Table of Content

12 November 2024, Volume 55 Issue 11

Previous Issue    Next Issue

HYDROGENATION OF 5-HYDROXYMETHYLFURFURAL TO 2,5-BIS(HYDROXYMETHYL)FURAN ON Au/Al₂O₃ CATALYST

2024, 55(11):  1-10. 

Asbtract ( 259 )   PDF  

References | Related Articles | Metrics

In order to explore the high efficiency catalyst for the hydrogenation of biomass aldehyde, the Au/Al₂O₃ catalyst was prepared by precipitation and deposition method with noble metal Au as the active component. The morphology of the catalyst was characterized by X-ray powder diffractometer, transmission electron microscopy, X-ray photoelectron spectroscopy, static low temperature nitrogen adsorption capacity method and NH₃ programmed temperature desorption. The Au/Al₂O₃ catalyst was applied to the hydrogenation of 5-hydroxymethylfurfural (HMF) to 2,5-bis(hydroxymethyl)furan (BHMF). The effects of precipitator type, Au loading capacity, reaction temperature, reaction pressure and reaction time on the catalytic performance were investigated, and the cyclic stability of the catalyst was analyzed. The results showed that the active metal Au had a high catalytic activity for the reaction, and the type of precipitator had a significant effect on the particle size and loading rate of Au particles, leading to a certain difference in activity. When the precipitant was a mixture of NaOH and Na₂CO₃ (mass ratio of 1:1), the Au loading capacity was 2.0%, the reaction temperature was 100 ℃, the H₂ pressure was 3.0 MPa, and the reaction time was 4 h, 0.30 g catalyst could catalyze 2.4 mmol HMF to BHMF. The mass conversion of HMF was 92.1% and the mass selectivity of BHMF was 92.0%.

EFFECT OF Cr ON DENITRATION PERFORMANCE OF V₂O₅-WO₃/TiO₂ CATALYST

2024, 55(11):  11-16. 

Asbtract ( 110 )   PDF  

References | Related Articles | Metrics

The V₂O₅-WO₃/TiO₂ type catalyst was covered with a layer of black substance after 2 years of operation in a petrochemical company. The composition of the black matter was determined, and the effect of black matter on the denitration performance of catalyst was studied. The mass fraction of Cr element on the surface of the catalyst was about 12% by energy spectrum analysis, and the main composition of Cr element was Cr₂O₃ by X-ray diffraction. The overall denitrification performance of the catalyst was inferior to that of fresh catalyst, especially at higher temperatures. The results indicated that the decrease of catalyst performance was probably related to the reduction of V⁴⁺ content on the catalyst surface and the decrease of catalyst reduction performance. In conclusion, Cr element has a significant impact on V₂O₅-WO₃/TiO₂ catalyst, so the content of Cr in the flue gas should be reduced as far as possible, and the flue gas temperature should be controlled to around 350 ℃ to reduce the influence of Cr.

INDIUM-DOPED MoVTeNbOx CATALYST FOR SELECTIVE OXIDATION OF PROPANE TO ACRYLIC ACID

2024, 55(11):  17-24. 

Asbtract ( 86 )   PDF  

References | Related Articles | Metrics

Indium-doped MoVTeNbO_x catalyst (Mo_1.00V_0.30Te_0.23Nb_0.12InyO_x) for the selective oxidation of propane to acrylic acid was prepared by the coprecipitation method. Compared with the MoVTeNbO_x catalyst without In-doping, the yield of acrylic acid on the above-mentioned catalyst was significantly increased. Indium-doped catalysts were characterized by X-ray diffraction, H₂ temperature-programmed reduction, scanning transmission electron microscopy and X-ray photoelectron spectroscopy. The results showed that proper amount of Indium-doping could effectively increase the content of Mo⁶⁺, V⁵⁺ and Te⁴⁺ on the surface of the catalyst, thereby influencing the activity of the catalyst and the selectivity of acrylic acid. The optimal range of y was 0.025 to 0.04. Indium-doping in this range helped to adjust the number of acid sites on the surface of the catalyst and improve the oxidation of the catalyst. Under the conditions of the reaction temperature of 400 ℃, the space velocity of 1 000 mL/(g·h), the n(C₃H₈): n(O₂): n(H₂O) equaling to 1:2:12 and the molar ratio In/Mo of 0.025, the conversion of propane was 67.99%, the selectivity of acrylic acid was 58.30%, and the yield of acrylic acid was 39.64%.

