Conversion troubleshooting

Often, the feed rate or the conversion cannot be increased because the unit is circulation-limited. Effective troubleshooting of this limitation requires having in place a methodology such as the one shown in Figure 8-1. 

Luckily, there are circuits that fill all of the power requirements listed above and more. SPICE can be an indispensable tool for designing, troubleshooting, and characterizing power conversion circuits. 

Hollow fiber modules, or permeators, are precisely machined units containing bundles of hollow fine fibers positioned parallel to and around a perforated center feed-water tube, with only one or two bundles per pressure vessel. They are widely used for brackish and seawater applications. Hollow fiber modules exhibit a low flux rate (permeate flow per unit membrane per unit time) and can foul easily but tend to have high conversion factors (the percentage of feed flow converted to permeate), typically 50 to 55%. This makes them suitable for both small and large RO systems. They are easy to troubleshoot, and bundles are easy to change in the field. 

Reduce the cost of chemical intermediates by improving existing chemistry. Troubleshooting frequently provided leads for process evolution and also ideas leading to better chemistry for the conversion of fermentation products to chemical intermediates—for example, cephalosporin C to 7-ACA. Again, product quality is the most important guiding parameter. 

The process takes hydrogen and nitrogen (in a 3 1 ratio) to make ammonia. The reactor is limited by equilibrium you will prepare the spreadsheet in stages to aid troubleshooting. Thus, first prepare a spreadsheet as shown in Figure 5.8, using 25 percent conversion per pass in the reactor. 

Safety, environmental protection, and equipment protection (see Section 16.7 this could include redundant temperature sensing and alarms on reactors and reboilers handling corrosive chemicals such as HF), smooth operation, product quality, profit, monitoring, diagnosis, and troubleshooting. Identify the objective and select a pertinent variable. Direct measurement of the variable is preferred. If direct measurement is impractical, select an inferential or calculated variable. For example, temperature can infer conversion and composition. 

Older motor drive systems generally consist of a DC brush motor, a power conversion unit (PCU), and operator controls. A frequent problem with the motor itself Is worn brushes these should be replaced at regular Intervals as recommended by the manufacturer. In troubleshooting an extruder drive, one should follow the procedure recommended by the manufacturer of the drive. A typical troubleshooting guide for a DC motor is shown in Table 11.2. 

Catalyst activity can be measured in a sophisticated laboratory with decent reproducibility. An activity of 70+ is good less than 50 is very bad. Since the lab analysis typically is a service provided by catalyst vendors, turnaround time for results may be one week. The troubleshooter faced with a sudden loss in feed conversion may not have a week to wait. The plant manager may need to know right away if the loss in FCCU gasoline production is due to a more refractory (i.e., harder to crack) feed or poisoned catalyst. 

Mackay, R. 2004. The Practical Pumping Handbook. Oxford, U.K. Elsevier. As the title suggests, this is a very practical treatment of pumping, piping, and seals. Unlike some other similar works, Mackay s work explores pump selection and pmchasing, troubleshooting, and maintenance, in addition to more standard content on the topic. Contains conversion tables and formulae and a brief bibliography at the end of the volume. 

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