RU2293108C1 - Method of production of producer gas and device for realization of this method - Google Patents

Abstract

FIELD: thermal processing of solid fuel.

SUBSTANCE: proposed method consists in pyrolysis and gasifying of solid fuel at temperature of 580-600°C at excess air coefficient of 0.15-0.25; processes are carried out simultaneously in suspended state in single reaction volume. Proposed method includes loading poly-dispersed fuel at size of particles no more than 10 mm followed by tangential feed of flow of air to both reaction zones preheated to temperature not below 300°C at rate of 7-15 nm/s. Air to pyrolysis zone is additionally fed by multi-jet flow directed radially. Flow rate of air is so adjusted that flow rate in gasifying zone exceeds that in pyrolysis zone by 1.5-2.5 times, thus ensuring continuous circulation of fuel till complete combustion. Device proposed for realization of this method has vertical metal housing which is cylindrical in upper and lower parts; in middle part housing is made in form of truncated cone. Housing is provided with cover having fuel loading hatch and with nozzles in pyrolysis and gasifying zones for tangential feed of air flow, system for discharge of producer gas in form of tube with cap located inside housing coaxially relative to it. Wall of housing in pyrolysis zone is provided with through perforations for forming multi-jet flow of air. Proposed method excludes use of refractory materials and special preparation of fuel, enhances ecological safety through reduction of contaminants by 3-5 times. There is no need in special training of attending personnel. Method provides for compensation for expenses for equipment during a period from 2 months to one year. Usage of metal is reduced by 3-7 times and cost of device is reduced by 1.5-3 times as compared with domestic analogs and by 3-5 times as compared with import analogs.

EFFECT: enhanced efficiency; increased service life of device; enhanced ecological safety.

3 cl, 1 dwg, 1 ex

Description

The invention relates to the field of thermal processing of solid fuels (coal, shredded wood waste, plant residues, household and industrial waste, etc.) and can be used in forestry, peat, rural and other farms to produce cheap gaseous fuel (generator gas) used in energy technology installations.

Known methods for producing generator gas (processing of solid fuel), including two-stage processes: gasification of solid fuel and burning of fuel residues.

Devices for implementing these methods include gas generators, boiler units and other devices. [See, for example, Auth. USSR No. 1298479, IPC F 23 B 7/00, 1987; p. of the Russian Federation No. 2099394, IPC C 10 J 3/86, 1997, etc.].

There are also known methods for producing generator gas, including the burning of low-reaction high-calorie fuels (coal, anthracite) at high temperature with liquid slag removal and low-temperature burning of highly reactive low-calorific fuel (sawdust, husk, etc.) while maintaining dry slag removal.

Devices for implementing these methods consist mainly of vertical-type cyclone furnaces in which air tangentially enters the lower part of the cylindrical chamber. Fuel enters the center of the furnace through the top of the chamber. Flue (generator) gases along with ash are discharged to the top of the furnace. Many furnace devices are carried out according to a two-chamber scheme: a gasification chamber and a chamber for complete afterburning of gasification products. [See, for example, G.F. Knorre. Cyclical furnaces, state. energy ed., M. - L., 1958, S. A. Belogurov et al. Cyclone furnace devices for generating heat during the combustion of agricultural biomass in technological processes. Dnepropetrovsk National University, e-mail: fti-dnu@a-teleport.com et al.].

In addition, there are known methods of gas generation by pyrolysis of solid fuel (pyrogenetic process, in which the raw material is heated without air) at a temperature of 600-750 ° C and gasification (thermochemical process of converting the organic mass of fuel into combustible gas due to oxidation by air, vapor-air mixture, steam, steam-oxygen mixture, etc.) at a temperature of more than 1000 ° C.

Devices for implementing these methods consist of various types of gas generators (with a fixed layer of fuel, with a fluidized bed, etc.) and other thermal and auxiliary equipment. [See, for example, paragraphs of the Russian Federation No. 2147601, IPC C 10 J 3/20, 2000; p. RF №2225429, IPC С 10 В 53/08, 2004; p. RF №2242677, IPC С 10 В 53/00, 2004, з. RF №2003112606, IPC C 10 J 3/20, 2004; h. RF №2003137067, IPC F 23 B 1/14, 2005, etc.].

