Peningkatan Kinerja Proses Penyulingan Minyak Pala Dengan Metode Uap Langsung

Abstract

Nutmeg oil is one of Indonesian important export commodity. For the last six years (1996-2001), it's price in the word market has showed an inclined increasing. In 1999, the nutmeg oil price reached the average price of 26.18 US dollar/kg. In the beginning of 2000, the average price of Indonesian nutmeg oil in the world market returned to increase and achieved the average price of33.38 US dollar/kg. The market opportunity which is still prospective as well as the raw material availability become the fundamental aspect of the developing the nutmeg oil industry in Indonesia. For the time being, essential oil production existing in Indonesia is small scale industry. The common problem which found, was the long distillation duration which takes 48-52 hours for nutmeg kernel distillation and 72 hours for mace distillation. It caused the high consumption of energy/fuel. The condition was very contradictive to the energy prices which is always increase. In the other side, a sceintific point of view considering the optimum material size as well as the uniform vessel pressure distillation in each small sclae distillation factory is not yet being under attention. The objective of this work is to improve the performance of nutmeg oil distillation process by reducing the duration of distillation process. The specific objective is to find out the effect of material size and vessel pressure to the yield and quality of resulted nutmeg oil from the young nutmeg kernel and mace using direct steam distillation method. The size of nutmeg kernel observed in the experiment was categoried in fine, which was the output of 0.3 cm strainer hole diameter mill; semi rough, which was the output of 0.5 cm strainer hole diameter mill; and rough, which was the output of 1.0 cm strainer hole diameter mill. The distillation conducted of a vessel pressure of 0 atm gauge, with a duration of 12 hours. All experiment run was conducted twice. In second experiment stage, the vessel pressure was levelled to 0.5 and 1.0 atm gauge in order to provide a better process condition. This stage was conducted based on the nutmeg kernel size which given the highest yield as the consideration to determine the best atmospheric pressure in the vessel in perspective of resulting the highest nutmeg oil yield and meet the quality standard. All experiment run was conducted twice and with duration 12 hours The average water content of raw material used was 16.84 % (% v/w), while the average oil content of the raw material used was 17.58 % (%v/w, wet basis). The kernel size of 0.5 cm resulted the highest yield of oil compared to the two other kernel size, it has 12.98 % (% v/w, wet basis) or 11.65 % (% w/w, wet basis). As well as distillation rate in a period of two hours. At the end distillation process, the kernel size of 0.5 cm has succeeded to distill the nutmeg oil from the material in amount of 73.83 %. Thus, the kernel size of 0.5 cm was the best yielded material size compared to the two other material size category. Generally, the quality of the resulted oil from the three kernel size category was still meet the Indonesian Nasional Standard of quality. The density taken ITom the three material size category was in range of 0.895-0.898, (+) 13° for the optic rotation, and 1.474 for the refraktive index. The three material size category have the same solubility in alcohol 90 % for I: 1. The kernel size of 0.5 cm has found to have 0.353 % of volatile residue, which was the highest one compared to the two others. The distillation rate will increase as the increase of steam pressure given during the distillation process. The distillation vessel pressure of 1.0 atm gauge resulted the highest yield of oil, which is 15.86 % (%v/w, wet basis) or 14.3 I % (%w/w, wet basis), as well as the average distillation rate, which is 1635.0 ml. After the prcess completed, the vessel pressure of 1.0 atm gauge has succeeded distilling the nutmeg oil in amount of90.22 % of the total oil in the material. Generally, the oil quality resulted ITom the three different pressure category was still in the range of the Indonesian National Standard of Quality. The density resulted by the three different pressure category was in range of 0.898-0.902, the range of (+)8°_(+)13" was found for the optic rotation, and the range of 1.4740-1.4750 was found for the refraktive bias. The alcohol 90 % solubility of the three different vessel pressures was found in 1: 1, the volatile residue was found in range of 0.35-0.46 %.