Question: as an engineer in a chemical factory you are required...
As an engineer in a chemical factory you are required to choose the type and size of control valve to be used in the system shown below, FIGURE 2. A pump is used to pass a chemical through a heat exchanger and then on to a reactor. The valve is used to throttle the pipe line connecting the heat exchanger to the reactor. The sizing of the valve is important as the chemical is part of a sensitive reaction and inaccurate additions will ruin the entire batch. The liquid chemical, which has a density of 600 kg/m3, is pumped at 5.5 bar gauge at a nominal rate of 16 litres per second. However the design must permit the flow rate to vary over the range of 8 to 25 litres per second. The design must also allow for a pressure loss of 0.7 bar across the heat exchanger and the pressure in the reactor must be kept at 2.1 bar. It can be assumed that the flow is turbulent and non-choked.
a) Select, giving your reasons, the type of valve you would recommend from:
Ball / Butterfly / Plug / Globe