Palm Oil Mill Operation with Pyrolysis and Biogas Unit Integration for Zero Waste, Maximizing Profits and Sustainability

The goal of a palm oil mill to achieve zero waste, maximum profit, and sustainability can be achieved, among other things, through the integration of pyrolysis and biogas unit. This is because nearly all solid and liquid waste from the palm oil mill can be processed into products needed by the palm oil industry, both in the palm oil mill for CPO (crude palm oil) production and on the palm oil plantation for FFB production. With pyrolysis, solid waste is converted into biochar, producing excess energy in the form of syngas and biooil for boiler fuel. Biochar is first used to increase biogas production before being applied to plantation or agricultural land. 

The biogas product can also be used as fuel for palm oil mill boiler, along with syngas and biooil. This method allows 100% of the palm kernel shell (PKS) to be sold or even exported, thus providing additional profits for the palm oil industry. Currently, 30-50% of the palm kernel shell (PKS) is generally used for boiler fuel, mixed with mesocarp fiber, and the remainder is sold or exported. Biochar production with pyrolysis. The biogas product can also be used as fuel for palm oil mill boiler, along with syngas and biooil. This method allows 100% of the palm kernel shell (PKS) to be sold or even exported, thus providing additional profits for the palm oil industry. Currently, 30-50% of the palm kernel shell (PKS) is generally used for boiler fuel, mixed with mesocarp fiber, and the remainder is sold or exported. Biochar production by pyrolysis can utilize both coconut fiber (MF) and empty fruit bunches (EFB) of palm oil. The integration scheme is as follows:

 

The use of biochar on plantations and agricultural lands will save or reduce the use of chemical fertilizers. This is especially true for oil palm plantations, where the largest operational cost is the use of chemical fertilizers. Reducing chemical fertilizer use will result in savings in fertilizer costs. Furthermore, it will provide other environmental benefits, reducing environmental impacts by minimizing waste from excessive chemical fertilizer use. Biochar slow-releases chemical fertilizers, increasing fertilizer efficiency or Nutrient Use Efficiency (NUE). Furthermore, when combined with biochar and organic fertilizer from biogas residue, the slow-release capacity of chemical fertilizers is further enhanced, resulting in higher NUE. Furthermore, another pyrolysis byproduct, pyroligneous acid (PA), is also highly beneficial for palm oil plantations as a liquid organic fertilizer and biopesticide.

Another source of income is carbon credits, or BCR (biochar carbon removal). Furthermore, carbon credits are currently a strong motivator for producers to produce biochar. To obtain these credits, biochar producers must register with a carbon standards organization and follow their methodology. Some popular carbon standards organizations include Puro Earth, Verra, and CSI. Meanwhile, for biogas production, carbon credits can also be obtained through methane avoidance mechanisms. However, the price of biogas from methane avoidance is usually lower than carbon credits from carbon removal or carbon sequestration with biochar. However, both can be accumulated and yield greater profits.

The operational potential of palm oil mills with integrated pyrolysis and biogas units for zero waste, maximizing profits, and sustainability is enormous and is predicted to become a trend because financial returns align with environmental benefits. Furthermore, environmental and sustainability issues are currently a global concern. With approximately 17 million hectares of palm oil plantations and 5.5 million hectares in Malaysia, the potential for biomass waste, particularly EFB and mesocarp fiber for biochar production, and POME waste for biogas production, is abundant. Globally, palm oil plantations cover nearly 27 million hectares. By 2024, Indonesia will be the world's top CPO producer with 56%, followed by Malaysia with 26%, and Thailand with 5%. There are more than 1,000 palm oil mills in Indonesia and approximately 500 in Malaysia. 

Energy Plantations: Not Only Wood Pellet Production But Must Also Support the Livestock Industry

The concept of energy plantation or biomass plantation by utilizing the whole tree seems to be still unpopular at this time. But sooner or later, God willing, it will happen because profit-oriented wood pellet companies will certainly maximize this aspect or profit, of course as long as it does not damage the environment and CSR (Corporate Social Responsibility) will be pursued in other ways. The main orientation currently focusing on wood products for wood pellet raw materials is certainly a good thing, but it would be much better if the benefits of all parts of the tree could be maximized. If this can be done, the benefits will not only be in the energy sector but also in food and feed, important sectors that are essential in human life.

