What is the significance of low steam generator flue gas exhaust temperature?

The low flue gas exhaust temperature of the steam generator has many important significances, mainly reflected in the following aspects:

Improve thermal efficiency and reduce energy waste: Generally speaking, the thermal efficiency can be increased by about 1% for every 10℃ reduction in flue gas exhaust temperature. This is because the lower flue gas exhaust temperature reduces the heat loss carried away by the flue gas, allowing more heat to be transferred to the water, thereby generating more steam, improving energy utilization, reducing fuel consumption, and saving operating costs for the enterprise.Reduce equipment loss: High-temperature flue gas will cause greater thermal stress and corrosion to the exhaust pipe and related components of the steam generator. Lower flue gas exhaust temperature can reduce the heat load of these components, reduce thermal stress, and reduce deformation and damage of metal materials. At the same time, it can also slow down the corrosion rate of acidic substances in condensed water on equipment, extend the service life of equipment, and reduce the cost of equipment maintenance and replacement.

However, the flue gas exhaust temperature cannot be too low.

When the flue gas exhaust temperature is too low, the water vapor in the flue gas will condense into liquid water, which will combine with the acidic gas in the flue gas to form corrosive acid liquid, which will cause serious corrosion to the exhaust pipes, heat exchangers and other metal parts of the steam generator, shorten the service life of the equipment, increase maintenance costs and downtime risks.

During the combustion process of fuel, especially sulfur-containing fuels (such as coal, heavy oil, etc.), sulfur dioxide (SO₂) and a small amount of sulfur trioxide (SO₃) will be produced. When the flue gas exhaust temperature drops to a certain level, the water vapor in the flue gas will react with SO₃ to generate sulfuric acid vapor. When sulfuric acid vapor encounters a metal surface below its dew point temperature, it will condense into sulfuric acid droplets, thereby corroding the heating surface at the tail of the boiler (such as economizer, air preheater, etc.). Low temperature corrosion will cause the metal wall thickness of the heating surface to be thinned and the strength to be reduced. This will not only shorten the service life of the equipment and increase maintenance costs, but may also cause safety accidents. For example, leakage due to corrosion and perforation of the heating surface tubes will cause the boiler to stop operating and affect production.The flue gas exhaust temperature of the Composite chamber micro-superheated steam generator（D class）is stably below 50°C. This outstanding performance makes it show significant advantages in the field of energy conservation and environmental protection. On the one hand, its thermal efficiency is improved to the industry-leading level, which can significantly reduce fuel costs compared with traditional steam equipment; on the other hand, it effectively reduces the thermal pollution caused by high-temperature exhaust to the surrounding environment, and significantly reduces the risk of acid gas condensation corrosion, ensuring the long-term stable operation of the exhaust system. In addition, the equipment meets the national requirements for the promotion of high-efficiency and low-emission equipment, providing strong support for enterprises to improve energy utilization efficiency and reduce operating costs, helping enterprises achieve green and low-carbon development goals.