Tony Brooks wrote: > --- In [email protected], Kennet Boater <[EMAIL PROTECTED]> wrote: >> >> Thankyou for the advice Tony, I will think about what you have said. >> >> Two quick questions though, what is a "fuel bug" and its effects on > the fuel/engine and where can I get the biocide to treat/cure it. >> >> I would really like to stay with the biodiesel as it is so much > better for the enviroment and this is ONE of the major reasons my > family live afloat. >> >> Many thanks >> Lee, lucy and josh > > I think Ron has given you a fair reply (I have been on holiday)and I > suspect we can add Marine 16 and Fortron. > > I am afraid I would take some issue with your last statement unless > you have cast iron proof that your bio-diesel is all produced from > waste local cooking oil and has never been involved in the "splash & > dash" procedure or imported. > > I am interested in how you think the residual chemicals effect the > environment and also the glycerin that is produced. Thats without the > electricity to heat the process (unless guaranteed to be 100% > renewable) and the water required for washing the waste chemicals out > of the brew. > > I agree that spillages are far less damaging (if at all) but > personally, although I would like to move away from hydrocarbon > diesel, I have yet to be convinced that bio-diesel is better for the > environment over all.
I too suspect that bio-diesel is not so environmentally friendly as some would suggest. As Tony says - what about the by-products? As one who works in the chemical industry, I can tell you what happens to waste... Now typical bio-diesel is veg oil treated with methanol and potassium hydroxide. Veg oil is a collection of compounds called esters (made by joining an organic aicd with an alcohol). The process makes all the various esters turn to methyl esters and liberate all the other alcohols (process called transeserification) The likely waste stream will be... Methanol + potassium hydroxide + water + other alcohols (ethanol, propanol, butanol, glycerine, etc) The key disposal factor will be the amount of water 1. If there is a *lot*, then it could possibly be called a basic aqueous stream. They get mixed (at the waste plant) with waste acid streams to make a neutral mix. That's probably then allowed to settle, and then maybe some minor treatment before dumping in a river. 2. If not too much water, then it's a toxic (contains methanol!) non-halogenated flammable waste and will be burnt. Because of the water content, the amount of useful heat will be poor (heat will be lost to evaporate the water!), so just another CO2 emitter. I would guess that the stream will be No.2 - otherwise there will be an enormous amount of waste to be transported. Other options for the waste 3. If the maker has a full scale bio-treatment plant. Bugs like polar items like methanol and other alcohols, and will eat them up to make CO2... 4. Recover some of the methanol during process (before water added!). Latent heat of methanol is not low, it takes a fair amount of energy to distil it. So what you gain with recovery you lose with energy - and bulk cost of methanol is pence per litre. Ron Jones Process Safety & Development Specialist Don't repeat history, unreported chemical lab/plant near misses at http://www.crhf.org.uk Only two things are certain: The universe and human stupidity; and I'm not certain about the universe. ~ Albert Einstein
