Estimated Increase in POME Biogas Production in Indonesia and Malaysia with the Addition of Biomass Briquettes

 

The important thing that needs to be done to implement a research in a commercial unit is the technical and economic side. A research product that has been tested technically needs to be evaluated on the economic side. This is because in commercial units, the economic aspect is the main consideration for the implementation of a certain technology. A technology implemented with the intention of improving the performance of these commercial units but not providing economic benefits generally will not attract many. Likewise, vice versa. How much economic benefit can be obtained from implementing this technology? Is it worth the effort? These two questions will be considered next.

In the biogas unit (mostly for electricity production) the above rules also apply. And especially the biogas unit in Indonesia and Malaysia as the largest CPO (crude palm oil) producer in the world, the POME biogas unit or palm oil mill liquid waste has been built as a means of overcoming the problem of liquid waste and also energy production, especially electricity. Tens or even hundreds of POME biogas units have been built in Indonesia and Malaysia, but that number is not yet comparable to the number of palm oil mills in Indonesia and Malaysia which has reached thousands. And more specifically, the number of POME biogas units in Indonesia is less or a smaller percentage compared to palm oil mills compared to Malaysia. Why did this happen? For more details, please read here.

And because the commercial end product of the commercial biogas unit is electricity, the price of electricity will greatly affect the operation of the biogas unit. Research conducted at Aarhus University in Denmark shows that biomass briquettes can significantly increase biogas production, that is, every 1 tonne of straw briquettes added has increased biogas production by an average of 400 cubic meters. With a biogas caloric value of around 4500 kcal / m3, each tonne of addition of straw briquettes will increase calories by 1,800,000 kcal in the form of biogas. for more details, please read here. In the case of POME biogas, if empty fruit bunches (EFB) are used as raw material for briquettes, it could be an increase in the biogas product produced. This is because the EFB have undergone a sterilization process (steamming) so that the biomass pores are more open so that the surface area is larger. The briquetting of the EFB will also further expand the surface of the biomass so that the anaerobic fermentation process is more perfect and the biogas product increases.

Assuming the electricity price per kwh in Malaysia from biogas is 0.49 RM (IDR 1,715) and IDR 1000 in Indonesia, with the increase in biogas produced above, Malaysia will be more attractive and profitable. However, this increase in biogas production has also yielded attractive advantages when applied, both in Indonesia and Malaysia. The estimate assuming a biogas reactor capacity of 150,000 tonnes and with the addition of 15,000 tonnes of biomass briquettes (maximum 10% of the reactor volume) has resulted in profits of nearly 27 billion rupiah/Rp (application in Indonesia) and 14 million Malaysian ringgit/RM (application in Malaysia). Under these conditions, it is actually very interesting to implement this research on POME biogas power plants in Indonesia and Malaysia. Apart from reducing solid waste from the palm oil industry, increasing biogas production which is proportional to electricity production will provide attractive benefits for the palm oil industry.

Biogas, a Big Potential That is Still Not Much Glimpsed

The main purpose of processing liquid waste that is rich in organic materials is to get clean water both used again (re-use) and disposed of. Biogas products are produced mainly for processing large-capacity liquid waste. The processing stage consists of two stages namely primary and secondary processing. In primary processing, primary sludge will be produced from clarifier or settling tank. The liquid waste is passed to the clarifier or settling tank and the sludge deposit is produced. While in secondary processing, liquid waste is aerated to stimulate microbial growth. These microbes form a floc and settle into secondary sludge. The sludge or sediment must be treated at that location or transported to another place to be processed or disposed of.

The sludge processing unit usually consists of two or four stages. In sludge processing units, small capacity usually consists of only two stages, while large capacity can consist of a total of four stages. The stages of the process are: thickening, digestion (fermentation), dewatering (drying) and sterilization. In the processing unit, small capacity usually only consists of thickening and dewatering, then sludge is further processed elsewhere. Sterilization is only done when there are rules or orders to do it, so it is not done much. In large capacity processing units, the concentrated sludge is then anaerobically fermented to break down complex compounds with the help of microbes, reduce solid volatile and pathogens in the sludge, and simultaneously reduce the occurrence of foul odors.

The sludge fermentation produces biogas. Biogas production depends on sludge composition, residence time in fermentation equipment / digester, temperature and speed of microbial metabolism, which is carefully controlled. If the amount of biogas produced is only small, it is usually only flared or heated in the digester. Whereas if the amount of biogas produced is quite large, it can be used for cogeneration fuel sources. Electricity can also be produced and can be used for internal and external needs. Heat from electricity production can also be used to maintain the digester temperature so that the fermentation process can be optimal. Other options are used to produce renewable natural gas (RNG). RNG can then be used for a variety of purposes both for industry and households.

Tractor with Biogas Fuel

Potential liquid waste for biogas production is from palm oil mill effluent. As the largest CPO producer in the world, Indonesia as first rank and Malaysia second rank, both of which are estimated to have more than 1500 palm oil mills, so the potential for biogas production is also very large. The processing of wastewater from oil palm mills includes large capacity, because the average palm oil mill has a capacity of 60 tons / hour FFB and produces 700 liters of liquid waste for every ton of FFB processed. The use of biogas can be used for energy sources in the palm oil mill. There are two ways that can be done on this matter, namely biogas is used to fuel the palm oil mill with existing equipment with only a few modifications, especially on the biogas burner. In this way palm kernel shells (PKS) and mesocarp fiber commonly used in energy sources can be reduced or even utilized for others.

Whereas the second method, namely biogas output is purified so that generator fuel (gas engine generator) can be used and electricity is used for the operation of the palm oil mill, while the steam needs for sterilization of palm oil mills can remain with the palm fiber and shell or biogas that is. In addition, if the biogas can be packaged in a tube (such as a 3 kg or 12 kg LPG tube) or tank, the use can be wider. Vehicles used to support the palm oil business can use biogas as fuel. Remote communities around oil palm mills who also often find electricity supply because it is very remote can use the biogas to fuel electricity generators. Various business and industrial activities can be done with the availability of electricity. This means also encouraging economic growth of the community surrounding the palm oil mill. Of course not only economic problems are stretching and developing, but also education, religion, health, and social affairs can also develop together well.