In response to the insufficient heat ex-change capacity of the fractionation top circulation system of the fractionation column in the 2.2 Mt/a catalytic cracking(DCC-plus)unit of Daxie Petro-chemical Co Ltd,CNOOC,even if the cold reflux pump ran at full load,there were still problems such as the high thermal load on the top of the fractiona-tion column,the excessive pressure drop at the top of the fractionation column,and even frequent exceed-ing of the dry point of crude gasoline.So the thermal joint utilization technical transformation was carried out on the DCC-plus unit and the gas separation unit.The results showed that after the transformation and operation optimization,the fractionation column ba-sically reached the optimal operating state.Not only did the dry point of crude gasoline meet the stan-dard,but also significantly decreased,and its opera-tion was stable and controlled at 177-185℃.More-over,the top circulation return temperature of the fractionation column was controlled at 105.2℃,which effectively slowed down the corrosion environ-ment of HCl-H2S-H2O and dew point corrosion of the top circulation heat exchanger.Comparing with that before the technical transformation,the cold return flow rate at the top of the fractionation column de-creased by 36.7%,and the number of overhead air coolers and cold reflux pumps in operation decreased by 6 and 1 units,respectively,which effectively avoided the potential system safety hazards when they ever all had to be running at full load in each high temperature summer season before.Moreover,the total consumption of low-temperature hot water in the gas separation unit reduced by 84.8 t/h.
The evaluation experiment was con-ducted on the catalytic cracking of different compos-ite light hydrocarbon raw materials to produce low-carbon olefins under the catalysis of A type dedicated catalyst on the 40 L fixed fluidized bed reactor to in-vestigate the effects of process conditions on raw ma-terial conversion rate,ethylene&propylene selectiv-ity and yield,molar ratio of propylene to ethylene,and the by-product yield of mixed C4 hydrocarbons,hydrogen and methane.The results showed that with the total yield of diolefins as the indicator,the catalytic cracking performance of light hydrocarbon raw materials to produce low-carbon olefins was ranked from high to low as follows:n-alkanes,isoalkanes,cycloalkanes and aromatic hydrocarbons.Adding isooctane to the light hydrocarbon raw mate-rial R could significantly improve the conversion rate of light hydrocarbon raw materials and the molar ratio of propylene to ethylene in the product during catalytic cracking,but the yield of ethylene&propy-lene and the total yield of diolefins in the product were slightly reduced.The optimal reaction condi-tions for catalytic cracking of light hydrocarbon raw material R with the addition of 10%(mass fraction)isooctane to produce low-carbon olefins with A type dedicated catalyst were as follows:the liquid space velocity at 0.64 h-1,the flow rate of nitrogen and the stripping water at 0.50,1 L/min respectively,the re-action temperature at 665℃,and the reaction pres-sure at 40 kPa.Under the above optimal conditions,the conversion rate of the composite light hydrocar-bon raw material was 80.11%,the total yield of di-olefins and the ethylene&propylene yield in the tar-get product were 50.03%and 43.50%,respectively,and the molar ratio of propylene to ethylene was 0.73.
The comprehensive analysis was con-ducted on the technological progress,industrial de-velopment status,production costs,and economy of coal to natural gas at home and abroad.The main problems in the development of China's coal to natu-ral gas industry were analyzed and considered,and the relevant suggestions were proposed.The conclu-sion was that China had basically mastered the key core technologies of the entire coal to natural gas in-dustry chain,and had made the significant progress in industrial development.However,there were also some problems that could not be ignored,mainly in-cluding:the excessive project planning,limited pro-duction,and risks and challenges in technology,en-vironmental protection and safety,so it was necessary to continue to promote the demonstration operation of industrial devices and technological progress.The e-conomy of projects'operation was not strong and the production costs was high,so it was necessary to fur-ther reduce costs and improve their market competi-tiveness.Their resource allocation,pipeline network access,and market access acceptance were low,and it was necessary to make efforts to promote the coor-dinated development with traditional natural gas.Due to the large CO2 emissions in their production process,so it was necessary to strengthen the appli-cation of CCUS(CO2 capture,utilization and storage)technology and the introduction of green hydrogen,promote carbon cycle and"zero carbon"emissions,and boost the large-scale development of coal to nat-ural gas industry.
