Premium Wood Pellet Production From Plywood Factory Waste

Indonesia's plywood or plywood production is estimated to be more than 10 million cubic meters annually, which is produced from hundreds of plywood factories, even Indonesia once dominated the world's wood industry in the period from 1980 to 1995. 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, namely Banten, Papua, Central Kalimantan, South Sulawesi, Riau and Jambi. Most of the plywood is for the export 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 the national plywood production. The potential for this waste is quite large and has great potential to be processed into premium grade wood pellets. Why is wood pellet an option and why does it have to be premium grade? Wood pellets are the choice for the solution to the plywood waste problem because in addition to an easier production process, machine investment is also cheaper. This is because the wood waste from the plywood factory is dry, so it does not require a drying process. The dryer is not only quite expensive but also the operational costs. Premium quality is also possible due to the low ash content, because the wood for the plywood production has been debarking so that the ash content can be reduced to below 1%.

Size reduction / down sizing is the first thing that needs to be done with the plywood waste. After the particle size is appropriate, which is the size of sawdust (~3-5 mm), then the wetting process is carried out until the moisture content reaches about 10%. This is because the wood waste from the plywood factory is usually too dry, with a moisture content of 4-5% so that it does not meet the requirements for pelleting. Raw materials that are too dry make pellet gluing not optimal, so that pellets become brittle and even pellets are not formed at all. The wetting process is carried out with a water sprayer to reach the moisture content level. After the water content reaches about 10%, then the raw materials enter the pelletiser to be pressed or molded into pellets.

The premium grade wood pellet market segment is different from standard or utility grade wood pellets according to the table above. The use of premium grade wood pellets is for heating, especially in winter in countries with four seasons. The main reason for using premium grade wood pellets for this purpose is the very low ash content. With a low ash content, ash cleaning becomes less frequent. In general the production of premium grade wood pellets is more difficult than standard or utility grades, but especially in the plywood industry with the conditions of the raw materials as above, it is much easier and more prepared for the production of premium grade wood pellets. A golden opportunity for those who realize and understand it.

Debarking from Energy Plantation Wood, Is It Necessary?

Debarking machine

Wood pellet target market is an important thing that needs attention. If the power plant is the main market for wood pellets, the quality standard of wood pellet products follows the technology used by the power plant. Meanwhile, if wood pellets for households who want premium quality, wood pellets that are produced also follow these quality standards. The wood pellet market for electricity generation needs large, different from the wood pellet market for households that are sold in small packages or the retail market. Electricity generation technology also needs to be monitored so that all wood pellets produced can be absorbed. Pulverized and fluidized bed combustion technology is the technology most widely used for electricity generation. In pulverized combustion technology generally wood pellets cannot be used 100% (except with a number of modifications), while fluidized bed technology can use wood pellets or biomass pellets from various raw materials.

What is debarking? Why do need debarking? Debarking is the separation of bark from log, with the aim of reducing ash content. That means that if the ash content of the log with the bark can be accepted by the user, of course debarking is not necessary. For power plants usually can accept wood pellets up to 2% ash content for standard pellets and 6% for utility pellets. Meanwhile, if the user wants a wood pellet product with very low ash content, premium pellet (less than 1%), then debarking must be done. The wood species used also affects the ash content. Almost all energy plantations use fast rotation plants and coppice such as gliricidia with ash content of more than 1% so that it is more suitable for electricity generation and do not need debarking.

CFB Powerplant in Japan

Another thing to note is ash chemistry. The potassium and chlorine content in the ash is a critical point that needs attention. Fast rotation plants in general have a high potassium content than wood biomass in general. This makes the use of power plants in particular pulverized combustion increasingly limited to cofiring applications. Whereas in fluidized bed combustion because the operating temperature is lower then it can be tolerated and is considered not to cause problems. This means that wood pellets from energy plantation wood are compatible with biomass power plants with fluidized bed technology and can be used for cofiring with a certain percentage of pulverized combustion.

Origins of the Wood Pellet

History of the manufacture of wood pellets begin from the energy crisis of oil in the 1970s. Wood pellet making technology itself is adopted from animal feed/fish pellet technology  that had already been applied.  Along with the development of various technological modernization in line with the characteristics of raw materials, product specifications or market demands according to international standards, production efficiency and capacity of the plant to meet market needs. Efforts to create alternative energy from renewable sources  with several quality improvements of raw material into the solution at that time. After the oil crisis of the 1970s ended the production of wood pellets decreased. But when the problem of global warming, climate change and efforts to increase the added value of woody biomass and the rapid depletion of fossil fuels began in the 1990s finally wood pellets again received great attention.

Woody biomass in particular is said to be a source of alternative energy that can be renewed only if the production is done in a sustainable manner. Forest plantations or energy crops is an attempt to sustainable production of biomass sources in addition to the utilization of wood wastes from various industrial timber that must also be traced if from legal sources. Sawdust in particular is the best raw material for the production of wood pellets, but because of its availability is usually not a big plus if collected from a number of sawmill waste for example, and so much demand that should be observed when actually be used for the production of wood pellets. 

The wood logs are part of a plant or tree are best to produce pellets. If the premium quality woodpellets (pellets Class A1) produced,  the debarking process must also be done to minimize its ash content. While part of trees or other plants that have a higher ash content so it can not be used for the production of premium quality wood pellets. Wood pellets have the best quality lowest ash content and high calorific value and are generally only used for the home heating in some European countries, the U.S. and Canada. While wood pellets with a lower quality than that its use in industry. 

Log wood for premium wood pellet feedstock after debarking

In contrast to European countries and the U.S. are generally using wood pellets for domestic consumption as heating, in Asia generally digunakansebagai wood pellet fuel or power generation industries. The differences in consumption patterns due to climatic conditions, among others, as a result of its geographical location and the awareness of the environmental impact.  Various advantages of wood pellets for industrial and domestic applications and a wide range of driving factors on environmental issues, climate change, global warming and the economy makes it increasingly massive demand for the commodity.