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.
 

Biochar or Biocoal Production?

Biochar and biocoal production are basically one breath. Biochar production with full pyrolysis while biocoal with half/mild pyrolysis (torrefaction). The purpose of torrefaction/mild pyrolysis is to increase its energy content and make it hydrophobic so it is called biocoal. While the purpose of full pyrolysis is to produce stable biocarbon material so that it does not decompose in the soil for hundreds or even thousands of years and improve soil fertility so as to increase plant productivity (agriculture and forestry). 

Current biochar applications are mainly for agriculture and biochar production will produce excess heat, syngas and biooil as energy sources. While biocoal only focuses on energy. The benefits of biochar production are obtained from the sale of biochar, the sale of carbon credits and the utilization of by-products (full) pyrolysis. While the benefits of biocoal are only from the sale of biocoal itself.

The selection or development of a business will be related to business readiness (market, technology, investment, etc.) and other benefits, namely benefits in the social and environmental sectors. 

Why Is It Better For Palm Oil Mills To Use Pyrolysis Rather Than Combustion Furnaces?

The palm oil mill production process or CPO production always requires steam for sterilization, this means a boiler is needed. The heat needed by the boiler usually comes from a furnace with fuel in the form of mesocarp fiber and palm kernel shells. Apart from being used for sterilization, the steam is also used to rotate turbines and produce electricity. With continuous pyrolysis, heat for the boiler can be supplied from syngas and biooil products. Apart from that, pyrolysis also produces biochar as the main product and pyroligneous acid, which is a kind of wood vinegar. The last two ingredients will be very useful in palm oil plantations. Using these two fuels (gas and liquid fuel) will make the furnace produce cleaner smoke compared to burning solid fuel in the form of mesocarp fiber and palm kernel shells which is usually done up to now.

Many palm oil plantations are on acidic soils so the pH needs to be raised and biochar can be used effectively. The biggest operational cost for palm oil plantations is fertilizer and the use of biochar will increase fertilizer efficiency thereby reducing fertilizer input and saving costs. The application of biochar in palm oil plantations apart from improving soil quality thereby increasing the productivity of palm oil fruit or FFB (Fresh Fruit Bunch) is also part of the climate solution, namely carbon sequestration which receives compensation in the form of carbon credits. The carbon credits will also provide additional income for the palm oil company. Apart from that, pyroligneous acid can also be used as fertilizer and biopesticide.

The development of combustion technology is also increasingly developing, starting with the use of moving grates to reciprocating grates used to increase boiler efficiency. But the basic question is how profitable is the use of this technology for palm oil companies in overall? The use of the combustion furnace only increases the efficiency of the boiler, whereas the use of continuous pyrolysis in addition to sufficient boiler heat can also produce other benefits in the form of environmental and financial benefits. Environmental benefits from improving soil fertility conditions and minimizing fertilizer being leached or lost into the environment with the slow release fertilizer technique, for more details read here and also the income from carbon credits which is also big.

The application of biochar is for palm oil plantations, while biochar production is from palm oil mills, while the plantation division and mill division are two separate organizations within the palm oil company. The role of the general manager in particular is needed to handle this so that the company's big goals as a profitable, environmentally sound and sustainable company can be achieved. Factors in the form of maximizing profits, improving land and the environment, as well as being part of the climate solution with carbon sequestration will be a strong driving force for the use of continuous pyrolysis compared to combustion furnaces.

Fertilizer Savings in Palm Oil Plantations with Biochar and Compost from Biogas Waste

Although Indonesia is the largest CPO producer in the world with an area of ​​approximately 13 million hectares of palm oil plantations, but it is estimated that less than 10% have a biogas facility from POME (Palm oil mill effluent). Whereas by utilizing POME for biogas production, besides being able to be converted into electricity or heat, it also produces organic fertilizer in the form of compost and liquid organic fertilizer. The compost can be used as fertilizer in oil palm plantations, where the cost of fertilizer for palm oil operations is the highest cost component. It is estimated that every 10,000 hectares costs approximately Rp. 35.75 billion (around US$ 2.25 million) for fertilizer and for more details, you can read here. The use of compost will certainly reduce the need for fertilizer.

