RU2406032C2 - Plasmochemical reactor for processing of solid wastes - Google Patents

Abstract

FIELD: power industry. ^ SUBSTANCE: plasmochemical reactor for processing of solid wastes is made in the form of shaft furnace with loading device, smelting chambers, gas outlet and drain hole. It includes downward in-series located in the well the drying chamber of solid wastes with plasma generators of supply of heated working gas in quantity of 2 to 6, which are equally located along the circumference of plasma generator, gasification chamber of solid chambers with plasma generators for supply of heated working gas in quantity of 2 to 6, which are equally located along the circumference of plasma reactor, zone of formation of glasslike slag compound with branch pipes of plasma generators for supply of heated working gas in quantity of 2 to 6, which are equally located along the circumference of reactor; at that, in drying chamber as working gas there can be used gas of the group including carbon dioxide, air, water vapour, argon, in gasification chamber as the working gas there can be used the gas of the group including water vapour, carbon dioxide, hydrogen, argon, air, and in formation zone of glasslike slag compound as working gas there can be used air or carbon dioxide. ^ EFFECT: increasing efficiency of plasma processing of solid wastes owing to increasing calorific value of pyrogas obtained in reactor. ^ 1 cl, 1 dwg

Description

The invention relates to the protection of the environment, and in particular to methods of processing solid waste.

Known installation for plasma processing of waste (patent RU No. 2143086). The invention relates to a device for thermal disposal of waste by pyrolysis and can be used in the processing of domestic and industrial waste, generation of heat and electric energy. The installation for plasma processing of waste includes a pyrolysis furnace with a plasmatron with an autonomous power supply, the outputs of which are connected to the inputs of a slag granulator, a metal receiver, a pyrogas treatment system, a water treatment line, a heat exchanger, and an energy unit. The water treatment line contains a brackish or seawater intake manifold made with at least two arms, each of which has at least one heat exchanger. The output of the pyrogas cleaning system is connected to the input of the energy block. One sleeve of the intake manifold is located inside the heat exchanger connected to the plasma torch and the power source, inside the slag granulator and the liquid metal receiver, mounted one after the other along this sleeve. The outlet of this sleeve is connected to the inlet of the dispensing manifold. The second sleeve is located inside sequentially installed heat exchangers, which are autonomously connected either to the pyrolysis furnace, or to the pyrogas treatment system, or to the energy block. The output of the second sleeve is connected to the second input of the distribution manifold, the outputs of which are input to the inputs of the distillation desalination and reverse osmosis desalination plants. One of the outputs of the distillation desalination plant is connected to the input of the cooling system of the power source of the plasma torch and to the input of the energy block, and the output of a pair of energy block is connected to the corresponding inputs of the pyrolysis furnace and distillation desalination plant. The disadvantages of this device are the low efficiency of waste processing and high energy consumption during operation of the device.

A known plasma-chemical reactor furnace (Utility Model RU No. 30931), containing the vaulted and hearth parts, plasmatrons, a melting chamber with drain channels, where the vaulted and hearth parts of the furnace are detachable with lock joints and fixing elements and the hearth of the furnace is mounted on a sliding carriage containing supporting platform and jacks. The disadvantages of the known technical solutions are the selectivity of the use of this device and environmental pollution by the products of the furnace.

Known furnace plasmachemical reactor (prototype). Utility model RU No. 44165)) containing detachable vault and hearth parts, a melt crucible and drain channels, where under the crucible in the hearth of the furnace and around the drain channels there are heaters with a control circuit associated with a control circuit with plasmatrons. Moreover, the heaters are made tubular, and their conclusions are connected to a source of external heat. In addition, the heaters are made by induction, and their conclusions are connected to a high-frequency generator. The furnace is intended for plasma processing of solid waste (domestic and industrial) with the production of combustible pyrogas and glass-like slag compound. The disadvantages of the known technical solutions are low efficiency of the device and environmental pollution by the products of the furnace.

For a reactor made in the form of a shaft furnace with one, two or more melting chambers at the bottom of the reactor, solid waste loaded into the upper part of the reactor (shaft furnace) through a loading device and filling the reactor (furnace) is processed under the action of heat to high temperatures (5000-7000 ° C) using plasmatrons of air supplied to the lower part (to the melting chamber) of the reactor (furnace). At the same time, temperature zones are formed along the height of the furnace (mine) with the prevalence of various plasma-chemical processes: in the upper part of the reactor (shaft furnace) - drying of waste at temperatures of 100-250 ° C, in the middle part - gasification of the organic component of the waste at temperatures of 300-600 ° C, in the lower part of the reactor (melting chambers) at temperatures of 1100-1500 ° C - oxidation of the inorganic part of solid waste, melting and synthesis of glass-like slag compound.

This technical solution has the following disadvantages.

