Plugging tests results

Figure 17. Plugging test results a, pilot microscreen effluents b, filtrates from polishing by crossflow filtration through Ll-pm Acropor filter in axial filter (1.5 psi, 1000 rpm) and in pleated cartridge (loop).

The corrosion rates of the materials of construction are always of importance, but it has been found that, whereas the uniform removal of metal from the hot leg may not impair the load-carrying ability of the container, the deposition of metal in the cold leg can cause the cessation of flow, and the measure of the suitability of an alloy is often the time, under given conditions, that it takes for plugging to occur. Again, the flow velocity and the cross-sectional area are of primary importance in relating test results to operating conditions. 

Flow Tests. Results of the flow tests are shown in Figures 3 through 6. Figure 3 shows the results of a typical run with a brine saturated sand pack wherein a 300 ppm polymer solution in 1 wt% NaCl was injected at a pH of 8.26. Before this, steady state conditions were established in the core by injecting 1 wt% NaCl. The pH values were stabilized at 8.0 and viscosity at around 1.1 cp. The pressure drop across the core stayed constant up to about 8 PV of polymer injection, the pH stayed in the acidic range, and effluent viscosity was consistently lower than the influent value. At about 8 PV the pressure drop started to build and within 2 PV, increased up to about 100 psi essentially plugging the core. No polymer was eluted until the end of the run. 

They were then cut with a diamond saw to form 8-mm-long cylindrical plugs and evaluated for diametral tensile strength using an Instron tester. Testing results of selected experimental agents are provided in Table 2. 

The Parsons/Honeywell EDS also included tests of CATOX units to ascertain if residual mustard agent that might have survived steam treatment in the MPTs and CST had been destroyed (Parsons, 2000a). These units were challenged with 10 mg/m of mustard agent, compared with expected values of less than 3 J,g/m in a full-scale operation. The test results showed that the CATOX units could successfully achieve a destruction and removal efficiency of 99.999 percent at this level for a period of 637 hours. No catalyst deactivation or increased pressure drop was observed. However, there was some plugging of the effluent cooler, presumably by products of combustion of the mustard agent. 

There are other equivalent tests which can show that the vessel is mechanically strong. For pumps, integrity data would involve the frequency of seal repairs, bearing repairs, nature and intensity of vibration, plugging, and corrosion problems. With the mechanical integrity tests, other data is recorded, such as records of inspections and tests, maintenance procedures, establishment of criteria for acceptable test results, and documentation of inspection results. Preventive maintenance (PM) programs are a big part of the PSM. 

Polymer selection for the offshore polymer flood was made by comparing three emulsion polyacrylamides during a 30-day injectivity test. ATI three polymers were chosen for field testing based on laboratory studies. The chosen polymer was selected based on lower overall cost and ease of injection even though some samples failed the core plug test for injectivity. Polymer injectivity was a critical parameter because of the severe pressure limitations of the shallow reservoir. No additional chemicals were required to assist the inversion of the chosen polymer, as were needed for the other candidates. This feature requires one less pump per skid and substantially reduces the possibility of injecting uninverted polymer into the well, which can result in major formation damage. 

Fig. 4—Filtration test results showing plugging and nonplugging polymer solutions. 

A PS(B) solution was injected into a clean core without filtration. The filtration step was eliminated because the particle size distribution peaked at 0.65 /tm and was relativeiy sharp. The test results are shown in Fig. 10. Both face and in-depth plugging were evident, but the face plugging was not as severe as with the PS(P) solution. The conclusion, based on both tests, was that filtration would be required no matter which polymer was selected. It was decided, however, that field injectivity tests should provide the final answer. 

Both the tank in series (TIS) and the dispersion plug flow (DPF) models require traeer tests for their aeeurate determination. However, the TIS model is relatively simple mathematieally and thus ean be used with any kineties. Also, it ean be extended to any eonfiguration of eompartments witli or without reeycle. The DPF axial dispersion model is eomplex and therefore gives signifieantly different results for different ehoiees of boundary eonditions. 

Pore blockage by carbon or heavy products may cause a loss in activity over time. Niemela and Krause39 reported a loss of turnover frequency for Co/Si02 FTS catalysts due to preferential blocking of the narrowest catalyst pores by carbon. Puskas74 found unusually high amounts of wax in the pores on a Co/Mg/ diatomaceous earth catalyst tested in the FTS at 190°C, 1-2 bar, H2/CO = 2.55 for 125 days. In a separate study it was concluded that pore plugging by the waxy products resulted in a fast deactivation of such catalysts.75... 

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