Ammonia cracking units · Dissociated ammonia
Ammonia cracker manufacturer in India
An ammonia cracker splits ammonia over a nickel catalyst at 850 °C into dissociated ammonia gas, 75% hydrogen and 25% nitrogen, for bright annealing, sintering, brazing and float glass. Gastek, an Indian maker since 1993, has supplied them to steel companies in Egypt, Iran and North America, and its float glass units have run for over 15 years.
- Up to 200 Nm³/h of cracked gas from one unit
- Purifier to a −70 °C dew point, with the uncracked ammonia taken out
- Optional PSA purification for hydrogen up to 99.99%
- Gas
- 75% H₂ · 25% N₂
- Cracking
- 850 °C, nickel
- Capacity
- To 200 Nm³/h
Since 1993
Gas generation plants designed and built in India
Egypt · Iran · North America
Ammonia crackers supplied to steel companies
15+ years
Gastek crackers running on float glass lines
D-U-N-S 91-686-7372
ISO 9001:2015 quality management
What it is
What is an ammonia cracker?
An ammonia cracker, also called an ammonia cracking unit, dissociated ammonia generator or ammonia dissociator, makes a hydrogen-rich furnace atmosphere on site from liquid ammonia. Ammonia is 18% hydrogen by weight and stores easily as a liquid, so a few cylinders or a tank hold a great deal of hydrogen. Heated over a catalyst, it splits into its two gases.
2 NH₃ → N₂ + 3 H₂Ammonia to nitrogen and hydrogen. The gas doubles in volume, and the reaction takes in heat.
Dissociated ammonia, in figuresFrom the reaction
- Gas out
- 75% H₂, 25% N₂ by volume
- From 1 kg NH₃
- 2.63 Nm³ of cracked gas
- Hydrogen in it
- 1.97 Nm³, or 178 g
- Per Nm³ of gas
- 0.38 kg of ammonia
- Also called
- Ammonia cracking unit, ammonia dissociator, NH₃ cracker, cracked ammonia generator
How it works
How an ammonia cracker works
Five steps from liquid ammonia to dry furnace gas. Run the gas to follow it through.
Grey is ammonia, red is cracked gas. Purifier A dries while B regenerates, then they swap.
01
Ammonia in
Liquid ammonia from cylinders or a bulk tank is vaporised, and its pressure set.
02
Cracked at 850 °C
In the furnace it flows through a retort packed with nickel catalyst and splits: 2 NH₃ → N₂ + 3 H₂.
03
Cooled
The hot gas, now 75% hydrogen and 25% nitrogen, is cooled to near room temperature.
04
Dried and cleaned
Twin purifier beds take out moisture and uncracked ammonia, to a −70 °C dew point.
05
To the furnace
The gas is metered to the furnace, or sent on to PSA purification where pure hydrogen is needed.
Specifications
Ammonia cracker specifications
The gas Gastek's crackers deliver, and the plant that makes it. Each unit is sized to the furnace it feeds.
Ammonia cracker · specificationsGastek ammonia cracker brochure
The gas
- Output
- 75% H₂, 25% N₂ by volume: dissociated ammonia
- Capacity
- Up to 200 Nm³/h of cracked gas per unit
- Dew point
- Down to −70 °C with the purifier
- Residual NH₃
- Uncracked ammonia removed by the purifier
- Pressure
- Delivered to suit the furnace
- Pure hydrogen
- Up to 99.99% H₂ with PSA purification
The plant
- Process
- Catalytic cracking, 2 NH₃ → N₂ + 3 H₂
- Cracking
- 850 °C over nickel catalyst, in a heated retort
- Heating
- Electric; oil or gas fired on request
- Feed
- Liquid ammonia from a cylinder battery or a bulk tank, vaporised on the skid
- Purifier
- Twin beds: one dries while the other regenerates
- Controls
- PLC with alarms, interlocks and the instruments you specify
Ammonia use
How much ammonia does a cracker use?
One kilogram of ammonia gives 2.63 Nm³ of cracked gas: 1.97 Nm³ of hydrogen and 0.66 Nm³ of nitrogen. The table runs from a small furnace to the top of Gastek's range.
| Cracked gasNm³/h | HydrogenNm³/h | NitrogenNm³/h | Ammoniakg/h | Ammoniakg/day at 24 h | Ammoniat/month, 30 days |
|---|---|---|---|---|---|
| 10 | 7.5 | 2.5 | 3.8 | 91 | 2.7 |
| 25 | 18.8 | 6.3 | 9.5 | 228 | 6.8 |
| 50 | 37.5 | 12.5 | 19.0 | 456 | 13.7 |
| 100 | 75.0 | 25.0 | 38.0 | 912 | 27.4 |
| 150 | 112.5 | 37.5 | 57.0 | 1,368 | 41.0 |
| 200 | 150.0 | 50.0 | 76.0 | 1,824 | 54.7 |
Rule: Each Nm³/h of cracked gas takes 0.38 kg/h of ammonia. Theory at full cracking, at 0 °C and 1 atm; purifier regeneration and purges add a little. Above 200 Nm³/h, talk to Gastek.