ANALYSIS ON THE DEACTIVATION REASON OF CATALYTIC CRACKING CATALYST IN A PETROCHEMICAL PLANT

2024, 55(11):  25-30. 

Asbtract ( 138 )   PDF  

References | Related Articles | Metrics

The deactivation of catalytic cracking catalyst is one of the important factors that affect the product quality and economic benefit of catalytic cracking units. The analysis of the reasons for the catalyst deactivation is of great theoretical significance to slow down or restrain the catalyst deactivation. In the present work, the deactivated catalytic cracking catalyst in a petrochemical plant was characterized by N2 physical adsorption, XRD, pyridine adsorption infrared (Py-IR) and X-ray fluorescence (XRF). The results showed that the structure of the molecular sieve in the deactivated catalyst collapsed seriously, the surface area decreased greatly, and the acid center decreased sharply. A large amount of V, Ni, Ca and other elements deposited on the deactivated catalyst. The continuous regeneration of the catalyst made the catalyst constantly subject to high temperature hydrothermal process, which could be one of the main factors of molecular sieve structure collapse. Secondly, the deposition of V, Ni and Ca could reacts with the molecular sieve and alumina on the catalyst at high temperatures, which was another reason for the catalyst structure damage. In addition, the deposition of metals also could poison the acid sites on the catalyst. These factors led to a significant decrease in catalyst acidity and to a permanent deactivation of the catalyst.

PREPARATION OF TiO₂ AND ZrO₂ AND THEIR ADSORPTION PERFORMANCE FOR PYRIDINE

2024, 55(11):  31-39. 

Asbtract ( 71 )   PDF  

Related Articles | Metrics

Anatase TiO₂ and cubic ZrO₂ were prepared by hydrothermal-corrosion method or sol-gel method, respectively, and characterized by X-ray diffraction, N₂ adsorption-desorption and FT-IR and SEM. Using TiO₂ and ZrO₂ as adsorbents and n-dodecane containing pyridine as simulated diesel fuel, the effects of TiO₂ and ZrO₂ dosage, adsorption time and adsorption temperature on the adsorption and denitrification of simulated diesel fuel were investigated. The results showed that the adsorption of pyridine on TiO₂ and ZrO₂ could reach the adsorption equilibrium in a short time, and the adsorption process conformed to the quasi-primary and secondary kinetic equations. The temperature has no obvious effect on the adsorption of pyridine by TiO₂ and ZrO₂, and the adsorption of pyridine by TiO₂ and ZrO₂ is the coexistence of single-layer adsorption and multi-layer adsorption. The adsorption configurations and adsorption energy of pyridine on the TiO₂(101) and ZrO₂(111) crystal surfaces were studied by simulation method. Pyridine can form N—Ti and N—Zr chemical bonds on the crystal surfaces of TiO₂(101) and ZrO₂(111), and the corresponding adsorption energies of pyridine are -188.59kJ/mol and -157.34 kJ/mol, respectively. The results indicated that pyridine could be stably adsorbed on the TiO₂(101) and ZrO₂(111) crystal surfaces.

COMMERCIAL APPLICATION OF NOVEL CATALYTIC CRACKING ADDITIVE HBC-B FOR BOOSTING BUTYLENE YIELD

2024, 55(11):  40-46. 

