Absract
The limited oil resources and the tightening of the environmental measures of both the fuels and their combustion products makes it necessary to use alternative types of raw materials for the production of motor fuels, such as bioethanol and other alcohols. This article presents the results of obtaining the diesel fuel with a content of up to 5% watered and dehydrated ethanol. Experiments on the production of diesel-ethanol compositions were carried out at the temperature range of 0–25 ° C with mixing of mixtures using a rotary mixer and an ultrasonic sonotrode with an oscillation frequency of 20 kHz. It was revealed that the stability of diesel-alcohol compositions on using dehydrated ethanol in the composition of diesel fuel to 3% mass. at room temperature is 30 days. The increase of the ethanol content in the diesel fuel composition reduces the stability period of obtained mixture to 25 and 18 days, respectively. For low temperatures, the reduction at the period of stability of the compounds is up to 10 days for 1-2%, 8-5 days for 3-5% compounds, respectively.
On using watered ethanol, even when it is contained in diesel fuel 1% during mixing with an agitator with a turnover rate of 600 rpm, an unstable emulsion forms, which stratifies after a few minutes. The increase of ethanol content in composition of diesel fuel leads to the formation of an even less stable emulsion. However, on mixing the obtained compounds using an ultrasonic sonotrode, slightly coalescing mixtures are formed, the stability of which is no more than 10 days at room temperature and 5 days at low temperature.
Using the method of dynamic light scattering, the dynamics of changes in the size of droplets of watered ethanol in diesel fuel composition with time was investigated and it was established that on the day of preparation of compositions the size of ethanol drops in diesel fuel composition for 3% compound at room temperature is 150-160 nm. On the 5th day after preparation of the compound, the particle size of ethanol increases to 800-900 nm, after which there is a rapid separation of the mixture into diesel and ethanol layers.
To preserve the emulsion of diesel fuel using watered ethanol, an emulsifier obtained on basis of petroleum acids and propylene oxide have been used. Revealed that the addition of it to the composition of the 3% composition of ethanol with diesel fuel ensures the production of homogeneous diesel fuel with retention of all its normalized parameters. The particle size of ethanol in the diesel fuel composition on the day of preparation is 2-7 nm, on the expiry of 20 days the ethanol droplet size increases to 80-90 nm, which ensures the long-term stability of the obtained compound.
It was revealed that, despite the water content of ethanol, the use of this emulsifier ensures the production of homogeneous diesel fuel while retaining all its normalized measures. Reducing the content of carbon monoxide, sulfur oxides and nitrogen in the composition of exhaust gases is 28%, 24% and 16%, respectively.
Keywords : Alternative feedstock, ethanol, emulsifier, exhaust gas composition
Intriduction
Feedstock deficit, unstable world crude and petroleum products prices, and the stringent environmental regulation causes negative effects for the use of mineral energy sources makes it actual of involvement of alternative energy sources and at the same time more environmentally friendly raw materials in the processes of producing commodity fuels such as gasoline and diesel.
Considering the automobile engines provide up to 80% of emissions of toxic substances into the atmosphere (for example, the share of road transport in the emission of harmful substances is 60.6% in the USA, 33.5% in UK, 32% in France, in Moscow and Beijing – 80%, while the annual total emissions of harmful substances by motor vehicles in these cities reach up to 1.7 million tons / year), then one of the priorities for the production of motor fuels is to improve their environmental wellness such as exhaust toxicity rates [1,2]. In the most effective ways, the quality parameters of the mentioned products can be improved by using different oxygen containing additives such as alcohol and ethers (for gasoline and diesel fuel) and alkyl esters of fatty acids (for diesel fuels). The presence of oxygen atoms in these additives provides a more complete combustion of the fuel, which makes the products combustion environmentally safe. The feasibility
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