PTQ Q3 2023 Issue

Structured catalyst reactor system for steam methane reforming

Results from pilot plant test programme confirm significant advantages and value creation

Sanjiv Ratan and Bruce Boisture ZoneFlow Reactor Technologies LLC William Blasko and Wolfgang Spieker Honeywell UOP Florent Minette and Juray De Wilde Université Catholique de Louvain

S team methane reforming is the predominant and most widely used process for syngas and hydrogen produc- tion. The catalyst-induced reforming reaction is highly endothermic, thus calling for multiple tubes filled with cata - lyst and suspended in a furnace known in the industry as a steam methane reformer (SMR). The design, efficiency, tube life, and operational reliability of a SMR are governed to a large extent by its catalyst. Although a matured technology, it has seen only incremen- tal improvements in its catalyst design in conjunction with superior tube metallurgy over the years. The size and shape of current state-of-the-art pellet catalysts reflect the various developments aimed at improving heat transfer, pressure drop, and catalyst effectiveness. However, SMR performance with pellets catalyst remains inherently limited by heat trans- fer between the inner tube wall and the process gas, pore diffusion limitations, and heat transfer improvement at the cost of a higher pressure drop. ZoneFlow Reactor Technologies LLC (ZFRT) developed the proprietary ZoneFlow structured catalytic reactor system (hereafter called ‘ZF reactor’) for steam methane reforming as a technological advancement (see Figure 1 ). It has been shown to provide numerous benefits over conventional pel - let catalyst in terms of heat transfer, pressure drop, and cat- alyst effectiveness properties. 1,3 ZF reactor modules have an annular and structured flexible casing, designed to double heat transfer compared to pellets without increasing pressure drop.³ The development journey of ZF reactors included catalyst selection for coating based

on kinetic testing and modelling,² optimisation of the reactor design, and cost-effectiveness based on heat transfer-pres- sure drop testing,³ as well as computational fluid dynamics (CFD) modelling. 4,5 Past work and referred publications reported the results of detailed CFD modelling and comparative measurements of the pressure drop and heat transfer of commercial pellets vs ZF reactors. ZF reactors showed a heat transfer enhance- ment to the extent of 2.2-2.4 times that of the conventional pellet catalyst without any pressure drop increase at com- mercial flow regimes (mass flux of 9-12 kg/sec-m²).³ , 4 . 5 Subsequently, a rigorous pilot plant test programme for performance validation of the ZF reactors on near-com- mercial conditions was successfully conducted and com- pleted by November 2022 in a joint effort based on the Joint Development Agreement between Honeywell UOP and ZFRT (‘Pilot Plant Test Program’). Details and results of the pilot plant test programme are described further in this article. Table 1 summarises the main differentiators of ZF reactors over state-of-the-art pellets based on the results of the pilot plant test programme. Apart from the main advantages of enhanced heat transfer (2.2-2.4 times that of pellets with- out pressure drop penalty) and lower pressure drop (40- 50% lower vs pellets at the same flow rate), ZF reactors are stacked as modules in uniform loading in all the tubes. This results in uniform flow distribution over each tube compared to the randomly packed pellets causing inherent non-uni- formity of flow even with the best pellet loading methods.

Figure 1 ZoneFlow structured catalytic reactors to replace pellets in steam methane reforming. Left, conventional pellet SMR catalyst. Right, ZoneFlow reactor structured catalyst system

PTQ Q3 2023