Palm kernel shells (PKS)

Palm Nut Shells or as they are officially called Palm Kernel Shells (PKS) is a product coming from  South Eastern Asia. Also quite a lot of PKS is avaliable in Africa (Ghana). PKS are crushed into the  particles of  10-20 mm  size. Product  have moisture content about 11-12%. Ash content is  1,65%, which is  generally very low for biomass and  also lower than in Palm Kernel Expeller. Chlorine is  0,054% which is much lower than in  PKE. Sulphur is 0,13%  which is also lower than  in  PKE. Net calorific value is 17,25 GJ per mt which is higher than in PKE and is comparative with wood pellets.   To prepare PKS at the production sites in the country of origin in a milled  or peletized form  is unlikely to be economical. One of the negative sides of this material is rather high durability of the PKS which makes it impossible to use the product in coal fired power plants (milling problems). For example Durability Index (hardgrove index) of the sunflower husk pellets is 18. Durability index of olive cake is 20 (the harder product, the lower durability index). Durability  index of almond nut shells is 17. Durability index of the olive  stones ,which due to their  hardness are not used in UK power plants as biomass, is 15. Durability of PKS is simmilar to olive stones. Products with this kind of durability index are creating problems for coal fired power plant mills which are disigned for more soft product - coal. That is why PKS is mostly used at biomass dedicated power plants. A lot of PKS goes to biomass plants on the East coast of Italy. Also have to be  counted  that moisture content of  the delivered to the unloading port PKS could be higher than declared, as the product maybe hold in piles under the open sky even during the rain season.