What is the core principle of feedforward control, and how is it applied in a hydrogen production plant?

The core principle of feedforward control is to anticipate the effect of disturbances on a process and take corrective action before the disturbance affects the process output. In other words, instead of waiting for an error to occur (as in feedback control), feedforward control measures the disturbance directly and adjusts the control variables to counteract its influence. In a hydrogen production plant, feedforward control can be applied to mitigate the impact of variations in the feed stream composition or flow rate. For example, if the methane content in the natural gas feed to a Steam Methane Reformer (SMR) decreases, a feedforward control system can detect this change and automatically increase the steam flow rate to maintain the optimal steam-to-carbon ratio. This prevents a decrease in hydrogen production and avoids potential coking on the catalyst. Similarly, if the feed flow rate increases, the feedforward control system can adjust the fuel flow to the reformer furnace to maintain a stable temperature profile. By proactively compensating for disturbances, feedforward control improves process stability, reduces variability in the product stream, and enhances overall plant efficiency. Feedforward control is often used in conjunction with feedback control to provide a more robust and precise control strategy.