RU2721695C1 - Method of processing organic material to produce synthetic fuel gas in a high-temperature ablation pyrolisis of gravitational type - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: invention relates to processing of organic substances as mono-composition, and raw materials of complex composition, namely to method of high-temperature ablation pyrolysis. Method of organic raw materials processing includes stages, at which raw material is ground and dried, after which raw material is supplied into hopper-cyclone with lower conical part, where air is separated from raw material, from the lower part of the cyclone bunker, the solid part of the raw material enters the horizontal screw, from wherefrom the raw material is supplied to the lower part of the vertical spiral auger, after which the raw material is supplied to the pyrolysis reactor raw material feed chamber. Reactor has elongated body of vertical arrangement with inclination relative to vertical, divided by wavy plate into two isolated from each other heating zone and pyrolysis zone. Heating zone is flow chamber of flue gases coming from burner arranged in upper part of reactor. Pyrolysis zone is a pyrolysis chamber into which raw material is fed, which is subjected to pyrolysis under heating from the heating zone of the separating plate and guide ribs arranged on the inner surface of the pyrolysis zone. Smoke gases, passing along the whole reactor through the heating zone, are removed through the smoke exhauster located in the lower part of the reactor, and the solid residue, which is pyrolysis coke, is supplied through the outlet in the lower conical part of the reactor to the horizontal coke discharge auger, from where it comes from below into vertical auger, is run to its upper part and is transmitted to tight accumulating hopper of coke. Produced gas in the pyrolysis chamber by means of the gas vortex compressor at the end of the process filtration line is supplied to the cooling and separation apparatuses to obtain syngas which, after cleaning, is supplied to the consumer, and excess is burnt in the emergency flare.

EFFECT: invention allows uniform distribution and heating of raw material by natural (gravitational) method, intended for processing, and obtaining high-quality carbon product with maximum removal of volatile compounds, subject to further activation and production of activated carbon.

1 cl, 5 dwg

Description

The invention relates to the field of processing of organic substances as a mono-composition, and raw materials of complex composition, and in particular to a method of high-temperature ablative pyrolysis.

The high-temperature ablative pyrolysis unit is a system of temperature destruction of a solid substance, separation and purification of pyrolysis products for use. The main decomposition product of a solid is syngas (a mixture of various hydrocarbons and other gases), as well as carbon material. All processes occurring in the installation are optimized for maximum syngas production and production of high-quality carbon residue - pyrolysis coke. Syngas can be used as fuel for generating electricity in gas reciprocating plants or gas turbines, thermal energy in hot water or steam boilers, or as gas-engine fuel after compression. Carbon material - as technical raw material - is used as fuel in devices equipped with solid fuel burners, in the production of activated carbon during its processing in an activation furnace, in the production of building materials, or as solid fuel after bracketing.

The following solutions are known in the art.

A known method of processing solid domestic and industrial waste to produce synthesis gas (RU 2475677 C1, published 02.20.2013), characterized in that the crushed waste in a mixture with CO ₂ and H ₂ O pumped through a gasifier, the resulting gaseous products together with water vapor subjected to hardening in a water-cooled quenching device, additionally cooled to a temperature of 40-50 ° C, then taken by an exhauster and pumped through dust, acid gas, sulfur compounds, resins and organic compounds. The purified gas is divided into two streams, one of which is sent as fuel to the burner, and the second stream is passed through a device for stabilizing the ratio of hydrogen to carbon monoxide to produce synthesis gas of the required composition. Carbon dioxide is emitted from the flue gas in the adsorber and sent to the gasifier inlet. Part of the synthesis gas purified from impurities is used as fuel gas on a flameless type burner.

