Catalysis 2022 issue

This system allows for a liquid distribution error below 0.2% RSD, making it a highly accurate paral - lel liquid flow control device. Its auto-calibrating function enabled the use of a single flow sensor. Figure 6 illustrates the signifi - cance of controlling the flow to each reactor over time. Two modes are shown: capillary-equivalent mode, without active flow control, and the active mode, where the ALD is ena - bled to demonstrate the efficient liq - uid distribution. Note the difference in RSD from ±2% to less than ±0.25% for all 16 reactors, which improves the mass balance. A good feed distribution, gas, and liquid directly reflects in the accu - racy of the overall mass balance. For example, 1% deviation in feed is equal to 1% absolute deviation in mass balance across all reactors. Reactor pressure regulation Reactor pressure regulation is important to ensure accurate pres- sure control at operating pressures and help maintain equal distribution of the inlet flow over the 16 reactors. The Flowrence is equipped with a microfluidic-based reactor pres - sure controller (RPC). This pressure regulation technology allows one to individually regulate each separate reactor’s back pressure at the tar - geted set point, enabling the most accurate and stable pressure control in a multi-parallel reactors system, with an average reactor-to-reactor pressure deviation of <0.05 barg (<0.72 psig). Since the RPC measures the inlet pressure of each reactor, it can main - tain a constant inlet pressure by regulating the back pressure. As a result, the distribution of the inlet flows over the 16 reactors is unaf - fected, and a low reactor-to-reac - tor flow variability is achieved (see examples in the next section). In a set of measurements, accuracy is the closeness of the measurements to the actual (or reference) value, while precision is the closeness of the measurements to each other ( Figure 7 ). 6 In parallel reactor systems, pre - Data quality: precision and accuracy

Figure 5 Active Liquid Distribution (ALD) system (left) and individual liquid glass chip with temperature control (right)

No control

Active feed distribution mode












Time (min)

Figure 6 ALD control highlighting two modes of flow control to reactors: capillary equiv - alent mode, without active control of the flow, followed by active mode

must pass a strict quality control test to guarantee a channel-to-channel flow variability below 0.5% RSD. Active liquid distribution Total liquid flow is determined by a Coriolis mass flow meter. A fully automated active liquid distribu - tion (ALD) system ensures equal distribution over the 16 reactors for feeds such as naphtha, SRGO, LCO, VGO, HVGO, and DAO. The system continuously regulates the liquid flow to each reactor with real-time flow measurement to each reactor using a single flow sensor, with - out interrupting the flow to any of the 16 reactors. The system works with reactor pressure control (RPC) to ensure perfect flow distribution. Figure 6 shows a schematic drawing

of the 16 parallel reactors, the ALD, and a picture of the active microflu - idic glass chip.

Reference value




Figure 7 Accuracy is the proximity of measurement results to the actual value; precision is the degree to which repeated (or reproducible) measurements under unchanged conditions show the same results 6

56 Catalysis 2022

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