Conversion of Syngas to LPG and Aromatics Over Commercial Fischer-Tropsch Catalyst and HZSM-5 in a Dual Bed Reactor

The commercial Co-based Fischer-Tropsch catalyst and HZSM-5 were tested in a single reactor process. FT catalyst was evaluated at 463 K, whereas HZSM-5 was evaluated at various temperatures (523, 573, and 623 K). The effect of syngas flow rate, HZSM-5 temperature and loading on liquefied petroleum gas (LPG) and aromatics selectivities were investigated. HZSM-5 addition suppressed the formation of CO₂ and CH₄, and remarkably enhanced the simultaneous formation of LPG and aromatics. The optimal operating conditions were identified as: T_HZM-5 = 623 K, HZSM-5 loading = 2.5 g, and GHSV = 4.8 L_syngas/(g_cat h).     

Effect of operating conditions on alkylation of toluene with methanol

P-xylene (PX) is widely used as a raw material of synthesis of terephthalic acid (PTA) and polyester. With the demand of PTA and polyester, PX is demanded eagerly. The process for preparing PX through alkylation of toluene with methanol has been concerned widely. In an experiment HZSM-5/Al₂O₃ catalyst was prepared by loading pseudoboehmites on HZSM-5. The strength of B acid is adjusted, so side reactions can be controlled effectively. The optimum operating conditions are that molar ratio of toluene to methanol is 2.0, reaction temperature is 410°C, carrier gas flow is 7 mL/min, and WHSV is 1.0 h^?1 by investigating the effect of operating conditions on toluene conversion and PX selectivity. Toluene conversion and PX selectivity are up to 46.2% and 68.07%, respectively, under the optimum operating conditions.     

Optimization of reaction condition on the product selectivity of Fischer–Tropsch synthesis over a Co–SiO2/SiC catalyst using a fixed bed reactor

The Fischer–Tropsch (FT) synthesis is an important method for producing valuable key raw materials such as heavy and light hydrocarbons in various industries. The effects of process conditions (temperature of 503–543 K, pressure of 10–25 bar, and gas hourly space velocity (GHSV) of 1,800–3,600 Nml g _cat^?1 h^?1) on the FT product distribution using Co–SiO₂/SiC catalyst in a fixed bed reactor were studied by the design of experimental procedure and the Taguchi method. The optimization of the reaction conditions for the production selectivity of C₂–C₄ and heavy hydrocarbon (C₅₊) that has not been completely indicated elsewhere was investigated. The effect of operating conditions on the average carbon number distribution, dispersion, and skewness was also studied. Data analysis indicated the highest selectivity for the light hydrocarbons at a pressure of 20 atm, GHSV of 2,400 Nml g _cat^?1 h^?1, and temperature of 543 K resulting in a highest selectivity for heavier hydrocarbons (C₅₊) and the minimum amount of methane in the reaction products that is optimal at the pressure of 10 atm, GHSV of 1,800 Nml g _cat^?1 h^?1, and a temperature of 503 K. Furthermore, based on the surface plot, temperature has more significant effects than the other parameters. In addition, the obtained results indicated that the maximum average number of carbon was obtained in a pressure of 10 atm and a temperature of 503 K.     

Conditions for nonhydrodewaxing reaction of hydrocracking tail oil

Hydrocracking tail oil is used in hydrogenation modification in the hydrocracking process and is an ideal material to produce lube-based oil. Through investigating the effect of operation conditions on properties of dewaxing products under atmospheric pressure, the optimum operation conditions are that reaction temperature is 360°C, volume space velocity is 1.0 h^?1, and distillation temperature is 140°C. Under the optimum condition, the yield of liquid products is higher, and the flash point, pour point, and viscosity of white oil are stable and meet the factory product requirements. Especially, properties of alkane and white oil change little when reaction time is 20 h, which indicates that HZSM-5/Al₂O₃ has better stability. When HZSM-5 molecular sieve catalyst was loaded by pseudo-boehmite, HZSM-5/Al₂O₃ catalyst activity and stability improved and became more beneficial to nonhydrodewaxing reaction of hydrocracking tail oil.     