A known method for producing synthesis gas by pyrolysis of biomass (patent RU 2346026 C2, published 02.10.2009), characterized in that the method is carried out with continuous simultaneous operation of the screw system of three chambers: drying, pyrolysis and separation, in which the biomass intended for pyrolysis is first sent to the feed hopper, then the biomass is pushed through the drying zone, the dried feed is collected in the dry feed hopper, from where part of it is fed with the screw to produce flue gases for heating the screw pyrolyzer, the rest of the dried feed is fed through the screw into the pyrolysis chamber and transported to for a period of time from 2 to 7 minutes through a heated pyrolysis screw space, and high-calorie gas released during pyrolysis is collected in a gas collector, from where it is sent to the consumer, while the solid carbon residue is used in the combustion chamber with the disposal of harmful liquid and solid impurities in the form of resins and tar and the semi-coke is collected in the gas and semi-coke receiving chamber and shipped to the consumer by means of a water-cooled screw.

Also known is a method for waste-free processing of carbon-containing solids, such as wood waste, characterized in that the waste is dried at a temperature of not more than 160 ° C to a moisture content of not more than 3%, while the resulting air-vapor mixture is cleaned and removed, the dried wood waste is subjected to subsequent rapid pyrolysis in a reactor without oxygen at a temperature of 520-830 ° C for no more than 5 s, and the pyrolysis gas formed is sent through a heat exchanger to a condensation system for separation into liquid fuel and synthesis gas, while the heat exchanger serves to transfer part of the thermal energy of the pyrolysis gas for the drying process (patent RU 2451880 C2, published on 05.27.2012).

This processing method does not provide complete purification of pyrolysis gases. Moreover, control of such parameters as gasifier temperature, gas temperature and pyrolysis products is extremely difficult. This directly affects the quality of the syngas and makes the continuous operation of the installation impossible.

Also known is a method of processing organic raw materials known from patent RU 2441053 C2 (published on January 27, 2012). Raw materials containing an organic component are poured into a storage bin. The press auger captures it and advances to the conical part of the furnace body. Holes are located on the cone through which water is squeezed into the drain. The extracted raw material enters the heated section of the heat chamber, where the casing is heated to 200 degrees, and the raw material is prepared for pyrolysis (drying, mixing, granulation), then the raw material enters the cutter, located at an angle to the direction of movement of the raw material. The auger mechanism located above promotes the raw materials along the furnace body, which has a temperature of up to 450 degrees Celsius. At the end of this screw mechanism is also a cutter for creating cork from raw materials and slag. In this case there are holes in the upper part of the case, connected to pipes to remove pyrolysis gas, which is partially used for the operation of burners in a warm chamber. If it is necessary to obtain high-quality pyrolysis fuel, a third screw mechanism is located above the second screw mechanism, which selects second raw materials from the cork for processing at a temperature of up to 800 degrees Celsius. At the end of the screw, a cutter for creating a plug from the slag is also located, which excludes the release of synthesis gas outside the pyrolysis gas exhaust pipes. As slag accumulates, it is squeezed out into a special container for disposal.

The installation used in the method is designed to obtain a liquid fraction of pyrolysis, the use of which is difficult. The horizontal position of the furnace and the forced movement of raw materials can lead to contamination and jamming of the feed device.

The closest analogue to the patented solution is a method of processing organic raw materials (patent RU 2688568 C1, published May 21, 2019), which includes stages in which the raw materials are ground by means of a drying-grinding unit, the raw materials are supplied to a gasifier, which is a cylinder with spiral grooves inside and made of stainless nickel-containing heat-resistant steel, the walls of which are initially heated by an external electric inductor to a temperature of 750 ° C, while the raw material enters a rotating conical disk-sprinkler, from which it is scattered along the walls, and falls down along spiral grooves, during which it decomposes into combined-cycle gas fraction and pyrolysis coke. The gas-vapor mixture from the gasifier through two nozzles enters high-temperature cyclone filters, where the main part of the pyrolysis coke particles carried away with gas is separated and cooled in gas-air heat exchangers to 250 ° С, after which the gas mixture is fed to a distillation column (scrubber), where the mixture It is separated into a liquid fraction, which is discharged from the column into a storage tank for pyrolysis liquid, and a gas fraction, which is cooled in a scrubber to a temperature of 50 ° C and transferred to an adsorption filter, after which the gas enters a duplex fine gas filter with a mesh size of 5 μm and then to the vortex compressor, increasing the gas pressure to 25-70 kPa and heating gas to 80-120 ° С, after which the gas is fed to the cooling system with a separator, where the gas temperature is lowered and maintained at 65-75 ° С, and high hydrocarbon vapors are condensed, which are discharged into a container with a pyrolysis liquid, and the gas fraction is fed to the input of the receiving equipment Dvd for further use as an energy carrier.

