We are nearing the end of our journey, as there is only one more blog after this one. If you would like to look back and see all of the feedstocks we have covered start here with our first post.  In this post we explore the feedstocks Sunflower Oil and Tung Oil as we continue our look into different types of feedstock that Renewable Energy Group (REG) studied in 2009 in the Feedstock and Biodiesel Characteristics Report.

Sunflower Oil

The Sunflower oil in this project was purchased from Jedwards, International, Inc.  The common sunflower scientific name is Helianthus annuus.

First domesticated in the Americas the plant was exported to Europe in the 16^th century and has become a staple as a cooking ingredient.  According Wildflower.org the common sunflower prefers full sun and well-drained soil. The plant grows up to 8 feet tall and has coarse hairy stems and leaves. The flowers are bright yellow surrounding a central maroon disk, that as it matures, holds the seeds and produces the oil.

The most known uses for sunflower seeds and its oils include; foods, cooking oils and butters. The pressed seed oil is useful for food and the resulting cake (matter left after the oil is harvested) is commonly used as animal food. One of the more interesting uses for the plant is, that it can produce a natural latex in its leaves. This latex can be used to produce hypoallergenic gloves.  The purpose of this post though is to discuss the possibility of biofuel created from sunflower seeds. Biodiesel magazine talks about both the pros and cons for this plant as a feedstock option:

“Because sunflower oil is priced higher than soybean and canola oils, its use as a feedstock for commercial biodiesel refining may be hindered in the U.S. market, according to the National Sunflower Association (NSA). However, there is an interest in the tall golden flowers because the seeds yield about 600 pounds of oil per acre, considerably more than soybeans, which produce a little over 500 pounds per acre.”

Because of the high value of the oil in other areas, using the oil for biodiesel can be cost prohibitive.  Higher concentrates of oil per acre can be vital as more efficiency in  biofuel production becomes necessary. According to Farm Energy, 15,000 to 25,000 plants per acre can be grown.  This means that a small or large farm can use this crop profitably or simply in the production of fuel for that farm.

Tung Oil

The Tung oil from this study was purchased from Sigma-Aldrich Co. The Tung tree, Vernicia fordii, is native to China and Vietnam.  This tree can be over 60 feet in height and is deciduous. According to Texas Invasive Species Institute:

“The bark is smooth, thin, and exudes white sap when cut. The leaves are simple, heart-shaped or with three lobes, and 6-10 inches long. The white flowers have 5 petals with red veins, and they bloom before the leaves emerge. The toxic fruits can grow up to 3 inches in diameter and are reddish green when fully developed.”

This tree is valued for its oil from the seeds.  Traditionally this oil was used in lamps and even as waterproofing on boats.  In more contemporary time this oil is used in varnishes and paint.  This value encouraged the importation of this tree. According to Texas Invasive Species Institute there was over 10,000 acres planted in the United States in 1927.  Cultivation of this tree has waned in the US after frosts and hurricanes destroyed many of the plantations.

This is one feedstock that isn’t part of the food vs fuel controversy.  The Tung tree and its oil is poisons to humans.  Even one seed from the fruit can be fatal, with symptoms including slowed breathing, vomiting and diarrhea.

Last article for biodiesel feedstocks was – Soybean Oil & Stillingia Oil

If you would like to learn more about bio-diesel you can check out this post Every Question We Have Been Asked About Biodiesel

This post covers one of the most common Feedstocks in the US, Soybean Oil. In addition, we are also looking into Stillingia Oil in our deeper dive into the feedstocks that Renewable Energy Group (REG) studied in 2009 in the Feedstock and Biodiesel Characteristics Report. If you would like to learn more you can follow the link to read more here about the feedstocks we have examined in the past.

Soybean Oil

Soybean (Glycine max) is a legume that originated in East Asia.  This plant has had a long history of cultivation. Many botanists believe that this bean was first domesticated as early as 7000 BCE in China.  It grows well in warm, well-drained sandy soil.  According to Encyclopedia Britannica,

“The soybean is an erect branching plant and can reach more than 2 metres (6.5 feet) in height. The self-fertilizing flowers are white or a shade of purple. Seeds can be yellow, green, brown, black, or bicoloured, though most commercial varieties have brown or tan seeds, with one to four seeds per pod.”

The United States has had soybeans as part of its history as far back as 1765.  In the 1950’s the US became the world’s largest exporter of soybeans.  If you would like to learn a little bit more about how this crop became important to the US check out this link.

This edible bean has a lot of uses.  A bean is made up of about 20% oil and 80% meal. According to NC Soybean Producers Association,  most soybeans are processed for the oil.  After the oil is removed, 3% is used directly in food products with the rest of the meal used for animal feed.

The United Soybean Board breaks down which animals are using soybeans as the protein source.

