A process for burning petroleum coke in a cfb boiler

Abstract

The invention discloses a petroleum coke mixed burning process using a CFB boiler. The process comprises the steps that materials are mixed and prepared, and limestone powder is blown from four limestone powder pipelines to a stokehold to be mixed and stirred with petroleum coke through clap valves; a material bed is used for conveying the materials to a combustion chamber of the boiler, the bed temperature of the material bed is controlled to be 870-940 DEG C, and the bed pressure is controlled to be 3.5-5.5 kPa; sand is regularly added to the material bed; after the sand is added, the materials are fed into the combustion chamber for high-temperature combustion; and after the materials are combusted at high temperature in the combustion chamber, the solid waste is returned to the combustion chamber through a bed material returning device, the smoke after passing a rear smoke channel is separated from materials and then is returned to the combustion chamber through a recirculating machine, and the redundant gas is discharged through a chimney. According to the process, abrasion of the heated surface of the boiler is effectively reduced, the service life of the wear-resistant casting material in the boiler is prolonged, and the maintenance amount of the casting material is reduced; and the bottom slag amount of the boiler is reduced, and after a bottom slag system is properly transformed, the bottom slag system can normally run.

Description

technical field [0001] The invention relates to a boiler technology, in particular to a process for burning petroleum coke in a CFB boiler. Background technique [0002] The boiler is a high-pressure, single-drum, natural circulation fluidized bed boiler with an evaporation capacity of 220 tons per hour. Two adiabatic high-temperature cyclone separators are arranged outdoors, with a single furnace body and a slightly inclined furnace bottom. During operation, the air is distributed through the bed. The primary wind speed of the plate is higher than the critical fluidization velocity, the bed expands, the bed material is carried away from the bed by the flue gas, and the large particles carried are separated by the high-temperature cyclone separator and returned to the bed to form a circulating fluidized bed. [0003] At present, there are problems in the CFB boiler mixed with petroleum coke: (1) The carbon content of the fly ash is high. It can be seen from the performance t...

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Problems solved by technology

[0003] At present, there are problems in the CFB boiler mixed with petroleum coke: (1) The carbon content of the fly ash is high. It can be seen from the performance test that the carbon content of the fly ash reaches 12% when mixed with petroleum coke; resulting in a decrease in boiler efficiency; Zhenhai in June 2001 After the No. 2 Refining Power Plant blended and burned petroleum coke, due to the high carbon content of the fly ash, it caused secondary combustion at the tail. The accident caused all the economizers and air preheaters to burn out, and the direct economic loss reached 10 million yuan; (2) The maintenance of bed temperature, Petroleum coke is light and fine, with high heat and almost no ash. In order to make it combustible, the bed temperature level should be high. In order to improve the desulfurization efficiency, the bed temperature level should be kept at 870-900°C. Contradictions require adjustments to the fluidization wind speed and combustion conditions in the furnace; (3) In order to effectively desulfurize the boiler, the amount of limestone will increase, and the circulation of limestone in the furnace can reduce the wear of the bed material on the heating surface, but limestone is light, It cannot be completely used as bed material, and the increase of limestone dosage will have a negative impact on boiler combustion, manifested in lowering the melting temperature of bed material, making local coking possible in the boiler; lowering the boiler bed temperature, increasing the carbon content of boiler fly ash

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