RU2780782C1 - Method for processing solid household waste - Google Patents

Abstract

FIELD: waste treatment.

SUBSTANCE: invention relates to methods of thermal processing of solid organic household waste. The method for processing solid household waste includes the stages of magnetic separation and crushing of waste up to 5-10 mm, drying with recirculating flue gases, pyrolysis of solid household waste with separation of pyrolysis gases into combustible gases, pyrolysis oil and water, mixing of coal with pyrolysis oil in a ratio of 20:1 and extrusion, repeated pyrolysis of granules, cooling of granular coal, capping ready-made coal granules. Conductive pyrolysis is carried out in two stages: at the first stage, the pyrolysis chamber is heated by flue gases to a temperature of 500-550°C, and at the second to 800-900°C. Coal is cooled to a temperature of 50-60°C by separated water irrigation.

EFFECT: invention provides for the creation of an energy-saving method for producing pyrolysis oil and activated carbon granules, which, depending on the composition of the processed raw materials, can be used as a high-calorie fuel, absorbent or biochar for soil enrichment.

1 cl, 2 dwg, 1 tbl

Description

The invention relates to methods for the thermal processing of solid organic household waste to produce liquid pyrolysis fuel, can be used in public utilities, in the chemical, petrochemical and other industries, for example, for processing waste paper, rubber, textiles and other materials.

Known solution RU 2734311 C1 "Method of processing municipal solid waste", IPC F23G 5/027, C10B 47/00, including the loading of municipal solid waste through the loading flexible conveyor into the inner tubular pyrolysis chamber, where flue gases heat the air in the space between the outer tubular chamber and the inner tubular pyrolysis chamber are affected by the temperature of the air passing through the outer tubular chamber and the fins of the inner tubular pyrolysis chamber to the exhaust pipe, on the inner tubular pyrolysis chamber with the possibility of heating it and subsequent decomposition of household waste into pyrolysis gas, by means of their mixing by horizontal and vertical blades of the knife, with the subsequent rise of the pyrolysis gas to the upper part of the inner tubular pyrolysis chamber, and its further flow through the pyrolysis gases pipe into the pyrolysis tube, and then into the condenser, where, due to the cooling tubes, the pyrolysis gas is separated into water, pyrolysis oil and non-condensable gas that leaves the condenser through the gas pipe is fed into the cooling jacket of the burner combustion chamber, where it enters the burner combustion chamber through the holes, where heated air is supplied from the fan, through the duct and nozzle, for the exothermic reaction, and the resulting solid the residue in the form of carbon is fed into the lower part of the inner tubular pyrolysis chamber, from where the solid residue is discharged into the discharge conveyor.

The disadvantage of the prototype is the unreliability of the installation: the knives installed in the pyrolysis chamber at high temperature and the presence of metal inclusions quickly fail, and the heat exchange surface of the condenser is quickly clogged with resinous substances of the pyrolysis gas condensate. The short residence time of the flue gases in the jacket of the pyrolysis chamber reduces the efficient use of the energy of exothermic processes. Low quality solid product: low density and low specific heat of combustion per unit volume.

To implement the claimed method for producing activated carbon, a technological scheme of hardware design is presented, see Fig. 1 and drawings of perforated metal plates with S-shaped blades on odd (A) and even (B) plates, see FIG. 2.

The technical problem to which this solution is directed is the development of a method for processing municipal solid waste with increased efficiency, providing for the possibility of obtaining pyrolysis oil and high-quality solid fuel.

The claimed processing method of Fig. 1 consists of: a waste preparation zone, including a magnetic separator (1) for removing metal inclusions and a disk grinder (2), a convective drying zone (3), a zone for the first stage of pyrolysis (4), a screw extruder ( 5), zones of the second stage of pyrolysis (6), gasification zones (7), capping zones (8), pyrolysis gases condensation zones (9), pyrolysis oil accumulation zones (10), rotary feeders (11a - 11d), absorber (12 ), a furnace (13), a screw conveyor (14) with a jacket (20c), a buffer tank (15), heat exchangers (16a - 16b), gas blowers (17a - 17b). The pyrolyzer of the first stage includes perforated metal plates (18) with discharge holes (22a, 22b), S-shaped blades (19) mounted on a shaft (21), a jacket with spiral guides (20a).

The pyrolyzer of the second stage has a jacket with spiral guides (20b).

The process of processing municipal solid waste, see Fig. one.

Solid household waste is continuously passed through a magnetic separator (1) to remove metal inclusions and crushed in a disc grinder (2) to obtain fine particles of 5-10 mm in size. The crushed waste is fed by a rotary feeder (11a) to the drying chamber (3), where the waste is subjected to convective drying with flue gases from the jacket (20a) of the first pyrolysis chamber (4).

