High efficiency cyclone gasifying combustion burner and method

Abstract

A cyclone gasifying combustion burner and its operation is described. An exemplary burner has an inner cylindrical wall with a contour chamber feeding combustion air into the inner cylindrical wall, with an open end and a solid fuel support end where a combustible material forms a fuel bed. The inner cylindrical wall has a series of inclined air jet holes of substantially predetermined diameter and disposed at substantially predetermined locations therein to create a unidirectional cyclone within a combustion zone defined within the inner cylindrical wall. The air jet holes are disposed at a tangential and vertical angle whereby the combustion air is drawn into the inner cylindrical wall and creates a cyclone flow to mix with the combustion gases released from the flaming pyrolysis fuel bed and causes the combustion gases to flow in a cyclone path within a reaction zone to increase the residency, mixing and turbulence time of the combustion gases and simultaneously precipitate suspended particles against an inner surface of the inner cylindrical wall whereby the particles are caused to gravitate to the fuel bed where they are removed in a controlled manner during the operation of the burner.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims priority to Canadian Patent Application No. ______, filed on Dec. 15, 2005, and entitled “High Efficiency Cyclone Gasifying Combustion Burner to Produce Thermal Energy and Devices and Method of Operation”, and hereby incorporated by reference. TECHNICAL FIELD [0002] The present invention relates in general to fuel burners, and in particular to a high-efficiency cyclone gasifying combustion burner and methods of operation. BACKGROUND ART [0003] In U.S. Pat. No. 6,336,449, a solid fuel burner is disclosed of cylindrical shape with holes disposed in an inner cylindrical wall to create a swirling motion to burn the combustion gases. Further experimental work and testing of this concept has led to important improvements beneficial to human health. [0004] There has been a considerable increase in the use of wood-burning devices to heat residential buildings. This increase has been precipitated by the high cost of oil a...

AI Technical Summary

Benefits of technology

[0014] In accordance with various aspects of the present invention, a cyclone gasifying combustion burner is configured for use in or coupled to a solid fuel biomass device that substantially eliminates various disadvantages of wood-stoves or other solid fuel combustion devices. For example, an exemplary burner and method of operation can substantially reduce the emission levels of volatile organic compounds (VOC), particulates and fly ash as well as the level of nitrogen oxide (NOx) and / or all other carbon and volatile gases released during combustion of a solid fuel.

[0015] In accordance with an exemplary embodiment, a cyclone gasifying combustion burner can be incorporated into or coupled to a device having a thermal energy source and that can be automatically controlled in a modulated manner to achieve optimum efficiency. Such a cyclone gasifying combustion burner can comprise a fuel bed support system, such as a pyrolytic fuel bed, that automatically removes ashes from the fuel bed and thereby substantially reduces emission of volatile organic compounds, particulates, fly-ash, nitrogen oxides and other pollutants into the atmosphere. In accordance with another aspect, a cyclone gasifying combustion burner can also be configured such that the fuel bed temperature is starved of combustion air whereby to reduce the temperature of the fuel bed to prevent the fusion of inorganic elements within the solid fuel. An exemplary cyclone gasifying combustion burner may also be coupled to heating devices for residential, commercial and industrial applications, whereby to replace fossil fuel dependent heating devices. Such heating devices incorporating the cyclone gasifying combustion burner can also be configured to achieve significant reduction of greenhouse causing gases.

[0016] In accordance with an exemplary embodiment, a cyclone gasifying combustion burner comprises a combustion housing defined by an inner cylindrical wall surrounded by a manifold chamber having combustion air inlet devices and mechanisms. The inner cylindrical wall has air jet holes therein of substantially predetermined diameter and disposed at a substantially predetermined angle to create an air cyclone flow in a reaction zone in the inner cylindrical wall and spaced above a lower air-starved gasifying fuel bed thereof. The cyclone flow in the reaction zone can increase the residency time, turbulence, and mixing of oxygen and volatile gases to substantially complete combustion of the gases drawn into the reaction zone and causes suspended particles to gravitate into the fuel bed and thereby substantially reduce the emission of pollutants into the atmosphere.

[0019] In accordance with another aspect of the present invention, there is provided a method of substantially reducing the emission levels of volatile organic compounds (VOC), particulates entrained fly ash, and the level of nitrogen oxides (NOX) during combustion of a solid fuel. In accordance with an exemplary embodiment, an exemplary method comprises the steps of feeding the solid or gas fuel in particle-form into an open end of a cyclone gasifying combustion burner and onto a flaming pyrolysis fuel bed thereof. The fuel bed is disposed below a reaction zone of the burner. The burner has a burner chamber defined by an inner cylindrical wall having a predetermined number of inclined air jet holes of predetermined diameter and height disposed at substantially predetermined locations to create a cyclone air flow within the reaction zone when combustion air is drawn therethrough. Air is drawn into the burner chamber through the inclined air jet holes whereby to draw combustion gases from the fuel bed into the reaction zone to mix with the cyclone air flow thereby substantially increasing the residency time of the combustion gases in a turbulent, mixing of oxygen and volatile gases for substantially complete combustion of gases and tars in the reaction zone and to simultaneously precipitate suspended particles against an inner surface of the inner cylindrical wall to cause at least some of the particles to agglomerate with other particles to increase their molecular weight and gravitate to the fuel bed.

[0022] In accordance with an exemplary embodiment, there is provided a cyclone gasifying combustion burner having a combustion housing defined by an inner cylindrical wall surrounded by a manifold chamber having a combustion air inlet mechanism or system. The inner cylindrical wall has air jet holes therein of predetermined diameter and disposed at a predetermined angle to create an air cyclone flow in a reaction zone in the inner cylindrical wall spaced above a lower combustion gas supply. The cyclone flow in the reaction zone increases the residency time, turbulence, mixing of oxygen with volatile gases for substantially complete combustion of gases drawn in the reaction zone thereby substantially reducing the emission of pollutants into the atmosphere.

[0023] In accordance with an exemplary embodiment, a method of substantially reducing the emission levels of any one of volatile organic compounds (VOC), particulates, entrained fly ash, and / or the level of oxygen oxides (NOx) during combustion of a gas can comprise supplying a combustion gas from below a reaction zone of a cyclone gasifying combustion burner. For example, the burner can comprise a burner chamber defined by an inner cylindrical wall having a substantially predetermined number of inclined air jet holes of substantially predetermined diameter disposed at substantially predetermined locations to create a cyclone air flow within the reaction zone when combustion air is drawn therethrough. The method further comprises drawing air into the burner chamber through the inclined air jet holes whereby to draw the combustion gases into the reaction zone to mix with the cyclone air flow thereby increasing the residency time of the combustion gases, turbulence, and mixing of oxygen with volatile gases for substantially complete combustion of gases in the reaction zone to substantially reduce the emission of pollutants into the atmosphere.

Problems solved by technology

This increase has been precipitated by the high cost of oil and gas.

However, these wood-burning devices pollute the atmosphere and are harmful to human health.

Smoke from the combustion of wood is present in both inside and outside the home.

At the local level, wood combustion may contribute far more severely to pollution.

In addition to emitting contaminants outdoors, wood combustion units may alter the quality of the air inside the home as portions of the combustion gases and fine particles make their way back indoors.

The combustion of wood thus represents an additional source of exposure to toxic substances in the home.

Some of these minerals occurring substantially as potassium and chlorides, which may have lower melting points than for example silicates, pose many difficulties during and after combustion of the fuel, as they promote the agglomeration (by melting and or cooling into masses) of minerals on adjacent metal surfaces.

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