Double cyclone pulverized coal burner

Abstract

The invention belongs to a dual-cyclone powder coal burner for power plant boilers; the invention comprises a central fan drum with a fuel gun and a Venturi segment as well as a bunching tube; a main nozzle with a flow channel and a Venturi segment inside a diversion collar and with a flared edge; a secondary air nozzle composed of a cyclone generator and a governor valve; a third air nozzle composed of a cyclone generator and a horn-shaped opening, as well as a corresponding air intake. The invention can effectively improve the radial distribution effects of interior thicker and exterior thinner in powder coal concentrate at a main spout of the burner; therefore, the invention has the perfect dense-light separation effect for powder coal; both the secondary and third air flowrate can be regulated conveniently; the flowrate ratio on the dense-light side is RQ being 0.9 to 1.0; the powder coal concentrate ratio on the dense-light side is Rc higher than 4.5; the flowing resistance factor is low and the flow speed distribution at the spout is ideal; the invention adapts to use together with boilers with rather high adaptability for coal specifies and load variations; the invention is characterized by perfect combustion stability, low emission of nitrogen oxides, and effectively avoiding fuel gun abrasion and pitting on the nozzles, as well as long service life and etc.

Description

technical field [0001] The invention belongs to the jet type swirl burner used in conjunction with power plant boilers burning pulverized coal, in particular to a double swirl pulverized coal burner in which the concentration of pulverized coal at the main nozzle of the burner is radially distributed to be rich inside and light outside. The burner is matched with the corresponding boiler to realize ideal rich-lean combustion. Background technique [0002] Double-swirl pulverized coal burners are widely used in power plant boilers that use pulverized coal to achieve thick-lean combustion. At present, it is mainly a jet-type double air-regulating swirl burner, such as the "burner" disclosed in the patent document CN1125308A and titled "Powdered Coal Burner", which belongs to this type of swirl pulverized coal burner. The burner includes a built-in oil gun and an annular throat on the pipe wall. A split ring (partition wall) is arranged around the center line between the throa...

AI Technical Summary

Problems solved by technology

However, due to the one-time separation of the main nozzle with a simple throat, the separation effect of the thick and light coal powder is poor. The flame stabilizer composed of annular plates, the annular plate of the stabilizer vertically extends into the flow channel of the main nozzle outlet, and its function is to act as an obstacle to hinder the primary airflow (main nozzle airflow) to reduce its downstream Air pressure helps to ignite pulverized coal; although the setting of the stabilizer helps to ignite pulverized coal and stabilize combustion, due to the hindrance of the first-stage (main nozzle) airflow, a jet in the direction opposite to the ejection direction is formed near the nozzle. The recirculation zone not only further increases the resistance of the first-stage wind, but also further reduces (destroys) the thick-lean separation effect of the pulverized coal at the upstream part of the main nozzle; in addition, the burner does not have a central air duct and the boiler operates During the process, the flame rushes into the nozzle with the power of backflow, which is easy to ablate the nozzle and flame stabilizer; and if the oil gun is directly installed in the main nozzle, the oil gun is also easily worn by high-speed coal powder

Therefore, this background technology has disadvantages such as poor separation effect of thick and thin coal powder, which affects the effective application of thick and thin combustion technology, poor adaptability to coal quality changes during operation, easy wear of oil guns, and easy ablation of nozzle mouths.

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