The Huge Unexploited Potential of Generating Biofuels from a Food Processing Residue, Palm Kernel Oil (PKO), with Ghana in Perspective

July 20, 2016

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By Theophilus Kumah* (Advanced Biofuels USA) Energy is a great determinant in ensuring the growth of the economy of every country. Ghana, as a country, has faced some instability in the supply of energy for domestic and industrial use owing to the fact that it has over-relied on hydrothermal power as its main source of energy. It therefore doesn’t come as a surprise that some other sources of energy are currently being considered. Nuclear energy, solar energy, wind energy, thermal energy and most recently bioenergy, including bio-based energy for heat, power, light, cooking fuel and transportation.

Background

Interest in generating first generation biofuels has rather been low, likely because of the issue of food security. Thus, the main source for bioenergy currently being considered in Ghana is Municipal Solid Waste (MSW) which is a second generation feedstock.

Agricutural residues and wastes may also provide valuable second generation feedstocks. With oil palm being the fifth-largest crop in Ghana in terms of area planted, the possibility of generating transportation fuel from the palm kernel residue from palm oil production could further increase the value of the crop to the nation[1].

Global production of palm oil was about 48.55 million metric tons in 2011, with African countries producing about 5.4 percent of the global production total[2]. In 2011, Ghana produced 120,000 tons of palm oil, making it the 17th largest producer in the world. Ghana exported 1,713 tons of palm oil with a total value of $ 617,000 (USD).

Palm kernel oil and palm oil are two of the few highly saturated vegetable fats; these oils give the name to the 16-carbon saturated fatty acid palmitic acid that they contain[3]. They both come from palm trees, but there the similarity ends. Palm oil comes from the palm fruit, while palm kernel oil is extracted from the palm kernel nut. After the processing of the fresh fruit bunch to yield palm oil, the product that is left is the shelled palm nut which can be cracked to yield the palm kernel nut and the shell. While the shells can be used as fuels and for road construction, though the market is not well developed in this country, the palm kernel nut can be crushed and processed to yield palm kernel oil and cake.

And, while over 80 percent of the fat in palm kernel oil is saturated, only 50 percent of the fat in palm oil is, making palm oil easier on arteries.[4]

Palm Kernel Oil

Palm kernel oil, like other vegetable oils, can be used to create biodiesel for internal combustion engines, specifically compression ignition engines. Biodiesel has been promoted as a renewable energy source to reduce net emissions of carbon dioxide into the atmosphere. Therefore, biodiesel is seen as a way to decrease the impact of the greenhouse effect and as a way of diversifying energy supplies to assist national energy security plans.

Local Africans use palm kernel oil to fuel native lamps for lighting in rural communities that are not connected to electricity. Palm kernel oil can also be directly combined with petro diesel or used in making biodiesel for diesel engines.

Palm kernel oil is also used to make biodiesel by processing through transesterification to create a palm kernel oil methyl ester blend, which meets the international EN 14214 specification, with glycerin as a byproduct. The actual process used to make biodiesel around the world varies between countries, and the requirements of different markets.

Palm kernel oil is more saturated and so can be hydrogenated to make a wide range of products for food industries. Palm kernel oil in its hydrogenated and fractionated form is widely used either alone or in blends with other oils for the manufacture of cocoa butter substances and other confectionary fats.

On 16 December 2007, Malaysia opened its first biodiesel plant in the state of Pahang, which has an annual capacity of 100,000 tonnes, and also produces byproducts in the form of 4,000 tonnes of palm fatty acid distillate and 12,000 tonnes of pharmaceutical grade glycerine.[5] Neste Oil of Finland plans to produce 800,000 tonnes of renewable diesel per year from Malaysian palm oil in a new Singapore refinery from 2010, which will make it the largest biofuel plant in the world, and 170,000 tpa from its first second-generation plant in Finland from 2007-8, which can refine fuel from a variety of sources. Neste and the Finnish government are using this paraffinic fuel in some public buses in the Helsinki area. Interestingly, some US cities are starting to require renewable diesel for all their diesel-powered vehicles and machinery.

Processing of Palm Kernel Oil, Palm Kernel Shell and Palm Kernel Expeller

According to Anaekwe, 2011[6], it is generally believed that no part of the oil palm tree is useless. For each hectare of oil palm, harvested year-round, the annual production averages 10 tonnes of fruits, yielding 3,000 kg of pericarp oil and 750 kg of seed kernels yielding 250 kg of high quality palm kernel oil as well as 500 kg of palm kernel meal.