The disadvantage of the prototype is the high cost of manufacturing components, the presence of rotating parts in the hot zone and a complex sealing system, as well as the need for significant electrical capacities for starting (heating by induction) reactor and deep grinding of raw materials.

The technical problem is the retention of raw materials in the high-temperature heating zone for such a time that is sufficient to completely remove volatile compounds from the raw material (5-10 seconds, depending on temperature).

The technical result of the patented method consists in the uniform distribution and heating of raw materials in a natural (gravitational) way, intended for processing and obtaining a high-quality carbon product with maximum removal of volatile compounds, which is subject to further activation and production of activated carbon.

The claimed technical result is achieved due to the implementation of a method for processing organic raw materials, which includes stages in which the raw materials are crushed and dried, after which the raw materials are fed to the cyclone bunker with a lower conical part, where the air is separated from the raw material from the bottom of the cyclone bunker the raw material enters the horizontal screw, from where the raw material then enters the lower part of the vertical spiral screw, after which the raw material enters the feed chamber of the pyrolysis reactor having an elongated vertical housing with an inclination relative to the vertical, divided by a wave-like plate into two heating zones isolated from each other and a pyrolysis zone, one of which is a flow chamber of flue gases coming from a burner located in the upper part of the reactor, the other is a pyrolysis chamber, into which raw materials enter, subjected to pyrolysis under the influence of heating from the heating zone of the separation plate and direct of fins located on the inner surface of the pyrolysis zone, while the flue gases passing along the entire reactor through the heating zone are removed through a smoke exhauster located in the lower part of the reactor, and the solid residue, which is pyrolysis coke, enters through the outlet in the lower conical part of the reactor the horizontal auger of the coke outlet, from where it enters from below into the vertical auger, is driven to its upper part and transferred to a sealed coke storage hopper, the gas obtained in the pyrolysis chamber with the help of a gas vortex compressor at the end of the filtration processing line is fed to cooling devices and separation to obtain syngas, which after treatment is supplied to the consumer, and the excess is burned in an emergency flare.

The vertical arrangement of the pyrolysis reactor provides a natural (with the help of gravitational forces) flow of the processed substance, and the given tilt of the chamber relative to the vertical and the wavy surface of the separation plate, provides the optimal residence time of the substance in the high temperature zone, and also creates the conditions for direct contact of the processed substance with heated surfaces. Due to the supply of raw materials to the distribution device using a vertical screw, densely filled with raw materials in the working process, tightness conditions of the pyrolysis chamber are created on the supply side of the raw material at the required gas pressure in the chamber. The horizontal and vertical continuously filled discharge augers guarantee the necessary tightness of the reactor from the discharge side of the carbon residue.

Next, the solution is illustrated by reference to the figures, which show the following.

FIG. 1 is a flow diagram of a plant for high-temperature ablation pyrolysis of the gravitational type.

FIG. 2 is a general view of a pyrolysis reactor.

FIG. 3 is a view A from FIG. 2.

FIG. 4 is a view B of FIG. 3.

FIG. 5 is a view BB of FIG. 2

Raw materials can be any organic compounds of both mono-composition and raw materials of complex composition, with a moisture content of not more than 60% and a fraction size of 5-25 mm. At higher values of humidity and size, it is necessary to use additional technical equipment for the use of raw materials in the process.

