On‐line management of siloxane breakthrough in carbon contactors using changepoint detection

Siloxane‐induced damage is responsible for a significant proportion of the cost of producing electricity from biogas. The performance of siloxane removal vessels is currently determined by discrete sampling followed by analysis at an external laboratory, making refined process control difficult to achieve. This article introduces the use of on‐line siloxane detection. Siloxane breakthrough curves within this article identified that upon approaching media exhaustion, a concentration of 30 mg/m3 was reached within a short time frame. Consequently, changepoint analysis was evaluated as a method to predict the onset of breakthrough. Breakthrough data were collated from vessels that exhibited both broad‐fronted and sharp‐fronted breakthrough profiles. When applied to broad‐fronted profiles, changepoint analysis provided a 25–45 h early warning of breakthrough. In this case, probabilistic changepoint detection methods facilitated by on‐line analysis provide sufficient process lag time to enable duty/standby switch over before the critical siloxane concentration is reached.