Electrodialysis A low-energy, low-waste process for purifying chelates Wins for everyone Companies are keen to extract as much oil and natural gas as it possibly can from old wells. But often, natural gas extracted from older wells needs to be “scrubbed” to remove hydrogen sulfide and carbon dioxide. The most effective way to remove the sulfur compounds is with chemical compounds known as iron chelates (pronounced “key late”), and since 2003, AkzoNobel’s Functional Chemicals business has been providing two products to be used in gas sweetening: Dissolvine® H-50-GS and Dissolvine® H-FE-5.5-GS. Energy intensive Both products were produced in the Netherlands, which meant a 7000 km long supply chain, and a sizable carbon footprint. But beyond that, the production process used in the Netherlands – what is called an ion exchange process – was energy intensive and produced a significant waste stream of sodium nitrate. With those considerations in mind, a request went out to AkzoNobel’s Process Technology Expert Capability Group in the Netherlands to look into alternative separation and purification technologies. Bipolar Membrane Electrodialysis Before long, AkzoNobel scientists had come up with a promising candidate for an alternative production process to produce the chelates: Bipolar Membrane Electrodialysis (BMED). The beauty of BMED is that it is, in essence, a closed-loop process with virtually no waste. It also yields a much more concentrated solution which results in energy savings, because previously, energy was required to evaporate water to increase the concentration of the solution. The innovative technology underlying the BMED process draws on two crucial strengths within the Process Technology ECG – electrochemistry and membrane technology. And the end result is that since 2008 a BMED unit has been supplying both chemicals from a production site closer by resulting in a significant reduction in the carbon footprint. But it’s not just the environment or the customer that are winners: the innovation was recognized within AkzoNobel with the 2008 Sustainability award. Researchers have continued looking into the potential to use BMED in the production of other chemicals, which have important applications, contribute to the sustainability profile AkzoNobel is looking for and that create a mutually beneficial situation for both the customer and AkzoNobel. Want to know more?