Novel ignition mode application of 300MW circulating fluidized bed boiler

Abstract

The invention discloses novel ignition mode application of a 300MW circulating fluidized bed boiler. Current domestic earliest 300MW circulating fluidized bed boiler units have gone into operation formany years, and due to the fact that fire coal quality is poor and fire coal is prone to being ignited, starting oil consumption of the units is high. The novel ignition mode application is characterized in that only a primary fan is started at the initial stage of ignition, other fans are shut down, and the primary air volume is adjusted, so that the boiler is in a micro bubble state. Accordingto the novel ignition mode, (1) the proper bed thickness and grain size are confirmed, wherein the material layer thickness is controlled to range from 800 mm to 900 mm; (2) cold state fluidization testing is carried out before starting, wherein bed materials are fed before the circulating fluidized bed boiler is started every time, the bed materials are conveyed into a hearth through a scraping plate coal feeder by starting a bed material system, and fluidization testing of the bed materials is carried out; (3) the temperature before ignition of the boiler is improved, wherein the pressure ofa heating heat source can be improved to 3.9 MPa from 0.8 MPa; (4) heat losses during oil feed are reduced, wherein the outlet pressure of a hearth is adjusted to range from 50 Pa to 100 Pa through an inlet and outlet valve of an induced draft fan; and (5) the proper bed temperature is selected to feed coal correctly. The novel ignition mode application of the 300MW circulating fluidized bed boiler is achieved.

Description

Technical field: [0001] The invention relates to the application of a novel ignition method for a 300MW circulating fluidized bed boiler. Background technique: [0002] For the 300MWCFB circulating fluidized bed boiler, the earliest domestic 300MW circulating fluidized bed unit has been put into operation for many years. Due to the coal quality (air drying base volatile content 15%, received base low heating value 10.1MJ / kg, moisture 11 %, the ash content of the air-dry base is 65%) is not easy to ignite, and the unit starts fuel consumption is higher. According to the analysis of multiple boiler start-ups, the key to saving fuel is to reduce the heat loss of the boiler during the fueling period, and use all the fuel heat to heat the bed material as much as possible. At the same time, reduce the time from coal charging to the complete ignition of the coal and increase the boiler temperature before ignition. Unit start-up fuel consumption; indirect measures that affect fuel consu...

AI Technical Summary

Problems solved by technology

[0004] Since the circulating fluidized bed boiler is designed with an air distribution plate, a certain amount of bed material is arranged on it when starting up, and the primary fluidized air in the air duct combustion chamber is heated into high-temperature hot flue gas through the combustion of an oil gun under the bed, and then passed through the air distribution The plate hood evenly heats the bed material on the main bed, so that the bed temperature rises until the bed material is heated above the minimum temperature level required for coal feeding, so as to realize a process of coal feeding; it is precisely because of the characteristics of the circulating fluidized bed itself The circulating fluidized bed boiler is different from the conventional pulverized coal furnace in structure and combustion principle. The particle size of the circulating material determines that the combustion of the circulating fluidized bed boiler cannot be carried out quickly in an instant. Safe temperature rise speed, the start-up of circulating fluidized bed boiler can only be a slow heating process, there are common problems such as long start-up time, large fluctuations in bed temperature during start-up, and large start-up fuel consumption; therefore, the pursuit of circulating fluidized bed boiler ignition The goal is to use the shortest time and the least amount of fuel to heat the bed material to the coal feeding temperature to realize coal feeding, shorten the ignition time, and minimize the fuel consumption for starting the furnace under the premise of having the least impact on the life of the boiler.