Technology Zone
Fluid storage holds liquids and gases safely between process steps. This zone covers tanks, vessels, containers, tank equipment and the monitoring and safety systems around them.
Latest in this zone
Alfa Laval Aalborg Header-Coil A/S, a joint venture between heat exchanger manufacturers Alfa Laval and Aalborg CSP, has launched its first product in energy storage. The header-and-coil heat…
Promoted videos
What this zone covers
Pressure, temperature and the vapour pressure of the product decide the shape before anything else. Atmospheric products sit in fixed roof tanks; anything that breathes expensively or dangerously goes into a floating roof or an internal floating roof; liquefied gases and volatile solvents move to pressure vessels, spheres or bullets. Everything after that, the material, the coating and the insulation, follows from the product and the climate.
A fixed roof tank breathes with every fill, every empty and every warm afternoon, and each breath takes product out and air in. A nitrogen blanket with a regulator and a relief keeps oxygen away from the product and the product away from the atmosphere; a vapour recovery unit puts the value back. The pressure and vacuum vent is the safety device that makes all of it survivable, and it is an inspection item.
A bund sized for the largest tank plus rainfall is the last line, not the first. Ahead of it sit an independent high level switch, an alarm the operator cannot silence and forget, and a fill procedure that does not rely on someone watching a gauge. Most large spills are traced back to a level measurement shared between control and protection, which is exactly the arrangement a safety review removes.
Not all storage is a tank. Intermediate bulk containers, drums and portable tanks carry a large share of chemicals, and they bring their own rules: stacking limits, compatibility of the liner with the product, UN approval and a service life. The transfer points, the couplings and the grounding are where the incidents happen, not the container itself.
Storage fails slowly. Bottom plate corrosion, settlement of the foundation, coating breakdown at the liquid line and water accumulating under the product all take years and give little warning from the control room. Formal inspection to a recognised standard, with thickness readings and a settlement survey, is what turns those into planned work instead of an emergency.
| Parameter | Typical range | Rule of thumb |
|---|---|---|
| Bund capacity | 110 % of the largest tank, or 25 % of the total | Check the local rule and add rainfall; the number is not universal |
| Vent sizing | Sized on the maximum fill and empty rate plus thermal breathing | Fire case usually sets the size, not the normal operation |
| Nitrogen blanket pressure | 5 to 20 mbar above atmospheric | Too high wastes nitrogen through the vent, too low lets air in on cooling |
| Fill velocity for static-prone products | Below 1 m/s until the inlet is submerged, then up to 7 m/s | Splash filling a low conductivity solvent builds charge; fill from the bottom |
| Freeboard and overfill margin | High high level at least one fill minute below the vent | Size the margin on how long it takes to stop the pump, not on the trip point |
| Shell thickness inspection | External every 5 years, internal every 10 to 20 | Interval follows the standard and the corrosion rate, not the calendar |
| Insulation and heating | Maintain 5 to 10 degrees above the pour point | Measure at the coldest corner of the tank, not at the outlet |
| IBC stacking | Two to three high depending on the design | Check the rating with product in, not the empty stacking figure |
| Symptom | Likely causes | What to do |
|---|---|---|
| Tank breathes product to atmosphere on warm days | No blanket, vent set too tight, or a fixed roof on a volatile product | Add or correct the nitrogen blanket, check the pressure and vacuum vent settings, and consider an internal floating roof |
| Vacuum damage to the shell after emptying | Vacuum vent blocked or frozen, or an emptying rate faster than the vent can pass | Inspect and free the vent, size it on the real pump-out rate, and never blank a vent for a pressure test without a procedure |
| Water in the product bottom | Condensation from breathing, a leaking heating coil, or rain entering at the roof seal | Dip for water, pressure test the coil, inspect the roof and the seal, and drain on a routine |
| High level alarm did not stop an overfill | Alarm and control sharing one instrument, alarm silenced routinely, or the switch coated | Fit an independent switch on another principle, alarm it separately, and test it as a safety function |
| Coating blistering at the liquid line | Wrong coating for the vapour phase, or condensation cycling at the interface | Specify the coating for both phases, and inspect the vapour space rather than only the wetted wall |
| Foundation settlement on one side | Ground conditions, poor drainage, or repeated hydrotest cycles | Survey the ring at fixed points on a schedule, fix the drainage, and involve a civil engineer before the shell distorts |
| Static discharge during filling | Splash filling, low conductivity product, or a container not bonded to the fill line | Fill from the bottom, keep the initial velocity low until the inlet is submerged, and bond and ground every container |
Go deeper: fluid storage news and case studies · frequently asked questions
Equipment Guide
Landia a/s
Landia is a worldwide supplier of Chopper Pumps and Mixer Solutions with its main businesses being wastewater anaerobic digestion/biogas agriculture and recycling of waste products.
