Recent trends in vanadium-based SCR catalysts for NOx reduction in industrial applications: stationary sources

Abstract

Vanadium-based catalysts have been used for several decades in ammonia-based selective catalytic reduction (NH3-SCR) processes for reducing NOx emissions from various stationary sources (power plants, chemical plants, incinerators, steel mills, etc.) and mobile sources (large ships, automobiles, etc.). Vanadium-based catalysts containing various vanadium species have a high NOx reduction efficiency at temperatures of 350–400 °C, even if the vanadium species are added in small amounts. However, the strengthening of NOx emission regulations has necessitated the development of catalysts with higher NOx reduction efficiencies. Furthermore, there are several different requirements for the catalysts depending on the target industry and application. In general, the composition of SCR catalyst is determined by the components of the fuel and flue gas for a particular application. It is necessary to optimize the catalyst with regard to the reaction temperature, thermal and chemical durability, shape, and other relevant factors. This review comprehensively analyzes the properties that are required for SCR catalysts in different industries and the development strategies of high-performance and low-temperature vanadium-based catalysts. To analyze the recent research trends, the catalysts employed in power plants, incinerators, as well as cement and steel industries, that emit the highest amount of nitrogen oxides, are presented in detail along with their limitations. The recent developments in catalyst composition, structure, dispersion, and side reaction suppression technology to develop a high-efficiency catalyst are also summarized. As the composition of the vanadium-based catalyst depends mostly on the usage in stationary sources, various promoters and supports that improve the catalyst activity and suppress side reactions, along with the studies on the oxidation state of vanadium, are presented. Furthermore, the research trends related to the nano-dispersion of catalytically active materials using various supports, and controlling the side reactions using the structure of shaped catalysts are summarized. The review concludes with a discussion of the development direction and future prospects for high-efficiency SCR catalysts in different industrial fields.

Research on structural strengthening technology for regenerative denitration catalysts

“…NO x emissions are a global problem, and flue gases emitted from various industrial processes seriously pollute the environment. 1,2 With China's improved flue gas emission standards 3,4 and the strengthening of air pollution regulations, 3 the focus of NO x treatment has shifted to non-electric industries, mainly the steel, cement, and coking industries. The requirements for the denitration of boiler exhaust gases in various industries are becoming increasingly stringent.…”

A critical review on amorphous–crystalline heterostructured electrocatalysts for efficient water splitting

“…The overuse of conventional fossil energy sources, such as coal, oil, and natural gas, has caused massive issues with natural resource depletion, global warming, climate anomalies, and environmental damage, thus threatening the survival and development of human beings. 1,2 The accelerated reduction of fossil fuels and environmental calamities have forced us to pay attention to the development of new, clean, environmentally friendly, costeffective, and sustainable green energy technologies. Green technologies for energy conversion and storage systems, such as water splitting, rechargeable batteries, and fuel cells, are highly sought after to mitigate the problems associated with renewable energy sources or traditional energy scenarios.…”

Effect of Vanadium Oxide Loading for the Simultaneous NO Reduction and Hg0 Oxidation over a V2O5-WO3/TiO2 Catalyst

“…24 This is especially true for V 2 O 5 -WO 3 /TiO 2 (VWT), which exhibits a deNO x efficiency of more than 90% and enhanced durability against sulfur. 25,26 Because of these advantages, this has become the most commonly used catalyst. Many researchers have studied the applicability in the context of simultaneous denitrification and mercury capture technologies.…”

“…Among the commercial SCR catalysts, V-based SCR catalysts have received considerable attention for a long time because of their high activity and excellent selectivity for denitrification (deNO x ) . This is especially true for V 2 O 5 -WO 3 /TiO 2 (VWT), which exhibits a deNO x efficiency of more than 90% and enhanced durability against sulfur. , Because of these advantages, this has become the most commonly used catalyst. Many researchers have studied the applicability in the context of simultaneous denitrification and mercury capture technologies.…”