Biomass Boiler Testing and Selection of Suitable Biomass Fuel

In line with the trends toward decarbonization and sustainability across various sectors of life, particularly in the processing industries (manufacturing/process industries), the use of biomass boilers has become a realistic option today among boilers that utilize other renewable energy sources. Fossil-fuel-fired boilers—such as solid-fuel boilers (coal), liquid-fuel boilers (industrial diesel), and gas-fired boilers (natural gas)—must be replaced with renewable fuel boilers, namely biomass boilers. Apart from technical factors in the form of operational adjustments from previous fossil-based fuels, the suitability and availability of biomass fuels are important factors. Suitability refers to the technical aspect and availability refers to the economic aspect.

Combustion technology for biomass boilers also continues to develop so that efficiency continues to increase. From the beginning in the form of static grates to dynamic moving grates such as chain grates and reciprocating grates, even fluidized beds. And to get optimal performance, biomass fuel specifications must also match the shape, size, calorific value and dryness. If the specifications do not meet the requirements of the combustion technology in the boiler then of course the performance will not be optimal. For example, chain grates are suitable for using fuel that has a uniform size and low water content such as palm kernel shells, wood chips and wood pellets. Apart from that, biomass fuel with ash content which has a high melting point is highly preferred so that the ash does not melt and clog the chain lattice cavity.

Meanwhile, using a reciprocating grate, this system is very reliable for burning biomass with high moisture content (up to 60%), non-uniform size, and high ash content, such as empty oil palm fruit bunches (EFB), bark, and municipal solid waste (MSW). The combustion system moves back and forth periodically (like a moving staircase that moves back and forth) which functions to mechanically turn and stir the fuel. And for fluidized beds, this system has the highest thermal efficiency (>89%) and is very suitable for biomass with very small size (powder/dust), low calorific value, or fluctuating chemical content such as rice husks, sawdust, and coffee grounds. The biomass particle size must be maintained within certain limits so that it can float and fluidize perfectly with the sand bed media. The ideal particle size for a fluidized bed boiler (FBC) generally ranges from 0.1 mm to 10 mm (maximum 30–50 mm for certain components), depending on the specific type of technology used.

As a country located on the equator with a tropical climate, Indonesia is a biomass paradise in the world; read more here. A wide variety of biomass fuels in large volumes can be sourced in Indonesia. The most readily available biomass fuels in Indonesia today are wood chips, palm kernel shells, and wood pellets. Wood briquettes are also available but in limited quantities. Choosing the right biomass fuel will ensure optimal boiler performance, but of course, the economic factors for each metric ton of high-pressure steam produced are equally important. 

Ideally, biomass fuel is available in large quantities, ensuring affordability and high quality. The price of biomass fuel is influenced by various factors, including availability, location, logistics infrastructure, and transportation costs. Furthermore, if the biomass fuel undergoes processing, such as wood pellets and briquettes, production costs also contribute. Palm kernel shells for industrial boiler use in Indonesia require almost no processing; they are simply collected from palm oil mills or CPO mills, which produce waste in the form of palm kernel shells (PKS).

There is a case study regarding the selection of this biomass fuel involving a multinational company. In a certain country, the company’s boilers operate using wood briquettes—specifically, industrial briquettes produced by a mechanical press. This approach was also planned for the company’s plant in Indonesia. However, because producers of wood briquettes are still very scarce in Indonesia—making it impossible to secure a supply—the company ultimately conducted various experiments and trials with different types of biomass fuels and now operates its boilers using wood pellets. Thus, in addition to technical factors, economic factors are also crucial for ensuring optimal and sustainable biomass boiler operations. The trial phase is a critical step in achieving these conditions. 

Hydraulic Press Type Biomass Briquettes, Efficient for Small Capacity

Wood processing factories and sawmills that produce small amounts of wood biomass waste, such as 5-10 tons per day, can process it into value-added products, namely briquettes. Briquettes and pellets both use biomass densification technology, but pellets are far more popular than briquettes. Wood pellets are typically used for large-scale power plants with annual demand of tens or even hundreds of thousands of tons. Briquettes (wood briquettes) are typically used for smaller capacities, and there are also wood briquettes for special applications, such as charcoal and BBQs. The question is, which type of wood briquette is suitable for this small amount of waste?

Compared to wood pellets, which only use one type of production technology—a roller press—wood briquette production uses three types: piston press, mechanical press, and screw press. For more details, read here. Of the three, hydraulic wood briquette is the most suitable type for processing this "small" amount of waste. This is because it uses the least electricity, can operate automatically, and is stable, even for 24/7 operation. The sawmill and wood processing industry, in addition to achieving clean production units (zero waste), also benefits from contributing to renewable energy.

