Table of Content

12 March 2021, Volume 52 Issue 3

Previous Issue    Next Issue

EFFECTS OF OLEFIN STRUCTURES AND HYDROGENATION PERFORMANCE ON OCTANE NUMBER OF HEAVY FCC GASOLINE FRACTION

2021, 52(3):  1-7. 

Asbtract ( 448 )   PDF  

References | Related Articles | Metrics

The effects of olefin structure, carbon number and content in heavy FCC naphtha(HCN) gasoline on octane number of HCN were studied, and the effects of hydrogenation performance of olefins by HDS process on octane number of HCN were analyzed by means of calculation and experiment. The results showed that when the conversion amount of olefins with different carbon numbers was the same, the influence degree of carbon numbers on octane number of HCN was in the order of C₈ > C₇ ≈ C₉ > C₁₀. When the olefin content is considered comprehensively, the same conclusion was drawn. The results of experiment also showed that under the same process conditions, with the increase of olefin carbon number, the hydrogenation saturation rate of olefin decreased and the hydrogenation difficulty increased. It is showed that the octane loss of HCN was mainly caused by hydrogenation saturation of C8 olefins

PRESSURE DROP CHARACTERISTICS OF DISTRIBUTOR IN GAS-LIQUID CONCURRENT UP-FLOW REACTOR

2021, 52(3):  8-16. 

Asbtract ( 460 )   PDF  

References | Related Articles | Metrics

The pressure drop characteristic of new and reference gas-liquid distributors and the effect of flow rates of gas and liquid on the pressure drop were studied in a cold gas-liquid concurrent up-flow reactor model device. The results showed that for both two type of distributors, the pressure drop increased first and then decreased with the increasing gas flow rate, while increased with liquid flow rate up. However, the pressure drop of new gas-liquid distributor was larger than that of the reference one under the same conditions. The relevant mathematical model was established to predict the pressure drops for two gas-liquid distributors, including bottom part inlet pressure drop, middle part rising tube pressure drop, and top outlet pressure drop. The model calculation and verification results showed that in reference gas-liquid distributor, the top part pressure drop dominated, while in the bottom part and middle part was less, where the gravity pressure drop accounted for the largest proportion in the middle pressure drop, and the acceleration pressure drop could be ignored. The trend of pressure drop calculated by the model was basically the same as that of the experimental value with the liquid flow rate, but the calculated value of pressure drop was larger than the experimental value under the same conditions, and the deviation between them gradually increased with the increase of liquid flow rate. The reason was that the flow pattern of gas-liquid two phases in the actual distributor will change, which leads to the deviation of the calculated value of the model becoming larger.

COMBINED PROCESS OF EBULLATED BED HYDROCRACKING AND DELAYED COKING TO PREPARE LOW SULFUR COKE

2021, 52(3):  15-20. 

Asbtract ( 348 )   PDF  

References | Related Articles | Metrics

The fluidized bed residue hydrotreating technology has a remarkable effect on the desulfurization and quality improvement of coking feedstock. The high quality coke prepared by combined process of ebullated bed hydrocracking and delayed coking was investigated and the coking law of unconverted oil（UCO） from ebullated bed was explored. The results showed that the temperature increase or the space velocity decrease were beneficial to residue conversion and impurity removal in the ebullated bed hydrogenation process. Within the same operating range，residue conversion rate was significantly higher than the impurity removal rate. With the increase of residue conversion，sulfur content of UCO decreased first and then increased. In the process of UCO coking，about 60% of sulfur from UCO was transferred into coke，higher than the sulfur ratio into the coke from residue coking process（about 42%），and the quality of petroleum coke prepared by UCO can be significantly improved compared with residue as feed. The yield and sulfur content of petcoke from UCO feed has a good linear relationship with carbon residue and sulfur content of UCO，which can be used to guide the optimization of ebullated bed hydrocracking process according to the required low sulfur coke grade.

STUDY ON REAL-TIME MEASURING METHOD FOR CATALYST/OIL RATIO IN FCCU RISER

2021, 52(3):  21-23. 

Asbtract ( 211 )   PDF  

References | Related Articles | Metrics

The catalyst/oil ratio in the riser of FCCU has an important influence on the reaction depth. It is necessary to monitor and regulate the catalyst/oil ratio in real-time. A real-time measuring method for catalyst/oil ratio in the riser of FCCU was proposed based on the relationship between pressure drop and particle mass flow rate in the T-bend at exit of the riser. The results indicated that the method is feasible and the measured data is credible.

