Reduction of Methane Slip from Marine Gas Engines by Oxygen Stratification using Gas Permeation Membrane

2014 Fiscal Year Final Research Report

• Project/Area Number: 24246144
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Naval and maritime engineering
• Research Institution: Kyushu University
• Principal Investigator: TASHIMA Hiroshi 九州大学, 総合理工学研究科(研究院), 准教授 (70179688)
• Co-Investigator(Kenkyū-buntansha): TAKASAKI Koji 九州大学, 総合理工学研究院, 教授 (30154769) ; TSURU Daisuke 九州大学, 総合理工学研究院, 助教 (10614620)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: ガスエンジン / 気体分離膜 / メタンスリップ / 天然ガス / 窒素酸化物 / ノッキング

Outline of Final Research Achievements

Gas engines are expected as strong substitutes for marine diesel engines, but premixed lean-burn gas engines suffer two massive flaws. One is abnormal combustion called knocking and the other is methane slip. This research proposes a novel reducing method of the methane slip through usage of a gas permeation membrane (GPM). The GPM forms stratified oxygen gradient inside a combustion chamber. O2-rich premixture biased toward a cylinder wall decreases a quenching distance and N2-rich premixture around a cylinder center controls knock tendency and NOx emission.
Following issues were numerically investigated, feasibility of a twin turbo-charging system, possibility of oxygen stratification during compression, and potential of the methane slip reduction on chemical analysis. Finally, combustion tests were done using a constant-volume chamber and a rapid compression-expansion machine, and the system was found to compromise the knock avoidance and the methane slip reduction effectively.

Free Research Field

熱機関工学，熱力学，舶用工学，燃焼工学