Palm Kernel Oil (PKO) and Coconut Oil (CCO) for Bio-Avtur (SAF)

Bio-avtur or SAF (Sustainable Aviation Fuel) will be the only decarbonization scenario in the aviation sector for the next few decades. The three leading production processes for SAF production are HEFA, FT and ATJ. And of the three processes, the HEFA process is the most efficient and most competitive at present, predicted to survive until 2030. The raw materials or feedstock for the HEFA process are mainly vegetable oil, used cooking oil, animal fat and so on. The HEFA process has also been approved by ASTM for use as aviation fuel (bio-jet fuel) based on ASTM D7566-14. In 2011 the latest version of the standard was published that allows up to 50% of HEFA aviation fuel products to be added to conventional jet fuel or petroleum-based fuel (avtur). ASTM itself, as an entity, does not have the authority or drive the development or qualification process of a new SAF technology, but only creates a framework, process, and repository that is the basis for the industry to create test methods, specifications, classifications, guidelines, and practices for their own needs.

Bio-avtur or SAF must have characteristics similar to conventional jet fuel so that it can be used anywhere in the world. Jet A fuel is primarily used in the US and jet A1 fuel is used in the rest of the world. The fuels are interchangeable. The main difference between the two types is that Jet A1 has a lower freeze point (-47oC, vs. -40oC) and usually has a static quenching additive (SDA) added to help reduce static buildup in the fuel during flight. Jet A1 is the fuel of choice for intercontinental flights. Given the volatility of jet fuel, the preferred components are hydrocarbons in the C10 to C15 paraffin range. Furthermore, to meet the freeze point specification (-47oC), these paraffins must be highly branched to achieve such a low freeze point. This means that bio-avtur or SAF must have carbon atom bonds or C bonds in the C10-C15 range, and in this range palm kernel oil (PKO) and coconut oil (CCO) are most suitable due to their high lauric acid composition which consists of 12 C atoms.

HVO / HEFA - SPK (Hydro-processed Esters and Fatty Acids-Synthesized paraffinic kerosene) is a renewable paraffin with combustion properties similar to other renewable paraffins such as Fischer-Tropsch fluids, produced by biomass gasification and chemical synthesis. HVO / HEFA can be produced in dedicated facilities producing 100% HVO, or it can be co-processed with fossil fuels in petroleum oil refineries. In co-processing, a bio-based feedstock of typically 5-10% is blended with the fossil feedstock. The HVO / HEFA process in addition to renewable diesel (which is different from biodiesel – FAME) can also be modified to produce bio-avtur / SAF for jet fuel applications. AltAir Fuels supplies HVO / HEFA based SAF and produces approximately 13 million liters per year.

HEFA is produced by hydrogenation and hydrocracking of vegetable oils and animal fats using hydrogen and catalysts at high temperature and pressure. In this hydrotreating process, oxygen is released from the feedstock consisting of triglycerides and / or fatty acids. This will produce straight chain hydrocarbons (paraffins) with various properties and molecular sizes depending on the characteristics of the raw materials and the operating conditions of the process being carried out. With the high lauric content in palm kernel oil (PKO) and coconut oil (CCO), the yield will be high because the oil content is in the bio-avtur range, namely C10 - C15. This is different if you use vegetable oil with a longer carbon chain, such as CPO, calophyllum inophyllum oil or canola oil. If you use vegetable oil with a long chain, the yield will be small and an extra cracking process is needed to increase the yield of bioavtur or SAF.

This conversion usually goes through two stages, namely hydrotreatment followed by hydrocracking/isomerization. This hydrotreatment process is usually carried out at a temperature of 300 -390 C and for triglyceride treatment, propane is usually produced as a by-product. The more hydrogen is added, the less propane is produced. The final product of the straight-chain hydrocarbon can be adjusted according to the type of fuel, for example for bio-avtur or bio jet fuel or SAF, namely by isomerization and the cracking process. The hydrogen used in HEFA production currently mostly comes from fossil sources or blue hydrogen. The catalyst for this can be a simple refinery hydro-processing catalyst. This catalyst can be adjusted to isomerize the paraffin chain to lower the melting point of the product. If necessary, a second isomerization stage is used to carry out this task in order to achieve the required jet fuel cold flow properties, namely Jet A or Jet A-1.

