Utilization of filter variation and FABA addition in biogas production from palm oil liquid waste to produce electricity

Industrial waste processing is the best step to create a healthy environment. Industrial waste has the potential to be used as biogas, one of which is palm oil liquid waste. Biogas is produced from the fermentation process of palm oil liquid waste with other materials such as sawdust and boiler ash assisted by EM4 as an activiator for bacteria in fermentation. The purpose of this research was to get the best data on the electric power of the variations and replications carried out. Biogas converted to electricity with 3 variations with 3 replication. P1 is 50% biogas and 50% LPG gas filtered using a sulfur filter, P2 is 50% biogas and 50% LPG gas filtered using a boiler scale filter, and P3 is 50% biogas and 50% LPG gas filtered using a combination filter of sulfur and boiler scale. The fermentation process produces biogas of 70,519.167 cm3 at 21 days. The highest average electricity is 242 watts at a sulfur filter, 176 watts at a sulfur and boiler cale filters, and 168,776 watts at a boiler scale filter.


Introduction
Energy is one of the factors related to human life.The use of energy in human life, makes the quantity and quality of energy must be considered.One of the important energy in human life is electricity.The ever-increasing demand for electrical energy is a separate problem for every country, as well as for Indonesia.Human growth that is not followed by the growth of electricity generation causes an electrical energy crisis.This of course requires alternative energy to be a solution to this problem.One of the energies that can be utilized is biogas energy.Biogas can be used to generate electrical energy, besides that biogas is also able to reduce greenhouse gas emissions.Biogas is a gas obtained from anaerobic activity that degrades organic materials, one of which is liquid palm oil waste.Indonesia is one of the largest palm oil exporting countries in the world.The liquid palm oil waste produced can be used to make biogas [1][2][3][4][5].
Palm oil liquid waste is waste that can be used to make biogas.Palm oil liquid waste contains high organic matter.This organic material can be inverted CH 4 , CO 2 , H 2 O, N 2 , O 2 and H 2 as the end result of this decomposition, where methane is the main composition in biogas emissions.The composition of biogas from the fermentation of organic is CH 4 (50-75) %, CO 2 (24-45) %, H 2 O (1-5) %, N 2 (0-0.003)%, O 2 (0.1-0.5) % and H 2 (1-5) % [6].Biogas from palm oil waste requires a process, namely fermentation.In the fermentation process there are 4 stages: hydrolysis, acidogenesis, methanogenesis.In the manufacture of biogas there are several parameters that must be considered, such as temperature and pH of fermentation.The temperature and pH conditions must be maintained, so the biogas process done well.This study carried out several biogas filters before converting them into electricity.This filter is useful for filtering out impurities that can affect the quality of biogas [7,8].Load growth that is not accompanied by an increase in power generation centers causes an electrical energy crisis.Increasing human needs cause industrial growth to increase, which is accompanied by increasing environmental problems.This certainly encourages the development of biogas as a cheap and environmentally friendly energy source.In this research, biogas is converted to electricity in order to expand the benefits of biogas [9].

Materials and tools
The materials needed are palm oil liquid waste, sawdust, boiler ash, boiler ash scale, and sulfur filters.The tools needed are a 200 l drum as a place for biogas formation, a 2 meter PVC hose for biogas flow, a 1*2 meter biogas bag as a biogas reservoir, a faucet for dispensing samples in measuring daily temperature and pH, a K type thermocouple as a temperature meter , a digital pH meter as a pH meter, a digital scale as a biogas mass measurer, a filter as a biogas filter before it is converted to electricity, and a generator as a tool that will be turned on with biogas fuel to see the conversion of biogas to electricity, a multimeter as a voltage and electric current meter, paper and pen to record data, and handphone as a tool for documentation during research.

Method
This research uses the Non Factorial RAL method with 3 variations and 3 replications with C/N 30 conditions for biogas production.Treatment is carried out on the filter.P1 = sulfur filter variation of a mixture of biogas (50%) with LPG gas (50%) P2 = boiler scale filter variation of a mixture of biogas (50%) with LPG gas (50%) P3 = combination variation of sulfur filter with boiler scale filter on a mixture of biogas (50%) with LPG gas (50%) 2.3.Procedure 2.3.1.Sample preparation.Palm liquid waste, boiler ash, and sawdust were prepared according to the specified presentation.The sawdust is dried in the sun and chopped into fine powder in order to accelerate the decomposition of microorganisms.All ingredients are mixed and proceed to the fermentation stage.

Tool Design.
1. Design a digester as a biogas production site.2. Make two taps on the digester wall.The tap is on the bottom side (± 10 cm from the ground) and in the middle of the digester.This faucet is useful for removing material samples to measure the pH of the material with a digital pH meter.3. Put the sensor for temperature measurement using a type K thermocouple and for temperature reading using a digital thermometer at the top of the digester.4. Design a hose and combine it with a drum, the hose functions as a channel for biogas into the plastic.5. Use PE plastic for biogas storage, plastic size 100 cm x 200 cm 6.Put a digital scale under the plastic.This digital scale functions to weigh the mass of biogas.7. Make taps in the pipe, namely input and output taps.The input tap is the tap that is opened when the biogas is channeled to the plastic, and the output tap is the tap that is opened when the biogas contained in the plastic is channeled to the filter.8. Distribute biogas to the generator after filtering.

