Today, air gases and hydrogen are as natural a requirement for industrial processes as water and electricity.
On-site gas production facilities make sense wherever there is a constantly high demand for industrial gases. An on-site unit facilitates a cost-optimised and reliable supply, which is made even more secure through the use of backup systems and Messer logistics.
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.
AIR GASES PRODUCTION: NITROGEN AND OXYGEN
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. In addition to the two main components, nitrogen and oxygen, it is possible to obtain pure form argon as well as the rare noble gases krypton and xenon.
The cryogenic separation principle is used in the following Messer types of units:
• Multi-product high capacity air separation units with optional liquefaction
• CryoGAN nitrogen generators
• CryoGOX oxygen generators
- 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 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.
- Electrolysis, steam reformer or PSA – a question of the starting point
For smaller hydrogen consumers or customers who do not have an alternative source material on site, Messer offers electrolysis units for hydrogen production with a capacity of 0.5 to 100 Nm3/h. These units, individually designed by Messer, are modular in design, offering maximum flexibility when it comes to planning or expansion. Hydrogen purities of 99.9% and above can be achieved, thereby satisfying even the high purity standards of the food, electronics and chemical industries.
- Steam reformers
They 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 nickel based 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.
After this, the hydrogen-rich gas is cooled in several stages and condensate is separated. Finally, the hydrogen is purified in a multi-bed 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%).
The hydrogen PSA unit can be integrated into the customer’s existing setup and operates fully automatically, with the number of adsorption beds (tanks) depending on the H2 throughput.
The hydrogen product is available with constant flow, pressure and temperature values.
STEP BY STEP TO AN ON-SITE SUPPLY
Technical gas supply requirements essentially depend on the industry and applications in question. Against this background, Messer has developed a “priority ranking list” to facilitate project planning for an on-site supply in order to be able to offer supply concepts that precisely meet each customer’s requirements in terms of gas type, quantity and quality:
1. The customer’s technology process
2. Process parameters, including type of gas, pressure, purity, degree of automation, operating times, consumption profiles
3. Initial assessment/feasibility of project in terms of gas production technology, energy consumption, gas costs, backup facilities, safety considerations
4. Computer-based process modelling for simulation of technical concepts
5. Reliability analysis, ensuring efficient, uninterrupted operating times
6. Preparation and submission of tender for the supply concept
7. Completion/acceptance of supply concept
8. Installation and start-up of unit