Oilseed Farming and Biodiesel Plant. Integration Considerations

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1 Oilseed Farming and Biodiesel Plant Integration Considerations Link Shumaker Jeremy Ferrell August 2013 This is an open source document. It was created for the benefit of the contributors, society and the planet s ecosystems; please use it with theses intentions in mind. While it is perfectly legal to distribute this paper freely, please understand that it requires resources to create this type of document and the contributors are open to benefiting from projects that grow out of them. There is plenty of work to be done so please pitch in and share your findings. For further questions, contributions, or collaboration contact: linkshumaker@gmail.com or jcferrell@gmail.com

2 Introduction US and global interest in biofuels has grown in recent years as a means of achieving environmentally sound technology and greater energy security. Because biofuels are made from renewable feedstocks they contribute to a new economy that can exist in perpetuity. Many of these renewable feedstocks can be decentralized and sourced locally therefore they offer a platform for reliable micro-economies to form and prosper. These micro-economies offer the enormous strength of insulation from uncontrollable, volatile macro-economic conditions. While many enterprises contribute to these micro-economies, biofuels promise to play a leading role in their effectiveness and longevity. Biodiesel, a diesel fuel made from animal and plant fats/oils that meets the requirements of ASTM D6751, is a choice biofuel for such micro-economies. Its relative simplicity of production and compatibility with existing infrastructure (petroleum diesel fuel, engines, storage tanks, pipes, etc) present a straightforward path to production, use, and distribution on a local scale (i.e. within 100 miles). Furthermore integration of a biodiesel production facility with a farm and oil crushing facility offers several advantages including: feedstock security for the biodiesel facility, fuel cost security for the farm, reduced transportation costs for the oil, increased value streams for the farm, and shared equipment/utilities. There is also potential to use the biodiesel side-streams as fertilizer, compost additive, weed suppressant, and bioenergy feedstock. The integrated approach leverages flexibility through each step to adapt to market conditions. This paper describes oilseed crop farming, oilseed crushing, and biodiesel production processes as well as synergy considerations for 500 and 2000 acre plots of farmland in central North Carolina. There are three major process steps in this scenario: farming, oilseed crushing, and biodiesel production. This paper describes in general terms the farming, oilseed crushing and biodiesel production steps as well as the benefits of integrating these processes. Figure 1 shows the conceptual material flow chart of a farm to fuel biodiesel production system.

3 Figure 1. Material flow for farm to fuel biodiesel production. The Farming Step For climate zones typical in central North Carolina winter canola has been identified as the oilseed crop of choice. This is due largely to its high oil content ( 40wt% of seed), valuable protein meal, and ability to be substituted for winter wheat which is commonly planted throughout North Carolina in rotation with soybeans or corn. Canola production requires similar equipment used for other grains and row crops for planting, fertilizing, spraying, and harvesting. Canola is small seed with a recommended planting rate at 3-4 pounds/acre so seed drills need to be capable of planting at this rate. Combining canola also presents potential equipment issues due to its small size. Modifying a wheat head combine has been suggested to reduce field loss during harvest. Canola and Rapeseed: Canola and rapeseed are often used interchangeably and often confused. They are both characterized as the species Brassica napus, but have distinct concentrations of erucic acid, differing from the native mustard varieties that average 4.1%. Canola is a trademarked edible variety which signifies Canada Oil Low Acid. It has been