In response to the situation of the short-age of raw materials supply for reforming units,as well as the surplus catalytic gasoline and the sluggish sales market,the technological transformation of catalytic hydrogenation gasoline cutting into mid-range fractions(75-165℃)and prehydrogenation refining process were carried out in the 600 kt/a aromatization unit of Zhongjie Petrochemical Co Ltd,CNOOC,then the blending was supplemented to re-forming raw materials to ensure the aromatic hydro-carbon production with greater economic benefits.The operation and calibration results showed that the content of sulfur,nitrogen,olefins and arsenic in the catalytic gasoline produced by the maximizing iso-paraffins(MIP)process was significantly higher than that of straight run naphtha,so it could not be direct-ly blended as the continuous reforming feedstock.After the technological transformation,the distilla-tion rate of the mid-range catalytic gasoline cut frac-tion in the new cutting tower was 75.1%,and the blending proportion to the mixture of continuous re-forming feed in the new prehydrogenation reactor was 25.4%,and its potential aromatic mass fraction was 3.6 percentage points lower than that of full straight run naphtha.Under 74%load of the mixed feed of reforming unit,the potential aromatic mass fraction of hydrotreated naphtha product was 41.0%.Com-pared with the relevant design indicators of main products,the mixed xylene yield increased by 1.64 percentage points,yet the yield of benzene,toluene,the mixed C≥9 heavy aromatouldics and the total aro-matics decreased by 0.84,0.34,2.50,2.04 percent-age points,respectively.Not only could the high load operation of the continuous reforming unit and the production of well-selling aromatics be solved expe-diently in the case of under the situation of insuffi-cient supply of straight run naphtha feedstock,but also helped to maximize the unit economic benefits under the situation of depressed sales market of catalytic gasoline products.
The research progress on selective catalytic reduction(SCR)denitrification catalysts deriving from Cu,Mn and other based hydrotalcite-like composite oxides(LDO)was reviewed.And the effects of preparation methods,metal modifications,and carrier types on the denitrification efficiency,ac-tivation temperature and water and sulfur resistance of such catalysts were emphatically analyzed.Final-ly,it was pointed out that the future research&de-velopment directions of such LDO catalysts were:to improve the water and sulfur resistance of the cata-lysts by cladding,doping,and other methods;to pre-pare the molding catalysts suitable for large handling capacity via using the methods such as coating and integrated extrusion.
In response to the situation that the price of pure benzene in the market was higher than that of p-xylene and toluene in recent years,Liaoyang Petrochemical Company,PetroChina developed a new disproportionation catalyst LYT-1 to produce benzene with high yield by using the aromatics/toluene disproportionation technology and the new molecular sieves combined with metal active compo-nents as raw materials.This new catalyst was suitable for the raw material conditions of the pure toluene or the traditional disproportionation under the mass ratio of toluene to C≥9 aromatics at 9.0,and it was put into the first industrial application in the 480 kt/a dispro-portionation unit.The calibration results showed that the new LYT-1 catalyst had the good adaptability and operational stability under the operation conditions of the reaction temperature at 370℃,the reaction pressure at 2.50 MPa,the molar ratio of hydrogen to aromatics at 4,the mass space velocity at 2.5 h-1,and the disproportionation raw material of m(toluene)/m(C≥9 aromatics)at 9.0,the toluene conversion rate and benzene product selectivity were 51.19%,42.20%in average respectively.Compared to the tra-ditional disproportionation catalyst BHAT-1 used in this above same unit,its toluene conversion rate and benzene selectivity increased by 9.15,2.11 percent-age points,respectively.