Material Manufacturing
1. Prepare all the materials needed to make biogas.2. Measure the C/N ratio of liquid palm oil waste in the laboratory.
3. Mix liquid waste as much as ¾ of the digester with a capacity of 200 liters with boiler ash as much as ¾ of the materials used and put the mixture into the digester.

Data collection
1. Measure the pH of material samples every day at 10.00 AM 2. Measure the temperature of the materials every day at 10.00 AM 3. Measure the mass of biogas every day at 10.00 AM 4. Measuring the electrical power produced from biogas that has been distributed to the digester.5. Electric power is seen through voltage and electric current.Voltage and electric current are measured using a multimeter.6.Then, connect the biogas with a hose to see the flame with the help of a match.7. See the color of the fire produced when the fire is burning.8. Carry out overall data analysis.

Fermentation.
The fermentation process lasts for 21 days.This process pays attention to the temperature and pH of stable fermentation so that the process goes well.A good temperature for fermentation is 25-45°C and a pH of 6.5-7.2.There are 4 stages in this fermentation process.That is: Hydrolysis, Acidogenesis, Acetogenesis, Methanogenesis.2.3.6.Filterization.The filtering process is the stage of filtering biogas before it is converted to electricity.This filter is useful for filtering out impurities in the biogas, so it does not reduce the quality of the biogas.

Temperature analysis
The temperature data obtained can be seen in Figure 1.Temperature changes during the fermentation process.The initial temperature of the fermentation was 28°C and increased until the 17th day of fermentation, in this situation the process of methanogenesis occurred, the breakdown of compounds produced in fermentation into methane gas assisted by the bacteria methanococcus, methanobacteria, and methanosarcina.Figure 1 shows that the highest fermentation temperature is 30°C, this proves that the living bacteria are methanogenic bacteria.

Figure 1. Temperatures
Methanogenic bacteria live at temperatures of 25 -40 (mesophilic).At low temperatures (5-25°C) the conversion process is slow.In mesophilic conditions (25-45°C) remodeling is very good, the reformation process is accelerated with increasing temperature [10].Temperatures that are too low and too high will disrupt the bacterial growth process, which will ultimately inhibit biogas production [11].On the 18th day, the fermentation temperature decreased, this was caused by the bacterial metabolic rate decreasing and growth slowing down.This temperature data influences the results of other data, temperature in optimal conditions will produce good and maximum data.

pH analysis
The pH data obtained can be seen in Figure 2.

Figure 2. pH
Shows changes in pH values during the fermentation process.The pH during the fermentation process has decreased every day, this is due to the presence of organic acids produced during fermentation.data on the top pH and bottom pH of the drum show that the bottom pH of the drum is higher than the top pH of the drum, this is due to the FABA contained in the fermented bottom solution in the drum.Methane formation occurs at a relatively narrow pH, namely pH 5.5 -8.5 for matanogenic bacteria.a decrease in pH is also caused because fermentation will produce organic acids, these organic acids are a by-product of the fermentation process by microbes, these acids lower the pH of the medium and this decrease in pH shows that the fermentation that we are doing is running [12].This electrical energy data is influenced by the temperature and pH of fermentation in the formation of biogas.The resulting biogas is filtered and converted into electricity through the use of biogas in a biogas-fueled generator.

electrical data analysis.
The electrical data obtained can be seen in Figure 3.The electric power in this study is the result of multiplying the voltage by the electric current that is generated when the generator is operating, in which the fuel used is LPG (Liquefied Petroleum Gas) with an LPG level of 50% with a biogas mixture of a certain level, namely 50%.The electric power data can be seen in Table 1.The highest electrical power generated by fuel using a sulfur filter is obtained and the lowest electric power is obtained from materials using a boiler scale filter.the fuel mixture that uses a higher sulfur filter produces an average electric power of 242 watts, this is because the components/content contained in the sulfur filter are more complex with a large percentage to filter the impurities present in the mixture.This sulfur filter has a chemical binder that can absorb acid natural gas, where acid natural gas is an impurity gas in biogas.The mixture of materials filtered using a boiler scale filter produces the lowest electrical power with an average of 168.667 watts, this is influenced by the content in the boiler scale which is not as complex as the sulfur filter content.the scale content of the oil palm boiler is SiO 2 67.4%, CaO 1.5422%, MgO 3 024%, Fe 2 O 3 0.0014% and Al 2 O 3 10.9985%,where Al 2 O 3 and Fe 2 O 3 are oxide compounds which become impurities in SiO 2 , therefore the ability of SiO 2 as the main compound to absorb biogas pollutants is reduced [13].The combination of the two filters produced the second largest electric power in this study with an average of 176 watts, this was due to the presence of impurities that inhibited the activity of silica in the boiler scale.

Conclusions
Based on the research conducted, it can be concluded that the better the combination of ingredients in the filter, the better the biogas obtained.The results of this study indicate that the biogas filtered by the sulfur filter is the best data, this is because the combination of the contents contained in the sulfur filter is better.