Connecting the Pipes

Ethanol plants may vary in design, but they all need one thing: piping. There are different types of piping that connect the many processes within the facility, and each offers its own advantages. Although this equipment is essential it isn't without its challenges when it comes to labor, maintenance, safety, education and cost.
By Jessica Sobolik | July 08, 2008
A typical 100 MMgy ethanol plant could require as much as 95,000 linear feet of piping, depending on the plant design. Fitting all of these pipes together is no easy task. Certain areas of the plant call for different types of piping, mainly welded, threaded, flanged or coupled. Depending on the type of piping, labor could be intense and safety may be a factor. For all types, however, maintenance is necessary, and educating plant owners and operators is the key to keeping piping systems trouble free. EPM looks at the four main types of piping, along with their benefits and challenges.

There are many different ways to connect pipes, and several are used throughout an ethanol plant. One method is welding. This could include simple butt welding (touching two pieces together without overlap and welding the seam), or it could involve welding the ends of flanged pipes together. It's usually a strong bond and the most common within ethanol plants, but there are a couple drawbacks. For one, a welded pipe is hard to take apart. In instances where maintenance is necessary or a part was simply welded incorrectly, it would take additional labor and more time to fix. Furthermore, welders are in scarce supply these days. Still, it's necessary in many applications and is preferred by process technology providers such as Colwich, Kan.-based ICM Inc. and Memphis, Tenn.-based Lurgi Inc.

Threaded piping is cut at the ends so that it can be screwed onto another piece. Mike Kroeker, director of design services for ICM, says it's used mostly around a plant's instrumentation and to transfer air throughout the plant. For regular maintenance, this type of piping is easier to disconnect than welded pieces.

Flanged piping can be connected at the ends via welding, or with eight to 12 bolts and a gasket in the middle, according to Tom Sheeler, vice president and chief operating officer of Cheraw, S.C.-based American Stainless & Supply, which produces this type of piping. ICM uses flanged piping around instruments and valves. If it's bolted and not welded, it can be taken apart after removing the bolts. In areas of ethanol plants that require regular maintenance or cleaning, this type of piping is ideal. Kroeker says flanged pipes are more
rugged and easier for maintenance crews to work with. However, he also acknowledges that they are more expensive, especially for the larger-diameter piping.

Coupled piping connects the ends of pipes with only two bolts and is used almost exclusively in fire suppression systems, according to Kroeker. Mark Aldrich, industrial business development manager for Easton, Pa.-based Victaulic Co., which produces this type of piping, says his company's products have also been used for cooling water, air and reverse osmosis systems, distillation, drying, decanting, and distillers grains handling. He points out that coupled piping can be assembled and disassembled quicker than flanges, thus saving time and labor costs. He also points out that coupling doesn't require welding, which improves plant safety. "We don't require flame on a job site," he says. "The possibility of fires is reduced." This means improved maintainability for ethanol plant operators and owners.

Another benefit of coupled piping is the compressive load capabilities on the gaskets in between connections, according to Aldrich. He says coupled piping has a c-shaped, cross-section seal that is durable and can handle significant compressive and cyclical loading. In other words, operators can pressure and depressurize a system repeatedly for many years without fatiguing the rubber. The rubber seal also accommodates vibrations felt throughout the plant, along with the expansion and contraction that naturally happens in all piping systems. In contrast, Aldrich says welded or flanged piping systems may have rubber bellows or braided flexible hose, which tend to wear out over time and require replacement. Still, Kroeker calls flanges "a slam dunk."

In addition to piping, there is a similar option for connecting processes: welded tubing, which has thinner gauge (wall thickness) compared with piping and is typically used in heat exchangers, according to John Robb, president of Beloit, Wis.-based United Industries Inc., which makes this kind of connection. Kroeker says ICM uses tubing to connect air lines to instruments and control lines because it's flexible.

From Creation to Installation
Companies such as American Stainless & Supply, United Industries and Victaulic produce various pieces of pipes in their shops, but how does the equipment get to ethanol plants across the United States? Piping can range in diameter from two inches to 12 feet or more, making transport a challenge. Therefore, American Stainless & Supply ships its stainless steel and carbon steel pipingmostly welded and flangedin pieces to fabricators such as Granite Falls, Minn.-based Fagen Inc. Fagen has a fabrication facility in Wisconsin, where workers assemble the various pieces of pipes before putting them on trucks and shipping them to ethanol plant sites. United Industries has shipped its stainless steel products to fabricators such as ICM, Poet LLC, Delta-T Corp., Archer Daniels Midland Co. and Wisconsin-based Apache Stainless Equipment Corp. Victaulic has sent its steel pipes to process technology providers Lurgi, Delta-T and ICM. It has also sent products directly to engineers such as SSOE Inc., C.J. Schneider Engineering Co., Ambitech Engineering Corp., Crown Iron Works Co., Burns & McDonnell and JH Kelly. Along with the equipment, it sends representatives to the plant site to train the workers who assemble its piping.

