cision is obtained when the same catalyst, tested at the same pro- cess conditions, yields the same results within a run (reactor-to-re- actor repeatability) or over multiple tests (run-to-run reproducibility). Accuracy is achieved when the results are translated directly into commercial performance. In a parallel system with mul- ti-reactors, guaranteeing the same conditions (P, T, flows and catalyst loading) in all reactors is crucial to obtain high-precision results. This section and the following examples demonstrate the high- est data precision. Moreover, we demonstrate the accuracy level with some examples comparing test results with larger reactors and a commercial unit for a semi-regen naphtha reforming unit. Pressure Precision of the pressure control (reactor-to-reactor) of ±0.05 barg (95% CI) can be achieved in ideal circumstances. There is always an impact of the type of application on this precision. Below are exam- ples for VGO hydrocracking and hydrotreating. In Figure 9 , we can see the accu- racy of the pressure control is excel- lent with a very narrow standard deviation for all 16 reactors, for both the inlet and outlet pressures This is crucial to maintain a good liquid distribution over the 16 reactors and the complete duration of the test. Mass balance Mass balance calculations ensure the metered flows used in the analyses are accurate. An accurate mass bal- ance is internal control of the data quality obtained. When calculating mass balance, various accurate measurements from both online and offline analyt - ical equipment are put together to determine mass balance accurately. Inherently, system errors from feed distribution to analytical measure- ments require some consideration in interpreting the reported data. The distribution of liquid (i.e., the LHSV) across each of the 16 reactors has a relatively significant impact on the recorded mass balance. In formula:
100.0±0.5wt% Most accurate mass balance closure
0.5%RSD Reactor-to-reactor uniformity
Active Liquid Distribution
Micro uidics Distribution
High precision (Flow, P, T)
Single-String Reactor Loading
Reactor Pressure Control
Reactor-in-Reactor Technology
Figure 8 High-throughput key technologies (see also Figure 1)
accurate mass balance, with all reac- tors between 98% and 102% and an overall average of 100.2 ± 0.6%. Reactor-to-reactor repeatability Another important quality crite- rion in parallelised reactors systems is reactor-to-reactor repeatability. Good repeatability is achieved when reactors loaded with the same cata- lyst system yield the same results. This means that the test results and the differences in catalytic perfor - mance measured in parallel reactors are reliable. The following examples illustrate
Mass balance (%) =[liquid sample collected + gas produced measured]/([total liquid feed+total gas feed]/16)×100 Mass balance closure precision and accuracy are key data qual- ity indicators. Figure 10 shows the excellent mass balance closure obtained for a VGO pretreat test with 16 parallel reactors. Similar mass balance precision and accuracy are obtained for hydrocracking tests. Figure 11 shows the mass balance for a test with eight hydrocracking catalysts loaded in duplicate reactors. There is very
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Mean: 147.300 barg Std. Dev.: 0.003 barg
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Mean: 147.204 barg Std. Dev.: 0.237 barg
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Figure 9 Example pressure control of 16 parallel reactors, 700 hours on stream (colours varied by reactor)
Catalysis 2022 57
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