Hydrogenation of 2-ethylanthraquinone is a key step in the industrial production of hydrogen peroxide via anthraquinone. This reaction on palladium-supported catalysts is normally carried out in trickle-bed reactors. A numerical model for simulation of a gas-liquid-solid hydrogenation trickle-bed reactor is presented. The model is based on the film theory and takes into account the axial dispersion effect on the performance of the reactor. Comparison of calculated values with data from pilot plant and industrial reactor shows that the agreement is quite satisfactory and the maximum variance is less than 5%. Gas-liquid and liquid-solid mass-transfer coefficients are determined by semi-empirical correlations available in the literature. The palladium-supported catalyst is extremely active and the reaction is always controlled by gas-liquid mass-transfer, and the overall effectiveness factor is always very low in agreement with the high catalytic activity of the palladium-supported catalyst.The overall effectiveness factor increases with decreasing catalyst hold-up. Therefore, it is feasible to improve the productivity of unit catalyst by decreasing the catalyst hold-up in a commercial plant with the hydrodynamic characters kept unchange.
The extraction process for preparing hydrogen peroxide with bottom air injection in a spray column was investigated With the increase of air superficial velocity, extraction efficiency was improved remarkably and the height of transfer unit (HTU) was largely reduced Extraction efficiency was 2-3 times higher than that of liquid liquid extraction without air introduction, and the HTU was only 1/2- 1/3 of liquid liquid extraction Moreover, the air liquid liquid reactive extraction system for preparing hydrogen peroxide via anthraquinone was investigated Oxidation reaction of the hydrogenated working solution was combined with extracting hydrogen peroxide from the working solution in a sieve plate column, which involves simultaneous oxidation of 2 ethylhydroanthraquionone and liquid liquid separation Oxygen was introduced with the hydrogenated working solution through a nozzle on the bottom of the column,with oxygen working as an agitating source as well as a reagent Reaction rate and extraction efficiency increased with increasing air injection superficial velocity because of great improvement of mass transfer between air liquid liquid
