14.16. A vaporizer process is shown in Figure Q14.16. The gas pipe (header) has several sources...

   

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14.16. A vaporizer process is shown in Figure Q14.16. The gas pipe (header) has several sources and sinks of gas, and the pressure in the pipe is to be controlled by adjusting the amount vaporized. (a) A cascade control design has been suggested from the pressure to the flow of vapor to the heating medium valve. Evaluate this design using the cascade design criteria. Correct it if necessary. (b) Discuss the response of this cascade design to a disturbance in the heating medium pressure, upstream of the control valve. (c) Discuss the response of this cascade design to a disturbance in one of the source or sink flows. (d) Discuss the response of this cascade design to a disturbance in the liquid temperature. Sources Sinks LC Liquid supply FIGURE Q14.16 Heating medium 14.16. A vaporizer process is shown in Figure Q14.16. The gas pipe (header) has several sources and sinks of gas, and the pressure in the pipe is to be controlled by adjusting the amount vaporized. (a) A cascade control design has been suggested from the pressure to the flow of vapor to the heating medium valve. Evaluate this design using the cascade design criteria. Correct it if necessary. (b) Discuss the response of this cascade design to a disturbance in the heating medium pressure, upstream of the control valve. (c) Discuss the response of this cascade design to a disturbance in one of the source or sink flows. (d) Discuss the response of this cascade design to a disturbance in the liquid temperature. Sources Sinks LC Liquid supply FIGURE Q14.16 Heating medium