1) In the drying zone of solid waste, in addition to drying, sublimation of organic components of waste such as volatile resins is carried out, followed by their deposition at the exit of the plasma chemical reactor on parts of gas ducts having a temperature below the condensation temperature of the resins, which leads to the loss of part of the pyrogas and “tarring” of the plasma -technological complexes, which include a plasma-chemical reactor.

2) In the zone of gasification of organic components from the solid waste composition, the oxygen content in the composition of the working gas (air) supplied to the plasma-chemical reactor (furnace) is small due to its participation in the oxidation reactions of the inorganic part of the solid waste in the lower part of the reactor (in the melting chamber). As a result, a significant part of the organic component of the waste is mainly subjected to thermal decomposition under the influence of air heated by plasmatrons of nitrogen, which also leads to an increase in the proportion of volatile resins in the composition of pyrogas.

3) The use of air as a working gas in the plasma chemical transformations of solid waste leads to the fact that a significant part of the pyrogas (up to 60%) discharged from the plasma chemical reactor is heated nitrogen. The presence of such a high proportion of nitrogen in the composition of the pyrogas leads to a significant decrease in the calorific value of the pyrogas and, as a result, to a decrease in the calorific value of the pyrogas with its subsequent use for generating electricity.

4) The supply of air heated by plasmatrons to the surface of the slag in the melting chamber of the reactor, almost perpendicular to its surface, leads to the existence of thermal overvoltages in the area where the melting chamber joins the shaft part of the reactor due to the low thermal conductivity of the glass-like slag compound, its weak mixing and the existence of reflection from surface slag compound flows of high-temperature gas (air).

T.O. the technical effect to which this invention is directed is to increase the efficiency of plasma processing of solid waste, expressed as a technical result - increasing the calorific value of the pyrogas obtained in the reactor during the processing of solid waste.

Improving the efficiency of plasma processing of solid waste is ensured by the design of the plasma chemical reactor (plasma furnace), shown in the drawing, which shows:

1. Boot device.

2. The reactor shaft.

3. Drying zone for recyclable solid waste.

Drying chamber.

Plasma generator for supplying heated working gas for drying solid waste.

4. Gasification zone of processed solid waste.

Gasification chamber.

Plasma generator for supplying heated working gas for gasification of solid waste.

5. The formation zone of the glass-like slag compound.

A nozzle (lance) of the input of the heated working gas to form a glass-like slag compound.

Plasma generator for supplying heated working gas to form a glass-like slag compound.

6. The drain hole.

7. The gas outlet of the pyrogas.

Plasma-chemical reactor for processing solid waste is as follows.

Solid waste is loaded into the reactor through the charging device 1. The waste loaded into the reactor fills the shaft 2 to the outlet pipe of the loading device 1.

Working chamber 3.1 is fed into the waste drying chamber 3.1 through plasma generators (plasmatrons) 3.2. Carbon dioxide (CO ₂ ) heated to high temperatures (5000-7000 ° C at the outlet of the plasma torch channel) can be used as a working gas. In a plasma generator (plasmatron) 3.2, in an arc discharge, carbon dioxide decomposes: СО ₂ → СО + О. The moisture contained in solid waste interacts with the decomposition products of carbon dioxide in the drying zone of processed waste 3 at temperatures of 100-250 ° C with the formation of hydrogen: H ₂ O + CO → H ₂ + CO ₂ . Carbon-containing waste interacts in the drying zone of the processed waste 3 with the decomposition products of carbon dioxide and form carbon monoxide: С + О → СО. The gaseous reaction products enter the gas outlet 7. The amount of working gas supplied per unit time (working gas flow rate) and its temperature may vary depending on the humidity of the processed solid waste. The required flow rate of the working gas (CO ₂ ) and its temperature are determined by the maximum yield of the main reaction products - carbon monoxide and hydrogen. The content of the reaction products is determined in the drying zone of the processed waste 3. Plasma-chemical processes in the drying zone of solid waste 3 can include not only the drying processes of the waste, but also other plasma processing processes, including plasma pyrolysis and gasification. In this case, in plasma generators 3.2 located in the solid waste drying chamber 3.1, other working gases can also be used as working gases: water (water vapor), air, argon. It is also possible to use combinations of plasma generators 3.2 operating on various working gases and located in the chamber for drying solid waste 3.1.

