Regenerators—thermal energy storage chambers used to preheat air or gas by periodic reversal—are standard waste-heat recovery equipment in which of the following high-temperature units?

Introduction / Context:
Regenerators and recuperators are the two principal categories of high-temperature heat-recovery devices. Regenerators store heat in checker bricks during one part of the cycle and release it to incoming cold gas when flows are reversed. Recognizing where regenerators are “textbook standard” helps with plant identification and troubleshooting.

Given Data / Assumptions:

• We are considering typical steel and coke industry units.
• Waste-heat recovery aims to preheat combustion air or process gas.
• Question seeks the most representative unit using classic regenerators.

Concept / Approach:
Cowper stoves (blast furnace stoves) are the archetypal regenerator application: hot blast air for the furnace is heated by cycling combustion products through checkerwork and then switching to pass the cold air through the heated bricks. While by-product coke ovens use regenerator-like chambers in their heating system, blast furnace stoves are the most widely cited and unambiguous answer in standard MCQs. Soaking pits commonly employ recuperators (continuous heat exchange) rather than classic cyclic regenerators.

Step-by-Step Solution:
Identify the unit most definitively associated with regenerators: blast furnace stoves.Recognize that beehive ovens are obsolete and simpler, not classic regenerator systems.Soaking pits: typically recuperators rather than cyclic regenerator layouts.

Verification / Alternative check:
Steelmaking texts describe the hot-blast system and Cowper stoves as regenerator-based by design, with cyclic firing and air heating phases.

Why Other Options Are Wrong:
By-product coke ovens: Though they have heating passages, the canonical example for regenerators is blast furnace stoves.Beehive coke oven: Antiquated, lacks sophisticated heat-recovery design.Soaking pits: Usually recuperative systems, not cyclic regenerators.

Common Pitfalls:

• Assuming any furnace with checker bricks is necessarily a “regenerator” in the classic sense.
• Confusing recuperation (continuous) with regeneration (cyclic flow reversal).

Final Answer:
blast furnace stoves