Table of Content

12 July 2024, Volume 55 Issue 7

Previous Issue    Next Issue

STUDY AND APPLICATION OF FLEXIBLE FLUID CATALYTIC CRACKING PROCESS TO MEET MARKET FLUCTUATION

2024, 55(7):  1-7. 

Asbtract ( 179 )   PDF  

References | Related Articles | Metrics

With the transformation of energy structure, the demand and price of refined oil and chemical products in market fluctuate sinusoidally. The existing refining transformation technology is irreversible and the production plan cannot be flexibly adjusted to meet market demand. Controlling single-molecule and bimolecular reaction path at micro scale was an effective method to solve the problem of inflexibility in the transition from refining to chemical industry in FCC process. It was proposed that the bimolecular reaction index could be used as a proportional measure of the occurrence of single-molecule and bimolecular reaction. The reaction temperature and the type of molecular sieve catalyst were two significant variables affecting the yields of liquefied gas and gasoline. The results showed that the yields of gasoline and (propylene + butene) over Y zeolite catalyst at 530 ℃ were 47.55% and 13.31%, respectively, and the yields of gasoline and (propylene + butene) over MFI zeolite catalyst at 580 ℃ were 22.05% and 31.45%, respectively. The relationship between reaction temperature and catalyst type ratio and the yield of target products was obtained, and the idea of flexible switching and adjustment of industrial plant production scheme was proposed to form a flexible and efficient catalytic cracking process. The industrial application results showed that the production scheme switching of (propylene + butene) and gasoline could be completed within a few weeks. Flexible production scheme provides technical ideas for low-cost progressive transformation and development.

STUDY ON CATALYTIC CRACKING PROCESS OF HYDROTREATED SHALE OIL

2024, 55(7):  8-14. 

Asbtract ( 78 )   PDF  

References | Related Articles | Metrics

To achieve efficient utilization of shale oil, nitrogenous compounds and other impurities in shale oil were removed by hydrotreating. The catalytic cracking of hydrotreated shale oil was investigated by using a small-scale fixed fluidized bed (FFB) unit. The effects of catalyst and reaction severity were studied by using SCG catalyst enriched with Y molecular sieves and DCC catalyst enriched with ZRP-type molecular sieves, respectively. The experimental results showed that catalytic cracking of hydrotreated shale oil, with nitrogen removal of 99.74%, achieved a high conversion rate ranging from 79% to 85%. The yield of liquid product was also high, ranging from 89% to 94%. The highest yield of gasoline was achieved by using the SCG catalyst, with the yield of 51.77% and research octane number(RON) of over 90 at a reaction temperature of 500 ℃ and a catalyst/oil mass ratio of 6. The data indicated that an increase in the conversion rate of hydrotreated shale oil resulted a linear decrease of gasoline yield. Furthemore, the utilization of the DCC catalyst led to higher yields of liquefied petroleum gas (LPG) and light olefins (ethylene + propylene + butene), reaching up to 41.62% and 32.90%, respectively,at a reaction temperature of 560 ℃ and a catalyst/oil mass ratio of 10.3. The LPG and light olefins yield increased significantly with the increase of conversion. The olefin content of gasoline decreased linearly with the increase of conversion on both catalysts, while the RON increased linearly. The two processing schemes for producing more gasoline and LPG from the cracking of hydrotreated shale oil were designed.

COMPARATIVE STUDY ON COMBINED PROCESSES OF FIXED BED RESIDUE HYDROTREATING WITH MIP OR DCC

2024, 55(7):  15-21. 

