TECHNICAL FIELD

The present invention relates to a microwave gasification furnace which uses a microwave generator to carry out gasification of all products and substances that are subject to gasification or degasification. The furnace is intended for gasification of substances and extraction of fuel gas and for effective recuperation of heat generated in the process. The furnace may be applied in households or industrial plants.

BACKGROUND ART

Known and used are furnaces for microwave gasification of biomass fitted with an externally arranged magnetron controlled by an external power supply and control unit, with a steel housing in the form of a cylinder or a cuboid, with insulated walls to prevent overheating of the outer furnace housing in the process. The known furnaces have apparatus for injecting inert gas into the furnace chamber to ensure oxygen-free conditions of the gasification process. Known are also microwave furnaces for industrial waste incineration - (hazardous waste predominantly). The known furnaces are mainly used for industrial purposes.

DISCLOSURE OF THE INVENTION

The object of the invention is a microwave gasification furnace comprising a process chamber, a metal housing and a magnetron, equipped with power supply and control system, characterised in that a water jacket with a separate steam generation chamber is arranged within the furnace housing, whereby the remaining part of the water jacket forms a heat exchanger with coolant inlet and outlet, while the steam chamber has a water supply inlet and a steam outlet. The process chamber is provided with a connector pipe for releasing gaseous products of the technological process, with a gas pressure safety valve, and a connector pipe for injecting process gas and air dosing. The top part of the housing is closed with a lid, on which a magnetron is arranged, and the bottom part is closed with a flap, in which an outlet for liquid products obtained from the process is arranged. The steam outlet, arranged in the upper part of the side wall of the housing, is provided with a three-way valve for injecting steam into the process chamber or discharging it outside the furnace. The steam outlet in the process chamber is preferably provided with an expansion nozzle. The steam chamber is provided with a water gauge.

The solution according to invention is applicable in particular in households and small industrial plants. The furnace may be used for microwave gasification of any products to produce combustible gas from decomposition of such products and domestic hot water from the furnace water jacket cooling.

The design of the furnace allows the process to be carried out in two stages: first, feedstock gasification with no air and discharge of combustible gas obtained as a result of such decomposition, and then, after injecting steam, additionally obtaining fuel gas (CO) from carbon which remained after decomposition of feedstock in the first stage.

BRIEF DESCRIPTION OF THE DRAWING

The embodiment of the invention is illustrated in Fig. 1 which shows an external view of the microwave gasification furnace, whereby all elements that are comprised within the furnace are indicated with dashed lines.

EXAMPLE FOR CARRYING OUT THE INVENTION

The microwave gasification furnace contains a magnetron 10, equipped with power supply and control system 12 and a metal housing 1 with the top part closed with a lid 6, and the bottom part closed with a flap 13. The water jacket 3 with a separate steam generation chamber 5 is arranged within the furnace housing 1. The remaining part of the water jacket 3 forms a heat exchanger 4 with coolant inlet and outlet. The steam chamber 5 has a water supply inlet 18 and a steam outlet 9. The interior of the furnace comprises a process chamber 7 to which the feedstock to be subject to microwave gasification is fed. The process chamber 7 is provided with a connector pipe 16 for releasing the gaseous products of the technological process and a connector pipe 17 for injecting process gas and air dosing, depending on the technological process. The magnetron 10 is arranged on the lid 6. In the bottom flap 13, an outlet 8 for liquid products obtained from the process is arranged. The steam outlet 9 from the steam chamber 5 is arranged in the upper part of the side wall of the housing 1. The steam outlet 9 from the steam chamber 5 is provided with a three-way valve 9A for injecting steam into the process chamber 7 or outside the chamber, depending on the technological process. The steam outlet 1 1 in the process chamber is preferably provided with an expansion nozzle 20, which allows the steam to be uniformly supplied to the process chamber. The steam chamber 5 is fitted with a water gauge 19 and a pressure gauge 15 which is used to control the pressure of steam generated in the chamber. The connector pipe 16 for releasing the gaseous products of the technological process is provided with a gas pressure release valve 14.

The operation of the apparatus is as follows: the product to be gasified or degasified is fed into furnace chamber 7 through feedstock lid 6. Then, the water jacket 3 is filled with water or other liquid coolant, so that the heat exchanger chamber 4 is completely filled, and the steam chamber 5 is, through inlet 18, half filled with water according to indications of the water gauge 19. After the feedstock lid 6 is closed, the magnetron 10 is turned on via magnetron control part 12. The coolant outlet or inlet 2 may be connected to a heat receiver, e.g. a boiler or radiator, to fully recover the waste heat. The temperature of a property cooled furnace should not exceed the boiling point of the coolant cooling the process chamber. After starting the magnetron, the process takes place according to the type of feedstock. After reaching the operating pressure, the gaseous products open the gas pressure release valve 14 and are injected into the gas receiver via connector pipe 16. The heat generated in the gasification process in the chamber is intercepted by the cooling liquid in the heat exchanger 4 and by water in the steam chamber 5 which rapidly turns into steam. The steam may be used for gasification of decomposition products remaining after the first stage (degasification stage). To achieve this, steam is injected, through a tree-way valve 9A, into the process chamber in which the carbon-containing products are gasified and coke gas is obtained. The gas obtained is discharged through outlet 16. Where it is necessary to turn off the steam, the steam is discharged, through a three-way valve, outside the furnace. After completing the process, the liquid products are discharged through outlet 8. After the liquid products are discharged, the bottom flap 13 is opened and the solids are removed.

The microwave gasification furnace may be used for completely oxygen- free degasification or for degasification utilising small amounts of oxygen or other gas, depending on feedstock characteristics and requirements of the final product and for obtaining fuel gas which can be used as an energy source.

Through the use of the steam chamber, the furnace may be utilised for coke gasification to produce high-quality coke gas. The furnace is advantageous in that the temperature and process efficiency may be controlled by reducing the power of the microwaves.