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• A new method for improving combustion in a rotary kiln has been proposed. • Oxygen carrier can transfer oxygen from the active layer to the passive layer. • Lowered the CO emission was observed. • The carbon conversion can be increased in the presence of oxygen carriers. Solid waste (SW) incineration in a rotary kiln (RK) faces great CO fluctuations due to the batch-fired nature, resulting in incomplete SW combustion, which makes its optimization challenging. A method introducing an oxygen carrier (OC) material into the RK has been first proposed to improve SW conversion, lower the CO emission and reduce the fluctuation of emitted CO during the combustion. In this work, manganese and ilmenite ores have been investigated as OCs, and introduced into a lab-scale RK during the combustion of biomass-based SW. Results show that both the introduction of manganese and ilmenite ores have lowered the CO emission and alleviated the fluctuation of emitted CO under reduced oxygen supply. It has been demonstrated that the OC can increase the available oxygen for effective biomass-based SW combustion in the RK since it can continuously transfer lattice oxygen from the active layer to the passive layer with the bed rolling. Besides, the unconverted CO can be burnt more completely and evenly through the gas–solid redox reaction attributed to the reactivity of OCs over CO. In addition, the OCs can also react with the char through a solid–solid reaction at a high temperature over 1073 K. As a result, the carbon conversion can be increased in the presence of OCs. [ABSTRACT FROM AUTHOR]

Highlights: [•] Diesel–propane dual fuel combustion studied on a modern heavy-duty diesel engine (HDDE). [•] Limitations to maximum achievable propane substitutions identified over a range of BMEPs (5–20bar). [•] Systematic analysis of combustion heat release, efficiencies, NO x , smoke, HC, CO emissions. [•] One of the first studies of exhaust particle size distributions with diesel–propane combustion in HDDE. [•] Fueling strategy and diesel injection timing studies performed at 10bar BMEP. [Copyright &y& Elsevier]

Highlights: [•] The effect of the degree of unsaturation of biodiesels on diesel emissions was investigated. [•] Biodiesels resulted in smoke opacity, with an increase in BSFC compared to ULSD. [•] Saturated biodiesel had highest cetane number and lowest adiabatic flame temperature which was good to reduce NO x emission. [•] The cetane number and adiabatic flame temperature appear to be the key properties that determined the emissions. [Copyright &y& Elsevier]

Highlights: [•] This experiment was conducted at various high altitudes. [•] The emissions of CO, THC and PM decreased when using biodiesel at each altitude. [•] Reduction of THC and PM emission caused by biodiesel decreased at higher altitude. [•] Slight decrease of NO X emission of biodiesel were observed at each altitude. [ABSTRACT FROM AUTHOR]

Highlights: [•] CAI combustion is achieved in a 2-stroke poppet valve GDI engine. [•] Gasoline and its mixture with ethanol are used as the fuel on the engine. [•] The effect of ethanol content on operating range, combustion and emissions are analysed. [ABSTRACT FROM AUTHOR]

• Various compositions of syngas in a homogeneous charge compression ignition engine. • Low-calorific syngas can be auto-ignited using high intake temperature. • An increase in H 2 content indicated a fast combustion and an enhanced ignition. • A high CO fraction deteriorated the combustion stability with slow burning. Homogeneous charge compression ignition (HCCI) is a promising combustion concept that can simultaneously achieve high efficiency and low nitrogen oxides (NO x) emissions. Synthesis-gas (syngas)-fueled HCCI engines can be adapted for a wide range of fuel compositions. The aim of this study was to investigate the combustion and emissions of an HCCI engine with various syngas compositions. The baseline syngas contained 30% H 2 , 25% CO, and 45% CO 2 by volume, which provided a low heating value (LHV) of 6.08 MJ/Nm3. The fuel composition varied from hydrogen-rich to lean. It was found that syngas with an LHV of 3.34 MJ/Nm3 could be auto-ignited by implementing intake boosting with sufficient intake heating. The intake temperature required to achieve autoignition was reduced at higher loads. The start of combustion temperature mainly relied on the intake temperature and fueling rate, regardless of the fuel composition. A higher H 2 content in the fuel facilitated fast burning with good combustion stability, even under lean conditions. It was revealed that a higher CO fraction deteriorated the combustion stability on the lean side with slow burning. The gross indicated thermal efficiency (ITE g) increased with an increase in the LHV of the syngas, with an ITE g of 38.1% realized at a low load of 0.3 MPa for the base fuel, while maintaining engine stability. The combustion efficiency was greater than 90% for the fuels examined at a higher fuel rate. The NO x emissions were very low because of the ultra-lean, diluted charge used for HCCI combustion. [ABSTRACT FROM AUTHOR]