Refractories in coke oven practice: Coke oven regenerators (the checker brickwork used for heat recovery) are predominantly constructed using which type of refractory brick?

Introduction / Context:
By-product coke ovens use regenerators (checkerwork) to preheat combustion air and fuel, cycling temperatures repeatedly. The refractory selection must handle high temperatures, thermal cycling, and the specific chemical environment found in coke oven operations.

Given Data / Assumptions:

• Regenerators experience sustained high temperatures and reversals.
• Thermal shock resistance and creep at temperature are concerns.
• Options include fireclay and silica refractories, among others.

Concept / Approach:
Silica bricks have high refractoriness and maintain strength at elevated temperatures due to their transformation characteristics. They are traditionally preferred in coke oven walls and regenerators because of their ability to withstand the specific high-temperature cycling and maintain structural integrity. Fireclay bricks have lower refractoriness under load and are more suited to lower temperature duties.

Step-by-Step Solution:
Identify service temperature and cycling typical for coke oven regenerators.Match property requirements to materials: silica bricks excel at high-temperature structural duties in coke ovens.Select silica bricks as the correct choice.

Verification / Alternative check:
Industrial practice and classic refractory texts document extensive use of silica bricks in coke oven batteries and regenerators because of their thermal endurance.

Why Other Options Are Wrong:

• Fireclay: adequate for moderate temperatures, inferior for the most severe coke oven zones.
• Insulating refractories: prioritized for low thermal conductivity, not for primary structural checkerwork at peak temperatures.
• High electrical conductivity refractories: not a relevant selection criterion for this duty.

Common Pitfalls:
Assuming “insulating” is always best; here mechanical and thermal stability at temperature dominate over insulation.

Final Answer:
Silica bricks