The main composition of energy plantation leaves such as calliandra and gliricidia is protein and this protein element is an important and most expensive component compared to other elements of animal feed. With a large volume of leaves from energy plantations, it should support the livestock industry and not just be thrown away because it is just a by-product or waste that is less useful. In fact, from the livestock industry side, the opposite is true. The utilization of these leaves can be used directly on livestock or processed into animal feed in a processing industry depending on the local situation and conditions.

Large farms can be made from the utilization of energy plantation leaves as well as animal feed factories from the leaves. Leaf pellet production can be done with a production process similar to wood pellet production so that a wood pellet factory adjacent to a leaf pellet factory is also very possible. Like export-oriented wood pellet products, leaf pellets can also be the same. Meanwhile, if a large farm is to be carried out, waste from the livestock farm or animal waste can be used as raw materials / substrates for biogas production. The biogas can then be used for drying in the production of wood pellets or leaf pellets or used for electricity production. The residue from the biogas will become organic fertilizer, either solid organic fertilizer or liquid organic fertilizer. A simple diagram as below.

Thousands of cattle or breeding cattle are imported into Indonesia from Australia and New Zealand and cattle fattening is a promising business in Indonesia because the need for beef has not been met until now. The shortage of beef is met by importing buffalo meat from India and beef from Brazil. Support for the availability of abundant and quality feed is one of the important aspects of self-sufficiency in this meat. In addition to cattle, the need for goats and sheep is also very large. Yogyakarta, a city that is also famous for its goat satay cuisine, needs more than 1500 heads of sheep per day. In addition, the need for aqiqah and Eid al-Adha is also very large. The sheep export market is also very promising, which until now has not been met due to various factors, one of which is the feed factor. Feed in the livestock business plays a very important role or even around 70% of the cost of livestock is the cost of the feed. And livestock is a link in the chain of food needs for humans so that it is inseparable.

Decarbonization in the Steel Industry

World steel production reached 1.9 billion tons in 2020, with China accounting for around half and followed by European Union countries. Germany, with annual production of around 42 million tonnes, is the largest steel producer in Europe or around a quarter of European steel production, while the other quarter is Italy and France, followed by Belgium, Poland and Spain. The steel industry contributes 8% of CO2 globally, each ton of steel production produces an average of 1.85 tons of CO2 emissions and compared to iron ore mining, iron and steel production contributes much more to CO2 emissions. Efforts to decarbonize the steel industry begin with the use of renewable energy for its smelters. Biomass-based fuel in the form of charcoal which has a high carbon value can replace the use of coke derived from coal. And the use of hydrogen from renewable energy sources is the ultimate target for decarbonization in the steel industry. 

Currently, the steel industry mostly uses coal as fuel using blast furnaces. To reduce carbon intensity, natural gas is used as fuel. The use of gas fuel in the form of natural gas is also a transition medium and basically because it comes from fossil fuels it is also a carbon positive fuel. Apart from that, the use of CNG in the form of natural gas is also a transition fuel before switching to hydrogen from renewable energy. The use of biomass-based carbon fuel in the form of charcoal has a better effect on the climate because it is a carbon neutral fuel. Apart from that, technically, because it is a solid fuel, the same as coal, practically there is not much or even no need for changes or modifications to the smelting furnace. The availability of high quality charcoal, large volumes and continuous supply are still the main obstacles.

The use of charcoal for metallurgy or steel making has actually become commonplace for some time. In the early 1900s, world charcoal production experienced its heyday with production of more than 500 thousand tons. In the 1940s, charcoal production decreased to almost half of what it was in the early 1900s, due to other carbon materials, namely coke from coal, replacing charcoal in the manufacture of metals.

With the current conditions of using coal as the main fuel in smelting furnaces or blast furnaces, slag will be produced. Slag or GGBFS (Grounded Granulated Blast Furnace Slag) from the steel plant is used in cement plants as a cement additive or SCM (supplementary cementious material) thereby reducing the portion of clinker in cement production. In the cement plant itself, the more slag or SCM used, the more clinker use is reduced, thereby also reducing CO2 emissions. In cement production, the clinker production section contributes the most to the CO2 emissions produced, so the use of slag or SCM is part of decarbonization in cement plants. It is estimated that around 70% of world steel production uses the blast furnace or BF-BOF process which produces quite a lot of GGBFS, even in China more than 90% of steel production uses the BF-BOF process. It is worth noting that the decarbonization of the steel sector is resulting in a shift away from blast furnaces, which will impact the availability of GGBFS worldwide in the coming decade. However, this change will occur slowly and gradually and, in the meantime, there are a number of GGBFS that will be available for use as SCM to reduce the carbon footprint of cement and concrete.

