Lined Pipe in Decatur and Huntsville, AL

The south bank of the Tennessee River at Decatur carries one of the densest runs of chemical plants in the Southeast: a fluoropolymer complex, a world-scale adiponitrile plant, a terephthalic acid and paraxylene site, a flat-rolled steel mill with its own pickling line, and a film plant. Twenty miles east, Huntsville builds rocket engines and sequences genomes. Both cities move fluids that carbon steel cannot hold. Marspec Technical Products fabricates plastic-lined pipe spools in Fairhope, Alabama and supplies the lined fittings and valves for that service. Call (251) 625-4949.

Send us an isometric, a valve list or a photograph of the failed spool and we will quote a replacement, or contact us online.

What the Decatur riverfront actually runs

Fluorochemistry on Wheeler Reservoir

Decatur has made fluoropolymers for more than a quarter century. One plant of about 400 people produces PTFE and melt-processable fluoropolymer resins, with a $195 million expansion that added monomer and polymer capacity; a neighboring plant makes films. Fluoropolymer production means anhydrous and aqueous hydrofluoric acid, hydrochloric acid byproduct and tetrafluoroethylene monomer. Aqueous HF destroys glass and most metals, and the trace iron that carbon steel sheds ruins resin color. PTFE-lined pipe and PFA-lined valves, which are made of the same chemistry the plant produces, are the standard answer.

Nylon and polyester intermediates

The adiponitrile plant on the river makes the building block for nylon 6,6. Adiponitrile is made here electrochemically from acrylonitrile in an aqueous salt electrolyte, which means acrylonitrile, circulating electrolyte, caustic scrubbing and acid neutralization through every part of the unit. Downstream of it, Decatur's aromatics complex oxidizes paraxylene to purified terephthalic acid in hot acetic acid with a bromide promoter, a combination so corrosive that the reactors are titanium, and the complex is the only commercial source of naphthalene dicarboxylate in the world. Acetic acid recovery, bromide-laden wastewater and catalyst-recovery lines at a PTA plant are PTFE service, with PVDF on the cooler, dilute lines, and a PET film plant next door adds ethylene glycol and caustic cleaning loops.

Steel, metals and the rest of the corridor

The Decatur sheet mill, built for 1.9 million tons a year and pushed toward three million, pickles hot band in hydrochloric acid before cold rolling. Copper wire drawing in Hartselle, aluminum extrusion and anodizing in Decatur and specialty alloy production in Athens all run sulfuric, nitric or mixed acid pickling and caustic etch baths. A carbon fiber plant, a soybean crushing plant with hexane extraction and caustic refining, poultry processing with peracetic acid and CIP chemicals and the municipal water plants that draw on the Tennessee River round out the list.

Huntsville: biotech, aerospace, electronics

Huntsville's process needs look different. The biotechnology campus in Cummings Research Park hosts dozens of associate companies and a large commercial biospecimen and genomics operation. Pharmaceutical and biotech production depends on high-purity water, buffer solutions, solvents and CIP acids and caustics carried in pipe that adds no metal ions, which is what PTFE-lined spools and lined diaphragm valves provide. Many of those solvents can build a static charge that pinholes a plain lining or ignites vapor, so bond and ground the spools and use anti-static PFA-AS valves; tell us if your specification calls for an anti-static liner. The aerospace side, from the rocket engine plant to the engine machining plant that supplies about a third of Toyota's U.S.-built engines, runs anodizing, chemical milling, passivation and plating shops on sulfuric, nitric, chromic and hydrofluoric acid and caustic etch, plus the wastewater treatment those shops require.

The Marspec line for north Alabama

Custom lined spools from 1/2" through 12" and up to 20 ft, lined elbows, tees, reducers and laterals, all fabricated to your isometric in carbon steel or 304 and 316 stainless housings with PTFE, PVDF or polypropylene liners. See the lined pipe and fittings page for liner selection by fluid and temperature.

Lined ball, plug, butterfly, diaphragm, check and sampling valves come in the same flange standards as the pipe. For HF, hot HCl and PTA acetic acid service we recommend PFA-lined valves; for high-purity water and pharmaceutical duty, lined diaphragm valves with no crevices. Our lined valves page lists the types and sizes.

Piping accessories include lined strainers, expansion joints for the thermal growth on long riverfront racks, PTFE spacers and spectacle blinds for isolating lines during a turnaround, sight glasses and solid PTFE pipe. For lines that carry 50 percent caustic, acetic acid, which freezes just above 60 degrees Fahrenheit, or viscous polymer intermediates, we supply clamp-on steam heaters, electric tracing and heat-transfer compound through our temperature maintenance products. For jacketed or traced service, we recommend specifying PTFE.

Specifications we build to

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 passes a spark test at a minimum of 10,000 volts. Liner temperature limits, liner thicknesses, flange dimensions and torque tables are on our technical details page. More than half a century in plastic-lined piping stands behind every spool.

Decatur, Huntsville and the Tennessee Valley

We ship lined pipe to Decatur, Huntsville, Madison, Athens, Hartselle, Priceville, Courtland, Scottsboro, Florence and Muscle Shoals from Fairhope, Alabama, with custom spools fabricated in our own shop. Call (251) 625-4949 or contact us online and tell us what the line carries.

FAQ: Lined Pipe in Decatur and Huntsville, AL

What liner do you recommend for hydrofluoric acid at a Decatur fluoropolymer plant?

PTFE-lined pipe and PFA-lined valves. PTFE is not attacked by HF at the concentrations and temperatures a resin plant runs, though HF permeates it; the carbon steel housing carries the pressure while the liner carries the acid.

Can lined pipe stand up to the acetic acid and bromide in a PTA plant?

Yes. We recommend PTFE-lined pipe for hot acetic acid, since PVDF is limited in hot concentrated acetic; PTFE also covers the bromide-laden recovery and wastewater streams, with PVDF an option on the cooler, dilute lines. Both liners avoid the titanium and high-nickel alloys that bare-metal pipe would require in that service.

Do you supply lined spools for pickling and acid regeneration at the Decatur steel mill?

We supply PTFE- and PVDF-lined spools and PFA-lined plug valves for hydrochloric acid pickling, rinse and acid-regeneration lines, built to match the flange standard of the existing lined system so they drop in during a line outage.

What should a Huntsville biotech or pharmaceutical plant specify for high-purity service?

PTFE-lined spools and lined diaphragm valves. The liner contributes no metal ions, tolerates CIP acids and caustics and the solvents used in purification, and can be supplied in 316 stainless housings where the exterior must be stainless.