The research progress on dual-riser fluid catalytic cracking technology at home and abroad was reviewed,including the domestic flexible dual-riser fluid catalytic cracking(FDFCC)series technology,the enhanced deep catalytic cracking(DCC-plus)technology,the two-stage riser catalytic cracking for maximizing propylene(TMP)technolo-gy,and the foreign Maxofin-FCC process,PetroRiser process and PetroFCC process.Then the dual catalyst partition regeneration technology was emphatically introduced,which aiming to solve the problem of precise matching between catalyst and feedstock.It was pointed out that the future research&develop-ment of such dual catalyst partition regeneration pro-cess technology should pay attention to the following aspects:further optimize the process parameters of the dual-riser catalytic cracking partition regenera-tion unit so as to reduce the difficulty of operation;the different technical solutions could be flexibly switched on the same device according to market de-mand,so as to speed up the industrialization process.
Firstly,Spyro software was used to model the operation of naphtha cracking furnace in the 1 Mt/a ethylene plant of a company,and the his-torical production data was applied to correct the de-viation of cracking furnace outlet temperature(COT)and coking rate,and the simulation results were veri-fied to be reliable.Then the effects of operating con-ditions on the product yield,coking thickness,and operating period of the naphtha cracking furnace were simulated and analyzed.The results showed that COT had the significant impact on the operating pe-riod and product yield of naphtha cracking furnace in comparison to the dilution ratio and feedstock flow.When the current COT of the 2#naphtha cracking furnace appropriately increased from 838.3℃ to 841.6℃,the ethylene yield increased by 0.16 per-centage points,meanwhile the changes of coking,TMT(surface temperature of cracking furnace tube)and other factors affecting the operating period of the cracking furnace were under control.The optimized operating model could be used to predict the operat-ing period of the naphtha cracking furnace and pro-vide the simulation analysis guidance for relevant operation optimization.
In order to reduce the energy consump-tion in the refrigeration device area and ensure that the maximum heat transfer temperature difference of the main cold box was lower than 25.00℃,the chemical steady-state process simulation software Aspen Hysys V10 was used to model the mixed re-frigerant circulation cooling(MRC)system of the 10.9 kt/a natural gas light hydrocarbon removal unit of Oil and Gas Co Ltd of Changqing Oilfield(Yulin),PetroChina,and the cold-heat compound curve of the main cold box was constructed after simulation.Then the multi-parameter sensitivity analysis and optimization were carried out.The re-sults showed that the optimal values of the tempera-ture of the refrigerant separator and the high-pres-sure refrigerant flow rate of the main cold box related to the key control parameters of the MRC system were 1.75℃ and 64 960.00 m3/h respectively,and the optimal inlet and outlet pressure of the refrigerant compressor were 270.00,2 940.00 kPa,respectively.Comparing with that before optimization,under the optimal operation conditions,the maximum heat transfer temperature difference in the main cold box was 23.47℃ by the decrement of 2.37℃,and the energy consumption in the refrigeration device area was 5799.17 kW by the reduction of 28.01%.
Aiming at the coking problem of the spiral plate heat exchangers of 2.6 Mt/a fluidized-bed residue hydrogenation unit in a certain refining and chemical company,in which the bottom residu-um of the vacuum tower was exchanged with crude oil,the improvement measures on heat exchangers anti-coking were put forward on the basis of the analysis of the composition of the residuum and the coke in the above heat exchangers.The results showed that the main component of residual oil was C element,the main composition of coke was the aro-matic compounds and a small amount of alkane,car-bon powder and other inorganic substances in the spiral plate heat exchanger.The flow path of residual oil in spiral plate heat exchanger was adjusted from small inner flow path to large outflow path,which delayed the polymerization time of asphaltene,col-loid and other coke,and prolonged the running peri-od of heat exchanger.Two heat exchangers were switched in parallel to carry out on-line cleaning by measuring and monitoring the total heat transfer co-efficient or pressure drop of the heat exchanger and using heavy aromatics as coke cleaning agent,the long operation period of the heat exchanger could be realized.
