Preparation Of Aromatic Hydrocarbons Research Articles

Preparation of aromatic hydrocarbons from pinecone pyrolysis synergistically catalyzed by Ca–Fe and HZSM-5

In this study, a combination of Ca–Fe and HZSM-5 catalysts for enhancing the aromatic hydrocarbons yields from pinecone pyrolysis was proposed. The catalysts performance and the enhanced mechanism of aromatic hydrocarbons generation were investigated by pyrolysis–gas chromatography–mass spectrometry (Py-GC/MS) and a bench-scaled fixed bed reactor. The catalysts crystallization and pore structure characteristics were characterized by X-ray diffraction (XRD) and N2 adsorption/desorption. The results showed that the combination of Ca–Fe and HZSM-5 catalysts produced the largest peak area and the highest relative content of aromatic hydrocarbons relative to HZSM-5, CaO/HZSM-5 and Fe/HZSM-5 catalysts. Relative to single HZSM-5 catalytic pyrolysis, the introduction of Ca–Fe components increased the yield of aromatics, especially increased the yield of benzene, toluene, ethylbenzene and xylene (BTEX) to 17.21 mg/g, with an increase of 61.60 %. The heterotopic arrangement of pinecone, Ca–Fe catalyst and HZSM-5 catalyst facilitated the production of high-quality aromatic hydrocarbons relative to the in situ catalytic pyrolysis technique. The Ca–Fe bimetallic catalyst decomposed the primary volatiles from pinecone pyrolysis into oxygenated compounds with smaller molecular weights, thereby increasing the proportions of pyrolysis volatiles entering the HZSM-5 channels, and subsequently enhancing the yield of aromatic hydrocarbons. This study implies that the combination of Ca–Fe and HZSM-5 catalyst is a promising approach for converting biomass materials into aromatic hydrocarbons.

Preparation of aromatic hydrocarbons from fast pyrolysis of waste medical mask catalyzed by modified HZSM-5

The safe and efficient utilization of waste medical masks has attracted worldwide attention. Fast pyrolysis with the catalysis of zeolites can provide a promising route for the production of value-added aromatic hydrocarbons from waste medical masks. Herein, HZSM-5 was employed and modified by metal loading (Ga, Mo) and alkali treatment for the ex-situ catalytic pyrolysis of mask filters. The non-catalytic pyrolysis of mask filters only led to a low yield of aromatics. When HZSM-5 catalysts were employed, the liquid long-chain olefins, cycloalkanes, and alcohols, as well as gaseous light hydrocarbons were mainly converted into aromatics. According to the micro-scale pyrolysis experiments, the alkali treatment as well as Ga and Mo loading further promoted the generation of aromatics, with aromatic yields of 52.8 wt%, 54.1 wt%, and 46.3 wt%, respectively. For alkali treatment, the NaOH concentration of 0.3 mol/L was most effective for aromatic production, due to the moderate change in the pore size. For metal loading, Ga loading had better performance than Mo loading because the former resulted in a higher specific surface area while the two modified catalysts possessed similar acid activity. When the two modification methods were combined, the yields of aromatics increased to 56.7 wt% and 60.3 wt% under the catalysis of Mo/Na-HZSM-5 and Ga/Na-HZSM-5. Based on the lab-scale experiments, the aromatic yield could reach 63.0 wt% with the catalysis of Ga/Na-HZSM-5, accompanied by a high selectivity of 87.6% for monocyclic aromatic hydrocarbons (MAHs). In summary, both MAHs and polycyclic aromatic hydrocarbons (PAHs) were promoted with these catalyst modification methods by expanding the mesopore size and adjusting acid site distribution, with greater promotion on the formation of MAHs.

Preparation of aromatic hydrocarbons from catalytic pyrolysis of digestate

Catalytic pyrolysis of digestate to produce aromatic hydrocarbons can be combined with anaerobic fermentation to effectively transform and utilize all biomass components, which can achieve the meaningful purpose of transforming waste into high-value products. This study explored whether catalytic pyrolysis of digestate is feasible to prepare aromatic hydrocarbons by analyzing the thermogravimetric characteristics, pyrolysis characteristics, and catalytic pyrolysis characteristics of digestate. For digestate pyrolysis, an increase in temperature was found to elevate the CO, CH4, and monocyclic aromatic hydrocarbon (benzene, toluene, and xylene; BTX) content, whereas it decreased the contents of phenols, acids, aldehydes, and other oxygenates. Furthermore, the catalytic pyrolysis process effectively inhibited the acids, phenols, and furans in the liquid, whereas the yield of BTX increased from 25.45% to 45.99%, and the selectivity of xylene was also increased from 10.32% to 28.72% after adding ZSM-5. ZSM-5 also inhibited the production of nitrogenous compounds.

