xisting the bottom sample two-way valve. The valve position was then changed from the nitrogen purge to the sample flask. The rubber ball placed on the flask side outlet was used to pull material from the reboiler through the tubing into the flask. Once enough material was collected for GC analysis, the two-way sample valve was re-positioned back to allow nitrogen flow into the reboiler. The sample flask was disconnected and covered for later GC analysis. The reflux and reboiler samples were both analyzed separately. The procedure, however, was the same. A 1 ml sample was injected into the GC and the resulting GC peak areas were recorded to determine composition. The procedure was completed for each trial condition.Design of ExperimentsThere were two overall variables that were manipulated in the design of experiments. The first was the percentage of the supply voltage (120v) provided to each of four reboiler heaters. We decided to run the entire range of the variac control for the heater. We emphasized on the higher percentage of the heater voltage control in an effort to cause the column to flood. The project team needed the column to flood in order to determine from the HETP vs. Vapor velocity graph what the parameters were for scaling up to the existing column. The second manipulated variable was the cooling water flow rate. The cooling water flow rate was manipulated in order to ensure a sizeable temperature change across the condenser. Wankat presents a reasonable value for the change in cooling water temperature between the inlet and outlet as 30-to-40o F. (1, p.443). Therefore, we used this rule of thumb as a parameter for deciding the values we were going to operate the flow rate of cooling water during each trial. In our design of experiments we replicated all of our individual trail conditions multiple times. A complete summary of the entire design of experiments is located in Appendix B, p. 5-6. Table 1: ...