Asbtract ( 86 )   PDF  

References | Related Articles | Metrics

Under the conditions of liquid hour space velocity (LHSV) of 0.30 h^-1, hydrogen partial pressure of 3.0 MPa, hydrogen-oil volume ratio of 100 and temperature of 360 ℃, a mixed feedstock A with mass ratio of FCC slurry to heavy cycle oil (HCO) of 3:1 was used, and a fixed-bed hydrogenation experiment was carried out to obtain the hydrogenated heavy fraction with a yield of 99.78%. Four fixed bed hydrotreating experiments were carried out with Middle East residua (MM) and mixed feedstock B (heavy distillate of hydrotreated A: MM = 7.98:100 by mass ratio) at different depths with constant space velocity of MM, four kinds of hydrotreated residue were obtained, and then MIP and DCC experiments were carried out with four kinds of hydrotreated residue, respectively. The results showed that when residue hydrotreating was combined with MIP, the yield of light oil (gasoline+diesel) increased by 2.20 percentage points compared with that of non-combined process using the slightly hydrotreated residue based on 100% MM feed, and the yield of light oil (gasoline+diesel) increased by 2.52 percentage points compared with that of non-combined process using the deep-hydrotreated residue. When residue hydrotreating was combined with DCC, the yield of propylene was 1.22 percentage points lower than that of non-combined process.

FACTORS AND MECHANISM AFFECTING THE OIL REMOVAL EFFICIENCY FROM SLUDGE BY ULTRASONIC METHOD

2024, 55(7):  22-29. 

Asbtract ( 89 )   PDF  

References | Related Articles | Metrics

The ultrasonic oil removal technology is green and environmental friendly, butthe oil removal efficiency is not high, the mechanism is not clear, andhas not been widely applied in industryincurrently. A set of ultrasonic oil removal test equipment was designed for high oil bearing drilling cuttings and sludge in a certain oilfield in the South. Seven main influencing factors, such as ultrasonic frequency, ultrasonicpower, and ultrasonic temperature,etc., were investigated on the oil removal effect. The results showed that ultrasound frequency, ultrasound power, ultrasound action time, solid-liquid ratio (oil based drilling cuttings to water mass ratio), and pH, had a significant impact on the oil sludge removal effect, while ultrasound temperature and thetimeofultrasound treatment hadlittle effecton oil removal. Under the optimal process conditions, the oil removal rate reached 57.18%. When the shear force produced by ultrasonic cavitation is greater than the interaction force between oil and solid particles, the oiladsorbed on the surface of the solid particles is desorbed.Withthe increaseoftemperature and the decrease of solid-liquid ratio, the viscosity of the oil sludge decreased, and the ultrasonic cavitation enhanced. HSiO₃^- occupies the adsorption sites of oil sludge particles in weak alkaline environments, which can prevent the readsorption of oil and improve the oil removal efficiency.

PROBLEMS AND COUNTERMEASURES OF TREATING COCKING GAS OIL IN FURFURAL REFINING UNIT

2024, 55(7):  30-37. 

Asbtract ( 88 )   PDF  

References | Related Articles | Metrics

During processing of coker gatch in the furfural refining unit, coker gas oil contains more light components, which leads to the increase of carrying oil in various parts of the unit and the greater loss of materials and solvents. The distribution and properties of carrying oil and solvent loss were obtained by simulation calculation. Combined with actual operation, it was found that carrying oil was the key of solvent loss, and it was not suitable for refining. By calculating the influence of different reflux media and top temperature on solvent and material loss in the stripping column, it was suggested that the refined oil should be used as reflux to control the top temperature from 100 ℃ to 115 ℃, and the top of stripping column should not be refluxed. When the processing capacity was 44.2 t/h, the refined oil loss was less than or equal to 164.1 kg/h, the extracted oil loss was less than or equal to 185.1kg/h, and the loss of solvent carried away by the material could be reduced to 37.48 kg/h. The problem of hydrogen sulfide in dry distillation coker gas oil could be solved by upgrading the material of pipelines, adjusting the processes and operations. The load of refining oil heating furnace could be reduced by adjusting the heat exchange process, and the fuel gas and circulating water could be saved by 41 m³/h and 19 t/h,respectively. The coke powder in coker gas oil could be removed by adding backwash filter. Through appropriate modification and operational adjustment to deal with the problems of processing coker gas oil in the furfural refining unit, it could provide reference for the optimization of existing industrial units and the design of new units.

ANALYSIS AND OPTIMIZATION OF PRESSURE DIFFERENCE FLUCTUATION IN STRIPPING COLUMN OF AROMATICS EXTRACTION UNIT

2024, 55(7):  38-41. 

