# Nitrogen Oxide Removal by Coal-Based Activated Carbon for a Marine Diesel Engine  
[PERSON]  
1 College of Marine Engineering, Dalian Maritime University, Dalian 116026, China; [EMAIL_ADDRESS] (Z.W. ); [EMAIL_ADDRESS] (H.K. ); [EMAIL_ADDRESS] (J.Z. ); [EMAIL_ADDRESS] (L.C.) [PERSON]  
1 College of Marine Engineering, Dalian Maritime University, Dalian 116026, China; [EMAIL_ADDRESS] (Z.W. ); [EMAIL_ADDRESS] (H.K. ); [EMAIL_ADDRESS] (J.Z. ); [EMAIL_ADDRESS] (L.C.) [PERSON]  
1 College of Marine Engineering, Dalian Maritime University, Dalian 116026, China; [EMAIL_ADDRESS] (Z.W. ); [EMAIL_ADDRESS] (H.K. ); [EMAIL_ADDRESS] (J.Z. ); [EMAIL_ADDRESS] (L.C.) Zongyuzte Delta Region Institute of Tsinghua University, Zhejiang, Jiaxing 314006, China  
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[PERSON]  
1 College of Marine Engineering, Dalian Maritime University, Dalian 116026, China; [EMAIL_ADDRESS] (Z.W. ); [EMAIL_ADDRESS] (H.K. ); [EMAIL_ADDRESS] (J.Z. ); [EMAIL_ADDRESS] (L.C.) [PERSON]  
1 College of Marine Engineering, Dalian Maritime University, Dalian 116026, China; [EMAIL_ADDRESS] (Z.W. ); [EMAIL_ADDRESS] (H.K. ); [EMAIL_ADDRESS] (J.Z. ); [EMAIL_ADDRESS] (L.C.) [PERSON]  
1 College of Marine Engineering, Dalian Maritime University, Dalian 116026, China; [EMAIL_ADDRESS] (Z.W. ); [EMAIL_ADDRESS] (H.K. ); [EMAIL_ADDRESS] (J.Z. ); [EMAIL_ADDRESS] (L.C.) Zongyuzte Delta Region Institute of Tsinghua University, Zhejiang, Jiaxing 314006, China  
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[PERSON]  
1 College of Marine Engineering, Dalian Maritime University, Dalian 116026, China; [EMAIL_ADDRESS] (Z.W. ); [EMAIL_ADDRESS] (H.K. ); [EMAIL_ADDRESS] (J.Z. ); [EMAIL_ADDRESS] (L.C.) Zongyuzte Delta Region Institute of Tsinghua University, Zhejiang, Jiaxing 314006, China  
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[PERSON]  
1 College of Marine Engineering, Dalian Maritime University, Dalian 116026, China; [EMAIL_ADDRESS] (Z.W. ); [EMAIL_ADDRESS] (H.K. ); [EMAIL_ADDRESS] (J.Z. ); [EMAIL_ADDRESS] (L.C.) 1  
Zongyuz(1) Low-sulfur fuel oil \(\rightarrow\) vanadium-based SCR denitration. This route is simple and effective. However, the fuel cost is expected to rise because of the high price of low-sulfur fuel oil. The fuel supply system and lubrication system of the diesel engine also need to be modified. In addition, the vanadium-based catalyst is expensive and highly toxic. It causes secondary pollution at disposal after the catalyst's life has expired. (2) High-sulfur fuel oil \(\rightarrow\) vanadium-based SCR denitration \(\rightarrow\) wet scrubber desulfurization. The fuel cost is low by this technical route, but the SOx in the exhaust gas may corrote the subsequent SCR denitration reactor. Secondly, the use of high-sulfur fuel may lead to an increase in PM emissions, and the PM often adheres to the catalyst surface, causing a decrease in denitration efficiency and an increase in exhaust back pressure. What is more, sulfur poisoning of the vanadium-based catalyst is a known issue [13]. (3) High-sulfur fuel oil \(\rightarrow\) wet scrubber desulfurization \(\rightarrow\) vanadium-based SCR denitration. This route can avoid the poisoning effect of SOx on the denitration catalyst. However, the temperature of the exhaust gas after wet scrubber desulfurization is generally below 100 \({}^{\circ}\)C, even as low as 50 \({}^{\circ}\)C [14]. The denitration efficiency of vanadium-based catalyst at low temperatures is poor. It needs a heat exchanger to reheat the exhaust gas before the exhaust gas enters the SCR reactor, which makes the system more complicated. The fuel price is the most important factor in the choice of desulfurization technology. However, SCR technology seems indispensable for ship denitration. There are mainly three reactions in SCR denitration, shown as Equations (1)-(3) [11] below. Equation (1) has the slowest reaction rate, also known as the slow SCR reaction. NOx in diesel exhaust is mainly NO and NO\({}_{2}\), of which NO accounts for more than 90%. The reaction activation energy of Equation (2) is lower than that of Equation (3), so the reaction rate of Equation (2) is higher. Equation (2) is also called the fast SCR reaction.