“…Therefore, since the HP-SCR system output will be connected to the turbocharger turbine, the placement of the SCR system is an important factor. Reactor bypass valve (RBV), reactor seal valve (RSV), reactor throttle valve (RTV), cylinder bypass valve (CBV), and exhaust bypass valve (EBV) used in HP-SCR in ship diesel engines are used in system optimization (Bayramoğlu and Özmen 2021 ). Fig.…”
Various techniques are used to reduce harmful pollutants such as NOX emissions from ships. Selective catalyst reduction (SCR) systems are the most effective technique used to reduce NOX emissions. In this study, the effects of an SCR reactor on NOX emissions and performance in high-pressure selective catalytic reduction (HP-SCR) systems were investigated numerically. In numerical studies, the effects of SCR system diameter, output form, catalyst activation energy, mixing zone length, and location were investigated as parametric, and the most suitable system geometry was determined. The effects of geometric parameters and catalyst type on emission and performance such as NOX reduction, NH3 slip, velocity, and pressure loss were investigated. It was determined that with increasing system diameter, whereas the NOX reduction performance increased depending on exhaust velocity, the pressure drop decreased, and the most suitable system diameter was determined as 780 mm. Furthermore, the obtained results showed that the performance of NOX reduction decreased after 2 × 106 kJ/kmol activation energy, and the most suitable SCR output form was conical geometry. In terms of the environment, this study will contribute to achieving the UN Sustainable Development Goals such as climate action (SDG 13).
“…Therefore, since the HP-SCR system output will be connected to the turbocharger turbine, the placement of the SCR system is an important factor. Reactor bypass valve (RBV), reactor seal valve (RSV), reactor throttle valve (RTV), cylinder bypass valve (CBV), and exhaust bypass valve (EBV) used in HP-SCR in ship diesel engines are used in system optimization (Bayramoğlu and Özmen 2021 ). Fig.…”
Various techniques are used to reduce harmful pollutants such as NOX emissions from ships. Selective catalyst reduction (SCR) systems are the most effective technique used to reduce NOX emissions. In this study, the effects of an SCR reactor on NOX emissions and performance in high-pressure selective catalytic reduction (HP-SCR) systems were investigated numerically. In numerical studies, the effects of SCR system diameter, output form, catalyst activation energy, mixing zone length, and location were investigated as parametric, and the most suitable system geometry was determined. The effects of geometric parameters and catalyst type on emission and performance such as NOX reduction, NH3 slip, velocity, and pressure loss were investigated. It was determined that with increasing system diameter, whereas the NOX reduction performance increased depending on exhaust velocity, the pressure drop decreased, and the most suitable system diameter was determined as 780 mm. Furthermore, the obtained results showed that the performance of NOX reduction decreased after 2 × 106 kJ/kmol activation energy, and the most suitable SCR output form was conical geometry. In terms of the environment, this study will contribute to achieving the UN Sustainable Development Goals such as climate action (SDG 13).
“…This increased the outlet HNCO concentration and affected the NO reduction rate. In addition, a previous study [35] reported that increasing the HNCO concentration led to less conversion to NH 3 products, which directly affected NO emission reduction performance. Other studies have found ways to reduce the NH 3 slip rate, such as installing mixers or perforated pipes/plates and increasing chamber height [49][50][51][52].…”
Section: Performance Comparisonmentioning
confidence: 97%
“…The NO reduction rate and pressure drop, in particular, are important parameters for evaluating SCR systems. NO reduction is the primary purpose of post-treatment systems, and the pressure drop affects combustion and engine performance [35,36]. However, few design studies have compared conventional and redesigned systems to reduce the overall length of DPF and SCR systems for application in small ships.…”
With increasingly stringent emissions legislation, such as that stipulated by the International Maritime Organization, for nitrogen oxide emission reduction in marine diesel engines, the imperative of curtailing nitrogen oxide emissions from marine diesel engines is intensifying. Consequently, the significance of aftertreatment technologies, including diesel particulate filters (DPFs) and selective catalytic reduction (SCR), is poised to grow substantially. In particular, a redesign is required to reduce the size of DPF and SCR systems for application in small ships. In this study, we varied the shape of the filters in DPF and SCR systems, aiming to achieve a distinct flow pattern and enable overall miniaturization. The performance metrics, including the nitric oxide (NO) reduction rate, NH3 slip rate, and pressure drop, of the redesigned models were compared with those of the conventional model. Computational fluid dynamics simulations were used to compare the performance of the redesigned model with that of the conventional model in terms of NO reduction and pressure drop. The redesigned system achieved a NO reduction rate of 6.9% below that of the conventional system, offering additional noteworthy benefits such as a 50% reduction in both pressure and overall length.
“…The main disadvantage of using SCR system on ships is the limited cabin space. Bayramog˘lu et al 21 used a validated CFD model to compare the performance parameters of HP-SCR and LP-SCR systems, while using a new method to determine the optimal length of the catalyst. The HP-SCR system is installed before the diesel turbocharger and is suitable for low-speed marine engines, but it causes an increase in the exhaust back pressure of the main engine, which affects the performance and fuel consumption of the main engine.…”
Pollutants such as nitrogen oxides (NOx), sulfur oxides (SO2), and particulate matter (PM) in ship exhaust have a great impact on human health, environment and climate conditions. Combined selective catalytic reduction technology and dry exhaust gas cleaning technology, a test rig (SCR-DryEGCS system) for WD10C195-15 marine four-stroke high speed diesel engine was established to analyse the removal effect of NOx, SO2, and PM from exhaust gas. The SCR-DryEGCS system removed 89.03%, 99%, and 96% of NOx, SO2, and PM respectively. And also compared with low sulfur oil combined SCR method to verify the feasibility of the SCR-DryEGCS method. It shows that the SCR-DryEGCS system has its own advantages and has a good effect on the removal of NOx, SOx, and PM at the same time.
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