Currently, Pertamina (Indonesia's state-owned oil company) has succeeded in producing bio-avtur or SAF from palm kernel oil or PKO processing, namely refined bleached deodorized palm kernel oil (RBDPKO) called bioavtur J2.4 or containing vegetable oil ingredients in the form of RBDPKO 2.4%. The production of this bioavtur is carried out through the Hydrotreated Esters and Fatty Acids (HEFA) co-processing method and has a capacity of 9,000 barrels per day. The J.24 bioavtur has successfully undergone commercial flight tests on a Boeing 737-800 NG aircraft owned by PT Garuda Indonesia (Persero) Tbk. (GIAA) on October 4, 2023. And for the future, apart from the quantity aspect, namely the portion of vegetable oil (PKO) is larger, even the use of other vegetable oils such as coconut oil (CCO), CPO oil, calophyllum inophyllum oil and so on, it is also hoped that the quality of bioavtur will also improve. In addition, there are also plans from other institutions, namely the production of biovatur or SAF from coconut oil in collaboration with Japan.

In the aviation fuel industry, ASTM serves as the international standard for jet fuel quality, and plays a critical role in ensuring the safety, quality, and reliability of Sustainable Aviation Fuels (SAF). ASTM establishes requirements for criteria such as composition, volatility, fluidity, combustion, corrosion, thermal stability, contaminants, and additives, among others, to ensure that fuels are compatible when blended. ASTM International (American Society for Testing and Materials) is an international organization that develops technical standards for a wide range of materials, products, processes, systems, and services. Jet fuels must meet stringent quality specifications to be eligible for use in the aviation industry.

There are several ASTM standards related to this jet fuel, namely first, ASTM D1655: This is a conventional jet fuel specification that establishes requirements for Jet A and Jet A-1 produced from petroleum. This specification has been used globally by the aviation industry since 1959 to ensure the availability of safe and consistent jet fuel for all aircraft. Second, ASTM D4054: This ASTM standard practice defines the scope of fuel, rig, and engine property testing that should be considered when evaluating new synthetic jet fuels. This practice also describes the overall evaluation process and the important role of engine and aircraft manufacturers in ensuring a good jet fuel safety record is maintained with these new fuels. Third, ASTM D7566 Pathway: As per ASTM D4054, the pathway includes definitions of synthetic jet fuel blending components as defined by: permitted feedstocks; conversion processes and their attributes; and the final characteristics of the pure components. All of this is detailed in both the body of D7655 and its Appendices. The pathway will also define blending requirements.

In order for a new SAF production line to be included in D7566, it must undergo extensive testing to determine the maximum blend ratio with conventional jet fuel and demonstrate that the blend is suitable for its intended purpose. This procedure is outlined in ASTM D4054, ‘Standard Practice for Evaluation of New Aviation Turbine Fuels and Fuel Additives’.

Each batch of jet fuel needs to be certified before it can be used. While conventional jet fuel is certified as D1655 fuel (or a derivative), pure SAF is certified to the stringent specification requirements set out in Appendix D7566 which relates to the SAF production line. D7566 certified SAF is blended with conventional jet fuel to the maximum allowable blend ratio. The blended SAF is then certified to the D7566 blend requirements, and thus automatically receives D1655 certification, making it fully Jet A/A-1 compliant (‘drop-in fuel’) and ready for use in existing jet fuel infrastructure and equipment. In short, ASTM is vital to the aviation fuel industry as it is the basis for international standards for the quality of jet fuels, and SAF in particular.

Energy Plantations Energy Sources for All Time

 "Allah who makes fire for you from green wood, then you kindle (fire) from it." (QS. Yaasin (36): 80)

The sun was created by Allah SWT as the main source of energy for humans and living things on earth. It takes about 8 minutes for sunlight to reach the earth and is converted by plants into a food source so that it can be consumed by animals and humans. Humans also get food from animal sources. The more sunlight, the more can be converted by plants through the process of photosynthesis. Without the sun, plants die, animals die, humans die so that there will be no life on earth. Fossil fuels are essentially a source of energy from plants and animals in the past. Mining and use of fossil fuels will release a number of greenhouse gases (GHG) which increase the earth's temperature which at a certain level is dangerous for the earth's population itself. Efforts to overcome this are by using non-fossil energy and renewable energy so as not to contribute to increasing the concentration of GHG in the atmosphere which increases the earth's temperature.

