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Explain the theory behind a steady state continuous stirred-tank reactor (aka CSTR) and as well an unsteady state CSTR.
Steady state cstr having constant volume cstr and isothermal operation. There is no accumulation and inlet and outlet flow rate is equal becuase inside volume of liquid is constant it doesn't vary with time and oulet concentration and inside tank concentration at any time is same due well mixed operation.
If reaction goes A to B then
Rate of reaction (-rA) =k. CA
Material balance required no need for energy balance because it is isothermal operation.
Material balance
Input flow rate of A - output flow rate of A - disapperance due to reaction = accumulation
If volumetric flow rate is v and Volume is V initial concentration is CAo Then
vCAo - vCA - (-rA) V = 0
Unsteady state cstr is having accumulation means volume of liquid inside tank changes with time. In this we are derived time required such that it goes steady state. If we take isothermal operation then there is no energy balance so we use only material balnce with accumulation.
Material balance for above given reaction
vo CAo - vCA - (-rA)V = V dCA/dt
And this is integrate and find out time and concentration relation which can plot also conversion and time which are more useful in industry.