Table of Content

12 May 2018, Volume 49 Issue 5

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IMPROVEMENT OF PARA-XYLENE ADSORPTION SEPARATION PROCESS

2018, 49(5):  1-5. 

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The model of simulated moving bed (SMB) for para-xylene separation by adsorption was established. The influence of the bed number ratio in each functional zone, the void volume between beds, and the total bed number on adsorption performance was investigated. Results showed that the optimized ratio of the bed number in adsorption zone over that in the purification zone is in the range of 0.5-0.7; the optimized ratio of the bed number in desorption zone / the purification zone is in the range of 0.4-0.5. The suitable ratio for buffer zone over total bed number is 8.5%-13.0%. Increasing the total bed number and decreasing the void volume can improve the separation efficiency of the process. Test results indicated that the optimized bed numbers in each zone (desorption, puri?cation, adsorption, and buffer zone) is 3, 7, 4, 2. This configuration reduces the number of adsorbent bed and adsorption tower under the premise of basically the same process performance.

UPGRADING OF IDLE DIESEL HYDROGENATION UNIT FOR C5/C6 ISOMERIZATION AND INDUSTRIAL COMMERCIALIZATION

2018, 49(5):  6-11. 

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Appling the zeolitic C5/C6 isomerization technology developed by SINOPEC Research Institute of Petroleum Processing (RIPP)， an idle 0.25 Mt/a diesel hydrotreating unit at ShanDong Dongming Petrochemical Grouphas been revamped to a C5/C6 isomerization unit. The feed is C5/C6 light naphtha and raffinate. from CCR unit。Based on principles of feeds’properties， maximum utilization on idle facilities and minimizing investment，the revamp proposed a deheptanizer for raffinate and a “DIP + Once-through” process for the isomerization， producing the C5/C6 isomerate gasoline with RON of 79.7.Unit performance test run indicates that the C5 and C6 isomerization rate of the zeolitic catalyst is 63.2% and 81.1%， respectively. The isomerate achieves an RON of 79.7 and a yield of 98.0%. All the operational results meet the technical control indices.The unit has provided a referential technical solution for the revamp of similar hydrotreating units.

DEVELOPMENT AND COMMERCIAL APPLICATION OF NHTDC TECHNOLOGY TO PRODUCE AROMATIC EXTRACTION FEED FROM DCC GASOLINE

2018, 49(5):  12-15. 

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The properties and hydrocarbon composition of DCC gasoline were investigated. Based on the results, the NHTDC technology was established for producing aromatic extraction feed from DCC gasoline. Long term industrial operation showed that the aromatics extraction feed with sulfur and nitrogen content of less than 1μg/g, bromine value less than 0.5 gBr2/ (100 g) can be obtained by NHTDC technology using DCC gasoline with sulfur content of 50 - 350μg/g, nitrogen content of 19 - 69μg/g and bromine value of 20 - 71 gBr2/ (100 g). The product quality can maintain stable and the unit can run steadily, even if the sulfur content, nitrogen content and Bromine number of material varies in a large range.

EXPERIMENTAL STUDY OF HEAVY OIL PRETREATMENT BY ENHANCED MASS TRANSFER MEMBRANE TECHNOLOGY

2018, 49(5):  16-21. 

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Pretreatment of heavy crude oil is generally difficult. The operation of two sets of desalting devices in Tahe Co., is poor, and the average content of salt basically remains at 10-12 mgNaCl/L. It brings great difficulties to the corrosion prevention and safe operation of the subsequent distillation and hydrogenation units. Tahe heavy crude oil pretreatment (Desalination) was tested using an enhanced mass transfer fiber membrane technology to investigate the influence of temperature, residence time, water injection rate, crude feed rate, and drainage recycle on desalination efficiency. The results were compared with the data of the oil from the third electrical desalter of industrial unit. It is clear that the desalting effect of membrane pretreatment technology has a certain advantage in desalination of heavy crude oil over the comparison object. Some suggestions are put forward for the application of membrane technology.

ANALYSIS OF FAULT OF CONVEYING CATALYST IN REGENERATOR STANDPIPE OF FCCU

2018, 49(5):  22-26. 

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Unsmooth catalyst transportation in the operation of the standpipe of the catalyst regenerator in 0.8Mt/a FCC unit of PetroChina Karamay Petrochemical Complex was found. The driving pressure in the standpipe and the pressure drop of the slide valve were both lower than the designed requirement, resulting in fluctuation of reaction temperature in the riser. Compared the axial pressure distribution in standpipe with the original design data, the results showed that no fluidized column was formed in the standpipe, and the pressure storage capacity is seriously insufficient due to the aeration orifices blockage and air rate insufficient, leading the catalyst bridging in the standpipe. By dredging the aeration orifices and adjusting the aeration rate, the conveying catalyst capacity of the standpipe can be improved to a certain extent.

