Use of Existing Fuel Products Pipelines for Biofuels
Shipments Ethanol cannot easily be shipped via fuel products pipeline because it is a good solvent and would remove sulfur and other impurities from the pipeline system, resulting in contamination of the shipped ethanol.
Biodiesel is also a good solvent and could remove sulfur and other impurities from the pipeline system, resulting in contamination of the shipped biodiesel. In addition, there is concern regarding traces of biodiesel left over in the pipeline system. There is a possibility that trace methyl ester (biodiesel) could disarm the coalescers in aircraft fuel and potentially compromise the safety of the aircraft. There is thus a proposal to limit the methyl ester content in the pipeline system in the USA to 5 PPM as a result of this concern.
A national ethanol pipeline?
Obstacles to Ethanol Pipeline Shipments There are 2 types of challenges involved in moving ethanol through a pipeline:
1. Challenges due to the corrosive nature of ethanol.
2. Challenges due to incompatibility with other products and substances within the pipeline.
The obvious challenge is that ethanol behaves so much differently than the refined petroleum products that are typically moved through pipelines. More work is needed to find ways to overcome ethanol’s effects on the pipe, the valves and the pipeline systems themselves.
A key consideration is whether a new dedicated pipeline should be built, and if built, where it should be located. The other key question is whether long-term prices and demand would be able to support the building of a vast trans-national pipeline. In the United States , even the Renewable Fuels Association (RFA) has stated that it is not certain that a dedicated ethanol pipeline would provide the same transport security as the more traditional barges, rail cars, and trucks.
Ethanol Solvency Issues: Ethanol’s solvent properties pose additional challenges. Over years of use, small quantities of residual sulfur and dirt from petroleum products can build up in existing pipeline systems. Although these are not soluble in petroleum products, they can be in ethanol, which can lead to discoloration and product contamination. Ethanol (and biodiesel) can strip lacque rs and deposits from internal pipeline surfaces and carry them as impurities. A dedicated ethanol pipeline would not encounter these issues, because these contaminants/deposits only arise from prior transport of petroleum products.
Materials Compatibility: Compatibility and corrosion issues can arise because of the way ethanol reacts with some materials in the pipeline and associated equipment. Ethanol and biodiesel can also degrade materials used in gaskets, o-rings, and seals used in fuels transportatio n and storage systems. Elastomers can experience swelling, shrinking and cracking when exposed to ethanol or biodiesel . Polymers used for coatings may be degraded by certain b iofuels as well.Corrosion of certain non-ferrous metals used in gauges, meters, valves, and pumps may occur . Any part of the supply system that will be converted to biofuels service needs to be assessed for materials compatibility and refitted with more resistant materials where required.
Stress Corrosion Cracking: Another challenge experienced in ethanol transportation by pipeline is Stress Corrosion Cracking (SCC) associated with ethanol movement and storage in pipelines and storage tanks. Stress corrosion cracking (SCC) can be defined as the slow growth of cracks along the inside of the pipeline, which are caused by mechanical stress and exposure to a corrosive environment. Research, largely funded by pipeline companies, has made great strides in addressing this problem. Industry/government research by Pipeline Research Council In ternational, Inc. (PRCI) 8 has found that ethanol-gasoline blends containing up to 15 percent ethanol by volume (E-15 and below) can be transported in existing pipelines without any design or operational modifications. PRCI also found that higher ethanol-containing blends (E-20 and above) and fuel-grade ethanol can be transported without SCC when certain commercial inhibitors are added. The efficacy of commercial inhibitors to mitigate SCC must be assessed prior to their use.
Water and Biofuels Fuel Quality: Small amounts of water enter pipeline systems from petroleum fuels, terminals and tank roofs. This is generally not a problem during pipeline transportation of refined petroleum products, because the water can separate in a tank and can be drained off. Unlike petroleum products, ethanol has an affinity for water as it flows through the pipeline network. The water-ethanol mixture has the potential to separate from petroleum products with which it may be mixed, resulting in degraded fuel quality. This can be managed by taking steps to cover tanks and remove excess water at certain points in the supply and distribution system.
