Computational investigation of ammonia-hydrogen peroxide blends in HCCI engine mode

Abstract

The potential use of hydrogen peroxide as an ignition promoter to enable the use of ammonia in compression ignition engines is explored in the current study. A simplified numerical HCCI engine model within the Chemkin Pro suite is employed. The numerical investigation reveals that the proposed use of hydrogen peroxide is significantly more advantageous against the more conventional method of preheating the intake charge to achieve ignition, whilst using a glow plug. In particular, the IMEP, power and torque exhibit an increase greater than 65% along with a spectacular decrease of NOx emissions reaching in certain cases a 9-fold decrease. The thermal efficiency exhibits a more moderate, yet non-negligible increase, around 5%. Generally, the incremental increase of hydrogen peroxide leads to the increase of the IMEP, power and torque as well as the maximum temperature and, hence, NOx emissions. These increases are largely linear with the hydrogen peroxide addition. Finally, the introduction of hydrogen peroxide leads to a two-stage ignition process, where the first ignition stage was found to be instrumental to the control of the ignition process, and, therefore, the system’s efficiency. Further research is required to substantiate further the feasibility and the the limitations of the proposed technology which can enable the rapid decarbonization of heavy duty applications, such as marine ships and trucks.

Ignition improvers for aqueous ammonia as marine fuel

“…The water present in the aqueous ammonia obviously compounded the problem of cooling the ignition zone with water, making ignition even more difficult than for anhydrous ammonia. 13 In the case of aqueous ammonia with NH 4 NO 2 , the temperature within the ignition Zone 1 dropped initially, but then increased once ignition began. The heat release and expansion of gases in Zone 1 also resulted in an increased of the temperature of the bulk gases in Zone 2, by compression and by heat transfer.…”

“…Shafiq and Efstathios-Al 13 investigated the possibility of reducing ignition delays in a high-speed Homogeneous Charge Compression Ignition (HCCI) engine using hydrogen peroxide (H 2 O 2 ). They found that H 2 O 2 was very effective in increasing engine load and decreasing NOx emissions, when compared with intake air preheating.…”

Computational Investigation of the Influence of Combustion Chamber Characteristics on a Heavy-Duty Ammonia Diesel Dual Fuel Engine

“…In order to take advantage of decarbonized combustion with ammonia, other research has tried to find solutions to improve ammonia combustion. Shafiq and Omar [24] employed hydrogen peroxide as an ignition promoter to facilitate the utilization of ammonia. The results showed a significant increase in indicated engine power and torque, as well as a dramatic reduction in NO x emissions.…”