Asbtract ( 120 )   PDF  

References | Related Articles | Metrics

A new catalytic cracking additive HBC-B for boosting butylene yield was developed by SINOPEC Research Institute of Petroleum Processing Co., Ltd., and the commercial application was carried out on the maximizing catalytic propylene from heavy oil (MCP) unit of Yangzhou Petrochemical Co., Ltd.. The results showed that butylene yield increased by 1.47 percentage points, isobutylene yield increased by 0.34 percentage point, and the volume fraction of butylene in liquefied petroleum gas (LPG) increased by 4.05 percentage points when HBC-B additive accounts for 5.0% of the catalyst inventory in the system. The product distribution was improved, the yield of LPG increased by 0.55 percentage point, the yield of gasoline increased by 0.71 percentage point, and the yield of light cycle oil decreased by 1.28 percentage points, the yields of slurry and coke were basically the same. The commercial application results showed that HBC-B additive had excellent butylene selectivity and heavy oil cracking ability.

PREPARATION OF ZSM-5 WITH HIERARCHICAL PORES BY ALKALI TREATMENT AND Fe-MODIFIED AND ITS CATALYTIC PERFORMANCE FOR SYNTHESIS OF DIPHENYLMETHANE

2024, 55(11):  47-53. 

Asbtract ( 100 )   PDF  

Related Articles | Metrics

Fe-ZSM-5 molecular sieve with hierarchical pore structure was prepared by alkali treatment of ZSM-5 and impregnation method. The catalyst samples were characterized by X-ray diffraction, N2 adsorption-desorption and NH3 temperature programmed desorption. The results showed that the pore size of the zeolite was enlarged, the amount of weak acid sites increased significantly, the strength of weak acid became stronger, and the amount of strong acid sites decreased when ZSM-5 was treated with 0.05 mol/L of sodium hydroxide solution. After loading Fe, the structure of ZSM-5 was still maintained. The alkylation of benzene with benzyl chloride was carried out to investigate the effects of alkali concentration, metal loading, calcination time and temperature on the catalytic performance of the catalyst for the synthesis of diphenylmethane. The experimental results indicated the prepared catalyst had the high catalytic performance for the alkylation reaction when the Fe to molecular sieve mass ratio was 5%, the sodium hydroxide concentration was 0.05 mol/L, the alkali treatment time was 30 minutes, the calcination temperature was 450 ℃, and the calcination time was 4 h. The conversion rate of benzyl chloride was 96.2%, and the selectivity of diphenylmethane was 84.9%.

PRODUCTION TECHNOLOGY OF LIQUID WAX AND BASE WAX FROM FISCHER-TROPSCH SYNTHETIC OIL

2024, 55(11):  54-59. 

Asbtract ( 130 )   PDF  

Related Articles | Metrics

Based on Fischer-Tropsch synthetic oil, the technologies of deep deoxygenation and molecular sieve dewaxing for producing liquid wax and base wax were developed. The newly developed hydrofinishing catalyst has high deoxidizing activity. Under medium pressure and relatively mild process conditions, the product obtained from the hydrofining of Fischer-Tropsch synthetic oil has the oxygen content of less than 5.0 μg/g and the chromaticity (Cyberport) of more than ＋30. The middle fraction can be used as a feedstock for liquid wax, and the tail oil fraction can be used as a feedstock for base wax. The results of molecular sieve dewaxing test showed that the mass fraction of n-alkanes in the separated light liquid wax was 99.25%, which was higher than the lower limit (98.5%) specified in GB/T 32066—2015; the mass fraction of n-alkanes in the separated heavy liquid wax was 99.44%, which was much higher than the lower limit (95%) specified in GB/T 32066—2015.

EFFECT OF ELECTRIC FIELD PARAMETERS ON RHEOLOGICAL CHARACTERISTICS OF HEAVY OIL EMULSION

2024, 55(11):  60-67. 

Asbtract ( 107 )   PDF  

References | Related Articles | Metrics

The electrorheological characteristics of heavy oil emulsion in an oilfield were experimentally studied by using an electrorheometer. Taking the viscosity reduction rate as the evaluation index, the influence of electric field parameters (electric field strength, electric field frequency, etc.) and non-electric field parameters (temperature, shearing rate, etc.) on the rheological characteristics of heavy oil was systematically and comprehensively explored under the action of high-frequency/high-voltage pulsed AC electric field. The orthogonal experimental design method was used to compare the influence of electric field parameters and non-electric field parameters on the rheological characteristics of heavy oil. The results showed that among the electric field parameters, the electric field strength had the greatest influence, followed by electric field frequency and duty cycle; among the non-electric field parameters, temperature had the greatest influence, followed by water content and shear rate. In addition, the electrorheological experiment of sand-containing heavy oil emulsion was carried out, and the optimal electric field strength and electric field frequency values obtained were similar to those of sand-free heavy oil emulsion.