To be able to produce charcoal in large quantities, raw materials are also needed in large quantities. Raw materials in the form of biomass, especially wood, can be produced from energy plantations. Energy plantations from fast growing species and short rotation crops will be suitable to meet the need for raw materials because apart from the fast harvest period they also have high productivity. Apart from that, there is no need to replant every time it is harvested and it is easy to grow and easy to maintain. To produce steel per ton, an average of 6,000 MJ of energy is required (equivalent to 50 kg of hydrogen) or the equivalent of 200 kg of charcoal and requires around 600-800 kg of wood biomass as raw material. Apart from raw materials from energy plantation wood, raw materials from agricultural and plantation wastes can also be used.

The future palm oil industry could produce hydrogen from biogas. Each ton of steel will require 50 kg of hydrogen, while each palm oil mill with a capacity of 30 ffb/hour can produce 1 MWh of electricity, while the production of 1 kg of hydrogen requires 50 KWh, so that with the capacity of the palm oil mill it can produce 20 kg of hydrogen. Areas with a high concentration of palm oil mills such as Riau province could create a hydrogen pipeline network for environmentally friendly steel mills.

With higher prices for steel produced with renewable energy (green steel), market share is also limited. Currently, only certain uses, such as automotive, buy such premium or green steel. Decarbonization efforts in steel industries can also be carried out in stages, along with the development of renewable energy. With the increasing supply of renewable energy, the price will decrease so that environmentally friendly steel (green steel) will also become more competitive in price. New steel industries can be built close to these cheap renewable energy sources so that green steel production can become competitive.

Future Palm Oil Mill: Producer of CPO, Biochar and Hydrogen at the Same Time

Efficiency factors, optimizing potential and improving climate should be implemented simultaneously in the palm oil industry. This can be done by replacing the combustion furnace in the boiler with pyrolysis so that the boiler fuel is mainly biooil, a pyrolysis by-product, with the main product being biochar and building a biogas unit for hydrogen production as the final product. Biochar will be used as a soil amendment together with fertilizer so that it becomes slow release fertilizer, so that fertilizer use efficiency (NUE: nutrient use efficiency) increases. The use of biochar as carbon sequestration, namely by using it together with fertilizer, will also provide additional income from carbon credits. Acid soil or dry soil will have better fertility with the application of biochar.

Furthermore, liquid waste or POME (palm oil mill effluent) is used as raw material for biogas. With the main component of biogas being methane (CH4), with steam reforming the methane will react with steam at a temperature of 700-1100 C with a nickel catalyst to become hydrogen/H2 and carbon monoxide/CO. To maximize hydrogen H2 production, the resulting carbon monoxide / CO is then subjected to a shift reaction, resulting in hydrogen / H2 and carbon dioxide / CO2 products. The reaction runs at a temperature of 400-500 C or at a lower temperature, namely 200-400 C. At higher temperatures the shift reaction usually uses an iron oxide or chromium catalyst, while at lower temperatures the catalysts usually used are copper, zinc oxide and alumina. , which helps reduce CO concentrations to below 1%.

Another Form of Reclamation - Energy Plantation for Wood Pellet Production and Integrated Farming

 

Post-mining reclamation is the obligation of mining companies / IUP (Mining Business License) holders so they must prepare funds for this. Apart from reforesting mining areas in forest areas, other forms of reclamation are more flexible because there are many types, but the aim can provide economic, social and environmental benefits. If the mining company does not carry out reclamation, it will receive heavy sanctions, namely a fine of up to 100 billion rupiah. Post-reclamation business or activity management is also flexible according to the agreement as long as it does not conflict with the above objectives.

EFB Pellets with Low Potassium (K) and Chlorine (Cl) for Power Plants

Palm oil mills that have excess energy, especially electrical energy, will have more freedom to develop their business. The excess electrical energy could have come from the production of electricity from the use of biogas. Liquid waste (pome) from palm oil mills is the raw material for biogas production. A palm oil mill with a production capacity of 30 tons of FFB/hour will be able to generate 1 MW of electricity and so on. One of the products that can be processed from the utilization of palm oil solid waste as well as the development of this business by utilizing excess energy is EFB pellets production. With the high price of palm kernel shells or PKS and wood pellets, the driving force or need for EFB pellets is increasing. Global awareness regarding decarbonization or CO2 removal (CDR) or CO2 reduction is the main driving force.