Asbtract ( 81 )   PDF  

References | Related Articles | Metrics

Aromatics extraction unit is one ofan important part in the aromatics complex, which uses sulfolane solvent to separate aromatics from non-aromatics. In daily production, it is found thatthe pressure difference of stripper oftenfluctuates abnormally, which seriously affects the process stability of extraction unit and the production continuity of aromatics complex. By studying the typical phenomenon of pressure difference fluctuation of stripper, the abnormal causes were analyzed from the aspects of temperature, pressure and feed composition, and the corresponding optimization measures and emergency disposal methods were put forward, such as increasing the operating pressure and feed temperature, reducing the content of light components in feed. After a series of optimizationand adjustment, the abnormal fluctuation phenomenon of the pressure difference of the stripper had not appeared again,the product quality had also been kept at a good level, and the process stability and production efficiency of the stripper have been improved. The reliable suggestions were put forwardfor the safety and economy of long term and high load operation of maintenance equipment.

COMMERCIAL APPLICATION OF LCO HYDROGENATION CONVERSION TECHNOLOGY

2024, 55(7):  42-47. 

Asbtract ( 66 )   PDF  

References | Related Articles | Metrics

The proportion of fluid catalytic cracking (FCC) units in petrochemical enterprises is very large. The high content of aromatic and nitrogen, high density and low cetane index of FCC light cycle oil (LCO) make hydrorefining difficult. Furthermore, the domestic demand of diesel is decreasing, it is necessary to find a suitable method to deal with LCO. SINOPEC Maoming Company used the FD2G LCO hydrogenation conversion technology developed by SINOPEC (Dalian) Research Institute of Petroleum Processing and Petrochemicals Co.Ltd. to retrofit its idle hydrogenation units to process LCO feedstock and produce high octane gasoline, by-product clean diesel and gas products. The unit run smoothly, the product was qualified, the diesel oil was reduced about 400 kt/a successfully. The aim of increasing gasoline production, solving the problem of diesel oil leaving the factory and increasing the benefit of the enterprise was achieved.

RESEARCH AND DEVELOPMENT OF HIGH SELECTIVITY CATALYST RIW-30 FOR LUBE HYDROISOMERIZATION DEWAXING

2024, 55(7):  48-53. 

Asbtract ( 93 )   PDF  

Related Articles | Metrics

Based on the mechanism of alkane hydroisomerization, by analyzing the properties of hydroisomerization dewaxing catalyst, a molecular sieve named as BCM-168 with special structure and suitable ratio of silica to alumina was synthesized. By controlling the key physical and chemical properties of BCM-168 and optimizing the components of catalyst, catalyst RIW-30 with high isomerization selectivity for lube oil isomerization dewaxing was developed. Theresults of industrial production and preparation repeatability testshowed that the molecular sieve and the catalyst preparation technology had good repeatability. When catalyst RIW-30 was used toprocess hydrocracking unconverted oil, hydrotreated vacuum gas oil and slack wax, the yield of main products was high and the loss of viscosity index was low. It has good activity, hydroisomerization selectivity and raw material adaptability. Compared with catalyst RIW-2, when catalyst RIW-30 was used to process hydrocracking tail oil,the viscosity index loss of the product decreased by 4 and the yield of main product increased by 4-5 percentage points.The results of industrial applications indicated that HVI III base oil could be produced by using catalyst RIW-30 under mild reaction conditions,with high yield of base oil and less loss of viscosity index, which meant that the overall performance of the catalyst RIW-30 was better than that of catalystRIW-2.

DEVELOPMENT AND THE FIRST COMMERCIAL APPLICATION TEST OF CATALYST SR-2000 FOR FIXED-BED NAPHTHA CATALYTIC REFORMING

2024, 55(7):  54-61. 