QUANTUM CHEMISTRY STUDY OF ELECTRONIC STRUCTURE AND SPECTRAL PROPERTIES OF PETROPORPHYRINS

2024, 55(11):  68-73. 

Asbtract ( 78 )   PDF  

Related Articles | Metrics

Petroporphyrins are usually porphyrins-coordinated nickel/vanadium compounds. The types and forms of petroporphyrins are very complex. In this work, the geometry structure, electronic structure and spectral properties of of Ni²⁺ and VO²⁺ primary porphyrin (ETIO) type compounds were calculated by using PBE density functional, and the simulated results were in line with experimental results. The ETIO porphyrin ring is coordinated with Ni²⁺ or VO²⁺ via four nitrogen atoms to form molecules with D_4H symmetry and C_4V symmetry, respectively. The V-N bond is weaker than Ni-N bond because of the competition of axial coordination O atoms, therefore, V is more subject to hydrodemetallization (HDM) than Ni during residue hydrotreating. The electronic structure of Ni²⁺/VO²⁺-porphyrin compounds was analyzed. The resuts showed that the porphyrin ring had a remarkable conjugation effect, and the conjugated π orbitals were formed by the porphyrin ring overlaps with the 3d orbitals of Ni or V. Therefore, the interaction between porphyrin and Ni or V is very strong. The valence electron transitions of Ni²⁺-ETIO and VO²⁺-ETIO compounds were calculated by using time-dependent density functional theory (TDDFT), and the characteristic UV-Vis absorption was obtained. The Soret band with strong absorption and the Q band with weak absorption were calculated theoretically, which was consistent with the spectral characteristics reported in literature. These characteristic absorption in UV-Vis spectrum was explained theoretically.

NUMERICAL SIMULATION AND STRUCTURAL OPTIMIZATION OF NOVEL COALESCER IN OIL-WATER SEPARATOR

2024, 55(11):  74-83. 

Asbtract ( 85 )   PDF  

Related Articles | Metrics

In order to solve the problem of poor separation efficiency of traditional plate-type coalescer structures, a novel type of coalescer with outlet baffles was proposed, and a computational fluid dynamics (CFD) method was used. The effects of the bonding plate length (l), the inclined angle (θ), the baffle height (h) and the baffle angle (α) on the separation performance of the novel coalescer were investigated by mixture model of Fluent code and standard k-? model, and the optimal structural parameters were determined. The results showed that the coalescer had a significant effect on the separation effect of the oil-water separator; under the same conditions, the separation efficiency of the coalescer with outlet baffles was 1.2% higher than that without outlet baffles. For the four structural parameters, the separation efficiency of the separator with outlet baffles showed a trend of first increasing and then decreasing with the increase of a single structural parameter, and the optimal value was l/L=3/12 (L is the length of separator), θ=30°, h/H=7/10 (H is the spacing of baffle) and α=75°; the optimal combination of four kinds of structural parameters obtained by response surface analysis was l=421.67 mm, θ=45.07°, h=8.84 mm and α=112.70°. The separation efficiency of the separator with outlet baffles was 97.67%.

EFFECT OF ASH-BUCKET COKE TRAP ON SEPARATION PERFORMANCE AND FLOW FIELD OF CYCLONE SEPARATOR IN FCC UNIT

2024, 55(11):  84-89. 

