RU2480674C1 - Method to burn solid domestic wastes and garbage and device for its realisation - Google Patents

Abstract

FIELD: power engineering.

SUBSTANCE: method to burn solid domestic wastes and garbage consists in forced supply into a boiler furnace, in hot treatment in rotating frame and fuel and air mixture, with electric field acting at them. The electric field is developed by two mutually applying electric fields, at first high voltage of negative polarity is used with (25÷50) kV, oxidising toxic effluent gases with an electronic beam at current force of at least (50÷100) mcA, and then combustion products are exposed to low-frequency alternating electric field in the frequency range of (50÷1000) Hz with voltage of (200÷1000) V, and combustion products are neutralised to produce their solid phase, which is separated.

EFFECT: higher extent of combustion products treatment and reduced energy intensity, higher reliability.

2 cl, 4 dwg

Description

The invention relates to technologies for the incineration of municipal solid waste and can be used in all industries, including railway transport.

A known method of burning waste and debris by fire treatment in a flame of an air-fuel mixture forced to enter the combustion chamber, followed by heat treatment and purification of the exhaust gases, including loading the waste, igniting the waste, and supplying the air-fuel mixture to the combustion zone [US Patent No. 4,306,506, publ. 1981. 12.22, Rotter Franz].

The disadvantage of this method is the incomplete combustion of waste and combustible components due to the low intensity of combustion, and the difficulty of cleaning the exhaust gases.

Known devices for the implementation of the fire treatment of waste and garbage [Bernadiner M.N., Shurygin A.P. “Fire processing and neutralization of industrial waste. - M .: Chemistry, 1990].

The disadvantage of these devices is the low efficiency of combustion, purification and neutralization of toxic components in the exhaust gases.

A known method of burning waste and debris by fire treatment in a flame of an air-fuel mixture, forced feeding of an air-fuel mixture into a combustion zone, a flame and a fuel-air mixture is treated with a strong electric field with an intensity of at least 3 kV / cm, and the electric field is regulated either mechanically by raising or lowering the central electrode above the flame, or electrically from a semiconductor voltage and frequency converter, regulate the electron emission current into the flame x waste by changing the area of the emission needle electrode and the frequency of the electric field fluctuations from the condition of the best quality of environmental cleaning of the exhaust gases, rotate the air-fuel mixture and / or flame in the transverse plane to the flame front mechanically by rotating the movable nozzle, or by the electric (electromagnetic) method by rotating the flame rotating electric (electromagnetic) field, and the frequency of rotation of the flame is chosen from the condition of the best quality environmental cleaning thodyaschih gases [Russian patent RU 2117870, F23G 5/00, publ. 08/20/1998, BI No. 23, author Dudyshev V.D. "Method of burning waste and garbage and device for its implementation"].

The disadvantage of this method is the low environmental efficiency, the complexity of the regulation of the electric field acting on the flame.

A device for burning solid household waste and garbage by fire treatment in a flame of an air-fuel mixture, comprising a cylindrical body with a combustion chamber, with a waste loading device with a filling hopper and a screw, an exhaust gas pipe, an unloading hopper, an air-fuel mixture supply and spraying device with a pipeline and a burner, a source of a strong electric field with a voltage control range from 1 kV / cm to 30 kV / cm, in frequency from 0 Hz to 30 kHz, two high-voltage electric delivery, the supply of air-fuel mixture and neutralizing liquid (water-alkaline emulsion) to the combustion zone and the automatic control system of combustion parameters as a function of the degree of environmental cleaning and toxicity sensors of exhaust gases (smoke, soot, carbon monoxide, nitric oxide, sulfur oxide and others), parameter controllers electric field (intensity, frequency), and the outputs of the sensors through the comparison units are connected to the control system of the source of the electric field (high voltage voltage converter), an electric field intensity regulator in the form of a device for mechanical vertical movement of the central electrode relative to the flame, an ionization cotter with manual transmission and an actuator, including an electric motor and an electric switch and a device with a system of spatially shifted electrodes in the transverse plane of the flame along its outer perimeter with a shift of 120 ° connected to a three-phase voltage and frequency converter, moreover, at the frequency control input of this converter Inonii sensor output exhaust gases toxicity [Russian patent RU 2117870, F23G 5/00, publ. 08/20/1998. BI №23, author Dudyshev V.D. "Method of burning waste and garbage and device for its implementation"].

