The research article I have chosen is an experimentalstudy of a diesel engine running on blends of diesel and pentanoli.It has been recognized that non-renewable fossil fuel reserves are constantlyin demand and are becoming exhausted. Additionally, the use of thesenon-renewable fuels generates various environmental problems, the major beingglobal warming.
Countries have shown interest in developing alternative energyresources that are renewable, cost-effective, and clean. Among the variousrenewable energy alternatives, bioalcohols could serve as an appropriateresource for diesel engines. Alcohols such as methanol (CH3OH),ethanol (C2H5OH), propanol (CH7OH), andbutanol (C4H9OH) have been utilized due to the reductionof emissions and use of fossil fuels but have limitations including low cetanenumbers, calorific value, and higher latent heat of evaporation. Thus1-pentanol (C5H11OH), which has better fuelcharacteristics, be produced from natural fermentation of biomass, can beeasily blended with diesel, better cetane number, and latent heat ofevaporation is being investigated as a new type of bioalcohol. For the study,fuel blends of 5% (D95Pen5), 10% (D90Pen10), 20% (D80Pen20), 25% (D75Pen25),and 35% (D65Pen35) by volume of 1-pentanol were added into diesel and testedunder 4 engine loads.
The exhaust emissions were measured with a gas analyzer,returning measurements of hydrocarbons (HC), carbon monoxide (CO), oxygen (O2),and nitrogen oxide (NO). The results were that the blends produced higher COemissions due to the higher latent heat of evaporation of pentanol (exceptD95Pen5), produced higher HC emissions, and increased NOx emissions(except D95Pen5 and D65Pen35). It was concluded that D95Pen5 could be utilizedas an alternative fuel as it decreased exhaust gas temperature, CO and NOxemissions at the expense of increasing HC emissions. AnalysisDiesel engine have become a major topic on air qualitydue to the amount of toxic and harmful emissions they produce. Originally,diesel engines were promoted as a more environmentally friendly alternative topetrol engines; producing a fifth less carbon dioxide (CO2)ii.
Diesel engines use less fuel and more air for the same performance as a petrolengine; on average, diesel engines will emit 120 g-CO2/kilometerwhile 200 g-CO2/kilometer for petroliii.In the United States, although heavy vehicles such as trucks and buses – thatutilize diesel engines – represent only 2% of all motor vehicles, they produceapproximately 20% of all NOx emissions from all sources. The needfor renewable, cleaner, and safe fuel alternative to diesel has become animportant research aspect.
The results of the study are interesting in the factthat overall, there was an increase in emissions due to the nature of pentanol.While pentanol has a number of advantages over other alcohols such as beingeasily blendable with diesel, safe usage in diesel engines without any enginemodifications or additives, and better cetane number and latent heat ofevaporation, it still increased HC, NOx, and CO emissions whencompared to diesel fuel. Other studies have shown pentanol’s potential as afuture generation fuel and additive; for example, it improved the fuel properties(high viscosity and cold flow properties) of diesel-biodiesel blends andreduced NOx emissionsiv.The research points to further investigate the D95Pen5 blend as it decreasedthe exhaust gas temperature, CO and NOx emissions but increased HCemissions. Future implications may point to researching pentanol not as astand-alone blend with diesel, but as an additive fuel to improve fuelproperties.
Butanol has also gained research interest because of its highercetane number and energy density. Similar to pentanol, it is easily blendableand can be produced naturally. Additionally, it is seen to result in areduction of soot and NOx emissionsv.
As such, a future direction that could be studied is optimizing a blend ofdiesel-butanol-pentanol as seen in Li, L., et al. study (2015)4.Personally, I believe the article gives significant results.Pentanol blends are a newer technology and by investigating the potentialfuture of this blend, it may prove to become a better additive compared to thecurrent alcohols of methane, ethane, and butane. While the results have shownthat the blends actually increase the emissions, it is still significantresearch which can be used to further study this blend type – potentially changingthe experimental conditions by using different engine technologies or otheradditives along-side.
Clearly the aim of introducing blends of biofuels isto decrease various harmful emissions and at the same time, give the sameperformance compared to diesel fuel but the results of using blends may not alwaysbe a net positive. As seen with the study, the blends of pentanol actuallyincreased the HC, CO, and NOx emissions compared to the base dieselfuel. While pentanol may be easier to blend with other potential alcohols andis a renewable resource, this is still counterproductive as it generates moreemissions compared to simply using diesel fuel, according to this study. Thistrade-off becomes a complex optimization problem: the objective is to decreasethe overall greenhouse gas emissions while implementing as much renewable fuelin a blend as possible without losing vehicle performance. Another factor toconsider in the optimization is the process of producing these alcohols comparedto diesel fuel. Extracting crude oil, to produce diesel fuel, is generally adirty process: involving a lot of wastewater generation and utilization ofhazardous chemicals which cause negative effects on the environmentvi.
Properly treating the wastewater and the processing of crude oil requires theuse of energy, usually fossil fuels, and thus produces another source ofemissions. Similarly, processing biofuels requires the use of energy andproduces emissions: such as through fertilizers, harvesting crops, andprocessing and converting bio-waste. Thus, it is also important to consider andoptimize the entire lifecycle of a renewable fuel compared to the lifecycle ofa fossil fuel to decrease the effect of global warming.
In Canada, the government has imposed a fuelregulation called the Renewable Fuel Regulations. These regulations requirefuel producers and importers to include an average renewable fuel content of 5%and 2% in gasoline and diesel, by volume, respectivelyvii.According to the performance report, GHG emission reductions of approximately7.0 megatonnes (Mt) of CO2 equivalent were accrued in the first twoyears of the Regulations (~3.
7 Mt/year). As of 2017, the Clean Fuel Standard regulatoryframework was developed with the objective to achieve 30 Mt of annualreductions in GHG emissions by 2030viii.Looking specifically at the renewable fuel blends, the short-term decision wasthat the current volumetric requirements be kept the same. In the future, therequired renewable fuel content will most likely be increased in order to reachthe annual reductions goal of 30 Mt. As more blends are developed, the existingrequirements will be raised.
If the government potentially provided furtherincentives, such as lowering taxes on renewable fuel resources, it will help duringfuture industrial practices as a drive to use more renewable fuels in gasolineand diesel content.In conclusion, thestudy points to further research in developing cleaner blends as they are notonly a renewable source, they will produce less GHG emissions and increase theair quality. Additionally, if the vehicle performance is maintained and thefuel is cost-effective, it will drive the industry to shift towards morerenewable sources. With a joint-relationship between the research andregulations: through new updated regulations (as seen with the newest CleanFuel Standard) and ongoing maintenance of the requirements as appropriate, Ibelieve biofuels will have a bright future as a renewable resource.