WAO process addresses needs of refinery and petrochemical spent caustic treatment (photo: Siemens)
Based on experience and knowledge gained from application of the highly-effective Zimpro® wet air oxidation (WAO) technology, Siemens has developed an electro-oxidation process to address the needs of refinery and petrochemical spent caustic treatment. This new process – Zimpro® electro-oxidation – uses electrically conductive boron doped diamond (BDD) electrodes, enabling efficient oxidation of organic and inorganic compounds that are dissolved in spent caustic. The system’s flexible, modular design is capable of treating highly contaminated spent caustic streams typically generated by both refineries and petrochemical plants in producing clean fuels and chemicals. Treatment using Zimpro electro-oxidation produces an effluent that is amenable to traditional wastewater treatment processes.
The Zimpro electro-oxidation technology performs oxidation in a unique way, using electricity passed across BDD electrodes to produce oxidation reactions at near-ambient conditions. The oxidation potential is very high, allowing for polishing to end-of-pipe requirements in the wastewater plant. Unlike other advanced oxidation processes, no strong and expensive oxidising chemicals are required to be stored on- site, and the oxidation reactions only occur when electricity is applied to the electrodes.
The heart of the Zimpro electro-oxidation process is based on a reactor that contains high-purity, electrically-conductive, solid polycrystalline BDD electrodes. These specialised diamond electrodes generate hydroxyl radicals that, when combined with the chemically inert nature of the synthetic diamond, provide a long-lasting, efficient electrode for challenging oxidation applications like refinery and petrochemical spent caustics.
“We’re excited to bring this new technology to the market,” says Anthony Pink, CEO of Siemens Water Solutions. “Based on our experience and expertise in applying wet air oxidation to spent caustic treatment applications, the Zimpro electro-oxidation system will address a market that is currently served mostly by higher investment options or expensive external disposal options – those low-volume, highly-concentrated applications in which other types of treatment may be effective yet cost-prohibitive.”
Siemens Water Solutions addresses water and wastewater needs of the oil and gas industry with a portfolio that includes physical and chemical separation, biological treatment, and complex hydrothermal technologies. It brings decades of expertise and experience coupled with a technology portfolio and the ability to fully integrate the supply, from simple products to complete solutions, managing customer risk in execution and process performance.