Lined Pipe in Chattanooga, TN

Two plants on the Hiwassee River at Charleston, in Bradley County, set the tone for corrosive service around Chattanooga: a membrane-cell chlor-alkali plant making chlorine, caustic soda, potassium hydroxide, bleach, hydrochloric acid and hydrogen, and the polysilicon complex beside it, built for about 2.5 billion dollars on 550 acres, that turns silicon metal and hydrogen chloride into hyperpure silicon. Downriver sit Chattanooga's foundry, graphite and consumer health plants and, over the Georgia line, the Dalton carpet mills. Marspec Technical Products fabricates the plastic-lined pipe spools and supplies the lined fittings and valves this corridor needs, with spools shipping from Fairhope, Alabama. Call (251) 625-4949.

Send a valve list, a spool drawing or a photo of the failed part and we will quote a replacement, or contact us online.

Charleston: chlorine on one side of the fence, silicon on the other

The chlor-alkali plant replaced its mercury cells with membrane cells in a 160-million-dollar rebuild sized for about 200,000 tons, with an emphasis on potassium hydroxide. The cells run on purified brine and produce wet chlorine, caustic that is evaporated to 50 percent, and hydrogen, and part of the chlorine becomes hypochlorite and hydrochloric acid. Wet chlorine, hypochlorite and HCl justify lined pipe more often than any other fluids: PTFE-lined spools carry them without titanium, nickel alloys or rubber linings, with PFA-lined ball valves on the HCl, vented-ball valves on the chlorine gas, and lined diaphragm valves or ball valves with a vented ball (vent facing upstream) on the hypochlorite; lined plug valves handle brine and caustic.

Next door, the polysilicon plant reacts metallurgical silicon with hydrogen chloride to make trichlorosilane, purifies it and deposits silicon on heated rods, with capacity above 20,000 metric tons a year. The main byproduct, tetrachlorosilane, goes back into the loop or to a 13,000-ton-a-year pyrogenic silica plant. Dry chlorosilanes travel in steel, but the moment they meet water they hydrolyze to hydrochloric acid and silica, so the vent scrubbers, caustic scrubbing loops, acid-water collection, HCl absorption and neutralization around every chlorosilane unit are lined-pipe service.

Chattanooga: iron, graphite, batteries and consumer health

Chattanooga's own plants are a collection of corrosive utilities. The iron foundry that casts gate valves and the automotive stamping plants run acid pickling, phosphate and zirconium pretreatment, e-coat and caustic cleaning baths with rinse water that must be neutralized. A synthetic graphite plant that makes battery anode material brings scrubber and process water chemistry. The consumer health plant, with about 700 full-time employees, and the bakery in Collegedale, with more than 3,000, clean process equipment with nitric and phosphoric acid and hot caustic in CIP loops. The vehicle assembly plant here runs paint-shop pretreatment on a 5,000-employee scale. In Cleveland, an alkaline battery plant that has run since 1964 fills cells with potassium hydroxide electrolyte, the same KOH made a few miles away on the Hiwassee.

The river plants and the carpet mills over the line

The Citico plant treats Tennessee River water for the city. Moccasin Bend treats an average of about 65 million gallons a day with high-purity-oxygen activated sludge, is rated for 140 million gallons hydraulically, has replaced chlorine gas with sodium hypochlorite and sodium bisulfite, and serves about 400,000 people.

In Dalton, the carpet and flooring mills run their own process chemistry. Carpet finishing is dye chemistry, acids and alkalis for pH control, latex and polyurethane backing and hypochlorite, and a specialty surfactant and polymer maker headquartered in Dalton supplies the industry from a plant in Whitfield County. Those dosing and wastewater lines are PTFE or PVDF service, with PTFE on the caustic and full-strength hypochlorite feeds.

What ships to the Chattanooga corridor

• Custom lined spools, 1/2" through 12" and up to 20 ft, PTFE, PVDF or polypropylene lined, carbon steel or 304/316 stainless housings, with matching lined elbows, tees, reducers and laterals
• PFA-lined ball and plug valves for HCl and caustic, and with a vented ball or plug for chlorine gas; lined diaphragm valves or ball valves with a vented ball (vent facing upstream) for hypochlorite; lined diaphragm valves for throttled dosing; lined butterfly, check and sampling valves
• Lined strainers, expansion joints, PTFE spacers and spectacle blinds, sight glasses and solid PTFE pipe
• Clamp-on steam heaters, electric tracing and heat-transfer compound for 50 percent caustic and 50 percent potassium hydroxide lines that crystallize in a cold snap; for jacketed or traced service, we recommend specifying PTFE

Match the liner to the fluid: PTFE for wet chlorine, HCl, chlorosilane scrubber effluent, caustic, brine, hypochlorite, neutralized wastewater and high-purity water, PVDF for dilute or on-site hypochlorite at pH 12 or below and utility deionized water, and polypropylene for the dilute caustic and dechlorinated brine lines where a specification calls for it. 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 the technical details page, backed by more than half a century in plastic-lined piping.

Chattanooga, Cleveland, Charleston and Dalton

We serve Chattanooga, Cleveland, Charleston, Athens, Soddy-Daisy, Collegedale, South Pittsburg, Dalton, Calhoun, Rome and Fort Oglethorpe from Fairhope, Alabama. Call (251) 625-4949 or contact us online with your spool package or valve list.

FAQ: Lined Pipe in Chattanooga, TN

Which lined valves fit the chlorine, caustic and bleach streams at a Bradley County chlor-alkali plant?

PFA-lined ball valves with a vented ball for wet chlorine gas isolation, lined diaphragm valves or ball valves with a vented ball (vent facing upstream) for hypochlorite, PFA-lined plug valves for 50 percent caustic and potassium hydroxide, and lined diaphragm valves for throttled bleach dosing. All are flanged to the same standard as our lined spools so the run is consistent from the cell room to the loading rack.

Where does lined pipe belong at the Charleston polysilicon site if the chlorosilanes run in steel?

Everywhere the chlorosilanes meet water: vent and emergency scrubbers, caustic scrubbing loops, HCl absorption, acid-water collection and neutralization. Hydrolysis produces hydrochloric acid, and PTFE-lined spools and PFA-lined valves handle it in any concentration.

Can you supply PVDF-lined spools for sodium hypochlorite at Moccasin Bend or the Citico plant?

Yes, for dilute or on-site hypochlorite at pH 12 or below. PTFE-lined spools with lined diaphragm valves or ball valves with a vented ball (vent facing upstream) are our recommendation for full-strength hypochlorite feed, since commercial 12.5 percent bleach carries excess caustic at about pH 12 to 13 that attacks PVDF over time, and PTFE or PVDF suits the bisulfite dechlorination and coagulant lines; the liner keeps metal ions out of the bleach and holds up to the hypochlorite that pits stainless.

Do you build lined spools for the Dalton carpet mills and their chemical suppliers?

We do. Dye, latex, surfactant and pH-control chemistry runs well in PTFE- or PVDF-lined spools, with PTFE on the caustic, and lined diaphragm valves or ball valves with a vented ball (vent facing upstream) handle the hypochlorite. Send the fluid list and line sizes and we will quote a package, with spools and valves shipping from Fairhope.