An Orthogonal Method for Aromatization Reactions of Shenghua FCC Gasoline

Abstract

Using a confined fluidized bed reactor and aromatization catalysts (LBO-A and LBO-16), the aromatization performance of Shenghua fluid catalytic cracking (FCC) gasoline has been studied in an orthogonal method. The experimental results reveal that the optimum reaction condition for the light oil yield was reaction temperature 420°C, WHSV 40 h^?1, mass ratio catalyst to oil 4 and 75% LBO-A and 25% LBO-16; the optimum reaction condition for aromatics amount in the light oil was reaction temperature 420°C, WHSV 30 h^?1, mass ratio catalyst to oil 5 and 65% LBO-A and 35% LBO-16, the olefin content is remarkably reduced from about 54.7% to 12.8% and 8.7% (by mass), respectively, at the same time the reaction mechanism of aromatization reaction is put forward based on the experimental result.     

A Study on Modified HZSM-5 Aromatization for FCC Light Gasoline

Abstract

In this article, the HZSM-5 type zeolite catalysts modified with zinc nitrate and calcium nitrate are prepared by impregnation method. The FCC gasoline (<75°C fraction) is observed and studied on the modified HZSM-5 type zeolite catalysts. The results are that the Z _x -HZSM-5 type zeolite catalysts have a high initial aromatic yield but a rapid deactivation. The C _y -HZSM-5 type zeolite catalysts have a lower aromatic yield and a familiar deactivation comparing to Z _x -HZSM-5. The HZSM-5 type zeolite catalysts modified with bimetal zinc nitrate and calcium nitrate have a rather low initial aromatic yield but a long catalyst life; among them, the C_3.5Z_2.0HZSM-5 has the best performance. And also, the C_3.5Z_2.0HZSM-5 type zeolite catalyst has demonstrated good regenerated performance. After regenerated three times, the catalyst still has a good stability. The reaction operational conditions are also observed and studied. The results are that the optimal reaction temperature is 450–490°C, the liquid hours space velocity (LHSV) is 1 h^?1 and the reaction pressure is 0.1 MPa.     

Aromatization of FCC Gasoline Over Modified HZSM-5 Catalyst

Abstract

Zinc and phosphorus incorporated HZSM-5 catalyst was prepared by adopting incipient wet co-impregnation (Zn-P/HZSM-5). Zn-P/HZSM-5 catalyst exhibited the lowest acidity but the highest aromatization activity with stable performance in the studied period of 16 hr. The process conditions on aromatization reaction and the coke deactivation mechanism of Zn-P/HZSM-5 catalyst were studied on a small-scale, fixed bed reactor using FCC naphtha (75–120°C). The weight contents of ZnO and P₂O₅ were 2% and 4%, respectively. Results showed that Zn-P/HZSM-5 catalyst under a temperature of 450°C, liquid hourly space velocity of 1.0 h^?1, and pressure of 0.1 MPa, the conversions of olefins and alkanes are 96.77% and 88.94%, respectively, the contents of olefins, aromatics in liquid product are 6.79% and 74.57%, respectively. Carbon deposition was the major reason for catalyst deactivation due to the catalyst's good performance as a fresh catalyst after regeneration. All of the blending products fitted the standards of Chinese gasoline.     

Study on product distribution and catalytic performance of ZSM-5 in methanol conversion to gasoline-range hydrocarbons (MTHC)

Precise product distribution data is very important for kinetic modeling of chemical reactions and chemical reactor design. In this work, H-ZSM-5 catalyst was hydrothermally synthesized and characterization tests including XRD, XRF, BET, and NH₃-TPD revealed its physicochemical properties. Then, methanol conversion into hydrocarbons over ZSM-5 was investigated with WHSV of 4 h^?1 at reaction temperature 410°C. Product distribution result indicated that C₃-C₅⁺ and C₂⁼-C₄⁼ were the major products in gaseous phase, and in liquid phase xylenes, three methyl benzene and C₁₀⁺ aromatics were the main components. It was also observed that the synthesized ZSM-5 had good performance in the methanol to hydrocarbons process and gave rise to highest activity (100%) during 10 h of operation approximately.     

