Full Liquid Air Separation Unit for LOX, LIN and LAR Output

What "Full Liquid" Actually Means

A conventional gaseous ASU pushes product out a pipe. A full-liquid ASU condenses its entire output - or all but a whisper of gas for its own needs - and hands it to the world as pumpable, haulable liquid. No pipeline customer, no offtake handshake needed: the products go into vacuum-insulated tankers and travel to whoever needs them that week. For a merchant gas business, that flexibility is the difference between a supplier and a hostage of one pipeline neighbor.

Internally, the difference is refrigeration architecture. Without warm product gas returning to exchange cold, the plant generates its own refrigeration in cycles - and which cycle you pick drives efficiency, cost and how the plant behaves on a Tuesday at 2 a.m. during demand turndown.

The Cycle Family

• Low-pressure nitrogen cycle - the classic workhorse. Nitrogen is compressed, chilled, expanded to make cold. Simple, robust, forgiving.
• LP cycle with cryogenic chiller - adds a subcooler loop that trims exergy losses; modest capital for a real energy pull.
• Medium-pressure cycle - tighter exchangers, higher pressures, smaller cold boxes; favored where site space is expensive.
• Medium-pressure dual expansion - two expander stages recover more work; the energy-efficiency pick for continuous-duty merchant plants.

We pick the cycle against your tonnage, electricity price and product mix - a 300 TPD plant on a premium tariff in a hot climate is a different animal from a 1,000 TPD plant on cheap power at temperate latitude. All four cycle designs come from the same in-house process team, simulated per site.

Representative Configuration (KDONAr-3000Y/4000Y)

Argon tie-ins, product pressure packages and storage/fill stations are all designed against your market's pull pattern. The YDS dewar fleet, CFL tank farm and welded-insulated cylinder pack at the battery limit come from the same factory, which keeps fill headers, venting and custody transfer simple.

The Merchant Arithmetic

Ask the question any investor asks: on-site production cost per ton versus wholesale liquid price in your territory, minus freight. In most developing gas markets the spread funds the plant in three to six years and then prints margin behind it. Our gas-investment desk goes further for qualified partners - see the gas plant investment page - because we'd rather co-invest in a plant we built than compete with someone else's cheap unit across your fence.

Build Quality Is the Boring Part That Matters

Cold boxes as large pre-piped blocks welded under A1/A2 pressure-vessel licenses and pressure-tested before shipping. Multi-layer main exchangers from our own process design. DCS sequences with proven startup paths - first liquid on a defined day of commissioning, not "whenever." The reference count behind these statements is nearly 300 delivered ASU projects across 20+ countries, including full-liquid trains in Turkey and Indonesia running merchant duties.

FAQ

Who Actually Buys A Full-Liquid Plant

A full-liquid ASU is the machine you run when your product leaves the site in tanks, not in pipelines. Three buyer profiles fill most of our order book in this family:

• Independent gas companies. The classic customer. A 3000Y or 4000Y full-liquid plant feeds a fleet of cryogenic tankers serving welding shops, hospitals and food plants across a few hundred kilometres. The business model is logistics margin, so the plant is sized to fill trucks around the clock, with liquid reserve for surge weeks. These owners care about one number: cost per tonne of liquid delivered.
• Steel and petrochemical sites with liquid peaking duty. Pipeline gas covers the base load from a gaseous ASU; the full-liquid unit covers winter peaks, shutdown cover, and sells the surplus into the regional market. Running one plant for both duties beats buying standby liquid at spot prices.
• Aerospace and special-program supply chains. High-purity liquid for rocket propellant and test facilities - where product purity documentation matters as much as tonnage and our quality records packages earn their keep.

The Cycle Choice, Explained Without The Textbook

Full-liquid plants differ from gaseous plants in one fundamental way: everything that can condense, condenses. No product gas leaves the cold box warm; you pump and vaporize liquids downstream instead. That inverts the energy economics and makes the compression cycle the central decision:

• Low-pressure single cycle. One air compressor, expanders make the refrigeration, simplicity is the selling point. CAPEX-light, robust, tolerant of operators still learning the plant. Our entry answer for independent gas companies at small and mid capacity.
• Low-pressure double cycle. A nitrogen recirculation loop shares the refrigeration load with the expander. Better specific energy at scale; a bit more complexity in the controls and the nitrogen compressor. Where we steer growing gas companies planning their second and third plants.
• Medium-pressure double expansion. For larger full-liquid plants where the air compressor runs comfortably at medium pressure and two expander stages make cryogenic sense. Higher efficiency, tighter engineering margins - the flow our process people discuss longest on every quotation.

We pick the cycle from your capacity, tariff and operating maturity - not from what is easiest to build. A first-time owner gets the single cycle even when the double cycle looks prettier on the energy estimate, because a plant your team can run beats a plant that needs our engineer on site forever.

From Steel To First Liquid: The Delivery Sequence

A KDONAr-Y plant ships as modules: air compression, purification house, cold box, expansion skid, liquid storage (from our own CFL tank line) and the filling station. Site work is foundations, utility ties and module setting. Cold commissioning follows a written sequence - dry, cool, accumulate liquid, adjust, then the performance run against contract curves for output, purity and specific energy.

Plan realistically on schedule: engineering to first liquid for a 3,000-4,000 class plant runs in months, not years, when your civil works keep pace with our module deliveries. Owners who involve us at site-selection stage consistently hit their dates; owners who order the plant then design the site around it consistently do not. Your twelve-month liquid revenue starts on the day the first tanker loads - everything in the sequence above is scheduled backwards from that truck.