OPTIMIZATION OF SOLVENT DEWAXING AND DEOILING PROCESS FOR HYDROTREATED HEAVY FRACTIONS

2018, 49(5):  27-30. 

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The dewaxing and deoiling processes using different solvent compositions, pre-dilution and cold point dilution were tested to investigate the optimal conditions for processing hydrotreated heavy fractions. Considering the dewaxing temperature difference, filtration rate, and the yield of dewaxing oil and deoiling wax, a filtrate recycling process with two dewaxings and two deoilings was proposed.

INDUSTRIAL APPLICATION OF CYCLONE SEPARATOR DIRECT CONNECTION TECHNOLOGY

2018, 49(5):  31-34. 

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There is a coking phenomenon in settlers of the 1.4 Mt/a catalytic cracking unit in Changqing Petrochemical Company, which restricts the unit for a long period operation. The analysis showed that the cyclone separator of the settler adopts a soft connection structure, leading to a leakage of oil and gas due to breathing effect. The long residence time of these oil and gas in settler is the fundamental cause of coking. In the technical transformation in 2016, the cyclone separator was changed from the soft connection to a direct connection, the second stage riser was canceled, and the mixed recycling oil and raw materials enter the first stage riser. The results showed that the settler is not longer coking, the operation elasticity is stronger, while no catalyst loss is observed when the pressure fluctuation of the direct connected settlers occurs, and the solid content in slurry meets the requirement. There is no oil and gas in the upper space of the settler and no obvious coking phenomenon. The yield of light oil increases 0.61 percent points, gasoline octane number improves 0.47, and the content of LPG increases 0.54 percent points.

DESIGN OF PARA-XYLENE COMPLEX USING LD PAREX TECHNOLOGY

2018, 49(5):  35-38. 

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The design of the first para-xylene complex using LD PAREX technology in the world was introduced in terms of material balance, unit capacity, operating conditions, process flow, and energy consumption and was compared with the traditional process. In the design, the heat integration center was raffinate column instead of xylene column and the desorbent rerun column was deleted; the flow scheme of hot high pressure separator plus cold low pressure separator was used for isomerization sector, the isomerization distillation and xylene separation sector was integrated optimally and the deheptanizer was canceled. The energy consumption per ton para-xylene was reduced from 7 964 MJ/t to 6 706 MJ/t, about 15.8%, due to relaxation of feed contaminant limit for adsorption separation unit and reduction of desorbent circulation quantity, which proves the LD PAREX technology advancement.

STUDY OF SULFUR DISTRIBUTION IN HYDROTREATED RESIDUE

Zhao Ning

2018, 49(5):  39-42. 

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At various LHSV and reaction temperatures，the hydrotreated residues with different sulfur contents were obtained using Maoming AR（high-sulfur residue）and Hainan RDS feed （low-sulfur residuum oil）as feedstocks. The sulfur distribution analysis showed that the changing rules of sulfur content in asphaltene are different with different sulfur contents in the hydrotreated oils. For Maoming AR，in the case of the sulfur content in the hydrogenated oil is not less than 0.31%，the lower the sulfur content in hydrotreated oil，the lower the sulfur content in asphaltene. For Hainan residue，when the sulfur content in the hydrogenated oil is not larger than 0.25%，the sulfur content in asphaltene becomes larger as reduction of sulfur content in hydrotreated product. The same variation tendency of the ratio of sulfur content in the asphaltene over the total sulfur content in the hydrotreated oil was observed: the lower the sulfur content in product and the greater the reduction of sulfur content, the higher the ratio of the sulfur content in asphaltene.

ADSORPTION SEPARATION OF CH4/N2 OVER METAL ORGANIC FRAME MATERIAL HKUST-1

Han Suying Han Xinhua Cao Yunxiang Gao Li Sun Daofeng Yan Zifeng

2018, 49(5):  43-48. 

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The HKUST-1 was obtained using trimesic acid self-assembly with Cu2+ and characterized by N2 adsorption，X-ray powder diffraction，TGA and SEM. Adsorption values of CH4 and N2 were measured by gas adsorption instrument. The Clausius-Clapeyron equation was used to calculate the adsorption heat of CH4. The separation coefficient of CH4/N2（SCH4/N2）was calculated by Ideal Adsorbed Solution Theory（IAST）. The results showed that HKUST-1 has a good adsorption effect on CH4. At conditions of 0 ℃，101.325 kPa and 25 ℃，101.325 kPa，the adsorption values of CH4 are 25.1 cm3/g and 15.2 cm3/g，the adsorption values of N2 are 8.0 cm3/g and 3.9 cm3/g，respectively. The selectivity factor for CH4 /N2 is 6.8，and the isosteric heat of adsorption of CH4 is about 20 kJ/mol. Compared with zeolite-like adsorbents，the isosteric heat was smaller，which meant a facile regeneration of adsorbents.

