Company file

INOX Air Products

Published 3 August 2026. Facts verified to 27 July 2026 unless dated otherwise.

INOX Air Products has a reported Rs 500 crore electronic specialty gas hub and 200 TPD air separation unit at Dholera to supply ultra-high-purity gases to the fab ecosystem.

Status tier: REPORTED

Why a gas plant is the tell

Announcement-stage cities attract billboards. Construction-stage cities attract process suppliers, because nobody erects an air separation unit for a customer that does not exist. Ultra-high-purity nitrogen, oxygen and specialty gases are non-negotiable fab inputs, needed continuously and locally. A reported cold box already standing is one of the more concrete physical signals in the REPORTED tier of the ledger.

The stated customer set spans the Tata fab ecosystem and ReNew's referenced cell facility, which is exactly how industrial clusters form: one anchor, then the suppliers, then the suppliers' suppliers. The supply chain briefing maps the rest.

The contract that sits behind the cold box

Industrial gas is one of the few industries in which the supplier builds a factory inside the customer's fence and sells the output back through a pipe a few hundred metres long. An on-site plant is project finance in industrial clothing: the gas company funds and owns the air separation unit, the consumer signs a long tenure supply agreement, and the price typically splits into a fixed monthly facility charge that recovers the capital and a variable charge indexed to electricity. That model is the one that carries evidential weight, because nobody underwrites fifteen years of plant depreciation against a customer who might not exist.

Civil works get started on political timelines. A cold box gets started on a credit committee's. INOX Air Products is reported to have begun construction in October 2025 of an electronic specialty gas hub at Dholera at around Rs 500 crore, with a 200 tonnes per day air separation unit REPORTED. What has not been published is the thing an analyst would most want: no supply agreement between INOX Air Products and Tata Electronics is in the public domain, and neither tenure, volume commitment, take-or-pay floor nor indexation has been disclosed. A hub built against a signed anchor contract and a hub built to position for a cluster that has not yet contracted are the same steel and very different risk.

What an air separation unit actually does

Dry air is roughly 78 per cent nitrogen, 21 per cent oxygen and 0.93 per cent argon by volume. Separating it at scale is done by cryogenic distillation, the same principle as any distillation column but run hundreds of degrees colder. Air is filtered, compressed to a few bar, cooled, then passed through molecular sieve adsorber beds that strip out water vapour, carbon dioxide and hydrocarbons. That step is not optional housekeeping: water and carbon dioxide freeze solid at cryogenic temperatures and would plug the heat exchanger, so the beds run in pairs, one adsorbing while the other regenerates on warm waste nitrogen.

The clean air then enters the main heat exchanger, a brazed aluminium plate-fin block that cools the incoming stream against the returning cold products. A turboexpander extracts work from part of the flow, and that is what actually produces the plant's refrigeration. By the time air reaches the columns it is close to minus 175 degrees Celsius and partly liquid. Separation happens in a double column, a high pressure and a low pressure column linked thermally by a condenser-reboiler, so the nitrogen condensing at the top of one boils the oxygen at the bottom of the other. Nitrogen, boiling at about minus 196 degrees, leaves overhead and oxygen, at about minus 183, collects in the sump. Argon sits inconveniently between them at about minus 186, so it is drawn as a side stream into a crude argon column and purified separately, which is part of why argon is typically the scarcest and dearest of the three.

All that cold equipment sits inside the cold box, a tall steel casing packed with perlite insulation, which is why its erection reads as a milestone. It is also why such plants are not casually switched off: cooling a column train from ambient takes many hours, and an unplanned trip means a warm-up, a de-rime and a restart before product is back on grade.

Commercially, the whole assembly is best understood as a very large electric motor that yields gas as a by-product of compression. Power is typically the largest single line in the cost of pipeline nitrogen, which is why the price and reliability of electricity weigh as heavily on where these plants are viable as the proximity to the customer that the product's transport economics already dictate. On the power side Dholera has some documented support: of the 1,000 MW solar park, the 300 MW awarded to Tata Power Solar is commissioned DURABLE, the remaining 700 MW is under development against a March 2027 target TARGET, and the Gujarat Semiconductor Policy 2022-27 carries a power subsidy of Rs 2 per unit for ten years plus electricity duty exemption DURABLE. Whether a gas supplier qualifies for that semiconductor-linked support or buys at ordinary industrial tariff is not published, and over a fifteen year contract the gap between those tariffs can outweigh the difference between competing plant designs.