Pipe suppliers meet with engineers and process technology providers often to discuss the benefits of their products. "Once they've used [the products], then [the engineers] usually continue to use them for the same services," Aldrich says. "They put us in the specs, and once we're in there, we work with contractors when they're bidding a job or negotiating, so we're sure they understand what's been done by the engineer."

Typically, once the pipes are installed in an ethanol plant, it's up to the plant owner or operator to service the equipment. However, process technology providers that design the piping structure, such as ICM, usually offer an in-depth training program, and parts and services. "We have a warranty program that would cover material failures during a certain period," Kroeker says. "ICM also has an active customer-oriented aftermarket support and maintenance group that helps plants keep necessary spares and coaches them on what they need." Victaulic also participates in training with the plant owner.

The latest plants to install Victaulic pipes include Cascade Grain Products LLC in Clatskanie, Ore; E3 BioFuels LLC in Mead, Neb.; and NEDAK Ethanol LLC in Atkinson, Neb.

Combating Raw Material Costs
Pipe fitters and suppliers face many challenges in this industry, and most recently the largest hurdleno matter what type of pipinghas been the fluctuating cost of raw materials.

For example, Sheeler says that although stainless steel prices have been stable and nickel prices have dropped lately, the prices of molybdomen and chrome have increased. "So [the cost savings] is offset," he says. In addition, carbon steel prices have gone up 60 percent since Jan. 1, and additional increases are expected. Sheeler says carbon steel price swings were mainly caused by China importing 50 percent of the U.S. carbon steel pipe supply, followed by other foreign countries, creating a demand that domestic producers couldn't meet. That, combined with the devaluation of the U.S. dollar, has caused some suppliers to export their materials. "The worldwide demand for steel is very strong," he says.

Meanwhile, demand for piping in the United States has seemingly stagnated. For example, because of a slowdown in conventional ethanol plant construction, Fagen has been left with a lot of extra equipment on-hand, according to Sheeler. It is currently trying to sell back $20 million worth of equipment at reduced prices, and Sheeler acknowledges that this will hurt his company's distributors. "Ethanol was gangbusters for awhile, and now it's almost come to a halt," he says.

Victaulic, a huge buyer of scrap steel, has also been affected by the fluctuating cost of raw materials, according to Aldrich. However, he points out that because his company is reducing necessary labor and materials, it can still provide a 25 percent cost savings to its customers. "Using our systems, we reduce labor by 50 percent to 75 percent compared with traditional piping systems," he says. With less manpower required, it also takes less time to install the piping systems. "If it was going to take 12 months to build a plant, you might shave a month off," Aldrich says.

Optimizing Plant Design
As previously mentioned, the amount of piping in an ethanol plant varies by plant design. Carlos Lange, executive vice president of Lurgi, says his company uses approximately 51,000 linear feet in a 55 MMgy ethanol plant and 95,000 linear feet in a 105 MMgy facility. ICM, on the other hand, uses approximately 50,000 linear feet in a 50 MMgy ethanol plant and 66,000 linear feet in a 100 MMgy facility, according to Kroeker. This number has varied from year to year as ICM engineers sit down annually to review its plant design. "We're looking for maximum piping economy to make these plants as affordable to build as possible without sacrificing safety," Kroeker says. "So we carefully examine any opportunity we have to minimize the number of pipe fittings, which translates into the price of fittings and reduces the number of welds." Lange says Lurgi also optimizes its plant designs to reduce piping quantities.

When It Comes to Cellulose
These types of piping work well in conventional ethanol plants, but suppliers have noticed the recent slowdown in construction. However, more cellulosic ethanol plants are on drawing boards nationwide. Is there a market for the same pipes in that type of facility? Absolutely, Aldrich says. "We tie together all the pieces of process equipment," he says.

Kroeker says as long as the various cellulosic processes explored thus far don't change, piping specifications should stay the same. "We don't think there's going to be a lot of radical changes," he says. "We haven't found anything yet that requires exotic materials."

Lange agrees. "In general, I do not see much change in the piping requirements as we move to cellulosic ethanol," he says. "When cellulose is converted to a starch stream and processed into ethanol, the general piping requirements stay the same as a typical corn facility."

In general, pipes require relatively low maintenance, Kroeker says. They are used in different ways in different areas of a plantbut they are fairly versatile. On another level, Aldrich points out that pipes do more than simply connect processes. "Honestly, I don't view us as trying to move couplings," he says. "We are really bringing to the industry a faster schedule, less cost and more safety. That's really the end result."

Jessica Sobolik is the Ethanol Producer Magazine managing editor. Reach her at or (701) 373-0636.