Technically, briquette production is also easier than pellet production, due to the looser moisture content and particle size. Even for abrasive biomass materials, briquetting, particularly with piston presses and hydraulic presses, can handle these materials more effectively than roller-press pelletizing. The wear and tear on equipment in pelletizing these materials is much greater, while in briquetting, this is much less. This is because the contact area during pressing/compaction in pelletizing is much larger than in briquetting. Therefore, in briquetting, it is easier to replace certain machine components that wear out due to abrasive materials, unlike in pelletizing, which requires replacing dies and even rollers.

As the era of decarbonization accelerates, the use of renewable fuels, particularly biomass, such as wood waste, is also growing. Briquetting, particularly hydraulic press briquettes, simplifies handling and use in furnaces. Biomass boilers that feed fuel manually will easily utilize these hydraulic press briquettes. Small and medium-sized industries using small boilers will be able to utilize these hydraulic press briquettes.

Firelog Igniter Briquette, a Unique and Specific Product for Wood Briquette Users

The use of biomass fuels for space heating has been around for a long time, from simple open fireplaces to automated stoves equipped with IoT (Internet of Things). From firewood collected from forests to the use of wood pellets and (on a smaller scale) wood briquettes. The driving forces related to decarbonization, climate change, and the environment also play a strong role in the use of biomass fuels, especially wood pellets. Premium-grade wood pellets are an option for space heating with a very low ash content of less than 1%, known as A1/A2 pellets. For more details, read here, as well as for wood briquettes (consumer briquettes). The main difference between wood pellets and wood briquettes is their size, and sometimes their shape, and their production technology is also more diverse than wood pellets. For more details, read here.

For wood briquette (consumer briquette), there are various stoves that can use it, but generally, any stove or oven that uses firewood can use it. Because firewood is no longer readily available in Europe, many people purchase wood briquette from vendors who typically also sell stoves or ovens. In Europe, wood briquette is sold directly to buyers on pallets or through supermarkets.

The size of briquettes makes it difficult to light them directly with a match. Typically, they are lit in a separate place (firestarter), using small twigs or breaking the briquettes to make them ignite more easily. However, this is considered difficult and impractical. This is why innovations have emerged in the form of briquettes enriched with paraffin, making them easy to ignite as starters for briquette stoves. These briquettes (igniter briquettes) can be easily lit with a match and are more practical. Currently, paraffin is generally derived from petroleum, making it a fossil fuel. To be more in line with the aforementioned decarbonization and climate change initiatives, paraffin sources should also be renewable, such as from plants. HRBDPS, or hydrogenated RBD palm stearin, derived from or derived from palm oil, can be a substitute for paraffin from this fossil source.

Wood Chip Production Waste for Wood Pellet or Wood Briquette Production

The production of wood chips as biomass fuel in cofiring of PLN's (Indonesia's state-owned electricity company) coal powerplants has been increasingly popular lately. Wood chip production is the easiest biomass fuel production compared to various biomass fuel products currently produced by the industry. The availability of raw materials is the main factor in the sustainability of production. The calorific value of wood chips depends on the species or type of wood used and its dryness level (water content). Hardwoods and low water content are ideal products for wood chips. And because it has a low bulk density of around 250 - 350 kg / m3, the transportation factor is another aspect that is very important for the delivery of wood chip products.

The particle size of wood chips has also been determined so that handling and storage are easier. To obtain the desired particle size of wood chips, screening is carried out after the wood trunk or pieces are chopped with a wood chipper machine. With these prerequisites, there are products that are rejected from the production process, namely wood chip products that are too large (oversize) and products that are too small (undersize). Products that are too large (oversize) can be returned to the chipper machine to be chopped again, but wood chip products with particle sizes that are too small (undersize) must be used for other things so that in addition to zero waste wood chip production, it can also provide additional income for the wood chip producer.

Small particle sizes such as sawdust from wood chip waste production can be used for the production of wood pellets or wood briquettes (pini kay briquettes). And even wood briquettes are more tolerant of slightly larger particle sizes because wood briquette products have a higher density than wood pellets, in addition wood briquettes can also be further processed into charcoal briquettes (sawdust charcoal briquettes). Wood briquettes themselves are commonly used in countries with four seasons, especially in winter for home heating. While charcoal briquettes (sawdust charcoal briquettes) are commonly used for BBQ, especially for Middle Eastern countries and Turkiye.