Why nitrogen is the gas a fab drinks

Nitrogen is rarely a reactant. It is the atmosphere the process lives inside, which is why it dominates fab gas consumption by mass by a wide margin. It purges load locks between vacuum and ambient, blankets wafer carriers so that a surface prepared in one tool does not grow an oxide before it reaches the next, flows continuously through tool enclosures and mini-environments, and dries wafers after wet cleaning so that water does not leave a stain that becomes a defect. It serves as a dilution and carrier gas in deposition, and it purges the delivery lines before and after every hazardous gas is used, a safety duty rather than a process one.

The consequence for a supplier is that nitrogen demand tracks installed tool count and cleanroom volume more closely than it tracks wafer output. A fab in a slow ramp still draws close to its full nitrogen load, because purge does not stop when production pauses. That is convenient for the gas company and painful for the fab, and it is one reason the fixed and variable split in these contracts is negotiated so hard.

Purity is the other half. Nitrogen at the tool is specified in parts per billion of oxygen, moisture and hydrocarbons, not parts per million, and at that level purity is a delivered property rather than a produced one. The distribution system determines as much of it as the column does: electropolished stainless steel, orbital welded joints rather than threaded ones, face-seal fittings, continuous positive pressure so any leak leaks outward, and point-of-use purifiers. A plant can make excellent nitrogen and a badly built line can ruin it in two hundred metres.

What 200 tonnes a day actually buys

The reported figure of 200 TPD REPORTED deserves unpacking, because tonnes per day is a plant-scale unit and a fab thinks in flow. Two hundred tonnes a day is about 8.3 tonnes an hour. Nitrogen at normal conditions has a density of roughly 1.25 kilograms per normal cubic metre, so a tonne is about 800 normal cubic metres, and an all-nitrogen output would be roughly 160,000 normal cubic metres a day, or about 6,700 an hour.

It will not all be nitrogen. The reporting names nitrogen, oxygen and argon plus specialty gases REPORTED, but no breakdown between those streams has been disclosed, nor any split between gas piped over the fence and liquid routed to storage. Liquid capacity is what gives a site its ride-through: a cryogenic vessel and vaporiser bank keep a fab's purge flowing through a plant trip or a grid event, and that buffer's sizing has not been stated publicly.

For scale, very large 300mm fabs are generally served by nitrogen supply measured in tens of thousands of normal cubic metres an hour, and industry practice is to add capacity in trains rather than build the final number on day one. A reasonable reading of 200 TPD, and it is a reading rather than a reported fact, is a first-phase plant sized for early ramp plus ecosystem demand, with expansion assumed. The Tata fab is guided to commercial production in mid-2028 TARGET and no first silicon has been reported as of 4 August 2026 DURABLE. A plant sized today for the fab's mature draw would spend years idle.

Pipeline, tanker and cylinder are three different businesses

Over-the-fence pipeline supply has the lowest unit cost and the least flexibility, since the asset is captive to one customer and its economics collapse if that customer stops drawing. Merchant liquid supply is a trucking business with cryogenics attached: vacuum-insulated tankers deliver into on-site vessels, product boils off slowly in transit and storage, and distance is therefore a direct cost. Liquid nitrogen becomes uneconomic beyond a few hundred kilometres, which is the main reason a fab wants its gas made locally.

Cylinder supply is a different animal. Per unit of gas it is by far the most expensive route and the only sensible one for specialty gases consumed in kilograms rather than tonnes. The cylinder itself is the business: a returnable pressure vessel that must be tracked, hydrostatically requalified on a schedule, fitted with the correct valve outlet, passivated internally for corrosive service and segregated by hazard class. Much of what an electronic specialty gas hub does anywhere in the world is filling, blending to specification, analysis, repackaging and storage of bought-in product, rather than synthesis from feedstock. Which of those functions the Dholera hub will perform has not been specified in the reporting available REPORTED, and the gap between a filling and distribution centre and a manufacturing site is the gap between a warehouse with analytics and a chemical plant.