Asbtract ( 67 )   PDF  

Related Articles | Metrics

The alumina carriers were prepared by SB, ASIA and SRPA powders and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and N₂ adsorption-desorption. The results showed that the dense packing density of SRR carrier prepared from SRPA powder was increased by about 21%, the proportion of holes between 6-10 nm in the aperture volume distribution was significantly increased, and the proportion of holes above 10 nm was significantly reduced compared with that of SRH carrier prepared by ASIA powder. A new generation of naphtha reforming catalyst SR-2000 was developed with SRR as carrier. The catalyst SR-2000 was characterized by pyridine adsorption IR, in situ CO-IR and scanning transmission electron microscopy (Cs-STEM). The results displayed that the amount of medium-strong and weak L acid on catalyst SR-2000 was higher than that on catalyst SR-1000, and there were a large number of single or double Pt atoms on catalyst SR-2000 besides a small number of Pt clusters. Both the evaluation of the laboratory equipment and the first commercial application exhibited that catalyst SR-2000 had excellent catalytic performance for naphtha reforming in fixed-bed reactor.

SYNTHESIS OF ZSM-5 MOLECULAR SIEVE BY CRYSTAL SEED AND ORGANIC TEMPLATING AGENT RELAY-DIRECTED AND ITS CATALYTIC PERFORMANCE

2024, 55(7):  62-68. 

Asbtract ( 175 )   PDF  

References | Related Articles | Metrics

ZSM-5 zeolite was synthesized by the relay-oriented method of crystal seed and organic template agent, and the obtained ZSM-5 zeolite has similar crystalline structure, morphology, bulk Si/Al ratio, and pore structure to those of ZSM-5 zeolite synthesized by traditional methods. The performance of ZSM-5 zeolite synthesized by the relay method and traditional methods was compared on the reaction with 1,3,5-triisopropylbenzene catalytic cracking as probe. The results showed that the conversion of 1,3,5-triisopropylbenzene of ZSM-5 zeolite prepared by the relay method was low, which indicated that the surface of ZSM-5 zeolite prepared by the this method was rich in silicon and poor in aluminum. Furthermore, the zeolites synthesized by both methods were used as isomerization catalysts for ethylbenzene isomerization. Under the same reaction conditions, the ethylbenzene conversion of ZSM-5 zeolite prepared by the relay method was higher, but the isomerization activity and xylene loss rate were lower. It can be seen that crystal seed and organic template agent relaying is a feasible method to prepare core-shell molecular sieve with different aluminum content.

PREPARATION OF Co_0.6Ni_0.4/NC CATALYST AND ITS CATALYTIC PERFORMANCE FOR HYDROGEN PRODUCTION FROM AMMONIA BORANE HYDROLYSIS

2024, 55(7):  69-76. 

Asbtract ( 120 )   PDF  

Related Articles | Metrics

In order to improve the performance of ammonia borane (AB) hydrolysis for hydrogen production under mild conditions,a catalyst with both high activity and high stability was developed.Firstly, the zeolitic imidazolate frameworks material CoNi-ZIF (a type of metal-organic frameworks material) was prepared by directly stirring the reaction solution at normal temperature and pressure, and then the CoNi-ZIF precursor was calcined at high temperature to prepare Co_xNi_1-x/NC catalyst (where x represents the molar fraction of Co atoms, 0＜x＜1) supported on nitrogen-doped porous carbon (NC). The structure and morphology of  Co_xNi_1-x/NC catalyst were characterized by scanning spectroscopy microscopy,transmission electron microscopy, and X-ray photoelectron spectroscopy, and the catalytic performance of the catalyst for hydrogen production from hydrolysis of AB was investigated by changing the metal ratio of Co/Ni,the amount of catalyst, the concentration of AB, reaction temperature and other conditions. The results showed that Co_0.6Ni_0.4/NC with a Co/Ni molar ratio of 6∶4 had a larger specific surface area and the best catalytic activity, and the time of AB complete hydrolysis was the shortest at 298 K.The TOF value of Co_0.6Ni_0.4/NC catalyzing AB hydrolysis for hydrogen production was 1832.79 h^-1, and the activation energy of the reaction was 64.81kJ/mol. After 10 cycles of use, the rate of hydrogen production by catalyzing the complete hydrolysis of AB hadalmost no change, and the catalytic activity was still good.

COMMERCIAL TEST OF ETHYLBENZENE CONVERSION TYPE C₈ AROMATICS ISOMERIZATION CATALYST RIC-300

2024, 55(7):  77-80. 

