Mitigation approaches and techniques for combustion power plants flue gas emissions: A comprehensive review

Population growth and urbanization are driving energy demand. Despite the development of renewable energy technologies, most of this demand is still met by fossil fuels. Flue gases are the main air pollutants from combustion power plants. These pollutants include particulate matter (PM), sulfur oxides (SOx), nitrogen oxides (NOx), and carbon oxides (COx). The release of these pollutants has adverse effects on human health and the environment, including serious damage to the human respiratory system, acid rain, climate change, and global warming. In this review, a wide range of conventional and new technologies that have the potential to be used in the combustion power plant sector to manage and reduce flue gas pollutants have been examined. Nowadays, conventional approaches to emissions control and management, which focus primarily on post-combustion techniques, face several challenges despite their widespread use and commendable effectiveness. Therefore, studies that have proposed alternative approaches to achieve improved and more efficient methods are reviewed. The results show that new advances such as novel PM collectors, attaining an efficiency of nearly 100 % for submicron particles, microwave systems, boasting an efficiency of nearly 90 % for NO and over 95 % for SO2, electrochemical systems achieving above 90 % efficiency for NOx reduction, non-thermal plasma processes demonstrating an efficiency close to 90 % for NOx, microalgae-based methods with efficiency ranging from 80 % to 99 % for CO2, and wet scrubbing, exhibit considerable potential in addressing the shortcomings of conventional systems. Furthermore, the integration of hybrid methods, particularly in regions prioritizing environmental concerns over economic considerations, holds promise for enhanced control and removal of flue gas pollutants with superior efficiency.

A review of NOx and SOx emission reduction technologies for marine diesel engines and the potential evaluation of liquefied natural gas fuelled vessels

Due to intensive marine activities and the use of low-quality fuel oils, the marine transport accounts for a considerable part of air pollution in the transportation sector. Although ships provide the convenient transportation, they exhaust a large number of hazardous pollutants, especially nitrogen oxides (NOx) and sulfur oxides (SOx), which have a significant side effect on environment and human health. To alleviate the impact of global shipping on the environment, international maritime organization established the more stringent emission regulations from Tier I to Tier III in order to reduce emissions from ships. As a result, various emission reduction technologies need to be developed in order to meet more stringent regulations in the future and reduce the pollutant emissions. Under this background, it is indispensable to examine the existing emission reduction technologies when exploring another possible method to reduce the pollutant emissions. Based on a significant number of related literatures, it is general to utilize the marine alternative fuels to reduce the pollutant emissions. Especially, liquid natural gas (LNG) is considered to be one of the most promising marine alternative fuels due to its economy and environmentally friendly features. This review thus aims to summarize the different emission reduction technologies of marine diesel engines through three reduction paths of fuel optimization, pre-combustion control and exhaust after-treatment. Furthermore, the utilization of LNG in the marine diesel engines are evaluated comprehensively from three aspects of environmental protection, energy structure and economic benefits. At the end, some suggestions on the future research are given based on the extensive review on the state-of-the-art literature.

Diesel engine exhaust denitration using non-thermal plasma with activated carbon

A diesel engine de-NO_x system combining non-thermal plasma and activated carbon was set up. The de-NO_x efficiency reaches 91.8% and 92.5% for simulated gas and real exhaust gas, respectively. It has good potential to replace vanadium-based SCR.