Preparation of Aromatic Hydrocarbons from Catalytic Pyrolysis of Digestate

Preparation of Aromatic Hydrocarbons from Catalytic Pyrolysis of Digestate

Effects of NaOH on the catalytic pyrolysis of lignin/HZSM-5 to prepare aromatic hydrocarbons

The pyrolysis of alkali lignin in black liquor to prepare bio-chemical is attracting increasing attention. In addition to alkali lignin, black liquor also contains a large amount of sodium salts (e.g., NaOH and Na2CO3). In the present study, the fast pyrolysis of lignin was carried out in a fixed bed reactor. The effect of NaOH on the preparation of aromatic hydrocarbons by catalytic pyrolysis of lignin/HZSM-5 was investigated; the effect of pyrolysis temperature and the NaOH to lignin ratio on the yield and relative content of aromatic hydrocarbons was also investigated, and the mechanism underlying the promotion of aromatic hydrocarbon formation due to NaOH was studied by using guaiacol as a model compound. The results indicated that the addition of NaOH improved the in situ hydrogen supply and promoted the removal of methoxyl groups, thus, the relative content of monocyclic aromatic hydrocarbons increased from 54.95 % to 66.92 %.

Preparation of Aromatic Hydrocarbons from Catalytic Pyrolysis of Microalgae/Palm Kernel Shell Using PKS Biochar-Based Catalysts

The objective of this work was to prepare a biochar-based catalyst with higher reactivity and longer life cycle to convert biomass to aromatic hydrocarbons. The palm kernel shell (PKS) biochar-base...

Preparation of aromatic hydrocarbons: H. Nakajima; M. Furuya Technology Research Association for New Application Development fot Light-Weight Fractions Jpn Kokai Tokkyo Koho 87,175,430; 87,175,430; 87,175,431; Aug. 1, 1987; Appls. Jan. 28 and Jan. 29, 1986

Preparation of aromatic hydrocarbons: H. Nakajima; M. Furuya Technology Research Association for New Application Development fot Light-Weight Fractions Jpn Kokai Tokkyo Koho 87,175,430; 87,175,430; 87,175,431; Aug. 1, 1987; Appls. Jan. 28 and Jan. 29, 1986

Catalytic properties of zeolites with various structures and chemical compositions in the preparation of aromatic hydrocarbons from methane

A dependence of the selectivity and reaction rate in the preparation of aromatic hydrocarbons from methane on ZSM zeolites in the present of some nitrous oxide on the chemical composition and structure of zeolite catalysts has been examined. The activity is shown to increase with increasing the concentration of decationated sites of the ZSM zeolites. The low activity of the Y zeolite is likely to be due to a fast poisoning of its acid centers by coke formation.

Preparation of aromatic hydrocarbons from methane in the presence of O2

It has been revealed that methane conversion on ZSM zeolites in the presence of O2 can yield hydrocarbons having molecules with more than one carbon atom. A dependence of the selectivity of this process on the chemical composition and structure of the zeolites and the pressure of the reaction mixture has been studied and a reaction mechanism for this process is suggested.

Preparation of aromatic hydrocarbons from tuimazin gasoline by two-stage a romatization

1. By two-stage aromatization of the heptane-methylcyclohexane fraction of Tuimazin gasoline in presence of platinized charcoal (10% Pt) its toluene content can be raised from 5 to 30% by volume. 2. Like the platinum catalyst, a nickel-copper-alumina catalyst (67.5% Ni + 2.5% Cu + 30% Al2O3) can be used for the dehydrogenation of cyclohexanes. It is less stable than the platinum catalyst, but it can be regenerated in situ. 3. By two-stage aromatization of the octane-dimethylcyclohexane fraction of Tuimazin gasoline in presence of a nickel-copper-alumina catalyst its aromatics (mainly xylene) content can be raised from 8 to 33% by volume. Here the preliminary isomerization of cyclopentanes to cyclohexanes in presence of aluminum chloride accounts for 17% increase in the xylene content. 4. Removal of the 91–103° fraction from the whole Tuimazin gasoline does not lower its octane rating.

Preparation of aromatic hydrocarbons by the catalytic treatment of the products of the coking of coal and of the pyrolysis and thermal cracking of petroleum

1. An investigation was made of the catalytic aromatization of thermal-cracking distillates and the dealkylation of the hydrocarbons of coal-tar distillate in presence of toluene and of the crude toluene fraction of light pyrolysis oil. 2. Under optimum conditions the use of somewhat elevated pressure (3–15 atm) accelerates the reactions of aromatization, dealkylation, and alkylation of the original hydrocarbons and directs the process toward the maximum formation of xylenes. Depending on the composition of the raw material, the yield of xylene fraction on the amount of material consumed in one passage varies in the range 37.5–38%, that of benzene in the range 14–27.2%, that of light gasoline in the range 2.2–8.5%, and that of the alkylbenzene fraction of b.p. 149–180° in the range 14.4–20.6%. 3. The presence of toluene in the mixture favors the aromatization of the hydrocarbons of cracking distillate with appreciable suppression of coke- and gas-formation processes. In the formation of xylenes, in addition to the aromatization of the original hydrocarbons, the dealkylation of polyalkylbenzenes and the conjugated alkylation of toluene are of great importance. The xylene fractions of the catalyzates consist mainly of a mixture of the three isomeric xylenes and are notable for their low contents of ethylbenzene.