End-of-run condition

The long term tests in the SASOL plant as well as in the Schwechat plant were run with outlet temperatures of 450°C, but both plants were also operated with higher loads that caused reactor outlet temperatures of 470°C or even higher. In comparison with the test run at 450°C, only a slight increase in deactivation rate was detectable which demonstrates the thermostability of the catalyst. From the aspect of thermostability, outlet temperatures of 450°-470°C are acceptable. Further considerations including the possibility of overload operation, the SNG specification to be achieved in final methanation, end-of-run conditions, and cost of reactor material will affect the selection of optimum outlet temperature. 

The reactor inlet temperature ranges from 50°C at start-of-run to about 65°C at end-of-run conditions. One important feature of the two-stage system is that the catalyst can be replaced in each reactor separately, without shutting down the ETBE unit. 

Determine the depth of bed required for this application. Also determine the benzene concentration in the bed at the end-of-run condition. 

Nominal Composition of Energetic Materials Used in Chemical Munitions, 22 2-2 Conditions Used in the Commissioning Runs at HAAP, 24 2-3 Test Matrix for the Army Hydrolysis Study at HAAP, 25 2-4 Residual Energetic Material in End-of-Run Hydrolysate Samples, 28... 

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. 

To combat the inevitable loss in desulfurizing activity of the catalyst that must be presumed to occur with time under any predetermined set of reaction conditions, the bed inlet temperature may be increased slowly, thereby increasing the overall temperature of the catalyst bed and so maintaining constant catalyst activity. Thus, depending on the nature of the feedstock, there may be a considerable difference between the start-of-run temperature and the end-of-run temperature. 

Upset conditions Describe the nature and duration of possible anticipated upset conditions. Consider whether the upset conditions are forstart-of-run, end-of-run, both, or will occur during the run. For each upset condition, indicate the presence of corrodents, crack-inducing agents, or electrolytes introduced because of the upset. For autorefrigeration, indicate the anticipated minimum temperature. 

Saim and Subramaniam [36] observed that the end-of-run isomerization rates decreased with isothermal increase in pressure in the subcritical region, but increased with pressure in the supercritical region. In sharp contrast to the activity maintenance observed by Tiltscher and co-workers in a macroporous catalyst, the microporous Pt/Y-Al203 catalyst used by Saim et al. deactivated even at supercritical conditions. A significant portion of the catalyst activity was lost due to the build-up of unextractable coke in the catalyst pores during the subcritical phase of reactor fill-up. In a related work, Manos and Hofmann [37] concluded that the complete in situ reactivation of a microporous zeolite catalyst by an SCF is impossible. This conclusion was based on coke desorption rates and the solubilities of model coke compounds in the SCF. The catalyst deactivation rate can be reduced at supercritical conditions, however, because freshly formed coke precursors can be dissolved by the SCF reaction medium. 

When considering centrifugal machines it is important to base the motor rating on the end of curve condition of the driven machine, because in practice the machine may need to run at this extreme condition for a reasonably long period of time. This condition is generally defined as 125% of the capacity of the machine at the maximum working efficiency point on the head-flow curve for the designed shaft speed. 

Some process has di erent operating conditions at beginning of operation (start of run (SOR)) and at end of operation (end of run (HOR)). Options are to show both operating conditions on one set drawing, but mark each operating condition as SOR or EOR or to develop two sets PFD, one for SOR and the other for EOR. 

The standard melt flow index machine is often used for characterising the flow properties of polypropylene and to provide a rough measure of molecular weight. Under the conditions normally employed for polyethylene (2.16 kg load at 190°C) the flow rate is too low for accurate measurement and in practice higher loads, e.g. 10 kg, and/or higher temperatures are used. It has been found that a considerable pressure drop exists in the barrel so that the flow towards the end of a test run is higher than at the beginning. 

The injector temperature should be determined by the nature of the sample and the volume injected, not by the column temperature. When analyzing biological or high-boiling samples, clean the injector body with methanol or other suitable solvent once per week. Install a clean packed injector liner and a new septum, preferably near the end of a workday. Program the column to its maximum temperature, then cool the column and run a test mixture to check the system using standard conditions. 

For SNG manufacture, it is necessary to reduce the residual hydrogen to a minimum in order to achieve a high calorific value. This is best realized if the synthesis gas, instead of having a stoichiometric composition, contains a surplus of C02 which can be utilized to reduce the H2 content by the C02 methanation reaction to less than 1% according to equilibrium conditions. The surplus C02 must be removed at the end of the process sequence. It is, of course, also possible to operate a methanation plant with synthesis gas of stoichiometric composition then there is no need for a final C02 removal system. The residual H2 content will be higher, and therefore the heating value will be lower (cf. the two long term runs in Table II). 

With flow systems, Eqs. (10) and (10a) apply also, provided steady initial conditions, especially the partial pressures, have been established before the run. Then the time dependence of P and dP/dt (or of the corresponding partial pressures) provides a direct means of estimating (dnsJdt) as a function of time. Towards the end of desorption as the left-... 

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