In the production of wood chips, it is estimated that biomass waste that is approximately the size of sawdust is around 20-25%, meaning that if wood chip production reaches 5,000 tons/month, the waste is around 1,000 - 1,250 tons/month. This is sufficient for the production of wood briquettes and sawdust charcoal briquettes. Meanwhile, if you want to produce wood pellets, especially for the export market, usually a production capacity of around 5,000 - 10,000 tons/month is needed. Of course, this cannot be done. In addition, the investment in equipment for the production of wood briquettes, sawdust charcoal briquettes and even wood pellets for this purpose is also much larger than the production of wood chips. This makes it more reasonable if the production of wood briquettes or sawdust charcoal briquettes is carried out by other parties. The other party will process the wood chip factory waste into wood briquettes, charcoal briquettes (sawdust charcoal briquettes) and because the complexity of production and equipment costs are also higher, it is natural that the profits obtained from processing this waste are also higher.

The world price of wood pellets, like palm kernel shells (PKS), has fluctuated a lot, and lately the price has tended to be low. Palm kernel shells (PKS) themselves are biomass fuels that are competitors of wood pellets in the global market but are cheaper because they come from one of the solid wastes of palm oil mills that are processed simply. With these conditions, coupled with the fact that it is very difficult to obtain adequate volumes of waste from wood chip factories, the production of wood briquettes (pini kay briquettes) or charcoal briquettes (sawdust chracoal briquettes) becomes a rational choice. In addition, the stable price of the two products makes it even more attractive to consider them.

Encouraging the Machinery Industry to Support the Bioenergy Industry

When realizing that Indonesia is a biomass “heaven” so that it has the potential to become a world leader in bioenergy, then a number of efforts should be made to support this. Production equipment or machines are one of the components that support this. For example, large-capacity wood pellet production usually relies on European machines that have proven to be reliable so that the wood pellet business goals can be achieved. Cost to benefits ratio analysis is used in selecting these European machines. However, because buying European machines with complete production lines is expensive, the use of combination machines is an alternative. The complexity and heart of a production process usually lies only in the main equipment and this is still imported, while supporting equipment should be able to use local production equipment.

When production equipment can work according to its capacity and function, the production target (quantity and quality) can be achieved. Choosing a number of supporting equipments that is appropriate and able to operate according to the needs of the main equipment is not easy. Getting a local machine manufacturer partner to get a match between the characteristics of the main machine and the supporting machine does take time and process. But to be able to play a role and reduce risk in the decarbonization era, it can be started by supporting some equipment at a small capacity or limited to certain equipments only. Engineering and design factors are the main important factors before fabricating the supporting equipments.

Of course, if a number of supporting factors are met, such as mastery of science and technology, experience, good company organization and so on, then 100% production of production equipment or complete lines can be done. Of course, it takes time and effort that is not simple, such as maintaining the performance of the quality of the machine product so as to provide satisfaction to users with the hope that business performance will also increase and research is ongoing. And by gradually becoming part of actively participating in various bioenergy projects, mastery of technology through technology transfer is also possible. Being part of the solution and playing a role in it is an important thing to do, including in the machinery industry that supports the bioenergy industry.
 

Size Reduction: Shredder or Chipper ?

There are many biomass processings that require size reduction. With this size reduction, the biomass raw material has a smaller and more uniform size and shape, making the follow-up process easier. After reducing the size, the surface area or contact area becomes larger so that the drying process will be more efficient, especially in continuous drying. The small and uniform size also makes handling easier. Size reduction is usually used in the initial / pretreatment process before the main / core process of processing a biomass.

Biomass, especially from plants, also has various shapes and sizes. This greatly influences the size reduction equipment used. Fibrous biomass such as coconut fiber or empty oil palm fruit bunches will be more effectively and efficiently reduced in size with a shredder rather than a chipper. This is because the fiber dominant and tenacious structure is easier to tear or shred and crush than to cut into pieces like using a knife.

Meanwhile, woody biomass has hard, brittle characteristics and an elongated shape, so the use of a chipper is more effective and efficient compared to a shredder. The character of the wood is easier to cut with equipment such as a knife for size reduction. The output or product from the shredder and chipper is also different in terms of size and shape. The wood produced from the chipper machine is usually called wood chips and looks like chopped wood, while the output from the shredder is in the form of shreds.

