Selective production of green light olefins by catalytic conversion of bio‐oil with Mg/HZSM‐5 catalyst

Abstract

BACKGROUND : Light olefins are the basic feedstocks for the petrochemical industry. So far, the olefins yield from bio‐oil is noticeably lower than that from methanol, ethanol and naphtha, and thereby needs to be improved by optimizing catalysts and cracking conditions. The main purpose of this work is to selectively produce light olefins through the catalytic cracking of bio‐oil using the magnesium modified HZSM‐5 catalyst. RESULTS Catalytic conversion of bio‐oil and its model compounds into light olefins was performed using the Mg/HZSM‐5 catalyst. The highest olefins yield from bio‐oil was 0.25 kg olefins (kg−1 bio‐oil) with a carbon yield of 59.3 C‐mol% and nearly complete bio‐oil conversion. The reaction conditions and addition of magnesium into the HZSM‐5 zeolite can be used to control both olefins yield and selectivity. In addition, the yield of light olefins from the pyrolysis of bio‐oil is much lower than the level from bio‐oil catalytic cracking. CONCLUSION Moderately increasing the medium acid sites through addition of Mg into the zeolite effectively enhanced olefins selectivity and improved catalyst stability. The production of light olefins from bio‐oil is closely associated with the chemical composition and hydrogen to carbon effective ratios of feedstock. Copyright © 2012 Society of Chemical Industry

Production of bio‐based p‐xylene via catalytic pyrolysis of biomass over metal oxide‐modified HZSM‐5 zeolites

“…For the used catalyst, two peaks in the DTG curve were distinguished in the range of 350–450 and 500–600 °C, respectively. The first profile in the lower temperature region was attributed to a thermal origin coke formed from the pyrolysis of biomass, which burned easily because the coke was deposited outside the catalyst particles . The second profile in the higher temperature region was attributed to the catalytic origin coke, which was generated mainly by the polymerization of aromatic compounds formed from the catalytic pyrolysis of biomass inside the acid catalyst .…”

“…, the XRD diffraction peaks from the used and regenerated catalysts were similar to those of the fresh catalyst, although the peak intensity for the used catalyst was slight lower than that of the fresh one. In view of the above characterizations of catalysts, the deactivation of the catalysts should be attributed to coke deposition and the reduction of the catalyst acidity, which agreed with previous work . Carbon deposited outside and inside the zeolite could be the main cause of catalyst deactivation, in view of the finding that the activity of the used catalysts could be almost recovered by the removal of coke.…”

Production of gasoline fraction from bio-oil under atmospheric conditions by an integrated catalytic transformation process

“…The chemical compositions, elemental compositions and water content of the light biooil used were shown in Table 1. The use of the light bio-oil with a high water content can reduce the coke deposition and improve the yield of light olefins during the catalytic cracking of bio-oil, as proved by our previous work [8,36]. All analytical reagents used were purchased from Sinopharm Chemical Reagent Company Limited (Shanghai, China).…”

“…The metallic element contents in the catalysts were determined by ICP/AES (inductively coupled plasma and atomic emission spectroscopy, Atomscan Advantage, Thermo Jarrell Ash Corporation, USA). The catalysts were characterized by XRD (X-ray diffraction), N 2 adsorption/desorption, ammonia temperature-programmed desorption (NH 3 -TPD) and TPO (temperature programmed oxidation) analyses, as the same procedures described in our previous papers [8,36]. Briefly, the XRD patterns of the catalysts were obtained on an X'pert Pro Philips diffractometer (Philips,Netherlands) using a Cu Ka radiation (l ¼ 0.15418 nm).…”

Propylene production technology: Today and tomorrow

“…For example, syngas obtained as a result of gasification of biomass can be used for the preparation of methanol followed by conversion of the latter into propylene by the MTP process [193], for the preparation of propylene via the stage of bioDME for mation [194], or for the preparation of propanol and then propylene followed by catalytic dehydration [195].…”