Applications
Ammonia cracker applications
Where a furnace needs a reducing atmosphere, dissociated ammonia is the simplest hydrogen-rich gas to make on site.
Stainless steel wire, strip and tube
Bright annealing
A hydrogen-rich atmosphere keeps stainless steel bright as it anneals, with no oxide to pickle off. Hydrogen bell annealing in cold rolling mills uses the same gas, or pure hydrogen after PSA.
- Continuous and bell furnaces
- Bright finish without pickling
Powder metallurgy
Sintering and powder annealing
Cracked ammonia reduces the oxides on metal powders and sintered parts as they heat, so they bond cleanly.
- Metal powder annealing
- Sintered parts annealing
Brazing furnaces
Brazing
The reducing atmosphere lets the brazing alloy wet and flow on clean metal, in batch and conveyor furnaces.
- Brazing furnaces
- Bimetal products annealing
Steel processing lines
Galvanizing and strip lines
Hydrogen and nitrogen protect the strip in the annealing sections of galvanizing and processing lines. Gastek has supplied crackers to steel companies in Egypt, Iran and North America.
- Continuous galvanizing lines
- Strip annealing
Float glass tin bath
Float glass
Hydrogen in the tin bath atmosphere stops the molten tin oxidising under the glass. Gastek's crackers have run on float glass lines for over 15 years.
- Tin bath atmosphere
- Continuous duty
Oils and pharmaceuticals
Hydrogenation and reduction
With PSA purification, cracked ammonia becomes a hydrogen supply for hydrogenating castor and other non-edible oils, and for reduction steps in bulk drug plants.
- Castor oil hydrogenation
- Bulk drug reduction
PSA hydrogen purification
Hydrogen from ammonia: cracker and PSA purification
When a process needs hydrogen rather than the 75/25 mix, a PSA unit after the cracker takes out the nitrogen. Together they make a complete hydrogen plant that runs on ammonia.
Cracked gas, used directly
75% H₂ · 25% N₂ · −70 °C
- Bright annealing and heat treatment
- Sintering and brazing
- Galvanizing lines and float glass
Purified hydrogen
H₂ up to 99.99%
- Hydrogen bell annealing
- Hydrogenation of castor and non-edible oils
- Reduction in bulk drug plants
Choosing a route
Ammonia cracker, electrolyser or HNx?
Four ways to a hydrogen atmosphere, all made by Gastek. The gas your furnace needs decides between them.
| Route | Gas | Made from | Electricity | On site | Suits |
|---|---|---|---|---|---|
| Ammonia crackerThis page | 75% H₂, 25% N₂ | Liquid ammonia and heat | Heat for an 850 °C furnace | Ammonia storage and handling | Bright annealing, sintering, brazing, galvanizing, float glass |
| Cracker with PSA | H₂ up to 99.99% | Liquid ammonia and heat | The cracker's, plus the PSA | Ammonia storage and handling | Hydrogen bell annealing, hydrogenation, bulk drug reduction |
| Electrolyser | H₂ up to 99.999% | Water and electricity | The most per Nm³ of hydrogen | No ammonia; treated water | Pure hydrogen where ammonia isn't wanted |
| HNx blending | N₂ with 2–10% H₂ | Nitrogen and hydrogen | Mostly the nitrogen plant's | A nitrogen plant and a hydrogen supply | Protective atmospheres with little hydrogen |
Safety
Ammonia cracker safety
Ammonia and hydrogen both need care. Gastek plans the package around the site as well as the furnace.
Built into the plant
- Ammonia leak detection, and a ventilation review
- Hydrogen detection, safe venting and pressure relief
- Purge, start-up and shutdown sequences
- Emergency shutdown and interlocks
Planned with you
- Site layout, cylinder or tank handling, and access for maintenance
- Operator training and commissioning checks
Export
Ammonia crackers for export
Gastek has supplied ammonia crackers to steel companies in Egypt, Iran and North America, built in India and shipped to site.