Thermal and catalytic pyrolysis of vacuum gas oil using HZSM-5: TG and PY-CG/MS study

The zeolite HZSM-5, was synthesized in the absence of an organic template. The characterization of zeolite HZSM-5 was performed by X-ray diffraction, N₂ adsorption/desorption isotherms and scanning electron microscopy. For catalytic tests, applying the free kinetic model, it was observed that the activation energy for the pyrolysis of pure VGO was of 82 kJ mol^?1 and for VGO/HZSM-5, the value decreased to approximately 60 kJ mol^?1, demonstrating the effectiveness of the acid sites effect of zeolite ZSM-5 for the VGO pyrolysis resulting in production of gas, gasoline and diesel.     

Desulfurization of FCC Gasoline Over Mordenite Modified with Al2O3

Abstract

Mordenite modified with Al₂O₃ (Al₂O₃/mordenite) was synthesized and used for the desulfurization of FCC gasoline. The influences of operating parameters on the results were studied for the model solution composed of dibenzothiophene (DBT) and isooctane. Al₂O₃/mordenite exhibits higher sulfur capacity than other kinds of chemisorbents. The suitable composition of the chemisorbent is 30 wt% Al₂O₃ to 70 wt% mordenite. The optimal operating parameters are: temperature 160°C; velocity 3 h^?1 (WHSV). Under the stated conditions, desulfurization was carried out for the FCC gasoline with sulfur content of 220.4 μg/g. The chemisorbent can maintain the sulfur content under 50 μg/g for 40 h and has good regeneration ability after desorption using benzene.     

One-Pot Synthesis,Crystal Structure,and Thermal Decomposition Behavior of 1,1ʹ-Diamino-4,4ʹ,5,5ʹ-Tetranitro-2,2ʹ-Biimidazole

1,1?-Diamino-4,4?,5,5?-tetranitro-2,2?-biimidazole (DATNBI) was synthesized, by employing one-pot facile method, from 4,4?,5,5?-tetranitro-2,2?-biimidazole. The crystal structure was determined by X-ray diffraction for the first time. DATNBI crystallized in monoclinic system P2₁/c, with a crystal density of 1.934 g cm^?3 at 293(2) K and 2.019 g cm^?3 at 130(2) K, respectively. Its crystal parameters at 293 K are a = 4.8833(15) Å, b = 6.960(2) Å, c = 6.928(4) Å, α = γ = 90°, β = 93.418(6)°, V = 591.1(3) ?³, Z = 2, μ = 0.178 mm^?1, and F(000) = 348. The thermal stability and non-isothermal kinetics of DATNBI were studied by differential scanning calorimeter (DSC) with heating rates of 5, 10, 15, and 20 K min^?1. The apparent activation energy (E_a) at the first decomposition peak calculated by Kissinger, Ozawa, and Starink equations were 85.50, 89.67, and 86.10 kJ mol^?1, respectively. For the second peak, these were 116.49, 119.82, and 117.45 kJ mol^?1, respectively, with individual pre-exponential factors lnA = 18.40 s^?1 and lnA = 25.11 s^?1. The thermogravimetry-Fourier transform infrared spectroscopy (TG-FTIR) analysis of thermal decomposition products reveals that the main decomposition gas products are H₂O, N₂O, CO₂, and NO₂. Based on the new crystalline densities, the detonation velocity and pressure predicted by EXPLO5 are 9062 m s^?1 and 36.4 GPa, respectively.     

Metal Promoted Mordenite Catalyst for Methanol Conversion Into Light Olefins

Methanol conversion was investigated on dealuminated mordenite (DM) as well as a series of promoted DM (i.e., metal/DM) catalysts prepared by impregnation. Prepared catalysts characterized by the powder XRD, BET, and NH₃-TPD techniques. Chemical analysis was performed using induced coupled plasma (ICP) method. The conversion of methanol over different metal/mordenite catalysts was compared at 460°C and WHSV of 1 h^?1. Several metals including Fe, La, and Ca had been used to prepare metal/DM catalysts, which displayed high selectivity toward propylene production. Ultimately, La/DM catalyst was determined to be the best material amongst those investigated for methanol conversion based upon its durability and resulting conversion.     

