Lined Pipe for Pharmaceutical and Fine Chemical Plants

Pharmaceutical and fine chemical plants have two requirements that bare steel cannot meet at once: the pipe must survive bromine, thionyl chloride, hot acid, caustic and every common solvent, and it must leave nothing behind, because a trace of iron colors a batch or fails an elemental impurities assay. Marspec Technical Products fabricates PTFE-, PVDF- and polypropylene-lined pipe spools, supplies PFA- and PTFE-lined valves and accessories, and supplies glass-lined reactors, columns and pipe for the reactor train. Call 251-625-4949 to talk through a reactor train.

After more than half a century in plastic-lined piping, we can usually recommend a liner from the chemistry and the temperature. Contact us online with a line list.

Fine chemical synthesis: three product families

Active pharmaceutical ingredients

An API plant builds the active component of a prescription or over-the-counter drug through a sequence of batch steps: bromination with bromine or N-bromosuccinimide, chlorination with thionyl chloride or phosphorus oxychloride, acid chloride formation that throws off hydrogen chloride and sulfur dioxide, Grignard and organolithium couplings in anhydrous tetrahydrofuran quenched with aqueous acid, and salt formation with HCl or HBr in alcohol. The streams between those steps are wet HCl and HBr, dichloromethane, toluene, methanol, acetic acid and the caustic liquor from the off-gas scrubbers. Reactors are glass-lined; the transfer lines, solvent recovery headers and scrubber loops are PTFE-lined steel with PFA-lined valves, in vented housings because HCl and HBr permeate slowly through any fluoropolymer.

Advanced intermediates

Intermediate plants make the building blocks that API and agrochemical producers assemble into larger molecules. Nitration in mixed nitric and sulfuric acid, diazotization in cold hydrochloric acid, Friedel-Crafts acylation with aluminum chloride, sulfonation with oleum and hydrolysis in hot caustic or acid are the typical steps, and the spent acid, quench water and solvent recovery that follow each one are the corrosive services. An intermediate is sold on purity, so iron pickup is a specification failure, and the same glass-lined reactor and PTFE-lined piping arrangement holds.

Agrochemicals

Crop-protection actives lean on phosphorus and sulfur chemistry as well as halogenation: phosphorus trichloride and oxychloride for organophosphates, phosphorus pentasulfide for thiophosphates, chlorosulfonic acid for sulfonyl chlorides, cyanuric chloride for triazines and chloroacetic acid for phenoxy herbicides. Every one of those reagents hydrolyzes to hydrogen chloride on contact with moisture, so the reactor trains, HCl absorbers and caustic scrubbers run on glass and fluoropolymer, with solvent recovery under vacuum behind them. Many agrochemical plants sit inside chlor-alkali and chemical complexes and draw chlorine, caustic and HCl across the fence.

Biologics and the clean side of the plant

Chromatography buffers carry sodium chloride up to one or two molar, which pits 316L, and protein A columns are cleaned with 0.1 to 0.5 molar sodium hydroxide. Clean-in-place cycles push one to two percent caustic at 140 to 180 F followed by phosphoric or nitric acid through the headers. Decontamination uses hypochlorite or peracetic acid, kill tanks inactivate biowaste with caustic or heat, and neutralization follows. The product path is electropolished stainless tubing; the chemical supply side, from the 50 percent caustic and acid totes through CIP distribution and waste neutralization, is where PTFE-lined spools in 316 stainless housings and PFA-lined diaphragm valves belong, because they take the full pH swing and shed no iron, chromium or nickel. Water for injection and purified water want a liner that adds no metal ions; PFA and PTFE qualify.

Glass-lined reactors, columns and pipe

Glass-lined steel is the reactor-train standard here for two reasons: a borosilicate glass fused to a carbon steel shell resists hydrochloric, sulfuric and nitric acid across the concentration range, bromine chemistry, organic acids and solvents, and its smooth surface cleans easily with no metal touching the batch. We supply glass-lined reactors, columns, receivers, heat exchangers and Nutsche filters, glass-lined pipe and fittings with split-ring loose flanges in ASME B16.5 class 150 and 300 or DIN 2873 drilling, and reglassing of existing equipment. Glass has limits: never hydrofluoric acid or any fluoride-bearing stream; not hot concentrated phosphoric acid; not hot strong caustic, where alkaline attack begins above roughly pH 12 at temperature; and no thermal shock or mechanical impact. That is why the complement to a glass-lined reactor is PTFE-lined pipe and PFA-lined valves on the transfer lines, which take field fit-up and bolting loads. See glass-lined pipe and equipment under our other products, or the glass-lined pipe and equipment page.