The disadvantage of this technical solution is the difficulty of controlling the electric field strength, low operational reliability of the high-voltage electrode (crown) in the flame zone at high temperature.

This method of burning solid waste and garbage and a device for its implementation are selected by the authors as a prototype.

The technical result is to increase the degree of purification of combustion products and reduce energy consumption, as well as increase the reliability and simplify the device for its implementation.

The technical result is achieved by the fact that in the method of burning solid household waste and garbage, which consists in forcing solid household waste and garbage into the furnace of the boiler, in their fire treatment in a rotating flame of the air-fuel mixture by an electric field acting on them, the electric field is formed by two mutually overlapping electric fields , first they are exposed to a high-voltage voltage of negative polarity (25 ÷ 50) kV, oxidizing toxic exhaust gases with an electron beam at a current of at least (50 ÷ 10 0) μA, and then they act on the combustion products with a low-frequency alternating electric field in the frequency range (50 ÷ 1000) Hz with a voltage of (200 ÷ 1000) V, and the combustion products are neutralized until their solid phase is formed and it is separated.

The process of burning solid household waste to complete combustion of combustion products, the application of two mutually overlapping electric fields and the rotation of the combustion products in these fields provide a high degree of purification of the combustion products.

The technical result is also achieved by the fact that a device for burning solid household waste and garbage by fire treatment in a flame of an air-fuel mixture, comprising a cylindrical body with a combustion chamber, a waste loading unit, an exhaust gas exhaust pipe, an unloading unit, an air-fuel mixture supply and spraying unit with a pipeline , an electric field source, a unit for automatically controlling combustion parameters and electric field parameters regulators, according to the invention is provided with a cylindrical with an afterburner, the casing of which is made of dielectric material, a filter is installed in its upper part, and at least two pairs of electrodes are placed inside the casing, the first pair of electrodes is made in the form of a diaphragm, which has at least 8 oval holes and a hole in the center through which the central electrode passes and its ends are rigidly fixed, and the second pair of electrodes is made in the form of a Maltese cross, in the hollows of which ceramic insulators are placed, inside of which are needle high-voltage electrodes, while the electrodes of the diaphragms and Maltese crosses are fixed to the casing and separated by ring insulators, the first pair of electrodes - diaphragms connected to the source of a low-frequency alternating electric field, and in the second pair - needle high-voltage electrodes are connected respectively to the first and second outputs of the high-voltage source negative polarity, and its third output is connected to the central electrode, while the outputs of the sources are covered by feedback, in the circuit of which is installed current sensors, and their outputs are connected to inputs of amplifiers - comparators and their outputs connected to respective inputs of power sources.

The method and device for its implementation is illustrated by drawings, where:

figure 1 - a device for burning solid waste and garbage;

figure 2 - chamber electric firing afterburning of exhaust gases;

figure 3 - ceramic insulator with a needle electrode;

figure 4 - the formation of zones of afterburning of combustion products.

The device for burning solid household waste and garbage contains a boiler 1 and interconnected coolant circulation circuits, heating pipes 2, transfer and return heating pipelines 3 and 4, an expansion tank 5, a water heater 6, an air heater 7, a circulation pump 8, a jumper pipe 9, an electric fire chamber afterburning 10, body 11, chimney 12, a pair of electrodes in the form of a diaphragm 13, 14, a source of low-frequency alternating electric field 15, a pair of electrodes in the form of a Maltese cross 16, 17, a high-voltage source of negative field polarity 18, central electrode 19, the ceramic insulators 20, needle electrodes 21, annular bushings 22, filter 23, amplifier 24, comparator 29, current sensors 25, 26, 27, 28, afterburning zones: a first zone - 30; second zone - 31; the third zone - 32; the fourth zone is 33; the fifth zone is 34.

The method of burning briquettes from solid household waste and garbage and the device are similar to the process of burning coal and other materials in the furnace of boiler 1. At the bottom of the boiler 1, the heat carrier (water) is heated from the combustion of solid fuel or electric heating elements, as a result of which the warm layers of the heat carrier naturally move upwards into the expansion tank 5, which serves to collect and preserve the excess water generated by the increase in volume as a result of heating. The heated water of the boiler 1, moving through the pipes of the water heater 6, gives its heat to the water entering the heater body from the water supply system and used for needs. The expansion tank 5 also feeds the heated air heater 7, which is used to heat fresh air in winter. The expansion tank 5 is connected to the heating feed pipes 2, passing into the return heating pipes 3 and 4. To enhance the circulation of water in the heating system there is a circulation pump 8.

