Wood Pellet Production from Acacia Industrial Plantation Forest (HTI) Waste

Acacia forests or plantations in Indonesia are estimated to reach 2 million hectares and almost all of these acacia forests are used to supply pulp and paper mills. Every pulp and paper mill always has acacia forest with an area of ​​​​thousands of hectares to meet the pulp and paper mill. Acacia wood with a minimum diameter of 8 cm is used as the raw material, while those with a diameter smaller than that are only used as waste. After the tree is cut down, then a new planting is carried out (replanting). If every one hectare produces 20 tons of acacia wood waste, then with an area of ​​20,000 hectares, 400,000 tons of acacia wood waste is produced. The area of ​​20,000 hectares of acacia plantations is not too big, this is because there are a number of HTI (industrial plantation forest) concession holders which cover an area of ​​hundreds of thousands of hectares, so the volume of wood waste produced is also very large. The wood waste is very potential for the production of wood pellets. The need for wood pellets is also increasing along with the decarbonization program or fossil fuel substitution.

Wood products come from different parts of the tree, each tree has a unique potential, depending on a number of factors including the diameter and straightness of the trunk. In acacia trees trunk diameter is the main parameter.

For the production of wood pellets, you can use raw materials from wood waste or wood that worth of waste wood. This is why wood that is valuable or has a high economy is not suitable for the production of wood pellets (from an economic point of view). Users of wood pellets are mainly for power plants so that the volume of their needs is large. Waste wood such as from acacia plantations is very potential and suitable for the production of large capacity wood pellets. In addition to Japan and Korea as the largest wood pellet market in Asia, currently Europe is also increasingly being encouraged to use wood pellets. The occurrence of the Russia-Ukraine war was one of the driving forces. The dependence on fossil fuels from Russia has become a concern for European countries in particular, so that the urge to use renewable energy is getting bigger. Biomass, especially wood pellets, also has a large portion in the plan to use renewable energy in Europe, especially in the RED (Renewable Energy Directive) II. Even in the current war conditions, the need for wood pellets for space heating is also getting bigger, although for this segment, especially firewood is their main fuel. With the disruption of energy supply from Russia, it is predicted that this winter will be a tough winter in Europe.

PKSC For Activated Carbon Production

The production of palm kernel shells (PKS) in Indonesia and Malaysia is very large, with more than 15 million tons annually which comes from palm oil mill waste. There are about 20 million hectares of palm oil plantation from these two countries (Indonesia and Malaysia) as sources of crude palm oil and are the largest in the world today. Utilization of PKS can be optimized for the production of activated carbon. The demand for activated carbon is predicted to increase by around 10% per year and the demand will reach nearly 4 million tons in 2021 worth 8.12 billion USD, while data in 2015 recorded global activated carbon production of around 2.7 million tons worth 4.74 billion USD. Powdered activated carbon (PAC) has the largest market share followed by granular activated carbon (GAC). The high demand for PAC is mainly driven by the need in a number of industries such as chemical, petrochemical, food and beverage for decolorizarion and deodorization applications. More specifically, the use in the liquid phase has the largest portion.

However, it is recognized that coconut shell is the current favorite material for activated charcoal production, and PKS is likely to be the next priority. The area of ​​Indonesian coconut plantations is estimated at around 3.7 million hectares so that the number of coconut shells that can be used as activated carbon is also not as much as PKS because the area of Indonesian palm oil plantations has also reached approximately 15 million hectares. With a coconut plantation area of 3.7 million hectares, coconut shells have a composition of 12% of coconuts so that the total coconut shells that can be produced are around 23,000 tons/year. This is in stark contrast to PKS which have the potential to reach tens of millions of tons every year.

The characteristics of coconut shells are also almost the same as PKS. Likewise for the use of activated carbon which emphasizes factors such as hardness and ash content. The harder the material and the smaller the ash content, the better the quality of activated carbon produced. Currently there is a need for palm kernel shell charcoal / PKSC  of 20,000 tons / year for the raw material for the production of activated carbon. Groups of palm oil companies that have a number of palm oil mills (1 group of palm oil companies having 5 palm oil mills is common in Indonesia) or other private parties by taking raw material for PKS from these palm oil mills to be able to produce PKSC to be exported as raw material for the activated production. The use of a large capacity carbonization (pyrolysis) equipment that works continuously is needed to meet these needs. This will be a business development for the palm oil companies and will be more environmentally friendly because less solid biomass waste is produced.

