Less oxygen,more safety and quality

Targeted protection duringproduction, storage and transportation,through inerting

Inerting offers safety in many areas where therisk of fire or explosion due to inflammable chem-icals, bulk materials and dusts exists. Further-more, inerting also offers protection from unwant-ed auto-oxidation or biological processes.During inertion, air and the oxygen it contains, isreplaced by an unreactive gas such as nitrogen,carbon dioxide or a noble gas.As one of the leading international industrial gascompanies, Messer has many years of know-how in the field of inertisation and is able tosupply the necessary gases.

No chance of explosions To eliminate the risk of explosion through inflam-mable dusts, gases or vapours, the atmosphericoxygen level is kept below the limiting oxygencontent (LOC). This prevents the creation ofexplosive mixtures. As the LOC varies from mate-rial to material, each inerting process has to beindividually designed.

Letting the air out of quality problemsMany oils and fats, particularly those from a vege-table source are prone to losses in qualitythrough auto-oxidation, polymerisation and fatdecomposition following contact with oxygen andmoisture. Storage of these products under aninert gas protects against losses in quality,increases the stability to oxidation and improvesproduct lifetime.

Increased safety via reduced oxygen content

The first biodiesel plant in Centraland Eastern Europe is in Trzebinia,

Poland. Since August 2005, nitrogenfrom Messer has been

maintaining the inert gas atmosphererequired for production and storage

of the fuel.

© Ruth R./Pixelio

© Maja Dumat/Pixelio

Permanent inertingClosed systems such as tanks or reactors areoften permanently inerted. In this case specialblanketing valves create a slight permanent over-pressure with inert gas in the tanks. Whendesigning the valves, pressure resistance,volume, location and existing insulation of thetanks has to be taken into account. In addition,the performance of the corresponding pumps forfilling and emptying of the tanks must also beobserved. In extreme situations, for examplelarge temperature variations during tankemptying, a peak in inert gas demand can occur.For such cases Messer provides sufficientvolumes and a reliable gas supply.The permanent existence of a slight overpressureprevents the entry of air and removes the needfor oxygen level monitoring.

On-demand inertingIn some open systems, such as dryers, inerting isonly required on demand. When the systemreaches an unsafe operating stage, for exampleStart Up or Shut Down, the oxygen level will bekept under the LOC through permanent purgingwith inert gas. With open systems, either perma-nent monitoring of oxygen concentrations ormaintenance of the required minimum inert gasflow is important to guarantee safe operation.

Inert gas lockTo prevent entry of atmospheric oxygen whenfilling vessels, special feeding devices are neces-sary. This is where inert gas locks are put intouse. For example, the counter current purging ofthe feed with inert gas will avoid the entrainmentof atmospheric oxygen. The inert atmosphere willremain in the system.

Inert gas locksprevent entrainmentof O2 during feeding.

Tank blanketing with N2

provides permanent safety.

© Ibefisch/Pixelio

© Angelika Lutz/Pixelio

          off gas

nitrogen

N2 storage vaporiser pressure control  tank/vessel/reactor

Inerting as fire-fightingSilos containing flammable bulk materials such ascoal, wood chips, cereals or dried sewage sludgeare often fitted with rapid inerting devices. Forthis reason the silos are equipped with CO- andtemperature-monitoring devices and an inert gassupply. If a smouldering spot is detected throughan increase in temperature or CO level, the siloheadspace is immediately inerted in order toavoid a dust explosion. At the same time, thematerial will also be inerted until the smoulderingfire is completely extinguished. Inertisation withN2 or CO2 prevents further damage to the pro-duct or silo, as would result through conventionalfire extinguishing methods.

Ideal explosion prevention and productprotection at a glance

Increased occupational health and safety•Protection of installations and products•Compliance with safety regulations•Lower insurance premiums•Maintenance of quality standards•Increased product availability•

In Lublin, Poland, dried sewage sludgeis stored safely in silos.

Possible fire or explosion risks canbe minimised using rapid inerting.

© Sarah C./Pixelio

© Angelika Lutz/Pixelio

  N2 storage vaporiser pressure control            silo

Which is the right inerting process for you? In order to find the optimal individual inerting pro-cess for you, the experts from Messer will carryout an extensive system analysis, taking intoaccount plant and material specifications.With initial or occasional inertisations, the appro-priate plant components are purged with an inertgas until the LOC is reached. Favourable plantlayout, such as wide apart entry and exit points,leads to lower inert gas requirements.To achieve a desired oxygen concentration, thenature and purity of the inert gas must be takeninto consideration. In most cases, nitrogen isused for inerting.

In one of the largest European bioethanolproduction plants in Pischelsdorf, Austria,nitrogen from Messer protects againstexplosions.

Foto: AGRANA Bioethanol GmbH

Theoretical amount of purge gas to reachrequired oxygen concentrations.

Finding the best solution togetherOur application engineers will be glad to adviseyou in choosing the right inerting method and inintegrating it into your process. For the safesupply of gases, whether as cylinders, cryogenictanks or on-site production, Messer is yourcompetent partner.

If you have any questions or require assistancefrom one of our applications experts, please donot hesitate to contact us.

Contact persons in your country can be found at:www.messergroup.com/de/Standorte/index.html

Messer delivers the correct gases in the correct way with the correct purity.

Messer Group GmbHGahlingspfad 31

47803 KrefeldTel. +49 2151 7811-0

Fax +49 2151 7811-501info@messergroup.com

www.messergroup.com