An electric fire afterburning chamber 10 is mounted on the chimney 12. The housing 11 is made of dielectric material, a filter 23 is installed in its upper part, and at least two pairs of electrodes are placed inside the housing, the first pair of electrodes is made in the form of a diaphragm 13, 14 having no less than 8 oval holes and a hole in the center through which the central electrode 19 passes, the ends of which are fixed, and the second pair of electrodes 16, 17 is made in the shape of a Maltese cross and ceramic insulators 20 are placed in its hollows, inside of which High-voltage needle electrodes 21 are installed, while the electrodes are fixed to the casing and separated by ring insulators 22, the first pair of diaphragms - electrodes being connected to the source 15 of a low-frequency alternating electric field, and the high-voltage needle electrodes 21 of the second pair of Maltese cross electrodes are connected respectively to the first and second outputs of the high-voltage source 18 of negative polarity, and the third output of the high-voltage source is connected to the central electrode 19. Sensors and currents 25 and 26 are included in the form of feedback, the outputs of which are connected to the inputs of the amplifier-comparator 24, and its output is connected to the input of the source 18. Current sensors 27 and 28 are included in the form of feedback, the outputs of which are connected to the inputs of the amplifier-comparator 29 and its output is connected to the input of the source 15. Figure 2 does not show the installation and method of mounting ceramic insulators 20 in the hollows of the Maltese cross 16 and 17 and the connection of the needle electrodes 21 to the first and second outputs of the high voltage source 18. Connecting one needle electric The ode is conventionally shown as a dot for simplicity and clarity (FIG. 2).

. Экспериментально измеренный ток пропорционален суммарному электрическому заряду, протекающему во времени:The afterburning process by oxidation is shown in figure 4 and is carried out in the first zone 30 and the second zone 31 as follows. A strong electric field of negative polarity is formed between the tip of the needle electrodes 21 and the central electrode 19, while electrons flow from the tip of the electrode 21. In the collision of electrons with molecules of the products of combustion and oxygen contained in the products of combustion due to incompleteness of combustion. In this case, oxygen molecules turn into negatively charged oxygen ions O ^- ,

. The experimentally measured current is proportional to the total electric charge flowing in time:

where N _e is the electron concentration;

N _j - negatively charged oxygen ions

и диссоциативным путем протекающим в продуктах сгорания по схеме

.determine from this relation (1), the degree of their influence on the afterburning process by oxidation is estimated by standard methods. Atoms and oxygen molecules have an affinity for the electron and are able to form stable negatively charged air ions. The attachment of electrons to atoms and molecules occurs under the influence of an electric field. Adhesion mechanisms are similar to recombination mechanisms: in triple collisions of the type

and dissociative flow in combustion products according to the scheme

.

The production of electrons and their density is determined by the value of the measured current flowing in the circuit when electrons flow from the tip of the needle electrode 21. The numerical value of the electrons is determined from the formula:

I, t, e - current, time, electron charge, determining the processes of afterburning by oxidation. The optimal electric field conditions are U (-) = not more than (25 ÷ 50) kV at a current I (-) = 50 ÷ 100 μA.

The effect on the afterburning processes by oxidation and the magnitude of the electric voltage can be determined from another physical representation

where T is the temperature of 700 K;

U is the voltage;

κ is the Boltzmann constant 1.38 · 10 ^-23 J / K;

e is the electron charge.

The voltage value for creating an electric discharge at the tip of the electrode 21 is determined from the relation (3): U = 30 ÷ 50 kV at a current of not more than I = 100 μA.

The experimental data on the effect of the electric field on the afterburning of combustion products are presented in the table.

The effect of the electric field on the afterburning process Afterburning mode The amount of combustion products, srvc. units C (soot) With U ₁ = 1 kB 0.3 0.5 U ₂ = 5 kV 0.05 0.3 U ₃ = 25 kV 0.016 0.08

The results of the content of combustion products show that with an increase in voltage of negative polarity and current from 13 μA to 25 μA, the content of soot and CO decreases.

