Acidic and Catalytic Properties of Modified Clay for Removing Trace Olefin from Aromatics and Its Industrial Test

Abstract

The commercial clay modified with zeolite and La 2 O 3 was characterized by thermoprogrammed desorption (t.p.d.) of NH 3 and pyridine adsorption followed by Fourier transform infrared spectroscopy (FTIR). The result showed that the weak Lewis acid plays an important role in the alkylation reaction between olefin and aromatics which obeyed the carbonium ion mechanism. The industrial test was conducted in the 450kt/a industrial PX device at Sinopec Zhenhai Company for removing trace olefins from aromatics. It has been proved that the life cycle of the catalyst was 5.3 times that of the commercial clay. The kinetics formula for deactivation rates was explored and the result showed that the rate of clay was much higher than the catalyst deactivation rate.

Acid properties and catalysis of USY zeolite with different extra-framework aluminum concentration

“…In order to protect the adsorbent, the bromine index which is an indicator of the presence of olefinic bonds is required to be less than 20 mg Br/100 g. Therefore, these contaminants must be removed before aromatic streams are sent to the petrochemical processes. It has been approved that these harmful impurities can be removed by acid-catalyzed alkylation of the appropriate aromatics [3][4]. In commercial plants, the purification process uses the clay treating [5] or the modified clay treatment.…”

Acid-Modified Hierarchical Porous Rare-Earth-Containing Y Zeolite as a Highly Active and Stable Catalyst for Olefin Removal

“…In the spectra, vibration bands were observed in the wavenumber range of 1400–1600 cm –1 , which were attributed to the interaction of pyridine with Lewis (L) and Brønsted (B) acid sites on the sample surface. 8 , 13 The band at around 1450 cm –1 was attributed to pyridine adsorbed on the L acid sites. Another band at around 1490 cm –1 was ascribed to the contributions of both the L and B acid sites.…”

Bifunctional Catalysts Based on Tungsten Hydrides Supported on Silicated Alumina for the Direct Production of 2,3‐Dimethylbutenes and Neohexene from Isobutene

“…Furthermore, two intense signals at ñ = 1454 and 1625 cm À1 attributed to pyridine vibrations confirm the presenceo fL ewis acid sites (L). [41,42] The B/L ratio evaluated from the integration area of the signals at ñ = 1454 and 1540 cm À1 ( Figure S4) indicated that as the silica coating increasedt he amount of Bs ites increased and that of Ls ites decreased.…”