Biogas is one of the alternative energy sources that can be updated and can reduce national energy dependence on fossil energy. Biogas has the main composition namely Methane (CH4), Carbon Dioxide (CO2) and Hydrogen Sulphide (H2S). The CO2 content in biogas is still quite large. This causes the efficiency of heat produced is still low so the quality of biogas is still not optimal. Therefore, it is necessary to absorb CO2 content using an absorber. In the Absorption process using clamshell packing as filling material in the absorber column which serves to expand the sensitivity of biogas with absorbent (NaOH). In this study, the variables studied were the effect of flow rate and NaOH concentration on CO2 reduction in biogas so that the purpose of this study was to obtain the optimum conditions from the effect of flow rate and NaOH concentration on CO2 levels. The results of the analysis and calculations obtained showed that the optimum conditions of the absorption process occurred at the flow rate of 9 liters/min and 2 M NaOH with CO2 absorption of 8.1972 grams. In this study, the variation of the flow rate used was 6,7,8,9 and 10 liters/min and variations in the concentrations of 0.5 M NaOH, 0.1 M, 1.5 M, 2 M and 2.5 M NaOH concentrations of 8.6526 grams of CO2 absorbed. From the laboratory analysis, the rate of CH4 and CO2 in biogas was 58.5% by volume and 27.6% by volume while the content of CH4 and CO2 in biogas after absorption was 66.1% volume and 18.0% volume.

This research conducted to convert plastic bags into liquid fuels to be used as alternative fuels in generators to produce electricity. The purpose was to get the influence of the electrical load (200;400; 600;800; and 1000 watt) and ratio liquid fuel product with gasoline (0:5;1:4;2:3;3:2;4:1;and 5:0) towards performance liquid fuel the result of conversion Polypropylene (PP) and Low-Density Polyethylene (LDPE) plastic waste on the unit prototype plastic waste power plant with design capacity 1 KWH in terms of Specific Fuel Consumption (SFC) value, Torque and effective power generator. Effective power and torque analyzed using tachometer, voltmeter, ampere meter, and stopwatch while SFC calculation of liquid fuel consumption. Analysis of this data using descriptive statistical analysis that is describing collected data after being given treatment during the research, by presenting data in the form of tables, figures, and calculations. The results of the research show that the ratio liquid fuel:gasoline 2:3 with 800 Watt Electrical load produced of engine power, torque, and SFC optimal with results 1.280 Hp, 173.611 Nm, and 0.461 Kg/Hp.hr., with type of Polypropylene plastic, while type of Low Density Polyethylene plastic have the result 1.259 Hp, 170.753 Nm, and 0.536 Kg/Hp.hr., so that by mixing it can save conventional fuel specially gasoline.

Economic growth and population explosion are chronic problems in big cities which trigger an increase in energy consumption in society. The flow of plastic used has been a dilemma for a long time, so there are thoughts on how to turn plastic waste into something that can be useful. One of the polystyrene plastic wastes can be processed into liquid fuel by cracking. In this research, the process of cracking polystyrene plastic had been conducted by a catalytic cracking process using a bentonite catalyst. This research aims to be determined the effect of the percentage of the catalyst on the percentage of product yield and the characteristics resulting from the catalytic cracking of polystyrene plastic waste using a bentonite catalyst. The catalytic cracking process will be carried out in a thermal catalytic reactor where the process takes place at a temperature of 250 o C with a cracking time of 20, 40 and 60 minutes and the weight of catalyst 4, 6 and 8% as polystyrene waste is 250 gr. The analysis carried out on the final product is a GCMS analysis showed the characteristic nearly to a standard gasoline.

The energy crisis in Indonesia is caused by an increase in the need for fuel oil which has increased in the replacement of fossil energy reserves. It’s the time to dependency of the petroleum by developing an alternative energy sources that can be renewable. One of the way to overcome this matter is developing the fuel production such as biodiesel which is made by waste cooking oil. The level of FFA is contained the waste cooking oil is used below 5%, namely 1.945% so that the transesterification process can be directly carried out. This research was conducted to determine the effect and the type of catalysts concentration (NaOH and CaO), ((0.5-2.5%) with 3000 ml of waste cooking oil) on the quality of biodiesel. The results of the study shows the effect and the type of catalysts concentration is affected of the quality of biodiesel is produced. The optimum point is using of NaOH catalyst with the amount of catalyst 1% w/w waste cooking oil is yield 84.65%, density 0.8540 gr/ml, viscosity 5.65 cSt, acid number 0.447 mgKOH/gr, water content 0.048%, point flame 167°C, and calorific value 9757.7096 cal/gr, these values have fulfilled the biodiesel quality standards in accordance with SNI-04-7182-2015. while the optimum point is used of CaO catalyst and the amount of catalyst is 2.5% w/w waste cooking oil is yield 58.57%, density 0.8740 gr / ml, viscosity 5.66 cSt, acid number 0.447 mgKOH / gr, water content 0.040 %, flash point 179.6°C, and heating value 9543.5214 cal/gr.