At present, there are three major types of extraction methods used in the extraction of palm kernel oil from palm kernels. These methods are: Traditional extraction method, direct solvent extraction, Mechanical extraction using high pressure screw pressing.

The extraction of the palm kernel oil in Ghana has been low as most of the attention is given to the palm oil.

Palm kernel shell (PKS) is actually the by-product from the palm oil industry. Before the era of palm kernel shell being used for bioenergy, the oil palm owner would bury the palm kernel shell and let it become black colour compost. This is sort of organic fertilizer but because of the hard shell, it takes much longer for it to convert to useable organic fertilizer. There is a suggestion that these shells can be used for fertilizer. However, it is important to note that more study on this topic could provide information on characteristics of this potential fertilizer and potential markets.

Aside from the palm kernel oil which is extracted from the kernel nuts directly, the residue from the extraction results in both a high quality oil, palmolein, and Palm Kernel Expeller (PKE) which has also gone under some experiments to explore its viability as a biofuel feedstock.

The inner palm kernel is where these products come from. The inner nut, the kernel, is sent to the expeller factories where it is expelled twice to produce higher quality oil, palmolein, which is used for cooking (especially frying) as well as production of baby oils in the cosmetic industry and PKE. To accomplish this, the kernels are centrifugally cracked in a drum machine and milled. The residue left after palmolein extraction from palm kernels is Palm Kernel Expeller (PKE). Palm Kernel Expeller is a good animal feed.

PKE can also be used as a biofuel feedstock.

According to the results of an experiment, PKE is a good biomass feedstock: ash is rather low, it does not have strong smell, and net calorific value is rather high. Moisture content of the PKE is on the level of 9-10%, Ash content is 3.7-4%. Chlorine is 0.15%, Sulphur 0.28% and Net calorific value is 16, 8-17 GJ per mt.[7] This indicates that PKE poses a huge potential in its exploitation as an alternative raw material for biofuel derived from the oil palm.

Palm Kernel Shell (PKS) Pellets

Biomass pellets are a popular type of biomass fuel, generally made from wood wastes, agricultural biomass, commercial grasses and forestry residues. In addition to savings in transportation and storage, pelletization of biomass facilitates easy and cost effective handling. Palm kernel shells are a fibrous material with a relative small size. Because of the residue palm oil, the heating value of palm kernel shells is slightly higher than the lignocellulosic biomass.[8] The palm kernel shell is widely used in Malaysia, Indonesia, Thailand, Japan, Korea and some Europe countries.

Some Remarkable Advantages of the PKS Pellets are:

PKS pellets have low moisture content
PKS pellets are high in heating energy and efficiency
PKSl pellets are easy to handle and store
PKS pellets are easy to control and have a broad application
PKS pellets are suitable for most boiler grating systems
PKS pellets generate low to no smoke during the combustion[9]

Conclusion

With the increasing demand for energy in Ghana, if careful consideration is given to biofuels and more specifically to expanding use of the multiple biofuel and bioenergy products derived from residues from palm oil production, the nation could rest assured of accessing an alternative source of energy which is also environmentally friendly. That would also relieve the over dependence on the hydro-electric power generated at Akosombo to cater for the whole nation. READ MORE

[1]Oil Palm – Ghana’s next ‘Goldmine’, http://footprint2africa.com/oil-palm-ghanas-next-goldmine

[2] FAOSTAT, http://faostat.fao.org

[3] Palm kernel oil, https://en.wikipedia.org/wiki/Palm_kernel_oil

[4] http://www.eatingwell.com/nutrition_health/nutrition_news_information/palm_oil_vs_palm_kernel_oil

[5]Prospect of Biodiesel Production from waste oil and fat in Malysia

http://ir.unimas.my/4590/1/Prospect%20of%20Biodiesel%20Production%20from%20Waste%20Oil%20and%20Fat%20in%20Malaysia%20(24pgs).pdf

[6] Anaekwe E. N. 2011. Business Development Consultant

http://farriconsultingng.blogspot.com/2010/04/buying-and-sellingof- palm-kernel-nuts.html.

[7] Palm Kernel Expeller, http://www.renergyuk.com/palm-kernel-expeller/

[8] Palm Kernel Shells as Biomass Resource, http://www.bioenergyconsult.com/palm-kernel-shells-as-biomass-resource/

[9]http://www.biopelletmachine.com/biopellets-making-guidance/PKS-pellets-making.html

*Theophilus Kumah brings his chemical engineering degree from Ghana's Kwame Nkrumah University of Science and Technology and his interest in innovations for biofuels in Ghana to serve as a researcher and writer for Advanced Biofuels USA.