RU2459144C1 - Multi-stage decomposition method of solid fuel by means of oxidation, and device for its implementation - Google Patents

Abstract

FIELD: power industry.

SUBSTANCE: solid fuel is supplied continuously to cylindrical housing 1 with screw 3 with variable pitch along the axis, and is directed to pre-compression zone 4, with simultaneous compaction and sealing of that zone. Then, fuel is supplied to oxidation and pre-heating zone 5 with temperature of 350-750°C, pressure of 0-1 MPa and oxidiser inlet through branch pipe 8a, and after that, to zone of the main metered oxidation 6 with temperature of 500-1000°C, pressure of 0.5-5 MPa and oxidiser inlet through branch pipe 8B, and then - to negative pressure zone 7 with temperature of 700-1500°C, pressure of 0-(-0.9) MPa and oxidiser inlet through branch pipe 8c. Then, ash residue is discharged through one of connection pipes 10 in cylindrical housing 1, and exit gas with the specified physical and chemical properties - through the other connection pipe 9. Method is implemented in solid-fuel converter consisting of receiving bunker 2, cylindrical housing 1 with internal screw 3 with variable pitch and breaks in oxidation zones; oxidiser supply branch pipes 8a, 8B, 8c are made above oxidation zones, on opposite end of housing 1 there located is gas outlet branch pipe 9 with the specified characteristics with vacuum pump located inside branch pipe and ash residue outlet branch pipe 10. At that, shaft of screw 3 is hollow and meant for supply of cooling liquid and is located on bearings with tension device and made in the form of spring for elimination of deflection and for tension of shaft.

EFFECT: invention provides generation of heat energy, combustible gases, synthesis gas with various properties and characteristics for further conversion to liquid synthetic fuel.

2 cl, 1 dwg

Description

The invention relates to energy, and in particular to methods for producing thermal energy by decomposing solid fuel in an oxidizing agent.

A known method of producing thermal energy by burning fuel in an oxidizing agent is RF patent No. 2291349, IPC F23B 10/00 of 01/01/2010.

In the fuel cycle, which is based on the burning of fossil fuels, organize the cycle of fossil fuels and its oxidizing agent, which use elemental fluorine. To do this, inorganic fuel is introduced into the process in the form of silicon dioxide or rare metal oxide belonging to the refractory group and forming a volatile compound with fluorine, it is burned using carbon tetrafluoride formed as a result of combustion of organic fuel. From the resulting combustion products, namely silicon fluoride or rare metal fluoride, silicon or rare metal is reduced to obtain elemental fluorine, and pure carbon is produced from carbon dioxide, also using elemental fluorine and reduced silicon or metal, directing it, just like elemental fluorine, on an initial carbon burning operation.

The disadvantage of this method is that combustion occurs in space using elemental fluorine as an oxidizing agent, and inorganic fuel is introduced into the process in the form of silicon dioxide.

A known method of burning and dry distillation of solid fuel, taken as a prototype - RF patent No. 2319065, IPC F23B 30/00 from 03/10/2002. The method includes loading fuel into the chamber, heating it to the exit temperature of the volatiles, separating the vapor and solid phases and burning the latter in the furnace, and, before placing the fuel in the chamber, it is heated from the inside above the temperature at which the bulk of the volatiles exit.

The disadvantage of this method is the batching rate of combustion and the inability to control the completeness and depth of combustion of the fuel, as well as the inability to control the release of thermal energy, the inability to receive and discharge flue gas for its further use.

Known gasifier for gasification of wood waste, RF patent No. 2341727, IPC F23B 30/00, C10J 03/20 from 04.03.2005. The gas generator comprises a lined case with drying of sawdust in the upper part and a coaxially mounted casing. The casing forms a “shirt” with the body. The throttle nozzle is connected to the inside of the coaxial pipe in communication with the combustion chamber located at the level of the tuyere belt. A sawdust vibratory fluidization device, equipped with an eccentric type vibrator and located below the tuyere belt in the recovery chamber, is located in the housing, and a replaceable ash pan grate with an ash pan chamber is located under the vibratory fluidization device.

The disadvantage of a gas generator is that only sawdust with preliminary drying is used as a raw material, and an external heat source is used throughout the process, which leads to a low efficiency of the device.

The closest is a device for the processing of solid fossil fuels, RF patent No. 2342421, IPC СВВ 53/06. The device comprises a reactor at the inlet connected to the feed hopper, at the outlet, with an outlet channel for the gas-vapor mixture, a furnace equipped with an outlet channel, and a feeder located in front of the furnace. The reactor comprises a housing with a mechanism disposed therein for mixing and moving solid fuel with an auger along the length of the housing. The housing is connected to a sealing chamber.

The disadvantage of this device is that it does not allow to take into account the peculiarity of the feedstock and, as a result, the quality of the outlet gas, the reactions that take place are not controlled, and external heat sources participate in the process throughout the entire period.

The objective of the invention is the creation of an effective method and device for the decomposition of solid fuel and the receipt of thermal energy, flue gas and synthesis gas with desired physicochemical properties, temperature, pressure.