HYDROGEN DONATING ABILITY OF PETROLEUM DISTILLATES AND RESIDUES IN VISBREAKING UNDER HYDROGEN

2021, 52(3):  24-28. 

Asbtract ( 255 )   PDF  

References | Related Articles | Metrics

In order to study the hydrogen donating ability of heavy oils in upgrading process under hydrogen, Venezuela crude oil was cut into three distillates and residue. The hydrogen donating abilities of hydrogen, oil samples, and oil samples under hydrogen atmosphere were determined by using anthracene as a probe. Superposition method was used to analyze the synergic effects between oil sample and hydrogen. The effects of oil composition and structure on activation of hydrogen were studied indirectly. The results showed that the content of alkanes, naphthenes as well as tetrahydro-naphthalene had a positive impact on hydrogen donating ability of oils; the hydrogen donating ability of the whole reaction system under hydrogen was about 100% higher than the sum of hydrogen donating ability of hydrogen and oil respectively, indicating the positive synergism between hydrogen and oil. In addition, the difference of oil composition, such as polycyclic aromatics, sulfur and metals, could promote the activation of hydrogen molecule.

PREPARATION OF MILLIMETRE-SIZE Al2O3-ZSM-5 PELLETS AND AROMATIZATION PERFORMANCE OF Ga SUPPORTING CATALYST

2021, 52(3):  29-33. 

Asbtract ( 385 )   PDF  

References | Related Articles | Metrics

Considering the low crushing strength and high attrition loss of the zeolite pellets prepared by the existing process, the feasibility of preparing sol by peptizing pseudo-boehmite powder, ZSM-5 molecular sieve and acid solution, and then preparing millimeter-size Al₂O₃-ZSM-5 pellets by hot oil-drop method, was studied. By optimizing the ratios of raw materials, peptizer and gelling agent, the droplets can shrink into pellets in the hot oil column and have sufficient strength to facilitate subsequent washing, drying and roasting. The crushing strength of Al₂O₃-ZSM-5 pellets prepared reached 39 N/pellet, the bulk density was 0.59－0.70 g/cm³, and the attrition loss was lower than 2%, meeting the demand of moving bed reaction. The Ga-supporting catalysts were prepared by using the prepared pellets as carrier. Compared with the unsupported catalyst, the isobutane aromatization result of the catalyst with optimum Ga loading showed that the dry gas yield decreased by 2.48 percentage points, and the aromatics yield increased by 26.72 percentage points.

INDUSTRIAL APPLICATION OF HYDROGENATION TECHNOLOGY FOR OLEFIN REMOVAL FROM REFORMATE

2021, 52(3):  34-37. 

Asbtract ( 431 )   PDF  

Related Articles | Metrics

The industrial application of hydrogenation technology for olefin removal for reformate from continuous catalytic reformer in Shandong Chambroad Petrochemical Co. Ltd. was introduced. Using the HER process and TORH-1 catalyst, and the reformate oil with bromine index more than 5 000 mgBr/(100 g) as feed, the bromine index of hrdrotreated oil and the depentanizer bottom oil were both less than 100 mgBr/(100 g), with the conversion rate of olefin more than 98%. The bromine index of depentanizer overhead oil and aromatic raffinate could meet the production requirements, and the indexes of benzene, toluene and xylene were stable and qualified. The industrial application results show that hydrogenation technology for olefin removal could replace the existing clay process or greatly extend the service life of clay with obvious economic and environmental benefits.

DEVELOPMENT AND APPLICATION OF FCC GASOLINE HYDROUPGRADING TECHNOLOGY GARDES-II

2021, 52(3):  38-45. 

