Micro activity test

As mentioned in Section 2.2 (Fixed-Bed Reactors) and in the Micro activity test example, even fluid-bed catalysts are tested in fixed-bed reactors when working on a small scale. The reason is that the experimental conditions in laboratory fluidized-bed reactors can not even approach that in production units. Even catalyst particle size must be much smaller to get proper fluidization. The reactors of ARCO (Wachtel, et al, 1972) and that of Kraemer and deLasa (1988) are such attempts. 

The first step in E-cat testing is to bum the carbon off the sample. The sample is then placed in a MAT unit (Figure 3-13), the heart of which is a fixed bed reactor. A certain amount of a standard gas oil feedstock is injected into the hot bed of catalyst. The activity i.s reported as the conversion to 430°F (221°C) material. The feedstock s quality, reactor temperature, catalyst-to-oil ratio, and space velocity are four variables affecting MAT results. Each catalyst vendor uses slightly different operating variables to conduct micro activity testing, as indicated in Table 3-2. 

This paper gives an example of the response of one equilibrium catalyst to the three basic Demet procedures and to modified versions of these procedures. The catalysts are evaluated by elemental analysis and by their cracking performance, as determined by the micro activity test (MAT). 

Cracking performance. Micro activity test results for the different preparations are given in Table II. Variants of all three basic Demet procedures (see Fig. 1-3) can be used to improve the performance of this equilibrium catalyst. 

The experimental studies using industrial feedstock are carried out in a modified MA.T. (micro activity test) [10], The reaction conditions are presented in table 1, The catalyst is NOVA D equilibrium catalyst from Grace Davison Co, The equilibrium catalysts are previously coked under the same reaction conditions to get partially deactivated samples. The method using the conversion versus initial coke content from experiments to determine the deactivation function, is described in [10]. Three different feedstocks are used (table l). 

Notwithstanding the possibility of doing detailed simulations with bench or pilot scale riser reactors, the traditional Micro Activity Test (MAT) remains the main tool for basic FCC research and catalyst and feedstock evaluation and monitoring. 

ASTM D-3907-86 Method for testing FCC catalysts by micro-activity test. 

If water was added to the 15% Si02 co-gel to fill the pore voids a partially recrystallized boehmite was formed with a surface area of 464 m /g and with a pore volume of 1.8 oc/g. If water was added to the 15% Si02 co-gel to form a slurry and then dried and calcined at 500 a partially recrystallized bodunite was formed with a surface area of 334 m /g. steam treatment at 760 of this second, small pore, bodunite-like silica-alumina resulted in no change in the surface area. The gas oil cracking activity of the steamed sample was definitely hi er than that for the amorphoias co-gel, i.e., a Micro Activity Test (MAT) Activity Number of 38 (see Table 1.). 

Micro Activity Test Activity Numbers. (See references 4-5)... 

Catalytic cracking. A modified micro activity test (MAT) was used for testing cracking performance. The feed oils used in this study were a... 

Several types of FCC testing equipment are described in literature, varying from the more traditional standardized micro activity test (MAT) and fluidised bed reactors to complete riser-regenerator combinations. Also other designs such as a pulse reactor, or a very short contact time reactor have been reported in literature (7-9). 

The Microsimulation test (MST). Modification of the operating procedure and experimental conditions of a convential micro activity test (MAT) has led to the so-called microsimulation test (MST, see Figure 3). Basically, the reactor is a fixed bed with transient operation during the catalyst contact time. A complete description of the operation and design of the MST reactor is given by O Connor in (11). Table I gives an overview of the main differences between the MR and the MST. 

For light feedstocks and low metals operations, determining the coke selectivity by making use of yields from a Micro Activity Test (MAT) is generally the preferred route. Several modifications of the test and test procedures, for... 

Micro activity test (MAT). This test was developed and standardized by ASTM (ASTM-D-3907). In the MAT test, a sample of cracking catalyst is contacted with gas oil in a fixed-bed reactor. Gas chromatographic analysis on gas and liquid products is used to determine the yield structure. Recently, the MAT conditions have been adapted to simulate commercial units more accurately in terms of contact times. A higher catalyst activity results in improved conversion and higher regenerator temperature. 