Typical Biofuel Transport Modes
Biodiesel and biodiesel blends are transported primarily by dedicated (or washed) tanker trucks and rail cars. I f the truck or railcar was used for diesel shipment in the previous load, no washing is needed, but if another type of petroleum fuel was shipped, the tank must be washed.
Ethanol and ethanol blends are also transported mainly by dedicated (or washed) tanker trucks and rail cars. If the truck or railcar was used for gasoline shipment in a prior load, no washing is needed, but if another type of petroleum fuel was shipped, the tank has to be washed.
Ethanol and ethanol blends are generally not transported via pipeline due to some concerns regarding corrosion and contamination.
Primary terminals (also called “product terminals”) are generally located near major markets and transportation modes. Some terminals are located at refineries, while others are separate tank farms that receive fuel products by pipeline, tanker truck, rail car or marine tanker. Primary termin als are equipped with product delivery and loading racks that vary from one terminal to another. For example, some terminals linked via pipeline will not necessarily have racks that are adapted for other modes of transportation (train or truck). In region s with ample waterways, petroleum products may be transported to primary terminals by marine tankers. In regions that are essentially land-locked, products are often transported from refineries to terminals by pipeline. For marine shipments of biofuels, there may be additional storage infrastructure required at the marine terminal. From the marine terminal, the biofuel would be delivered by truck or rail, unless a dedicated biofuels pipeline could be justified. Since primary terminals are designed to provide downstream distribution of finished products, they all have tanker trucks and high-performance fuel injection equipment at the loading rack to prepare fuel blends (i.e., in-line blending).
Pipelines are a key part of the petroleum fuel transportation infrastructure. The petroleum fuels are transported via pipeline to primary or secondary terminals, which then serve as distribution points to nearby retail sites that are supplied by tanker trucks. It is typically at these terminals that biofuels are blended with petroleum fuel for distribution. At present, biofuels are usually transported to the blending terminals by truck, since there are no dedicated biofuel pipelines and the terminals are not generally linked to the railway network.
Rail Cars: Biodiesel (B100) or ethanol (E100) could move by rail from the biofuel production plant to destination terminals (mainly primary terminals or, in some cases, secondary terminals equipped with rail spurs). Rail shipment is generally the most cost-effective delivery method for medium-range and longer-range destinations (i.e., 500 to 5,000 km) that are incapable of receiving product by barge, tanker or pipeline. Rail line coverage and access va ry from region to region. Some te rminals lack rail receipt capability, requiring biodiesel (B100) and ethanol (E100) to be transported by truck. Rail delivery might also prove infeasible in colder climates, unless the rail cars are heated and a heating system is in place at the destination terminal.
Because of the number of railcar units, the smaller volume of biofuel shipped per unit , and the laborious process of cargo unloading and inspection, rail shipments require more effort compared with ocean tankers, for example. The transportation of biodiesel and ethanol via train also requires more complex logistics (availability of heated or dedicated rail cars, delays due to cleaning rail cars in the case of non-dedicated rail cars or heating rail cars at the terminal, etc.). In some cases, installing heating systems or rail spurs adds to the terminal adaptation costs.
Tanker Trucks: In many cases, a tanker truck delivers B100 or E100 directly from the production plant to nearby terminals. In distant markets, tanker trucks may also pick up biofuel blends at primary terminals (that have received biodiesel or ethanol by tanker or rail), for delivery to secondary terminals that either cannot take product other than by truck or that have insufficient tankage for larger quantity deliveries. The redistribution of bi ofuel blends to retail outlets and end-users is also made by trucks.
Typical Blending and Distribution Practices
Ethanol is usually “splash blended into tanker trucks or rail cars that already contain gasoline. The ethanol blended with the gasoline mixes readily and does not stratify.
Biodiesel is also generally splash blended or blended in tanks near the point of use. In the European Union (EU), blending is primarily done “in line” at refineries. The “splash blending” of biodiesel may result in some shock crystallization,depending on the temperature during blending or the means by which the splash blend is administered. In-line blending provides contact between the diesel and the biodiesel and mitigates this risk. At primary terminals for ethanol blending, E100 is injection or splash blended into trucks (or rail cars) before being taken to secondary terminals or to retail. Similarly, at primary terminals for biodiesel blending, the B100 is blended with the diesel by injection (or in some 14 cases splash blending) before being distributed in its blended form B5-B20) to secondary terminals or retail outlets (service stations, card locks, users with their own storage facilities). At this stage, the modes of shipment used no longer have to be insulated and heated.