The above-described methods for producing generator gas and devices for their implementation have the following number of common technical disadvantages:

- low efficiency of processes due to incomplete combustion of fuel;

- high temperature of the ongoing processes, requiring the use of refractories and reducing the service life of the devices used and their maintainability;

- the need for fuel preparation (drying wet fuel, sorting by particle size);

- low calorific value of produced gas (not more than 5.5 MJ / m ³ );

- environmental hazard resulting from the release of pollutants into the atmosphere;

- high metal consumption of devices and low efficiency;

- the complexity of the service and the requirement for special training;

- the high price of installations (more than 250,000 rubles for domestic equipment).

The closest domestic analogue of the claimed invention is a method of generating generator gas developed by Thermotech (Bryansk), including the pyrolysis of solid fuel (wood processing waste) at a temperature of 900-1100 ° C.

A device for implementing the analogue method consists of a solid fuel (gas) boiler, a vortex gas generator with a combustion chamber, a feed hopper, a screw conveyor, a gearbox and an electric motor.

Fuel is supplied to the gas generator from below, and primary air from above. The fuel layer gradually moves to the upper part, to the zone of active combustion. During the movement, the fuel is dried, gasified and ignited. For afterburning of burning particles removed from the bed by primary air, secondary air is provided through special channels located tangentially to the combustion chamber. Under the action of centrifugal forces arising from the rotation of air, unburned fuel particles are discarded to the cylindrical walls of the generator and continue to rotate repeatedly until they burn out completely.

The calorific value of the gas obtained is not more than 4.6 MJ / m ³ , efficiency = 0.8, power 250 kW, weight 500 kg, price 250,000 rubles. [Cm. Thermotech company prospectus, http://www.yasen.ru/gazgen.htm]. A copy of the nearest domestic analogue is attached.

The closest analogue described above — the method and installation — allows one to obtain generator gas, but it has traditional disadvantages: high process temperature, cumbersomeness and high metal consumption of the apparatus, as well as high cost.

The closest in technical essence and the achieved result to the claimed invention is a method for producing generator gas by pyrolysis and gasification of solid fuel (vortex gasification), developed by the Danish Technical University, including loading of fuel, tangential flow of a preheated air stream into the pyrolysis zone with simultaneous processes in suspended state in a single reaction volume. Pyrolysis is carried out at a temperature of at least 1100 ° C, and gasification at a temperature of 750-800 ° C. The main components of the resulting gas: CO ₂ , CO, methane, hydrogen, steam, resins.

The device for implementing the prototype method contains a vertical metal case, equipped with a lid with a hatch for loading fuel in the upper part, has nozzles for tangential air flow in the pyrolysis zone and a system for removing the resulting generator gas. The cylinder-shaped device is also equipped with a drying chamber for preparing fuel and a bag filter for cleaning the generator gas from resins. Air and fuel are fed into the housing from above. Fuel in the combustion process moves down and passes through the coal layer. The resulting generator gas is discharged through the bottom of the housing. [Demonstration of the Vortex Process for Biomass Gasifiers. Felicia Fock, Ulrik Henriksen og Kristine Thomsen. Poster and paper V2.82 in proceedings of 12 ^th European Conference and Technology Exhibition on Biomass for Energy, Industry and Climate Protection. Amsterdam June 2002, pp. 670-676. (Demonstration of the process of gasification of biomass. Felicia Fock, Ulrik Henriksen and Christina Thomsen. Publication and article V2.82 written during the 12th European Conference and Technology Exhibition on “Energy from Biomass, Industry and Climate Protection.” Amsterdam, June 2002, p.670-676).] A copy of the prototype in English and the author's translation are attached.

The disadvantages of the method and device prototype:

- low efficiency of processes due to the limited completeness of fuel combustion with the removal of unreacted particles together with the generator gas from the device;

- high temperature processes;

- the need for fuel preparation;

- the complexity of the hardware design;

- insufficient calorific value of the produced gas;

- limited installation efficiency;

- high price (imported technology and equipment).

The present invention is the creation of an effective, environmentally friendly method for producing high-calorie generator gas, carried out on a simple, cheap, affordable mass consumer equipment.

The problem is solved in that in the known method for producing generator gas by pyrolysis and gasification of solid fuel, including loading fuel, tangential supply of a preheated air stream to the pyrolysis zone with simultaneous processes in suspension in a single reaction volume, according to the INVENTION, polydisperse fuel with a size of particles of not more than 10 mm, to which an air flow is supplied at a speed of 7-15 nm / s, heated to a temperature of at least 300 ° C, and in the pyrolysis zone in spirit additionally fed multijet flow directed radially; at the same time, air is also supplied to the gasification zone by a tangential flow having thermodynamic characteristics identical to the pyrolysis zone; pyrolysis and gasification is carried out at a temperature of 580-600 ° C and an excess air coefficient of 0.15-0.25 with the regulation of air flow, which in the gasification zone is 1.5-2.5 times higher than the flow in the pyrolysis zone, which ensures continuous circulation fuel until it is completely burned.

