Effect of a Plasma Burner on NOx Reduction and Catalyst Regeneration in a Marine SCR System

Abstract

The problem of environmental pollution by the combustion of fossil fuels in diesel engines, to which NOx emission is a dominant culprit, has accelerated global environmental pollution and global and local health problems such as lung disease, cancer, and acid rain. Among various De-NOx technologies, SCR (Selective Catalytic Reduction) systems are known to be the most effective technology for actively responding to environmental regulations set by the IMO (International Maritime Organization) in marine diesel applications. The ammonia mixes with the exhaust gas and reacts with the NOx molecules on the catalyst surface to form harmless N2 and H2O. However, since the denitrification efficiency of NOx can be rapidly changed depending on the operating temperature from 250 °C to 350 °C at 0.1% sur contents of the catalyst used in the SCR, a device capable of controlling the exhaust gas temperature is essential for the normal operation of the catalyst. In addition, when the catalyst is exposed to SOx in a low exhaust gas temperature environment, the catalyst is unable to reduce the oxidation reaction of the catalyst, thereby remarkably lowering the De-NOx efficiency. However, if the exhaust gas temperature is set to a high temperature of 360–410 °C, the poisoned catalyst can be regenerated through a reduction process, so that a burner capable of producing a high temperature condition is essential. In this study, a plasma burner system was applied to control the exhaust gas temperature, improving the De-NOx efficiency from the engine and regenerating catalysts from PM (Particulate Matter), SOOT and ABS (ammonia bisulfate), i.e., catalyst poisoning. Through the burner system, the optimum De-NOx performance was experimentally investigated by controlling the temperature to the operating region of the catalyst, and it was shown that the regeneration efficiency in each high temperature (360/410 °C) environment was about 95% or more as compared with the initial performance. From the results of this study, it can be concluded that this technology can positively contribute to the enhancement of catalyst durability and De-NOx performance.

Evaluation of constraints for investment in NOx emission technologies: case study on Greek bulk carrier owners

“…Another option for ship operators to achieve a reduction of NOx emissions by up to 90% is the use of a selective catalytic reduction (SCR) system (Ammar and Seddiek, 2017). The SCR systems are believed to be the most suitable technology for marine engines to meet IMO TIER III regulations (Jang et al, 2022). SCR systems typically integrate catalysts into ship exhaust systems with urea injection systems and monitoring equipment to optimise NOx reduction.…”

“…Another option for ship operators to achieve a reduction of NOx emissions by up to 90% is the use of a selective catalytic reduction (SCR) system (Ammar and Seddiek, 2017). The SCR systems are believed to be the most suitable technology for marine engines to meet IMO TIER III regulations (Jang et al. , 2022).…”

Mitigation of Ship Emissions: Overview of Recent Trends

“…Installing an SCR unit immediately after a wet scrubber so that the low-sulfur stream does not affect SCR performance is energy-intensive and penalized by the low temperature of the scrubbed gas, unless a waste heat recovery system is installed before the scrubber . SCR systems equipped with plasma burners for particulate and soot removal have also been tested to extend the life of the SCR catalyst . This also results in reduced sludge toxicity in the scrubber section due to the destruction of PAHs .…”

Ambient sunlight-driven high performance chlorinated volatile organic compound oxidation by Cu0.15Mn0.15Ce0.7Ox hollow spheres

“…In addition, to optimize catalysts, the impediment of high temperature is the primary technical difficulty to overcome. 19,20 In this case, introducing sunlight-driven catalysis is an attractive approach to integrate the virtue of renewable energy input in catalytic oxidation. For example, solar-driven photothermal CO 2 methanation using SA Ni/ Y 2 O 3 nanosheets resulted in 90% conversion efficiency and 100% methane selectivity.…”