At the inlet of the convective dryer (3), the temperature is maintained by recirculation of the waste coolant using a gas blower (17a) and temperature and humidity sensors. Dried municipal solid waste is sent by a rotary feeder (11b) and a screw conveyor (14) to the first pyrolysis chamber (4) with perforated metal plates (18) installed in it and a mixing device in the form of a shaft (21), on which horizontal blades S- are fixed. figurative form (19). Odd plates have discharge holes (22a) in the center, and on even plates, discharge holes (22b) are located on the periphery. Solid domestic waste inside the first pyrolysis chamber (4), heated to a temperature of 500-550°C, is moved along the heated surfaces of the plates (18) to the discharge openings alternately from the periphery to the center and vice versa by rotating the S-shaped blades (19). The resulting pyrolysis gases pass through the perforation of the plates and convectively heat the raw material. After passing the first stage of pyrolysis, the resulting coal enters the screw extruder (5), where the coal is mixed with pyrolysis oil in a ratio of 20:1 and extruded. The obtained granules are fed to the second stage of conductive pyrolysis at a temperature of 800-900°C in a shaft-type apparatus. Then the granulated coal is fed by a rotary feeder (11c) into the gasification chamber (7) and cooled to a temperature of 50-60°C by irrigation with water, which is supplied from the buffer tank (15). Cooled activated granulated carbon with dimensions of 5-10 mm is fed by a rotary feeder (11g) to a capping (8). The pyrolysis gases from the first and second pyrolysis stages are combined and ejected with chilled water separated from the pyrolysis liquid. The pyrolysis liquid, accumulating in the condenser tank (9), is separated into water and pyrolysis oil. Pyrolysis oil is withdrawn into a collector (10) and partially fed into a screw extruder (5). The separated water from the condenser tank (9) is cooled and fed to the ejection of pyrolysis gases and partially fed into the buffer tank (15). The gasification products from the gasification chamber (7) and non-condensed gases from the condenser (9) together with the heated air supplied by the gas blower (17b) are burned in the furnace (13) and flue gases are obtained. Flue gases from the furnace (13) are sequentially passed through: a heat exchanger (16b), for air heating; shirts (20a, 20b) of the second and first pyrolysis chambers (4,6), shirt (20c) of the screw conveyor (14) and fed to the convective drying of the processed raw materials. Exhaust flue gases from the drying chamber (3) are cleaned in the absorber (12) and released into the atmosphere. The absorbate from the absorber (12) is sent for recirculation and partially into the buffer tank (15).

The present invention illustrates the following specific examples.

Example 1. The method of processing municipal solid waste is carried out as follows: waste paper, rubber, textiles with a moisture content of 30% are passed through a magnetic separator and crushed in a disk grinder to a size of 5 mm. Convective drying of crushed raw materials is carried out in a drying chamber at a temperature of the drying process of 250°C. The materials from the drying chamber are sent by a screw feeder to the first stage of conductive pyrolysis, which is carried out at a temperature of 500°C. The resulting coal is sent to a screw extruder, mixed with pyrolysis oil in a coal-to-oil ratio of 20:1 and extruded. The resulting granules are sent to the second stage of conductive pyrolysis at a temperature of 800°C. The cooling of the coal granules is carried out by irrigation with water to a temperature of 50°C. After cooling, the activated granules and pyrolysis oil are subjected to analytical studies.

Example 2. The method of processing municipal solid waste is carried out as follows: waste paper, rubber, textiles with a moisture content of 60% are passed through a magnetic separator and crushed in a disk grinder to a size of 7 mm. Convective drying of crushed raw materials is carried out in a drying chamber at a temperature of the drying process of 300°C. The materials from the drying chamber are sent by a screw feeder to the first stage of conductive pyrolysis, which is carried out at a temperature of 525°C. The resulting coal is sent to a screw extruder, mixed with pyrolysis oil in a coal-to-oil ratio of 20:1 and extruded. The resulting granules are sent to the second stage of conductive pyrolysis at a temperature of 850°C. The cooling of the coal granules is carried out by irrigation with water to a temperature of 55°C. Cooled activated granules and pyrolysis oil are subjected to analytical studies.

Example 3. The method of processing municipal solid waste is carried out as follows: waste paper, rubber, textiles with a moisture content of 90% are passed through a magnetic separator and crushed in a disk grinder to a size of 10 mm. Convective drying of crushed raw materials is carried out in a drying chamber at a temperature of the drying process of 350°C. The materials from the drying chamber are sent by a screw feeder to the first stage of conductive pyrolysis, which is carried out at a temperature of 550°C. The resulting coal is sent to a screw extruder, mixed with pyrolysis oil in a coal-to-oil ratio of 20:1 and extruded. The resulting granules are sent to the second stage of conductive pyrolysis at a temperature of 900°C. The cooling of the coal granules is carried out by irrigation with water to a temperature of 60°C. Finished products: activated granules and pyrolysis oil are subjected to analytical studies.