Teledyne Gas & Flame Detection
For companies that demand the most reliable gas and flame detection solutions, Teledyne Gas and Flame Detection offers more than 100 years of proven experience in industries as diverse as oil gas, food beverage, marine and public utilities Always sensing safety, everywhere you look, Teledyne’s global portfolio of products and safety solutions are unquestionably first in class.
Ask the Expert
Engineers and product specialists who answer technical questions from readers. The answer comes back to you by e-mail; when we publish it, other readers benefit too.
Erik van den BoschTeledyne Gas & Flame Detection
A question on your Gas & Flame Detection needs ? Erik will guide you through the different solutions to protect your personnel… Ask a question
E-Product & Market Insights
Every Thursday, the E-Product & Market Insights edition takes one market or technology in depth. These are the editions on this zone — read them online or get the next one by e-mail.
Join 25,000+ engineers, plant managers and technical buyers. Free, twice a week.
Join 29000+ readers that receive our “web exclusive” articles, white papers, new products, and other information.
"*" indicates required fields
What this zone covers
When oxygen harms the product, when the vapour space would otherwise sit in the flammable range, or when breathing losses are worth money. A blanket needs a regulator, a relief and a check that the pressure stays in a narrow band: a few millibar too high and you vent nitrogen continuously, a few too low and air comes back in as soon as the tank cools.
The common rule is 110 % of the largest tank, or a quarter of the total volume, whichever is larger, plus an allowance for rainfall. The exact number is set by local regulation, so check it rather than assuming. The more useful question is what stops the liquid reaching the bund in the first place, because containment is the last defence, not the first.
Because a trip that shares the transmitter with the control loop shares every one of its failure modes: the same coating, the same lost echo, the same drifted zero. An independent switch on a different principle, alarmed separately and tested as a safety function, is cheap compared with a single overfill and it is what an assessment expects to find.
Fixed roof for products that do not evaporate expensively or dangerously, and it is the cheaper structure. A floating roof, external or internal, removes the vapour space and with it most of the breathing losses, which pays for itself quickly on volatile products and is often required by emission rules. The trade is the seal, which becomes a maintenance and inspection item for the life of the tank.
From the bottom, slowly at first. A low conductivity product falling through the vapour space builds static charge, and the tank is full of exactly the mixture that dislikes a spark. Keep the velocity below about a metre per second until the inlet is submerged, then raise it, and make sure every container and line in the transfer is bonded and grounded.
Bottom plate corrosion, water sitting under the product, coating breakdown at the liquid line, and foundation settlement. None of them shows up in the control room and all of them take years. Thickness readings, a settlement survey on fixed points and an internal inspection at the interval the standard sets are what turn them into planned work.
That depends on the product and the liner, not on the container. Plastic liners absorb and permeate, UV degrades them outdoors, and many products change specification long before the container does. Check the compatibility and the shelf life together, respect the stacking rating with the container full, and treat the couplings and grounding at the transfer point as the real risk.
The zone is the editorial side: news, case studies, videos, newsletter editions and field experts. The Equipment Guide is the directory side: equipment types and the manufacturers that build them. This page links to its Equipment Guide category and back.
Open the Equipment Guide category for this zone, pick an equipment type and open a manufacturer profile. Partner profiles carry direct contact details; other listings link to the company website.
Yes. Ask the Expert puts your question to a field expert in this zone. The answer comes back to you by e-mail; when we publish it, other readers benefit too.
