A 3,000 L glass-lined reactor with a jacket and a mechanical seal, built to the standard model series, costs USD 8,000–14,000 ex-works from China. That spread is not negotiation room. It is the difference between two genuinely different builds, both of which can be quoted honestly from the same one-line duty.
We are KAVORTE, an independent sourcing and engineering office in Zibo, Shandong, in the centre of China's glass-lined equipment industry. We do not own a factory. We specify, audit, inspect and ship glass-lined, stainless steel and PTFE-lined reactors from 50 to 30,000 L, and price is the first question we answer, because a buyer who cannot see where the money goes cannot compare two quotations.
1. What the number includes, and what it does not
Ex-works means the vessel is priced at the factory gate, before it is crated and moved. FOB Qingdao adds inland transport, export packing and customs formalities. CIF adds sea freight and insurance to your port. On a 3,000 L unit those stages are a modest addition to the ex-works figure. On a 20,000 L vessel they are not, because the unit may need a flat rack or breakbulk and the packing becomes a project in its own right.
The price also excludes duty, inland transport at your end, erection and any site modification. Those are your numbers and they do not change when you change supplier, which is exactly why they should be kept out of the supplier comparison.
2. The seven variables that move the price
Two quotations for the same nominal 3,000 L reactor can differ by more than half without either supplier lying. These are the seven things that do it, in the order they usually bite.
- Volume. Cost does not scale linearly with litres. The cost per unit is highest at the small end, because a 50 L vessel carries much the same nozzle, drive and seal overhead as a far larger one. The per-litre rate flattens as the shell grows, and above roughly 5,000 L you are buying steel, wetted surface and heat-transfer area rather than fittings. That is why a 1,000 L and a 10,000 L total are not comparable without knowing the rate behind each.
- Material family. Glass-lined carbon steel is usually the economical answer for inorganic and organic acids, organic solvents and weak bases at various concentrations. It is the wrong answer for hydrofluoric acid, fluoride-bearing media, phosphoric acid at 30 % or above above 180 °C, or strong alkali above pH 12 at 100 °C. Those duties push you to PTFE lining (PFA, PTFE, ETFE F40, ECTFE F30 or FEP F46) or to a stainless shell, and the price follows. Stainless builds run from 304 and 316L up through titanium, duplex stainless, Hastelloy and clad plate, and every step up the alloy ladder is a step up in cost per kilogram of shell.
- Design pressure, temperature and heat transfer. Design pressure in MPa and design temperature in °C set wall thickness, flange rating and closure. A vessel designed for a modest band and one designed for a higher band are different pieces of steel at the same nominal volume. Operating temperature has its own limit, because the lining constrains it: thermal shock resistance is cold shock ≤ 110 °C and heat shock ≤ 120 °C. Jacket, inner coil, immersion tube and half-pipe coil each do a different job at a different cost, and each changes the nozzle layout, the fabrication hours and the shipping weight.
- Agitation and sealing. Paddle, anchor and frame, disc turbine, hydrofoil, impeller or dispersion disc — the agitator, its drive and its seal are frequently the second-largest block in the quotation after the vessel itself. A packed seal and a mechanical seal are not interchangeable. The packed seal costs less and asks for more attention; the mechanical seal costs more and holds pressure and vacuum better. A sterile-grade mechanical seal, a GMP mirror-polished interior or a hygienic no-dead-corner finish each add cost, and each is only worth paying for if your process or your auditor requires it.
- Certification, inspection and documentation. Lining quality is verified, not assumed. The high-voltage test on the finished lining and the measured lining thickness in mm are two numbers you should see on the test record before the vessel is crated. Third-party inspection, material certificates and any project-specific standard your customer has named all add cost and, more importantly, add days to the schedule.
- Lead time. A rush order costs more, and the floor is not set by how fast steel can be cut. The lining stage and the inspection stage have a sequence that cannot be compressed without a reason, and a supplier who shortens it without telling you what was skipped has moved the risk to your plant rather than removed it. Ask what is being shortened, and expect the answer on the schedule.
- Quantity. Two identical vessels cost less per unit than one, because drawing approval, jigs, agitator patterns and freight are shared across the batch. Ordering a spare vessel at the same time as the working one is usually cheaper than ordering it later, and it is the only time both units come off the same approved specification confirmation sheet.
3. When the cheaper build is the right purchase
A packed seal on a vessel running at atmospheric pressure on a non-hazardous medium is not a compromise. It is the correct specification, and paying for a mechanical seal there is money you will never recover. The same logic applies to a standard carbon steel shell with a standard glass lining on a straightforward acid duty, and to a standard model rather than a custom one where the standard already fits your nozzle schedule. The expensive build is justified by a duty, a standard or an auditor — not by preference.
What is never the right purchase is a cheap quotation that does not say which of the seven variables it chose. If two numbers differ and neither quotation breaks out the vessel and lining, the jacket or heat transfer, the agitator and drive, the seal, the nozzle and fitting schedule, and the inspection, then you are comparing a headline with a headline.
4. What we need before we can give you a real number
Send the duty: volume in litres, medium and concentration, operating and design temperature in °C, design pressure in MPa, jacket or coil requirement, agitation requirement, and the standard you are building to. Model designation and nominal volume follow the industry-standard series and nothing else. Internal dimensions, heat-transfer area, agitator power and unit weight all depend on your duty — design pressure, jacket type, sealing arrangement, nozzle layout and any non-standard requirement.
We then issue a numbered specification confirmation sheet, which you approve before fabrication starts. That sheet is what the price is attached to, and it is the document that settles the argument if the vessel that arrives is not the vessel you thought you bought.
5. What to do next
- Write the duty down before you ask anyone for a price. A volume on its own gets you a range, not a quotation.
- Ask every supplier for the same six lines separately: vessel and lining, jacket or heat transfer, agitator and drive, seal, nozzle and fitting schedule, inspection and documentation.
- Ask for ex-works and FOB figures both. The gap tells you how the supplier is packing and where the handling risk sits.
- Use USD 8,000–14,000 ex-works for a 3,000 L jacketed glass-lined reactor with a mechanical seal as your anchor, then move it deliberately for each of the seven variables rather than accepting whichever end of the range you are handed.