船舶低速双燃料发动机在工作过程中会发生甲烷逃逸现象，以现有的催化剂催化氧化效率结合发动机排放试验数据，通过设计计算及理论分析，研究了机外后处理技术在解决该问题上的可行性，分析了采取电加热和补燃方案后对催化效果的影响。研究发现：现有的催化剂虽有较高的催化效率，但在低速机正常排气温度下，经过加权计算的甲烷逃逸量为1.35 g/（kW•h），不满足设计限值1 g/(kW•h)；采取电加热或补燃方案使催化剂活性得到提高后，低速机甲烷逃逸量会有所降低，采取电机热方案和燃烧器补燃方案均可使加权甲烷排放量降低至0.94 g/(kW•h)。

Methane slip occurs in the working process of marine lowspeed dualfuel engine. Based on the existing catalyst catalytic oxidation efficiency combined with the engine emission test data, this paper studied the feasibility of external postprocessing technology to solve this problem through design calculation and theoretical analysis, and analyzed the influence of electric heating or supplementary combustion schemes on the catalytic results. The results show that although the existing catalysts have high catalytic efficiency, the methane slip amount of 1.35 g/(kW•h) still does not meet the design limit of 1 g/(kW•h) after weighted calculation at the normal exhaust temperature of the lowspeed machine; using electric heating or supplementary combustion scheme to improve the catalyst activity, low speed machine methane slip will be reduced, the adoption of electric heating and supplementary combustion scheme makes the weighted methane emission be reduced to 0.94 g/(kW•h).

TK422