Detecting and Evaluating Detrimental Factors of Clay’s Longevity, Selecting, and Optimizing an Appropriate Adsorbent for Operating Time Elevation in the Separation Process of Trace Olefins from Aromatics

Abstract

Industrial-scale production of aromatic materials is confronted by the problem of removal of impurities such as olefins. Their removal is an essential requirement in marketability. Catalytic adsorbent clay is the most common material used for the removal of olefins from aromatic streams. The current study is focused on increasing the lifetime of a commercial type of clay by identifying the effective parameters in reducing the adsorbent lifetime. An analysis of 3 years of data from a petrochemical complex showed that water, morpholine, and N-formyl morpholine (NFM) contents in the feed stream are the factors reducing the clay lifetime. Various experiments have been performed to determine the individual impacts of these parameters on the clay lifetime. Reducing the water content from 150 to 70 ppm led to a 20% increase in lifetime, while increasing morpholine content from 55 to 160 ppm and NFM content from 0.55 to 91 ppm resulted in 40 and 75% reduction in lifetime, respectively. Also, six types of conventional commercial adsorbents have been tested to minimize the contents of the above-mentioned components before olefin removal by clay. Among them, silica gel showed the best performance. The optimum weight percentage of silica gel relative to the total loaded clay mass was determined to be 10%, which led to a 2.1-fold increase of clay lifetime if silica gel was loaded into the reactor prior to clay loading.

Selection of suitable bentonite and the influence of various acids on the preparation of a special clay for the removal of trace olefins from aromatics

“…Furthermore, we proved in previous research that N-formyl morpholine, morpholine, and water which exist in the feed stream of the reactor, act as the poisons for the clay and deactivate the Lewis sites (Rouhani and Farhadi, 2020). Therefore, the conversion of olefin reduces with time.…”

“…6d. The reaction was carried out under the following conditions: reaction temperature, T = 185 °C; reaction pressure, P = 16 bar; and weight hourly space velocity (WHSV), 6.56 h -1 (Rouhani and Farhadi, 2020).…”

“…6d). The reaction was carried out at 185°C, a reaction pressure of 16 bar and a weight hourly space velocity (WHSV) of 6.56 h -1 (Rouhani & Farhadi, 2020).…”

“…Colloidal inorganic particles with a size of <2 μm are generally classified as clays regardless of their composition and crystal structure (Rautureau et al, 2017;Stawinski, 2017;Guo et al, 2020). Bentonite is a clay with multiple applications in the oil, gas, petrochemical, food, pharmaceutical, building and agriculture industries (Mannu et al, 2018;Abuchenari et al, 2020;Javed et al, 2020;Rouhani & Farhadi, 2020;Qureshi et al, 2021;Shakiba et al, 2021). The main mineral constituent of bentonite is montmorillonite, a member of the smectite group (Chen et al, 2019).…”

Smart Two‐Dimensional Membranes for Molecular Separations

“…[39] The membranes may degrade after adsorbing these acidic gases. [40] Therefore, future research should elevate the stability of smart 2D membranes by revising fabrication methods or by utilizing chemically robust materials. On the other hand, exploring the membrane's ability to separate complex mixtures, besides simple binary mixtures, is also a field that requires further exploration.…”