Apart from that, the production of EFB pellets can also be carried out by a separate company by purchasing the raw materials for EFB from palm oil mills. With conditions in Indonesia where there are still very few palm oil mills that have biogas units so that they have electricity supply and can process EFB into EFB pellets, there is still a lot of EFB that has not been utilized and becomes waste that pollutes the environment. This makes EFB pellet producing companies not have to worry about the supply of EFB raw materials. In fact, because the amount or volume of EFB is very large, the EFB pellet plant will be overwhelmed by the abundance of this raw material.

However, due to the high content of EFB in potassium and chlorine (ash chemistry), the use of EFB pellets is limited or can only be used in certain types of power plants, especially stokers and fluidized beds. In fact, most power plants currently use pulverized combustion technology. This is so that the chemical content of ash in EFB must be made as friendly as possible to boilers, especially those with pulverized combustion technology. This can be done so that the chemical content of the ash in the form of potassium (K) and chlorine (Cl) is only less than 2000 ppm. Potassium (K) with a low melting point causes deposits or scale to form in the heat exchanger pipes in the boiler so that the efficiency of heat exchange decreases while chlorine (Cl) is corrosive which shortens the life of the equipment. The treatment was even successful in reducing K and Cl by up to 80% so that the problem of fouling thickness and corrosivity was also reduced by 80%. With the number of palm oil mills in Indonesia reaching around 1000 units, of course the amount of EFB that can be processed into EFB pellets is also very large.

Palm Oil Mill Redesign for IVO Production: Using Pyrolysis, Gasification or Biogas?

The production of biodiesel / green diesel using raw material of RBD PO is too good (overspec) and too expensive, so it needs to be replaced with a cheaper raw material, namely IVO (industrial vegetable oil). For this purpose, it is necessary to redesign the palm oil mill so that a number of FFB extraction production into CPO carried out at the palm oil mill need to modify the process flow. The sterilization process can be eliminated so that there is no need for water for steam production as well as boilers and steam turbines for electricity production. Water treatment units may also be no longer needed or may still be needed but for different processes.

Another important thing is the supply of energy, especially electricity, for this new type of palm oil mill. This is because most of the equipments used in the palm oil mill are mechanical equipments that work by consuming electricity. As the mill that has a lot of biomass waste, it's certainly not a difficult thing to do, even so far, palm oil mills produce their own electricity by burning palm mesocarp fiber and palm kernel shell in the boiler. But in a new type of palm oil mill with a different configuration, the boiler may not be needed or it is still needed but there are differences from before. Basically, of course, how to achieve the highest level of efficiency with the new process.

Another factor is how the new production process also provides greater benefits for the palm oil industry, for example biochar products are also produced. The biochar product will later be used in palm oil plantations to improve soil fertility and also as a carbon sink and absorb N2O gas, which is a greenhouse gas. Carbon credits from the application of biochar as a carbon sink will also provide additional income for the palm oil industry, which is also not a small amount. Currently, many palm oil plantations are located on acid soils or with low pH, which results in low productivity of palm oil yield, so it needs to be increased. Also, in the operation of palm oil plantations, the cost of fertilizer is the highest cost component, and for this reason, biochar is the solution to this problem. With the high productivity of FFB with this treatment, the clearing of palm oil land is no longer needed, so that the focus on palm oil plantations which causes deforestation is also reduced, more info read here.

For electricity production, apart from burning palm nesocarp fiber and palm kernel shell in the boiler, then the resulting steam drives a steam turbine, another way is pyrolysis and gasification of biomass. With pyrolysis (slow pyrolysis) more biochar production or as the main product. Whereas with gasification the product of biochar is less with more main gas product. Biogas from liquid waste (POME) is another energy source that can be used. Basically it depends on the goals and needs, how much electricity is needed, how much biochar is needed and so on. But with the area of palm oil plantations reaching tens of thousands of hectares, the need for biochar will be very large, so pyrolysis will be more suitable to be applied. And if the demand for electricity is large enough, then electricity from biogas can also be used as an addition to electricity from pyrolysis. 

Even with this pyrolysis, other useful products for palm oil plantations will also be produced, such as liquid smoke. This liquid smoke can be used as a biopesticide whose application can use agricultural drones at speeds of 16 hectares/hour or more. Biooil products from pyrolysis can also be used for direct fuel using a burner or further refined to become vehicle fuel. Burning gas or liquid fuels will give cleaner emissions to palm oil mills compared to burning solid fuel that has been done so far.