Complete Pellet Production Line (Fuel and Feed) Small Capacity For Research and Experiment

Laboratory equipment as a production unit or as a small factory (mini-mill) is needed both for learning (research and experiment) and as a production stage before reaching the commercial stage of a business. By observing and conducting trials on the mini-mill, in addition to getting a complete understanding of the production process from A to Z, we can also make detailed and in-depth observations of each stage of production in an easy and inexpensive way and provide a more complete picture for the commercial production process later. It is also easy to do research and experimentation on various kinds of raw materials, both single material and a mixture of several raw materials. Currently, there are many researchers and practitioners who want to try a raw material to make pellets but have difficulty finding partners or companies that can do it. Setting up equipment with mini-mill facilities is also much easier, in contrast to large factories. This is why in general large factories do not want to accept trials of making pellets from a certain material, because their focus is on production targets, unless they have R & D facilities for these trials.

Meanwhile, if the laboratory equipment is only in the form of functional tools such as cutting tools, crushing tools and so on but is not integrated into a production unit (even though the capacity is small), it will be difficult to imagine even more accurately designing an industrial or commercial factory. Even if a number of functional tools in the laboratory are integrated, which usually come from a number of manufacturers and have different capacities, operating the assembled mini mill is also not easy. That is why it is important to establish a complete line for the production of these pellets. The resulting pellet production can also be of two kinds, namely fuel pellets such as wood pellets and feed pellets such as leaf pellets, depending on the raw materials used.

And indeed on a commercial scale or large factory the pelletiser specification for fuel pellets such as wood pellets is different from the pelletiser for feed pellets. Pelletisers for fuel pellets such as in wood pellet production have a greater electric motor power about 3 times than a pelletiser for feed pellet production, for example for 1 ton/hour wood pellets need 150 KW while for feed pellets it is only 50 KW. In addition, the quality of the metal used for the production of the pelletiser is usually also different because the level of hardness of the raw materials is also different. Pelletiser is the main equipment or the heart of the process in pellet production, both fuel pellets (wood pellets) and feed pellets. Based on experience in the field, it turns out that there are many cases of failure of commercial wood pellet production due to errors in the selection of this pelletiser, namely the pelletiser for feed is used for wood pellets besides being not optimal, the machine life is short, even in a number of cases wood pellets are not formed so that the target production is not achieved. The main reason why this happened is because of being tempted by the price issue, namely the feed pelletiser is cheaper and in appearance it is also difficult to distinguish (especially the common people).

In this small capacity pellet production, only one type of pelletiser is used, because the main purpose is more on the qualitative aspect, not on the quantitative aspect. A number of process stages in the production of fuel pellets (wood pellets) are also very similar to the production of feed pellets, so the equipment used is also similar or even the same. This is mainly so that the price of the production unit is not too expensive. In commercial pellet production, ring die pelletisers are more widely and commonly used than flat die types. However, because the ring die pelletiser is more expensive even though it is close to the real conditions of the pellet industry, the flat die pelletiser is also sufficient for the purpose at this stage.

Feed pellets have a longer history than fuel pellets, especially wood pellets, namely in the 1920s when Purina Animal Nutrition, one of the largest animal feed producers in the world today. With this pelletization, the material is in powder form, unpalatable by livestock , different densities become easier to use and increase uniformity. This pelletization technique was quickly in great demand by many feed producers, so that in 1930 there were a number of feed factories specializing in the production of these feed pellets. World feed pellet production also far exceeds fuel pellets (wood pellets), which is in the range of 1 billion tons per year, while wood pellets are in the range of 50 million tons per year. Both have strategic functions in human life. Feed pellets as a food chain for humans are needed and their production continues to be increased. 

It is estimated that protein needs in 2050 need an additional 250 million tons per year, an increase of 50% compared to today. This is because according to the United Nations, the global human population is predicted to reach 9 billion people by 2050. The food sector is looking for a solution to the protein deficit due to protein demand per capita and population growth. Meanwhile, fuel pellets (wood pellets) are needed to save the earth from climate change. Wood pellets as carbon neutral fuel make it not increase the concentration of CO2 in the atmosphere which is a greenhouse gas that heats the earth's temperature. Decarbonization programs or substitution of fossil fuels for renewable energy, especially biomass fuel or wood pellets, continue to be improved throughout the world, as a reference you can read here and here. Energy plantations or legume plantations will be the solution to this problem, read in more detail here. 

 

In addition to pellet production (both fuel pellets and feed pellets) with a slight modification, namely replacing the pelletiser with a briquette machine, it can also be used for briquette production. This is because the production process is almost the same, the two technologies are the same, namely the biomass densification technology group. The use of these briquettes is also for fuel the same as wood pellets, but these briquettes can also be charred (carbonized) so that they become charcoal briquettes. The production of charcoal briquettes in this way produces better quality than the production of charcoal briquettes with charcoal as raw material and then added adhesive and pressed. This charcoal briquette product is commonly known in the market as sawdust charcoal briquette, the production of which does not require additional adhesive (binderless briquette).