Cogeneration in Palm Oil Mills with Pyrolysis, Initial Steps in Biochar Production and Implementation

The analogy is like cofiring carried out in coal-fired power plants by mixing biomass fuels with a certain ratio as an effort to decarbonize the energy sector in power plants. While in palm oil mills, cogeneration with pyrolysis is an innovative initial step to enter the carbon negative era with the application of biochar, the main product of pyrolysis. And because all palm oil mills use biomass fuel for their mill operations, they are already based on carbon neutral fuel, unlike coal-fired power plants which are based on carbon positive fuels because they come from fossils.

Unlike cofiring which mixes coal and biomass fuels with a certain ratio and then burns them together in a furnace such as pulverized combustion, cogeneration is done by producing energy separately but the energy output is for the same use or especially the same boiler. This is done because the types of fuels may be different, such as solid fuels with liquid fuels or the technology for producing the energy is different. With this cogeneration, it means that not all energy is produced from one energy source or energy from cogeneration is a secondary energy source to meet total energy needs, and in the case of cogeneration in this palm oil mill, energy from combustion is still the primary energy.

Then why not just do full pyrolysis? It is easier, gradually for palm oil mills to adopt pyrolysis technology and its characteristics. Because (slow) pyrolysis aims to maximize solid / biochar, the by-products in the form of excess energy (syngas and biooil) as a source of boiler fuel, the calorific value is not as much as combustion which is indeed intended to maximize heat. Only about 1/3 of the excess energy contributes (cogeneration) as boiler fuel. In other words, if full pyrolysis is carried out directly, the amount of biomass as raw material for pyrolysis becomes 3 times greater or the pyrolysis unit becomes very large so that all palm oil mill biomass waste is used, and the mill cannot sell its palm kernel shells.

What are the benefits obtained by palm oil mills if they carry out cogeneration with pyrolysis for biochar production? Among the biochar products, it can save fertilizer use in oil palm plantations, overcome the problem of empty oil palm bunches (EFB) so that palm oil mills can achieve zero waste, palm kernel shells (PKS) that have been used for boiler fuel can be sold to increase income, the productivity of fresh fruit bunches (FFB) of palm oil increases, the application of biochar in palm oil plantations is also a climate solution (carbon sequestration / carbon sink) so that it can get carbon credit compensation and with good waste management, even zero waste and the application of biochar in palm oil plantations, palm oil companies will get a good image in terms of the environment and sustainability.