Existing petroleum distribution terminals usually do not have rail access, creating a distribution infrastructure challenge for biofuels. Petroleum distribution facil ities were generally designed for pipeline distribution of petroleum fuel products. In r emote or smaller petroleum distribution terminals, product receipts were designed around truck receipt and delivery. In most cases, therefore, distribution of E100 or B 100 or blended biofuel product by rail is usually impractical.
From secondary terminals (or depots), blended biofuel product is moved mainly by tanker truck to retail outlets fueling stations–petrol and gasoline stations with direct delivery to end-users. Delivery distance, costs and carbon footprint of distribution may be greater for biofuel blends than for purely petroleum-based fuels due tho the concentration of biofuel feedstocks and refineries in agricultural regions which are remote from m any key urban population centers.
The cost of shipping feedstock s greater than 100 miles is generally prohibitive. In the case of adv anced biofuel feedstocks such as biomass for cellulosic ethanol, even with densification technologies, the transportation costs become prohibitive beyond 100 miles. Thus, the location of future cellulosic ethanol plants is likely to be dictated by proximity to feedstock as opposed to proximity to market, similar to the current situation with first generation biofuels. This also implies that most feedstocks will be delivered by truck, and that most biofuel production facilit ies will be located in rural areas close to feedstock, rather than close to urban fuel markets. Transportation factors to consider as biofuel production continues to expand include:
- The capacity of the transportation system to move biofuel, feedstock, and co-products produced from biofuel, especially over long distances to fuel markets.
- The availability of feedstock close to biofuel plants within 100 miles
- The proximity of feedstocks and biorefineries to co-product markets.
- Uncertainty about the size and location of biofuel demand from terminal s which consolidate, trans load, and distribute biofuels for blending.
Government policies towards biofuels may decrease this uncertainty. The lack of excess transportation capacity reduces flexibility in case of sudden changes in transportation demand and distribution patterns. Changes in these patterns brought on by rapidly increasing biofuel production could impact the logistics of rail networks, highway congestion, and marine logistics.
Co-Product Transportation Issues
Ethanol plants that use corn and other grains as feedstock produce a co-product called distillers grains (DDGS dried distillers grains with solubles, WDG-wet distillers grains, and MDG-modified distillers grains). For every 56-pound bushel of corn, 17.5 p ounds of DDGS and 2.76 gallons of ethanol are produced, on average. Slightly different yields of DDGS are produced from other grains. Dairy cattle operations and cattle feedlots are the primary domestic users of distilled grains as a protein supplement for the ruminant animals. Research is ongoing for increasing the DDGS use by poultry and hog operations, which currently is limited due to nutritional challenges DDGS present to non-ruminant animals. DDGS are initially marketed locally, and delivered by truc k. However, as production grows, access to wider markets may rely on rail or marine transport. Facilities using grain may also choose to adopt fractionation technologies to extract fibre, protein, starch or sweeteners as co-products. These food-grade co-products would also require transportation infrastructure to deliver these products to market.
Biofuel Infrastructure. Managing in an Uncertain Future. Research and Innovation, Position Paper 03 – 2010
At present, biofuel is first sent to blending terminals through tanker trucks, rail cars, and barges, where they are blended with gasoline or diesel and then sent to consumer filling stations via trucks. In the U.S. 67 percent of the ethanol is transported to blending terminals via trucks, 31 percent by rail cars, and 2 percent by barges. Biofuel is also exported through ships to receiving terminals which then blend them with gasoline and then transport them to filling stations using trucks.
The U.S. passed the Energy Independence and Security Act of 2007 (EISA), which required the creation of a Renewable Fuel Standard (RFS) program. The U.S. environmental Protection Agency issued revised RFS effective on July 1st 2010 (called RFS2) that for the first contained specific fuel volume requirements (Figure 3)
Curley, M. 2008. Can ethanol be transported in a multi-product pipeline? Pipeline & Gas Journal 235:34