How cleaner fuels will lead India towards energy independence | Originally, the diesel engine was designed to run on vegetable oil but since petroleum diesel was much cheaper in comparison biodiesel was not considered as an economical choice. The scenario changed when in 2008, the world saw an upsurge in the fuel price. Suddenly, the fluctuations in the prices were so high that there was a need for a sustainable alternative to petroleum fuel and that is when biofuel entered the arena again.
In India, Pune based biodiesel manufacturer and distributor My Eco Energy (MEE) has developed renewable diesel which goes by the brand name ‘Indizel’. The first fuel station was opened recently at Lonikand, Pune and caters to people in Mumbai, Pune and Nashik. Plans are on to open around 500 fuel stations and about 2000-3000 smaller outlets throughout Maharashtra. This article takes a look at how Indizel is manufactured and what makes it different from other fuels.
Indizel is a second generation biofuel also known as advanced biofuels. What separates Indizel from first generation biofuels is the fact that feedstock used in producing it is not food crops. The only time the food crops can act as a feedstock is if they have already fulfilled their food purpose. One of the reasons why it is being produced from wastes of vegetable oil is the fact that they did not want to get into the food vs. fuel controversy at all.
Below is a brief on the steps that it takes to manufacture the fuel:
• Chemical re-esterification: Acid oil, which is a by-product in vegetable oil refining, mainly contains free fatty acids (FFAs) and acylglycerols, and is a material for production of biodiesel fuel.
Acid re-esterification process is done on the FFAs. The chemical re-esterification process has the capability of converting the free fatty acid back to their respective glycerine molecule. This technique involves adding glycerol to the high FFA feedstock and heating it to a temperature of about 200 degree Celsius with or without the catalyst. The glycerol reacts with the FFAs to form monoglycerides, diglycerides and triglycerides. It produces a low FFA feed that can be processed to methyl esters using traditional homogenous base trans-esterification technique.
• Transesterification: The catalyst is dissolved in the alcohol using a standard agitator or mixer. The alcohol/catalyst mix is then charged into a closed reaction vessel and the oil or fat is added. The system from this stage is totally closed to the atmosphere to prevent the loss of alcohol. The reaction mix is kept just above the boiling point of the alcohol (around 160°F) to speed up the reaction and the reaction takes place. Excess alcohol is normally used to ensure total conversion of the fat or oil to its esters.
• Separation: Once the reaction is complete, two major products exist: glycerin and biodiesel. Each has a substantial amount of the excess methanol that was used in the reaction. The reacted mixture is sometimes neutralised at this step, if needed.
• Alcohol removal: Once the glycerin and biodiesel phases have been separated, the excess alcohol in each phase is removed with a flash evaporation process or by distillation. In other systems, the alcohol is removed and the mixture is neutralised before the glycerin and esters have been separated. In either case, the alcohol is recovered using distillation equipment and is re-used.
Methyl ester wash
Once separated from the glycerin, the biodiesel is sometimes purified by washing gently with warm water to remove residual catalyst or soaps, dried, and sent to storage. This is normally the end of the production process resulting in a clear amber-yellow liquid with a viscosity similar to petrodiesel.
Prior to it being used as a commercial fuel, the finished biodiesel is analysed using sophisticated analytical equipment to ensure it meets any required specifications. The transesterification process is the reaction of a triglyceride (fat/oil) with an alcohol to form esters and glycerol. A triglyceride has a glycerine molecule as its base with three long chain fatty acids attached. The characteristics of the fat are determined by the nature of the fatty acids attached to the glycerine. The nature of the fatty acids can in turn affect the characteristics of the biodiesel.
During the esterification process, the triglyceride reacts with alcohol in the presence of a catalyst, usually a strong alkaline like sodium hydroxide. The alcohol reacts with the fatty acids to form the mono-alkyl ester, or biodiesel and crude glycerol. In most of the production, methanol or ethanol is the alcohol used and is base catalysed by either potassium or sodium hydroxide. A common product of the transesterification process is Rape Methyl Ester (RME) produced from raw rapeseed oil reacted with methanol.
The figure below shows the chemical process for methyl ester biodiesel. The reaction between the fat or oil and the alcohol is a reversible reaction and so the alcohol must be added in excess to drive the reaction towards the right and ensure complete conversion.
A successful transesterification reaction is signified by the separation of the ester and glycerol layers after the reaction time. The heavier, co-product, glycerol settles out and may be sold as it is or it may be purified for use in other industries, like pharmaceutical, cosmetics etc.
Indizel has many properties that benefit the environment. The main benefit is that it can be described as ‘carbon neutral’. This means that the fuel produces no net output of carbon in the form of carbon dioxide (CO2). This effect occurs because when the oil crop grows it absorbs the same amount of CO2 as is released when the fuel is combusted. Indizel by My Eco Energy is less toxic than table salt and more biodegradable than sugar meaning spillages represent far less of a risk than fossil diesel spillages.
The fuel has a higher flash point than fossil diesel and hence is safer in the event of a crash. Indizel can ultimately contribute to counteracting the increased levels of carbon dioxide, particulate matters, hydrocarbons, sulphur oxides, nitrogen oxides, carbon monoxide and air toxics trapped in the atmosphere as a result of long-term burning of fossil fuels. Additionally, biodiesel has a positive energy balance. For every unit of energy needed to produce a gallon of biodiesel 4.5 units of energy is gained.
Santosh Verma
Director
My Eco Energy