COMPOUND CATHODE AND DEVICE FOR PLASMA FIRING ON THE BASE OF COMPOUND CATHODE Russian patent published in 2005 - IPC

FIELD: plasma firing of dust-type coal.

SUBSTANCE: device for direct firing of boiler on the base of dust-type coal has plasma generator, burner feeding with dust-type coal, plasma generator arm and dc source. Plasma generator has compound cathode, electromagnet coil, coil for moving arc and linear engine. Dust-type burner has pipe for dust-air mixture, pipe for entering first stage combustion chamber, entrance pie for initial dust-air mixture, first stage combustion chamber, second stage combustion chamber, third stage combustion chamber, fourth stage combustion chamber, burner's nozzle and guiding plate for adjusting powder content. Compound cathode has head of cathode, bushing for starting arc, sealing nuts, plate of cathode, cooling nozzle, electro-conducting tube, water feed pipeline, tube for letting water in, pipeline for letting water out and cap mounted at the end of cathode. Plate of cathode is made in form of cylinder plus cone and it is fastened to head of cathode by welding. It is made of material on the base of Ag to have high electric and heat conductivity. Aluminum oxide is also capable of conducting electric current. Nozzle is made in form to converge and to diverge by the end. Compound anode of plasma generator has sealing ring, case of anode, and cavity for cooling water, nozzle of anode, anode body, base of anode, water feed pipeline and water discharge pipeline. Compound anode is made by welding of two tubes having nozzles. One end of compound anode is welded to nozzle of anode and the other end is welded to base of anode. Case of anode is made of alloy on the base of Ag and nozzle of anode is made of alloy on the base of copper and Ag. Compound anode is embraced with coil for moving arc. Dust-type burner has nozzle of burner, first to fourth combustion chambers, tube for dust-air mixture, entrance pipe for initial dust-air mixture, guiding plate for primary dust-air mixture, guiding plate for adjusting content of powder. All those units are fastened together by welding with connecting plate or by means of bolts. Flow of dust-type coal coming in through the tube for initial dust-air mixture is divided to three flows to pass through guiding plate of first stage combustion chamber, guiding plate of second stage combustion chamber and guiding plate for initial dust-air mixture to fist to third stage combustions chambers correspondingly. Ancillary air coming from tube for letting ancillary air in divides to three flows which cool external cylinder of first stage combustion chamber, third stage combustion chamber and external wall of fourth stage combustion chamber. Part of ancillary air enters space between inner wall of fourth stage combustion chamber and outer wall of first stage combustion chamber to add oxygen for making process of burning easier. Direction of flow of high content dust-type coal in first stage combustion chamber changes by means guiding plate of first stage combustion chamber from radial flow to axial one. Guiding plate for adjusting powder content intends for adjusting content of dust-type coal till value making ignition easier.

EFFECT: continuous and stable operation of generator; improved reliability of exploitation of burner.

11 cl, 7 dwg