Biomass processing products into energy, namely by compaction (densification) into pellets or briquettes, as well as thermochemical routes such as pyrolysis, gasification and combustion are widely used today. If the size and shape of the biomass from the size reduction equipment is suitable, it can be used immediately. However, if the shape and size are not suitable then it is necessary to continue with the next size reduction stage, namely using a hammer mill so that a biomass product is obtained that can be the size of sawdust. In the production of pellets and briquettes, the biomass particle size needs to be made as small as the sawdust, so that compaction (densification) is optimal. Meanwhile, in the thermochemical process, the size of the biomass becomes small particles such as sawdust, usually for equipment that carries out fluidization, for example fluidized bed combustion.

Production of Pini Kay Briquette from Plywood and Veneer Factory Waste

Indonesia's plywood production is estimated at more than 10 million cubic meters each year, which is produced from hundreds of plywood factories, even Indonesia once dominated the world wood industry in the period 1980 to 1995. The existence of plywood factories in Indonesia has actually been around for a long time, but its development only became apparent after in 1972. After the period 1980-85 the number of factories increased rapidly. At that time there were no less than 110 medium to large scale factories in almost all provinces in Indonesia. There are five provinces as the largest plywood producers in Indonesia, namely East Java, East Kalimantan, Central Java, South Kalimantan and West Kalimantan. And six other provinces that are starting to develop are Banten, Papua, Central Kalimantan, South Sulawesi, Riau and Jambi. Most of the plywood is for the export market.

APKINDO (Indonesian Wood Panel Association) is a forum for plywood and veneer industry players. When APKINDO was formed on February 12, 1976, it was initiated by 13 plywood companies, while currently it has members from more than 125 industries spread throughout Indonesia. APKINDO aims to foster unity and togetherness and voice the interests of the plywood industry to utilize logs more efficiently, absorb more labor and increase added value. APKINDO's role continues to this day, one of which is to support the SVLK policy which is believed to be able to restore the positive image of Indonesian forestry in the eyes of the world, so that it will make it easier for Indonesian wood products, especially plywood, to win competition in the global market. 

The volume of wood waste in the plywood industry is quite large, reaching almost 55% or more than 5 million tons per year of national plywood production. The potential for this waste is quite large and has great potential to be processed into pini kay briquette (wood briquette screw type). Why should have to process it into pini kay briquette (wood briquette screw type)? Pini kay briquette is the choice for the solution to the plywood waste problem because apart from the production process being easier, the machine investment is also cheaper. This is because plywood factory wood waste is already dry so it does not require a drying process. Apart from being quite expensive, the dryer also have operational costs. It is also very possible to obtain high quality due to the low ash content, because the wood for plywood production has been debarked so that the content can be reduced to below 1%.

Veneer is a thin sheet of board used to make plywood. The veneers are arranged and glued together, in odd quantities, so that they become plywood. Many veneer manufacturers do not have plywood manufacturing units, but in general plywood factories have veneer production units. Veneers can be made by peeling (rotary cutting), slicing, sawing and sharpening. Indonesian veneer production is currently quite large as is the waste it produces. This waste will also have great added value by processing it into pini kay briquettes, just like the plywood waste above.

The pini kay briquette production process can use the plywood and veneer industry waste mentioned above. Before being compressed into pinikay briquettes in a briquette machine or screw press, the waste needs to be uniform in size to the size of sawdust and also have a dryness level of around 10%. Wood waste that is large in size needs to be reduced in size first and the dryness level also needs to be tried to reach the 10% range. With a screw press / extruder, wood biomass from these wastes can be compacted (densified) up to 1400 kg/m3 or much denser than wood pellets which are around 700 kg/m3. The pini kay briquette product can then be cut into certain sizes and ready to be marketed, especially for the export market. The need for pini kay briquettes is mainly as space heating fuel. Furthermore, this pini kay briquette can also be further processed into charcoal briquettes or commonly called sawdust charcoal briquettes. With this density, the burning time for briquetted charcoal is twice that of ordinary charcoal or more. Meanwhile, the main use of charcoal briquette is for barbeque.

For the plywood and veneer industry which produces up to thousands of tonnes of woody biomass waste every month, potentially becoming an environmental problem, the production of pini kay briquette could be an effective solution. And if there is a plywood and veneer industry that is interested in producing pini kay briquettes, we are ready to help the market.

Don't Choose The Wrong Machine: Wood Pelletizer With Feed Pelletiser, and Wood Extruder With Charcoal Extruder

The visual appearance alone can sometimes be unbelievable. Two things can visually appear the same or very similar but turn out to be different. This often happens in the production of wood pellets and wood briquettes (pini kay briquette / uncarbonised briquette). And what's worse, this machine is the heart of the industrial production process, namely the pelletiser in the wood pellet industry and the extruder in the wood briquette industry (pini kay briquette / uncarbonised briquette). So that errors in selecting the machine can also have fatal consequences, namely not only is the production target not achieved, even the product in question is not successfully produced. This is why the buyer or user of the machine must be careful about the machine that will be purchased and used.