Using an ideal trimethylbenzene mix-ture system as a model in the isomerization of 1,2,4-trimethylbenzene to 1,3,5-trimethylbenzene,the thermodynamic equilibrium composition of mixed trimethylbenzene at different temperatures and the conversion rate of 1,2,4-trimethylbenzene,the se-lectivity and yield of 1,3,5-trimethylbenzene within the reaction temperature range were obtained through the thermodynamic calculations.The isomerization reaction was carried out by HZSM-5 catalyst modi-fied with Ag and its performance for the isomerization was evaluated in a pressurized fixed bed reactor.The process conditions of reaction temperature,reaction pressure,mass space velocity,and Ag addition mass fraction were optimized.The results showed that n(1,2,3-trimethylbenzene)∶n(1,2,4-trimethyl-benzene)∶n(1,3,5-trimethylbenzene)was 0.052∶0.674∶0.274 in the average thermodynamic equilibri-um composition of mixed trimethylbenzene.The con-version rate of 1,2,4-trimethylbenzene was 32.6%,the selectivity and yield of 1,3,5-trimethylbenzene were 75.6%and 27.4%respectively within the reac-tion temperature range.The conversion rate of 1,2,4-trimethylbenzene was 33.80%,and the selec-tivity of 1,3,5-trimethylbenzene was 71.34%,and the highest one-way yield of 1,3,5-trimethylben-zene could reach 24.90%under the optimized condi-tions of the reaction temperature at 280℃,the reac-tion pressure at 1.6 MPa,and the mass space velocity at 1.0 h-1,Ag addition mass fraction at 1%,and the molar ratio of hydrogen to oil at 5.
Using furfural as the extraction&sepa-ration solvent and the circulating oil of the 1 Mt/a fluid catalytic cracking(FCC)unit of Karamay Petrochemical Co Ltd,PetroChina,as the raw mate-rial,the cases of extraction,separation and refining pretreatment of the thick polycyclic aromatic hydro-carbons with short side chains and the saturated hy-drocarbons with few long side chains in FCC circu-lating oil were investigated in the laboratory.The re-sults showed that under the optimal pretreatment conditions of the extraction temperature at 60℃,the mass ratio of furfural to FCC circulating oil at 2∶1 and the residence time at 30 min,the extraction pretreat-ment effect of FCC circulating oil was better,and the ash was completely removed.After FCC circulating oil was optimally refined by furfural extraction pre-treatment,the mass fraction of the aromatics of hy-drocarbon group composition and the total aromatics of hydrocarbon composition both in the extract oil was up to 80.35%and 79.1%,respectively,which could be used as the high-quality raw materials for preparing the spinnable mesophase asphalt.Mean-while,the density,sulfur and nitrogen content of the raffinate oil were significantly lower than that of FCC circulating oil.The mass fraction of saturated hydro-carbon in hydrocarbon group composition was as high as 91.45%,and the sum of the mass fraction of satu-rated naphthene and paraffin in hydrocarbon compo-sition reached 93.9%.Therefore,the raffinate oil had the satisfactory catalytic cracking performance and could be returned as the high-quality raw materials for FCC unit.
The Na/K-FER mo lecular sieve syn-thesized by crystal seed induction and NH4Cl solu-tion were used to prepare the pentene isomerization molecular sieve catalysts by the microwave-assisted ion exchange method.Compared with the traditional hydrothermal exchange method,the effect of ion ex-change conditions on the performance of the molecu-lar sieve was investigated,and its catalytic perfor-mance for pentene isomerization of post-ether C5 raw material was evaluated.The results showed that the crystal surface of Na/K-FER molecular sieve growed intact and had good crystallinity.Compared with the hydrothermal ion exchange method,the microwave-assisted method could improve the exchange effi-ciency of Na+ and K+ in molecular sieves.Under the conditions of the reaction temperature at 300℃,the reaction pressure at 0.3 Mpa and the mass space ve-locity at 3.0 h-1,the prepared pentene isomerization catalyst could operate stably for 720 h,the conversion rate of n-pentene and the selectivity of isopentene was greater than 50%,95%,respectively.
