PTQ Q3 2023 Issue

monitors/detectors, also used for automated actions.

Apart from ensuring full compliance and accreditation with the various applicable tiers of codes and standards covering international, EU, and local regulations and stat- utory requirements, the pilot plant design and provisions underwent an exhaustive safety and operability review. This involved an external independent and accredited safety organisation conduct- ing an extensive Hazard & Operability (HAZOP) study and stringent layers of protec- tion analysis (LOPA) to match or even exceed the industrial safety standards. Test campaigns As part of the pilot plant test programme, four test cam- paigns, each extending over three to four weeks, were con- cluded successfully from July to October 2022. These safely covered near-commercial design and operating conditions in terms of space velocities, S/C ratios, temperatures, and heat fluxes (space velocity of 3,000-3,500/h, S/C of 2.5- 3.0, outlet temp of ~860ºC, avg. heat flux of ~75 kW/m2 ). One of the campaigns was carried out with state-of-the-art pellets for establishing the benchmark, and three with ZF reactors coated with different catalysts formulations from the leading steam reforming catalyst suppliers for compar- ative analysis. The natural gas flow rate varied up to 30 Nm³/h, and the furnace power was regulated to maintain the maximum tube skin temperatures within range. The operating pres- sure was set to 8 barg and the S/C ratio to 3. Some addi - tional tests at a lower S/C ratio of 2.5 were carried out with all ZF reactors to verify the resistance to coke formation of the different catalysts. The extensive operating data of all the test cases were continuously collected and stored as DCS/PLC parametric data, including detailed composition analysis of the pro- duced syngas (both dry and wet) using an online gas chro- matograph and mass spectrometer. The gas chromatograph analysis data were collected at minimised intervals based on the time needed for the analysis. The feed natural gas com- position was also analysed periodically to confirm its stability using another in-line GC-MS. The vast amount of collected data covering all flow rates, axial profiles of the tube skin, process gas temperatures, and dry and wet gas composi- tion were also used. This then helped to further develop and validate a simulation model for the prediction of commercial plant reactor performance and optimisation in conjunction with the SMR design. The analytical apparatuses were regularly and inde- pendently re-calibrated and had a good cross-check align- ment between the GC and the MS for desired accuracy and

Figure 3 The ZFRT pilot plant at UCLouvain, Belgium

section for other gases (N2 , Ar, H 2 ), water pretreatment, an electric steam boiler, an electrical SMR furnace for steam reforming, an outlet expansion interconnecting piece, a syn- gas steam generator, a steam superheater and flow and pressure control system, and back pressure regulation for flaring the generated syngas. The feed natural gas is drawn from the local low-pressure supply net. It is almost fully desulphurised in a two-layer cat- alytic adsorption reactor before compression in a compact multi-stage compressor. Other gases like N₂, Ar, and H₂ are fed from gas cylinder batteries. Boiler feed water is pre- treated (softener, RO unit, degassing, dosing) and fed to an electrical start-up/make-up boiler and to the syngas steam generator, which is used to cool the syngas exiting the reac- tor. The steam is superheated before being mixed under the imposed S/C-ratio control with natural gas and other gases. The reactor pressure is controlled through a back pressure regulator, and the pressure in the steam supply system through an independent back pressure regulator via which excess steam is vented. Mass flow controllers are used to control all flow rates. A syngas sample line for gas analysis is installed in the syngas exit line to the flare. The pilot plant is equipped with more than 300 instru - ments and I/Os, plus more than 120 valves and SPMs. Multiple thermocouples are employed to measure the tube skin temperatures and process gas temperature along the reformer tube length, with each temperature measurement de-doubled or tripled. The sulphur slip in the desulphurised natural gas is monitored online with a detection limit of 100 ppb. A few pictures of the pilot plant sections are shown in Figure 3 . The ZFRT pilot plant has been designed with special attention to safety requirements and health and environ- ment considerations, given its location within the university campus. The plant engineering also involved an extended cause-and-effect analysis and related DCS and PLC pro- gramming for various modes of operation and upset con- ditions. This was based on the operating philosophy/logic and related operating procedures covering start-up, normal operation, and routine and emergency shutdowns. The pilot plant is equipped with multiple observation cameras and gas

PTQ Q3 2023