Environmental Aspects of Wood Pellet Plant

When the process of wood pellets production do not pay attention to the environmental aspects, there will be a negative impact on the environment. Just like the usual plants always have an impact on operations for environment as well as wood pellet plant. The environmental impact was mainly noise pollution and air pollution. Engine or motor of the various units of production in the wood pellets plant is the main cause of the noise pollution. Vibration due to the large variety of equipment operational wood pellet plant also has implications for building damage around the location of the wood pellets plant. To minimize to overcome the problems then use of silencers or the selection of the motor which does not cause disturbing noise and vibration dampening mounting becomes important.

While the problems of air pollution, it is mainly caused by the exhaust gases from the combustion furnace for heating dryers, dust and VOCs (Volatile Organic Compund) of the dryer, dust and cooler from pelletiser. The dust pollution can be more severe if we process of grass type pellet.  A number of equipments have been developed to overcome this, as stated in the tables below:

 

Noise elimination and air pollution needs to be done to the acceptable norms. Considerations such as ease of operation, maintenance and the cost are some important things so that these devices can be applied and reached a level that is safe for the environment. Selection of plant location is quite far from the people settlement are also alternatives to reduce the cost of using the equipments for the elimination of pollutants.

Reed Pellets Untapped Potential

Although reeds is classified as grass types of entering grade 3 in biomass fuels due to its properties. But if the amount abundant and has not been utilized, it becomes a great potential to be processed into  pellets fuel. Thousands hectares of Reed such as in Borneo, Indonesia can be further processed for the production of pellets.

Due to high content of silica which makes abrasives that are not friendly to the metal with the high compression in densification that is needed special metal material that is more resistant for the ring die and roller. It also needed a thicker die to process material type grasses to increase compression (friction), the contribution to deliberate more lignin and finally to improve the quality product. The low of lignin content on the type of biomass also make necessary modifications in the process in pelletiser . The thickness of the die, pressing time, pressing temperature and pressure, will help improve the quality of the reed pellets without the need for additional adhesive. Mix with other ingredients (mix the material) that have greater lignin content such as sawdust will also improve the quality of the Reed pellets. The table below prosesntase a number of chemical compounds in the biomass.

Pellet production process of these grasses will generally produce more dust because its small  percentage of the lignin that need extra treatment in  the dust elimination system. Process operating conditions in pelletiser also affect the percentage of dust generated.

While the advantages of this material is that grass only has a low water content so that the drying phase can be minimized. In general, also the energy required for the production of pellets of the type of grass is lower than the sawdust material, woodchip and logs.

Market opportunities for grass type pellets is also wide open. Huge energy demand for various industries is an attractive market opportunities. The fuel quality requirements are not so high in a number of industries also make grass pellets well accepted, for example, for ceramic industries, bricks and so on.

Why Choose SRC Energy Plantations Than Palm Oil Plantations?

A number of the people plantations who produce fresh fruit bunches (FFB) was not able to be accommodated by the palm oil mill (POM), meaning that the ratio of the number of the POMs are not comparable with the number of palm oil plantations. Indonesia is the largest of palm oil producer (CPO=Crude Palm Oil) in the world with an area of oil palm plantations reach 10 million hectares by 2013. Palm oil productivity reached 27 tons / ha / year of FFB with a yield of CPO about 3.7 tons / ha / year, with the start of harvest after 4-year-old and productive period of about 25 years. With the average price of TBS IDR 1800/kg for every hectare would produce about IDR 48 million / year, a promising revenue from the plantation business course. But because all the FFB can not be processed due to the absence of plant it will not necessarily provide the desired benefit.

 

Energy plantation with SRC is an alternative for those who want to develop the plantation business investment is not so great. Plants such as calliandra and gliricidae very easy to grow, easy care, quick harvest, continue to be productive for about 25 years and fertilize the soil. Increasing the value added can be done with eg intercropping with crops. Unused land and marginal land could be pursued to the energy plantaion with thse plants. With the productivity of wood biomass around 20 tons / ha / year, with a price, let’s say, IDR 400/kg it will get a IDR 8 million / year for each hectare, it is far below of the economic aspect of palm oil plantation, but by the age of 1 year can be harvested, seeds and maintenance costs also very cheap, then it could be a consideration.

 The price of modern palm oil mill average price of IDR 4 M for every tonne of FFB / hour. With POM 45 tons FFB / hour capacity  it takes an investment IDR 180 M, a large amount of investment. As for the price of wood pellet mill capacity of 3 tons / hour range from IDR 5 M to become more affordable. Economic analysis of palm oil mill and wood pellet mill is almost the same, with the average ROI (Return on Investment) of 3.5 years.

Optimization The Pelletiser Perfomance

Carpet is a thin layer of material that is pressed, which are at the peak of the die surface. When the incoming raw materials into pelletiser it will be driven by the roller and forming carpet. The more materials put into pelletiser it will further add to the carpet. Carpet is then pressed into the die holes and produce pellets. So for material that can form a pellet, initially to be able to form a carpet.

All wood pellet production is a matter of reducing energy requirements and the degree of wear of equipment while simultaneously improving quality and productivity of the pellets. This is why the production of quality pellets require special skills. Setting between roller and die with a certain distance which is called the roller gap that is essential for the above purpose. Characteristics of raw materials such as density and bonding ability are other parameters that need to be considered. Roller gap can be set at a certain distance so that the pelletiser performance will optimal. Generally, gap 1 mm is the optimum condition, but the gap variation can be tried for the specific conditions of certain raw materials.

On hole die if we look deeper , it turns out is also not a form of cylindrical holes from the tip to the hilt . These conditions also deliberately designed so that the densification process can be optimal . If the shape of the tip is widened at the inlet of the die wear and missing then the quality of pellets produced will decline even not formed pellets . Comparison of length ( L ) and diameter ( D ) on the die hole according to the characteristics of raw materials will result in optimal performance . Selection of an appropriate metal material will make the pelleting process can be done economically . The quality of metal and metal working to die makes no domestic manufacturers are making in Indonesia. Another factor in has not many wood pellet producers in Indonesia may also be a factor in the reluctance of domestic manufacturers to make dies for wood / biomass pellets. But as the needs of wood pellet or pellet fuel increasingly skyrocketing then the above is possible.

Take a Look Closer at Wood Pellet

When we examine more closely to the wood pellet surface that we will look smooth, slippery and shiny. Even as smooth surface, slick and shiny that there are people who say that wood pellets are specially coated. Obviously this statement is groundless because especially not supported with a strong argument. Production of several  tons, tens to hundreds to thousands of tons per day of  wood pellets will produce the number of units very much. How about coating process? And how many substances are used so that the coating and still economically? Altogether these people can not give an answer.

Smooth surface, slippery and shiny is really due to the lignin in the wood tends to be resin that have plastic property. If mold is stretched and the temperature increased, the heat and absence of air condition in the shell will cause pyrolysis is characterized by outer skin darkened by carbonized.  This appears more clearly in the process of screw briquetteproduction, which also features on heater in the die so that the outer skin of the  briquette carbonized. 

 

The main components of biomass are cellulose compounds, hemiselulose and lignin. Each of these compounds has a different thermal decomposition temperature. Carbonization occurs when compounds of lignin in the biomass decomposes at a temperature of about 400 C. The table looks like this below.