Asbtract ( 53 )   PDF  

References | Related Articles | Metrics

The commercial test of ethylbenzene conversion type C₈ aromatics isomerization catalyst RIC-300 developed by SINOPEC Research Institute of Petroleum Processing Co., Ltd. was introduced. The performance of catalyst RIC-300 for the feedstock with high content of ethylbenzene was analyzed based on its first commercial application test in an aromatics plant. The results showed that the activity of catalyst RIC-300 was over 23.4% (p-xylene/xylene), the conversion rate of ethylbenzene was over 39.8%, and the loss rate of C₈ aromatics was 1.9% under mild conditions. Under the harsh operating conditions of high load and high conversion, the rate of raising temperature and pressure was low.The catalyst RIC-300 had the characteristics of high activity,high selectivity and good stability.

PREPARATION OF COBALT MOLYBDATE WITH LARGE SPECIFIC SURFACE AREA AND ITS AEROBIC OXIDATION DESULFURIZATION PERFORMANCE

2024, 55(7):  81-90. 

Asbtract ( 64 )   PDF  

References | Related Articles | Metrics

Cobalt molybdate catalyst with large specific surface area was prepared fromcobalt(II) chloride and ammonium molybdate with KIT-6 as hard template and alkali etching process. The morphology and structural of the catalyst were characterizedby X-ray diffractometer, scanning electron microscope,X-ray photoelectron spectroscopy, and N₂ adsorption desorption techniques. Using cobalt molybdate as catalyst and O₂ as oxidant, the catalytic oxidation of dibenzothiophene from simulated oil was studied. The effects of reaction temperature, O₂ flow rate, the amount of catalyst addition and sulfide type on desulfurization efficiency were investigated. The results showed that the optimal reaction conditions were as follows:a simulated oil amount of 20 mL,an amount of catalyst of 0.05 g,an O₂ flow rate of 200 mL/min, a reaction temperature of 110 ℃ and a reaction time of 60 min. Under this condition, the desulfurization rate could reach 96.2%,and the activity of the catalyst had not significantly decreased after 5 times of reuse. Mechanism studies showed that the formation of superoxide radicals in the presence of catalystwas the key to the high desulfurization activity of the catalyst.

SIMULATION STUDY ON REDOX REACTION TEMPERATURE OF PLATINUM OXIDE

2024, 55(7):  91-98. 

Asbtract ( 88 )   PDF  

References | Related Articles | Metrics

First-principles molecular dynamics was used to simulate the reduction reaction temperature of H₂ and platinum oxide, and the reaction mechanism was discussed. The results showed that the suitable temperature for platinum oxide reduction reaction was about 250 ℃ from the point of view of reducing energy consumption. There are two pathways for the reduction of PtO₂, one is the reduction from PtO₂ to PtO, and then to metal Pt; the other path is the direct reduction of PtO₂ to Pt. The reaction path is related to reaction pressure. The activation energy barrier of PtO reducing to Pt is higher than that of PtO₂ reducing to metal Pt.Because the difference of the reaction orbital energy level between PtO and H₂ is higher than that between PtO₂ and H₂,the electron transition between PtO and H₂ requires more energy than that between PtO₂ and H₂.

GENERATING DELTA-BASE DATA FOR CATALYTIC REFORMING BASED ON MOLECULAR-LEVEL MODEL

2024, 55(7):  99-105. 

Asbtract ( 61 )   PDF  

Related Articles | Metrics

Based on the maximum Shannon entropy states and partial physical properties of reforming feedstock, the change of molecular level of reforming feedstock during Delta-Base data generation was studied. The maximum Shannon entropy as the objective function was used, the relative molecular mass, the ratio of hydrogen to carbon, the composition and density of PIONA and the potential content of aromatics were taken as constraints, and the Delta-Base data of two different aromatics reforming feedstocks were calculated from the molecular level. The results showed that the mass fraction of aromatics in the product increased with the increase of the potential content of aromatics. The Delta-Base data can be generated by the molecular level mechanism model.

