Increasing Energy Efficiency in Palm Oil Mill Operations Using Pyrolysis

Energy utilization in the form of steam production which is then used for electricity production through steam turbines and generators, as well as the use of steam for steamming (sterilizing) fresh fruit bunches (FFB) are the main things in palm oil mill operations. This is because the need for electrical energy to power various mechanical equipment in the mill comes entirely from this electricity production. Electricity and steam for industrial processing are grouped under the utilities that support that industry. Meanwhile, in the sterilization process or the boiling of FFB, steam besides stopping the development of FFA (free fatty acid) and facilitating the threshing will also facilitate the CPO extraction process and processing the kernel (palm kernel). To produce steam and electricity, of course, energy is needed, namely heat. Steam is produced by the boiler in the form of superheated steam to drive steam turbines and generators to produce electricity and then steam from electricity production or low pressure steam is used for steamming (sterilization) of FFB.

The water after being treated so that it becomes BFW (boiler feed water) is then used for the production of steam and electricity. Heat energy to produce steam can be reduced in such a way with the use of a pyrolysis process (which means that it is not ordinary combustion), so that the heat requirement for the boiler furnace is getting smaller. The pyrolysis condenser will produce hot water so that it becomes preheating for the boiler. In pyrolysis a condenser is used to separate bioil and syngas (uncondensable gas). Preheating from the condensation process of the pyrolysis unit will then go to stage 2 preheating in the economizer of the boiler unit. Thus the temperature of the water entering the upper drum on the boiler is high enough, and the heat requirement to become superheated steam will be reduced. The palm oil mill uses a water tube type boiler as is commonly used in large industries and not a fire tube which is in the form of a shell and tube type heat exchanger with the tube submerged in water so that it does not overheat. In a water tube type boiler, it consists of an upper and lower drum (mud drum) which is connected to a pipe. The lower drum and water tube are fully filled with water, while the upper drum is only partially filled. With this arrangement, steam will pass through the mechanical separator on the upper drum, flow to the superheater and exit the boiler. Efficiency is the key word in production, including the use of energy in the production process of CPO or palm oil mills. The rule of thumb is an increase of 10 C in BFW is equivalent to increasing 1% boiler efficiency.

Typical of water tube boiler

Excess energy from the pyrolysis process should be used for fuel or energy sources in the boiler furnace. The use of excess energy from pyrolysis will also produce environmentally friendly flue gas emissions because the combustion of liquid and gaseous fuels will be cleaner than solid fuels. In this way, the palm kernel shell, which has been used for boiler fuel, can no longer be used. All these palm kernel shells or PKS can be sold directly and even exported to Japan and Korea. Of course, be a separate source of additional income. Palm kernel shells or PKS are competitors for wood pellets in the global market because they have many similar properties, but because palm kernel shells come from waste or palm oil mill sideproducts, the price can be cheaper, more information can be read here. The use of slow pyrolysis for biochar production is the best option compared to similar technologies such as fast pyrolysis and gasification, more details can be read here. Palm oil mills or companies will get a lot of benefits from biochar production, for more details can be read here.