Palm oil utilization scheme for optimizing CPO production

Besides that, solid wastes such as palm oil empty fruit bunch, fiber and palm oil frond are also very potential for the production of energy (electricity and heat) and biochar. Energy production in the form of electricity and heat is by burning pyrolysis byproducts in the form of syngas and biooil into the furnace to heat the boiler. And because the syngas and liquid fuels used in the furnace, so that the combustion process is more perfect and clean emissions. Steam generated from the boiler will then drive the steam turbine and generator so as to produce electricity. Low pressure steam from steam turbine is then used for sterilization or boiling the fresh fruit bunches (FFB). While biochar will be used together with compost and chemical fertilizers to make fertilizer effective in the palm oil plantations so that it becomes a slow release fertilizer. Costs for fertilization are also expected to be significantly reduced, for example by up to 50% by this way. Although biochar is not a fertilizer, it has a function that makes fertilizer use effectively because it holds fertilizer nutrients from leaching, for example from rain water, also maintains moisture and so on.

PKS (palm kernel shell) can even be sold or exported. This is because previously or in general the palm kernel shells used to fuel boilers with fiber, have been substituted with products from the pyrolysis process namely syngas and biooil. The need for palm kernel shells for both the domestic / local and export markets continues to increase all the time. Palm kernel shells / PKS are environmentally friendly fuels because they come from biomass so they are carbon neutral fuels. The use of PKS as a fuel is widely used by a number of industries starting as a heat source for the drying process such as spray dryers in detergent and ceramic plants, boilers in food industries such as soy sauce factory, to power plants such as in Japan, can be read in more detail here. In the world of biomass fuel commodity trading, especially in the international market, PKS is the main competitor of wood pellets. Although the specifications are not much different, the price of PKS is also cheaper because it comes from palm oil mill waste and does not need complex processing units such as wood pellets. And basically with the scheme of utilizing palm oil mill wastes as above, it will maximize the profit from the palm oil mill or CPO mill. 

Energy Independent With Pyrolysis

A community even in remote areas can be energy independent as long as there is an energy source in the area. Biomass energy sources from plants are energy sources that can be obtained almost anywhere. The plant can be planted as a source of raw materials for the production of energy needed. Heat and electricity energy is energy that mostly needed, in addition to energy or fuel for vehicles as a means of transportation. Heat energy is mainly needed for cooking while electrical energy for various purposes in life. Pyrolysis is a technology that can meet the energy needs as above. The diagram below explains the application of pyrolysis to meet these energy needs:

Charcoal is a solid fuel product from pyrolysis. Although solid fuels such as charcoal, are not as practical and easy as gas fuels, the use of charcoal for cooking fuel has many advantages including being safe because it will not explode, smokeless, odorless, has a high calorific value and is an environmentally friendly fuel. While firewood in addition to causing a lot of smoke, smell, low calorie value also interfere with health. Today there are also many countries in Africa that use charcoal for cooking fuel. To make it easier to use and store, the charcoal can be made into briquettes. While fuel for vehicles such as diesel oil and gasoline can be produced from biooil. Vehicles for transportation can operate in the presence of these fuels. The availability of petroleum in Indonesia, which is estimated to be 10 years away, needs to be anticipated and prepared from now on. The current low price of petroleum makes petroleum exports less attractive, especially for Indonesia, which is currently a net importer of petroleum.

Charcoal stoves are widely used in Africa

In the future era when electric vehicles are widely used, electricity production especially for battery charging is prioritized. The energy source for electric cars as environmentally friendly vehicles should also be from renewable energy sources, for more details, please read here. Biomass is a carbon neutral energy source so it does not increase the concentration of CO2 or greenhouse gases in the atmosphere. Woody biomass from the energy plantation is the ideal raw material for the pyrolysis feed. Multipurpose energy plantations are the best energy plantation for this, so that in addition to sustainable production, it also provides other benefits, for more details about multipurpose energy plantations can be read here. Remote areas, especially those with large lands, will have the potential to develop these energy plantations, so that an energy independent community or region can truly be formed and sustainable. Areas in surrounding the palm oil plantations can also utilize biomass waste from palm oil mills and plantations such as palm oil empty fruit bunches (EFB), fronds, etc. for the pyrolysis feed. Indonesia is the owner of the largest palm oil plantation in the world with an area of ​​around 13 million hectares and 1,000 palm oil mills.