Corrosion Resistant Titanium Heat Exchanger for Chlor-Alkali Industry

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Проверено и поддерживается инженерной командой Shaanxi Qianyi Tuoda Technology Co., Ltd.

Corrosion Resistant Titanium Heat Exchanger for Chlor-Alkali Industry | Gr2/Gr7/Gr12, ASTM B338, ASME VIII

Meta Description: Corrosion resistant titanium heat exchanger for chlor-alkali industry — wet chlorine, brine electrolysis, caustic evaporation and hypochlorite duty. Gr2 for oxidizing brine and wet Cl₂, Gr7 (Ti-0.2Pd) for hot crevice and reducing segments, Gr12 for hot brine strength. ASTM B338 tubes, ASME VIII + TEMA, PMI per heat, EN 10204 3.1, 3.2 TPI PO-fronted.

Chlor-Alkali Is Not One Stream — It Is Three

Chlor-alkali plants run three corrosive streams at once, and titanium does not handle them identically:

• Wet chlorine side — saturated Cl₂ + H₂O + hypochlorous acid; oxidizing, aggressive, moisture-dependent
• Brine side — 200–300 g/L NaCl, aerated or deaerated, hot, scaling, crevice-rich
• Caustic side — NaOH 32–50%, hot, with a hard temperature ceiling for titanium (and a different ceiling for nickel)

Specifying "titanium heat exchanger" without naming the side and the temperature is not engineering — it is hope. We grade by side, by temperature, and by oxidation state.

Grade Selection by Chlor-Alkali Segment

The most common chlor-alkali mistake: putting titanium on the hot caustic evaporator. Titanium resists wet chlorine and brine; it does not resist hot concentrated NaOH. Above 315°C, that job belongs to Nickel 201 (C≤0.02%).

Why Gr7 Earns Its Place in Chlor-Alkali

• Gr2 crevice threshold in chloride ≈ 80°C; above that, stagnant crevices can localize
• Gr7 (0.12–0.25% Pd) holds passive film in deaerated/reducing chloride — crevice corrosion threshold extended dramatically
• In cell-room cooling and hot brine heaters, deposits + low-flow dead legs are unavoidable → Gr7 is the insurance
• HCl acid-regeneration segments: Gr7 resists far higher HCl concentration/temperature than Gr2

Design & Code Baseline

• Code: ASME BPVC Section VIII Div.1; TEMA Class R/C/B per duty
• Tube: ASTM B338 Gr2/Gr7/Gr9/Gr12, seamless or welded (weld on neutral axis for U-bend)
• Tubesheet: ASTM B265 Gr2/Gr7, integral or loose-lined; explosively/clad optional
• Shell/heads: titanium-lined carbon steel or full titanium per pressure & cost target
• Joint: hydraulic roll → orbital TIG weld, argon backing ≥99.999%, dye-penetrant on critical welds
• U-bend radius: 1.5–2×OD (≤25mm), 2–2.5×OD (>25mm); mandrel bend, PT after bend
• Corrosion allowance: typically zero for titanium — lifecycle cost is in the uptime, not the wall

Typical Duty Window

QC & Traceability

1. ASTM B338 tube MTC EN 10204 3.1 — heat-specific chemistry + tensile + flatten/flare (seamless) or reverse-flatten (welded)
2. Eddy-current or hydrostatic per B338 election (state which on PO)
3. PT on U-bend + tubesheet welds
4. PMI on tubes/tubesheet (grade verification, not tag trust)
5. Heat No. = tube tag = MTC = fabrication weld map
6. Hydro test per ASME VIII; passivation/cleaning validated (no Fe contamination)
7. 3.2 (SGS/BV/TÜV/DNV) TPI PO-fronted for PED/offshore/mega-project

Anti-Fouling & Operability Notes (real, not marketing)

• Titanium resists corrosion, not scaling — brine scaling needs side-stream softening, periodic acid wash, or velocity control
• Design velocity 1.5–2.5 m/s tube-side to limit deposit; confirm with process licensor
• Acid wash chemistry must be approved: no HF / fluoride cleaners on titanium surfaces
• Dry chlorine excursion → separate review; titanium wants moisture to stay passive
• Galvanic contact with carbon steel in reducing brine → isolate / insulate

