Formose Project - Process
The acidic Dequest® effluent containing very dilute waste formalin (formaldehyde solution) is first collected in the formose buffer tank, equipped with a vent scrubber to eliminate any local emissions. The effluent from this tank is pumped to an inline mixer where it is neutralised with Calcium Hydroxide solution ‘slaked lime’ before entering the waste heat exchanger (WHE). The neutralised effluent stream leaving the WHE will be close to the optimum reaction temperature of 80oC and after temperature adjustment will pass to the Continuously Stirred Tank Reactor (CSTR). The effluent in the CSTR will react with the previous contents to partly convert to formose sugars. Further conversion will take place in the Plug Flow Tank Reactor (PFTR) before leaving via the WHE.
The effluent leaving the WHE will be cooled to ~30 to 50 °C and mixed with the remaining site effluent in the existing neutralisation system. The final effluent after pH adjustment will be stored and discharged into the Severn estuary.