“The soybean meal fed in the U.S. goes to several segments of animal agriculture.

• Poultry eats about 67 percent.

• Pigs consume nearly 21 percent.

• Beef and dairy cattle use just over 10 percent.

• The rest goes to aquatic farming like fish and shrimp, other farm animals and companion animals like horses and pets.”

The oil is then used as food (68%) such as cooking oil – most cooking oils in the US that are listed as vegetable oil is soybean oil.   This oil can be turned into biofuel later.

The rest of the oil is used to create biodiesel and other products such as candles, paints and even plastics.   This crop is important to much of the farming community in United States. If  you would like to learn more there is a plethora of information about this subject on the internet.

Stillingia Oil

The Stillingia Oil from this study comes from the Chinese tallow tree (Triadica sebifera).  Common names for this plant include; Florida aspen, grey popcorn tree, candleberry tree or chicken tree. A native plant to Eastern China and Taiwan, while it can be an invasive species in the US.  This video from UF / IFAS Center for Aquatic and Invasive Plants  talks a little bit about how the plant looks and some of the characteristic of it.

This tree has spectacular fall colors and it loves warm, and moist climates. The tree grows up to 30 to 40  feet and loses its leaves in the winter (deciduous).

There are several uses for this tree, include soap made from the seed’s aril (the extra seed covering that are white and waxy in this plant).   Use as a nectar plant for honeybees. (source) In areas with seasons it is ornamental and displays beautiful colors along with being a great shade tree in the summer.

Finally, there is a large potential for biodiesel from the seed Oil. Biodiesel magazine talks about some of the potentials for this feedstock:

As a biodiesel feedstock, both the outer coating and the kernel of the tallow tree seeds are high in oil content, as the seeds contain 45 percent to 60 percent oil. Commercial plantations in other countries typically contain about 160 trees per acre, which are trimmed low for hand harvesting. Yields average 12,500 pounds of seed per acre, which can produce 2,300 pounds of stillingia oil, 2,500 pounds of vegetable tallow, 1,400 pounds of meal and nearly 5,000 pounds of biomass waste. In China, the meal is used as a high-nitrogen fertilizer. Breitenbeck says commercially produced trees average 645 gallons of oil per acre and some experts cite yields as high as 970 gallons per acre.

Since this is an invasive species in the US the benefits and the issues will need to be compared.

Last article for biodiesel feedstocks was – Poultry Fat & Rice Bran Oil

Looking further into biodiesel feedstock we continue with Poultry Fat and Rice Bran Oil in our deeper dive into the feedstocks that Renewable Energy Group (REG) studied in 2009 in the Feedstock and Biodiesel Characteristics Report. If you would like to see more you can  read more here about the feedstocks we have examined in the past.

Poultry Fat

Rendering is the process of turning the left over animal products into fat or tallow. After the common parts of the animal are harvested the remaining parts are ground up and cooked. The oil and fat is then separated from the protein solids. Poultry fat, commonly made from chicken, is different from other forms of fat and tallow.  It tends to have less saturated fat. According to Farm Energy:

“Beef tallow and pork lard are typically about 40% saturated (sum of myristic, palmitic and stearic acids). Chicken fat is lower at about 30-33%. For comparison, soybean oil is about 14% saturated and canola oil is only 6%. Thus, tallow and lard are usually solid at room temperature and chicken fat, while usually still liquid, is very viscous and nearly solid.”

The high content of saturated fat can be a draw back for biodiesel produced from animal products. Beef Tallow in this study produced B100 (100% biodiesel) with a cloud point of 16° C or 60.8° F.  The Poultry Fat B100 in this study had a cloud point of 6.1° C or 42.98° F, in comparison Soybean Oil B100 in the same study was 0.9° C or 33.62° F.

One of the benefits of using animal fats for biodiesel is a higher Cetane number. (Source) “cetane number is a measurement of the quality or performance of diesel fuel. The higher the number, the better the fuel burns within the engine of a vehicle.”  Petroleum based fuels have a cetane number between 40 -44, soybean based biodiesel is between 48 – 52 and animal fat based biodiesel can have values over 60. (Source)

Rice Bran Oil

Rice bran oil is a vegetable oil which is greatly available in East Asia countries. It is a byproduct of rice processing, containing about 15-23% oil.  The Rice Bran Oil that was used in this study was refined, bleached, deodorized, winterized (RBDW).

Rice bran oil is similar in make up to peanut oil made up of monounsaturated, polyunsaturated, and saturated fatty acids.

While the Oil is this study was considered non-edible, when processed in other ways the oil can be used in cooking and is popular for Asian countries such as Bangladesh, China, India and Japan.

Last article for biodiesel feedstocks was – Palm Oil & Perilla Seed Oil