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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/10065

Title: Design and optimization of lemon grass oil extractor
Authors: Braimah, Soale Rashid
Issue Date: 20-Jan-2017
Abstract: Lemon grass is broadly used in medicine, perfumery industry, vitamin A manufacturing and pharmaceuticals. The need for lemon grass oil, especially in human health and its problem of extracting the oil have directed this thesis to design and optimize a mechanical system that will be used to extract and separate lemon grass oil using direct steam method. The direct steam distillation method eliminates contaminants in the oil and it is environmentally friendly. The steam distillation is carried out under controlled temperature and pressure. In all, three concepts were developed based on the orientation of the condensers, source of power, and method of oil production. The three (3) concepts, Direct Steam Distillation, Hydro Diffusion and Diffuser Diffusion Concepts were evaluated and the best concept, (Direct Steam Distillation), was selected as the final design. Design analyses were performed on each part to determine their specification, the material to be used and manufacturing processes for the fabrication. Lemon oil was extracted from fresh lemon grass that was harvested from a demonstration farm. Two extraction tests were performed, to determine the efficiency and the effect of the operation conditions. Two chemical tests were conducted to determine the quality of the oil and a stress analysis was performed using ANSYS to determine the stresses and deformations on the machine. From the results, it can be established that the prototype machine developed can be used to extract lemon grass oil from the leaves. The efficiencies were computed and the values obtained ranges from 5.87 to 6.33 ml/kg. The results obtained for the quality tests responded positive, a citrus value of 43.56 % was obtained when the pressure was 1.4 bar and the flow rate of 18.5 g/s. The effects of the process parameters on the extraction suggest that, increasing the mass from 20 to 27 Kg results in an increase in the quantity of oil of 39.85 cm3, a decrease of time of 3 minutes, an increase of LPG of 0.41 kg, and a decrease of the quality of the oil of 1.68%. The significant effects and the interactions were used to establish the models of the responses and the process parameters. The predicted model were calculated at each experimental condition and then compared with their measured results. From the results, the predicted (model) results differ from the measured results but it is within the experimental error except one of them which is above the experimental error.
Description: A thesis submitted to The Department of Mechanical Engineering, Kwame Nkrumah University of Science and Technology, KNUST, in partial fulfilment of the requirements for the award of degree of Master of Science, 2016
URI: http://hdl.handle.net/123456789/10065
Appears in Collections:College of Engineering

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