Nicotinic Acid Synthesis At Elevated Beta-Picoline Load: Exploring The Possibility To Intensify The Process

The paper investigates the basics for increasing the productivity of gas-phase catalytic oxidation processes effected in multi-tubular reactors due to their operation at more concentrated feedstock. Obviously, an increase in initial concentration of the oxidizable reagent seems very attractive, but it is associated with the need to modify the process parameters and/or technological chart in order to achieve the required performance figures. This often entails excessive formation of by-products and therefore overheating of the catalyst bed due to increased heat generation. The cumulative effect of many factors can prevent attaining an acceptably high conversion of feedstock and the yield of target products within a reasonable size of a multi-tubular reactor. The problems we studied are quite typical for highly exothermic catalytic oxidation processes, but are not widely discussed in the literature. On the example of nicotinic acid (NA) synthesis in multi-tubular reactor, we investigated the advantages of the process with elevated feed load (beta-picoline), in comparison with the conventional conditions. On the basis of comprehensive process simulation supported by the experimental evidence, for the first time we have shown how the process should be operated to achieve a significant progress in the reactor performance and the target product yield. Our theoretical study showed that the rise in the initial beta-picoline concentration from similar to 0.8 to similar to 3% accompanied by a relevant adjusting of the process parameters leads to a dramatic 1.5-2-fold gain in the specific productivity of catalyst; this could greatly improve the reactor capacity. Optionally, a given production capacity of multi-tubular reactor may be ensured by similar to 2 times less number of tubes. Thus, the synthesis of NA at elevated initial feed of beta-picoline shall be significantly enhanced in comparison with the conventional process. (C) 2021 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.