APaper

OnCatalytic Cracking of Vegetable Oils – Alternate Route to Liquid

FuelS.  

Department of Chemical EngineeringCollege of Engineering And Technology, Akola(M.S)-

444004. 

By:-Mr.Syed Tanveer Ahmed, Mr.Nikhil Akhilesh Sinha,

INTRODUCTION:-•Vegetable oils are renewable feedstock for production of biomass• Currently vegetable oils are main feed stock for biodiesel production via trans-esterification process.• The main characteristics of generation of biofuels generation from vegetable oil by cracking operation are:-1. Higher green house gas emission (GHG) reduction in

the complete life cycle in comparison with current biofuels.

2. Non-food biomasses are used as raw materials.3. Bio-fuel production to use existing petroleum

refineries.

•Hydro processing of vegetable oil incorporates hydrotreating that is heteroatom removal such as sulfur and nitrogen and hydrocracking that is saturation and breakage of C–C bonds in order to produce high quality gasoline and diesel.

•The main reason is for not using neat vegetable oil as fuel for its high viscosity (usually in the range of 28-40 nm2/sec) •Remedy:-Transesterification of the oil reduces the viscosity of the oil to a range (usually 4–5 nm2/s) closer to that of petro diesel.

•Several processes:-1. Cracking or pyrolysis, 2. Hydrodeoxygenation can be used to obtain fuels resembling

petrodiesel.•Various researches are going on to produce biofuels which having similar hydro carbon compositions like conventional diesel fuels.•It can be done by catalytic deoxygenation of fatty acids and their derivatives.

Flow chart for transformation of lipid materials (vegetable oil) to products of engine combustion.

Chemical structure

Where the groups R, R' and R" are aliphatic, containing from 7 to 19 carbon atoms, and from 0 to 3 double bonds.

Advantages and disadvantages

•The advantages of vegetable oils as diesel fuel are liquidity, ready availability, renewability, lower sulfur and aromatic content, and biodegradability.

•The main disadvantages of vegetable oils as diesel fuel are higher viscosity, lower volatility, and the reactivity of unsaturated hydrocarbon chains.•Researches says that all vegetable oils are extremely viscous, with viscosities ranging from 10 to 17 times greater diesel engine fuel with 10 to 20 carbon number hydrocarbons.

DEOXYGENATION

A schematic diagram of semi batch reactor used for deoxygenation experiment.

HYDROCRACKING OF VEGETABLE OIL

•The cracking reaction leads to production of gasoline and diesel oil from one reaction.•Using cracking operations viscosity is reduced and improves other additional properties for use as a fuel.•Usually cracking is done under the influence of various catalysts:-HZSM, β-zeolite, nickel, platinum, palladium etc.

Reaction mechanism

Reaction mechanism for conversion of vegetable oil to alkanes.

Schematic diagram of hydrocracking pilot plant.

CONCLUSION •In recent times we are talking about clean energy and clean energy source regarding any process.• In this era fuels from vegetable oils can provide some relief with proper modifications.•Using fuels from vegetable oils are much difficult due to their basic properties. Cracking of vegetable oil using different catalysts gives straight chain hydrocarbon and changes occur in basic properties. •Vegetable oils cracking have been understood from the light of this discussion, but more improvement is required on fuel characteristics so that it can completely substitute petroleum-derived fuels.

REFERENCES