In this work Micro Activity Tests with an aluminosilicate MCM-41 and a silica-containing VPI-5 were carried out using n-hexadecane as the model feed. Special emphasis was given to the catalytic activity, thermal stability and selectivity of the different materials studied in comparison with a commercial equilibrium FCC catalyst. Additionally, the possible structural and textural changes during the above-mentioned catalytic process were characterized. 

In the present work we report the results we have obtained from optimizing a synthesis procedure described by Perez et al. [4] and Martens et al. [6] for selected silicon sources and different Si/Al ratios in the synthesis gels. Results from Micro Activity Tests (MAT) at 524°C with atmospheric residue as the feed, and pulse reactor tests at 480°C with trans-decalin as feed, are discussed. 

Cracking properties of a Si-VPl-5 (Si/Al=0.4 in the gel) and the reference catalyst were also investigated by Micro Activity Tests (MAT), using a short contact time MAT (SCT-MAT) which is a modified version of the ASTM MAT with better correlation to a commercial unit 1 g of atmospheric residue was fed to the reactor during 30 seconds at 524°C. Liquid products were collected at 0°C and analyzed on a HP 5880 Sim Dist GC, while gas products were collected over a saturated KCl-solution and injected on a HP 5880 Refinery Gas Analyzer. 

Fluid Catalytic Cracking (FCC) is one of the most important process in oil refining. The evaluation of the catalysts in the laboratory scale is often carried out in a micro-reactor, the so called micro-activity test [1-3] (MAT). Coke formation plays an important role in the deactivation of FCC catalysts, which can be deactivated either permanently (loss of surface area, zeolite collapse, metals) or temporarily deactivated (coke). 

M..Forissier and J.R.Bemard, Modeling the Micro-activity Test of FCC Catalysts to Compute... 

The micro-activity test (MAT) and n-hexane cracking have being used to characterize FCC catalyst. The complex nature of MAT does not permit a specific conclusion regarding of the metallic state. On the other hand, n-hexane requires strongly acidic sites and was not very sensitive to probe deactivated catalysts. 

The amount of sample required for analysis can also pose a problem in some cases when only small quantities are available (e g. fluid catalytic cracking-micro-activity test - FCC-MAT). 

The traditional Micro Activity Test (MAT) remains the main tool for basic FCC research and catalyst and feedstock evaluation (O Connor and Hartkamp, 1988 Campagna et al., 1986). This test was developed because of its simplicity, reproducibility and quickness of evaluation in comparison to pilot units. The MAT method is an ASTM procedure (ASTM D-3907-80) which comprises a fixed bed of 4 grams of catalyst, operated with continuous oil vapour feed for 75 seconds at a temperature of 482°C under a cumulative catalyst to oil ratio of 3. This specific form of the MAT procedure has not been successful in predicting commercial unit performance and provides only very limited information on selectivity (Carter and McElhiney, 1989 Mauleon and Courcelle, 1985 O Connor and Hartkamp, 1988). In general, catalyst choice based solely on MAT data is questionable and rarely done and it is not suited for simulating commercial operation. Its main use is in the relative comparison of activity of FCC catalysts (Humphries and Wilcox, 1990). 

Micro-activity tests (MAT) are used to measure activity at a constant level and determine the appropriate catalyst makeup rate. 

Lindfors, C., PaasikalUo, V., Kuoppala, E., Reinikainen, M., Oasmaa, A., Solantausta, Y., 2015. Co-processing of dry bio-oil, catal3dic pyrolysis oil, and hydrotreated bio-oil in a micro activity test unit. Energy Fuels 29, 3707—3714. 

Samples were characterized by XRD (Siemens D5000 XRD spectrometer), FE-SEM (Field Emission Scanning Electron Microscope, Hitachi S-4800), textural properties were determined by N2 adsorption/desorption experiments) and NH3-TPD (temperature-programmed desorption of ammonia). Catalytic properties of samples were tested in the cracking of a Bach Ho petroleum residue from Vietnam (370-500°C fraction) as heavy feedstock using a MAT 5000 micro activity testing system. The reaction conditions were 482°C, WVH=27, catalyst to feedstock ratio 3/1, reaction time 45 sec. 

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