PTQ Q3 2023 Issue

100

Equal skin T

Reference pellets ZF-Catalyst-1 ZF-Catalyst-2 ZF-Catalyst - 3

Conventional pellet

Equal skin T

ZoneFlow

>15% throughput

Up to 35% throughput

100

110

120

% NG ow rate relative to max NG ow rate tested with pellets

Figure 4 Comparative performance of the ZoneFlow reactors with three different catalysts and of state-of-the-art pellets as observed in the pilot plant test campaigns

confirmation. Boiler feed water quality analysis was done at the RO unit exit, along with chemical dosing under make-up water control and continuous conductivity measurement in the syngas boiler. Results and conclusions The pilot plant test programme was aimed at:  Testing at equal capacity for lower methane slip at lower tube skin temperature than for the pellets reference case  Testing for at least a 15% increase in capacity compared to conventional pellets with no higher methane slip, maxi- mum tube skin temperature, or pressure drop. Appropriate repetitive testing was also included in the test programme. As shown in Figure 4 , all three ZF reactor campaigns conducted as part of the pilot plant test programme val- idated increased reforming capacity by at least 15% in terms of feed flow compared to the pellets, with no higher methane slip and without increasing the maximum tube skin temperature and pressure drop. For these campaigns, an additional test case at a lower S/C ratio (of 2.5 vs 3.0) was conducted to observe any susceptibility of the catalyst to carbon formation (or alternatively to ensure an adequate approach to C-equilibrium). No declines in performance – as measured by the % methane slip – were observed. The X-axis in Figure 4 shows the % NG flow rate rela- tive to the maximum NG flow rate tested with the pellets. It should be noted that the NG compressor could be operated at 115% of its rated capacity. The y-axis in Figure 4 shows the % methane slip relative to the maximum methane slip observed with the pellets as 5% vol dry at 100% relative NG flow rate. For the pellet reference condition and all three ZF reactors, the pilot plant test programme reported superior perfor- mance beyond the test target of a 15% increase in capacity at a lower methane slip and up to a 35% increase in capacity at the same methane slip with certain catalysts. The test results of the pilot plant test programme cam- paigns also supported the derivation of correlations for the ZF reactor interfacial mass and heat transfer coeffi- cients; that is, for mass/heat transfer between the process

gas and the catalyst surface. This allows a high level of confidence in establishing the simulation models for scal- ing up to any commercial SMRs and using those models to analyse the value creation in ZF reactor deployment to commercial SMRs. Importantly, the results of the testing campaigns allowed us to confirm several advantageous characteristics of ZF reactors that contribute to their improved performance vs conventional SMR pellet catalysts: • The heat transfer coefficient is increased to such an extent that the otherwise heat-transfer-limited steam reforming with pellets becomes instead catalyst-activity constrained • There is no bypassing of gas along the reactor tube wall, reflecting close contact of the ZF reactor with the tube wall • Catalyst coatings on the ZF reactor can provide more than sufficient intrinsic catalyst activity compared to state-of-the- art catalyst pellets • The ZF reactor structure promotes about a 5% radiative heat transfer contribution from tube wall to catalyst surfaces • The temperature curve from the tube wall to the inner por- tion of the reactor is flattened significantly. Value creation and NPV analysis Based on the verified results and findings of the pilot plant test programme,9 a detailed analysis of ZF reactor applica- tions was conducted with the following benefits assessment: ZF reactor retrofit in existing SMRs Considering the two modes of retrofit application, the fol- lowing are the main benefits:  SMR catalyst replacement • Overcoming capacity limitations from ‘stressed’ reformers • Energy (heat and power) savings • Prolonged tube life and enhanced reliability.  Capacity upgrading • 15% reforming capacity increase without increasing pressure drop, maximum tube skin temperature, and meth- ane slip • Related product capacity increase with only minor (case-specific) modifications

PTQ Q3 2023