Asbtract ( 280 )   PDF  

Related Articles | Metrics

Using macroporous alumina carrier and new Mo(W) hybrid nanocrystalline active metal precursor, three main catalysts, GDS-22, GDS-32 and GDS-42, applied in GARDES-II FCC gasoline hydroupgrading technology was developed by using alumina crystal plane control technology, molecular sieve in-situ composite method and innovative catalyst preparation method and applied on the 1.2 Mt/a FCC gasoline hydrogenation unit of PetroChina Ningxia Petrochemical Branch Company in August 2017. The results showed that compared with the first generation GARDES technology, GARDES-II technology with the new catalysts showed stronger comprehensive ability of ultra-deep desulfurization, olefin reduction and octane number maintenance. In addition, GARDES-II technology has been applied in gasoline hydrogenation units of 5 companies including PetroChina Hohhot Petrochemical Company. The total processing capacity of the units has reached 6.5 Mt/a. Among them, the sulfur mass fraction of blended gasoline of Hohhot Petrochemical Company was reduced to 6.5-8.0 μg/g. The doctoral test was passed, the olefin volume fraction was reduced by 7.0 to 11.0 percentage points, and the gasoline octane number loss was 1.1 to 1.3. The output gasoline could meet the China VI (A) clean gasoline standard through the whole plant blending.

PREPARATION OF ECOFRIENDLY RUBBER PLASTICIZER BYHYDRIFINING-FURFURAL EXTRACTION FROM NAPHTHENIC-BASE HVGO

2021, 52(3):  46-49. 

Asbtract ( 240 )   PDF  

References | Related Articles | Metrics

The environmental friendly rubber plasticizer with high CA value was prepared in laboratory by two kinds of combined processes: hydrofining-single stage furfural extraction and hydrofining-two stage furfural extractions, using naphthenic-base HVGO of SZ36-1 crude as raw material. The results showed that both of the combined processes could produce the rubber plasticizers meeting the specifications of national standard. Rubber plasticizer A1220 could be produced by hydrofining-single stage furfural extraction with higher yield; while rubber plasticizer A1820 with higher CA could be produced by hydrofining-two stage furfural extractions.

EFFECT ANALYSIS OF FCC NAPHTHA USED AS QUENCH OIL IN RISER

2021, 52(3):  50-55. 

Asbtract ( 325 )   PDF  

References | Related Articles | Metrics

In order to reduce the olefin content of stable gasoline, FCC naphtha was used as quench oil in riser in a 4.8 Mt/a FCC unit of CNOOC Huizhou Petrochemical Company. It was found that the recycle of FCC naphtha into riser as quench oil had influence on product property and distribution, pressure distribution of oil and gas pipeline as well as energy consumption. The results showed that the volume fraction of olefins in the stable gasoline decreased by 1.3 percentage points when the quench oil naphtha was 15 t/h. Compared with that before the recycle of FCC naphtha, FCC conversion rate increased from 76.07% to 76.12%, the yield of coke increased from 7.29% to 7.74%, and total liquid recovery decreased slightly; the ratio of benzene to aromatics in gasoline decreased from 4.07% to 3.93%, sulfur transfer coefficient decreased from 2.89% to 2.28%; density of light diesel (20 ℃) increased from 948 kg/m³ to 951 kg/m³; the energy consumption increased by more than 90 MJ/t; the pressure drop from the outside of VQS to the inlet of air compressor increased by 2.5 kPa. The problem of salt deposition in the top tray and top circulation system of the fractionator was alleviated by the recycle of FCC naphtha.

Par-Isom C₅ /C₆ ISOMERIZATION TECHNOLOGY AND ITS INDUSTRIAL APPLICATION

2021, 52(3):  56-61. 

Asbtract ( 361 )   PDF  

References | Related Articles | Metrics

In order to upgrade the quality of gasoline pool to meet the China Ⅵ emission standard for motor gasoline, PetroChina Qingyang Petrochemical Company selected UOP，s Par-Isom C₅/C₆ isomerization process and " deisopentane column and isomerization reaction" process to produce high octane number C₅/C₆ isoalkanes from light naphtha and raffinate. The product had low density without olefins, aromatics and sulfur. The results of industrial application showed that the product yield of isomerized gasoline was 98.42%, the research octane number reached 83.3, 7.3 units higher than feed, sulfur mass fraction was 0.34 μg/g, RVP was 110-120 kPa, all quality indexes of the product were qualified, reached design index of the unit. The octane number of gasoline pool was increased, and the distribution of octane number of gasoline pool was optimized.

GENERATION, INFLUENCE AND CONTROL MEASURES OF UNVAPORIZED FEEDSTOCK IN FCC UNIT

2021, 52(3):  62-68. 

