초록 ▼

This invention relates to a plasma igniter for directly igniting the pulverized coal burner. Said plasma igniter consists of a plasma generator which includes a composite anode, an combined type cathode, an electromagnetic coil and a transmitting coil; a pulverized coal burner which comprises multi-

This invention relates to a plasma igniter for directly igniting the pulverized coal burner. Said plasma igniter consists of a plasma generator which includes a composite anode, an combined type cathode, an electromagnetic coil and a transmitting coil; a pulverized coal burner which comprises multi-stage chambers for conveying igniting coal, an equipment for adjusting concentration of coal powder and a four-stage burner canister; and a generator brace. Said combined type cathode consists of a cathode plate, a fixation nut, a conductive pipe, an inflowing pipe, an inflowing guiding pipe, a cathode lid and a sealing spacer. The lining for generating electric arc is assembled with the front of cathode. An alloy plate is used as the cathode plate. The nozzle that used for cooling the cathode is first convergent and then expansive, and is placed in the middle of the conductive pipe. The plasma igniter has the advantage of stable burning. It can be used as not only a main burner for the boiler but also an igniting burner. Since oil is not used, lots of petroleum source is saved.

대표청구항 ▼

The invention claimed is: 1. A plasma ignition device for directly igniting a pulverized coal boiler, comprising a plasma generator, a pulverized coal burner, and a dc power supply for supplying electric power to the plasma generator, wherein said plasma generator comprises a cathode, an anode, an

The invention claimed is: 1. A plasma ignition device for directly igniting a pulverized coal boiler, comprising a plasma generator, a pulverized coal burner, and a dc power supply for supplying electric power to the plasma generator, wherein said plasma generator comprises a cathode, an anode, an electromagnetic coil disposed around a space between the cathode and the anode when the cathode is moved away from the anode, and a linear motor for driving the cathode back and forth to contact the anode or move away from the anode, and wherein said pulverized coal burner comprises an external cylinder, at least two stages of burning chambers arranged in the external cylinder and cascaded one after another, inlet tubes respectively for said at least two stages of burning chambers, a primary air-pulverized coal tube for supplying an air-pulverized coal mixture of air and pulverized coal to said inlet tubes of said at least two stages of burning chambers, an auxiliary air inlet tube for supplying auxiliary air into the external cylinder, and a burner nozzle in an end of a last stage burning chamber, wherein the plasma generated by an arc discharging between the cathode and the anode will ignite the air-pulverized coal mixture in a first stage burning chamber, which further ignites the air-pulverized coal mixture in the next stage burning chamber, and wherein the auxiliary air or air-pulverized coal mixture flowing between walls of the respective stages of the burning chambers or between the external cylinder and outside walls of the respective stages of the burning chambers cools the walls of the respective stages of the burning chambers. 2. The plasma ignition device according to claim 1, wherein said cathode is a combined cathode comprising a cathode head, an arc-starting bush mounted on the cathode head, a cathode plate surrounded by the arc-starting bush, a cooling nozzle for cooling the cathode plate with water, an electrically conductive tube connected at one end to the arc-starting bush, a water supply inlet tube for supplying said water located at an opposite end of the electrically conductive tube, a water inlet pipe in said electrically conductive tube for supplying said water from said water supply inlet tube to said cooling nozzle, a water outlet tube for discharging said water mounted to the electrically conductive tube, and a cathode end cap at said opposite end of the electrically conductive tube. 3. The plasma ignition device according to claim 2, wherein said cathode plate is in the shape of a cylinder plus a cone, and is attached to the cathode head through welding, and is made of an Ag-based material, which is a highly electrically conductive and a highly thermally conductive medal, and an oxide of which is also conductive, the cooling nozzle being constructed so that it is convergent first and then divergent. 4. The plasma ignition device according to claim 1, wherein said anode is a composite anode comprising an anode housing, an anode nozzle, an anode body, an anode base, a water supply tube and a water outlet tube, wherein one end of said anode housing is welded to the anode nozzle, and an other end is welded to the anode base, and wherein the anode nozzle, the anode body and the anode base are integral, and both the water supply tube and the water outlet tube are communicated with a cavity of cooling water defined between an inner wall of the anode housing and an outer wall of the anode nozzle, the anode body, and the anode base. 5. The plasma ignition device according to claim 4, wherein said anode body is made of an Ag-based alloy, and the anode nozzle is made of copper or an Ag-based alloy. 6. The plasma ignition device according to claim 4 or 5, wherein said composite anode is surrounded by an arc transporting coil. 7. The plasma ignition device according to claim 1, wherein said at least two stages of burning chambers comprise a first stage burning chamber, a second stage burning chamber, a third stage burning chamber, and a fourth stage burning chamber, and the pulverized coal burner further comprises a primary air-pulverized coal guide plate, and a pulverized coal-concentration-adjusting guide plate, wherein the air-pulverized coal mixture flowing through the primary air-pulverized coal tube is divided into three streams, which respectively pass through a guide plate for the first stage burning chamber, a guide plate for the second stage burning chamber and the primary air-pulverized coal guide plate, respectively into the first stage burning chamber, the second stage burning chamber, and the third stage burning chamber, the auxiliary air coming from the auxiliary air inlet tube being divided into three streams, which respectively cools an external wall of the first stage burning chamber, an external wall of the third stage burning chamber, and an external wall of the fourth stage burning chamber, a portion of the auxiliary air entering into an inner wall of the fourth stage burning chamber and the outer wall of the first stage burning chamber so as to supplement oxygen for facilitating combustion, the air-pulverized coal mixture in the first stage burning chamber being changed by the guide plate for the first stage burning chamber from radial flow into axial flow, and the pulverized coal-concentration-adjusting guide plate adjusting the concentration of the pulverized coal to a concentration facilitating ignition. 8. A combined type cathode, comprising a cathode head, an arc-starting bush mounted on the cathode head, a cathode plate surrounded by the arc-starting bush, a cooling nozzle for cooling the cathode plate with water, an electrically conductive tube connected at one end to the arc-starting bush, a water supply inlet tube for supplying said water located at an opposite end of the electrically conductive tube, a water inlet pipe in said electrically conductive tube for supplying said water from said water supply inlet tube to said cooling nozzle, a water outlet tube for discharging said water mounted to the electrically conductive tube, and a cathode end cap at said opposite end of the electrically conductive tube. 9. The combined type cathode according to claim 8, wherein the arc-starting bush is made of a graphite rod, which has a high fusion temperature and a high electrical conductivity, the arc-starting bush being fastened on a front end of the cathode head through a screwed connection, and being flush with the cathode plate. 10. The combined type cathode according to claim 8 or 9, wherein the cathode plate is joined to the cathode head through brazing, and a surface thereof is flush with the arc-starting bush. 11. The combined type cathode according to claim 8, wherein said cathode plate is in the shape of a cylinder plus a cone, and is attached to the cathode head through welding, and is made of an Ag-based material, which is a highly electrically conductive and a highly thermally conductive material, and an oxide of which is also conductive, the cooling nozzle being constructed so that it is convergent first and then divergent.