Aiming at the problem that the tower top temperature frequently exceeded the design index of 65℃ and abnormally fluctuated wildly during the operation of the stabilization tower of the 250 kt/a fixed bed semi-regenerative catalytic reforming unit,which resulted in the volume fraction of C5 compo-nents in the liquefied petroleum gas(LPG)product far exceeding the index of not more than 5.0%,the causes were analyzed and the corresponding mea-sures were implemented.The results showed that:once the nitrogen content in refined naphtha re-mained high frequently,the nitride impurities would generate NH3 during the reforming reaction,when encountering HCl formed by the hydrolysis and loss of chlorine in the active component complex of the chlorine-promoted reforming catalyst in the system under the humid environment,they would combine and generate a large amount of NH4Cl,which would crystallize below 220℃ and be insoluble in the re-forming oil.Then such NH4Cl carried other solid im-purities in the system and further crystallized and sedimented,finally resulting in the ammonium salt blockage&corrosion of the equipment and its acces-sories.On the premise that the reforming unit was not shut down,the trays and float valves of the stabiliza-tion tower blocked by ammonium salt were cleaned by the on-line injection of the deoxygenated water(its dissolved oxygen content not more than 15 μg/L).By doing so,the mixed NH4Cl crystal sediments were effectively removed,the separation effect of the stabi-lization tower tray could be restored and improved,and the quality of LPG product and the stable,long-term operation of this unit could be ensured.
The mechanism model of atmospheric and vacuum distillation unit was established by using Petro-Sim process simulation software developed by KBC Company in Britain.Then the optimum operat-ing conditions of the combined 3.0 Mt/a atmospheric and vacuum distillation unit was simulated and opti-mized during producing road asphalt.The results showed that the material separation accuracy of this combined atmospheric and vacuum distillation unit could be improved by increasing the stripping steam injection capacity at the bottom of the atmospheric tower and optimizing the heat recovery by reflux in the middle section of the vacuum tower.After the simulation and optimization,when the outlet temper-ature of atmospheric furnace reduced from 358.0℃ to 347.0℃,the outlet temperature of vacuum furnace increased from 375.0℃ to 398.0℃,which trans-ferred part of the processing load of atmospheric fur-nace to that of vacuum furnace.In this way,not only caused the actual processing capacity of Merey crude oil in this combined unit increase from 272.30 t/h to 357.60 t/h,which reached the original designed pro-cessing capacity requirements,but also the yield of naphtha,mixed diesel oil and road asphalt in the products increased by 31.01%,51.21%and 30.52%in turn,however the yield of mixed wax oil changed little,but the comprehensive economic benefit of this combined unit increased by 4.479 million yuan per month.
The corresponding solid acid catalyst was prepared by impregnating p-toluene sulfonic acid(p-TSA)onto 4 different silicon-based carriers(SiO2,SiO2-La2O3,SBA-15 and Silicalite).The cat-alysts were characterized by methods of X-ray diffraction,physical adsorption,Fourier transform infrared spectrometer and elemental analysis.Com-paring with the liquid acid p-TSA catalyst,the effect of the support on the catalytic performance of solid acid catalyst was investigated by Prins reaction of formaldehyde and ethylene.The results showed that the larger specific surface area and pore size of sili-con-based carrier,the better dispersion of p-TSA.p-TSA was more evenly dispersed on SiO2 and SBA-15 surfaces.The B acid content of solid acid catalyst obtained with SiO2 as the carrier was higher.The catalytic performance of solid acid catalyst was better than that of liquid acid p-TSA catalyst when the amount of p-TSA was the same.When the loading of p-TSA was at 55%and the solid acid p-TSA/SiO2 with SiO2 as the carrier was used as the catalyst,the formaldehyde conversion rate,1,3-dioxanocyclic yield and selectivity were the best,which were 87.73%,20.81%and 23.73%,respectively.
