| dc.description.abstract | Biomass is one of the renewable energy sources. Renewable energy derived from biomass-based fuels will reduce dependence on fossil fuels for energy needs with lower amounts of carbon dioxide. One of the biomass that can be used is rice straw as biomass that can be converted into a fuel substitute.
Bio-char is a blackish solid fuel made from biomass by pyrolysis or combustion with little or no oxygen, this process is strongly influenced by the raw materials used because it can affect the quality of the bio-char such as hardness and other chemical content. Bio-char which is black, easily crushed and resembles coal consists of 85% to 98% carbon the rest is other compounds.
The raw material used in this preliminary plant design is rice straw. The process begins with the preparation of raw materials, rice straw will be cut using a Rotary Cutter into a size of 40 mm. Next, the drying process of rice straw is carried out using a Rotary Dryer with operating conditions at 150°C, the drying results are accommodated in the Hooper. The second stage is the slow pyrolysis process in the Rotary Kiln reactor with operating conditions at a pressure of 1 atm and a temperature of 400°C for 9 minutes, the heat for the reactor is obtained from the Combuster using LNG fuel. In the Rotary Kiln reactor, nitrogen gas is added which functions as a fluidizer and oxygen binder. The output products of the Rotary Kiln reactor are gases (bio-oil and syngas) and solids (bio-char). The reactor output is then flowed to the Cyclone Separator to separate the main product bio-char as the bottom product and bio-oil and syngas as the top product. Then the bio-char product is stored in the bio-char storage warehouse. The next stage is to change the phase of bio-oil from gas to liquid, several temperature decreases are carried out, first bio-oil and syngas enter Heat Exchanger I to reduce the temperature from 400°C to 3000°C, then enter Heat Exchanger II to reduce the temperature from 300°C to 150°C then bio-oil and syngas flowed into the Condenser for a decrease in temperature from 150°C to 70°C, the result of this process is a liquid in the form of bio-oil and water, and so on. Furthermore, the liquid in the form of bio-oil and water and the remaining gas flowed into the Knock Out Drum for separation between gas in the form of CO2, CO, N2 as the top product and liquid in the form of bio-oil as the bottom product. The final stage is the bio-oil obtained will be pumped into Heat Exchanger III to reduce the temperature before being put into the bio-oil storage tank.
Preliminary plant design of bio-char with a capacity of 65,000 tons/year and operating 330 days a year. The location of this plant is planned to be established in Sei Rampah, Serdang Bedagai Regency, North Sumatra Province with an area of 32,850 m2, and the required workforce is 209 people. The planned business entity form is a Limited Liability Company (PT) with a line and staff organization structure under the leadership of a director.
The results of the economic analysis of the Preliminary plant design of bio-char from Rice Straw are as follows:
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Total Capital Investment (CI) = Rp. 373.458.015.005
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Total Cost = Rp. 694.241.110.470
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Total Sales = Rp. 827.339.447.555
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Net Profit = Rp. 93.223.835.959
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Profit Margin (PM) = 11%
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Break Even Point (BEP) = 39%
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Return On Investment (ROI) = 25%
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Pay Out Time (POT) = 4,006 tahun
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Return On Network (RON) = 39%
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Internal Rate of Return (IRR) = 35,48%
From the results of the economic analysis, it can be concluded that the preliminary plant design for the production of bio-char from rice straw by slow pyrolysis process is feasible to be implemented | en_US |