Digestate from biogas can be used together with biochar so that it can provide maximum results in palm oil plantations. With a porous biochar structure, digestate plus biochar will become a slow release organic fertilizer so that fertilizer use will be more efficient. Apart from that, with the large amount of potential for biomass waste in the palm oil industry, it also allows for a number of business developments, especially if there is an adequate supply of energy. An example is the production of activated carbon from palm kernel shells (PKS) or the processing of kernels into kernel oil (crude palm kernel oil). By optimizing all the potential, especially biomass waste so that it can provide economic and environmental benefits, the palm oil industry will be even more attractive.

Drying Palm Kernel Shells (PKS) by Utilizing Waste Heat from Palm Oil Mills and POME Biogas Units

The need for palm kernel shells or PKS is getting bigger because its use is increasing and diversifying. PKS can be used as boiler fuel in industry and in power plants. In addition, it can also be used as a raw material for activated carbon whose needs are also increasing, for more details, read here. The global trend to decarbonize or replace fossil fuels with renewable energy including biomass fuels, especially PKS is the main driving force for the increasing demand for PKS. Even oil-rich countries with economies driven from oil (petrodollars) are also gradually implementing the decarbonization program.

To be used as fuel or further processed into a number of derivative products such as torrified PKS, PKSC or palm kernel shell charcoal and activated carbon, the PKS must be dried first. The process of drying or reducing the moisture content to a certain level requires energy. PKS, which are palm oil mill waste, are generally just piled up in the backyard of the palm oil mill, so they are usually dirty and wet, resulting in a low selling price. If the palm oil mill can dry and clean its PKS, the selling price will also increase, so that there is added value as well as additional income for the palm oil mill. A number of energy sources from waste heat from palm oil mills can be used for the drying process.

Heat is an energy source that can be used for various purposes, either heat generated directly from the combustion process or from waste heat which is the residual heat from the combustion or other sources such as electricity and so on. In palm oil mill operations there is a certain amount of waste heat that can be extracted or harvested or recovered as a heat source for drying such as heat from combustion in the boiler, heat from steam turbine and heat from the FFB sterilization process. If the palm oil mill also processes its liquid waste for electricity production, the waste heat from burning biogas in the generator can also be used as a heat source for drying the PKS. A number of heat sources which are waste heat when integrated, the amount is large so that it can be sufficient for drying the PKS.

In addition to producing CPO (Crude Palm Oil) as the main product, palm oil mills generally also produce palm kernel. Currently, there are still a few palm oil mills (CPO mills) that also have PKO (Palm Kernel Oil) mills , meaning that there are palm oil mills that process fiber for CPO production and palm kernel for PKO production. The palm kernel is produced from the separation of palm kernel with its shell (PKS). Separation is done by breaking the palm kernel shell in a nut cracker drum, then it can be separated between the palm kernel shell and the kernel or core based on differences in specific gravity. If the palm oil mill wants to get added value from its palm kernel shells (PKS), then as soon as it leaves the palm oil mill it goes straight into the dryer (with waste heat as the heat source) after which it is cleaned with a sieve (screening) so that it becomes the final product in the form of dry and clean PKS, so that higher sale value. The size of the shell and fibers that pass the sieve (undersize), can also be used as boiler fuel. Palm oil mill boilers currently operate using fiber fuel (mesocarp fiber) and part of the palm kernel shell (PKS). The rejected material in the form of undersize can be used as boiler fuel so that less PKS are used.

Biochar for Chicken Farming

With the fast growth of the human population in the world and in line with the need for food or more specifically protein in the form of meat and eggs, the chicken farming industry has become a heavy burden. The projection of protein demand in 2050 is estimated to increase by 69% and almost half of it will come from chicken farms. The main focus of research and development in chicken farming today is how to meet the protein needs above. And that is only possible by developing new technologies to increase the efficiency of the use of feed nutrients in these chickens.

In 2017, global animal feed production has exceeded 1 billion tonnes for the first time and the livestock industry sector accounts for almost half of it, namely 44% of the total feed production or means more than 440 million tonnes alone. With the growth in world population, there is no doubt that the need for feed will also continue to increase. In addition, there is a real environmental impact on the dependence of soybeans from the United States and Brazil as a source of protein for these poultry or chicken farms. Environmental problems are also getting bigger with the presence of nitrogen compounds from the farm in the water flow and pollution of ammonia gas emissions (NH3). In addition, the use of feed with excessive protein content increases the tendency for disease to occur and increases the need for water by the chickens, which causes the problem of dung to become wet and soggy.