Aiming at the continuous and slow de-crease in the UV transmittance(UV value)of mo-noethylene glycol(MEG)products during full load operation of the 0.1/0.7 Mt/a ethylene oxide(EO)/ethylene glycol(EG)unit of Fujian Gulei Petro-chemical Co Ltd,the relevant influencing factors and reasons were analyzed,and the corresponding coun-termeasures were implemented.The results showed that the countermeasures were as follows:standard-ized and optimized MEG sampling&analysis pro-cess,and ensured timely sampling&analysis within 1 h after sampling;Reduced pH value of EO stripper and stably controlled at 5.5-7.0;Reduced EO reac-tion temperature from 235.25℃ to 229.67℃;Timely did the bubbling®enerating operation for the an-ion&cation exchange resins of the water treatment unit for 3 h;Decreased the mass fraction of formalde-hyde in the side line of MEG tower from 109×10-6 to 59×10-6 during full load operation.After the opti-mization and implementation of the above counter-measures,the selectivity of silver catalysts increased from 84.5%to 86.0%,and the UV value of MEG products increased from 92.3%to 94.7%under the 275 nm ultraviolet light.
采用动态交联技术制备了环氧类玻璃高分子材料(EPV),将其制得的片材在不同模压条件下进行重复加工,考察了模压温度、模压时间和模压压力对EPV回收材料性能的影响.结果表明:重复加工没有造成EPV回收材料的降解;模压温度越高,模压时间越长,模压压力越大,越有利于EPV的愈合和重塑;在模压温度为180℃,模压压力为20 MPa,模压时间为10 min的较佳条件下,重复加工的EPV回收材料力学性能与初始EPV片材的接近.
在小型提升管中试装置上,通过催化裂化反应-再生循环试验,考察了富氧燃烧再生应用于催化裂化装置的可行性,并从催化剂孔结构和酸性角度揭示了再生气体组成对反应规律的影响.结果表明:催化裂化再生过程采用富氧燃烧再生代替常规空气再生,在烧焦效果和裂化反应方面均可行,不会对反应产物和装置平稳运行产生不良影响;富氧燃烧再生过程需要关注高浓度CO2 气氛对再生床层温度的影响;相同氧浓度条件下,富氧燃烧再生效果与空气再生效果一致,并且氧浓度与再生效果、反应转化率呈正相关;通过调节再生气体组成,可以灵活调节再生器的烧焦效率、烧焦负荷以及加工能力,提高装置的整体经济性;富氧燃烧再生技术既能提高装置操作灵活性,又能实现催化裂化装置的CO2 捕集.
分别以B,C型硅胶为固体硅源合成ZSM-5 分子筛,采用X射线衍射仪、X射线荧光光谱仪、扫描电子显微镜、比表面和孔径分布测定仪、化学吸附仪对 2 种ZSM-5 分子筛进行表征,并对 2 种分子筛制成的催化裂化催化剂的催化性能进行评价.结果表明:2 种分子筛相对结晶度均达到了 90%以上,离子交换不会影响分子筛的晶相;以C型硅胶为固体硅源制得的分子筛(C-HZSM-5)的总比表面积为 366.17 m2/g;当C-HZSM-5 用于催化剂成分时,原料油转化率比以B型硅胶为固体硅源制得的分子筛(B-HZSM-5)低 1.4 个百分点,但丙烯收率高 0.16 个百分点;当C-HZSM-5 用于助剂成分时,液化气收率比B-HZSM-5高 1.52 个百分点,丙烯收率高 0.91 个百分点.