Asbtract ( 71 )   PDF  

References | Related Articles | Metrics

It is one of the most important hidden troubles to threaten the long-term stable operation of catalytic cracking unit that the coke blocks on the outer wall of the vortex finder of the cyclone separator on the top of the settler (top-cyclone). To solve this problem, a new prevention and cure scheme was put forward, which was to set up a network coke trap in the ash bucket of the top cyclone to intercept the large coke falling off and avoid the clogging of the dipleg. The separation efficiency, pressure drop and flow field changes of the cyclone separator with different structures of the ash bucket were investigated in a comparative study with the methods of experiment and numerical simulation. The results showed that the pressure drop of the cyclone separator was not obvious, but the separation efficiency dropped about 0.21~0.91 percentage point after adding coke trap and intercepting coke block in the ash bucket. The maximum tangential velocity of the fluid in the separation space and ash bucket decreased by 0.4% and 41.2%, respectively. At the same time, the upward region of the axial inner swirl increased, resulting in the increase of particle entailing, the increase of particle backmixing escape rate and the decrease of separation efficiency. Increasing the height of the ash bucket can reduce the escape rate and entrainment of particles, restore or even improve the separation efficiency. So, it can be realized to prevent and control the hidden danger of coke blocking the dipleg by installing a coke trap and increasing the height of ash bucket.

STUDY ON THE CHARACTERISTICS OF COLUMNAR GRANULAR BED IN TUBULAR FIXED BED REACTOR BASED ON CFD-DEM METHOD AND POROUS MEDIUM MODEL

2024, 55(11):  90-99. 

Asbtract ( 135 )   PDF  

References | Related Articles | Metrics

The computational fluid dynamics and discrete element method (CFD-DEM) and the porous medium model were used to numerically simulate a tubular fixed-bed reactor, and the packing characteristics and unit pressure drop of the column particle bed were compared. The consistency and efficiency of the two numerical simulation methods were compared. The calculation results showed that the column bed was more stable with mixed loading than with single loading. In the single loading and a certain tube diameter ratio, the pressure drop of bed increased with the increase of the inlet gas velocity when a single filling was used and the pipe diameter ratio was fixed. Therefore suitable inlet gas velocity should be selected in practical applications to prevent equipment damage. When the hybrid loading method was used, the bed cross-section pressure fluctuation was significantly reduced by 20.63%, and the bed particle accumulation was more uniform. Comparing the calculation results and efficiency of CFD-DEM with that of porous media model, it was found that when the particle Reyno number (Re_p) was less than 229, the maximum deviation of bed pressure drop between the porous media model and the coupling algorithm was 6.3%; when the Re_p increased from 229 to 458, the deviation of bed pressure drop increased with the increase of Re_p, and the maximum deviation was 13.4%, which met the requirement of engineering accuracy. In terms of computational efficiency, the calculation time of porous media model is 1/320 of that of CFD-DEM coupling algorithm. Therefore, the porous media model has better applicability and reliability for the calculation of columnar granular beds when the pipe diameter ratio is greater than 16.58 and Rep is less than 458.

ANALYSIS AND SOLUTION MEASURES OF EXCESSIVE SO2 CONCENTRATION IN FLUE GAS OF HEATING FURNACE DURING THE PRESULFIDING PERIOD OF HYDROTREATING UNIT

2024, 55(11):  100-105. 

Asbtract ( 64 )   PDF  

Related Articles | Metrics

During the presulfiding period of the hydrotreating unit, the SO₂ concentration in the flue gas of the heating furnace has increased abnormally or even exceeded the standard, and enterprise was forced to stop the recovery of torch gas. By analyzing the sulfur types and content of circulating hydrogen, low separation gas and flare gas during the start-up of presulfiding period, it is speculated that the methyl mercaptan and methyl sulfide produced by the step-by-step decomposition of the sulfurizing agent enter the fuel gas system with the flare gas. The SO₂ produced by the combustion of methyl mercaptan and methyl sulfide causes the concentration of SO₂ in the flue gas of the heating furnace to exceed the standard. This problem can be solved by optimizing the desulfurization solvent of torch gas, using ex-situ true sulfidization catalyst and using new sulfiding agents.

EFFECT ANALYSIS OF CATALYTIC OZONATION TECHNOLOGY IN UPGRADING TREATMENT OF WASTEWATER FROM REFINERIES

2024, 55(11):  106-110. 

