PVDF HIGH PERFORMANCE PLASTICS IN BIOETHANOL PROCESS AND DISTRIBUTION
BIOETHANOL Bioethanol has a number of advantages over conventional fuels. It comes from a renewable resource i.e. crops and not from a finite resource. Another benefit over fossil fuels is the greenhouse gas emissions. Also, blending bioethanol with petrol will help extend the life of diminishing oil supplies and ensure greater fuel security, avoiding heavy reliance on oil producing nations. By encouraging bioethanol’s use, the rural economy would also receive a boost from growing the necessary crops. Bioethanol is also biodegradable and far less toxic that fossil fuels. In addition, by using bioethanol in older engines can help reduce the amount of carbon monoxide produced by the vehicle thus improving air quality. Another advantage of bioethanol is the ease with which it can be easily integrated into the existing road transport fuel system. Bioethanol is an alcohol made by fermenting the sugar components of plant materials and it is made mostly from sugar and starch crops. With advanced technology being developed, celluosic biomass, such as trees and grasses, are also used as feedstocks for ethanol production. Ethanol can be used in petrol engines as a replacement for gasoline; it can be mixed with gasoline to any percentage. Most existing car petrol engines can run on blends of up to 15% bioethanol with petroleum/gasoline. Ethanol has a smaller energy density than gasoline, which means it takes more fuel (volume and mass) to produce the same amount of work. An advantage of ethanol (CH3CH2OH) is has a higher octane rating than ethanol‐free gasoline available at roadside gas stations which allows an increase of an engines compression ratio for increased thermal efficiency.
Market potensial and co produce chemicals The market potential for bioethanol is not just limited to transport fuel or energy production but has potential to supply the existing chemicals industry. A number of chemicals are produced in the ethanol industry serving a wide range of uses in the pharmaceuticals, cosmetics, beverages, and medical sectors as well as for industrial uses. Co‐produce the following chemicals along with fuel ethanol : 1. Acetaldehyde (raw material for ether chemicals e.g. binding agent for paints and dyes) 2. Acetic acid (raw material for plastics, bleaching agent, preservation) 3. Ethyl acetate (paints, dyes, plastics, and rubber) 4. Ethanol 95 % (foods, pharmaceuticals, fuel ethanol, detergents) 5. Thermol (cold medium for refrigeration units and heat pumps) 6. Ethyl alcohol (spirits industry, cosmetics, print colours and varnish 7. Isopropyl alcohol (IPA) (cleaning agent for electronic device, solvents) INTRODUCTION TO BIOETHANOL PRODUCTION UNIT Ethanol is produced from biomass by hydrolysis and sugar fermentation processes. • Biomass is pretreated with acid and enzyme to produce sugar. • Sugar is then fermented into ethanol. • Ethanol produced contains a significant amount of water, which is removed by using the fractional distillation process.
REACTION STEPS1. Hydrolysis reactor: the feedstock is heating (190°C) at high pressure (12.1 atm) with an acid catalyst (H2SO4). Most of the hemicellulose is converted to xylose.2. Saccharification reactor: an enzymatic reaction occurs, which converts most of the cellulose to glucose.3. Fermentation reactor: most of the glucose and the xylose are converted to ethanol and carbon dioxide. Process Flow Diagram of the Process Development UnitDepending on the biomass source the steps generally include :1.Storage 6. CO2 storage and ethanol recapture2.Cane crushing and juice extraction 7. Evaporation3.Dilution 8. Distillation4.Hydrolysis for starch and woody bio 9. Waste water treatment5.Fermentation with yeast and enzim 10.Fuel storage
Material Compatibility Corrosive chemicals can be a large problem for a lot of these plants and storage. It is important to understand that biofuels have significantly different characteristics from petroleum gasoline and diesel. Higher percentage ethanol blended fuels do not have the same compatibility characteristic of conventional fuels when it comes to storage and dispensing. Bioethanol is electrically conductive and that => corrosivity Ethanol blends are subject to “phase separation” which create corrosive condition *) Bioethanol swells some elastomer 100% ‐, hardness and tensile strength may decrease and then suddenly fails catastrophically Water contamination makes bioethanol more aggressive (water facilitates electrical conductivity, water accelerates oxidation, water may contain corrosive contaminants) Bioethanol is more aggressive in acidic condition Bioethanol is a solvent that attacks elastomers (source : UST (under ground storage tank )CONVERSION FOR STORAGE AND DISPENSING OF BIOFUELS www.waterboards.ca.gov) Metallic materials : soft metals such as zinc, brass or alumunium, which are commonly found in conventional fuel storage and dispensing system, are not compatible. *) Picture : phase separation in a steel (80 – 88% ethanol (ethanol‐water phase in bottom of the tank Source : www.waterboards.ca.gov
Ethanol can accelerated corosion in steel system by scouring or loosening deposits on the internal surfaces of the tank and piping. If an area of corrosion exists, the ethanol can accelerate (scour) the corroded area and cause perforation. Soft metals such zinc, brass, copper, lead and alumunium these metals will degrade or corrode which may damage engine‐parts and may result in poor vehicle driveability. Even if parts do not fail, running an ethanol‐fuelled vehicle with contaminated fuel may cause deposits that could eventually harm the engine. Nonmetallic material that degrade when in contact with fuel ethanol include natural rubber, polyurethane, cork gasket material, polyvinylchloride (PVC), polyamides, methyl‐metaacrylates plastics, polyester‐bonded fiberglass laminates.PVDF Compatible plastics material with Bio Fuel • PVDF exhibit low permeation levels to most fuel while still having good dimensional stability and having low weight gain • PVDF are one of the best resins you can use over a wide range of fuels ‐ Nylon physical properties deteriorate and permeation levels become high with high levels of ethanol in fuel ‐ HDPE where performance deteriorates with higher toluene and iso octane concentration • Biofuel is often not stabilized have a larger effect on materials that don’t have as broad of a range of chemical resistance as PVDF resins. PVDF resistance to fuel mixture such as – bio diesel, aromatic hydrocarbons, aliphatic hydrocarbons and alcohols • PVDF have outstanding retention of its physical properties in fuel service and can give extended service life when compare to other materials • PVDF can withstand to high temperature –short term 150°C and continuous to 140°C (length of service depends on contact time and chemical mixture involved)
Study : No change in dimension after immersion No change in weight after immersion at 40⁰C in biodiesel at 40⁰C in biodiesel Graphic : PVDF gain is minimal (<0,1%) in Diesel and Biodiesel fuels for a period of 16 weeks Kynar resins (PVDF) shows excellent resistance to biodiesel blends. PVDF immersed up to 3000 hrs in biodiesel blends at 40°C, have seen no loss of physical properties minimal length change and minimal swelling. PVDF repels diesel, biodiesel and their blends. (Source:fueling containment system www.arkema‐inc.com) Typically plastics materials such as polyethylen will swell in presence of gasoline and diesel. Long‐term exposure results then in a loss of the mechanical resistance of these plastics. Because of these fluoropolimers nature PVDF does not absorb diesel and keep its strength and physical properties.