4 selectively bred to produce a fatty acid profile with less than 2% erucic acid and minimal presence of glucosinolate in the oilseed meal. Glucosinolates give mustard family plants/seeds a distinct flavor and can cause dietary problems when fed to livestock. At present, a High Erucic Acid Rapeseed (HEAR) with concentration of 50%, has been developed as an industrial feedstock for bio-based oils, plastics, and lubricants. Planting trials have begun in several regions of North Carolina, supported by a biotechnology consortium. There is significant concern about breeding with and contaminating edible varieties in the field. Crop Rotation: There are several possible rotations to introduce canola into a crop management system. It is generally advised to break up canola plantings 2 or 3 years on the same plot to minimize soil borne pathogens. Conventional crop rotations of soybeans-winter wheat and a two year rotation of soy-wheat-corn-wheat can be modified to include canola. A three-year rotation developed at the Catawba County EcoComplex and Biodiesel Research Facility includes another oilseed crop, sunflower, to maintain overall vegetable oil production while providing three full years between canola plantings. Table 1 summarizes these rotations and their associated oil/meal yield estimates. Trials from this site showed non-gmo canola to be more advantageous for pre-harvest management where a small herbicide application is used to encourage uniform drying before combining. Table 1: Estimated vegetable oil and meal production based on average crop yields by rotation. Rotation Average Vegetable Oil (gal/acre/year) Average Oilseed Meal (lbs/acre/year) 1) Soybeans-Wheat-Soybeans-Canola 85 2,710 2) Corn-Canola-Soy-Wheat 66 1,760 3) Soybeans-Winter Cover Crop- Sunflower-Wheat-Corn-Canola 62 1,488 Canola Pathogen Concerns: Although canola is a highly productive oilseed crop, there are management concerns with widespread planting. Canola is particularly susceptible to two types of pathogens that persist in the soil and reduce crop vitality and yield, white mold and the blackleg. Both are fungal pathogens that develop with high ground moisture and temperatures 70 F, typically during the first phase of the spring canola bloom. These diseases can be controlled with timely applications of fungicide but it is more generally recommended to break up broad leaf crops by rotating the fields with grasses like corn and wheat. Planting canola after corn limits viability of fungal pathogens to persist in the soil and also allows for longer planting windows. Plant breeding programs are actively working on disease resistant varieties. Planning: Planting a minimum acreage of oilseed crops based on the farm s internal diesel fuel needs secures diesel fuel costs for that farm the following year (assuming reasonable seed yield, effective crushing, and proper fuel production). Depending on market conditions the farm can choose to sell the resulting biodiesel or use that amount on farm. Additional acreage planted in oilseed crops results in product that can be sold as seed, oil and meal or processed

5 into biodiesel then sold. The crop residue could potentially be used as a heat source, cellulosic fermentation feedstock, gasification/biochar feedstock, compost feedstock, or left on the field. The Crusher Facility Step After the farm harvests the oilseeds, they are moved to the crusher facility for cleaning, drying, and storage then onto crushing. The crushing step generates a valuable meal stream in addition to the raw oil stream. The meal stream can be sold as is into the feed market while the raw oil is degummed. Depending on market conditions the degummed oil can be sold as it, refined to food quality and sold into the restaurant industry, or sent to the biodiesel facility for processing. Crushing is achieved by two primary means, 1) mechanical extraction and 2) mechanical-chemical extraction using solvents. For farm-scale operations, mechanical extraction is more appropriate and avoids expensive infrastructure and additional chemical handling. Mechanical extruders are generally capable of extracting 75-80% of the available oil in a seed. The remainder, minus a small fraction for moisture loss, is protein meal. Protein meal is a principle ingredient in animal feed rations and has an established commodity value. Meal sales to local feed mills or use on-farm to offset feeding costs are one of the key factors in overall economic viability of oilseed crushing. Vegetable oil that comes directly off the mechanical presses contains impurities that should be removed before processing into biodiesel to increase yield and pass fuel quality specifications. Degumming is the process whereby 1-2% water by volume is added to the raw oil, heated and mixed, then allowed to settle out. The impurities concentrate in the water phase that once removed results in another side-stream. Gums can be added back into the meal, used as a soil amendment, or further processed to make lecithin, a food additive. A complicating and possibly worthwhile option for the crusher facility is to produce food grade oil rather than fuel grade oil. The refining process involves the additional steps of bleaching and deodorizing to produce a light color, neutral, and stable vegetable oil suitable for various applications. Once food quality oil is produced, the crusher facility leases the oil to restaurants (bringing in a significant revenue stream) then picks that used oil back up and takes it to the biodiesel plant for processing. This model (commonly referred to as F3: field, fryer, fuel) adds significant value; however it requires compliance with state and federal food-grade codes and manufacturing practices. During seasons when the farm produces low yields or plants minimal acreage, the crusher facility has the option of buying oilseeds from the market. The biodiesel plant can then use the oil to produce and sell biodiesel fuel into the market (and back to the farm). The Biodiesel Production Step A minimum amount of oil is sent to the biodiesel production facility based on the farm s need

