Oxygen-enriched combustion boiler waste heat recovery and combustion-supporting gas preheating system

By designing a waste heat recovery system for step-by-step oxygen heating and a combustion gas preheating system in an oxygen-enriched combustion boiler, the problems of large heat exchange temperature difference and underutilization of waste heat are solved, achieving efficient cascade utilization of energy and system energy recovery, and improving the thermal efficiency of the power plant.

CN117646897BActive Publication Date: 2026-06-02HUANENG LANZHOU THERMAL POWER CO LTD +2
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
HUANENG LANZHOU THERMAL POWER CO LTD
Filing Date
2023-11-29
Publication Date
2026-06-02

AI Technical Summary

Technical Problem

Existing oxygen-enriched combustion boilers suffer from problems such as large heat exchange temperature differences, significant heat loss, and underutilization of waste heat during waste heat recovery. Furthermore, they do not fully integrate with the steam-water system for deep energy recovery.

Method used

By designing a waste heat recovery and combustion gas preheating system for an oxygen-enriched combustion boiler, oxygen is heated in stages using exhaust steam cooling water, flue gas condensate, and dried flue gas. By combining the concept of energy level matching, the heat exchange temperature difference is reduced, the energy utilization rate is improved, and the gas preheating system is deeply integrated with the steam-water system to achieve cascaded energy utilization.

Benefits of technology

It effectively reduces the entropy increase in the heat exchange process, improves the waste heat utilization rate, reduces energy loss, increases the turbine output power, and improves the thermal efficiency of the power plant.

✦ Generated by Eureka AI based on patent content.

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Abstract

The application discloses an oxygen-enriched combustion boiler waste heat recovery and combustion-supporting gas preheating system, which mainly comprises a flue gas condenser, three oxygen heaters, a low-pressure heater, a steam extraction heater and the like. Steam turbine exhaust steam condensate enters the flue gas condenser to condense and dry tail flue gas, so that the flue gas waste heat is recycled and utilized. Low-temperature oxygen is sequentially subjected to heat exchange with steam turbine exhaust steam cooling water, flue gas condensate and dry flue gas in the heater, so that the low-grade heat energy is recycled and utilized. The preheated oxygen is mixed with circulating flue gas to form primary and secondary combustion-supporting air, and the heat of high-temperature flue gas and superheated steam is recovered in a low-temperature preheater and a steam extraction superheater, so that the loss is reduced. The system can fully recycle the flue gas waste heat, effectively recycle the low-grade heat energy, reduce the loss in the combustion-supporting gas preheating process, and improve the efficiency of the oxygen-enriched combustion boiler.
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