There has also been an increase in the use of other protein sources as ingredients for chicken feed, such as legume, peas and so on. But currently its use is still limited due to the compatibility of amino acids, mycotoxins and ease of pelletization. Feed pellet technology is a spectacular 20th century invention that continues to evolve today, for more details read here. The use of low protein feed and the high absorption of these nutrients can be a solution to the problem of ammonia pollution. Biochar can be added as a feed supplement (feed additive) to increase the efficiency of the feed conversion. Biochar in the internal body of the chicken will be able to deactivate a number of toxins and activate microbes either in the chicken intestine or improve the digestive system of the animal. This can be indicated by the rapidly increasing vitality of livestock.

Meanwhile, external factors that affect the health and productivity of chickens are the cleanliness of the cage. Feed factors and house hygiene including air circulation are very important to maintain the survival and productivity level of the chicken farm. The more population with a high density of chicken farms, the greater the pressure on disease. The high nutrient or protein content in chicken manure plus humid conditions is an ideal location for a number of germs to breed. In addition, ammonia emissions are also very damaging to the environment because they will form nitrous oxide (N2O), acidifying soil and eutrophication of waters.

The use of biochar as a feed additive and treatment of manure will minimize the two main problems mentioned above, namely livestock health and environmental pollution. In the end, with the health of the livestock is maintained, the level of livestock productivity is also well maintained. The quality of biochar for feed additives is also different from that of manure treatments. This is of course because the main uses and purposes are different. Biochar for the feed additive needs to be designed in such a way that the grade as a feed additive is met, such as by using selected biomass raw materials, modern pyrolysis technology so that control of the production process can be carried out properly from handling to packaging. As for the use of livestock manure treatment, the quality of biochar is lower, including the use of biomass raw materials, pyrolysis technology and so on. For more details, like the diagram below.

According to a number of studies, adding up to 0.6% biochar in feed increases chicken growth by an average of 17% and it is recommended to mix 0.4-0.6% biochar in the daily feed. Broiler chickens that were given biochar supplements reportedly increased their body weight by 5-10%. If 0.5% of biochar is used as a source of chicken feed additives for world chicken or poultry feed production, the potential need for biochar is 220,000 tonnes annually. And if the chicken manure is used for energy production in the biogas unit, the addition of biochar increases methane (CH4) production and the compost quality of the digestate.

Briquetting of Pineapple Plantation Waste

Pineapple is a fruit that is quite popular throughout the world, this can be seen from the percentage of pineapple fruit production in world fruit production which reaches 8%. Pineapple plants are almost the same as banana trees, that is, after bearing fruit once, the plant dies, and then the production is continued by the saplings for several generations. Or more specifically, pineapple plants produce after 1-2 years of planting and die after fruiting and produce about 70 leaves. The pineapple plants will be dismantled after two or three harvests to be replaced by new plants, which results in increasing pineapple leaf waste. Currently there is almost no utilization of this waste and pineapple leaves also cannot be used for animal feed, so they are only burned or thrown away which also causes environmental pollution. In every hectare of pineapple plantation, the waste produced can reach 3 tons. Large pineapple plantations are usually with an area of  thousands or even tens of thousand of hectares so that the production of this waste is also very much. Handling pineapple leaf waste with an effective and efficient method will certainly provide added value when examined from an economic point of view, so it is necessary to make efforts to handle this waste and briquetting  can be the perfect solution to this problem.

Although both use biomass densification technology, briquetting of pineapple leaves and stems is easier and cheaper than to make pellets. The production of pineapple leaf briquettes can then be used for cooking fuel, industry and even electricity generation. In addition, pineapple leaf briquettes are also used to increase biogas production. There are large pineapple plantation companies that have cattle farming businesses. Cattle farms are chosen mainly because they can use pineapple skin or fruit waste to feed the cows. And because the volume of pineapples produced is also very large, the fruit waste is also large and the cattle farm that is made is also large. The cow manure is usually further processed for biogas production and the digestate of biogas then composted. The compost produced is reused in the pineapple plantation. The briquettes of pineapple leaves and stems added to the substrate or co-digestion will further increase the biogas production significantly. Read here for more details.

With a scenario like the one above, almost all of the biomass waste generated from the pineapple plantation and industry can be utilized optimally. Likewise, the waste from a side business in the form of cattle farming for biogas production. In addition to large pineapple plantation companies, pineapple production centers in Indonesia such as Subang, Pemalang, Prabumulih, Kediri, Blitar, Kubu Raya, Mempawah, Muaro Jambi, Kampar, Central Lampung and Karimun can also develop the above concepts.