The technological process begins with the supply of raw materials. The raw material is fed by a closed screw conveyor to the inlet of the crushing device 1, in which the raw material is ground to a fraction of 1-3 mm. Further, the raw material enters the dryer through the conveyor, where the moisture content of the feed decreases to 2-5%, while hot air 30 from the pyrolysis reactor is used as the drying agent for the dryer. In the case of high humidity of the feedstock, an external heat generator can be used as part of the drying apparatus, operating both on products obtained at the outlet of the described plant (pyrolysis gas, pyrolysis coke, pyrolysis liquid) and on the feedstock.

The prepared raw materials are transferred to the cyclone bunker 4 by a closed screw conveyor. The transportation line of crushed and dried raw materials is equipped with an exhaust fan 3. In order to avoid increasing humidity, the hopper is tight. The hopper is necessary to constantly maintain the guaranteed volume of raw materials and the separation of the solid component of the raw material from the air, which is removed through the duct 5. In the case of stopping the supply of raw materials, servicing conveyors, drying and crushing machines, the hopper allows you to work continuously. The volume of the hopper is determined individually and is usually at least 20 m ³ (to ensure a 5-hour supply of raw materials).

The solid component of the raw material descends under the action of gravity into the conical lower part 6 of the cyclone hopper 4 and enters the horizontal screw 7 at the inlet, which feeds the raw materials to the lower part of the vertical spiral screw 8, from where it is fed to the feed chamber 12 of the pyrolysis reactor 9. Supply of raw materials to the loading chamber with the help of a vertical screw, in the working process tightly filled with raw materials, creates the conditions for the tightness of the pyrolysis chamber from the feed side at the required pressure of 10 kPa of gas in the chamber.

The design of the pyrolysis reactor 9 has an elongated body of rectangular cross section with a conical lower 17 and upper part 12. The case is made of stainless steel and is located vertically with a slope relative to the vertical at an angle of 18-22 °. The reactor is divided by a wave-like plate 31 into two chambers isolated from each other: a heating zone 13 and a pyrolysis zone 11.

The heating zone 13 is a flow chamber of high temperature flue gases generated by burning solid particulate or gaseous fuel 16 in a burner 14 located in the upper part of the reactor with air access 15 to maintain combustion. The flue gases from the burner are used to heat the separation plate 31, as well as the guide ribs 32 of the pyrolysis zone 11. Passing flue gases along the entire reactor, they are removed into the atmosphere by means of a smoke exhauster 21. The heating temperature of 730-1000 ° C is maintained in a predetermined range by adjusting the fuel supply to burner. The temperature regime is maintained using a solid fuel burner; the prepared raw material (dried and, if necessary, crushed) is the same raw material used for processing and / or the carbon material obtained after the pyrolysis process of the proposed installation.

The second zone of the reactor 9 is a pyrolysis zone 11, heated from below by flue gases. The vertical arrangement of the reactor provides a natural (using gravitational forces) flow of the processed substance. The specified camera tilt of 18-22 ° relative to the vertical is necessary to ensure the optimal residence time of the substance in the high temperature zone for the complete reaction of the decomposition of the feedstock into the vapor-gas fraction and the solid residue — pyrolysis coke. The decomposition of raw materials is exothermic (proceeds with the release of heat). Also, the inclined arrangement of the reactor creates the conditions for direct contact of the processed substance with heated surfaces.

Uniform distribution of the substance along the heated plane is carried out by a static device for the distribution of bulk materials located in the upper conical part 12 of the reactor, containing guide ribs 33 oriented along the axis of the reactor and located on the inner surface of the conical part of the pyrolysis zone (Fig. 4). Maintaining uniform flow of raw materials in the reactor is controlled by guide ribs 32 attached directly to the heating plate on the inner surface of the pyrolysis zone (Fig. 5). The range of temperature changes in the reactor is 350-1000 ° C. The temperature (individual for each type of raw material) and pressure (5-25 kPa huts) in the reactor are constant. The lower part of the reactor is made in the form of a cone 17, with a pyrolysis coke level sensor located in it. A pressure sensor is mounted in the reactor vessel.

