Biodiesel: Recent Developments

Biodiesel has developed into an established biofuel during the past more than two decades. However, the production capacities, end-uses, as well as technologies are still evolving further. The present article presents a snapshot of recent market and technological developments related to biodiesel, its raw materials and technologies.

USA – PRODUCTION CAPACITY

As of 1 January 2022, there were 72 biodiesel production plants in the USA, with a combined capacity of 2.255 billion gallons per year. As of 8 August 2022, the capacity fell by three plants, amounting to 154 MMgy (million gallons per year).

Bulk of the biodiesel capacity in the USA is located in the Petroleum Administration for Defense District (PADD) 2, which includes the Midwest region of the country. This PADD 2 region currently has 37 biodiesel plants with a combined production capacity of 1.444 billion gallons per year. The number of production plants remained steady as compared to 2021, but the capacity fell by 39 MMgy. Another important region, PADD 3, located along the Gulf Coast of USA, currently has 12 biodiesel plants with a combined capacity of 455 MMgy, compared to 15 plants with a combined capacity of 580 MMgy that were in place during 2021. The PADD 5 region, which covers the West Coast of the country, Alaska and Hawaii, lost one biodiesel plant between 2021 and 2022. Their total nameplate capacity increased in the same period. As of August 2022, there are nine biodiesel production facilities with a combined capacity of 199 MMgy, compared to just ten facilities with a combined capacity of 194 MMgy, during 2021. Another region, PADD 1, which includes the East Coast of the country, registered an increase in the number of biodiesel plants from 13 in 2021 to 14 this year (2022). The combined biodiesel production capacity of the region also increased to 157 MMgy, from 152 MMgy in 2021. There is no biodiesel production plants located in the PADD 4 region, which covers the Rocky Mountains.

The US production capacity of renewable diesel, a major variant of biodiesel consuming vegetable oils and fats as raw materials, and associated fuels, more than doubled between 2021 and 2022, according to the US Energy Information Administration (US EIA), as per the data released on 8 August 2022. The USA has 11 biorefineries that produce renewable diesel and other associated biofuels, including renewable heating oil, renewable jet fuel, renewable naphtha and renewable gasoline. The combined nameplate capacity of renewable diesel is 1.75 billion gallons per year. This is significantly higher than the combined capacity of 791 MMgy of six facilities as of 1 January 2021. Most of the renewable diesel production capacity is located in the Petroleum Administration for Defense District (PADD) 3, a region located along the Gulf Coast of the country. There are two production facilities in the region, which had a combined renewable diesel capacity of 437 MMgy as of 1 January 2021. This capacity increased to 1.082 billion gallons per year as on 1 January 2022.

BIODIESEL RAW MATERIALS / FEEDSTOCK

Soybean Oil

As of 12 August 2022, the United States Department of Agriculture (USDA) reduced its estimate for 2021-22 soybean oil use in biofuels (including biodiesel) by 200 million pounds in its latest World Agricultural Supply and Demand Estimates (WASDE) Report, as compared to its previous month’s report. The forecast for the year 2022-23 soybean oil use in biofuels has been maintained.

The USDA has predicted that 12 billion pounds of soybean oil will be consumed to produce biofuels during the year 2022-23, a forecast maintained from the July WASDE Report. However, the agency now estimates that 10.5 billion pounds of soybean oil will be consumed for biofuels production during the current year 2021-22, down by 200 million pounds, when compared to the 10.7 billion pounds forecast made in July 2022. During the year 2020-21, approximately 8.85 billion pounds of soybean oil were consumed for biofuels production.

Based on the US EIA data for 2020, the soybean oil consumption represented over 60% of the biodiesel feedstock. There is increasing concern that the land where higher carbon capture crops are currently grown will be turned over to soybean cultivation to meet the escalating oil demand for biodiesel production.

Non-Edible Oilseeds

Biofuels, including several variants of biodiesel consuming vegetable oils and fats as feedstock, are becoming the mainstay throughout the world. The availability of used cooking oils and tallow (animal fat) are limited. Thus, the increasing production and consumption of biodiesel and its variants are expected to put pressure on the global supply of oils and fats, creating competition between the biodiesel manufacturers and food applications. This is already happening in the USA. With increases in biodiesel production as mandated by the State of California and the US Government, food manufacturers have indicated that they cannot by soybean and other vegetable oils because the supplies have gone to produce transportation fuels like biodiesel. They testified to the US Congress that soybean oil prices have more than quadrupled in the last quarter of 2021 due to the increased demand by biofuel refineries.

This has led researchers to increase their efforts to develop various non-edible oilseeds for the production of biodiesel.

The United States Department of Agricultural (USDA) has supported research projects across the country for more than a decade, to identify and develop high yield oilseed crops that could be used to make biodiesel and other biofuels. Investments in these projects are now nearly ready to pay off. As the industrial oilseed crops like pennycress, camelina and carinata are non-edible, their use as feedstock in the production of biofuels will not affect food manufacturers’ bottom line. Also, these crops are planted in the off-season when fields are typically idle.

