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.

Case Study India: Priority of Biomass Pellet Production Over Biomass Briquette

There are dozens of biomass briquette machine manufacturers in India and almost all of these machine manufacturers use mechanical press technology for the production of these briquettes. With this technology, briquettes will be formed due to mechanical press such as repeated strokes every minute (about 220 strokes per minute). This briquette machine manufacturer industry has also existed for decades in India so that biomass briquette products have also been widely known in India. Technically, there are actually 2 other technologies for the production of biomass briquettes, namely screw press and hydraulic press. Based on the briquette production technology, the briquette product output is also slightly different, for more details, read here.

The Indian government launched a decarbonization program at their coal power plants, recently, namely on October 8, 2021 which ordered the use of 5% to 10% biomass pellets for cofiring at all power plants and took effect in October 2022 or one year is the target time set. For example, in the early stages, the Indian government targeted only 5% for the cofiring ratio in their coal power plants, where the 5% figure when translated into biomass pellet production would reach around 50 million tons of biomass pellets per year. A very large number especially with a very short target time. And with a cofiring ratio of 5%, coal power plants also do not need to modify their equipment even though the biomass pellets used come from agricultural wastes, whose quality is below that of woody biomass.

With the number of power plants reaching about 900 units with an average consumption of 50 thousand tons of biomass pellets per year or a total of almost 50 million tons per year, so that a biomass pellet factory with a capacity of around 5 thousand tons / month seems to be suitable, and even if each factory supplying one power plant, the need for a biomass pellet plant will also be the same as the number of power plants, which is 900 units. A huge amount.

Production of biomass briquettes or biomass pellets?
In India, biomass briquette is indeed more popular than biomass pellets, but for the world level pellets are much more popular than briquette, even in 2021 alone, the need for pellets for global power generation alone is estimated to have reached 23 million tons. In addition, the production or pellet factory in general is also larger than the briquette factory. There are many pellet factories with a capacity of 5 thousand tons or even 10 thousand tons per month, while for briquettes it is very rare for a biomass briquette factory to have a capacity like the pellets above. Pelletisers for pellet production for commercial capacity have a capacity of 3 tons/hour or more, while briquette machines are generally less than 2.5 tons per hour, even for the screw press type the average machine capacity is only 300 kg/hour. Technically, even though they are both products of biomass densification technology with the difference that the size of the briquettes is larger than pellets, the production of briquettes is easier than pellets. 

The driving force from the business side makes biomass pellet production more attractive, especially because of its need as cofiring fuel in coal power plants as part of the decarbonization program. The need for biomass pellets can be a driving force for the production of biomass pellets or in general, namely the economy in various regions. The program should also be able to provide three benefits at once, namely environmental, social and economic. In addition, because briquette products are mainly used for boilers in industry, while pellets are for power generation, both of them also have their own market segments so that there is no market competition.

What about the Briquette Machine Manufacturing Industry?
Dozens of industries producing biomass briquette machines should now see this as an opportunity so that they can respond to it. These industries can adapt by creating a new line of business, namely helping the manufacture of a biomass pellet factory. Technically, the biomass briquette production line with biomass pellets also has many similarities (both use biomass densification technology) with the main difference being the pelletiser and briquetter. A number of equipment that can be made themself will reduce imported machines. Pelletisers are almost certain to be imported, so the selection of pelletisers as the heart of the pellet production process must be of high quality so that the pellet production target can be achieved. In the production of large capacity pellets, a number of equipments come from a number of providers, as is common in wood pellet factories with a more detailed explanation here.

In the long term, the goal is to minimize import spending, and even 100% can be made or fabricated by themself. This effort will usually take longer because the complexity of the pelletiser is higher than that of the briquetter. These briquette machine-producing industries can also cooperate with machine manufacturers in Europe who are more experienced and proven with pellet production as an effort to accelerate the transfer of the technology. Within one year as the target was set, it is very difficult to do this, so the practical effort is to buy a 100% complete line from a proven vendor, or sort out a number of equipment that can be produced yourself as above and gradually substitute the imported equipment. This is because achieving the production target for the decarbonization effort is a priority.

In conclusion, at this time India has to maximize efforts to accelerate the construction of biomass pellet factories to achieve this target. However, 1 year to achieve this target is very difficult. With these conditions in the future, it is possible that power plants in India will import biomass fuels such as wood pellets and PKS (palm kernel shell) to meet their needs. With the planned cofiring ratio, which is the lowest target of 5%, the need for biomass pellets reaches around 50 million tons, if only 2% of the biomass fuel needs are imported, both PKS and / or wood pellets, it will reach 1 million tons, a fixed amount still quite big.

Die and Roller in Pelletiser

Pelletiser is the heart of the production of wood pellets. The quality and quantity of products of wood pellets is mainly determined by this equipmnent. Quality equipment of pelletiser itself is determined by the ability to produce wood pellets according to specifications or international standards. More and more product of wood pellets are produced or the longer lifespan (life) of pelletiser it indicates good quality. After going through the boundary of the capacity or useful life of the pelletiser to be replaced because it is no longer effective when continuously used. As a benchmark cost for this pelletiser range from Rp 40-75, -/kg wood pellets, including good category.

Pelletiser which is the principle of compression or suppression of material by the roller into the mold (die) to form wood pellets. The high friction on the roller and die on the raw materials and the heat causes the temperature of the metal wear faster. The greater the friction the more dense wood pellet produced  or hard but metal material of pelletiser wear faster. The quality of the metal material in the die and roller of pelletiser and pelletiser design itself contributes greatly to the performance and life of the pelletiser.

Currently there are two kinds pelletiser commonly used in the production process of wood pellet flat die and ring die. The flat die design simpler, commonly used for woodpellet production in small capacity, its history  adopted from animal feed pellet machine. While the type of ring die is a more advanced design, the technique of making it more difficult than further development of the type flat die and commonly used  in production of wood pellets medium-large scale.