From plants or trees can be directly used as a source of energy or fuel, namely firewood. Derivatives or energy products from plants are also very diverse and can meet all human needs, both energy in the form of solid fuels, liquid fuels and gas fuels. The production of firewood, wood chips, wood briquettes, sawdust, torrified biomass to charcoal are a number of solid fuel products. While the production of biooil, bioethanol, biodiesel, renewable diesel / green diesel, and bioavtur / bio jet fuel are a number of liquid fuels. And biogas and bio-syngas are gas fuels that can be produced from the original material in the form of plants.

A number of conversion techniques based on physics, chemistry and biology are needed for the conversion. The use of appropriate plant species is also needed to facilitate the conversion, for example for the production of solid fuels, biomass sources such as wood are needed, while if the target is liquid fuel, then the type of oil-producing plants that need to be pursued. Conversion from solid fuels to liquid or gas fuels can also be done but in general the longer and more complicated the process, the more expensive the production costs will be. But still, energy plantations are the basis for all of that.

Popular and fairly easy biomass processing is to make wood chips with size reduction then wood pellets and wood briquettes through biomass densification. Furthermore, to convert sugary biomass into ethanol with fermentation and azeotropic distillation, convert lignin biomass (lignocellulosic biomass) into ethanol with enzymatic hydrolysis reactions followed by fermentation and azeotropic distillation. Converting woody biomass into fuel with a thermal process can be burned directly or if you want to make charcoal, concentrate the fixed carbon, namely by pyrolysis or carbonization, and if you want to maximize liquid products / bio-oil / pyro-oil, namely by fast pyrolysis and if you want to maximize gas products, namely by gasification. And so that the characteristics of the biomass are like hydrophobic coal, the torrefaction or mild-pyrolysis process can be carried out. Torrefaction and densification are usually carried out together to optimize the biomass fuel product.

With gas to liquid (GTL) namely the gasification process and followed by the Fisher - Tropsch process, bio-ethanol, biodiesel and bioavtur / bio jet fuel can be produced. While from groups of plants that produce oil such as palm oil, biodiesel can be made especially with the transesterification or estran (esterification plus transesterification) process. Even used oil or used cooking oil / used cooking oil and miko (minyak kotor) / dirty oil or PAO (palm acid oil) can also be used for biodiesel / green diesel or further processed into bio-jet fuel / bio-avtur with the HVO / HEFA - SPK (Hydro-processed Esters and Fatty Acids-Synthesized Paraffinic Kerosene) process.

So basically, biomass from trees can be processed into various forms of energy or fuel needed by humans. In addition to being used directly as a heat source, this energy can also be converted into mechanical energy or electrical energy, for example biofuel-fueled vehicles to biomass power plants. So the source of energy throughout the ages stored in plants is this biomass as stated by Allah SWT in the verse above and there is no doubt whatsoever about it. Indonesia as a tropical country is a "heaven" for the production of biomass because of the rays of sunlight throughout the year and adequate rainfall and extensive land. The storage of energy in plants from sunlight is also likened to a battery that can be used anytime and anywhere for more details read here.

Another important thing to note for the creation of energy plantations or biomass plantations is the status of the land used. The land must not be from deforestation or land conversion (land use change) that damages the environment. Industrial plantation forests (HTI) that are in accordance with their designation can be used as energy plantations. In addition, biomass for producing energy can also be cultivated on critical land, or referred to as 'unproductive' land. The Indonesia Ministry of Environment and Forestry (KLHK) estimates that critical land in Indonesia in 2016 was 24.3 million hectares (Times Indonesia, 2017). This is a very large area, and overall Indonesia's territory is large enough to provide biomass for renewable energy production.