Asbtract ( 75 )   PDF  

References | Related Articles | Metrics

Analysis and evaluation of catalytic ozonation technology in the third-stage (deep) treatment of wastewater is of great significance to the selection of wastewater quality improvement technology in refining and chemical enterprises. Through on-site investigation, operational water quality data collection and sampling analysis of two typical heterogeneous catalytic ozonation units for oily and saline wastewater in industrial operation, the results of statistics and analysis of chemical oxygen demand (COD) in inlet and outlet water showed that the catalytic ozonation had a certain effect on the removal of COD in oily and saline wastewater, but the deactivation of the catalyst was faster. After a period of operation, the average removal concentration of COD was only about 10 mg/L, which was similar to that of non-catalytic ozonation and had little effect on improving biological oxygen demand (BOD5).

ALCULATION AND EVALUATION OF CARBON FOOTPRINT IN LUBE BASE OIL PRODUCTION STAGE

2024, 55(11):  111-118. 

Asbtract ( 97 )   PDF  

Related Articles | Metrics

The demand for lube base oils is growing steadily. Under the background of carbon peaking and carbon neutrality goals, carbon footprint assessment has become a new way to promote the green transformation of industry. Based on the basic principles of accounting standard PAS 2050 developed by the British Standards Institute, the key accounting parameters were adaptively optimized, and the carbon footprint accounting method in line with the actual production of domestic lube base oil was established. Taking the lube base oil products of an enterprise as the evaluation object, the carbon footprint of its production stage was calculated, the emission impact assessment was carried out on the production process, unit devices and emission sources, etc., and targeted emission reduction measures and suggestions were put forward. The results showed that the carbon footprints (calculated in carbon dioxide equivalent) of the old three processes, hydrogenation and isomerization dewaxing were 437.9, 372.4 and 494.4 kg/t,respectively. Hydrocracking and lube oil hydrogenation units are the key devices to reduce emissions, and steam, electricity, fuel gas and circulating water are the key emission sources. Based on this, The emission reduction suggestions were put forward from the aspects of accelerating the substitution of new energy, improving device energy efficiency, strengthening carbon emission factor monitoring and optimizing public engineering systems to help enterprises achieve high performance.

STUDY ON THE EFFICIENT ABSORPTION OF H2S BY A NON-AQUEOUS WET OXIDATION DESULFURIZER CONTAINING IRON AND ANTIMONY

2024, 55(11):  119-125. 

Asbtract ( 66 )   PDF  

References | Related Articles | Metrics

A non-aqueous wet oxidation desulfurization system was constructed by introducing SbCl₃ and FeCl₃ into N,N-dimethylformamide (DMF) at a certain ratio. The desulfurizer and its products were characterized, and the absorption rule of this system for H₂S was studied by static desulfurization experiment. The results showed that the sulfur capacity of the desulfurizer could reach 8.91 g/L at normal temperature and pressure, and the addition of an appropriate amount of water and proper heating would facilitate the enhancement of the desulfurization efficiency. After five consecutive desulfurization-regeneration cycles, the sulfur capacity was kept above 90% of the initial sulfur capacity in the presence of Cu²⁺. XRD spectra indicated that the solid product after regeneration was high-purity sulfur. Sb³⁺ was a key component to ensure the effective absorption of H₂S. The presence of a suitable amount of Cu²⁺ could promote the transformation of Fe²⁺ to Fe³⁺ and facilitating the oxidation regeneration of the system.

STUDY ON THE SYNTHESIS OF POLYCYCLIC AROMATIC HYDROCARBON RESIN FROM FCC DIESEL

2024, 55(11):  126-131. 

