PDF Publication Title:
Text from PDF Page: 003
Figure 2. PSA ex- perimental process flow schematic. Measure- ments with an asterisk (*) indicate sensors with auto- matically logged analog outputs. columns would be requFireigdutoreall2o:wPfSorAcoenxtipneuroiums epnrotdaul cpt rocess Sflteopw3:sWchheemn athteicn.itMrogeeansupruerimtyeonftsthwe pitrhodaunct gas nears asterisk (*) indicate sensors with automatically logged analog outputs. collection. As an operational example, consider the backfill its lower allowed limit, the product release valve is closed. cycle in Figure 1(a) as applied to nitrogen production. In this case, the adsorption packing is chosen and used to preferen- tially hold up oxygen (rather than nitrogen) in the column dur- ing the period of product collection. Below, a short description of each process step in the cycle is described, along with an associated statement of gas/surface interaction. Step 1: Freshly purged and at a low (e.g., atmospheric) pres- sure, Column 1 is quickly pressurized with an air feed stream to the system’s selected working pressure. Simultaneously, Column 2 is saturated with adsorbed oxygen at the work- ing pressure, and is vented to the atmosphere (blowdown). In Column 1, the adsorption packing quickly fixes oxygen onto its surface, allowing proportionally more nitrogen to remain in the gas phase. As the column pressure increases, the equilibrium surface concentration of adsorbed oxygen rises correspondingly. In Column 2, the drop in total pres- sure reduces the partial pressure of oxygen in the gas phase, changing the system gas/surface equilibrium in the opposite direction; oxygen gradually desorbs from the packing and exits the column until a new gas/surface equilibrium condi- tion is reached at atmospheric pressure. Step 2: The product valve is opened for Column 1, and an initially nitrogen-rich stream is sent for collection. A small amount of this product stream is diverted to Column 2, where it surrounds the packing with a low-pressure, oxygen-deficient environment; this causes further oxygen desorption in accor- dance with the continuing gas/surface equilibrium approach. The vent valve from Column 2 remains open, allowing for the continued purging of the column. The stream diversion to Column 2, which serves to further purge its adsorbed oxygen, is known in practice as “backfilling.” In Column 1, oxygen from the feed air continues to adsorb on the packing at the system’s operating pressure until the packing nears saturation. The feed to Column 1 and the purge valve for Column 2 are both closed, and Column 2 is now charged with feed air while Column 1 is blown down. Step 4: Column 2 provides backfilling to Column 1 while generating more nitrogen-rich product gas until the minimum product purity is once again reached. Closing the product, feed, and purge valves once again resets the system to the cycle’s beginning (Step 1). Industrial pressure swing adsorption systems operate by continuously repeating such cycle steps, executing them with automated valves and some form of integrated product gas storage.[5] Typical systems may take many complete cycles to reach a round trip steady-state operation[6,7] as well. The time-intensive impact of each of these characteristics indicates that an experimental system designed for student laboratory operation should be designed for the direct study of cycle steps, rather than system performance over a number of com- plete cycles. Following this logic, a pressure swing adsorption system for the separation of air in the Unit Operations Labora- tory was built to achieve flexible operation through hands-on manipulation and automated data acquisition. LABORATORY SETTING AND EXPERIMENTAL MODULE The instructional goals and teaching methods for the Unit Operations Laboratory at the Colorado School of Mines (CSM) has been thoroughly described elsewhere.[8,9] The pri- mary functional difference between the laboratory at CSM and its counterparts at most other universities is that it is offered as a stand-alone summer (field session) course, which allows students an extended experimental work time versus what is generally possible for typical lab courses offered during an academic semester or quarter. The scheduled lab times enable 46 2 Chemical Engineering EducationPDF Image | PRESSURE SWING ADSORPTION IN THE UNIT OPERATIONS
PDF Search Title:
PRESSURE SWING ADSORPTION IN THE UNIT OPERATIONSOriginal File Name Searched:
PSA-lab.pdfDIY PDF Search: Google It | Yahoo | Bing
CO2 Organic Rankine Cycle Experimenter Platform The supercritical CO2 phase change system is both a heat pump and organic rankine cycle which can be used for those purposes and as a supercritical extractor for advanced subcritical and supercritical extraction technology. Uses include producing nanoparticles, precious metal CO2 extraction, lithium battery recycling, and other applications... More Info
Heat Pumps CO2 ORC Heat Pump System Platform More Info
CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com (Standard Web Page)