WO2015103679A1

WO2015103679A1 - Method for purification from dioxins and furans of flue gases obtained "from the incineration of municipal waste

Info

Publication number: WO2015103679A1
Application number: PCT/BG2014/000039
Authority: WO
Inventors: Hristo Atanasov KOVACHKI; Angel Hristov ANGELOV; Stoicho Mitrev STOEV
Original assignee: Kovachki Hristo Atanasov
Priority date: 2014-01-13
Filing date: 2014-11-05
Publication date: 2015-07-16
Also published as: BG111672A; BG66878B1

Abstract

Method for purification from dioxins and furans of flue gases by high-temperature heat treatment, such as the flue gases resulting from the combustion of solid municipal waste with temperature 800 - 1000°C are fed for mixing with gases with temperature above 1000 - 1200°C, obtained by combustion of solid, liquid or gaseous fuel, in the presence of pulse effects caused by a pulser, mounted at the inlet of the mixing point and / or in the presence rotational - screw effects caused by the tangential mounting of the gas pipes to the mixing point.

Description

METHOD FOR PURIFICATION FROM DIOXINS AND FURANS OF FLUE GASES OBTAINED TROM THE INCINERATION OF MUNICIPAL WASTE

FIELD OF THE INVENTION

Purification of flue gases from toxic components.

BACKGROUND OF THE INVENTION

To reduce the concentration of dioxins and furans in tiie flue gases from the incinerators, separation of plastic products and separate plastic components is usually applied prior to feeding municipal solid waste into the combustion installations. The aim is to remove from the mixture the component that is most responsible for the formation of dioxins and furans. At the same time, however, this is the component that includes most energy, which is lost for the energy balance of the combustion installations.

The possibility is reported for dioxins and furans to be destroyed as gasses pass through a fire filter - fire curtain with high temperature above 1000°C /Patent RU2303746 021. In this case the need to destroy tiie toxic impurities of dioxins and furans is met, but the energy benefit is almost zero, since for the creation of fire barrier considerable energy must be spent. The use of burning mixture of coal and household waste is also suggested, but as its composition is quite variable, sometimes disturbances of tiie combustion process in the boiler of the thermal power plant are found with reduction of the thermal coefficient of efficiency.

Patent WO93/00982AI also relates to a technology for individual treatment of incinerator gas and to achieve that high temperature plasma gas is used.

Patents DE3504810A1 and patent O98/03250A1 offer separation of municipal solid waste into small and large fractions, the small one is burnt together with coal in the boiler and the big in incinerator and as a guarantee of the fuller disposal of the toxic gases from the incinerator the mixing of these gases is offered with the air, fed to the burners of the boiler for coal, which, however, reduces the thermal stress on the burners due to reducing the quantity of the crushed coal passing through them:

TECHNICAL SUMMARY

The method for purification of flue gases from dioxins and furans according to the present invention is implemented by high temperature heat treatment, such as the flue gases obtained in the combustion of solid municipal waste with temperature 800 - 1000°C are fed for mixing with gases with temperature above 1000 - 1200°C, obtained in the combustion of solid, liquid or gaseous fuel. The mixing of gases takes place in the presence of pulse effects caused by a pulser, mounted at the inlet of the mixing point and in the presence of rotational-screw effects caused by the tangential mounting of the gas pipes to the mixing point. The impulse and rotational-screw effects are applied jointly or independently. With the formation of uniform gas mixture in the entire volume the dioxins and furans are destroyed by transformation into harmless mixture components.

EMBODIMENTS

Example 1

Gases from the combustion installation with temperature 800 - 1000°C are fed for mixing in the presence of intensifying factors with the gases formed in the boiler of the thermal-power plant with temperature above 1000 - 1100°C, which contributes to the completeness in the destruction of the dioxins and furans in the entire joint volume of the well homogenized mixture. As intensifying factors power impulse effects in the gas mixture are used, the effect of which in some cases may be enhanced by creating rotational-vortex effect.

The pulse effect is achieved by installing at the gas pipe to the inlet in the mixing point of gases, for example, a paddle-type pulser. The metal plates of the blades during rotation cover periodically, partially or completely the section of the gas pipe. In the time interval, when the gas pipe is half-closed, the gas is compressed, after that it is thrown out with impulse into the gas pipe. Power gas pulse effects are created with different values of the power component since the cross-section of the gas pipe varies with the narrowing of the cross-section of the opening. From here the gases at equal volume in time are thrown for mixing at different rates, hence with different power components. The latter contributes to the formation of macro and micro vortexes, which turbulate actively in the mixture, equalizing it in the entire volume, thus creating equal conditions for rapid destruction of the dioxins and furans in the entire mixture. In the turbulations of vortexes there is always an acoustic emission created by vortexes at obstacles. The acoustic emission has a power impact on the particles of ash and gas molecules, which changes the speeds of the components in the mixture, stirring them in different directions, thus increasing the number of contacts between reactants. The result is acceleration of the chemical processes of the destruction of dioxins and furans.

In the presence of rotational-screw motion of one of the gases or of both simultaneously, the time of gas presence in the mixing point and the gas pipes is increased, which reduces the chances for dioxins and furans to be transmitted before being destroyed. The rotational-screw motion is achieved by feeding the gases to the mixing point through a gas pipe positioned tangentially to the mixing point. An additional effect of the rotational-screw motion is that it increases the intensity of the vortexes formed, homogenizing the mixture.

APPLICATION OF THE INVENTION

The method for purification of flue gases from dioxins and furans according to this invention offers combustion plants for household waste to be built on the territory of thermal power plants and enterprises having combustion installation with solid, liquid or gaseous fuel and their production activity to be combined.

Thermal power stations typically bum fuel with unchangeable composition, but the composition of solid municipal waste often changes depending on the seasons, the place of formation, etc., that is why for maximum beneficial effect it is desirable to determine experimentally the optimal speeds of pulsers for pulse impact and the speeds of the exhaust gases from the tangential pipes, using valves to change the cross-section of gas pipes.

The mixing points may be chambers and gas pipes outside the waste incinerators and boilers, but also the fireplaces of boilers and the combustion installations themselves.

An additional advantage of the combined operation of the complex waste incinerators - thermal power plant is that the solid waste after being reduced in volume to about 85% when burning becomes suitable for adding to the coal in tire thermal power plant, if it contains unbumed material.

Claims

5

PATENT CLAIMS

A method for purification of flue gases from dioxins and furans by high- temperature heat treatment, characterized in that the flue gases resulting from the combustion of solid household waste with temperature 800 - 1000°C are fed for mixing with gases with temperature above 1000 - 1200°C, obtained by combustion of solid, liquid or gaseous fuel, in the presence of pulse effects caused by a pulser, mounted at the inlet of the mixing point and / or in the presence of rotational-screw effects caused by the tangential mounting of the gas pipes to the mixing point.