Two-channel burner and method of use therefor, and multi-channel single-cone burner and method of use therefor

A method for using a two-channel burner, wherein the two-channel burner comprises a pulverized coal supply mechanism, a transition channel, an inner secondary air guide tube, an outer secondary air guide tube, a combustion stabilizing chamber and a flow smoothing chamber;

• the outer secondary air guide tube, the combustion stabilizing chamber and the flow smoothing chamber are sequentially connected to form a burner body, the pulverized coal supply mechanism runs through the burner body, and the transition channel is fitted over an inlet end of the pulverized coal supply mechanism;
• the inner secondary air guide tube is arranged between the transition channel and the outer secondary air guide tube, an inner secondary air passage is formed between the inner secondary air guide tube and the transition channel, and an outer secondary air passage is formed between the inner secondary air guide tube and the outer secondary air guide tube;
• an outlet end of the inner secondary air guide tube forms a flared opening, the flared opening has a same angle as the combustion stabilizing chamber, and a direction of an outlet end of the inner secondary air passage is parallel to a wall surface of the combustion stabilizing chamber;
• and
• the pulverized coal supply mechanism comprises an air-pulverized coal duct and a rich/lean separator, the air-pulverized coal duct is on a central axis of the burner body and in connection with the combustion stabilizing chamber, and the rich/lean separator is detachably connected to the air-pulverized coal duct to make pulverized coal fed into the combustion stabilizing chamber present an inner rich and outer lean concentration distribution or an inner lean and outer rich concentration distribution;
• wherein the method comprises:
• step (1):
• a corresponding rich/lean separator is selected and mounted on the air-pulverized coal duct according to a coal type;
• step (2):
• air enters the burner body in two ways, one of which passes through a movable axial impeller assembly and the inner secondary air passage, so that rotating inner secondary air with a tangential velocity is formed and directly enters the combustion stabilizing chamber, and the inner secondary air passage and the transition channel work together to form a nested high-temperature backflow zone;
• step (3):
• meanwhile, an airflow entrained with pulverized coal is injected into the combustion stabilizing chamber through the air-pulverized coal duct and the rich/lean separator, the pulverized coal presents an inner rich and outer lean concentration distribution or an inner lean and outer rich concentration distribution, the pulverized coal is preheated to 900-1000° C. through the high-temperature backflow zone, and the pulverized coal is pyrolyzed in the low-oxygen and hot high-temperature backflow zone and is mixed with the inner secondary to form a main flame;
• and
• step (4):
• the other way passes through the outer secondary air passage, to form outer secondary air;
• a part of the outer secondary air passes through the flared opening of the outer secondary air guide tube and forms a cooling air layer flowing along the wall surface of the combustion stabilizing chamber to cool the combustion stabilizing chamber and the flow smoothing chamber;
• and another part of the outer secondary air and the main flame form a high-speed jet flame wrapped in air, by the flow smoothing chamber, and the high-speed jet flame enters a furnace.

A multi-channel single-cone burner, comprising a pulverized coal supply mechanism, a transition channel, a multi-stage air distribution assembly, a guide plate, a combustion stabilizing chamber, and a flow smoothing chamber, wherein:

• the multi-stage air distribution assembly comprises N air guide tubes arranged coaxially from inside to outside, and N is a natural number not less than two, wherein an Nth air tube is connected to the combustion stabilizing chamber and the flow smoothing chamber sequentially to form a burner body, the pulverized coal supply mechanism runs through an interior of the burner body, the transition channel is fitted over an inlet end of the pulverized coal supply mechanism, and a first air guide tube is fitted over and spaced apart from the transition channel, so that a total of N air inlet channels are formed between every adjacent two air guide tubes and between the first air guide tube and the transition channel;
• meanwhile, except for the Nth air guide tube, each of the other air guide tubes has a double-layer hollow structure, an annular groove extending axially is on an inner side of each of the other air guide tubes, and a first end of at least one guide plate is inserted into the annular groove of the corresponding air guide tube and is fixed;
• and
• at least one straight flow channel is formed between each guide plate and the combustion stabilizing chamber, and a second end of each guide plate is formed with a flared opening that has a same angle as the combustion stabilizing chamber, so that a direction of an outlet end of the straight flow channel is parallel to a wall surface of the combustion stabilizing chamber.