Intelligent concepts for on-site gas production
Industrial gases: as important as water and electricity
There is a virtually unlimited supply of nitrogen, oxygen and argon because of their natural occurrence within the atmosphere. These gases, along with the rare noble gases present in air, can be obtained through special separation processes.
Every gas has its special “qualities”:
Today, air gases and hydrogen are as natural a requirement for industrial processes as water and electricity. Oxygen, for example, is used in steel refining, and is also essential in the glass industry as well as in environmental technology. The properties of nitrogen are used for inerting in chemical, petrochemical and pharmaceutical processes, among others. Argon, a noble gas obtained from air, plays a central role in the production of stainless steel and is also used as a purge gas in semiconductor manufacture.
Hydrogen is used in annealing high-alloy steels and sintered parts as well as oxide reduction of molten metal. It is also used as an efficient fuel in glass polishing.
Purity and quantity as required
On-site gas production facilities make sense wherever there is a constantly high demand for industrial gases. An on-site unit facilitates a costoptimised and reliable supply.
The volume and purity required varies from sector to sector and also depends on the process applications that are used. Messer therefore offers its customers a supply concept that is precisely tailored to individual requirements.
There are basically two air separation methods:
cryogenic and non-cryogenic.
Cryogenic air separation
In cryogenic air separation units, the gases present in the air are separated according to the low-temperature rectification principle, making use of the gases’ differing boiling temperatures.
The cryogenic separation principle is used in the following types of units:
• Multi-product high capacity air separation units with optional liquefaction
• CryoGAN nitrogen generators
• CryoGOX oxygen generators
|Constituent ||Chemical ||symbol % by volume |
|Nitrogen ||N2 ||78.08 |
|Oxygen ||O2 ||20.95 |
|Argon ||Ar ||0.93 |
|Carbon dioxide ||CO2 ||0.035 |
|Hydrogen ||H2 ||5 · 10-3 |
|Neon ||Ne ||1.82 · 10-3 |
|Helium ||He ||5.2 · 10-4 |
|Krypton ||Kr ||1.14 · 10-4 |
|Xenon ||Xe ||8.7 · 10-6 |
Non-cryogenic air separation
Non-cryogenic air separation processes work on the pressure swing adsorption principle or are based on separation by means of semipermeable membranes.
The following types of units are well established:
• Pressure swing adsorption (PSA)
• Vacuum pressure swing adsorption (VPSA)
• Membrane units
Messer offers air separation units, based on cryogenic and non-cryogenic separation processes, with the following nominal capacities:
|Type of unit ||Product ||Nm3/h ||t/day |
|Air separator ||O2 ||750 - 60,000+ ||25 - 2,000+ |
| ||N2, Ar ||up to 180,000 || |
|Generators ||O2 ||2,500 - 12,000 ||85 - 410 |
| ||N2 ||200 - 5,000 ||6 - 150 |
|PSA ||N2 ||10 - 5,000 ||0.3 - 150 |
|PSA / VPSA ||O2 ||100 - 5,000 ||3.4 - 170 |
|Membrane ||N2 ||10 - 3,500 ||0.3 – 105 |
Which type of unit is “best"?
It is necessary though to determine requirements in terms of gas purity, gas quantity and demand profile. An initial selection as to the appropriate type of unit can be made on the basis of the two diagrams below.
Cryogenic air separation units ensure a flexible and reliable supply
For industries that consume large quantities of oxygen, nitrogen and argon (steel, petrochemicals, refining), the gases are usually supplied via an air separation unit (ASU).
With this type of unit, air is first compressed to around 6 bar. After the removal of unwanted components – mainly carbon dioxide and humidity – in a molecular sieve, the air is passed into heat exchangers where it is cooled until it liquefies. This is followed by rectificatory separation into the individual components. A further option is the production of liquid products by means of additional cooling using expansion turbines.
Technology that meets your requirements
Messer offers a reliable and varied range of cryogenic air separation units, providing maximum flexibility from 25 to more than 2,000 metric tonnes per day (in terms of oxygen capacity).
Also available are liquefiers for a 100% liquid supply, which Messer builds with capacities of up to 600 metric tonnes a day.
CryoGAN nitrogen generators – a particularly cost-effective solution
Nitrogen (N2) is known for its protective qualities, which is why it is often used in inerting applications.
In order to meet the demand for larger quantities of nitrogen at low costs, Messer has developed the CryoGAN generator that operates on the principle of cryogenic air separation.
The units are modular in design and offer a graduated capacity range from 200 Nm3/h to 5,000 Nm3/h.
CryoGOX oxygen generators – compressed air and compressed costs
With CryoGOX oxygen generators, Messer has developed a cost-effective, reliable, flexible and uncomplicated oxygen supply. They are in demand from a variety of industries (pulp and paper, glass, ceramics, chemicals and metallurgy).