In the wood pellet industry, mistakes often occur, namely pelletisers are used for animal feed but are used for wood pellets. As a result, wood pellets may not be formed at all because the power for feed pelletisers is much smaller compared to pelletisers for wood or wood pellet production. Offers of cheap prices often make buyers or users tempted and do not look further, so that as a result they will be disappointed.

Likewise in the wood briquette industry (pini kay briquette / uncarbonised briquette). Wood extruders also have much larger motors than charcoal extruders. Briquettes produced with a wood extruder apart from not requiring additional adhesive are also denser and harder due to the use of a high-powered motor. The mistake that can occur is that a charcoal extruder is used for a wood extruder and this also usually happens because the price is cheaper. The briquettes produced from the wood extruder can then also be made into charcoal, producing the final product in the form of charcoal briquettes. Although charcoal briquette production using a charcoal extruder will also produce this product, the process route and product quality are different. Below is the route for the charcoal briquette production process.

The raw material used in route 1 is wood dust such as sawdust which is then pressed or compacted with a wood extruder. With strong pressure and high heat, no additional adhesive is needed, but lignin, which is a natural polymer found in wood, acts as an adhesive. The resulting briquettes can then be charcoaled in a carbonization furnace and the final product is charcoal briquettes. Meanwhile, in route 2, the raw materials are charcoaled or carbonized first, then the charcoal is mixed with adhesive, usually starch and pressed or compacted using a charcoal extruder. The use of additional adhesive is because in charcoal, lignin has been decomposed in the previous carbonization or carbonization process. The final product produced is charcoal briquettes. The quality of the charcoal briquettes in the route 1 process is better than the route 2 process because apart from being denser so the burning time is longer as well as the heat produced.

So, in order not to make the wrong choice, buyer / user have to be careful and precise about the specifications of the machine, as well as knowing the raw materials and production process and don't be easily tempted by offers of cheap prices. The greater the production capacity, the greater the need for pelletiser and extruder equipment, so that if the wrong choice occurs, the risk is fatal, because these machines are expensive. It is also important to note that the equipment purchased also comes from a manufacturer that has been tested so that it has reliable performance.

Dichotomy of Energy Plantation and Legumes Plantation

There is a dichotomy between friends in livestock and forestry today about these legumes. From animal husbandry, they see leaves as a source of feed protein from plants and from forestry, they see wood as a source of wood that is easy to cultivate with high productivity. In the forestry sector, the wood is usually used as a renewable energy source such as wood chips, wood pellets, wood briquettes or charcoal briquettes. Forestry grows thousands of hectares of these legumes such as gliricidia with a wood orientation while the leaves are considered a by-product or waste from their plantation side. By utilizing the wood and leaves, it means getting out of this dichotomy, creating a new paradigm and being able to overcome food and energy problems or optimize the legume plantation or energy plantation (whole tree utilization) of thousands of hectares.

In addition to functioning as a legume plantation for animal feed, especially ruminants (sheep, goats, cattle, buffalo), as well as biomass fuel as above, the same plantation can also be used as a raw material for synthetic fiber board, for more details, please read here . Meanwhile, as the bioeconomic era is getting closer, the need for bioenergy, especially wood pellets, is increasing, the need for animal feed, especially ruminants which is part of the chain of human food needs is also increasing and indeed the growth of the earth's population is also increasing, and the need for biomaterials such as synthetic boards is also increasing. Therefore, the establishment of energy plantations or legume plantations or biomass plantations is very important, strategic and multi-beneficial. Based on these conditions, it is not impossible that in the near future the plantation will become a national and even global trend.

Briquette For Textile Industry

As the demand to become an environmentally friendly industry enters this era of decarbonization, a number of industries have begun to switch to using renewable energy in their production processes, and the textile industry is no exception. You can read about the urgency of a biomass boiler here. A number of boilers are used in the textile industry with the type of boiler that uses a static (static grate) and dynamic (moving grate) furnace. From the operational point of view, a dynamic furnace (moving grate) is easier and more efficient because the combustion process can be more complete. In addition to general fuel specifications such as calorific value, moisture content, ash content and so on, the size and shape of the fuel is also an important factor in the efficiency of the combustion. Wood pellets with a diameter of generally 6 mm and 8 mm and palm kernel shells with a size of about 1 cm to 5 cm are sometimes not suitable for this type of boiler. For these conditions briquette can be the solution. Briquette sizes are not only bigger but also more diverse, including the briquetting technology used, for more details on briquetting technology, you can read here.

