#### 4.9.1 Partial Condensers

A partial condenser condenses only part of the overhead stream and returns this as reflux. This distillate product is removed as vapor as shown in Figure 4-20. If a vapor distillate is desired, then a partial condenser will be very convenient. The partial condenser acts as one equilibrium contact.

**Figure 4-20. Partial condenser; (A) balance envelope, (B) top operating line**

If a mass balance is done on the more volatile component using the mass balance envelope shown in Figure 4-20, we obtain

Vy = Lx + Dy_{D}

Removing D and solving for y, we obtain the operating equation

**(4-50)**

This is essentially the same as the equation ...