STUDY ON STRUCTURE CHANGE OF MEDIUM-TEMPERATURE COAL TAR HEAVY FRACTION IN EBULLATED BED HYDROTREATING PROCESS

2024, 55(7):  106-110. 

Asbtract ( 61 )   PDF  

References | Related Articles | Metrics

The hydrotreating experiment of medium-temperature coal tar was carried out on the pilot plant of ebullated bed, the hydrogen nuclear magnetic resonance spectroscopy (1H-NMR) of the medium-temperature coal tar feedstock pitch and hydrotreated tail oil were measured, and the structural changes of the medium-temperature coal tar heavy fraction during the ebullated bed hydrotreating process were investigated. The results showed that the total carbon number and the average side chain length of the average molecular structure of the hydrotreated tail oil decreased, the number of aromatic rings decreased and the number of naphthenic rings increased due to the saturation of aromatic rings to naphthenic rings. Because of the partial hydrogenation-ring-opening cracking of aromatic rings and ring-opening of naphthenic rings, the average total number of rings of the hydrotreated tail oil decreased. The higher the reaction temperature was, the more significant the structural change trend of the heavy fraction became. Within the range of experimental temperature, the aromatic ring condensation parameter (HAU/CA) of the hydrotreated tail oil increased firstly and then decreased with the increase of reaction temperature. It was suggested that the reaction temperature should be strictly controlled below (base+20 ℃) in order to avoid macromolecular condensation and reduce the generation of light hydrocarbons.

INVESTIGATION ON THE PERFORMANCE OF LONG-LIFE AND LOW-VOLATILE LUBRICATING GREASE

2024, 55(7):  111-118. 

Asbtract ( 77 )   PDF  

References | Related Articles | Metrics

Sodium amide lubricating grease and perfluoropolyether lubricating grease were prepared to meet the higher requirements of the performance of lubricating grease in the harsh working conditions of aerospace equipment, and the long-life low-volatile grease was prepared byadding antioxidant, antirust agent and extreme pressure antiwear agent, etc. The physical and chemical properties, lubrication properties, bearing life and rheology properties of commercial amide soap-based grease and the long-life low-volatility grease were studied. The results showed that compared with commercial amide soap-based grease, the long-life low-volatile ester had lesslossat high temperature and lower oil separation ratio, which indicated that it hadbetter colloidal stability.The wear spot diameter of the long-life low-volatile grease test steel ball was 0.46 mm, which was much lower than 1.03 mm of commercial amide grease.The bearing life was as long as 1228 h, which was much longer than 760 h of commercial amide grease.These results showed that it had better extreme pressure and antiwear performance, lubrication performance and oxidation stability, andhad a wider linear viscoelastic region and a stronger structure retention abilityat high temperature. Therefore,the long-life low-volatility grease has excellent comprehensive performance and can be used for lubrication of equipment under various special working conditions.

PREPARATION AND PERFORMANCE EVALUATION OF THIADIAZOLE DERIVATIVES

2024, 55(7):  119-124. 

Asbtract ( 48 )   PDF  

References | Related Articles | Metrics

In response to the high chemical oxygen demand (COD) of wastewater in the existing preparation process of thiadiazole derivatives,a new green process for preparation of thiadiazole derivatives was developed,using deionized water instead of ethanol as the reaction solvent, and introducing phase transfer catalyst to promote solid-liquid two-phase reactions.The structure of the product synthesized by the new process was characterized by infrared spectroscopy, liquid chromatography, mass spectrometry and other methods, andthe metal corrosion inhibition performance, extreme pressure performance and friction reducing performance of the synthesized product were evaluated by copper plate corrosion test and four ball test. The results showed that the COD of the wastewater produced by the new process was 2000 mg/L, which was significantly lower than that of the traditional process (700000 mg/L), indicating that the new process could meet the requirements of green environmental protection. 2,5-bis (tertnonyldithio)-1,3,4-thiadiazole was synthesized by traditional and new processes respectively, their metal corrosion inhibition performance, extreme pressure performance, and friction reduction performance are comparable, and superior to those of T561, a commercially available thiadiazole derivative metal deactivator.

