Lined Pipe in Iowa

Iowa grows more corn than any other state and turns more of it into ethanol than anyone else, which makes it one of the heaviest users of sulfuric acid, caustic soda and clean-in-place chemicals in the Midwest. Corn wet mills, biodiesel plants, nitrogen fertilizer complexes, packing plants and municipal water utilities round out an industrial base that runs on corrosive fluids from one end of the state to the other.

Marspec Technical Products has fabricated plastic-lined piping for more than half a century. We build PTFE-, PVDF- and polypropylene-lined steel pipe spools and fittings from 1/2" through 12" in Fairhope, Alabama, supply a full line of lined valves and accessories, and ship nationwide. Iowa plants can reach us at (251) 625-4949 or contact us online.

The biofuel state

Iowa leads the nation in both ethanol and biodiesel production, with dozens of dry-grind ethanol plants spread across the corn belt from the Missouri River to the Mississippi. A dry-grind plant uses sulfuric acid to hold mash pH, 50 percent caustic and acid blends to clean fermenters and heat exchangers, ammonia or urea as a yeast nutrient, and hypochlorite or chlorine dioxide in cooling water. The thin stillage and evaporator circuits concentrate chlorides and organic acids that pit stainless over time, and the evaporators themselves run under vacuum. Biodiesel plants add methanol, sodium methylate catalyst, sulfuric or hydrochloric acid for glycerin acidulation and salty crude glycerin. PTFE-lined pipe carries every one of those streams, and PVDF-lined pipe all but the caustic, the methylate and anhydrous ammonia, which PVDF is not rated for. Polypropylene-lined pipe is available for caustic and dilute acid where a specification calls for it, and lined ball and diaphragm valves give operators tight shutoff on chemical feed skids.

Corn wet milling on the Cedar and the Mississippi

Cedar Rapids is one of the largest corn-processing cities in the world, home to cereal, starch, sweetener and bioproduct plants. Clinton, Muscatine and Eddyville host similar complexes, and the Fort Dodge area combines corn processing with chemical manufacturing. Wet milling steeps corn in sulfur dioxide water, converts starch with hydrochloric acid or enzymes, refines sweeteners through carbon and ion-exchange beds regenerated with acid and caustic, and ferments dextrose into lysine, lactic acid, citric acid and ethanol. Sulfurous acid and hot organic acids attack steel and discolor products that touch corroding stainless, which is exactly the problem a plastic liner removes. Our lined pipe and fittings run from the steep tanks to the fermenters without adding a trace of iron to a food-grade product.

Nitrogen fertilizer, meatpacking and water

Iowa's demand for nitrogen has drawn world-scale ammonia and urea production to the state, with large complexes at Port Neal south of Sioux City and at Wever on the Mississippi in southeast Iowa, plus an older plant at Fort Dodge. The ammonia itself runs in steel, the nitric acid and ammonium nitrate solution usually in 304L stainless and the UAN in inhibited carbon steel, but the hot, contaminated or mixed streams, the demineralizer regeneration acid and caustic, and the cooling tower chemical feed around those plants belong in lined pipe. The state's packing plants, with more than 22 million hogs in the state at any time and major beef and pork operations at Sioux City, Waterloo, Storm Lake, Denison, Ottumwa and Columbus Junction, clean with caustic, hypochlorite and peracetic acid every night and treat high-strength wastewater with ferric chloride and polymer. Municipal water utilities in Des Moines, Cedar Rapids and the river cities run nitrate removal, softening and disinfection systems that consume salt brine, sodium hypochlorite, ferric chloride and fluorosilicic acid in quantities that justify lined piping on every feed line.

What Iowa plants order from Marspec

Custom lined spools up to 20 ft, in carbon steel or 304/316 stainless housings, with PTFE, PVDF or polypropylene liners chosen for the service. Lined elbows, tees, reducers, laterals and instrument tees that conform dimensionally to ANSI B16.5. Lined ball, plug, butterfly, diaphragm, check and sampling valves. Lined strainers, expansion joints, flange spacers, spectacle blinds and sight glasses, plus solid PTFE pipe. And for the outdoor caustic, hypochlorite and ferric chloride lines that an Iowa January will freeze, clamp-on steam heaters, electric heat tracing and heat-transfer compound that keep the line flowing. For jacketed or traced service, we recommend specifying PTFE.

Built and tested to spec

Our lined pipe and fittings comply with ASTM F1545. Fittings conform dimensionally to ANSI B16.5 and are welded to ASME B31.3 by welders certified to ASME Section IX, and every lined pipe spool and fitting is spark tested at a minimum of 10,000 volts. Liner temperature limits, liner thicknesses, flange dimensions and torque tables are on our Technical Details page, and the rest of the catalog is under Other Products.

Serving Cedar Rapids, Des Moines, Sioux City, the Quad Cities and beyond

We ship lined pipe and valves to Cedar Rapids, Iowa City, Davenport and the Quad Cities, Clinton, Muscatine, Burlington, Keokuk and Fort Madison, Des Moines, Ames, Fort Dodge, Mason City, Waterloo, Dubuque, Ottumwa, Eddyville, Sioux City, Council Bluffs, Storm Lake and Denison. Call (251) 625-4949 or contact us online with a line list, and we will quote it.

FAQ: Lined Pipe in Iowa

Which liner should an Iowa ethanol plant use for sulfuric acid and CIP caustic?

PTFE for both: it handles sulfuric acid at every concentration and temperature the plant runs, 50 percent caustic and the dilute acid blends, so the acid skid and the CIP header share one liner specification. PVDF is an option on the acid side only for cooler, dilute acid, and polypropylene is available for the caustic and dilute acid lines where a specification calls for it.

Can lined pipe handle the steep water and organic acids in a Cedar Rapids corn wet mill?

Yes. Sulfur dioxide water, lactic and citric acid and hydrochloric acid are all within the ratings of PTFE and PVDF liners, and the liner keeps iron and chromium out of food-grade product streams.

Do you supply lined piping for nitrate removal and hypochlorite systems at Iowa water utilities?

We do. Brine regeneration lines, sodium hypochlorite feed and ferric chloride feed are standard applications for PTFE- and PVDF-lined pipe with lined diaphragm valves, or ball valves with a vented ball (vent facing upstream) on the hypochlorite, and we fabricate the spools to your isometrics. On commercial 12.5 percent hypochlorite, which carries excess caustic at about pH 12 to 13, PTFE is the liner we recommend; PVDF suits dilute or lower-pH hypochlorite.

How do you keep an outdoor ferric chloride or caustic line from freezing at an Iowa packing plant?

We supply clamp-on steam heaters and electric heat tracing with heat-transfer compound that mount on the outside of the lined spool, holding the line above its freezing or crystallization point. For jacketed or traced service, we recommend specifying PTFE. Keeping the liner inside its rating, even when the line is not flowing, depends on sizing the steam pressure or tracer output, and we need your application data to make that recommendation.