RELATIONS OF PAHs AND PCA CONTENT IN ECO-FRIENDLY HYDRTREATED RUBBER OIL

2018, 49(5):  49-54. 

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The relations of PAHs and PCA content were studied in order to produce environmental-friendly rubber filling oil with CA value over 12% by hydrotreating process. The rubber oils were made using different feedstock, hydrotreating catalysts under process conditions. The PAHs and PCA contents were determined for each product. The results showed that the PAHs can meet the requirements of EU environment protection laws and regulations when the PCA content is less than 3%, however, the PCA content meets the standard if and only if the content of PAHs is below 1.0 ?g/g or not detected; in addition, the operation range (reaction temperature) is wider than that of PCA when PAHs were regarded as controlling index. The relations of PAHs and PCA was established, yPAHs=0.036 3 xPCA3.186 6 with R of 0.9822 and can be used to predetermine the PAHs content from PCA data.

RECYCLING METAL CONTAMINATION AND AGING METHOD FOR SIMULATING METAL AGE DISTRIBUTION OF FCC EQUILIBRIUM CATALYST

Fei Ren

2018, 49(5):  55-59. 

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The effects of the pretreatment methods of cyclic contamination-oxidation-reduction cycle and traditional impregnation contamination-100% water vapor aging on the performance of FCC catalysts were compared. The characteristics of metal distribution on the catalysts prepared by the two pretreatment methods as well as FCC ECat were investigated by means of optical microscopy and electron probe microscope analysis. The experimental results showed that the product distribution of the two types of aged catalysts is different when the microactivity is comparative. The product distribution of catalyst prepared by the cyclic contamination aging method is good, close to the level of ECat. The aged catalyst prepared by traditional method have no metal age distribution, while metals on circulating pollution aging catalyst have age distribution and is close to ECat.

DEVELOPMENT OF NH3 SELECTIVE CATALYTIC REDUCTION CATALYST WITH NEW MICROFIBER STRUCTURE

2018, 49(5):  60-65. 

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Aluminum fiber supported Cu-ZSM-5 and Cu-SSZ-13 catalysts with novel micro-fiber structure for NH3 selective catalytic reduction (NH3-SCR) were prepared. Due to the micro-fiber monolithic catalyst has a unique three-dimensional network structure and large porosity; it can improve the mass transfer ability and dispersion of active components. The results of activity evaluation indicated that compared with pure molecular sieve catalysts，the two kinds of micro-fiber monolithic catalysts exhibit superior catalytic activity and sulfur resistance. The results of dynamic calculation indicated that the kinetic constant of microfiber monolithic catalysts is larger than that of pure molecular sieve catalysts and is the kinetic reason for the higher activity of micro-fiber monolithic catalysts. This study presents huge potential in the field of NH3-SCR.

STUDY ON PREPARATION AND LUBRICATION PERFORMANCE OF ENVIRONMENTALLY FRIENDLY SYNTHETIC CUTTING FLUID

Hua Jie TANG Sun Jianlin

2018, 49(5):  66-70. 

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The synthetic cutting fluid was prepared using oleic acid and triethanolamine ( mass ratio of 1.8) at 60℃. The stability analysis, four-ball test, corrosion experiment, and cutting test were conducted to evaluate the performance of the product. The highest PB of the cutting fluid is 784 N, and the diameter of the wear scar spot is 0.540 mm, and the single - piece rust resistance time is 96 h. The results showed that the water temperature has a significant influence on the transparency, stability and extreme pressure performances of the cutting fluid, but has little effect on the anti-wear and antifriction properties.

ALKYLATION OF NAPHTHALENE CATALYZED BY TRIFLUOROMETHANESULFONIC ACID

2018, 49(5):  71-74. 

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Using trifluoromethanesulfonic acid as catalyst for naphthalene alkylation was studied. The effects of catalyst dosage, temperature, the ratio of naphthalene and α-olefin, dropping time on the alkylation of naphthalene and the oxidation stability of alkylated naphthalene were investigated. The results showed that under the reaction conditions of a naphthalene/1-dodecene mole ratio of 1:3, a reaction temperature of 80 ℃, a dropping time of 3 h and a reaction time of 1 h, the kinematic viscosity of the alkylate is 16.35mm2/s at 100℃, the conversion reachs 96%. At the same time the bromine index is 168gBr2/(100g). No need to further hydrorefining process. The high pressure differential scanning calorimetry（PDSC）experiments showed that the antioxidant stability of PAOs increases with the addition of certain amount of alkylated naphthalene.