PREPARATION AND PERFORMANCE EVALUATION OF ENVIRONMENTALLY FRIENDLY RUBBER OIL FOR INSOLUBLE SULFUR

2024, 55(7):  125-128. 

Asbtract ( 51 )   PDF  

Related Articles | Metrics

Oil-treated insoluble sulfur was prepared from environment-friendly rubber oil obtained from naphthenic vacuum side cut 1 distillate by hydrofining process, and its application performance was evaluated. The results showed that the oil-treated insoluble sulfur preparedby hydrofining processcould meet the requirements of EU 2005/69/EC regulation, andthe oil-treated insoluble sulfur prepared with this environmentally friendly rubber oil had excellent performance. This technology effectively expanded the application field of naphthenic vacuum side cut 1 distillate and realized the transformation of oil productto special chemicals.

THE DETERMINATION OF TRACE IMPURITIES IN ISOPRENE BY CENTRAL CUTTING GAS CHROMATOGRAPHY

2024, 55(7):  129-134. 

Asbtract ( 58 )   PDF  

References | Related Articles | Metrics

The polymeric grade isoprene produced by the extraction and distillation method with dimethylformamide (DMF) contains trace impurities such as cyclopentadiene, 2-butyne, iso-pentenylene, 1-pentyne, cis-1,3-pentadiene, trans-1,3-pentadiene, DMF, and p-tert-butylcatechol (TBC). A gas chromatography method was developed for the determination of these eight trace impurities by central cutting technique with HP-1 as the main analytical column and CP-Al₂O₃/Na₂SO₄ as the auxiliary analytical column. The results showed that 8 kinds of trace impurities could be separated and analyzed on a set of chromatograms by this method; the recovery rates were 95.6%-104.9%, the relative standard deviation was less than 2.2%, indicating high accuracy and reliability. Compared with the general method, the sensitivity of isoprene analysis was significantly improved by changing the packed column chromatography system to the capillary column system, it could meet the analysis requirements of isoprene and butyl rubber raw materials, and the accuracy of analysis results could be improved by using external standard method. It could simultaneously measure the content of DMF and TBC, saving analytical instrument resources and reducing workload. This method has been used for daily quality monitoring of isoprene, and its stability and reliability have been fully verified.

SIMULATION ON OPERATION OPTIMIZATION OF CYCLONE SEPARATOR IN REGENERATOR OF MTO UNIT

2024, 55(7):  135-143. 

Asbtract ( 88 )   PDF  

References | Related Articles | Metrics

Cyclone separator is a common gas-solid two-phase separation equipment in methanol to olefins (MTO) unit, and its separation efficiency is very important for the long-term stable operation of the unit. Due to the use of a highly active catalyst in a 0.6 Mt/a MTO unit, the main air volume of the regenerator was lower than the design value, which resulted in low gas velocity at the inlet of the first-stage cyclone separator and increased loss of the fine powder catalyst under 20 μm in the unit, and catalyst consumption increased. For this purpose, the commercial computational particle fluid dynamics (CPFD) software was used to simulate the different operating conditions of the four group two-stage cyclones in the regenerator. The inlet gas velocity of the cyclone was changed by adjusting the inlet flow area and main air volume of the cyclone, and the effect of gas speed on the cyclone pressure drop and separation efficiency of the cyclone was studied. The results showed that when the main air volume was 42 241 m³/h, the gas velocity of cyclone separator could be increased by 3 m/s and the total efficiency of cyclone separator could be increased by 0.501 percentage points. Based on the simulation results, the optimal operation suggestions for cyclone separator were put forward, which could be applied to the operation adjustment of other MTO devices.

PROCESS SIMULATION OF LIGHT GASOLINE ETHERIFICATION UNIT

2024, 55(7):  144-151. 