PAO and UCO Become Bio-Jet Fuel

Decarbonization has entered all lines including the air transportation sector. Aviation fuel must also gradually shift from fossil fuels to sustainable renewable fuels. However, decarbonization in this sector is still slow, namely currently only around 0.01% of the use of sustainable renewable fuels or SAF (Sustainable Aviation Fuel) globally for these aircraft. These barriers include technological maturity or technological readiness, certification for SAF conversion or production process routes, scale up and commercialization, price gaps with fossil fuels, and competition with biofuels in the land transportation sector. The Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA) has initiated a reduction in GHG emissions for global aviation. Using the 2019 baseline, it is estimated that around 2.5 billion tonnes of CO2 emissions need to be offset / reduced in the 2021-2035 period to achieve carbon neutral growth. CORSIA also plans its implementation in three phases, namely the pilot phase in 2021-2023, the first phase in 2024-2026 and the second phase in 2027-2035. Participation of member countries is voluntary in the first two phases (2021-2026) and mandatory in the 2027 phase and beyond, except for the least developed countries, small developing countries and landlocked countries.

Until now, HVO / HEFA - SPK (Hydro-processed Esters and Fatty Acids-Synthesized paraffinic kerosene) technology using vegetable oil including waste oil is the only technology that is most ready for the conversion or production of SAF. Currently, the technology readiness level (TRL) and feedstock readiness level (FRL) are at level 9, meaning that it is the most ready among other conversion technology routes. One of the advantages of HVO technology is the flexibility of using various feedstocks / raw materials so that waste oil such as PAO or mico from palm oil mill ponds and also used cooking oil or used cooking oil or UCO are also very potential to be converted into SAF with HVO technology. But in fact, even though HVO technology can directly produce SAF, most of the HVO technology is used for the production of diesel engine fuel for land transportation or commonly called green diesel or renewable diesel. Green diesel or renewable diesel is different from biodiesel or FAME-based biodiesel which is produced by the transesterification process. And green diesel or renewable diesel from HVO also has a number of advantages compared to FAME based biodiesel.

HVO production is also not a new technology. Globally, there are a number of large-capacity commercial HVO plants that use vegetable oil as raw material. The largest plants are Neste in Rotterdam and Singapore with a capacity of 1.28 billion liters per year and Diamond Green Diesel in Louisiana with a capacity of 1.04 billion liters per year. HVO production is closer to petroleum refining technology than conventional diesel production. This is why oil and gas companies may be more interested in developing it than palm oil companies or conventional biodiesel companies. Palm oil mills have raw materials / feedstock, while oil and gas companies may be more relevant to downstream development because of the readiness to adapt technology and develop end products.

HVO is produced by hydrogenation and hydrocracking of vegetable oils and animal fats using hydrogen and catalysts at high temperature and pressure. In this hydrotreating process, oxygen is released from the feedstock consisting of triglycerides and / or fatty acids. This will produce straight chain hydrocarbons (paraffins) with various properties and molecular sizes depending on the characteristics of the raw materials and the operating conditions of the process being carried out. This conversion usually goes through two stages, namely hydrotreatment followed by hydrocracking / isomerization. This hydrotreatment process is usually carried out at a temperature of 300 -390 C and for triglyceride treatment, propane is usually produced as a by-product. The final product of straight chain hydrocarbons can be adjusted according to certain fuel types such as bio jet fuel or SAF. Currently HVO is the third most common biofuel in the world after ethanol and FAME based biodiesel.

PAO is produced as waste or by-product of palm oil mills. PAO will always be produced because palm oil mills cannot have an efficiency level of 100% and the less efficient the palm oil mill, the more oil becomes waste or by-product in the form of PAO. It is estimated that there are currently 1 million tons of PAO in Indonesia and 0.5 million liters in Malaysia or a total of 1.5 million tons. As for UCO or used cooking oil with the use of cooking oil reaching 1.55 million tons/year assuming 10% can be recovered as used cooking oil or UCO, 155 thousand tons/year are produced. In addition to being part of the effort to overcome waste both in palm oil mills and households that pollute the environment, the production of SAF or bio-jet fuel has also contributed to the decarbonization of the air transportation sector. With HVO / HEFA technology that is able to process waste oil such as PAO and UCO, the more PAO and UCO that can be processed, the better.