Gas Purification: Solutions To Purify Gas To Your Requirements

Helium, argon, nitrogen, oxygen, carbon dioxide, syngas, hydrogen, natural gas, biogas and many more gasses are used one way or the other. All these gasses can find their applications in multiple industries, this can be for example in energy production for methane, natural gas and biogas, or in the case of helium, which can find its usage in exotic applications such as superconducting magnets.

The application in which the gas is used might require a certain purity level to have an efficient and cost-effective process. Think for example about biogas, if you do not purify the biogas before usage it might contain high moisture contents, high H2S concentration and a large number of siloxanes. All these impurities in biogas can cause damage to your engine during energy production. Another gas purification application can be H2S removal from CO2. You want to have pure CO2 in the production of beer, if you have H2S in the CO2 then your beer will have a terrible smell. There are many and many more gas purification applications, however to many to describe in a short blog.

There are lots of other components that can be removed from the various gasses by means of using a purification technology. Think about components as fungi, pollen, bacteria, viruses, mold spore elements, dust, acid gases and naturally occurring radioactive material (NORM).Do also think about organic (benzene, toluene, petrol vapors, VOC’s etc.) and inorganic molecules like carbon, soot, and all kind of minerals and metals(NOx, SOx, Hg, Pb, H2S, etc.). Some components that you want to remove might have a bad smell and some are bad for health and safety reasons and others might be needed to remove to get a very pure gas to run an efficient process.

Here is a list and short description of some of the key purification technologies used in gas purification;

1. Activated carbon

Activated carbon (activated coal, activated charcoal) is a special type of carbon that can adsorb various molecules from gas, and these are adsorbed in the large surface area by van der Waals forces. A gram of activated carbon has a surface that can be as large as a football field. This surface is divided into micro, meso and macro pores of the activated carbon. Activated carbon occurs in different particles size and different forms: powder, extrudates, granules and spheres. (press here to learn more about activated carbon)

2. Biofiltration

Biofiltration is often focused to remove smelly components from air by means of a biological active material in a filter. Components in the gas are then adsorbed by micro-organisms and are then oxidized by these micro-organisms into water, CO2 and salts. Various materials are used for biofiltration like for example peat.

3. Gas washing

Gas washing can work with both a wet and dry material. With this method the gas (or air) is brought into contact with the dry or wet material and the harmful components should then remain in for example the liquid phase. Various liquids can be used for this like for example amines, mea, dea, sulfuric acid, caustic soda and so on. (the opposing technique of this is aeration press here to learn more about aeration)

4. Filtration

In gas are sometimes particles that can range from bacteria to minerals and these can be removed with particle filters, which is actually a relatively simple process (selecting the right type is of course less simple). With particle removal from gas it is important that the filter has openings in the mesh screen that lets the gas through and captures the particles. Often these filters are made from stainless steel and have mesh screens that let the gas through and the particles not.

5. Ultraviolet

UV C disinfection is based on the absorption of UV C radiation by, for example, micro-organisms in gas. With the absorption of the UV-C, the DNA and RNA becomes damaged in the micro-organisms, so that the microorganisms can no longer reproduce. Just like with a normal lamp, the power is expressed in UV lamps in Watts (W). The more Watts the UV lamp has, the more power and effect for disinfection or sterilization this lamp will have. (press here to learn more about Ultraviolet)

6. Molecular sieves

 A molecular sieve is a solid material with a pore distribution that is very uniform and is used for adsorption in both the liquid and the gas phase. There are various types of molecular sieves such as carbon molecular sieves (CMS), zeolites, limestone and silica gels. With molecular sieving there is made a distinction between the types based on the micro (smaller than 2 nanometers), meso (between 2 and 50 nanometers) and macro pores (larger than 50 nanometers) they have.  (press here to learn more about molecular sieves)