Asbtract ( 124 )   PDF  

References | Related Articles | Metrics

In this paper, FCC diesel was directly used as raw material to synthesize condensed polycyclic polynuclear aromatic hydrocarbon (COPNA) resin. Under the optimal cross-linking conditions of a FCC diesel:catalyst:crosslinker mass ratio of 1: 0.1: 0.35,a reaction temperature of 140 ℃,a reaction time of 14 h, and a curing temperature of 350 ℃, a curing time of 150 min, the yields of moderate condensation polycyclic aromatic hydrocarbon (B-COPNA) resin and thermosetting condensation polycyclic aromatic hydrocarbon (C-COPNA) resin were 73.22% and 56.14%, respectively. The results of gas chromatography-mass spectrometry (GC-MS) and Fourier infrared spectroscopy (FT-IR) showed that FCC diesel was rich in polycyclic aromatic hydrocarbons without long alkyl side chains and had small steric hindrance, which was suitable as a raw material for COPNA resin. The thermal behavior of the resin was studied by thermogravimetric analyzer, and it was found that the carbon residue rates of the synthesized B-COPNA resin and C-COPNA resin were 44.26% and 45.17%, respectively. After the reaction, the yield of diesel was 41.38%, the content of saturated hydrocarbon increased from 34.15% to 83.11%, and the cetane number of diesel increased from 33.13 to 42.39.

PREPARATION AND LUBRICATION PERFORMANCE OF PEG/PPG COPOLYETHER ESTER

2024, 55(11):  132-137. 

Asbtract ( 65 )   PDF  

References | Related Articles | Metrics

At present, polyether base oils are generally prepared by ring opening polymerization of epoxides. However, due to the flammable and volatile nature of epoxides, the requirements for safety production are more stringent. In order to solve the above problems, copolyether esters were prepared by polycondensation and decarboxylation of polyethylene glycol, polypropylene glycol and succinic acid with stannous chloride as catalyst. The structure and molecular weight were characterized by infrared spectroscopy (IR), nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC). The viscosity-temperature characteristics and lubrication performance of copolyether esters were investigated by using a kinematic viscosity tester, a four-ball friction tester and a 3D white light interferometer. The results showed that the viscosity of the prepared polyether ester was about 170 mm²/s at 40 ℃, the viscosity index was about 220. Under the conditions of 392 N, 30 min and 1 450 r/min, the wear spot diameter of the test steel ball was 0.55 mm, and the average friction coefficient was 0.057. The antifriction effect was significantly better than commercial base oil.

PREPARATION AND PROPERTIES OF SOLUBLE POLYIMIDES CONTAINING SIDE SUBSTITUENT AND FLUORENE

2024, 55(11):  138-143. 

Asbtract ( 91 )   PDF  

References | Related Articles | Metrics

A series of soluble polyimides (3a-3c) containing side substituent and fluorene structures were prepared by one-step high-temperature solution condensation polymerization using self-made diamine monomer 9,9-bis(3,5-dimethoxy-4-(4-amino-2-methylphenoxy) phenyl) fluorene and three commercial available aromatic dianhydride monomers: diphenyl ether tetracarboxylic dianhydride, biphenyl tetracarboxylic dianhydride and benzophenone tetracarboxylic dianhydride. The structure, solubility, thermal stability and mechanical properties of the polyimide were characterized by ¹H NMR, GPC, DSC and other equipment. The results showed that the polyimides could be well dissolved in N,N-dimethylacetamide, N-methylpyrrolidone, dimethylformamide, oxolane and other solvents. The glass transition temperature (T_g) of the polyimide was higher than 244 ℃, and the 10% mass loss temperatures in air and N₂ were higher than 460 ℃ and 500 ℃,respectively, which proved that the thermal resistance of the polyimide was excellent. The tensile strength of the film was above 78.7 MPa, and the elongation at break was above 7.9%, which indicated good mechanical properties. The permeability coefficients of the film to CO₂ and O₂ were higher than 15.9 and 4.95 barrer, respectively. The separation selectivity coefficients for CO₂/CH₄ and O₂/N₂ were as high as 46.42 and 4.93, which proved excellent gas separation performance. Therefore, this soluble polyimide with substituted side groups and fluorene structures exhibited excellent comprehensive performance.

SIMULATION AND OPTIMIZATION OF SEPARATION PROCESS FOR MIX C₅ FRACTIONS OF ALKANES

2024, 55(11):  144-148. 