The method of multi-stage decomposition of solid fuel by oxidation involves the continuous supply of fuel into a cylindrical body with preliminary compression and heating of the original fuel to the temperature of the onset of an active oxidation reaction. Fuel is supplied by moving it with a screw along the axis of the oxidation and preheating zone with a temperature of 350-750 ° C and a pressure of 0-1 MPa, a zone of basic oxidation with a temperature of 500-1000 ° C, a pressure of 0.5-5 MPa. Further, the fuel is fed into the discharge zone with a temperature of 700-1500 ° C and a pressure of 0 - (- 0.9) MPa. After the discharge zone, an ash residue leaves through one nozzle, and an exhaust gas with specified physicochemical properties passes through the other nozzle.

A device for implementing the method - a solid fuel converter - consists of a receiving hopper, a cylindrical body with a screw located inside with a variable pitch and breaks in the oxidation zones. Over the oxidation zones made the input pipe of the oxidizing agent. At the opposite end of the casing there is a gas outlet pipe with predetermined characteristics with a vacuum pump located inside the pipe and an ash residue discharge pipe. To supply coolant, the auger shaft is hollow. To eliminate sagging and tensioning, the shaft is located on bearings with a tensioning device in the form of a spring.

Figure 1 shows a solid fuel converter, consisting of a cylindrical housing 1, a receiving hopper 2 with a screw located at a variable pitch 3. The cylindrical housing 1 is divided into a pre-compression zone 4, a pre-heated oxidation zone 5, a main oxidation zone 6 and a vacuum zone 7. In a cylindrical body above the oxidation zones, oxidizer inlet pipes 8a, 8b, 8c are made. At the opposite end of the housing behind the discharge zone 7, a gas outlet pipe with specified characteristics 9, a pipe for removing ash residue 10 are made. The screw shaft is hollow and is located on the bearings, ensuring normal operation of the shaft when it is heated.

The method of multi-stage decomposition of solid fuel is carried out in a fuel converter. In its cylindrical body 1 through the hopper 2 using a screw with a variable pitch 3 serves solid fuel, including carbon and nitrogen compounds. The screw 3, having a variable pitch in the pre-compression zone 4, compresses the fuel with its simultaneous compaction and sealing of this zone.

In the oxidation zone with preheating 5, the fuel is heated to a temperature of 350-750 ° C, with a pressure of 0-1 MPa, and an oxidizing agent is supplied through the pipe 8a.

As a result of this, the temperature and pressure increase in the pre-compression zone 4 and the oxidation zone with pre-heating 5. The heat is removed, and the gas released, together with the fuel residues, moves to the next zone of the main metered oxidation 6 with a temperature of 500-1000 ° С, pressure 0.5 -5 MPa and the supply of the oxidizing agent through the pipe 8 in, where the process is repeated. In the discharge zone 7 with a temperature of 700-1500 ° C, a pressure of 0 - (- 0.9) MPa and the supply of an oxidizing agent through the pipe 8c, the remaining fuel is degassed. At the outlet of the discharge zone 7, negative pressure is created to accelerate the removal of the gas component from the ash residue.

To slow down or accelerate the oxidation reaction in different zones, various amounts of oxidant supply are provided through the nozzles 8a, 8b, 8c. The main oxidizing agent is oxygen and ozone is used as an additive.

Further, through the pipe 9, the gas is discharged for the necessary needs, and through the pipe 10 the ash residue is discharged into the hopper for further disposal.

A solid fuel converter is used as a source of thermal energy, flue gas and synthesis gas, or as a source of obtaining various combinations of the above products.

The advantage over existing methods and devices is low metal consumption, an external energy source is necessary only at the time of starting the oxidation reactions, control over the speed and completeness of oxidation. In the proposed technical solutions, there is an increased extraction of carbon and nitrogen from the feedstock and the production of gas with specified physicochemical properties for further conversion to liquid synthetic fuel.

Claims (2)

1. The method of multi-stage decomposition of solid fuel by oxidation, comprising supplying fuel to the housing, pre-compressing and heating it to the temperature of the onset of an active oxidation reaction, characterized in that the fuel is continuously fed into the cylindrical housing, moving it with a screw with a variable pitch along the axis, and sequentially direct into the pre-compression zone with simultaneous compaction and sealing of this zone into the oxidation and pre-heating zone with a temperature of 350-750 ° C, a pressure of 0-1 MPa, the introduction of an oxidizing agent through a nozzle into the zone of the main dosed oxidation with a temperature of 500-1000 ° С, a pressure of 0.5-5 MPa, an oxidizing agent through a nozzle into the rarefaction zone with a temperature of 700-1500 ° С, a pressure of 0 - (- 0.9) MPa, and the oxidizing agent through the nozzle and then through one of the nozzles in a cylindrical casing remove the ash residue, and through the other nozzle - the outlet gas with the specified physicochemical properties. 2. A solid fuel converter for implementing the method according to claim 1, consisting of a receiving hopper, a housing with a screw located inside, characterized in that the housing is cylindrical, the screw located therein has a variable pitch and breaks in the oxidation zones, input pipes are made over the oxidation zones oxidizer, at the opposite end of the housing there is a gas outlet pipe with predetermined characteristics with a vacuum pump inside the nozzle and an ash residue outlet pipe, and the screw shaft is made hollow for I coolant and located in bearings with a tensioning device as a spring to eliminate sagging and for tensioning shaft.