The study of the properties of coal granules and pyrolysis oil obtained by the claimed method was carried out at the Center for the Collective Use of Scientific Equipment for the Production and Study of Metal Nanoparticles, Metal Oxides and Polymers "Nanotechnologies and Nanomaterials".

The adsorption activity of coal granules for iodine, obtained by the claimed method, was determined in accordance with GOST 6217-74.

The density of activated granules obtained by the claimed method was determined in accordance with GOST 10742-71.

The specific heat of combustion of activated granules obtained by the claimed method was determined in accordance with GOST 147-2013.

The specific heat of combustion of pyrolysis oils obtained by the claimed method was determined in accordance with GOST 21261-91.

Data on indicators of activated granules and pyrolysis oils are given in Table 1.

Table 1

experience number one 2 3 Particle size, mm 5 7 ten Temperature of the drying process, °С 250 300 350 Humidity of raw materials, % thirty 60 90 Temperature of the first stage of pyrolysis, °С 500 525 550 Temperature of the second stage of pyrolysis, °C 800 850 900 Temperature of finished coal granules, °C fifty 55 60 Adsorption activity for iodine, % 64 62 60

Density of activated granules,

1400 1550 1600 Oud. calorific value of activated granules, MJ/kg 35 31 27 Oud. heat of combustion of pyrolysis oil, MJ/kg 43 41 39

An analysis of the results of analytical studies shows that the proposed method makes it possible to obtain coal granules with a high density and calorific value, close in properties to anthracite, and pyrolysis oil with a high calorific value suitable as a liquid fuel.

S-shaped blades in the pyrolysis chamber, due to preliminary cleaning of raw materials from metal inclusions, practically do not wear out, and, when the pyrolysis gas is condensed by ejection of cooled separated water, resinous substances do not settle on the heat exchange surface of the condenser. These factors significantly increase the reliability of hardware design in the implementation of the proposed method.

The use of flue gas energy at all endothermic stages of the thermal processing of organic waste significantly increases the efficiency of using the energy of exothermic processes during the combustion of combustible gases.

Claims (1)

A method for processing solid domestic waste, including loading solid domestic waste with a screw conveyor into a pyrolysis chamber equipped with a jacket, where conductive pyrolysis is carried out with mixing of solid domestic waste by rotating a shaft associated with horizontal blades, unloading hot coal obtained during pyrolysis is carried out by a screw extruder, pyrolysis gases obtained during pyrolysis are sent to the condenser, where they are cooled and pyrolysis liquid is condensed from them, which, accumulating in the condenser tank, is separated into water and pyrolysis oil, and uncondensed combustible gases from the condenser, together with heated air, are fed into the furnace, the resulting furnace gases are fed into the jacket of the pyrolysis chamber, characterized in that solid household waste is cleaned in a magnetic separator before being loaded by a screw conveyor into the pyrolysis chamber, crushed to a size of 5-10 mm and sent by a rotary feeder for convective drying with flue gases from the jacket of the pyrolysis chamber ry, pyrolysis is carried out in two stages: at the first stage, the pyrolysis chamber is heated to a temperature of 500-550 ° C with flue gases passing along a spiral guide in the jacket of the pyrolysis chamber, solid domestic waste inside the pyrolysis chamber is moved along the heated perforated surfaces of metal plates to the discharge openings in turn from the periphery to the center in odd trays and from the center to the periphery in even trays by rotating the S-shaped blades, the resulting hot coal is mixed with pyrolysis oil in a coal-to-oil ratio of 20:1 and granulated in a screw extruder, the resulting granules are fed to the second stage of conductive pyrolysis at a temperature of 800-900 ° C in a mine-type apparatus, which is heated by flue gases passing along the spiral guide of the jacket of the second pyrolysis chamber, obtained by burning combustible gases in the furnace, granulated coal is sent by a rotary feeder to the gasification chamber, where it is cooled to a temperature of 50-60 ° With water irrigation, activated these granules are sent for capping, pyrolysis gases from the first and second stages of pyrolysis are combined and ejected with cooled separated condenser water, pyrolysis oil is taken to a collector and partially fed for mixing, separated water from the condenser tank is partially fed into a buffer tank, combustible gases are obtained by mixing gasification products from the gasification chamber and non-condensed gases from the condenser, the exhaust flue gases from the drying chamber are cleaned in the absorber and released into the atmosphere, part of the absorbate from the absorber is sent to the buffer tank, water for irrigation is supplied from the buffer tank.

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