Techno-economic analysis of a small-scale Modified Plant Oil (MPO) production plant that has an annual production capacity of 15,072,741 kg of MPO (batch process) was carried out to estimate the capital and operating ...Techno-economic analysis of a small-scale Modified Plant Oil (MPO) production plant that has an annual production capacity of 15,072,741 kg of MPO (batch process) was carried out to estimate the capital and operating costs of a plant. The analysis was done by using a computer model that was designed and simulated with an aid of SuperPro Designer (Version 4.32) software. The specified feedstock was crude Jatropha oil (JO) and the main product was MPO. The major processes involved were degumming, neutralisation and blending. Degumming involved the removal of gums or phospholipids, and two methods were used: water degumming and acid degumming, whereas blending involved mixing of degummed or purified JO with natural gas condensate (NGC) modifier to lower the viscosity of JO. From techno-economic analysis of the process, it was found that the total capital investment of a plant was about US $ 10,222,000 and the predicted unit production cost of MPO was US $ 1.315/kg at a value of US $ 1.0/kg of JO. The economic feasibility of MPO production was found to be highly influenced by the price of feedstock, which contributed about 95% of the total annual production cost. The relationship between plant throughput and unit cost of producing MPO showed that unit production cost was very sensitive to production rate at low annual throughputs. The MPO cost showed a direct linear relationship with the cost of JO, with a change of US $ 0.50/kg of MPO in MPO cost in every change of US $ 0.50/kg of JO in JO price. The process technology simulated was found to be economically viable and can be implemented in rural setting, taking into consideration Tanzania’s rural situation.展开更多
In this paper, the effect of gangue minerals on the hydrophobic recovery of gold is being investigated using ores obtained from the active small scale gold mining sites in Tanzania. Gold ores of different gangue conte...In this paper, the effect of gangue minerals on the hydrophobic recovery of gold is being investigated using ores obtained from the active small scale gold mining sites in Tanzania. Gold ores of different gangue contents were tested. The effects of silica gangue and high sulphide gangue on gold attachment were examined including the effect of surface activators (potassium amyl xanthate) and the possibility of depressing the effects of gangue using reagents. The results were evaluated in terms of gold recovery, volumes and grade of concentrates formed. There was no change in gold recoveries when the amount of oxide gangue (quartz) in the ore was increased, indicating absence of competition between gold and quartz gangue. High sulphide contents in the ore above 6% reduced gold recoveries considerably. It was noted that potassium amyl xanthate surfactants increased the attachment of both gold and the sulphide gangue. Using lime at pH 10 it was possible to depress the sulphide gangue which is mainly pyrite and hence increased gold recoveries considerably.展开更多
文摘Techno-economic analysis of a small-scale Modified Plant Oil (MPO) production plant that has an annual production capacity of 15,072,741 kg of MPO (batch process) was carried out to estimate the capital and operating costs of a plant. The analysis was done by using a computer model that was designed and simulated with an aid of SuperPro Designer (Version 4.32) software. The specified feedstock was crude Jatropha oil (JO) and the main product was MPO. The major processes involved were degumming, neutralisation and blending. Degumming involved the removal of gums or phospholipids, and two methods were used: water degumming and acid degumming, whereas blending involved mixing of degummed or purified JO with natural gas condensate (NGC) modifier to lower the viscosity of JO. From techno-economic analysis of the process, it was found that the total capital investment of a plant was about US $ 10,222,000 and the predicted unit production cost of MPO was US $ 1.315/kg at a value of US $ 1.0/kg of JO. The economic feasibility of MPO production was found to be highly influenced by the price of feedstock, which contributed about 95% of the total annual production cost. The relationship between plant throughput and unit cost of producing MPO showed that unit production cost was very sensitive to production rate at low annual throughputs. The MPO cost showed a direct linear relationship with the cost of JO, with a change of US $ 0.50/kg of MPO in MPO cost in every change of US $ 0.50/kg of JO in JO price. The process technology simulated was found to be economically viable and can be implemented in rural setting, taking into consideration Tanzania’s rural situation.
文摘In this paper, the effect of gangue minerals on the hydrophobic recovery of gold is being investigated using ores obtained from the active small scale gold mining sites in Tanzania. Gold ores of different gangue contents were tested. The effects of silica gangue and high sulphide gangue on gold attachment were examined including the effect of surface activators (potassium amyl xanthate) and the possibility of depressing the effects of gangue using reagents. The results were evaluated in terms of gold recovery, volumes and grade of concentrates formed. There was no change in gold recoveries when the amount of oxide gangue (quartz) in the ore was increased, indicating absence of competition between gold and quartz gangue. High sulphide contents in the ore above 6% reduced gold recoveries considerably. It was noted that potassium amyl xanthate surfactants increased the attachment of both gold and the sulphide gangue. Using lime at pH 10 it was possible to depress the sulphide gangue which is mainly pyrite and hence increased gold recoveries considerably.
