Pellet crushed

Alkylation of benzene with propylene was carried out with the acid zeolites, pelletized, crushed, and sieved at 0.25-0.42 mm diameter. The reaction was performed in an automated high pressure stainless steel reactor, at 3.5 MPa, temperatures ranging from 125 to 200°C, WF1SV from 12 to 18 h"1 referred to the olefin, and benzene to propylene (B/P) molar ratio of 3.5. More details can be found in [7]. 

Pellet crush strength g ASTM D 5230 ASTM D 3313 individual pellet hardness... 

NaX and NaY zeolites (Union Carbide) were exchanged by lithium, potassium, and caesium in a 1 M solution of the corresponding metal chloride at 80°C for 60 min, using a liquid to solid ratio of 10. The samples were then filtered and washed free of chlorides. After drying, the zeolite was pelletized, crushed, and sieved to different particle sizes. 

Catalyst in 10-mm. Pellet 3-mm. Pellet 10 mm. Pellets crushed to 2 to 4- mm. size... 

Single-Pellet Crush Strength Testing of Catalysts... 

Single pellet crush testing has played an integral part in industry for many years. Pharmaceutical companies, for example, consider the mechanical strength of medicinal tablets to be an important property. (1)... 

With the development of catalytic processes such as reforming, hydrocracking and hydrotreating, which utilize formed particles, single pellet crush strength tests were devised by the manufacturers and users of such catalysts. These tests were developed in order to determine the ability of the catalyst particles to maintain integrity during use in catalytic reactors. (2)... 

ASTM Committee D-32 on Catalysts was organized in order to standardize catalyst testing and a Task Group began working on single pellet crush methods with the formation of the committee. 

Results of the second round robin testing of spheres and tablets are shown in Tables I and II. These data are included in ASTM Research Report Number 1004 for Standard Test Method D-4179 for Single Pellet Crush Strength of Formed Catalyst Shapes. 

A test method for single pellet crush testing of catalytic spheres and tablets was developed by ASTM Committee D-32 on Catalysts. A procedure for the single pellet crush strength of extrudates that gives satisfactory interlaboratory variation is yet to be attained. An alternate method will test the assumption that the inter laboratory variations, seen in all round robins, were caused by moisture absorption during testing and the use of a specialized anvil in the test instrument. 

For the same catalytically active material but with different catalyst carriers, different reaction rates and rate equations can be expected. Consider the hydrogenation of 2,4 DNT as discussed in Section 9.2 for 5% Pd on an active carbon catalyst with an average particle size of 30 (im [3]. These experiments were later repeated but with a Pd on an alumina catalyst [5]. This catalyst consisted of 4 x 4mm pellets, crushed to sizes of lower than 40/um in order to avoid pore diffusion limitations. In Figure 2.9 the measured conversion rates are given as a function of the averaged catalyst particle diameter, showing that above a diameter of 80/im the rate measured diminishes. For small particles they determined the rate equations under conditions where there were no pore diffusion lim-... 

Synthesis data Even large pellet Crushed large pellet Eggshell pellet Crushed eggshell pellet Small pellet... 

Pellet crushing tests can determine compression strength. 

ASTM D 5230-96. Carbon black - automated individual pellet crush strength. 

All the catalysts prepared were pelleted, crushed and sieved. The catalytic tests were performed on the 0.6-1.0 mm ftaction. 

A sample of each zeolite was pelletized, crushed and sieved to 40-60 mesh particles, then diluted to 20 wt.% with 40-60 mesh acid washed quartz sand for use in the reactor. 

Mo/HZSM-5 (3Mo/HZ) was prepared as reported in [1, 2, 10], 3 wt.% Mo was introduced by impregnating HZSM-5 (Si02/Al203 mol ratio of 50) with a proper aqueous solution of ammonium heptamolybdate. It was dried at 383 K overnight, calcined in air at 773K for 6 h. The samples were pelletized, crushed and sieved before use. 

Lastly. ASTM D3313 for carbon black pellet hardness does not directly measure carbon black dispersion. This method does measure the individual carbon black pellet "hardness" or crush strength. Carbon black pellets that are too hard will not break up during mixing or disperse properly. Therefore by controlling the pellet hardness of carbon black, one cause of poor dispersion can be controlled. However, there are many other variables that influence dispersion as well. New sophisticated instruments arc now available for measuring carbon black pellet crush strength. 

A fixed bed reactor at atmospheric pressure and reaction temperature of 400-450°C was used. SAPO-34 pelletized, crushed and sieved into 1.1mm catalyst particles was packed into a stainless fixed bed reactor with the top bed diluted with 25 wt % alpha alumina, middle with 50 wt % alpha alumina, bottom 75 wt % alpha alumina. The total amount of SAPO-34 was 5g diluted with 5g total alpha alumina. Also another experiment was done with 1.1 pm SAPO-34 powder packed into the reactor with a-alumina. 

Standard conditions for the measurement of single-pellet crush strength can be found in the ASTM methods D4179 [5] and D6175 [6]. 

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