The direct synthesis of hydrogen peroxide is an attractive alternative for the traditional alkylanthroquinone process. To make this process economically feasible it is highly desirable to achieve total conversion of H2 and O2 without recycle, which means the H2/O2 in the feed should be at stoichiometric ratio. On the other hand, stoichiometric H2/O2 ratio is also a requirement of maintaining high catalyst selectivity. In addition, no dilutant should be used in order to maintain high H2 and O2 partial pressure and therefore to enhance reactor productivity. However, handling of hydrogen/oxygen mixture at 1:1 ratio without any dilution presents a significant safety concern, and achieving full conversion without compromising selectivity poses a big challenge for reactor design.

In this paper, we will present our experiences of using micro technology to meet such challenges. A mixer using micro technology was used to pre-mix hydrogen and oxygen before entering the catalyst bed. Both the micromixer and catalyst bed were designed to make sure the reactor can be operated safely for H2/O2 mixture in the explosion range as required to achieve optimal performance. Such concept was first tested in a small lab setup, and then a fully automated pilot plant was built to further demonstrate the reactor performance and to study the effect of various operation conditions.

The pilot plant data demonstrated the advantages of using micro technology for direct synthesis of hydrogen peroxide. Very high productivity with ~80% conversion and 75% selectivity has been demonstrated when using methanol as solvent. Based on pilot plant data, the scale up of this technology was proposed and the design of commercial reactor will be presented. Our experiences confirmed that when implemented properly the novel micro technology can be applied at large scale and become an enabler for a breakthrough new technology.