In the known device for producing generator gas, comprising a vertical metal case, provided with a lid with a fuel loading hatch in the upper part, having nozzles for tangential air supply in the pyrolysis zone and an exhaust gas system for extracting the generated gas, ACCORDING TO THE INVENTION in the pyrolysis zone between the nozzles the wall of the body there is a through perforation to create a multi-jet flow, nozzles for tangential air supply are installed in the gasification zone, and the generator gas exhaust system is installed in in the form of a pipe with a cap and located inside the housing coaxially with it.

In the device, ACCORDING TO THE INVENTION, the housing in the upper and lower parts has the shape of a cylinder, and in the middle - a truncated cone.

The implementation of the method of producing generator gas in the claimed conditions eliminates the need for fuel preparation and reduces the temperature of the processes due to the created aerodynamic conditions for the movement of fuel and air flows, in which the main vortex stream is formed in the lower cylinder due to the tangential air supply, consisting of coke, air, CO ₂ and H ₂ O; gasification of fuel is carried out, providing heat with the endothermic reaction of its decomposition. The main vortex flow continuously rises upward in a spiral with horizontal rotational movements, and as the conical part of the body passes through, its axial component decreases, while the tangential and radial components increase. In this case, the amount of air supplied to the gasification zone is 1.5-2.5 times higher than the amount supplied to the pyrolysis zone, provides a high density of the main vortex, which allows to overcome the gravity of the fuel particles and prevent them from falling. At the same time, secondary vortices arise in the upper cylinder due to the radial air supply by a multi-jet flow through the perforated wall of the housing. In these secondary vortices, the fuel rotates, warms up, its high-speed pyrolysis occurs, in which volatiles are removed from the fuel particles, oxygen diffuses into the internal volume of the particle, interacting with the carbon skeleton and the substance located in the inter-carbon space. Secondary vortices when they meet the main stream give him an additional impulse, maintaining large relative velocities of the gas and solid phases, thereby reducing the effect of gravity on the separation of fuel particles. In this case, inertial unreacted particles return to the pyrolysis zone with the occurrence of their repeated rotation until complete combustion. Fine particles of fuel - ash in an amount of not more than 1% - are removed together with the generated generator gas.

It should be noted that air preheating is possible from 300 to 600 ° С, however, even at a temperature of 300 ° С, solid fuel transformation begins and pyrolysis begins. An increase in this temperature is desirable, but leads to a complication and increase in the cost of the heat exchange system between air and gas and is therefore impractical. To higher temperatures, heating is impossible due to the lack of physical heat in the gas and the imperfection of heat exchange between air and gas. Therefore, heating the air to a temperature of at least 300 ° C is necessary and sufficient for the implementation of the proposed method.

The design of the inventive device for generating generator gas is combined with the proposed method by a single inventive concept and ensures its implementation.

Analysis of the known technical solutions allows us to conclude that the claimed invention is not known from the level of the studied technology, which indicates its compliance with the criterion of "novelty."

The essence of the present invention for specialists does not follow explicitly from the prior art, which allows us to conclude that it meets the criterion of "inventive step".

The possibility of implementing the inventive method for producing generator gas using the proposed device, consisting of affordable, industrially produced materials and components, indicates the compliance of the invention with the criterion of "industrial applicability".

The drawing schematically shows the inventive device for producing generator gas, where the following notation:

1 - metal case;

2 - heat exchange shirt;

3 - dividing wall;

4 - cover;

5 - a hatch for loading fuel;

6 - pipelines;

7 - air flow regulators;

8 - nozzles in the pyrolysis zone;

9 - nozzles in the gasification zone;

10 - through perforation of the housing wall;

11 - pipe;

12 - a cap;

13 - upper and lower parts of the body in the form of a cylinder;

14 - the middle part of the body in the form of a truncated cone;

15 - gas-air heat exchanger.

The proposed device for producing generator gas contains a vertical metal housing 1 made of stainless steel having upper and lower cylindrical parts 13 and a middle part 14 in the form of a truncated cone. Housing 1 has a cover 4 with a hatch for loading fuel 5. Housing 1 is equipped with a heat exchange jacket 2 with a dividing wall 3. Housing 1 is equipped with piping 6 with flow controllers 7, nozzles 8 in the pyrolysis zone and 9 in the gasification zone. Between the nozzles 8 in the pyrolysis zone, the wall of the casing has a perforation 10. Inside the casing 1, a system for extracting the generated generator gas is arranged coaxially with it, consisting of a pipe 11 with a cap 12.

