Low-odor type reed pulp black liquor combustion boiler and combustion method thereof

Abstract

The invention discloses a low-odor type reed pulp black liquor combustion boiler and a combustion method thereof. The low-odor type reed pulp black liquor combustion boiler comprises a boiler body structure, an air supply structure in a hearth of the boiler body structure comprises a primary air supply duct, a secondary air supply duct and a tertiary air supply duct which are sequentially arranged from bottom to top; air outlets of the primary air supply duct is arranged on the front wall, the rear wall, the left side wall and the right side wall of the hearth; air outlets of the secondary air supply duct is arranged on the front wall and the rear wall of the hearth; air outlets of the tertiary air supply duct is arranged on the front wall and the rear wall of the hearth; and air inlet sections of the primary air supply duct and the secondary air supply duct are connected with an air preheater. Secondary air is fed in from the front wall and the rear wall alternatively, thus being beneficial to full mixing of air and smoke as well as black liquor particles, disturbing rising smoke, improving the turbulivity, enhancing the combustion, enabling the smoke to be uniformly distributed in the hearth, and improving the consistency of temperature field equal-altitude sections.

Description

technical field [0001] The invention belongs to reed pulp black liquor treatment technology, and in particular relates to a black liquor combustion boiler technology for an alkali recovery system in the pulp and paper industry. Background technique [0002] Compared with wood pulp black liquor, reed pulp black liquor has higher moisture content (about 50% water content), lower calorific value, lower expansion degree, and higher viscosity, and is more difficult to burn than wood pulp black liquor. It is designed directly by referring to the wood pulp black liquor boiler, and a disc evaporator is arranged at the tail of the boiler to increase the concentration of the black liquor entering the furnace. [0003] The secondary air distribution of these reed pulp black liquor boilers is arranged on four walls, and the tertiary air is arranged on the left and right walls or front and rear walls. This arrangement is easy to form a "channel flow" in the center of the furnace, and the...

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Problems solved by technology

[0003] The secondary air distribution of these reed pulp black liquor boilers is arranged on four walls, and the tertiary air is arranged on the left and right walls or front and rear walls. This arrangement is easy to form a "channel flow" in the center of the furnace, and the air and black liquor are not fully mixed. Insufficient combustion of black liquor, the high temperature zone of the furnace moves upwards, resulting in over-burning of the upper heating surface of the furnace and serious ash in the heated area of ​​the tail, which seriously affects the boiler efficiency and continuous operation cycle; the process steam in the factory is generally 0.5MPa and 1.0MPa. The temperature of the combustion-supporting air of the boiler will not exceed 180°C after being heated by the above-mentioned steam, and the temperature of the combustion-supporting air is low, resulting in unstable combustion of the black liquor and difficulty in adjusting the load of the boiler; a large amount of flue gas is likely to be generated when the black liquor is heated by the disc evaporator polluting odor

Existing reed pulp black liquor boilers generally have problems such as unstable black liquor combustion, low combustion efficiency, serious boiler ash accumulation, short operating cycle, and secondary pollution odors.

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