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2021 ◽  
Author(s):  
◽  
Emmanuel Zikhonjwa

The performance of Ni/HZSM-5, HZSM-5, and without a catalyst have been investigated for the hydrogen pressure range of 10-40bar hydrocracking of coconut oil in a packed-bed tubular reactor between 300-450°C. This study concentrates on the effect of the operating parameters (reaction pressure, type of catalyst and reaction temperature) on the yield of transportation fuel carbon range (C5-C22) using the One-Variable-At-A-Time approach. The objectives of this study are to evaluate the effect of process conditions which includes: temperature, pressure, and presence of a catalyst, and to compare the activity of Ni/HZSM-5, HZSM-5 and without catalysts. All tested catalysts were effective in attaining biofuel range in the liquid product. The highest yield and performance of gasoline liquid composition 83.03% was obtained from the reaction pressure at constant temperature of 450 ͦC in 40bar where HZSM-5 catalysts was used, the yield of gasoline liquid composition 82.25% was also produced at constant pressure of 40 bar in 300 ͦC where promoted catalyst(Ni/HZSM-5) was used. Hydrocracking coconut oil under Ni/HZSM-5 catalysts produced the highest yield of jet fuel liquid compositions 78.73% at constant temperature 300°C, and pressure of 10 bar, this was due to less coke that was formed within a reactor and less temperature of 300°C. The highest yield of jet fuel liquid composition 75.67% was also produced at constant pressure of 10 bar at muximum temperature of 450 ͦ C, this was also due to less coke that was formed within a reactor where HZSM-5 was used because of less pressure applied. For the highest yield of diesel liquid composition 24.04%, constant temperature at 400 ͦC of 20 bar where Ni/HZSM-5 was used in figure:5-9 and the highest yield of diesel liquid composition 25.15% was also produced at constant pressure of 20 bar in 450 ͦC where HZSM-5 was used. X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM) coupled with Energy- dispersive X-ray spectroscopy (EDS) analyses were employed for catalyst characterization. XRD patterns confirm the success of metal doping on ZSM-5. Major peaks at 9.1° and 22.9° corresponding to ZSM-5 crystals were observed in ZSM-5. Impregnation with metals reduced the crystallinity of ZSM-5 supported catalysts.


Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6602
Author(s):  
Lili Qian ◽  
Jun Ni ◽  
Zhiyang Xu ◽  
Bin Yu ◽  
Shuang Wang ◽  
...  

Hydrothermal liquefaction can directly and efficiently convert wet biomass into biocrude with a high heating value. We developed a continuous hydrothermal liquefaction model via Aspen Plus to explore the effects of moisture content of Chlorella, reaction pressure and temperature on thermodynamic equilibrium yields, and energy recoveries of biocrude. We also compared the simulated biocrude yield and energy recoveries with experiment values in literature. Furthermore, vertical and horizontal transportation characteristics of insoluble solids in Chlorella were analyzed to determine the critical diameters that could avoid the plugging of the reactor at different flow rates. The results showed that the optimum moisture content, reaction pressure, and reaction temperature were 70–90 wt%, 20 MPa, and 250–350 °C, respectively. At a thermodynamic equilibrium state, the yield and the energy recovery of biocrude could be higher than 56 wt% and 96%, respectively. When the capacity of the hydrothermal liquefaction system changed from 100 to 1000 kg·h−1, the critical diameter of the reactor increased from 9 to 25 mm.


2021 ◽  
Vol 1195 (1) ◽  
pp. 012034
Author(s):  
M K Koh ◽  
Y J Wong ◽  
A R Mohamed

Abstract The direct CO2 hydrogenation to methanol is an attractive route to actively remove CO2 and to promote sustainable development. Herein, the performance of Cu-Zn-Mn catalyst supported on mesoporous silica KIT-6 (hereafter, CZM/KIT-6) for methanol synthesis by direct CO2 hydrogenation reaction was investigated by varying the process parameters, which included the weight-hourly space velocity, reaction temperature and reaction pressure. The CO2 conversion was found to decrease with the increase of WHSV. On the other hand, CO2 conversion increased with reaction temperature and pressure. Meanwhile, the methanol selectivity increased with WHSV and reaction pressure but decreased with the increase of reaction temperature. The apparent activation energy of methanol production at low reaction temperature (160 - 220 °C) was 10 kcal/mol. Non-Arrhenius behaviour of methanol formation was observed at high reaction temperature (220 - 260 °C). The performance of CZM/KIT-6 was maintained at high level, with the average methanol yield of 24.4 %, throughout the stability experiment (120-hour time-on-stream). In post-reaction XRD analysis, the copper crystallite growth was found to be 53.5 %, thus, resulting in 35.3 % loss of copper surface area.


2021 ◽  
Vol 9 ◽  
Author(s):  
Le Tong ◽  
Bo Cai ◽  
Ronghua Zhang ◽  
Junfeng Feng ◽  
Hui Pan

Nb2O5-supported bimetallic catalysts were prepared by the impregnation method applied for the in situ hydrogenation of guaiacol. Guaiacol can be effectively transformed into cyclohexanol over different bimetallic catalysts using alcohol as the hydrogen donor. Meanwhile, the effects of different hydrogen donors such as isopropanol, sec-pentanol, and ethylene glycol on in situ hydrogenation of guaiacol were investigated in detail, and the results showed that isopropanol is the best hydrogen supply solvent. Then, the dependence of Ni–Mn/Nb2O5 properties on metal loading, reaction time, reaction temperature, and reaction pressure was studied for the in situ hydrogenation of guaiacol by using isopropanol as the hydrogen donor. Guaiacol can be completely converted, and the yield of cyclohexanol reached 71.8% over Ni–Mn/Nb2O5 with isopropanol as the hydrogen donor at 200°C for 5 h. The structures and characteristics of better catalytic properties of the Ni–Mn/Nb2O5 catalyst were determined by BET, NH3-TPD, XRD, XPS, SEM, and TEM, and the results indicated the particle size of the metal was small (approximately 10 nm) and the metal particles are finely dispersed in the whole support. Therefore, a large number of medium acid sites were generated on the 10Ni-10Mn/Nb2O5 with a large specific surface area, which could increase the interface between the metal and the support and may be beneficial to the hydrodeoxygenation of guaiacol.


