Parameter analysis on SO₃ measurement in coal-fired flue gas with controlled condensation method

ABSTRACT

The accurate, repeatable, and verifiable measurement of SO₃/H₂SO₄ is significant to the reliability operation of coal-fired power plants, as well as environment protection and human health. Although the amount of SO₃ in flue gas is very small, and its chemical property is extremely active, the measurement of SO₃/H₂SO₄ is difficult and problematic. The measurement errors of controlled condensation method for SO₃/H₂SO₄ in flue gas were evaluated with a sampling system based on dilute sulfuric acid heating method. In order to improve the test accuracy of this method, the effects of water bath temperature, flue gas sampling flow rate, and spiral condensing tube structure parameters (inner diameter and length of spiral condensing tube) on the recovery efficiency of SO₃/H₂SO₄ were investigated. The results indicate that the recovery efficiency fluctuates in the range between 84.1% and 91.6%, with the water bath temperature increasing from 40°C to 90°C. As the flue gas sampling flow rate increases from .5 L/min to 4 L/min, the recovery efficiency of SO₃/H₂SO₄ shows a gradual tendency of increasing, and the recovery efficiency can be high up to 98.4%. When the inner diameter of the spiral condensing tube increases from 3 mm to 10 mm, the recovery efficiency of SO₃/H₂SO₄ decreases gradually. The recovery efficiency of SO₃/H₂SO₄ increases gradually with the spiral condensing tube length increasing from 900 mm to 2000 mm.

KEYWORDS:

• Sulfur trioxide
• Sulfur acid
• acid mist
• controlled condensation method
• coal-fired flue gas

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was funded by the National Key R&D Program of China (No. 2022YFE0206600) and National Natural Science Foundation of China (51606105).

Notes on contributors

Yangjie Qian

Yangjie Qian is currently studying at the School of Energy and Mechanical Engineering, Nanjing Normal University. The research area is emission control technology for flue gas pollutants.

Feihan Chen

Feihan Chen graduated from Nanjing Normal University with a master’s degree in engineering. The research area is emission control technology for flue gas pollutants.

Guiling Xu

Guiling Xu graduated from Southeast University with a Ph.D. in engineering and is currently an associate professor at Nanjing Normal University. The main research directions are area is emission control technology for flue gas pollutants, as well as gas-solid two-phase flow and related numerical simulation research.

Qi Zhang

Qi Zhang graduated from Southeast University with a Ph.D. in engineering and is currently an associate professor at Nanjing Normal University. The main research areas are fluidization theory and application, and emission control technology for flue gas pollutants.

Ping Lu

Ping Lu graduated from Southeast University with a Ph.D. in Engineering and is currently a professor at Nanjing Normal University. The main research directions are the theory and technology of controlling multiple pollutants in flue gas, biomass thermochemical conversion and utilization technology, solid waste energy and resource utilization technology, fluidized bed combustion theory and technology, multiphase flow and numerical simulation.