Exercise(1).pdf

Exercise:

Based on figure 1:

Determine the pinch temperature and the minimum hot and cold utility demands.

Plot the Grand Composite Curve.

Assume a value of 10 K for ∆T min .

Figure 1. Simple example of industrial process

Procedure:

1. Stream data for process:

2. Use composite curves.

It is easier to construct separately hot composite curve and cold composite curve.

It can be done by first drawing all hot (cold) streams to identify the relevant temperature

ranges. The heat content in the temperature range is calculated by adding the heat content

of the separate streams. The easiest way is to first add the Fc p values of the separate

streams in the temperature range in question and then multiply by the temperature

difference between the start and end of temperature range.

Construction of hot composite curve:

Construction of cold composite curve:

3. Calculation of interval temperature:

The stream can be represent as:

4. Calculations of heat excess/deficit from equation below:

∆Tmin = 10K; Q h,min = 40 kW, Q c,min = 60 kW

Cascade calculation:

Grand Composite Curve GCC: