Pilot Unit Testing

To test commercial-like formulations under process conditions to ensure that design requirements are achieved. These include activity, selectivity, diffusional. and mechanical properties. 

To optimize process variables, such as space velocity, temperature, and pressure. If activation (for example, reduction or sulfiding) is required, proper procedures are developed at this time. 

3- To carry out long-term lifetime tests. The catalyst encounters components of the feed for the first time. Although the designer may have anticipated the effect of substances such as poisons, sensitivity of the catalyst formulation can only be checked with experiment. For well-behaved processes, lifetime tests of several hundred hours are necessary before long-term 

To develop scale-up data for commerical plant design. Economic evaluations based on projected plant configurations and unit construction are speculative up to this point. Pilot units studies provide more realistic data so that refinement of earlier estimates is possible. Also, any new reactor designs or innovations can be tested. 

To obtain product samples. Large quantities of products may be accumulated for specification assessment. This is useful not only for testing effectiveness of the catalytic process but also in providing data for design of downstream components, safety, or market development, and so on. 

---

One can to outline a general approach for medium selection along with a test sequence applicable to a large group of filter media of the same type. There are three methods of filter media tests laboratory- or bench-scale pilot-unit, and plant tests. The laboratory-scale test is especially rapid and economical, but the results obtained are often not entirely reliable and should only be considered preliminary. Pilot-unit tests provide results that approach plant data. The most reliable results are often obtained from plant trials. 

Table 1. Composition of the aqueous HBr feed used for pilot unit testing...

Pilot Unit Test of Residue Type Catalysts on North Sea Atmospheric Residue... 

Pilot unit tests have indicated that there is an upper limit for the zeolite to matrix surface area ratio (ZSA/MSA) for a residue catalyst. This observation was in contrast to the optimization study, which indicated that the ZSA/MSA should be as high as possible for maximum naphtha yield. An increase in the zeolite surface area is, according to the optimization study, expected to increase both the activity of the catalyst and its naphtha yield. But for catalysts with a high ZSA/MSA ratio, close to four or even higher, the observed naphtha yields have been lower than expected in the pilot unit tests, which indicate that there might be an upper limit for the ZSA/ MSA ratio in a residue application. 

Example 3. In attempting to make meaningful selectivity comparisons between FCC catalysts using pilot unit test data, the testing program must be carefully designed. Several specific criteria must be met ... 

Pilot plants utilizing a single-full-sized reactor tube from a commercial plant are generally used to assess the quaUty and performance of individual catalyst lots and to perform plant or customer ordered process tests. A weU-designed pilot unit is capable of simulating the performance of a commercial plant with great accuracy. 

Obrecht, M. F., Sastor, W. E. and Keyes, J. M., Integrated Design of Field Test Panel Pilot Unit for Investigating Pitting Corrosion of Copper Water Tube by Potable Water Supplies , Proc. 4th Int. Congr. Met. Corr., 1969, 576 (1972)... 

Fig. 1. Schematic of the pilot unit used for catalyst life and heat management testing.

In a pilot scale test using a vessel 1 m3 in volume, a solute was leached from an inert solid and the water was 75 per cent saturated in 100 s. If, in a full-scale unit, 500 kg of the inert solid containing, as before, 28 per cent by mass of the water-soluble component, is agitated with 100 m3 of water, how long will it take for all the solute to dissolve, assuming conditions are equivalent to those in the pilot scale vessel Water is saturated with the solute at a concentration of 2.5 kg/m3. 

Pilot plant tests were made in a cyclic fixed fluidized bed unit over a range of conditions. Catalyst-to-oil ratio was varied from 3 to 5 and WHSV was varied from 32 to 53, inversely. The reactor temperature was held at 975°F for the cracking and steam stripping cycles, and at 1200°F for the regeneration cycles. After regeneration, carbon on catalyst was effectively zero. 

Another test involves use of the Davison full-circulating riser pilot unit (8). This unit is utilized mainly for testing and evaluating the aging properties of the most promising catalyst formulations. 

At the end of the 1970s Statoil cracked a North Sea atmospheric residue for the first time in M. W. Kellogg s circulating pilot nnit in Texas [1]. This pilot unit was qnite large, with a capacity of one barrel a day. The test in this pilot nnit was very snccess-ful and showed that North Sea atmospheric residnes were very suitable feedstocks for a residue fluid catalytic cracker, and that North Sea atmospheric residnes gave very promising prodnct yields. 

One important question we have asked ourselves many times since we managed to crack the North Sea atmospheric residue in the ARCO pilot unit for the first time was if the results are reliable. Does the pilot unit show the same trend and ranking as expected for the commercial FCCU, and can the yields from the pilot unit be used for modeling Initially there was no answer to these qnestions since no commercial data were available for comparison. The only possibility was to compare the tests done in the ARCO pilot unit with the tests done in the pilot nnit at M. W. Kellogg s some years earlier. 

The test at M. W. Kellogg s and the test in the ARCO pilot nnit were done with different feeds, with different catalysts and in different pilot nnits, so it was not expected that the yields should be identical. The feed to the M. W. Kellogg s pilot unit was a synthetic Statfjord atmospheric residne and the catalyst used was a Filtrol 900 catalyst containing nickel and vanadinm contaminants [1]. This pilot unit was also pressurized. In the ARCO pilot unit at Chalmers the feed was a laboratory distilled Statfjord atmospheric residue and the catalyst was an almost metal-free EKZ eqnilibrinm catalyst from Katalistiks. The ARCO nnit is working at atmospheric pressnre. 

---