The bio oil has high energy content and could be used to replace fossil fuel for process heating.
The easiest modification would be to the stove. If some sort of mineral wool wick was used to pre-heat an additional feed tube to the burner, then one could quite probably use the bio oil directly. Of course, if one made bio-diesel, you could use it for both cooking and fuel.
Bio oils cannot be directly used in existing kerosene stoves as bio oils possess comparatively lower percolation capacity due to higher viscosity.
So other two options possible are
1. Kerosene - bio oil blend
The Energy and Research Institute (TERI - India) has conducted studies on kerosene-bio oil blends to replace kerosene in stoves. A combination of pongemia oil (Pongamia pinnata plant seed oil) and kerosene was tested with varying amount of kerosene, i.e 90% kerosene, 85% kerosene, 80% kerosene and pure pongemia oil. The tests were carried out both in the pressurised (offset burner type) and wick stoves. The results showed that a blend of 20% pongemia oil with 80% kerosene worked well in a pressurised stove without any technical modifications.
2. Bio diesel alcohol blend
Previous studies have shown that Bio diesel (Fatty acid methyl ester) derived from vegetable oil via trans esterification process are miscible with alcohols and can be used as regular diesel substitute. So that these option can also be considered for developing alternate fuel by proper blending in order to replace kerosene in existing stoves. Also this option consist of zero fossil fossil fuel which can be considered as a great advantage.
Some of the issues associated with the bio oil are 1) high viscosity, 2) storage instability (forms a gel over time), 3) high acidity, 4) high moisture content, and 5) potentially high inorganics. Items 1-4 are primarily related to the high oxygen content, which could be reduced to lower values via hydrogen reforming. However, this is both expensive and difficult.
An alternative is to make the stove work with oil. If the oil is not stored long, has no corrosion-vulnerable components, and the feed line can be heated to control the viscosity, you probably only need to adjust and frequently clean the jet.
Well put Larry. I cannot emphasize enough the impact of acid (pH 2 to 3) on a brass stove. Even though we are generally talking about weak acids (acetic, formic, propionic), acids will quietly eat away at brass. So, any fuel you use must be neutralised at the very least.
Just an additional comment I have not seen mentioned: you need a certain flashpoint for kerosene stoves to work adequately. If your bio oil does not have this, then ignition and the maintenance of the flame becomes a challenge. Mixing bio fuels with low flashpoint fuels, as mentioned by Sachin, is a way to overcome this. Generally the low flashpoint fuel also reduces viscosity allowing a reasonable atomisation to occur.
Rex, any Idea on the blending ratio between the bio oil and ethanol? a low flash point fuel as you suggested? 50:50 blend doe snot seems to work fine.
Mohammed,
I have no idea and never seen data on this. However, my SWAG (scientific wild ass guess) is that 20% will work very effectively and you could probably get it down to 10% or less. Essentially you want something to burn easily to raise the temperature at the combustion site that will heat the low flashpoint liquid to flashpoint and then you are away.
Some studies have been carried out on replacing regular diesel and kerosene with bio oil ethanol blends. In most of the cases blending up to 30% of ethanol with bio oil have shown acceptable results, also blended fuel properties observed to be matching with diesel and kerosene.
note: If you are looking forward for an efficient and complete replacement of kerosene with bio oil ethanol blends, better find the optimal blend ratio by setting the fuel properties as constraints ( mainly flash point and viscosity, as mentioned by Dr Larry and Rex)
The following articles may be helpful for you.
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.415.5280&rep=rep1&type=pdf
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.415.3643&rep=rep1&type=pdf
Sachin,
Both texts are not quite similar to what is being suggested here. The 30% ethanol blend for compression ignition engines appears to be selected to ameliorate some of the undesirable VGO qualities and not necessarily for ignition. In the second text, the ethanol improves combustion overall thereby improving the post combustion conditions of a kerosene stove. This text does point to the benefit of adding ethanol to a bio oil in that it should improve the post combustion conditions when burnt in a compression kerosene stove. Most kerosene stoves are operated indoors and the post combustion products have a big impact on the quality of life for the folk using them. So one might increase the ethanol content for this purpose if nothing else...
Rex,
The 30% ethanol content is just an approximate value and the links i shared just shows the bio oil-ethanol blends can be used as substitute for kerosene in stoves. These texts points out only the feasibility of bio oil ethanol blends.
And of course i agree with you that the post combustion products produced, when using bio oil can make higher impact on air quality. But it does not mean one can increase the amount of ethanol in blend considerably to reduce emissions alone.
here discussion is on how to improve the fuel properties of bio oil to match that of kerosene for using in existing stoves right.
- In this case for perfectly using bio oil - ethanol blend as kerosene substitute, the optimal blend ratio must be found out by taking into consideration of all the related fuel properties and their corresponding refinery blending rules (formulas)
Dear Alhassan,
It actually depends on the properties of bio oil you have extracted irrespective of its feedstock. For Kerosene stove applications, oils must have reduced viscosity but improvised thermal properties. So you can try anyone of the following methods which help you reducing the viscosity to greater extent but thermal properties to marginal extent:
(i) try distillating the bio-oil and capture the volatile vapours, condense it.
(ii) try using ultrasonic assisted or microwave assisted breaking
(iii) else as suggested try chocoholic blends
Hope this helps you.All the very best Sir
Regards,
Goku
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