Carinata, i.e., Brassica carinata, a traditionally bred mustard seed variety, has been developed under one of these research projects. Carinata, with about 40% oil content, is on par with soybean. Also, its meal has 35 to 40% protein, which can be used for animal feed. This non-edible oilseed and also other oilseeds, are in the process of undergoing US EPA certification in preparation for making it eligible for sale in California. The popularity of the carinata oilseed crop is growing among the Canadian seed developers. One producer company’s sales tripled due to increased sales of camelina oil in the year 2020. Carinata is also taking hold in South America. An Australian agrochemical company sold carinata seeds (brand named Nuseed) to farmers in Argentina for commercial use. All the oil produced from this cultivated Nuseed has been sold to Saipol, a biodiesel producer in Grand-Couronne, France. Similarly, other non-edible oilseeds are also on the path of commercialization in the near future.

Epigenetics

The science of heredity in which the molecular environment around a gene is passed down to the offspring as the cells multiply through mitosis of meiosis, is called as epigenetics. This science is being harnessed to develop custom varieties of non-edible oilseeds. Plant epigenetics is altered to develop specific heritable traits. Several crop enhancement companies are developing various oilseeds using the epigenetics. These techniques are about ten times faster than those of gene editing. Epigenetics is being used to identify and optimize traits that make plants more resilient with respect to climate change, diseases and reduced chemical use. Other traits that optimize nutrition, appearance and flavor are also under investigation. Plant breeders can progress from concept to a plantlet with a new trait in 15 days using epigenetic techniques, compared to 150 days needed for gene editing. A combination of epigenetics, genomics and other tools with high throughput analytics and artificial intelligence allows more data to be gathered and evaluated faster, resulting in even faster development. Although the concept of epigenetic breeding is still unproven in some crops, it will play an important role in developing many useful non-edible oilseed varieties in future. These may improve the supply of oils feedstock for the production of biodiesel.

COMPETING TECHNOLOGY – HYDRODYNAMIC CAVITATION

At present most of the biodiesel plants use traditional reactors for the main interesterification (or transesterification) reaction to produce mixtures of methyl esters of fatty acids from oils and fats. These reactors use conventional mechanical stirring.

A not-so-new technology known as Hydrodynamic Cavitation’ has started making inroads to the traditional technology and equipment used in the production of biodiesel. Although the technique has been commercialized for several different chemical processes, the number of industrial biodiesel plants utilizing this hydrodynamic cavitation process is still minimal. However, several companies have started offering hydrodynamic cavitation equipment of different capacities for the manufacture of biodiesel. Results obtained from operating two biodiesel plants producing 100 tonnes per day of biodiesel have shown that the total capital investment and total product cost hydrodynamic cavitation are roughly 65% and 10% lower than those for mechanical stirring process, respectively. It has also been reported that hydrodynamic cavitation could significantly reduce materials and energy consumption, owing to higher reactor yield and lower alcohol and catalyst consumption.

Mechanical stirring does not provide enough mixing of the oil and alcohol during interesterification, and also has longer reaction times, high energy consumption, high alcohol-to-oil ration and high catalysts consumption. Additionally, batch reactors are still used to produce biodiesel, which require significant space and high capital and operating costs.

The hydrodynamic cavitation process is used to enhance the contact surface area between oil and alcohol, thus, resulting in more efficient mixing. Hydrodynamic cavitation can be produced using either rotational equipment or constriction device. The constriction-based equipment is a more common for biodiesel manufacture. It mainly consists of a pump and a constriction device, such as a venture or orifice, situated downstream of the pump’s outlet. The reaction mixture of oil and alcohol with the catalyst is pumped through the constriction at high flow rate. This operation results in formation of tiny emulsions and a considerable increase in the contact surface area, and, better mixing in turn. The constriction-based hydrodynamic cavitation reactors are simple in terms of design, structure and operation and easy to scale-up for industrial applications.

The other hydrodynamic cavitation equipment is of rotational type, also called as high-speed homogenizer, in which the reactants flow through a narrow space between two concentric tubes. The outer tube is often fixed and the inner tube rotates very rapidly. Tiny emulsions are produced resulting in enhanced contact surface area.

Hydrodynamic cavitation is proposed to be simple, efficient, time-saving, ecofriendly and effective technology for cleaner production of biodiesel. However, its spread is limited till date due to lack of information and limited number of plants. Hydrodynamic cavitation process also suitable for continuous production of biodiesel.

This technology is likely to compete with the currently used traditional interesterification equipment and processes in future, especially due to its competitiveness on several parameters.

PATENTS

Searching the term ‘BIODIESEL’ in various patents databases offers the following results – the number of patents related to biodiesel.

Google Patents – 192434 patents across several countries

US Patents (1976 to present) – 10186 patents

European Patents (Espacenet) – 34489 patents

Thus, a huge number of patents related to biodiesel have been issued in various countries and regions, and the number is still growing.

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