Due to the large amount of diesel fuel demands worldwide and the negative environmental and health impacts of its direct combustion, biodiesel production and consumption have been globally increasing as the best short-term substitute for mineral diesel. However, using edible and non-edible oil feedstocks for biodiesel production has led to several controversial issues including feedstock availability and cost, greenhouse gas (GHG) emission, land use changes (LUC), and fuel vs. food/feed competition. Fortunately, these problems can be effectively overcome using non-crop feedstocks. In this context, waste-oriented oils/fats have been proposed as the excellent options to produce biodiesel by overlooking the trivial collection/recycling costs. In this review article, a comprehensive collection plan followed by an elaborated integrated utilization strategy called “waste oil biodiesel utilization scenario” (WO-BUS) is proposed for Iran in order to achieve cost-effective and eco-friendly production/consumption of biodiesel. WO-BUS is adoptable by the countries with similar situations and infrastructures.

A review on the prospects of sustainable biodiesel production: A global scenario with an emphasis on waste-oil biodiesel utilization

Economics of biodiesel production: Review

Impacts of additives on performance and emission characteristics of diesel engines during steady state operation

A comprehensive review on the environmental impacts of diesel/biodiesel additives

NOx reduction behaviour in copper zeolite catalysts for ammonia SCR systems: A review

Diesel engines have high efficiency, durability, and reliability together with their low-operating cost. These important features make them the most preferred engines especially for heavy-duty vehicles. The interest in diesel engines has risen substantially day by day. In addition to the widespread use of these engines with many advantages, they play an important role in environmental pollution problems worldwide. Diesel engines are considered as one of the largest contributors to environmental pollution caused by exhaust emissions, and they are responsible for several health problems as well. Many policies have been imposed worldwide in recent years to reduce negative effects of diesel engine emissions on human health and environment. Many researches have been carried out on both diesel exhaust pollutant emissions and aftertreatment emission control technologies. In this paper, the emissions from diesel engines and their control systems are reviewed. The four main pollutant emissions from diesel engines (carbon monoxide-CO, hydrocarbons-HC, particulate matter-PM and nitrogen oxides-NOx) and control systems for these emissions (diesel oxidation catalyst, diesel particulate filter and selective catalytic reduction) are discussed. Each type of emissions and control systems is comprehensively examined. At the same time, the legal restrictions on exhaust-gas emissions around the world and the effects of exhaust-gas emissions on human health and environment are explained in this study.

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The pollutant emissions from diesel-engine vehicles and exhaust aftertreatment systems

Hydrogen applications in selective catalytic reduction of NOx emissions from diesel engines

The effects of Fe2O3 based DOC and SCR catalyst on the exhaust emissions of diesel engines

Selective catalytic reduction is an application used to control NOx pollutants in diesel engines. Aqueous urea solution, commercially called AdBlue and obtained by mixing pure water and NH3, is the most commonly used reductant while the V2O5–WO3/TiO2 structure has a widespread use as catalyst in SCR technology. However, the SCR systems included AdBlue and V2O5–WO3/TiO2 structure have low NOx conversion efficiency at low exhaust gas temperatures. The use of hydrocarbons as reductant and catalysts containing silver improves the conversion efficiency of selective catalytic reduction systems at low exhaust temperatures. In this work, selective catalytic reduction of NOx emissions from diesel engines in the presence of hydrocarbons has been studied. While ethanol and biodiesel mixtures were used as hydrocarbons, the Ag–Pt/Al2O3 structure was preferred as the catalyst. Scanning electron microscope and X-ray fluorescence analyses of the catalyst produced by the impregnation method were carried out. In order to determine the NOx conversion efficiency of ethanol–biodiesel mixtures in the selective catalytic reduction system, tests were carried out at different engine loads and different exhaust gas temperatures under actual operating conditions. As a result of the tests carried out, it was concluded that the reductant, which consists of 15% biodiesel and 85% ethanol, has the highest conversion performance.

Selective catalytic reduction of NOx emissions by hydrocarbons over Ag–Pt/Al2O3 catalyst in diesel engine

In this study, performance and exhaust emissions of a diesel engine fueled with Fuel A (60% diesel–30% biodiesel–5% ethanol–5% butanol) and Fuel B (40% diesel–50% biodiesel–5% ethanol–5% butanol) were investigated. The biodiesel produced from trap grease was obtained with an oil separator. Fuel A and Fuel B were tested in a single cylinder, four-stroke diesel engine at full load conditions. Compared with diesel fuel, the performance characteristics of blend fuels slightly deteriorated while the emission characteristics improved significantly. CO and HC emissions decreased by 87.01 and 87.50%, respectively.

Ibrahim Aslan Resitoglu

Papers

The pollutant emissions from diesel-engine vehicles and exhaust aftertreatment systems

Hydrogen applications in selective catalytic reduction of NOx emissions from diesel engines

The effects of Fe2O3 based DOC and SCR catalyst on the exhaust emissions of diesel engines

Selective catalytic reduction of NOx emissions by hydrocarbons over Ag–Pt/Al2O3 catalyst in diesel engine

The Influence of Diesel Fuel-biodiesel-ethanol-butanol Blends on the Performance and Emission Characteristics of a Diesel Engine