Biomass waste, both wood processing industry and agricultural waste such as rice husks, can be used as raw material for these briquettes. Briquette shapes such as pucks or cylinders or short octagonals can be a solution for certain types of boilers. Currently, there is still a lot of wood waste that has not been utilized and even polluted waters such as rivers that can be used for the production of these briquettes, more details can be read here. Meanwhile, rice as a staple food source for the Indonesian population also produces a lot of waste in the form of rice husks. Indonesia's rice production in 2008 is estimated to reach 59.9 million tons of milled dry grain with a husk composition of 25%, meaning that the husk potential reaches 15 million tons/year. Although the amount is abundant but generally its utilization is still not optimal, this is because rice husk has a low bulk density and relatively small calorific value due to the high ash content. Indeed, with biomass compaction technology such as briquetting, the biomass waste becomes easy to use, economical for long-distance transportation and overcomes environmental pollution problems.

Whereas in Indonesia, almost all of the briquettes produced are screw extrude types which are actually not very suitable for the boiler solution. This is because this type of briquette is not only long in shape and also requires a large amount of energy or electrical power for the production process. Cutting it into small pieces will be an additional job in itself. While the mechanical press type to get small pieces to form pucks is easy to do and also requires less electrical power. As a comparison, screw extrude briquettes to produce 1 tonne of briquettes require about 100 kW of electricity, while on a mechanical press to produce 1 ton of briquettes, electricity is needed only 50 kW or half. In addition, when using abrasive raw materials such as rice husk which has a high silica content for a screw extrude type briquette machine, it will only have a short life, while the mechanical press has a much longer service life.

Wood Chip, Wood Pellet, and Wood Briquette from Energy Plantations for Local Market Part 2

The PLN (Indonesia State Owned Electricity Company) cofiring program, which is mixing biomass fuel with coal in coal power plants, will clearly encourage the use of biomass as an energy source. Cofiring is the easiest and cheapest way for coal power plants to start entering or gradually using environmentally friendly renewable energy. Emissions are also getting better as the use of biomass fuels increases, such as because the sulfur content is very low, there is little ash instead of hazardous waste, and fly ash is very small. The amount of added biomass, for example, starts from 1% which is then gradually increased and even finally it can be 100% biomass or renewable energy. In 2020 the cofiring program has been initiated with a target of 37 coal power plants and by the end of 2020 it is reported that it has been implemented for 20 coal powerplants. While in total there are 114 coal power plants units owned by PLN that have the potential for cofiring, spread across 52 locations with a total capacity of 18,154 megawatts (MW) with a target of completion in 2024. Consisting of 13 coal power plant locations in Sumatra, 16 coal power plant locations in Java, Kalimantan (10 locations), Bali and Nusa Tenggara (4 coal power plant units), Sulawesi (6 locations) and Maluku and Papua (3 coal power plant locations). Meanwhile, the cofiring ratio ranges from 1-5% biomass with an estimated biomass requirement of 9-12 million tons per year. Technically, with the 1-5% cofiring ratio, the PLTU also does not need to modify its equipment, so that it can be used immediately after the biomass fuel meets the required specifications.

When detailed about the type of technology used by coal power plants in Indonesia today, there are three types of coal power plant, namely, 43 types of PC (Pulverized Coal) with a total capacity of 15,620 MW requiring a mixture of 5% biomass or the equivalent of 10,207.20 tons per day, 38 types of CFB ( Circulating Fluidized Bed) a total capacity of 2,435 MW requires 5% biomass or the equivalent of 2,175.60 tons per day. Meanwhile, 23 types of stoker with a capacity of 220 MW use 100% biomass or the equivalent of 5.088 tons per day. In the short term, the type of biomass used is waste based, while in the long term it is from energy plantations. The Ministry of Environment and Forestry has also allocated a land area of ​​around 12.7 million hectares for the provision of forest land to jointly support the coal power plants biomass supply program. Ex-mining lands covering an area of ​​about 8 million hectares should also be reclaimed using this energy plantation. Even PLN has also signed a memorandum of understanding or a Memorandum of Understanding (MoU) with PTPN III Holding (Persero) and Perum Perhutani. In this case, PLN is the owner of the PLTU, while Perhutani has the resources of industrial forest areas both in Java and outside Java that can be developed as energy plantations. Likewise with PTPN III which has land for the development of energy plantations, read here for more details.

