Exit Age Distribution Derivation for a CSTR Using a Step Input Tracer Test with a Laplace Transform

This video describes tracer tests for reactors, which are often used to analyze how water (or any other fluid) flows through a reactor. The concentration in the effluent of a well-mixed or continuously-stirred tank reactor (CSTR) that undergoes a "step input" from a tracer can be determined from a differential mass balance. The mass balance equation is solved in this video using the Laplace Transform, which was introduced in previous videos. The effluent concentration from a step input tracer can be used to assess the cumulative distribution function for water molecules in the reactor, F(t). The probability distribution function for molecules in a reactor in known as the exit age distribution, E(t), which is the derivative of F(t) with respect to time.