Middle East
- UAE
- Saudi Arabia
- Qatar
- Oman
- Kuwait
- Bahrain
Crackers for steel, heat treatment, glass and protective atmospheres, with Gulf site conditions in the design.
Ammonia crackers for the Middle EastElsewhere
Send the site, the furnace and the gas demand. Gastek quotes with documents, packing and start-up planned for the country.
Request quoteAmmonia cracker FAQ
Ammonia cracker questions
What is an ammonia cracker?
An ammonia cracker, also called an ammonia cracking unit, dissociated ammonia generator or ammonia dissociator, heats ammonia over a nickel catalyst at about 850 °C so that it splits into hydrogen and nitrogen. The gas that comes out, dissociated ammonia, is 75% hydrogen and 25% nitrogen by volume, and is used as a reducing atmosphere in heat treatment furnaces.
How does an ammonia cracker work?
Liquid ammonia is vaporised and fed into a retort packed with nickel catalyst inside an 850 °C furnace, where it splits by the reaction 2 NH₃ → N₂ + 3 H₂. The hot gas is cooled, then a twin-bed purifier takes out moisture and uncracked ammonia, to a −70 °C dew point, before the gas goes to the furnace.
Is an ammonia cracker the same as a pure hydrogen generator?
No. The direct output from an ammonia cracker is H₂/N₂ cracked ammonia gas. It is useful for many protective and reducing atmosphere applications. If the process needs high-purity hydrogen, a downstream purification package such as PSA hydrogen purification can be added.
How much ammonia does an ammonia cracker use?
One kilogram of ammonia gives about 2.63 Nm³ of cracked gas, of which 1.97 Nm³ is hydrogen. A furnace taking 50 Nm³/h of dissociated ammonia therefore needs about 19 kg of ammonia an hour, or 456 kg a day at 24 hours. Purifier regeneration and purges add a little.
What dew point and purity does cracked ammonia gas have?
Straight from the furnace it is 75% hydrogen and 25% nitrogen, with some moisture and a trace of uncracked ammonia. Gastek's purifier dries it to a dew point as low as −70 °C and takes out the uncracked ammonia. Specify the flow, outlet pressure, dew point, residual ammonia, operating hours and duty cycle your furnace needs.
Which industries use ammonia cracking units?
Common industrial uses include heat treatment, bright annealing, brazing, sintering, metallurgy, steel processing, float glass, specialty glass, HNx or protective atmosphere systems, and selected hydrogen-rich process gas applications.
Can cracked ammonia gas be purified to hydrogen?
Yes. Cracked ammonia gas can be the feed to a hydrogen purification package when the use point needs higher hydrogen purity. The final package depends on hydrogen flow, purity target, impurity limits, pressure and recovery. Gastek's PSA purification gives hydrogen up to 99.99%.
Ammonia cracker or electrolyser: which is better?
It depends on the gas and the site. A cracker makes a hydrogen-rich gas from ammonia with far less electricity per cubic metre of hydrogen, and suits furnaces that use the 75/25 mix. An electrolyser makes pure hydrogen from water and power, with no ammonia on site. Gastek builds both, so it can compare them on your flow, purity and power cost.
What does an ammonia cracker cost?
The price depends on capacity, how the furnace is heated, whether a purifier or PSA hydrogen stage is included, the level of automation, and installation and commissioning. The running cost is mostly ammonia and heating power, so ask for the cost per Nm³ of gas as well as the price of the plant. Gastek quotes from your flow, gas quality and site.
What maintenance does an ammonia cracker need?
Gastek's brochure calls its crackers virtually maintenance-free. The parts that age are the catalyst, the furnace retort and the purifier's adsorbent, which are checked at service visits and replaced when worn. Leak detectors and safety interlocks are tested on a schedule.
What safety items matter for ammonia crackers?
The design discussion should include ammonia handling, hydrogen safety, leak detection, ventilation, purge logic, emergency shutdown, pressure relief, safe venting, instrumentation, site layout, commissioning and operator training.
What information does Gastek need to size an ammonia cracker?
Useful inputs include the application, cracked gas or hydrogen flow, pressure, dew point, residual ammonia target, purity requirement, operating schedule, ammonia source, site utilities, safety constraints and installation location.
Next step
Send your furnace's gas demand. Get a cracker sized to it.
Share what you know. Gastek replies with the size, the gas quality it will deliver, and what the site needs for ammonia.
Gastek contact hoursMon–Sat, 9:00 am–6:00 pm IST
- Furnace type and the gas flow it takes, in Nm³/h
- Dew point and residual ammonia it needs
- Hours a day, and the peak demand
- Ammonia supply: cylinders or a bulk tank
- Site and country