Quick contact reaction system

Figure 29. QC - Quick Contact Reaction System for FCC - Ross (1990)...

Recent industry advances have been reported such as the Quick Contact (QC) reaction system of the Stone and Webster Eng. Co. (Gartside, 1989). The QC system consists of a new fluidized solids unit which combines patented mixing and separation devices to produce a dilute phase reaction system capable of operating at short residence times (200 ms) and plug flow. 

The kinetics of the microbiological kill reaction is more favorable for bromine. Thus bromine tends to kill microbes more quickly, and for any disinfection time period it will achieve a higher magnitude of kill. This can be important for cooling systems with short disinfection contact times, e.g., once-through systems. 

Experiments with enzymes in SCFs revealed very early that scCOa could strip the essential water from the enzyme. Randolph et al. found that damp immobilized enzyme lost its activity when exposed to bone-dry carbon dioxide. The activity was quickly regained when they injected a small amount of water into the system [12]. Dumont also reported results from an immobilized lipase/C02 system where the conversion rate decreased when the enzyme was in contact with a dry COa/substrate flow. Reaction rates were restored completely when they directed the CO2 flow through a water saturator [13]. 

In the system shown in Fig. 2.3, blended oils and fats feedstocks are continuously and accurately metered into a pressurized, heated vessel, commonly referred to as an autoclave, along with the appropriate amount of caustic, water, and salt. The concentrations of these ingredients are adjusted to yield a mixture of neat soap and a lye phase. At the temperatures ( 120°C) and pressiues ( 200 kPa), the saponification reaction proceeds quickly (<30 min). A recirculation system ensures a residual level of soap in the autoclave to improve contact between the oil and water phases and provides additional mixing. After a relatively short resident time in the autoclave, the neat soap and lye phase reaction blend is pumped into a cooling mixer where the saponification reaction is completed and the reaction product... 

---