Biochar to Increase Biogas Production

Charcoal (biochar) is the raw material for the production of activated carbon. The production of activated charcoal itself goes through two main processes, namely carbonization (pyrolysis) and activation. The surface area of charcoal (biochar) is also smaller than that of activated carbon, but larger than the raw biomass. The carbonization process increases the surface area of the raw biomass. The ratio of surface area between raw biomass, charcoal and activated charcoal is approximately 25 m2 / gram, 200 m2 / gram, 2000 m2 / gram. The larger the surface area of the biomass material that is inserted into the biogas reactor, the greater the penetration of bacteria into the substrate so that the fermentation process that occurs is more perfect so that biogas production will increase. Biochar itself does not participate in fermentation because the main component is stable carbon, while hemicellulose, cellulose and lignin have been decomposed during the carbonization process.

Another example is the addition of biomass briquettes to the biogas reactor, briquetting processs with high pressure and heat also open pores or expand the surface of the biomass, so that biogas production also increases, for more details, read here. The addition of biomass briquettes to the biogas reactor will also increase the C / N ratio, even biochar and activated charcoal have high carbon (C) content.

Charcoal (biochar) has been widely used in the agricultural world to repair damaged soil / soil amendment and thus increase fertility. Good soil fertility will also increase agricultural production. The biochar becomes a home for soil microbes, so that organic materials or compost will break down more completely and be absorbed by plants more as plant nutrients. The charcoal (biochar) pores are the home for these microbes. The more pores, the more microbes will inhabit the biochar as their “house”. The same principle applies to the biogas unit. Another bonus of using biochar is that it absorbs CO2 from the atmosphere, thereby contributing to lowering the greenhouse gases that cause climate change and global warming.

Research in Germany shows that adding 5% biochar to a biogas reactor increases methane production by 5% - based on the dry matter of biochar to the substrate. But when the amount of biochar became 10%, it turned out that no more methane was added. This shows that the optimum condition for adding biochar is the amount of 5%. The microbes in the biochar increase the volume of microbes in the reactor so that the production of biogas or especially methane also increases up to 5%. Biochar itself is not decomposed in the fermentation process. 

Meanwhile, the addition of biomass briquettes per 1 tonne of briquettes will increase biogas production by 400 Nm3. This is because in the biomass briquettes, both cellulose, hemicellulose and lignin have not been decomposed, thus adding to the substrate in the biogas reactor. Whereas in biochar, both cellulose, hemicellulose and lignin have been decomposed during the thermal carbonization process, so there is practically no additional substrate, but only microbial addition occurs in the biochar pores.

The important thing about the addition of biochar is that the compost or digestate produced is of better quality with the addition of the biochar. Biochar will make the compost which is produced as a slow release organic fertilizer. This further encourages biochar production, especially for palm oil companies that care about environmental issues and even strive for zero waste conditions.

Palm oil mills have the potential to apply biogas and biochar units. Solid wastes such as empty bunches and mesocarp fiber can be used for biochar production. Palm oil mills can even replace the furnace in the boiler with a gasifier or pyrolyser. This becomes more profitable because in addition to heat energy being used for production of steam which is used for power generation and sterilization of fresh fruit, biochar will also be produced. The biochar produced is then used to increase biogas production and improve the quality of the compost, as well as a fertilizer mixture in palm oil plantations. And even the potential use of biochar to save fertilizer on large palm oil plantations, for more details can be read here.

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.

Increasing Biogas Production With Biomass Briquettes

For example, activated carbon which has much more pores than ordinary charcoal, or one spoon of activated charcoal is estimated to have a surface area like the area of ​​a football field. With this surface area, activated carbon can adsorb much more molecules than ordinary charcoal. That is what makes activated carbon used by many industries, for more details, you can read it here. The activation process is the process of creating or opening the pores of charcoal so that it has a large surface area. Likewise with the biomass briquetting process, due to the strong pressure and high temperature of the briquetting process with a mechanical press, the micro pores of the biomass will open. The opening of the biomass pores will increase its absorption power. It turns out that according to research at Aarhus University Denmark, the use of biomass briquettes, especially straw briquettes, has been able to significantly increase biogas production. Every 1 tonne of straw briquettes added has increased the 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. Meanwhile, every 1 m3 of POME will produce about 25 m3 of biogas.