Influence of Aromatization Reaction Conditions in the Presence of HZSM-5 Catalyst

Abstract

The reaction conditions include temperature, weight hourly space velocity (WHSV), catalyst loading amount Ga and Si/Al, vapor, calcination temperature, soaking order, pretreatment, oxygen, and microwave heating method. The study introduces the influence of aromatization reaction conditions over HZSM-5 catalyst in detail. The proper temperature, low weight hourly space velocity (WHSV), modified HZSM-5, non-oxygen and microwave heating method are beneficial to the aromatization reaction.     

Reductive dimerization and oligomerization of alcohols,ketones, and aldehydes to hydrocarbons on a promoted,fused iron catalyst

A new reductive dimerization and oligomerization reaction of (C₅ and C₆) cycloalkanols and cycloalkanones, benzaldehyde, and benzyl alcohol to hydrocarbons containing as many, or more, carbon atoms as the reactant oxygenated compound on a promoted, fused iron catalyst proceeds at a temperature of 250–350°C, a hydrogen pressure of 0.1–1 MPa, a specific feed rate of oxygenated reagent of 80–320 g h^?1kg^?1Ct, and a hydrogen space velocity of 1 × 10³ to 20 × 10³ h^?1. Possible reaction mechanisms have been considered.     

Influence of ZnO and P2O5 Content on Modified HZSM-5 on Aromatization of FCC Gasoline

Abstract

Catalytic properties of different content of ZnO and P₂O₅ supported on HZSM-5 zeolites were studied in the conversion of FCC gasoline (75°C–120°C) into aromatic hydrocarbons with a temperature of 430°C, a liquid hourly space velocity of 1.0 hr^?1, and a pressure of 0.1 MPa. In the reaction, when the contents of ZnO and P₂O₅ are 2% and 4%, respectively, Zn-P/HZSM-5 showed the highest selectivity and activity to aromatic hydrocarbons and conversion of olefins. The content of aromatics in the liquid product and the yield of aromatics reached as high as 94.53%, 68.87%, and 51.74%, respectively.     

Modeling of Coke Formation and Catalyst Deactivation in Propane Dehydrogenation Over a Commercial Pt-Sn/γ-Al2O3 Catalyst

Propane dehydrogenation was carried over a commercial Pt-Sn/γ-Al₂O₃ catalyst at atmospheric pressure and reaction temperatures of 580, 600, and 620°C and WHSV of 11 h^?1 in an experimental tubular quartz reactor. Propane conversions were measured for catalyst time on stream of up to nine days. The amounts of coke deposited on the catalyst were measured after one, three, six, and nine days on stream using a thermogravimetric differential thermal analyzer (TG-DTA) for each reaction temperature. The coke formation kinetics was successfully described by a coke formation model based on a monolayer-multilayer mechanism. In addition, catalyst deactivation was presented by a time-dependant deactivation function. The kinetic order for monolayer coke formation was found to be two, which would support a coke formation step involving two active sites. The kinetic order for multilayer coke formation was found to be zero. The activation energy for monolayer coke formation was found to be 29.1 kJ/mol, which was lower than the activation energy of about 265.1 kJ/mol for multilayer coke formation indicating that the presence of metals can promote coke formation on the catalyst surface.     

Thermal Safety Study on TEGDN/NG/NC Gun Propellant

The self-accelerating decomposition temperature (T_SADT), critical temperature of thermal explosion (T_b), adiabatic time to explosion (t_TIad), 50% drop height of impact sensitivity (H₅₀), critical temperature of hot spot initiation caused by impact (T_cr,hotspot), safety degree (S_d), critical thermal explosion ambient temperature (T_acr), and thermal explosion probability (P_TE) of the gun propellant composed of triethyleneglycol dinitrate (TEGDN), nitroglycerin (NG), and nitrocellulose (NC) were studied. The results of thermal safety evaluation on the gun propellant were obtained: (1) T₀₀ = 433.4 K, T_SADT = T_e0 = 441.1 K, T_b = T_bp0 = 468.4 K; (2) when E_k = 205.3 × 10³ J mol ^?1 and A_k = 10^20.62 s ^?1, t_TIad = 48.3 s, H₅₀ = 17.93 cm, T_{cr, hotspot} = 634.9 K; for a sphere sample, T_S(T)max  = 369.0K, T_acr = 364.2 K, S_d = 65.03%, P_TE = 34.96%.     

