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.

Urgency of the Biogas Unit in the Palm Oil Mills

In palm oil mills with a big vision, business development is important and always receives special attention. Palm oil mills which generally only produce CPO (crude palm oil) and only a few produce PKO (palm kernel oil). Biomass wastes generated such as empty fruit bunches (EFB), fiber and palm kernel shells (PKS) have great potential to be developed into businesses. In addition, the kernel (palm kernel) which has only been sold to other parties can actually be processed by ownself into a PKO. Even CPO itself can also be developed into various derivative products such as cooking oil, stearin, olein and various other oleochemical products. To process the above material, will always need energy and the availability of energy especially those which become a major obstacle to various business developments in the palm oil mill.

Biogas from POME or palm oil mill effluent is a potential energy source that can be created to support a number of business developments based on the palm oil mill. Liquid waste in the form of POME is generally not utilized and is still a problem for most palm oil mills today. By processing it into biogas, it can then be converted to heat and electricity so that it can be utilized for business development that mentioned above. Under certain conditions the biogas produced can even be upgraded to CBG (Compressed Biomethane Gas) with the use as a substitute for fuel in trucks used in the palm oil industry.

There are two types of biogas reactors being developed at this time, namely by maing then covering the pool with a special rubber material (covered lagoon) and a continous stirred tank reactor (CSTR). Although it requires a wider area, the type of covered lagoon is more widely used because in addition to being simpler it can also accommodate more biogas volume. A palm oil mill using centrifugal oil separator will produce a lot of sludge which increases the COD (Chemical Oxygen Demand) thereby increasing the amount of biogas produced. While palm oil mills use decanters, the sludge will be separated so that the COD is low and so is the biogas product produced.

Biogas Water Absorber

The use of biogas to convert to thermal energy (in external combustion engines such as furnaces and boilers) is simpler than the conversion to electrical energy with a gas engine (typical of internal combustion engine). When biogas is converted into heat, the gas purification process is not even carried out and directly burned in the gas burner, so existing boiler of the palm oil can be used. But when it converted into electricity with a gas engine , the biogas purification process becomes important, because the quality of the gas is very influential on the performance and durability of the gas engine and automatically the electricity product produced. Biogas with a lot of H2S content will be corrosive so as to damage the gas engine unit and biogas with high CO2 content will reduce the calorific value so that the gas engine performance will decrease.