The research was conducted on a continous stirred tank reactor (CSTR) biogas type so that the effort to maximize the substrate mixture of biogas was carried out mechanically. CSTR for biogas production is still rare in Indonesia and the Southeast Asia region today, but is common in Europe. The addition of briquettes to the biogas reactor also means adding organic material as raw material for biogas production. But with this form of briquette which has the ability to absorb much more water or 10 times that of bulk straw without be briquetted, which causes microbes to penetrate far more through the micro pores of the straw briquettes, as a result the fermentation process is more perfect. Based on these experiments, the biogas production reached the optimum level at the addition of 10% straw briquettes to the reactor volume. The addition of straw briquettes of up to 10% apparently did not interfere with the performance of the stirrer motor and the straw briquettes because the micro pores absorbed water optimally and did not create floating material that covered the surface of the reactor. 

For biogas factories in Indonesia, especially Southeast Asia in general, especially those that use CSTR for biogas production, of course the above can be a reference and guide for trials to increase biogas production by adding biomass briquettes. In the above case, the straw used in Denmark uses straw from the wheat plant because it is abundantly available there, while in Indonesia and Southeast Asia, rice straw is widely available. The properties of wheat straw and rice straw are so similar that it is also predicted that they will produce almost the same volume of biogas. But if the biogas unit is for example in palm oil mills, biomass sources such as mesocarp fiber, empty bunches and palm leaves can be used as raw material for the briquettes. The biogas unit commonly used in palm oil mills in Indonesia and Southeast Asia using palm oil mill effluent as raw material is a covered lagoon which is not equipped with a mixer. For this type of reactor, one of the efforts to increase biogas production is by making the operating conditions thermophilic. The heat from the biogas power plant can be used to reach this temperature. Can biomass briquettes increase biogas production in covered lagoon reactors? The answer still needs further research.

Why Produce Electricity From Biogas Using Gas Engine Generators? Not With Gas Turbine Generators Or Steam Turbine Generators

  

The need for this type of power plant is always related to capacity, a number of technical factors and the investment costs required. Turbine with generator is a type of generator which is commonly used in industry, especially steam turbine and gas turbine. The grouping of turbine types above is based on the principle of operation and the fluid that moves them. At a palm oil mill, almost all of the electricity is generated from a steam turbine generator. In addition to electricity production, the steam generated from the boiler is also used to process fresh fruit bunches (FFB) to produce crude palm oil or CPO.

Processing of palm oil mill effluent (POME) into biogas and subsequently mostly used for power generation. Almost all of the electricity from biogas is used to meet the needs outside the palm oil mill and the surrounding community. With the potential for palm oil mills in Indonesia that are estimated at more than 1000 units supported by 15 million hectares of palm oil plantations, the potential for electricity generated will be more than 1.5 GW. Approximately 0.7 m3 of liquid waste is produced by the palm oil mill from each tonne of FFB processed. Biogas usually consists of 50-75% methane (CH4), 25-45% carbon dioxide (CO2), and a number of other gases. If wastewater management is not controlled, methane in biogas is released directly into the atmosphere. As a greenhouse gas (GHG) methane has a 21 times greater effect than CO2. The production of electricity from biogas from palm oil mill effluent (pome) is also an effort to reduce environmental hazards. The electricity production from the biogas all uses a gas engine generator and none of them uses a steam engine generator. This is because the production of electricity with steam turbines is not only more complex but also less efficient. The gas engine generator is a power plant that is most suitable for the conversion of biogas to electricity. Gas engines whose engines are similar to gasoline engines, with only the change of fuel into gas (biogas) or similar to vehicle engines such as public buses that run on gas fuel are also more familiar to most people. 

Gas turbine generators are generally used for large capacity power plants. Gas power plants in Indonesia generally use gas turbine generators. Gas turbines are equipment that uses high pressure combustion gases to turn a turbine that can be connected to a generator to generate electricity. Apart from generating power, gas turbines are also used in boats, racing cars and jet planes. The main parts of gas turbines include: compressor, combustion chamber, gas turbine and workload. Each part or segment has a number of critical components which are connected in one axis. During the operation of the gas turbine, some of the power generated by the turbine is used to drive the compressor. The large capacity and technical factors of gas turbine generators make the unit expensive and not used for the production of electricity from biogas. The electricity capacity of biogas from wastewater treatment like POME is not too large, that is, for a palm oil mill with a capacity of 30 tonnes / hour of FFB it will produce about 1 MW of electricity and its multiples. This is the reason why gas engine generators are used in biogas power plants, especially in the palm oil industry.