1.0 Introduction
1.1 Background of the Study
Complication of a process for ethanol dehydration by fractional distillation arrives when the solution is in the vicinity of its azeotropic point (95.6wt% ethanol) where both compounds are not separable by fractional distillation. Azeotropic distillation is to bring ethanol concentration up to an anhydrous level is an energy intensive and required a use of toxic organic entraners such as benzene. As a result anhydrous ethanol is normally produced by distilling the solution until ethanol concentration of about 75 -90wt% is achieved and other techniques are employed after that remove water to a minusel level.
One of the energy efficient techniques widely used for dehydration of ethanol is adsorption and starchy and cellulose biomass are among several adsorbent that have been accepted that ethanol dehydration by adsorption requires less energy than the conventional azeotropic distillation it is also less energy consuming than adsorption using other adsorbent. For example the total energy consumed in dehydration of ethanol using cellulose was reported to be 2,873 kj/kg ethanol while the adsorption using calcium oxide (CaO) was 3,669kj/kg ethanol. Another attractive advantage of using biomass derived adsorbent is that when regeneration is not practical the spent adsorbent could be used as a feed stock for fermentation either for ethanol or biomass production. Deposition of starchy and cellulosic and environmental friendly due to their readily biodegradability.
Ability of starch and cellulose to adsorb water is a result of interaction in form of hydrogen bonding between free hydroxyl groups (-OH) on their glucose units and the water molecules as depicted. Water is by nature more polar than organic compounds such as alcohols. Therefore it interacts with hydroxyl groups of glucose containing adsorbent with higher strength and faster rate. Consequently, aqueous alcohol solution passing through bed of starchy or cellulose material would come out with lower concentration of water in the solution.
1.2 Objectives of the Study
The aim or objectives of the research work on the dehydration of ethanol water solution using activated starch is determined as follows:
- To identify polysaccharide compounds of starch materials which have the ability of adoption due to the removal of water by contact of the adsorbent either with vapor or liquid of ethanol solutions.
- To determine the adsorption of water from liquid solution 85 95%v/v ethanol onto starchy material.
- To determine the complication of a process for ethanol dehydration by the activated starch.
- To determine investigated water and adsorption efficiency of adsorbent prepared by the activated starch.
1.3 Statement of Problems
The problems which arise as a result of high cost of importation and harsh economic situation in the country, it becomes imperative to search for local raw materials to replace the imported ethanol water solution by starch which yield high quality of activated starch which yield high quality of activated starch for the dehydration of ethanol solution.
1.4 Justification
At present, there is no commercial dehydration of ethanol water solution from activated starch in Nigeria. Huge amount of money are being spent to import ethanol for medical, pharmaceutical research and industries. It will be economically useful if government imitate a move towards the direction of dehydration ethanol from our local raw material such as starch.
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