Migration and Emission Characteristics of Ammonia/Ammonium through Flue Gas Cleaning Devices in Coal-Fired Power Plants of China

Abstract

To investigate the up-to-date migration and emission characteristics of NH 3 /NH 4 + in coal-fired power plants (CFPPs) after implementing ultralow emission retrofitting, typical air pollution control devices (APCDs) in CFPPs, including flue gas denitrification, dust collectors, combined wet flue gas desulfurization (WFGD), and wet precipitators are involved in field measurements. The results show that most of the excessive injected and/or unreacted ammonia from the flue gas denitrification system, whether selective catalytic reduction (SCR) or selective noncatalytic reduction (SNCR), is converted into particle-bound NH 4 + (>91%), and the rest (less than 9%) is carried by flue gas in the form of gaseous NH 3 , with a concentration value of 0.15−0.54 mg/(N m 3 ) at the denitrification outlet. When passing through dust collectors, particle-bound NH 4 + concentration decreases substantially along with the removal of particle matter. In WFGD, the dissolution and volatilization effects affect the gaseous ammonia concentration, which decreases when using limestone slurry and a 20% solution of ammonia as a desulfurization agent, while liquid ammonia solution with a high concentration (99.8%) may cause the flue gas NH 3 concentration to increase considerably by 13 times. Particle-bound NH 4 + concentration is mainly influenced by the relative strength of desulfurization slurry scouring and flue gas carrying effects and increases 2.84−116 times through ammonia-based WFGD. Furthermore, emission factors of NH 3 for combinations of APCDs are discussed.

Emission Characteristics of Soluble Ions in Fine Particulates in Limestone–Gypsum Wet Flue Gas Desulfurization System

“…By contrast, the significant increase in the mass percentage of NH 4 + in particles may mean that NH 4 + in particles is not only derived from the entrained desulfurized droplets but also derived from the adsorption and condensation of volatile gaseous NH 3 , indicating that the entrainment and evaporation of slurry droplets and condensation of volatile components were the formation mechanism of the soluble ionic particles. The similar result was obtained from field tests by Liu el al …”

Dynamic Simulation of Integrated Cleaner Production Strategies towards High Quality Development in a Heavily Air-Polluted City in China

“…Optimal technology selection. Currently, the most used desulfurization and denitrification processes are the limestone-gypsum method and selective non-catalytic reduction (SNCR) denitrification technology [51,52], which account for more than 95% of the pollutant removal technologies employed in Tangshan City. However, owing to the problems of single processes and secondary pollution, advanced technologies should be adopted and selected to improve pollutant removal efficiency.…”

Experimental Study on CO2 Capture from Simulated Flue Gas with an Adsorption–Hydration Method

“…3 In China, large amounts of coal are burned in power plants every passing day; untreated flue gas is directly emitted to the atmosphere. 4 Therefore, it is significant to study CO 2 capture from flue gas for reducing the greenhouse effect and preventing the environment from further deterioration.…”

“…As global warming intensifies, the reduction in emissions of greenhouse gases has gained extensive attention. , It is reported that around 64% of the greenhouse effect is caused by anthropogenic carbon dioxide (CO 2 ) emissions, while a third of it is from flue gas emissions in power plants . In China, large amounts of coal are burned in power plants every passing day; untreated flue gas is directly emitted to the atmosphere . Therefore, it is significant to study CO 2 capture from flue gas for reducing the greenhouse effect and preventing the environment from further deterioration.…”