Chapter 12 Example

Finding when R(T) = G(T)

Part 1

For an entering temperature of 340 K and an ambient temperature of 310, find the reactor temperature and conversion.

Part 2

Find X and T when the flow rate is increased by a factor of 4.

The following curve gives the G(T) for the reaction.

The plateau region of the curve gives the heat of reaction via the following pathway.

Solution

Part 1

The heat removal curve is

The intercept T = T_C is

This line is shown on the figure below. We see that K

From the intersection of R(T) and G(T), we find that the steady state reactor temperature is 333 K. To find the conversion:

G(T) = X(- DH_Rx)

@ Intersection of G(T) and R(T), G(T) = R(T) = 800

The conversion is 80%

Part 2

We now consider another situation where the flow rate is increased by a factor of 4 and the inlet temperature is 330K and the ambient temperature is 300K.

Solution

For case 2 we find that

The heat removal line is now

and the intercept is

We see that at two points, consequently there are two possible steady states for the temperatures inside the reactor, one at 320K and one at 340K. The corresponding conversions are

and

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