On-line process contaminant monitoring and automation in beet sugar factory steam systems.

Abstract

Amalgamated Sugar’s Mini-Cassia factory in Paul, ID was experiencing periodic boiler feedwater
contamination events between December 9 and 18, 2020, resulting in low-pH excursions to the boilers. Existing contamination event monitoring and identification methods historically resulted in slow reaction times by factory boiler operators, as well as subsequent boiler contamination. Once introduced to the boilers, organic contaminants break down into organic acids that quickly consume boiler water alkalinity and often depress boiler water pH to acidic conditions. At a depressed pH, iron is solubilized and potentially re-deposited on critical heat transfer areas of boiler internal surfaces, reducing efficiency and equipment longevity.  In partnership with Mini-Cassia’s water treatment solutions provider, a trial unit of ChemTreat’s RADAR™ was first deployed during fall of crop year 2020. RADAR is ChemTreat’s fluorescence-based sugar detection technology. Its ability to detect contamination events in drips (return condensate) ten minutes faster than the incumbent sugar detector instilled a high level of confidence in RADAR’s detection capability among factory personnel.  During the initial contamination events in December 2020 and subsequent boiler shutdowns, the high level of confidence in RADAR’s capabilities led the factory to directly wire RADAR’s signal output to the factory DCS with data and alarms also flowing through ChemTreat’s CTVista®+ intelligent water management platform. Permanent RADAR sugar detectors were installed in critical locations during crop year 2021 to monitor drips immediately downstream of evaporators and upstream of drip return pumps during campaign and juice run. In addition to fluorescence, the permanent RADAR units monitor pH, conductivity, and ORP. Full auto-divert capability of drips during contamination events was implemented for crop year 2022.  RADAR’s ability to quickly detect contamination in December 2020 provided early warnings that allowed factory personnel to divert drips, use alternative boiler makeup supply, and employ emergency chemistry control procedures to keep the factory operational without experiencing a temporary shutdown caused by steam loss. Had RADAR been more-fully integrated before the contamination events in December 2020, the technology could have saved the Mini-Cassia factory an approximate 48 hours of downtime.