A prototype device for generating generator gas was made in the conditions of a machine-building enterprise in Yekaterinburg and was tested for 3 months under continuous operation.

Example. Generator gas production.

Polydisperse solid fuel (wood processing waste) with a particle size of 3-10 mm and a humidity of 40-50% was loaded into the housing 1 through the hatch 5.

At the same time, air preheated to 300 ° C was tangentially fed. The air in the gasification zone was heated in a heat-exchange jacket 2 by heat exchange with the wall of the housing 1, and in the pyrolysis zone by hot generator gas coming from the pipe 11 into the gas-air heat exchanger 15. The air was supplied to the pyrolysis zone at a speed of 10-12 nm / s tangentially pipelines 6 through nozzles 8 and an additional multi-jet flow directed radially through a perforated wall 10. At the same time, air was supplied into the gasification zone at the same speed and temperature through the nozzles 9 by a tangential flow. The amount of air was set using flow regulators 7, and in the pyrolysis zone it was 20 m ³ / h, and in the gasification zone 40 m ³ / h. The coefficient of excess air is 0.20. From the moment fuel and air entered the building 1, generator gas was obtained with simultaneous pyrolysis and gasification at a temperature of 600 ° C in a single reaction volume. The aerodynamic conditions created inside the housing 1, provided continuous circulation of fuel until it was completely burned and the generator gas was produced, which was removed from the housing 1 through the pipe 11 with a cap 12. A part of the physical heat of the obtained gas was spent on heating the air sent to the pyrolysis zone through the heat exchanger 15 , and the bulk was transported to the consumer. (With an increase in the temperature of the supplied air above 300 ° C, the course of the process of producing generator gas does not change).

The power of the device is 200 kW; Efficiency = 0.9; the calorific value of the generator gas is 8 MJ / m ³ ; gas composition,%: СО 32, H ₂ 25, СН ₄ 3, N ₂ 40; the amount of ash 1%; device weight 150 kg; price 80,000 rub.

As can be seen from the above example, the use of the claimed invention in comparison with the nearest domestic analogue [See Thermotech company prospectus, http://www.yasen.ru/gazgen.htm] and prototype [“Demonstration of the vortex process for biomass gasifiers”] provides the following technical and socially useful advantages:

- increasing the efficiency of the method with obtaining high-calorie gas;

- lowering the temperature of the process, eliminating the use of refractories, increasing the service life of the device;

- lack of special fuel preparation;

- increased environmental safety by reducing by 3-5 times the amount of pollutants when released into the atmosphere;

- technical safety during operation of the device;

- high efficiency;

- lack of need for professional training of staff;

- payback of equipment in the range from 2 months to a year;

- reduction of metal 3-7 times;

- a reduction in the price of the device by 1.5-3 times compared with domestic counterparts and 3-5 times compared with imported products.

Claims (3)

1. A method of producing generator gas by pyrolysis and gasification of solid fuel, including loading fuel, tangential supply of a preheated air stream to the pyrolysis zone with simultaneous suspension processes in a single reaction volume, characterized in that polydisperse fuel with a particle size of not more than 10 mm, to which an air flow is supplied at a speed of 7-15 nm / s, heated to a temperature of at least 300 ° C, and in addition to the pyrolysis zone, air is additionally supplied with a multi-jet stream directed radially, at the same time air is also supplied to the gasification zone by a tangential flow having thermodynamic characteristics identical to the pyrolysis zone, pyrolysis and gasification are carried out at a temperature of 580-600 ° C and an excess air coefficient of 0.15-0.25 with regulation of air flow, which the gasification zone is 1.5-2.5 times higher than the flow rate in the pyrolysis zone, which ensures continuous circulation of fuel until it is completely burned. 2. Device for producing generator gas, comprising a vertical metal casing, provided with a lid with a fuel loading hatch in the upper part, having nozzles for tangential air flow in the pyrolysis zone and a system for extracting produced gas, characterized in that in the pyrolysis zone between the nozzles the casing wall has through perforation to create a multi-jet flow, nozzles for tangential air supply are also installed in the gasification zone, and the system of exhaust gas generation is made in the form of the hull with a cap and is located inside the body coaxially with it. 3. The device according to claim 2, characterized in that the housing in the upper and lower parts has the shape of a cylinder, and in the middle - a truncated cone.