In the process of burning (the influence of the electric field on the process of burning off household waste in the form of briquettes), toxic components, both gaseous dioxins and dusty components, can be formed as a result of incomplete combustion in the furnace of boiler 1. In the electric fire afterburner 10 (Fig. 2), dioxins are destroyed in the third zone where physical processes proceed as follows. The neutralization of dioxins is achieved by passing combustion products through a low-frequency (50 ÷ 1000) Hz electric field formed between the electrodes 13 and 14 during operation of the power source 15.

With a small burning power in the furnace of boiler 1, for example, no more than 10 kg / h, environmental safety is improved by arranging afterburning in the zones of two mutually overlapping electric fields, while increasing the depth of further neutralization in zones 33 and 34 (pos. 33 and 34) (a strong electrostatic field of negative polarity applied between the needle high-voltage electrodes 21 and the central electrode 19, which are connected to the high-voltage power source 18). Negatively charged electrons flowing down from the tip of the electrodes 21 are a strong catalyst (oxidizer) of the low-frequency electric field (50 ÷ 1000) Hz.

The combustion products are removed in the device through a fabric filter 23, a chimney 12. During the operation of the electric fire afterburner 10, soot can be deposited on ceramic insulators 20 and ring insulators 22 by electrodes 21 and 13, 14, which affects the loss of insulation ability and insulation resistance, which leads to to a voltage drop on the electrodes, to a decrease in the efficiency of neutralization of the combustion products and the reliability of the power supplies 15 and 18. In the event of loss of insulation, the current increases, which leads to an increase in power consumption energy blocks 15 and 18. Sensors 25 and 26 measure the current consumption. The amplifier-comparator 24, tuned to the maximum permissible current level, issues a command to turn off the output voltage from the output of the source 18. Sensors 27 and 28 measure the current consumption. Amplifier-comparator 29, tuned to the maximum permissible current level, issues a command to turn off the output voltage of source 15. Inside sources 15 and 18, high-speed switches are installed that turn off the power sources.

Then the flue gases are removed through the filter 23 and the exhaust pipe 12.

The proposed method and device provide increased environmental safety of the process of burning solid waste due to the completeness of afterburning of combustion products, increasing the reliability of the afterburner. The rational arrangement of the electrodes, the rotation of the combustion products in two mutually overlapping electric fields, significantly increases the degree of purification of exhaust gases, simplifies the design and ensures the completeness of cleaning up to 80-95%.

Claims (2)

1. The method of burning solid household waste and garbage, which consists in forcing the boiler into the furnace, in a fire treatment in a rotating flame and air-fuel mixture by an electric field acting on them, characterized in that the electric field is formed by two mutually overlapping electric fields, first they are exposed to a high-voltage negative voltage polarity (25 ÷ 50) kV, oxidizing toxic exhaust gases by an electron beam at a current strength of at least (50 ÷ 100) μA, and then affect the combustion products for a low hour alternating electric field in the frequency range (50 ÷ 1000) Hz with a voltage of (200 ÷ 1000) V, and the combustion products are neutralized to form their solid phase and it is separated. 2. A device for burning solid household waste and garbage by fire treatment in a flame of an air-fuel mixture, including a cylindrical body with a combustion chamber, a waste loading unit, with an exhaust gas pipe, an unloading unit, an air-fuel mixture supply and spraying unit with a pipe, an electric field source , a unit for automatically controlling combustion parameters and electric field parameters regulators, characterized in that the device is equipped with a cylindrical afterburner, the housing of which th is made of dielectric material, a filter is installed in its upper part, and at least two pairs of electrodes are placed inside the housing in height, the first pair of electrodes is made in the form of a diaphragm, which has at least 8 oval holes and a hole in the center through which the central electrode passes and its ends are rigidly fixed, and the second pair of electrodes is made in the form of a Maltese cross, in the hollows of which ceramic insulators are placed, inside which high-voltage needle electrodes are installed, while the electrodes the diaphragms and Maltese crosses are fixed to the body and separated by ring insulators, with the first pair of electrodes - the diaphragms connected to a source of low-frequency alternating electric field, and the second pair of needle-shaped high-voltage electrodes connected respectively to the first and second outputs of the high-voltage source of negative polarity, and the third its output is connected to the central electrode, while the outputs of the sources are covered by feedback, in the circuit of which current sensors are installed, their outputs are connected They are connected to the inputs of amplifiers-comparators, and their outputs are connected to the corresponding inputs of the power sources.

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