A process for production of elemental sulfur from a feedstock gas including from 15% to 100 vol % H2S and a stream of sulfuric acid, the process including: a) providing a Claus reaction furnace feed stream substoichiometric oxygen with respect to the Claus reaction, b) directing to a reaction furnace zone operating at elevated temperature such as above 900 C., c) directing to a sulfuric acid evaporation zone downstream said reaction furnace zone, d) cooling to provide a cooled Claus converter feed gas, e) directing to contact a material catalytically active in the Claus reaction, f) withdrawing a Claus tail gas and elemental sulfur, g) directing to a Claus tail gas treatment plant, with the associated benefit of a process involving injection of sulfuric acid in a sulfuric acid evaporation zone allowing high temperature combustion of said feedstock gas, including impurities, without cooling from evaporation and decomposition of sulfuric acid.

The present invention relates to improving a performance of a production plant, in particular, in chemical industry. To this end, a method for determining a reactor performance for a catalytic reactor or reactor system is provided, the method comprising the steps of:providing reactor data indicative of a property of the catalytic reactor or the reactor system,providing catalyst configuration data indicative of a property of at least one catalyst present in the catalytic realtor or reactor system,providing a reactor model associated with the least one catalyst, the reactor model being configured for determining a catalytic reaction within the catalytic reactor or reactor system based on the reactor data and the catalyst configuration data,determining the reactor performance using the reactor data, the catalyst configuration data and the reactor model, andproviding the determined reactor performance for the provided catalyst configuration.

The invention relates to a method for manufacturing sulphuric acid, which involves converting sulphur dioxide SO.sub.2 into sulphur trioxide SO.sub.3, by injecting gaseous sulphur dioxide into a converter (1) inside which at least one mass (2) of a catalyst for the conversion is present, and according to which, during phases in which the injection of the gaseous sulphur dioxide is stopped, the space inside the converter (1) is heated in such a way as to maintain a minimum temperature of 200 C., and preferably 250 C., within each catalyst mass (2), characterized by the fact that the stopping of the injection of the sulphur dioxide is slaved to the starting of the heating, and vice versa.