2021 ◽  
pp. 1-9
Author(s):  
Jian-bin Zhang ◽  
Huan-huan He ◽  
Hai-Feng Tian ◽  
Jian-Kang Liao ◽  
Fei Zha ◽  
...  

The ZnIn/HZSM-5 catalyst was prepared by the wetness impregnation method, and the structure of catalyst was characterized by XRD, SEM, TEM, H2-TPR, NH3-TPD, XPS, TG, and N2 adsorption–desorption and then investigated in the coupling of propane with CO2 to propylene. It is found that the addition of Zn species is beneficial to the dispersion of In2O3 over HZSM-5, which plays an important role in propene formation, and adjusts the acidity distribution of In/HZSM-5 catalyst, as well as significantly improves the activity of In/HZSM-5 catalyst. The selectivity of propylene is 68.21% in the coupling of propane with CO2 over ZnIn/HZSM-5 catalyst when the time on stream (TOS) is 2 h, reaction temperature is 580 °C, reaction pressure is 0.3 MPa, C3H6:CO2:N2 = 1:4:5, catalyst mass is 0.2 g, and space velocity is 6000 mL gcat−1 h−1. However, the selectivity of propylene is only 63.33% and 0.25% in the propane dehydrogenation or CO2 hydrogenation reaction, respectively. The ZnIn/HZSM-5 catalyst showed a higher stability with only 0.80% conversion drop after three cycles.


2021 ◽  
Author(s):  
Shanta Dutta ◽  
Iris K. M. Yu ◽  
Jiajun Fan ◽  
James H. Clark ◽  
Daniel C. W. Tsang

This study provides new and critical insights into sustainable catalytic conversion of food (bread) waste to platform chemicals for achieving sustainable development goals and fostering a circular economy.


Author(s):  
Tiezhen Zhang ◽  
◽  
Yungang Jia ◽  
Famin Sun ◽  
Liang Wang ◽  
...  

A reforming prehydrogenation catalyst suitable for blending inferior coking gasoline was developed by the supporter modification, selection and optimization of active component. The catalyst has high performance of hydrodesulfurization, hydrodenitrification and olefin saturation at low temperature. The catalyst has good activity and strong adaptability to raw materials, At reaction pressure of 2.0MPa, hydrogen-oil volume ratio of 200:1, LHSV of 5.0h-1, reaction temperature of 268-280℃, it can process the prehydrogenation raw materials blending inferior hydrocoking gasoline (20-50%), and the generated oil can meet the requirements of reforming feed. The results of 1500h activity stability test show that the catalyst has excellent activity stability.


2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Aihua Zhang ◽  
Juan Tang ◽  
Jilie Lie ◽  
Yidan He ◽  
Zhihong Xiao

The Ni-ZSM-5 catalyst, under four different factors of Swida wilsoniana pyrolysis products of catalytic hydrogenation, GC-MS, FI-IR, and elemental analyzers, was used to identify the elements, carbon chain distribution, and composition of the products. The effects of reaction temperature, reaction pressure, and catalyst hydrogenation level on the conversion rate were investigated. The reaction pressure and the amount of catalyst are the main factors that affect the conversion of the pyrolysis products into biofuels. Using 1.05 wt.% Ni-ZSM-5 catalyst, the highest conversion rate was 98.10% at 173°C and 2.00 MPa. The results show that Swida wilsoniana-decomposed products can be converted to high-quality biofuels by catalytic hydrogenation of Ni-ZSM-5 and can be used as an alternative energy source.


2020 ◽  
Vol 351 ◽  
pp. 50-57 ◽  
Author(s):  
Jianqiao Wang ◽  
Boxiong Shen ◽  
Meichen Lan ◽  
Dongrui Kang ◽  
Chunfei Wu

2020 ◽  
Vol 142 (12) ◽  
Author(s):  
Naveen Kumar ◽  
Ankit Sonthalia ◽  
Rashi Koul

Abstract Hydrotreating process is an alternate approach for producing diesel hydrocarbons from the biomass-based oils. In the present study, used cooking oil was selected for the hydrotreating process due to its high abundance. A batch reactor was used for carrying out the experiments. To increase the reaction rate a manganese, cerium promoted ruthenium-based catalyst supported on Al2O3 was used. The design of experiments was used for optimizing the process parameters. The Taguchi method was selected as it reduces the number of experiments which saves time and money. The study was aimed at increasing the conversion percentage and diesel selectivity and reducing the naphtha selectivity. Since multi-objective optimization was required, fuzzy logic was incorporated which utilizes the human thought logic. The analysis of variance shows that the reaction temperature and reaction pressure significantly affect the output parameters. Higher temperature leads to cracking of the oil resulting in the formation of large amount of lower carbon chains. Moreover, high hydrogen pressure results in increase in the hydrogenation process, thereby increasing the diesel selectivity. The optimized parameters obtained from the study were 360 °C reaction temperature, 40-bar initial reaction pressure, and 200-min reaction time. Confirmation experiment was carried out using these parameters, and the conversion efficiency and diesel selectivity was 89.7% and 88.2%, respectively. The study shows that the combination of Taguchi and fuzzy logic is an effective method for optimizing the process parameters of the hydrotreating process.


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