These generators, too, are based on the principle of cryogenic air separation. The stream of gaseous oxygen is available to customers at pressures of up to 20 bar. The main advantages of this concept are the high oxygen purity (99.6%) and the capability of cost-effective liquid nitrogen production for stockpiling.
CryoGOX oxygen generators are built by Messer according to customer specifications. Capacities from 85 to 400 metric tonnes a day cover most industrial applications.
How the customer benefits from cryogenic air separation
• High oxygen purity
• Very reliable operation
• Low energy consumption
• Parallel production of liquid oxygen and liquid nitrogen
Non-cryogenic air separation units for practically every requirement
PSA units – air is all you need
The PSA (Pressure Swing Adsorption) process is based on the physical adsorption properties of specially treated molecular sieves. PSA units only need clean, dry air in order to generate N2 or O2 cost-effectively and with purities of up to 99.9% (nitrogen) and 93% (oxygen). This air is compressed up to 10 bar, purified and then passed through vessels filled with the molecular sieve, either carbon molecular sieves (CMS) or zeolites, depending on the type of gas required (O2 or N2). While one vessel is in operation, the other is regenerated by reducing the pressure. The unwanted gas components are released into the atmosphere.
VPSA units – oxygen production can be this cost-effective
The VPSA (Vacuum Pressure Swing Adsorption) process represents a modification of the PSA process. VPSA units have a fan which generates an overpressure of around 1.5 bar, and a vacuum pump, which is used during the regeneration cycle.
Membrane units – nitrogen at the touch of a button
The membrane process makes use of the different rates at which air gases diffuse through a polymer membrane. Atmospheric air is filtered, compressed to the required pressure, dried and then passed through a membrane module. The air components with the higher rate of diffusion (O2 and CO2) penetrate the polymer membrane fibres more quickly, resulting in a nitrogen-rich flow as the primary product. The purity of the N2 gas flow reaching 93.0 - 99.5% and more if operated efficiently.
Reliable backup supply
A secure supply from a backup source – just in case it is ever needed – is the icing on the cake of any onsite concept, allowing the consumer to sleep easy with regard to the gas supply, even when there are maintenance downtimes, power cuts or other unforeseeable events. Every single customer receives a reliable supply of technical gases from Messer, even during planned and unplanned downtimes.
How the customer benefits from noncryogenic air separation
• Low costs – thanks to low energy consumption
• Reliability – selected components and regular maintenance are essential for reliable plant operations
• Nitrogen/oxygen as required – quick start-up and uncomplicated operation
• Modular units – transportable and low space requirement
Hydrogen production – as individual as its users
Messer offers a whole range of technologies for the production of hydrogen and Syngas, with the choice of the optimum process depending on several factors. These include the application, volume requirement and purity. The experts from Messer will be happy to advise you on this.
Steam reformers use natural gas as a feedstock and can be used for both small and large hydrogen units. With the so-called steam reforming process, the feedstock is mixed with process steam, heated to approximately 480°C and then split in the reformer using a nickelbased catalyst. In the CO Shift Reactor, in which carbon monoxide (CO) reacts with H2O to form H2 and CO2 (catalytic conversion), the hydrogen content in the reformed gas increases further.
Finally, the hydrogen is purified in a PSA unit. It leaves the PSA unit under 15 to 30 bar of pressure and with a purity of up to 99.9995%.
For companies that already have a hydrogen supply but require higher purities for downstream use, Messer can supply hydrogen PSA units as separate units. They receive the hydrogen-rich gas flow and convert it into high purity hydrogen (>99.999%).
Step by step to an on-site supply
Technical gas supply requirements essentially depend on the industry and applications in question. Messer has developed a “priority ranking list” to facilitate project planning for an on-site supply:
- The customer’s technology process
- Process parameters, including type of gas, pressure, purity, operating times, consumption profiles
- Initial assessment/feasibility of project in terms of gas production technology, energy consumption, gas costs, backup facilities, safety considerations
- Computer-based process modelling for simulation of technical concepts
- Reliability analysis, ensuring efficient, uninterrupted operating times
- Preparation and submission of tender for the supply concept
- Completion/acceptance of supply concept
- Installation and start-up of unit
Our aim is to develop a supply concept tailored to your individual needs
Messer’s aim in the area of on-site supply is clearly defined: on or next to the customer’s site, we operate units that are optimised to meet the particular gas requirements of each customer. This means that the customer can use the required gases just as easily as electricity from the grid. Such a supply is based on an appropriate supply contract for technical gases.
A strong background
Messer Group GmbH is one of the leading industrial gases companies in Europe and China. The company operates air separation units for bulk production and for supplying large industrial consumers from the steel, chemical and petrochemical industries. Liquid oxygen, nitrogen and argon are some of the products in greatest demand.
Messer has over 100 years of experience in the design and operation of air separation units and is constantly strengthening its lead in expertise.