Asbtract ( 75 )   PDF  

Related Articles | Metrics

The steady-state separation process of alkane C5 mixture was simulated by Aspen Plus V12 simulation software, in which the separated adjacent distillation column was used to replace the debutane removal column and C₅ pre-separation column in the original process, and on this basis, the sensitivity analysis tool was used to optimize the operating parameters of the adjacent distillation column. The results showed that the optimal feeding position of the raw material was the 11th tray, the reflux ratio was 5, the side line recovery position was the 7th tray, the side line recovery capacity was 500 kg/h, the gas phase reflux position was the 37th tray, and the liquid phase reflux position was the 12th tray. Compared with the conventional distillation process, on the premise of the same feeding conditions and product purity requirements, the cooling energy consumption is saved by 17.04% and the heating energy consumption is saved by 16.69% by adopting the adjacent distillation column process.

RESEARCH ON THE CONSTRUCTION OF GASOLINE OCTANE NUMBER MODEL BASED ON SSA-BP NEURAL NETWORK

2024, 55(11):  149-154. 

Asbtract ( 95 )   PDF  

References | Related Articles | Metrics

Based on the data of 100 groups of gasoline samples analyzed by near infrared spectroscopy, the prediction model of gasoline octane number (SSA-BP) was established by pre-processing with different methods and optimizing BP neural network model with the sparrow search algorithm (SSA). The predicted value of the model was fitted with the measured value of gasoline research octane number (RON) and compared with those results obtained by partial least squares model and BP neural network model. The results showed that the SSA-BP model had the highest prediction accuracy, with a validation set determination coefficient (R²) of 0.976 0 and a prediction standard deviation (RMSEP) of 0.326 after the standard normal variate transformation(SNV) data pre-processing. Among the three gasoline octane number prediction models, SSA-BP neural network model has the best prediction accuracy and good applicability and stability. It shows that the SSA-BP neural network model, which preprocesses the spectral data with SNV method, can be better used for the prediction of gasoline octane number. The prediction results have good accuracy, it can realize the rapid non-destructive detection of gasoline octane number.

ADVANCES IN HYDROPHOBIC CATALYSTS FOR FISCHER-TROPSCH SYNTHESIS

2024, 55(11):  155-161. 

Asbtract ( 189 )   PDF  

References | Related Articles | Metrics

Fischer-Tropsch synthesis (FTS) technology can convert coal and biomass-based syngas into high-value fuels and chemicals, which is important for achieving efficient use of carbon resources. However, water generated during the reaction process leads to side reactions such as water gas shift (WGS), which will affect the catalyst activity, stability and target product selectivity. By increasing the hydrophobicity of the catalyst, the removal rate of water can be significantly accelerated, the negative impact of water can be reduced, and the performance of FTS reaction can be improved. Focusing on the specific effects of by-product water on FTS reaction, the types of hydrophobic Fischer-Tropsch catalysts, preparation methods and principles of action were outlined, and the prospects for their development were prospected.

PROGRESS ON THE PREPARATION AND PROPERTIES OF BIO-ASPHALT

2024, 55(11):  162-170. 

Asbtract ( 115 )   PDF  

References | Related Articles | Metrics

Due to the limitation of petroleum asphalt supply and environmental protection considerations, the development of environmental-friendly renewable bio-asphalt has gradually become a hot spot. The kinds of biomass raw materials and the refining methods of biomass heavy oil(bio-oil) have a great impact on the performance of bio-asphalt. At the same time, the poor performance of bio-asphalt which is easy to age at high temperatures and embrittle at low temperatures limits its wide application. Therefore, it is of great significance to investigate the source, composition, structure and performance characteristics of bio-asphalt, and to select appropriate methods to modify bio-asphalt for the development of high-performance bio-asphalt. Based on this, the preparation process, composition and performance characteristics of bio-oil and bio-asphalt were comprehensively expounded and analyzed from the aspects of the refining process of bio-oil and the preparation characteristics of bio-asphalt. The modification method and mechanism of bio-asphalt were deeply summarized in order to provide a reference for the development of bio-asphalt modification technology and the wide application of bio-asphalt.