Latest Technology and Innovative Applications for Chain and Cross-beam Grates in Wafangdian
Chain grate
Traditional chain-grate boilers use a single “grate firing” method, while a combined combustion control system for chain-grate boilers now combines grate firing with chamber firing. In this system, part of the coal from the coal supply system is pulverised into ultra-fine coal powder by a coal mill and then injected into the furnace by a pulverised-coal burner for suspension combustion, while the rest of the coal is fed directly onto the boiler grate.
Combined combustion control system
An intelligent controller can precisely control the coal consumption of both parts and adjusts the air volume of the pulverised-coal exhaust fan according to the flame intensity in the boiler. This combined combustion method raises the furnace temperature, slows the grate running speed and thins the coal bed, prolongs the combustion time of the coal on the grate, increases the ventilation coefficient of the coal bed and reduces the carbon content of the slag, thereby improving both boiler output and thermal efficiency and meeting the requirements of energy saving and environmental protection.
Tail-end waste heat energy-saving and environmental protection devices
In some chain-grate hot water boilers, tail-end waste heat energy-saving and environmental protection devices such as waste heat boilers, air preheaters and dust removal and desulphurisation settling chambers have been added. The waste heat boiler is connected to the boiler body through a flue, which increases the heating surface and the water capacity and can save 15%-20% of coal on a comparable basis. The air preheater raises the temperature of the hot air entering the furnace and thus the furnace temperature, and its tubes are arranged in a vertical structure, so ash accumulation is not easy.
The dust removal and desulphurisation settling chamber lets solid particles such as flue dust settle under gravity, and by adding lump lime to react with the sulphur dioxide in the flue gas it achieves the environmental protection purpose of dust removal and desulphurisation. This device not only improves the energy utilisation rate but also effectively reduces operating and maintenance costs.
Structural design of the new chain-type grate
For example, a new type of chain grate adds components such as baffles, a heat dissipation mechanism, a dust cleaning brush and a dust collecting funnel. The baffles prevent objects from falling off both sides of the grate during operation and are easy to remove and replace.
The heat dissipation mechanism blows air onto the grate through fans and effectively solves the heat dissipation problem of the grate. The dust cleaning brush continuously cleans the ventilation holes of the grate and prevents dust from blocking them. The dust collecting funnel forms a sliding structure with the base through a slide groove, which makes it easy to take out the ash produced and improves the practicability and maintenance efficiency of the device.