The hazardous half of the gas list

Bulk gases are boring by design. Specialty gases are not. Silane, used for silicon deposition, is pyrophoric and ignites on contact with air. Ammonia, consumed in quantity in nitride work, is toxic and corrosive. Hydrogen chloride and chlorine are corrosive etchants, and the dopant hydrides arsine, phosphine and diborane are acutely toxic at a few parts per million or less. Fluorinated species such as nitrogen trifluoride and sulphur hexafluoride, used for chamber cleaning and etching, carry global warming potentials thousands of times that of carbon dioxide and atmospheric lifetimes measured in centuries to millennia.

Handling them is a discipline of layered containment rather than of care. Cylinders sit in ventilated gas cabinets with automatic isolation and excess flow protection, and distribution runs through valve manifold boxes and, for the worst gases, coaxial double-containment tubing whose annulus is monitored so a leak is caught before it reaches a room. Cross-purge assemblies clear the line with inert gas before any cylinder change, toxic gas monitoring covers cabinet, line and tool with remote shutoff, and storage is bunkered and segregated by hazard class.

Downstream, point-of-use abatement burns, plasma-cracks or scrubs the exhaust before it reaches the house system, and the destruction efficiency of that equipment shapes a fab's direct, on-site greenhouse footprint, of which fluorinated process gases rather than on-site fuel use are typically the largest part. Abatement is also a recurring service business: fuel gas, scrubber media, water treatment and periodic efficiency testing. No abatement, storage or district emergency-response arrangement for Dholera has been published, and since hydride storage is one of the things that sets an industrial site's off-site consequence distance, that is a real gap rather than a detail.

Qualification is the slow part

A fab does not buy gas, it qualifies it. Each gas, at each purity grade, for each tool family, has to pass an analytical and process qualification: trace moisture by cavity ring-down spectroscopy, trace oxygen by laser or electrochemical analysers, hydrocarbons by flame ionisation, particle counting on the delivered stream, certificates of analysis per batch, then formal change control before the material touches production wafers. That work runs for months, in parallel with tool installation rather than after it. It is the quiet reason an on-site gas plant must be finished and stable well before first silicon.

The coupling cuts both ways. Main fab foundations were reported in November 2025 to require redesign after soil testing, with Fugro, Cengrs and Geo Dynamics engaged REPORTED, and cleanroom design and installation was reported onboarded to Malaysia-based IAQ Group in June 2026 REPORTED. Those two items govern when tools arrive and therefore when gas qualification can begin, and a supplier that has already committed capital carries the cost of waiting unless its contract says otherwise.

The service economy a gas hub leaves behind

An air separation unit is not, by itself, an employer of consequence: it is a continuous process plant run largely from a control room by a modest shift of operators and instrument technicians plus a maintenance team. The employment that matters sits around it. Cryogenic road transport needs drivers with hazardous goods endorsements and tankers with a maintained vacuum jacket. Cylinder operations need filling, testing, valve service and statutory pressure-vessel requalification. High-purity distribution needs orbital welders and clean pipe fitters, a certified trade that any new semiconductor region either imports at cost or trains deliberately. Then come the calibration and analyser labs, third-party inspection agencies, safety trainers and the hazmat response capability a district needs once hydrides are stored inside it.

The structural point is that the second customer to arrive does not pay for the air separation unit. Once a gas producer is established, the marginal cost of serving the next process plant nearby falls sharply, which is the ordinary mechanism by which industrial clusters compound. Dholera has a candidate second customer on the record: the Union Cabinet approved Crystal Matrix Limited's integrated compound semiconductor unit at Dholera on 5 May 2026 DURABLE, and compound work draws a heavier gas basket, with the large ammonia and hydrogen volumes typical of gallium nitride epitaxy. Linde has separately been reported, at low confidence and from trade press only, to be advancing plans for a Dholera plant REPORTED. If that report holds, two suppliers chasing one anchor is a very different picture from one supplier with a signed contract, and the announcements published so far do not settle which of those Dholera is. The supply chain briefing tracks the rest of the input layer.