EFFECT OF POUR POINT DEPRESSANT ON NON-ISOTHERMAL CRYSTALLIZATION BEHAVIOR OF WAX IN CRUDE

2018, 49(5):  75-79. 

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A pour point depressant (PA-EVA) was prepared by using ethylene-vinyl acetate copolymer (EVA) and higher alcohol acrylate (PA) as raw materials. Its effect and mechanism on Nanyang crude oil were studied. The effect of pour point depressant on non-isothermal crystallization behavior of wax was investigated by differential scanning calorimetry (DSC). Results showed that the nucleation of PA-EVA increases the peak crystallization temperature and enhances the crystallization rate of the wax. PA-EVA improves the flow ability of crude oil by increasing the wax crystal geometry size, reducing the coating of liquid oil.

EFFECT OF NA2S ON STABILIZING HEAVY METALS IN BIOCHEMICAL RESIDUAL SLUDGE

Chao ZHANG

2018, 49(5):  80-84. 

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Stabilizing heavy metals for sludge harmlessness is of great significance. The results of ICP and Tessier analysis of heavy metals in biochemical residual sludge of a certain refinery showed that the contents of Ni, Cu, Pb, Zn, Ba, Cr, Cd, Ag, As, and Hg are high, and these metals exist in five different forms; Na2S has a good stabilizing effect on these heavy metals from the unstable state into the steady state, so that the leaching concentration of heavy metals from the sludge reaches the requiremene of the national standard on solid waste.

REMOVING VOCs AND ODOUR FROM WASTE WATER AND GAS IN SEWAGE TREATING PLANT

2018, 49(5):  85-91. 

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VOCs and odour waste gas from refinery sewage treatment plant can be divided into two types: high-concentration waste gas, among which the non-methane hydrocarbon concentration (NMHC) is 500 - 40 000 mg/m3, total gas flow rate 1 000 - 10 000 m3/h ), is from waste-water lifting tank, water homogenizer, oil separator, flotation tank, waste oil tank; low-concentration waste gas (NMHC 10～300 mg/m3, gas flow 20 000 - 50 000 m3/h) is from aeration tank, oxidation ditch and sludge dewatering process. Technologies SWAT-1 and SWAT-2 were developed by Fushun Research Institute of Petroleum and Petrochemicals (FRIPP) to treat high-concentration and low-concentration exhaust gas from refinery wastewater treatment plants. In SWAT-1, high-concentration waste gas from oil separator, flotation tank is treated by “desulfurization and total hydrocarbon concentration homogenization-catalytic oxidation ”process; the low concentration exhaust gases from aeration tank are treated with "scrubbing - adsorption" process, and the saturated low concentration exhaust gas adsorbent is regenerated by the hot gas from catalytic oxidation and then returned to catalytic oxidation treatment process. In SWAT-2, high-concentration waste gas is treated by “low temperature diesel absorption-desulfurization and total hydrocarbon concentration homogenization-catalytic oxidation” process. By SWAT-1 and SWAT-2 technologies, NMHC of purified gas is less 50 mg/m3 and the minimum is less than 10 mg/m3, and the concentration of benzene, toluene and xylene is less than the detection limit, and the odor concentration is less than 20 (non dimensional)

EXPERIMENTAL STUDY OF ONLINE BLENDING TECHNOLOGY FOR RESIDUAL MARINE FUEL OIL

2018, 49(5):  92-96. 

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In view of the requirements of online blending process for marine residue fuel oil，a residue dilution model and a marine fuel oil online management system were developed with a new efficient static mixer. A residual fuel oil online blending process was developed. An online mixing test device with capacity of 240 L/h was established. The operation test showed that the equipment was running smoothly，which can realize the whole process, including blending scheme generation，continuous production automatic control，product performance real-time feedback. All national standard marine residue fuel oil can be produced by this process and the product has a good stability.

NUMERICAL SIMULATION AND STRUCTURE OPTIMIZATION OF DISTRIBUTOR IN HYDROGENATION REACTOR

2018, 49(5):  97-102. 

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The hydrodynamic performance of the bubble distributor in hydrogenation reactor was simulated by Fluent software. The downcomer and the stream breaker of the BL gas-liquid distributor. were optimized in structure. It was found that the spray area increases by 255% and the non-uniformity reduces by 30.19% after optimization, but the pressure drop of the improved distributor is 73.63% higher than the BL type distributor. The results indicated that the comprehensive performance of the new distributor is better than the prototype.