To fulfill the need for biomass as an energy source, energy plantations must be increasingly encouraged. The production of biomass fuels from energy plantations takes longer than processing forestry and agricultural wastes such as felled wood waste, sawdust, wood waste from the wood processing industry, palm oil empty fruit bunches, coconut husks, rice husks, and so on. . The route or option with energy plantations was chosen because in addition to ensuring the quality and quantity of biomass fuel it also optimizes land use, including being integrated with livestock and can be harvested multiple times (coppice) without having to replant for the next harvest. In fact, because energy plantation plants use legumes such as gliricidia and calliandra, which the roots can fix nitrogen from the atmosphere, soil fertility also increases. However, more and more efforts are needed for the energy plantation route because it takes at least 2 years for these crops to be harvested and before that it also needs to prepare the soil and plant the trees.

As previously stated, the choice of production for the type of fuel from energy plantations is influenced by several factors, such as the distance between energy plantations and industrial users, production capacity, industrial needs according to combustion technology and investment cost. If the industrial location or power plant is close to each other, even in the energy plantation area, it is sufficient only to make wood chips from the energy plantation. This is because transportation costs are cheap. Meanwhile, if the location is far enough, the wood should be processed into wood pellets or wood briquette. Wood pellets are indeed much more popular than wood briquettes, although technically wood briquette production is easier and production costs are cheaper. In addition, technically, the density of wood briquette can also be higher than wood pellets. This becomes interesting if a producer is interested in wood briquette production as a product diversification and biomass densification technology.

 

For sustainability, energy plantations will also be better than the use of agricultural and forestry wastes or the timber industry as mentioned above. This is because the plantation is designed and made specifically for the purpose of wood as an energy source. This also makes the volume of wood production more certain than relying on the volume of waste, whose availability depends on the main product. Energy plantations and the following livestock businesses are likely to become an exciting new trend and hopefully the momentum will not be anymore.

Wood Chip, Wood Pellet, and Wood Briquette from Energy Plantations for Local Market

The floods in South Kalimantan in January 2021 almost drowned one province

To be able to provide benefits and maintain environmental balance, forests must be managed or according to their purpose. The conversion of forest land to palm oil plantations, housing and so on will create an imbalance in the environment as a result of which natural disasters will occur. In-depth and comprehensive studies have certainly been carried out to determine the use of the land so that its sustainability is maintained and benefits human life. When the benefits for human life, especially the economy, are a priority and dominant, then the balance of the environment is automatically disturbed and natural disasters are ready to lurk at any time. The laws and regulations that are supposed to maintain this balance are imposed and amended for that purpose. For example, regulations on the minimum area of ​​a protected forest area in an area are no longer needed or adapted to conditions so that it is very vulnerable to fraud. And when human greed is getting out of control because it is so materialistic, the nature and the environment is getting more and more damaged so that the consequences are natural disasters everywhere such as drought and forest fires in the dry season, floods and landslides in the rainy season and so on.

On the other hand, industrial forest plantations (HTI) which are intended for economic aspects must also be used optimally, as well as a number of idle lands and so on. Energy plantation is one of the best options, more details can be read here. As a source of fuel or an energy source from biomass, the wood produced in energy plantation can be processed into wood chips, wood pellets or wood briquettes. The choice of product to be produced depends on a number of things such as the distance between the energy plantation and the industrial user, production capacity, industry / market needs and investment value. The closer the industrial users or markets are to energy plantations, the simpler biomass energy products are, such as wood chips. Biomass densification such as pellets and briquettes is needed if the location of the energy plantation and the user is far away so that transportation costs are high. By densification into pellets or briquettes, transportation costs can be saved, as well as more efficient storage, easier handling and use.

Palm kernel shell (PKS) is a biomass fuel which is also abundant in Indonesia, more details about PKS can be read here. This PKS is also a competitor for biomass fuel from the energy plantation. Previously, much PKS were exported to Japan and Korea, but the imposition of high export tax and levy made the price less competitive, for more details can be read here. This also further encourages the use of PKS for industry in the country. Moreover, starting in 2022, PKS that enter Japan must also be RSPO certified or this is analogous to wood pellets with its FSC.

 

Ideally, PKS should be used for domestic industries because besides being cheap, the volume is also large. Domestic industries can be more competitive if the fuel is cheap. Meanwhile, wood pellets from energy plantations are for export orientation. In addition to the added value being greater than the wood pellet production activity itself, labor absorption is also more. However, in certain periods the supply of PKS can be disrupted, such as a decrease in the production of CPO or palm fruit during the low crop season, the location of palm oil mills in remote areas, resulting in difficulties in transportation / logistics and weather at sea. With the condition that most of the industries are located in Java and there are still thousands of hectares in Java for making energy plantations, under certain conditions energy plantations and wood product processing are quite prospective in Java. Continued.