Asbtract ( 255 )   PDF  

References | Related Articles | Metrics

Based on the composition of coke in FCC reaction system，the existence of unvaporized oil was determined. The generation and concentration process of unvaporized oil was discussed, and the generation conditions and the hazards of unvaporized oil were analyzed. Six FCCUs were selected to judge the degree of feedstock vaporization by comparing the temperature of reaction vaporization sector and the dew point of feedstock，and the causes of the generation of unvaporized oil were analyzed from the microscopic point of view. Finally，the control measures were proposed to guide the production. It was found that it was difficult to avoid the occurrence of unvaporized oil in RFCC unit，though it had little impact on the operation of most units. It would cause coking of reaction system and scaling of flue gas expander under specific conditions. Therefore，the generation of unvaporized oil should be reduced as much as possible.

INFLUENCE OF TRACE WATER ON ANTI-WEAR AND ANTI-FRICTION PROPERTIES OF OIL CONTAINING DETERGENT

2021, 52(3):  69-76. 

Asbtract ( 180 )   PDF  

References | Related Articles | Metrics

The effect of five detergents on friction reduction and wear resistance of lubricating oil under water pollution was studied by using high frequency reciprocating rig. The results showed that all detergents tested enhanced the anti-wear and anti-friction properties of the base oil. The detergent C with high base value had the best lubricating effect on base oil, and the friction coefficient was only 0.10. Water had little influence on the anti-wear performance of oil samples with detergent A, B and E, but had greater influence on the anti-wear performance of oil samples with detergent C and D. When the addition of detergent C (w) was 2.0% and the addition of water (w) was 0.1% and 0.3%, the average wear scar diameter of the steel ball increased to 410.0 μm and 416.0 μm, respectively, and the wear resistance of the oil product became significantly worse. For detergents containing the same organic acid matrix type, the stronger the water solubility of overbased components is, the larger the wear scar diameter of steel balls when corresponding oil products are tested; oil products containing the same metal type and different organic acid matrix detergents have different trends in friction coefficient and wear scar morphology.

INFLUENCE OF CHARACTERISTIC FUNGI ON PROPERTIES OF JET FUEL

2021, 52(3):  77-82. 

Asbtract ( 238 )   PDF  

References | Related Articles | Metrics

In order to investigate the effect of characteristic fungi on jet fuel properties, a mixed characteristic fungi culture system with jet fuel as the sole carbon source was constructed, and the effects of characteristic fungi on jet fuel appearance, total acid value, silver sheet corrosion, water reaction test and surface tension were systematically studied. Combined with ATP bioluminescence detection method, the relationship between total microbial contamination and jet fuel quality index was investigated. The results showed that in the process of growth and reproduction, the characteristic fungi would cause the appearance of jet fuel not to meet the standard requirements, and produced acidic substances and surface active substances, which increase the acid value and decrease the surface tension of jet fuel. It has no significant effect on the water reaction test of jet fuel and the corrosion of silver sheet during the test period. When the ATP content in jet fuel was greater than 5500 RLU/L, the jet fuel would be heavily polluted by microorganisms, causing the total acid value to exceed the standard.

PREDICTION OF FIBER FOULING TENDENCY IN SWEETENING PLANT BASED ON PROCESS SIMULATION

2021, 52(3):  83-86. 

Asbtract ( 253 )   PDF  

References | Related Articles | Metrics

The technology of fiber membrane was adopted in the LPG sweetening system of SINOPEC Qingdao Refining and Chemical Co. Ltd. The small molecule mercaptan and H₂S in LPG reacted with alkali solution to generate sodium mercaptan compound and sodium sulfide，which was dissolved in alkali solution to realize the removal of mercaptan and H₂S. In the operation，the fiber surface had obvious scaling tendency. When the fiber is scaling and entangled，the alkali liquor couldn't be uniformly dispersed，and the liquefied gas "short circuit" would occur. If the contact between alkali liquor and LPG was not enough，the mercaptan content in refined LPG would exceed the standard. Through the solution potentiometric titration and X-ray spectrum analysis of the scale sample on the fiber surface，it was found that the main component was Na₂CO₃. Aspen Plus was used to simulate and calculate the operation conditions of the sweetening system to find out the optimization operation conditions to ensure the long-term operation of the fiber membrane contactor.

BP NEURAL NETWORK SYSTEM FOR YIELD ANALYSIS OF FCC UNIT BASED ON OPEN SOURCE TECHNOLOGIES

2021, 52(3):  87-92. 

