There are 3 types of solid waste in palm oil mill, namely fiber, palm kernel shell and empty fruit bunch. The average amount of the three waste : 13.5% fiber, 5.5% palm kernel shell (PKS) and 23% EFB. The greater the CPO production capacity or the processing of FFB the greater the waste produced. Fiber and shell are commonly used for fuel by being burned directly for electricity production and steam for the production process of palm oil mill or CPO production. But with this way there is not much to gain except electricity, steam and ash as its residue. While a more beneficial way that is by replacing the usual combustion system (direct combustion) for steam and electricity production with continuous pyrolysis. Why with continuous pyrolysis can give greater benefits ? That is because with continuous pyrolysis besides being able to produce electricity and steam as well as on regular combustion also produced charcoal. Charcoal can be used for soil fertilizer media in palm oil plantation itself and as an export commodity that is palm kernel shell (read the problem of palm kernel shell at this time here).
While EFB can be processed into compost or fuel such as pellets and briquettes, some even use EFB to make paper, or just taken the ashes with burned because it is rich in potassium. Continuous composting is also more efficient, faster and cleaner than composting in batches. The compost can then be used in conjunction with charcoal so that its use to improve soil fertility optimally. Burning the EFB for its potassium-rich ashes is pretty much done by today's palm oil mills. It is chosen because it is easy, cheap and fast. But for use as fuel there is another option that is to make it into pellets or briquettes. One of the EFB processing scenarios can be read here. The choice of EFB processing above depends on the vision of the palm oil company itself, if its vision is more to increase productivity of palm oil plantation and CPO production even to organic plantation then composting is more suitable to choose, moreover EFB also very wet when out of palm oil mill. Whereas if their vision to get more profit or additional income faster by processing it into energy or fuel such as pellets and briquettes would be more suitable.
Why is charcoal preferred for soil fertility improvement? Is charcoal better than burning ash in that case? The process of making charcoal through the process of pyrolysis or carbonization with temperatures ranging from 400-500 C so that a number of ash chemical compounds, such as potassium still in the solid product in the form of charcoal or not lost during the conversion process, so that can still be used for plant nutrition. Charcoal also has a lot of micro pores to hold soil moisture, microbial house and keep the nutrients or fertilizer because the plants washed out ( leaching) due to the flow of water like rain. Rainfall in Indonesia is quite high ie 2700 mm / year or three times higher than the world rainfall ranging around 900 mm / year. Only two of our neighbors are Malaysia (2,875 mm) and Papua New Guinea (3,140) whose rainfall surpasses Indonesia. Charcoal also makes fertilizer or nutrient plants release slowly (slow release fertilizer) to be absorbed by plants. More and more use of charcoal in the palm oil plantation will have a positive impact on the productivity of Palm oil. If every hectare of palm oil plantations requires 20 tons of charcoal then the need for charcoal is also great. We take the example with the area of 100,000 hectares of palm oil plantation then the overall need for palm oil plantation reaches 2,000,000 tons. This can only be done gradually as CPO production activities. A number of studies have even stated that with the use of charcoal, the need for fertilizer can be reduced or saved up to 50%. That's because with the use of charcoal, the washed water plant nutrient in the soil can be minimized. Of course a happy thing. Moreover, the charcoal will survive hundreds of years on the ground so that the benefits last long. Such characteristics make charcoal superior to ash. Ash with various ash-chemical compounds such as potassium can be directly absorbed by plants so that it can be used as fertilizer until the nutrients in the ash are exhausted. Therefore conversion of solid waste from palm oil mill to charcoal is preferred.
Why choose the process of pyrolysis to process solid waste of palm oil mill ie palm kernel shell and fiber by replacing direct combustion process? Why not choose gasification to process the waste? In the gasification only produced a little charcoal so it is not sufficient. Technically, the palm kernel shell and fiber can be mixed as well as when fed as fuel in direct combustion, then fed to pyrolyser or carboniser, then charcoal is separated, ie charcoal from fiber and charcoal from palm shells based on material size difference. Small-sized charcoal from fiber like powder so it is suitable and can be directly used for plantations, while the larger-sized palm kernel shell charcoal such as granules. The palm kernel shell charcoal can then be used for fuel or other industrial raw materials such as activated charcoal.
The processing of solid waste of palm oil mill namely, palm kernel shell and fiber will give more benefit if using continuous pyrolysis technology. While EFB can be made compost or solid fuel such as pellets and briquettes. The charcoal applied to the plantation will improve soil fertility, as nutrients are more available and are not easily discharged or washed out due to water flow. There are more than 600 palm oil mills in Indonesia and nearly half of the world's CPO demand is supplied from Indonesia (23 million tons of CPO annually) and palm oil plantation area around 9 million hectares, so efforts to maintain the sustainability of the business are essential. Solid waste processing of palm oil mill in the form of palm kernel shell and fiber with pyrolysis and EFB for compost production and compacted (densification) into pellets and briquettes, necessary and important for various benefits as mentioned above.