Long-term bench testing

The testing program for any medical device can be divided into five phases (1) biocompatibility, (2) short-term bench (or in vitro) tests, (3) long-term bench tests, (4) animal (or in vivo) studies, and (5) human clinical studies. For each of these five phases, the type of device and length of time it will be used must be considered in developing test protocols. 

Figure 4 is an example of a long-term bench plant test for a catalyst combination system. Several ten days after the start-of-run, the catalyst system showed stable deactivation. During a stable deactivation period, the catalyst deactivation rate is constant. If the operation mode was a constant product sulfur mode, the temperature-increase-rate of reaction (TIR) was constant and small. Then, after the stable deactivation period, the catalyst system showed a higher deactivation period, in which the TIR became constantly larger than that during the stable deactivation period. The point at which the deactivation rate changes is called a breakpoint. 

Figure 4. Example of catalyst deactivation in long-term bench plant tests.

Figure 7 shows a comparison between the long-term bench plant test results and the commercial operation results using the same catalyst system. Their operation conditions were different for LHSV, feed base, and so on. Here, the required temperature was used to normalize operation conditions and compare activity. The MOC was used to normalize the historical severity. Both deactivation behaviors on the bench plant test and the commercial operation showed fair agreement. The small disagreement in breakpoint might have been caused by the severe operations at the end-of-run in the commercial operation, according to the one-year-operation typically found in Japan. 

Chapter 8 is dedicated to the modeling of heavy oil upgrading via hydroprocessing. Experimental studies for generation of kinetic data, catalyst deactivation, and long-term stability test are explained. Mass and heat balance equations are provided for the reactor modeling for steady-state and dynamic behavior. Simulations of bench-scale reactor and commercial reactor for different situations are also reported. 

A major concern regarding the use of this technology under such rapidly fluctuating pressures is the stability of the adsorbent. Long-term testing of several types of synthetic zeolites and activated carbon in bench-scale, large-pilot-scale, and commercial units has demonstrated that adsorbent lifetimes of well over one year are to be expected in most applications. 

The two other systems were bench-scale plants which had two or three reactors used in series for perfonnance tests of catalysts used in combination and for which intermediates from each reactor could be sampled and analyzed. Thevolumeofeachreactorinthebenchplant was 1000 cc. The two-reactor bench plant was used for the investigation of the activity of catalysts used in combination, and the three-reactor bench plant was used for the investigation of the deactivation behavior of catalysts during long-term operation. 

As long as the service conditions which the lubricant sees are compatible with the existence of a fluid film, there is no reason to believe that the characteristics which govern the behavior of a synthetic fluid in hydrodynamic or elastohydrodynamic lubrication are any different than those which hold for a petroleum oil namely, viscosity, compressibility, and the temperature and pressure dependence thereof. But when failure of the fluid film is suspected and the possibility of metal-to-metal contact arises, the intrinsic antiwear and antiseizure behavior of the synthetic fluid becomes pertinent. Logically these problems should be studied by behavior under conditions related to service in practice, as is mostly the case in the evaluation of conventional lubricants, they are dealt with usually in terms of the commonly used arbitrary bench tests. 

The majority of research to date has been completed on bench and pilot scale facilities. Testing in the field for long-term duration has proved to be somewhat more difficult. Numerous measurement issues have come to our attention, which need to be addressed before the full potential of Hg emission monitors can be realized. 

An electrochemical hydrogen meter based on ternary molten salts with CaCl2 and CaHCl as two components of the electrolyte was constmcted and tested in a bench-top sodium loop. Further tests regarding the long term performance of the meter are in progress. 

However, in actual test measurements, at what point, if any, can it be said that all the feed passes through the membrane That is to say, does not holdup occur on the upstream pressure side For in any kind of short-term or transient test (say, in what might be called a batch or semi-continuous laboratory or bench-scale test), does a reject phase not exist at any point At any point in time, is there no situation in which the feed that has not yet passed through the membrane constitute a reject phase Only for a long-term, steady-state test—with no reject sidestream—can it truly be said that all the feed passes through the membrane. This sort of long-term test, properly speaking, then provides the true measure of membrane permeability for the components within a mixture. Whether or... 

Morita H, Kawase M, Mugikura Y, Asano K (2010) Degradation mechanism of molten carbonate fuel cell based on long-term performance Long-term operation by using bench-scale cell and post-test analysis of the cell. J Power Sources 195 6988... 

The catalyst formulations with the optimum activity, identified as being most selective for given industrial conditions, are typically tested at the next level of R D in pilot-scale reactors closely mimicking industrial plant conditions. Pilot tests are mandatory for further optimization of long-term behavior, and in addition reveal minor details of catalyst performance which escape bench-scale testing, i.e. the formation of minor by-products. Pilot reactor tests are performed under industrial operation conditions, i.e. gas hourly space velocities (GHSV) used in... 

Moreover, the study of pilot reactor performance data is very important in the understanding of the long-term stabiUty of an industrial catalyst. Plant operation often requires a catalyst lifetime of four years without losing too much PA yield during this period of time. PHTHALIMAX , for example, loses about 0.5-1% PA yield per year. To study aging, catalysts are subjected to special stress tests on the bench-scale, as well as pilot units under high temperature and load conditions for... 

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