The pre-reformer is an adiabatic catalytic reactor placed upstream the reformer in which the higher hydrocarbons contained in the natural gas feed are converted into methane thus preventing the formation of coke in the primary reformer feed preheat coil and at the catalyst tube inlet.
Increasing the overall plant reliability isn’t the only advantage of having a pre-reformer. The steam to carbon ratio can also be reduced, saving energy and allowing to increase the pre-heat temperature in the pre-reformed feed to the downstream reformer, which is beneficial in terms of reduced radiant duty and cost of the primary reformer. Additionally, the steam reforming reaction partially occurs in the pre-reformer and this further decreases the load of the primary reformer.
Casale's pre-reforming reactor features Casale’s well-proven, reliable axial-radial flow internals. With this kind arrangement, most of the gas passes through the catalyst bed in the radial direction, resulting in very low pressure drop. The balance passes down through a top layer of catalyst in an axial direction, thus eliminating the need for a complicated, gas sealed top cover on the catalyst basket.