Rust and pollution protection of the rotating regenerative air - heaters of the boilers

Abstract

Relevance: in order to reduce corrosion and pollution of regenerative air-heaters in gas and mazut boilers during the combustion of sulfurous oil or gas fuels, it is common practice to preheat the air supplied to the cold-end packages of the air-heaters. This air preheating is typically achieved using a calorifier unit, which is fed by steam extracted from turbine take-offs.

To minimize boiler efficiency losses and to keep corrosion and pollution levels within permissible limits under conditions of rapidly varying boiler loads, it becomes necessary to regulate the temperature of the preheated air. However, the standard existing layouts for removing heating steam condensate from the calorifier unit do not ensure a reliable hydrodynamic regime for two-phase flow under such conditions. They also fail to prevent steam from entering the condensate-collecting lower chambers.

This paper presents the results of our research on the development and implementation of a patentable automatic control system for regulating the air preheating temperature in the steam calorifier unit of gas-and-mazut boilers. Additionally, it introduces a specially designed device to eliminate hydraulic shocks in the steam condensate removal system and proposes a new flow diagram for the calorifier unit in the TGM-94 gas-and-mazut boiler of a 160 MW power unit.

Aim: to improve the efficiency and reliability of power boiler operation during combined or separate combustion of sulfur-containing fuels, including natural gas and fuel oil.

Methods: theoretical approaches and practical methods of optimizing the operation of power boilers and their automatic control systems under combined combustion of sulfur-containing fuels were used.

Results: the results of studies on the serial implementation of a new technology and an automatic control system for operational parameters in TGМ-94 boilers during combined combustion of natural gas and fuel oil are presented.