일체형 PM/NOx 동시저감장치의 최적 설계에 대한 기초 연구 = A Basis Study on the Optimal Design of the Integrated PM/NOx Reduction Device

다국어 초록 (Multilingual Abstract)

Research on exhaust aftertreatment devices to reduce air pollutants and greenhouse gas emissions is being actively conducted. However, in the case of the particulate matters/nitrogen oxides (PM/NOx) simultaneous reduction device for ships, the problem of back pressure on the diesel engine and replacement of the filter carrier is occurring. In this study, for the optimal design of the integrated device that can simultaneously reduce PM/NOx, an appropriate standard was presented by studying the flow inside the device and change in back pressure through the inlet/outlet pressure. Ansys Fluent was used to apply porous media conditions to a diesel particulate filter (DPF) and selective catalytic reduction (SCR) by setting porosity to 30%, 40%, 50%, 60%, and 70%. In addition, the effect on back pressure was analyzed by applying the inlet velocity according to the engine load to 7.4 m/s, 10.3 m/s, 13.1 m/s, and 26.2 m/s as boundary conditions. As a result of a computational fluid dynamics analysis, the rate of change for back pressure by changing the inlet velocity was greater than when inlet temperature was changed, and the maximum rate of change was 27.4 mbar. This was evaluated as a suitable device for ships of 1800kW because the back pressure in all boundary conditions did not exceed the classification standard of 68mbar.

국문 초록 (Abstract)

대기오염물질과 온실가스 배출량을 저감 시키기 위한 배기 후처리 장치에 대한 연구는 활발히 진행 중이지만 그 중 선박용 입자상물질/질소산화물(PM/NOx) 동시저감 장치에서는 엔진에 미치는 배압 및 필터 담체 교체에 대한 문제가 발생하고 있다. 본 연구에서는 PM/NOx를 동시저감 할 수 있는 일체형 장치의 최적 설계를 위해 장치 내부 유동과 입·출구 압력을 통한 배압의 변화를 연구하여 적절한 기준을 제시하였다. Ansys Fluent를 활용하여 디젤미립자필터(DPF) 및 선택적촉매환원법(SCR)에 다공성 매체 조건을 적용하였고 공극률은 30%, 40%, 50%, 60% 및 70%로 설정하였다. 또한, 엔진 부하에 따른 Inlet 속도를 경계 조건으로 7.4m/s, 10.3m/s, 13.1m/s 및 26.2m/s로 적용하여 배압에 미치는 영향을 분석하였다. CFD 분석 결과, 장치의 입구 온도 보다 입구 속도에 따른 배압의 변화율이 크고 최대 변화율은 27.4mbar였다. 그리고 모든 경계 조건에서의 배압이 선급 기준인 68mbar를 초과하지 않았기 때문에 1800kW 선박에 적합한 장치로 평가되었다.

참고문헌 (Reference)

• 1 김종립 ; 오원철 ; 이원주 ; 최재혁, "습식전기집진기를 활용한 입자상 물질 및 황산화물 저감 성능에 관한 실험적 연구" 해양환경안전학회 27 (27): 898-904, 2021
• 2 ICS, "Shipping and world trade: Driving prosperity"
• 3 Yao, J, "Porous medium model in computational fluid dynamics simulation of a honeycombed SCR DeNOx catalyst" 38 (38): 283-290, 2015
• 4 Conway, R, "NOx and PM reduction using combined SCR and DPF technology in heavy duty diesel applications" 2005
• 5 López-De Jesús, Y. M, "NOx and PM reduction from diesel exhaust using vanadia SCRF" 9 (9): 1247-1257, 2016
• 6 Johansen, K, "Multi-catalytic soot filtration in automotive and marine applications" 258 : 2-10, 2015
• 7 Bagi, S, "Investigation into ash from field returned DPF units: Composition, distribution, cleaning ability and DPF performance recovery" 2016
• 8 Faber, J, "IMO GHG 4th STUDY" 2020
• 9 Anenberg, S. C, "Global air quality and health co-benefits of mitigating near-term climate change through methane and black carbon emission controls" 120 (120): 831-839, 2015
• 10 Crippa, M, "Food systems are responsible for a third of global anthropogenic GHG missions" 2 (2): 198-209, 2021
• 11 Park, G, "Flow analysis of PM/NOX aftertreatment system for emergency generator MDPI AG" 2022
• 12 F. Payri, "Experimental–theoretical methodology for determination of inertial pressure drop distribution and pore structure properties in wall-flow diesel particulate filters (DPFs)" Elsevier BV 36 (36): 6731-6744, 2011
• 13 Shin, C. H, "Expansion of the darcyweisbach relation for porous flow analysis, Trans" 41 (41): 229-238, 2017
• 14 Jin, Y, "Development of new high porosity diesel particulate filter for integrated SCR technology/catalyst" 2015
• 15 E. Parthiban, "Development of Diesel Particulate NOx Reduction DPNR System for Simultaneous Reduction of PM and NOx in Diesel Engines" SAE International 2019-2554, 2019
• 16 Fujii, S, "Design optimization of non-catal yzed DPF from viewpoint of back pressure in ash loading state" 2011