Biomass Boiler and Its Urgency

A problem that is visible and can be felt, especially if it has a short-term impact, is certainly easy to map and find a solution to. But if the opposite namely is not visible, it is difficult to feel and the impact or effect is long-term, of course it is more difficult to map, let alone find a solution. The use of fossil fuels, especially coal in a number of industrial boilers, is an example. The effects of exhaust emissions in the form of COx, NOx and SOx may be difficult to detect at first but create environmental damage in the long term. Likewise heavy metals like mercury which also have long-term effects. Meanwhile, fly ash pollution and boiler furnace ash (bottom ash) are clearly affected more easily. In a larger case or global scale, namely climate change and global warming due to greenhouse gases, especially CO2 (carbon dicside), a global consensus is also needed to solve these problems. That is what makes the Earth Conference on Climate Change (UNFCC) always held every year, which has so far been recorded 27 times, lastly in 2019 in Madrid, Spain, while what was supposed to be held in 2020 was postponed in 2021 due to the COVID-19 pandemic. Fossil fuels including coal are carbon positive fuels so that their use will increase the concentration of CO2 in the atmosphere, while biomass fuels such as wood chips, wood pellets, wood briquette and palm kernel shells (PKS) are carbon neutral fuels. It is said to be carbon neutral because of the use of this fuel because it does not increase the concentration of CO2 in the atmosphere.

 

Boilers are essential equipment for the operation of a number of industries. The main function of the boiler is to produce steam which is used in the industrial production process. But when the boiler is not operated and maintained properly, the boiler can be dangerous. The continuity of production operations also greatly depends on this equipment, so that disruption of boiler operations will have a significant effect on this production. The boiler also consists of a number of subsystems that work in harmony, such as boiler burners and controls, water treatment for boiler feed water preparation, fuel handling and feeding and so on. Sometimes a number of subsystems are supplied from a number of different vendors, so synchronization between these subsystems is very important. This makes boiler operations safe, efficient, reliable and minimizes boiler downtime. And of all the subsystems in the boiler, the burner system is the most sophisticated subsystem in the boiler unit. The burner system has a number of operational modes that require extensive training and / or experience for boiler operators to be well understood.

Currently, a number of industries have started to switch from fossil fuels to biomass fuels. In industries that previously used solid fuels, technical changes or furnace modifications can be minor, while in industries that previously used gas or liquid fuels, the usual thing to do is replace the boiler unit (including the furnace). Of course, the replacement of the boiler unit is also followed by its supporting systems such as fuel storage, provisioning and so on. Petroleum fuels, coal and natural gas are consistent fuels with standard quality and their contaminants or impurities have been known and studied for decades. Whereas with biomass there are a number of options and each source is also unique and also the level of contaminants.

In certain cases, industries that will switch to using biomass, namely palm kernel shells (PKS), that previously using natural gas, so the industry needs to study and analyze the implications of using the PKS. And because the use of PKS for industrial fuel is relatively new, the industry can use old data about their furncae operations with natural gas and compare it to furnace that use solid fuels like coal - which is commonly used by the industry today. Although PKS is also a solid fuel, there are a number of characteristics that distinguish it from coal. In addition, gas combustion can be said to be the most ideal combustion process, which is in terms of stoichiometry or the perfection of combustion compared to combustion of liquid or solid fuels. Large particle size such as coal will also have an effect on combustion and also make a fuel more difficult to burn. So that from this comparison, the industry can get an overview of the burning of the PKS and the scheme below to describe the case.

With adequate analysis, planning and system design, the use of new fuels, especially biomass, such as wood chips, wood pellets, wood briquettes and PKS can be implemented properly. Energy prices and environmental regulations are driving forces for the use of this new fuel. Fixed bed combustion type furnaces are most commonly used in a number of industries. These furnace variants include grate furnace types namely traveling grate, fixed grate system, incline moving grate & horizontally moving grate, vibrating grate, cigar burner and underfeed rotating grate, while other types are underfeed stokers. Meanwhile, the fluidized bed and pulverized combustion types are generally used by power plants. The technical considerations for selecting biomass-based solid fuels include heating value, moisture content, ash content, density, particle size, emissions, availability of these fuels, and suitability for the furnace. In the end, the most optimal combustion rate that is safe and meets environmental standards is the purpose of using the biomass fuel.