Asbtract ( 326 )   PDF  

References | Related Articles | Metrics

The product yield estimation is a crucial part of the whole plant design in the early stage of petrochemical engineering. Previous research has shown the neural network technologies can perform higher efficient yield prediction than traditional manual estimation and is one of the major trends of the petrochemical engineering informatization in the early stage. In this paper, we designed and preliminarily implemented a petrochemical neural network system using Python and PHP as the implementation means, and established a combination model for the yield prediction of fluid catalytic cracking (FCC) unit (MIP process) applicable to the early stage of petrochemical design.The results show that the yields of MIP process predicted by the neural network models are consistent with actual yields in production process.

PROCESS SIMULATION AND ANALYSIS OF TWO-PHASE FLOW IN VACUUM TRANSFER LINES

2021, 52(3):  93-98. 

Asbtract ( 319 )   PDF  

References | Related Articles | Metrics

The modeling of two-phase flow was analyzed by using process simulation software PROII with the aim of predicting the distributions of pressure，temperature，evaporation rate as well as volumetric ratio of vapor to gas （G/L） in a vacuum transfer line. The model was developed based on the pressure drop model and the multi-stage flash model. The results indicated that the pressure drop，temperature decline， the variation of evaporation rate and G/L primarily occurred in the transition section and the junction site of the transfer line. In comparison with the high-velocity transfer line，the pressure and temperature decline was clearly higher in the case of the low-velocity transfer line. In the premise of the evaporation rate at the outlet of transfer line remaining approximately the same，the temperature at the inlet of transfer line was lower in the case of the low-velocity transfer line，which means more efficient energy transfer. Meanwhile，the low-velocity transfer line offered more moderate change of evaporation rate and G/L ratio，in favor of decreasing the amount of liquid entrainment at the feed section of a vacuum tower. Furthermore，the predictions were in good agreement with the industrial field data in the case of the low-velocity transfer line，which verified the reliability of the model.

DESIGN OPTIMIZATION FOR LARGE AROMATICS COMPLEX IN REFINING-CHEMICAL INTEGRATION

2021, 52(3):  99-104. 

Asbtract ( 268 )   PDF  

Related Articles | Metrics

Based on the analysis of C₈ aromatics source, the design of C₈ aromatics isomerization unit in the aromatics complex was optimized. According to the process characteristics of aromatic complex unit, the steam balance of the whole plant was optimized by using ultra-high pressure steam and comprehensive utilization of low temperature waste heat, and the cascade utilization of steam in the whole plant was realized, which reduced the operation cost of the integrated refining and chemical processing. Based on the comprehensive analysis of C₈ aromatics resources in aromatics complex, the energy saving schemes and the evaluation of new technologies, the optimization ideas were put forward to provide the basis for further improving the economy of the unit, reducing operating cost and enhancing the competitiveness of enterprises. The application of new technologies in aromatics complex is feasible to further reduce the energy consumption of aromatics complex.

STUDY AND ECONOMIC ANALYSIS ON HYDROGENATION OF C4 FOR ETHYLENE PRODUCTION

2021, 52(3):  105-109. 

Asbtract ( 317 )   PDF  

Related Articles | Metrics

Using C₄ fraction as raw material, hydrogenation experiment was carried out in a small fixed bed unit with self-made catalyst. The results showed that the olefin mass fraction in hydrogenated C₄ fraction decreased to 2.32%, the total yield of ethylene, propylene and butadiene reached 48.16%-50.94% after simulated evaluation of hydrogenated C₄ pyrolysis. A simple economic analysis of hydrogenated C₄ was carried out. The results indicated that in terms of the yield of three kinds of olefins, one ton hydrogenated C₄ was equivalent to 0.917t ethylene feedstock, indicating that the hydrogenated C₄ is a better feedstock for ethylene production.

FACTORS INFLUENCING FORMATION OF FOAM LAYER IN COKE TOWER AND INHIBITION METHOD

2021, 52(3):  110-116. 

Asbtract ( 365 )   PDF  

References | Related Articles | Metrics

Based on the theoretical mechanism of foam layer formation and decay in coke tower, the effects of feed（residual oil）composition, coking products and operation conditions on foam layer were analyzed, the methods of inhibiting foam layer were put forward, and the research prospect of foam layer in delayed coking tower was prospected. It is showed that the properties of foam layer could be determined by the feed composition, and coking products ，and operation conditions also had a vital influence on foam layer.