The regenerator is a critical component of the coke oven system, responsible for preheating air and gas through heat exchange with refractory checker bricks. Given the long-term exposure to exhaust gases, air, and gas circulation under varying pressures, the structural integrity of the regenerator walls is paramount. Any leakage can disrupt the heating system, leading to localized combustion and overheating of the checker bricks and walls.
01 Construction of Regenerator Walls
The primary indicator of regenerator quality is the airtightness of the main wall. To ensure this, the construction begins with the installation of the lower gas injection pipes. During construction, alignment rods should be used every 1-2 layers of gas pipes to correct their position. A double-sided mortar application method is employed to ensure tight and full seams between the pipes, preventing gas leakage.
When constructing the main wall, if gas pipes are found to be misaligned, causing the center distance to shorten and making it impossible to lay the filler bricks, the pipes should be removed and reinstalled rather than hammered into place. This prevents cracks at the joints. The height of the main wall construction should be controlled to avoid leaving gas pipes exposed at the end of a shift, which could lead to damage and cracks.
02 Maintaining the Top Wall Elevation of the Regenerator
The elevation of the top walls of the regenerator must meet two key requirements: consistency with the design height for metal component installation, and a height difference of no more than 3 mm between adjacent walls. This ensures stability during the construction of the flue above the regenerator.
To achieve these standards, strict adherence to guidelines is necessary. Horizontal levels should be checked frequently, and alignment lines should be used to maintain consistency across walls. A reference wall should be constructed first, and its elevation verified with a level. This reference wall serves as a benchmark for other walls. Regular checks and adjustments are essential to maintain uniformity.
03 Construction with Water Glass Mortar
Water glass mortar, with a specific gravity of 1.33-1.34 and a sodium oxide content of 8-10%, is commonly used for the lower sections of the regenerator. This mortar offers good plasticity and slow water loss, but it can cause changes in joint width due to its sensitivity to vibration and pressure.
When using water glass mortar, joint width should be controlled to 5-6 mm, allowing for compression to the design standard. Care must be taken to avoid excessive vibration or impact on the constructed sections. Regular self-inspection is crucial to identify and correct any issues promptly.
04 Construction of refractory Checker Bricks
The quality of checker bricks is vital for the efficient operation of the regenerator. Key requirements include alignment of brick holes to reduce gas flow resistance, cleanliness to prevent blockages, stable laying with proper joint width, and adequate expansion gaps.
Checker bricks can be laid either concurrently with the regenerator walls or after the entire structure is completed and cleaned. For narrower regenerators (less than 310 mm), laying the bricks concurrently is preferred due to the difficulty of post-construction installation. This method allows for better alignment and cleanliness but requires additional steps for protection and cleaning.
The bricks are laid in sections, typically divided by the height of the scaffolding. After completing the first section of the main wall, the surface is cleaned, and the first layer of checker bricks is placed on the gridiron. The bricks are adjusted using long wooden sticks, and the process continues layer by layer. Protective covers are used to prevent debris from entering the brick holes during construction.
The construction and processing of refractory checker bricks in coke oven regenerators require meticulous attention to detail to ensure structural integrity and efficient operation. By adhering to strict construction standards and employing appropriate methods, the quality and longevity of the regenerator can be significantly enhanced, contributing to the overall performance of the coke oven system.