Kinetic Modeling of the Catalytical Reaction of Syngas to Light Olefins

Nowadays converting synthesis gas to makes olefins is an important issue and researcher has been focused on it. The kinetic experiments for synthesis gas reactions over RIPI-Co/Mn catalyst to light olefin are carried out in a micro-fixed-bed reactor under the following conditions: temperature 220–300°C, pressure 1–5 atm, H₂/CO feed ratio 1–3, and space velocity of 450-600 h^?1. In order to obtain the parameters of the kinetic model, the optimum values of the kinetic parameters have been obtained. The global minimum for the optimized function has been achieved, with using the genetic algorithm. The data of this study were best fitted by a Langmuir-Hinshelwood (LH) rate form R_co = kP_coP_H2^1/2/ (1+aP_co+bP_H2^1/2)².     

FCC Gasoline Hydroisomerization Over Pt/HZSM-5 Catalysts

Abstract

Pt/HZSM-5 bifunctional catalyst of fluid catalytic cracking (FCC) gasoline hydroisomerization was prepared. The influence of calcinations and reduction conditions, the metal-incorporation technique, and metal loading on the hydroisomerization of FCC gasoline over the Pt/HZSM-5 bifunctional catalyst was studied. The process opinion catalyst of FCC gasoline hydroisomerization was obtained under the condition of temperature 290–300°C; pressure 1.5–2.5 Mpa; liquid hour space velocity (LHSV) 2.0–3.0 hr^?1; V(H₂)/V(Oil) = 2.0–3.0. The results showed that calcination conditions have a significant influence on ion-exchanged catalysts, as they control the final metal distribution. The reduction conditions and the method used for platinum incorporation were found to be important factors that affected both the activity and selectivity of the catalysts. Pt/HZSM-5 bifunctional catalyst possessed good activity for hydrogenation and isomerization. The olefin hydrocarbons of FCC gasoline were hydrogenated and the stability of FCC gasoline was improved under condition of unchanged octane number.     

RESIDUUM HYDROTREATING APPLICATION OF IH AND QUANTITATIVE CARBON-13 NMR SPECTROSCOPY FOR THE STUDY OF HYDROTREATED PRODUCTS

ABSTRACT

Bai-Hassan reduced crude (350^°C + ) was hydrotreated in fixed bed reactor with commercial Ni-Mo-alumina catalyst. H and quantitative C NMR are used to derive statistical average structure parameters of feedstock and hydrotreated products. The main aromatic hydrocarbons (of type C_ar,H + C_ar,CH₃ + C_ar,n + C_ar,I) of hydrotreated products decreases by temperature, (at mild conditions) particularly at lower space velocity. The severe operating conditions increases the main aromatic hydrocarbons. An approximate inverse correlation is observed between the behaviour of saturated hydrocarbons and the aromatics of type C_ar,H + C_ar,CH₃ + C_ar,n + C_ar,I during hydrotreating process. Higher temperatures show an increase in the percentage of alkyl aromatics of type C_ar,alkFurthermore, the severe operating conditions promotes the formation of the alkyl aromatics with H_α(ArCH₃) while it decreases the alkyl aromatic having H₈ and H₈ The kinetic study of napthenes formation indicates that this reactin is well correlated with a first-order kinetics. The apparent activation energy lpar;E rpar;, enthalpy lpar;? H rpar;and entropy lpar;? s?lpar; of activation are 23.630 KJ mol 18.390 kJ mol ^-1 and -225.95 J mol^-1 k^-1 respectively.