Constant pressure in the reactor is supported by the coordinated operation of the feed screw and the vortex compressor 27. The carbon substance is discharged from the bottom of the reactor from the outlet located at the bottom 17 by a horizontal cooled sealing screw 18, directly from which the substance flows into the vertical screw 19, in which it flows in a dense stream rises into the bunker of its cooling and temporary storage. The vertical constantly filled screw guarantees the necessary tightness of the reactor from the discharge side of the carbon residue (coke) 20. By means of a transport line, the coke is cooled to 50-70 ° C. The hopper is equipped with an automatic gas removal system. The cooling agent of the screws 18 and 19 is water, cooled by fans in an air-cooling apparatus.

The gas obtained in the pyrolysis zone 11 is removed from it by gas exhaust pipes 34 and collected in a gas manifold 10, from where it enters the cooling and separation apparatus using a gas vortex compressor at the end of the filtration processing line.

Gas preparation stage

Preparation of gas for use consists of several stages. After the reactor, the gas-vapor mixture 22 through the nozzle enters the high-temperature cyclone filter 23, where the main part of the pyrolysis coke particles carried away with the gas is separated. After the cyclone, the vapor-gas mixture is cooled in a shell-and-tube heat exchanger 24 gas-gas from 700 to 250 ° C (cooling air comes from the air intake), then in a liquid heat exchanger 25.

Behind the heat exchangers, the flow enters a vertical condenser 26, where the vapor-gas mixture is separated into a liquid fraction (pyrolysis liquid 35) and gas - synthetic gas (syngas). The liquid fraction 35 is discharged into a pyrolysis liquid tank.

Gas from the condenser 26 is transferred to the vortex compressor 27, which allows to overcome the resistance of the gas treatment system and increases the gas pressure to the required parameters (25-70 kPa gage). The compressor can be manufactured either singly or double (2 or more sequentially installed units), depending on the further purposes of using synthetic gas.

After increasing the pressure, the gas warms up. Behind the compressor, a cooling system with a separator is installed, in which the gas temperature is maintained at a level of 50-60 ° C, and the condensation of high hydrocarbon vapor residues (butanes, hexanes and higher) also occurs. The liquid fraction is discharged into a container with pyrolysis liquid. Syngas can be used as fuel in various systems. The calorific value of the gas is 8-20 MJ / nm ³ depending on the feedstock. Surplus synthesis gas is burned in emergency flare 28.

Claims (1)

A method of processing organic raw materials, including the stages at which the raw material is crushed and dried, after which the raw material is fed to the cyclone hopper with the lower conical part, where the air is separated from the raw material, from the bottom of the cyclone hopper, the solid part of the raw material enters the horizontal auger, from where Further, the raw material enters the lower part of the vertical spiral screw, after which the raw material enters the feed chamber of the pyrolysis reactor having an elongated vertical housing with an inclination relative to the vertical, divided by a wave-like plate into two heating zones and a pyrolysis zone, one of which is a flow chamber of flue gases coming from a burner located in the upper part of the reactor, the other is a pyrolysis chamber, which receives raw materials subjected to pyrolysis under the influence of heating from the heating zone of the separation plate and guide ribs located on the inner surface of the pyrolysis zone, In this case, the flue gases passing through the heating zone along the entire reactor are removed through a smoke exhauster located in the lower part of the reactor, and the solid residue, which is pyrolysis coke, is fed through the outlet in the lower conical part of the reactor to the horizontal auger of the coke outlet, from where it enters from below to a vertical (cooled) auger is driven to its upper part and transferred to a sealed coke storage hopper, the gas obtained in the pyrolysis chamber using a gas vortex compressor at the end of the filtration processing line enters the cooling and separation apparatus to produce syngas, which after purification is supplied to the consumer, and surplus is burned in an emergency flare.

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