Working gas heated to high temperatures (5000-7000 ° C - at the outlet of the plasma torch channel) is fed into gasification chamber 4.1 through plasma generators (plasmatrons) 4.2. As the working gas, water vapor heated to the indicated temperatures can be used, i.e. water is supplied to the plasma generators as a working fluid. In the plasma generator (plasmatron) 4.2 in an arc discharge, water decomposes: H ₂ O → H + OH → H + H + O. During the interaction of organic components of solid waste in gasification zone 4 at temperatures of 300-600 ° C with heated working gas (and its decomposition products), a number of processes occur - decomposition of the organic components of the waste, formation of carbon monoxide, and saturation of free carbon bonds with hydrogen. The gaseous reaction products through the drying zone 3 enter the gas outlet 7. The amount of working gas (water vapor) supplied to the gasification chamber 4.1 per unit time (flow rate) by plasma generators 4.2, and its temperature may vary depending on the proportion of the organic component in the composition of solid waste . The required flow rate of the working gas (water vapor) and its temperature are determined on the basis of two main criteria: minimizing the yield of resins as reaction products and the highest binding of water vapor in the reactions. The first is determined by the deposition of resins in the flue 7 per unit time, the second - by minimizing moisture content outside the gasification zone 4 (between the drying zones 3 and gasification 4). In the zone of gasification of solid waste 4 can be used as working gases in plasma generators 4.2 located in the chamber for gasification of solid waste 4.1, and other working gases: carbon dioxide, hydrogen, air, argon. It is also possible to use combinations of plasma generators 4.2 operating on various working gases and located in the chamber for gasification of solid waste 4.1.

Working gas is supplied to the formation zone of the glass-like slag compound 5 through nozzles 5.1 using plasma generators (plasmatrons) 5.2. The working gas is heated to high temperatures (5000-7000 ° C at the outlet of the plasma torch channel). Air can be used as a working gas, including air enriched with oxygen. The inorganic component from the composition of solid waste, when interacting with oxygen, heated by plasma generators 5.2 air at temperatures of 1100-1500 ° C forms the oxides of metals and nonmetals, a mixture of which forms a glass-like slag compound. The amount of working gas (air) supplied to the formation zone of the glass-like slag compound 5 per unit time (flow rate), and its temperature can vary depending on the proportion of inorganic component in the composition of solid waste. Carbon dioxide (CO ₂ ) can also be used as a working gas in plasma generators 5.2. A combination of working gases (air and carbon dioxide) is also possible when different working gases are used on various plasmatrons installed in nozzles 5.1.

The temperature of the working gas is determined based on the amount of heat introduced by the heated working gas flow and necessary to maintain the glass-like slag compound in the molten state at temperatures of 1200-1300 ° C. The amount of working gas (air) supplied to the formation zone of a glass-like slag compound is determined on the basis of the need for complete oxidation of the inorganic component of solid waste and the production of a chemically neutral non-water-insoluble (practically) glass-like slag compound. The preparation of a neutral and water-insoluble glass-like slag compound can be controlled based on chemical analysis of slag samples.

To improve the mixing processes of the molten slag compound, heated air can be supplied under the layer of molten slag, which will provide the necessary bubbling, better heat transfer from the heated air to the slag and its more complete oxidation. This is achieved by maintaining the required level of slag compound.

The accumulated slag compound is removed through the drain hole (or drain device) 6.

The process of processing solid waste in a plasma chemical reactor is carried out continuously. The waste loaded by the loading device 1 of the reactor shaft 2 passes successively all temperature zones, descending from top to bottom. As the temperature zones pass: in the drying zone of the processed solid waste 3, the humidity of the waste decreases and the volume of the solid component decreases slightly, the gaseous products of processing are discharged from the reactor through the gas outlet 7; in the gasification zone of the processed solid waste 4, the organic component of the solid waste is processed and the volume of the solid component of the waste is further reduced, the gaseous products of processing are discharged to the gas outlet 7; the remaining inorganic solid waste component has a volume 15-20 times smaller than the volume of solid waste loaded, is oxidized to a glass-like slag compound in the formation zone of the glass-like slag compound 5, the processing product is a glass-like slag compound is removed as it accumulates (in batches or continuously) through drain hole 6. As the waste level is processed and lowered in the reactor shaft 2, the reactor is loaded with solid waste through the charging device 1. Gaseous moves from the reactor via the gas duct and the top of the reactor shaft is maintained vacuum required in order to avoid ingress of gaseous reaction products into the ambient atmosphere.

T.O. Thanks to the efficient design of the plasma chemical reactor, the efficiency of the plasma processing of solid waste is increased by increasing the calorific value of the pyrogas obtained in the reactor during the processing of solid waste.

Claims (1)

Plasma-chemical reactor for processing solid waste, made in the form of a shaft furnace with a loading device, smelting chambers, a gas outlet and a drain hole, including a solid waste drying chamber with plasma generators for supplying heated working gas in an amount from 2 to 6, arranged sequentially in the shaft from top to bottom, uniformly located around the circumference of the plasma reactor, a chamber for gasification of solid waste with plasma generators for supplying heated working gas in an amount of 2 to 6, uniformly distributed laid around the circumference of the plasma reactor, the formation zone of the glass-like slag compound with the nozzles of the plasma generators for the supply of heated working gas in an amount of 2 to 6, evenly spaced around the circumference of the reactor, and in the drying chamber, gas from the group comprising carbon dioxide can be used as working gas , air, water vapor, argon, in the gasification chamber, gas from the group including water vapor, carbon dioxide, hydrogen, argon, air, in the formation zone can be used as a working gas By using a glass-like slag compound, air or carbon dioxide can be used as the working gas.