Asbtract ( 62 )   PDF  

References | Related Articles | Metrics

The main process flow of 0.4Mt/alight gasoline etherificationunitwas systematically simulated and calculated by usingsteady-state process simulationsoftware PRO/II, andthe thermodynamic method selection of software modeling, the module selection of important equipment, the process modeling process and its main settings were introduced. The resultsof model validationindicatedthat the constructed model had high accuracy and applicability.In order to achieve the maximum conversion rate of active olefins andensure the quality of C₅ components, the methanol injection amountand reflux ratio in the etherification fractionation column were determined by the established model, and the parameters ofextractionwater,water content in the circulating methanol and the methanol contentin the extraction waterof methanol recovery unit were optimized. The methanol injection amount of the etherification fractionation column was controlled at 8.8% of the feed methanol amount, the reflux ratio of the etherification fractionation columnshouldbe controlled at 2.0,the extraction water amountwas controlled at 10-11t/h,and the mass fraction of methanolin the extraction water andwater in the circulating methanol was controlled 0.04% and 0.016%, respectively.

PROGRESS IN N-FORMYLATION OF CARBON DIOXIDE

2024, 55(7):  152-162. 

Asbtract ( 93 )   PDF  

References | Related Articles | Metrics

N-formylation of carbon dioxide (CO₂) is the reaction of CO₂ with organic amine in the presence of a reducing agent to form N-formamide compound. The N-formylation reaction of CO₂ can be used as a resources to reduce greenhouse gas emissions, andcan convert cheap CO₂ into highvalue-added organic chemicals such as N,N-dimethylformamide and N-formylmorpholine,etc., expandsthe CO₂ downstream conversion and utilization of the reaction network. Inthis paper,the catalyst system, catalytic mechanism, and reaction process of N-formylation of CO₂ in recent yearswere reviewed, and the problems in the research and future developmentof the reactionwere also discussed.

CHARACTERISTICS AND APPLICATION PROSPECTS OF VANADIUM-BASED HYDROGEN STORAGE ALLOYS

2024, 55(7):  163-169. 

Asbtract ( 109 )   PDF  

References | Related Articles | Metrics

Vanadium-based alloy is a good hydrogen storage material because of its high hydrogen storage capacity, mild hydrogenstorage and desorptionreaction conditions, excellent reaction kinetics properties of hydrogen storageand good anti-pulverization properties. However,vanadium-based hydrogen storagealloys have some disadvantages, such aslow hydrogen storage platform, low reversible hydrogen storage capacity, obvious hysteresis, poor cycle stability, high cost of raw materials and high metal cost, it restricts the further application of vanadium-based hydrogen storage alloys. So far, researchers have modified the vanadium-based hydrogen storage materials by many ways, such as elemental composition and crystalline phase structure, to optimize the performance of vanadium-based hydrogen storage materials. Based on this, the research progress of doping Ti, Cr, Mn, Zr and other chemical elementand the optimization of particular conditions for hydrogen storage alloys were briefly reviewed in order to reduce the platform pressure ofhydrogenation and increase the reversible hydrogen storage capacity of materials. The effects of element replacement, material heat treatment, and alloy activation pretreatmenton hydrogen storage properties of vanadium-based hydrogen storage alloys were emphasized. The future development prospect of vanadium-based hydrogen storage alloyswas prospected.

RESEARCH PROGRESS OF STEAM POWER SYSTEM OPTIMIZATION IN PETROCHEMICAL ENTERPRISES

2024, 55(7):  170-176. 

Asbtract ( 122 )   PDF  

Related Articles | Metrics

Steam power system is an important part of petrochemical enterprises, but also the main link of energy consumption, with great energy-saving potential. Optimization of steam power system structure and operating parameters can significantly reduce operating costs, which is of great significance in saving energy, reducing carbon and creating efficiency in petrochemical enterprises. The basic methods, research progress and application of steam power system optimization were reviewed, and the optimization methods of steam power system, such as heuristic method, meta-heuristic method, thermodynamic objective method and mathematical programming method, were emphatically introduced. On this basis, the uncertainty optimization and multi-objective optimization of steam power system were reviewed. The uncertainty factors of steam power system were summarized, and the research progress of steam power system optimization under uncertainty was introduced. The optimization objectives of steam power system were summarized, and the multi-objective optimization modeling and solution methods of steam power system were introduced. Finally, the development direction of steam power system optimization was proposed.