Hard Boundaries (no overclaim)

• HF and fluoride-bearing streams attack TiO₂ film — zirconium/C-276/PTFE-lined review required
• Gr2 not for hot deaerated reducing acid — that is Gr7/Gr12 territory
• Titanium is not for hot concentrated caustic evaporator — Nickel 201 only
• Dry chlorine (<0.5% H₂O) excluded — moisture required for passive film
• 3.2 cannot be back-issued; TPI named at PO

RFQ Template (copy-paste)

Process step: wet Cl₂ cooler / brine heater / hypochlorite / cell-room / caustic cooler ___
Side: tube-side ___ / shell-side ___
Chemistry: Cl₂ ___%, NaCl ___g/L, NaOH ___%, pH ___
Max tube-wall temp: ___°C (upset excursion ___°C)
Aerated / oxidizing vs reducing: ___
Scaling tendency: yes/no, scale type ___
Duty: heating/cooling/evaporation, Q = ___kW
Tube: ASTM B338 Gr___, OD×wall ___, straight / U-bend qty ___
Tubesheet: Gr___, integral / loose / clad ___
Shell: titanium / Ti-lined CS ___
Code: ASME VIII Div.1 + TEMA Class ___
Joint: roll / weld / roll+weld ___
Cert: 3.1 / 3.2 TPI (SGS/BV/TÜV ___)
Cleaning chem (CIP/acid wash): ___ (NO HF confirmation ___)
Incoterm: EXW / FOB / CIF / DAP ___

FAQ — Titanium Heat Exchanger for Chlor-Alkali

Q1: Is Gr2 enough for chlor-alkali?
A: For wet chlorine, hypochlorite, and aerated brine — yes. For hot deaerated crevices and reducing acid wash — Gr7/Gr12.

Q2: Why not just thicken Gr2 instead of upgrading to Gr7?
A: Wall thickness does not fix crevice electrochemistry. Hot deaerated chloride attacks the passive film locally; Gr7 changes the potential. Thicker Gr2 still pits in the gap.

Q3: Can titanium handle the acid wash?
A: Gr7/Gr12 handle reducing HCl/H₂SO₄ wash within defined concentration/temperature windows. No HF. Wash recipe must be on the RFQ.

Q4: Welded tube or seamless?
A: Both B338-valid. Welded with annealed seam + reverse-flatten is cost-effective for most bundles; seamless when spec mandates or high-vibration duty. Say which on PO.

Q5: Can titanium be used on caustic evaporator?
A: No. Hot concentrated caustic above 315°C is Nickel 201 territory. Titanium is for wet chlorine and brine sides.

Q6: ASME + TEMA deliverable?
A: Yes — VIII Div.1 calc package, TEMA sheet, weld map, MTC 3.1, hydro + ET, PT on welds.

Q7: How long is service life?
A: In confirmed oxidizing chloride, 20+ years is normal. Life is decided by cleaning discipline and fluoride exclusion, not by the alloy alone.

Q8: Can you supply tube-only or full exchanger?
A: Both — B338 tube bundles only, or turnkey shell-and-tube with titanium tubesheet and lined shell.

Q9: HS code?
A: Exchanger unit and bare tube follow different headings; Broker confirms by configuration/destination.

Q10: Biggest EPC mistake?
A: Specifying "titanium exchanger" with no segment chemistry. Gr2 bought for a hot caustic evaporator = repeat failure. The PO must name the grade per pass.

Request a Quote

Email: sales@[yourdomain].com

Send process segment + chemistry + max temp + duty + tube spec + code level. We return grade-per-pass recommendation, not a one-grade-fits-all quote.

About: Baoji titanium heat-transfer desk for chlor-alkali — shell and tube exchangers and B338 tube bundles in Gr1/Gr2/Gr7/Gr9/Gr12. Grade assigned per process segment (wet Cl₂ / brine / hypochlorite / cell-room / caustic cooler), ASME VIII + TEMA, rolled-welded tubesheet, PMI per heat, EN 10204 3.1, 3.2 TPI PO-fronted. No fluoride service, no Gr2-in-hot-crevice substitution, no broken heat chain. Heat No. = tube tag = MTC = weld map.