8 through the solid fuel supply channel 12 into the ball-drum mill 6. In the ball-drum mill 6, the solid coke residue is mixed with the main fuel - coal , ground to the required fineness (R ₉₀ in the range 6-10) and dried with hot air. After that, the resulting pulverized combustible mixture with air is fed into cyclone 13. In cyclone 13, due to centrifugal forces and the difference in masses of the pulverized combustible mixture and air, the second one is separated from the first one and further, by means of fans (not shown in Fig.) the air is discharged into atmosphere through the pipe 15, and the pulverized combustible mixture (coal and solid coke residue of municipal solid waste) is sent to the intermediate hopper 14, after which it is sent to the burner devices 4 through the feeders 16 through the channel for supplying the solid combustible mixture 17.

Thus, the method described above makes it possible to burn the products of gasification of municipal solid waste together with solid fuel in boilers of power plants for the subsequent generation of heat and electricity. Co-combustion of solid fuel and municipal solid waste reduces the consumption of solid fuel by the boiler of the power plant.

Claims (5)

1. The method of pulverizing at a thermal power plant, which consists in grinding solid fuel with the supply of hot air for drying it, separating the obtained pulverized pulverized fuel and hot air, and supplying the pulverized fuel for combustion in the furnace of a steam boiler with the formation of flue gases, characterized in that it is additionally carried out pyrolysis in the waste gasification tank of pre-sorted and crushed municipal solid waste with the supply of exhaust gases at a temperature of 800-900 ° C with the formation of generator gas and solid coke residue, and the generator gas is fed through the generator gas supply channel to the burners of the steam boiler and used in as a lighting fuel, and the solid coke residue with solid fuel is crushed in a ball mill with the supply of hot air for drying, the resulting pulverized combustible mixture with air is fed into a cyclone, separated into hot air and a combustible pulverized mixture, then the air is discharged into the atmosphere. sphere, and the pulverized combustible mixture is fed into the intermediate hopper, after which the pulverized combustible mixture is directed through the feeders through the solid combustible mixture supply channel to the burners of the steam boiler for combustion. 2. A device for pulverizing at a thermal power plant, containing a raw coal bunker connected to an air heater and a ball-drum mill by a solid fuel supply channel, the air heater being connected to a fan, and the ball-drum mill connected to a cyclone connected to an intermediate hopper, which is connected by a solid fuel mixture supply channel to the burners. devices of a steam boiler, characterized in that it additionally contains a waste gasification tank, connected to the steam boiler by a flue gas supply channel and a generator gas supply channel to the burner device of the steam boiler, and also connected to a ball-drum mill by a channel for self-discharging solid coke residue, the air heater is made in the form of a heating chambers with a surface heat exchanger, in the upper part of the cyclone there is a branch pipe for air discharge. 3. The method of pulverization at a thermal power plant according to claim 1, characterized in that ASh and semi-anthracite coal grades are used as fuel. 4. The method of pulverization at a thermal power plant according to claim 1, characterized in that the drying of solid fuel is carried out with hot air with a temperature of not more than 350°C. 5. The dust preparation device at a thermal power plant according to claim 2, characterized in that the following is used as municipal solid waste: uncontaminated packaging cardboard waste, low-value wood waste, straw, sunflower husk, sunflower meal, unsorted food waste from kitchens and public catering organizations, cleaning waste vegetable raw materials, uncontaminated packaging paper waste, wooden containers that have lost their consumer properties.

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