6 for the following year ensuring a farm diesel fuel cost ceiling. Above that, the amount of oil turned into biodiesel is based on market conditions. Biodiesel production consists of reacting the oil into fuel and purifying the fuel. For the case of waste vegetable oil, a pre-step is added preparing the oil for the reaction. There are a myriad of process arrangements within these basic steps and the details of those are beyond the scope of this work. Among many resources on the topic, two are Technical Discussion of Community Scale Biodiesel Production (available from Link Shumaker) and Building a Successful Biodiesel Business (available from Side-streams from the biodiesel process include glycerin bottoms and oily soaps. Each offers further opportunity for value addition and process integration. Glycerin bottoms primarily contains methanol, soap, oily residues (mono-, di-, triglycerides), glycerol, potassium, and moisture. If the methanol is removed, there is potential for the remaining solution to be land applied to build the cropland soil or as a compost additive to accelerate the composting process. Other options after methanol removal include upgrading the glycerin to a higher grade and reacting it into acrolein, acrylic acid, or propylene glycol. The propylene glycol alternative offers the option of using that product for farm equipment and the process chiller. Alternatively, leaving the methanol in allows the solution to be used as a boiler fuel ingredient. The oily soaps can be treated with acid to be made into waste oil burner fuel or sold as a free fatty acid product. There is also potential for using the substance as a degreaser. If biodiesel is used on the farm some lenience can be enjoyed with regard to ASTM specification with little or no difficulty (note that too much lenience in quality will cause failure in the equipment that uses it). However, if fuel will be sold, used on road, or used to generate RINs (EPA Renewable Fuel Standard credits), it must meet ASTM specification. Achieving and verifying ASTM quality fuel requires more planning, process tuning, and testing than simply making a fuel suitable for on-farm use. It is worth noting that offsetting the cost of a biodiesel plant may be achievable by finding and purchasing equipment that has been decommissioned. Bringing It Together Table 2 summarizes the expected amounts of the highest value products (biodiesel and meal) for 500 and 2000 acre cropland scenarios. Co-products (not described in Table 2) that can be used to offset costs or bring in additional value include oil gums, glycerin bottoms, and oily soaps. Furthermore co-locating the operations offers savings by sharing certain equipment and materials. Sharing boiler process heat, cooling fluid from a chiller, compressed air/water/electrical/hvac supply, a forklift, tank farm space (spill containment and storage containers), tools, and filters all offer potential savings by integrating the design of a farm, seed

7 crusher, and biodiesel facility. Table 2. Farm to Fuel Scenarios based on rotation type. 500 Acre Farm Gallons Oil/yr Tons meal/yr Gallons Biodiesel/yr 1) 42, ,645 Soybeans-Wheat-Soybeans-Can ola 2) Corn-Canola-Soy-Wheat 32, ,855 3) Soybeans-Winter Cover Crop-Sunflower-Wheat-Corn-Ca nola 30, , Acre Farm Gallons Oil/yr Tons meal/yr Gallons Biodiesel/yr 1) 169,000 2, ,580 Soybeans-Wheat-Soybeans-Can ola 2) Corn-Canola-Soy-Wheat 131,000 1, ,420 3) Soybeans-Winter Cover Crop-Sunflower-Wheat-Corn-Ca nola 123,333 1, ,133 Next steps in developing this scenario include cost analyses of each step in the process, a more detailed study of how to recover the most value for co-product streams, further research on breed contamination between Canola and HEAR mustard crops, and more thorough mass/energy balances of sample scenarios for each process step based on real world data.