Lined transfer lines, valves and the spool package

PTFE is the liner for nearly everything in a synthesis plant because PVDF is attacked by ketones, esters and amines and polypropylene by aromatic and chlorinated solvents; PTFE carries the caustic scrubber liquor and neutralized waste too, PVDF earns its place on purified water and hypochlorite, and polypropylene is available for cool alkaline lines where a specification calls for it. A typical package is 1" through 4" PTFE-lined spools in 316 stainless housings, built to the isometric in lengths up to 20 ft with class 150 ANSI B16.5 rotating flanges that line up with split-ring glass nozzles, plus matching lined fittings. PFA-lined diaphragm valves give a drainable, cavity-free shutoff; PFA-lined ball valves handle solvent transfer; PTFE-lined plug valves isolate HCl and acid; lined sampling valves draw mother liquor without opening the line. PTFE-bellows expansion joints at the reactor nozzles keep piping strain off the glass, solid PTFE dip pipes and spargers go into the vessels, and PTFE spacers and spectacle blinds give positive isolation. See our lined pipe and fittings and lined valves pages.

Solvent recovery runs under vacuum, and PTFE liners are rated for vacuum by size and temperature; the ratings are on our technical details page. Glacial acetic acid freezes at 62 F and 50 percent caustic crystallizes near 54 F, so outdoor acetic acid and caustic lines get electric tracing or clamp-on steam heaters with heat-transfer compound, and viscous or crystallizing streams can run in steam-jacketed lined pipe from our temperature maintenance line, inside the liner's rating.

Where the industry is, standards and ordering

Pharmaceutical manufacturing is densest along the Route 1 and I-287 corridors of New Jersey, in the Research Triangle of North Carolina, along I-495 in Massachusetts, around Indianapolis and in the King of Prussia and Philadelphia cluster. Fine chemical and agrochemical synthesis follows the chemical corridors, including crop-protection chemistry at St. Gabriel on the Baton Rouge corridor.

Our lined products 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 part is spark tested at a minimum of 10,000 volts, so no pinhole reaches the batch. Call 251-625-4949 or contact us online with drawings; custom spools ship from Fairhope, Alabama.

FAQ: Lined Pipe for Pharmaceutical and Fine Chemical Plants

Why pair glass-lined reactors with PTFE-lined piping instead of using one material throughout?

Glass gives a reactor a smooth, inert, cleanable surface that handles acids, halogens and solvents at scale, but it is brittle and cannot carry piping strain or thermal shock. PTFE-lined steel pipe and PFA-lined valves tolerate field fit-up, vibration and bolting loads, resist the same chemistry and add no metal ions, so the two are specified together.

Can you line pipe for the HCl and HBr off-gas scrubber loop on a bromination train?

Yes. PTFE-lined spools in vented housings with PTFE-lined plug or PFA-lined ball valves, because wet HBr and HCl attack nearly every alloy and permeate slowly through any liner. The caustic scrubber liquor itself runs in PTFE as well; polypropylene is available for it where a specification calls for it and the liquor stays cool.

Our biologics plant runs CIP with hot caustic and phosphoric acid. Which liner?

PTFE, usually in a 316 stainless housing for the clean area. It takes the hot caustic, the acid and the chloride buffers in the same line and sheds no iron, chromium or nickel. PFA-lined diaphragm valves give a drainable shutoff on the chemical supply side.

Do you reglass existing reactors and supply glass-lined pipe to match?

We do. Reglassing of existing glass-lined vessels is a service we quote, and we supply glass-lined pipe and fittings with split-ring flanges in ASME B16.5 class 150 and 300 or DIN 2873 drilling to tie into either. Glass is never used on hydrofluoric acid or fluoride-bearing streams and is kept off hot strong caustic; for those lines we quote fluoropolymer-lined pipe.