environmental engineering dr jawad al-rifai
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Philadelphia University Faculty of Engineering Department of Civil Engineering. Environmental Engineering Dr Jawad Al-rifai . Lecture no. Reactor. Definition:. The tanks in which physical, chemical and biochemical. Ex Water softening & Wastewater treatment. Reactor Types. - PowerPoint PPT PresentationTRANSCRIPT
Environmental EngineeringDr Jawad Al-rifai
Lecture no. Reactor
Philadelphia UniversityFaculty of Engineering
Department of Civil Engineering
Definition:
• The tanks in which physical, chemical and biochemical. Ex Water softening & Wastewater treatment
Reactor Types1- Batch reactor
• Fill & draw types; materials are added to the tank, mixed for sufficient time to allow reaction to occur and then drained. Ex. Laboratory experiment. – Size < 150m3/d– Inexpensive– Easy to operate & build – No influent or effluent –step increase or pulse;
Mass balance Ct/Co=e-kt
Co: concentration at time zeroCt: concentration at time tK: rate of reactionT: time
Continuous flow stirred tank reactor (CSTR)(Completely mixed flow reactor (CMFR))
• Material flows into, through and out of the reactor at all times• uniform throughout the tank• Ex rapid mix or flash mix tank for Water treatment, wastewater
treatment• Ex natural system; lake, mixing of two streams, air in the room• Water flow > 150m3/d• The composition of the effluent is the same as the composition in the
tank• Mass balance express as
Qin = Qout at no reaction
Ct=Co exp (-t/to)
Plug flow reactors (PFR)• Fluid particles pass through the tank in sequence. • Those that inter first leave first. • Assuming no mixing occur in the lateral direction.• As long as the flow conditions remain steady, the
composition of the effluent remains constant.• Ex. Pipes, long narrow rivers, biological treatment in WWTp• MB eq:
In (Cout/Cin)=-K L/U= -k V/QL: length of plug-flow segmentu: Linear velocity, m/s