مطالعه آزمايشگاهي و توسعه يك مدل سينتيكي براي واكنش هاي كراكينگ حرارتي ته مانده هاي سنگين پالايشگاهي

چكيده انگليسي :

Abstract In this research first the analysis of selected vacume residues VRs from Iranian refineries andtheir blend binary samples were measured In continue from selected VRs and their binaryblend samples the final product yields were measured in laboratory set up at 400 500 C andthe products were identified as gas C1 4 distillate C5 500 C and coke remain solid in thereactor and toluene insoluble Two groups of correlations were developed to predict finalproduct yields In one group correlations were linear functions of CCR Conradson CarbonResidue and temperature and in another group they were linear functions of CCR and powerlaw from temperature The results showed that the correlations with power law functions fromtemperature have more precission than another ones Also the results showed that byincreasing 15 C the amounts of distillate yield more than 2 wt uncreases and coke yieldreduces less than 1 wt Beside in constant temperature by increasing 1 wt in CCR value the amounts of distillate yield reduces more than 2 wt and coke yield increasemore than 1wt Moreover from three selected Iranian VRs that have especial characteristics and theirblend samples the kinetic tests were carried out at three temperatures 420 450 and 480 C andfour residence times 10 30 50 and 120 min Two kinetic models with four and five lumpeswere proposed to predict product yields and un converted feed values In four lumps kineticmodel feedstock was considered as a unit lump and products gas C1 4 distillate C5 500 C and coke Insoluble solid pahse in toluene were considered in three seoarated lumps In fivelumps kinetic model feedstock and products were considered in similar four lumps kineticmodel but an especial lump that named meso asphaltene was considered between feed andcoke lumps Both models showed that by increasing of CCR value the activation energies ofthe reactions increase and decrease their rate constants Their values were reported 7 9 19 22 and 12 14 kCal mol for gas distillate and coke respectively Furthermore threecorrelations were developed to predict coke induction period in delayed coking processes Firstmethod was based on experimental results and others were based on kinetic rate constants ofdeveloped four and five lumps kinetic models The results showed that in the method based onexperimental results by increasing of temperature or reducing of CCR value the cokeinduction period reduces exponentially and reported 11 19 2 8 and 1 3 minute for 420 450 and 480 C repectively The method based on four lumps kinetic model showed that cokeinduction period reduces by increasing the total rates of coke and distillate production or redungof the feed fraction content that can produce only light gas Also the method based on fivelumps kinetic model showed that this time reduces by reducing the most meso asphaltenecontent CCR reducing and needed time to reach it rising temperature Also the precission ofall methods were studied by using a similar feed at different temperatures The results showedthat the method based on experimental results has the least error 15 w and then the methodbased on five lumps kinetic model has lower error 20 w The method based on four lumpskinetic model has higher error 20 w The results confirm that coke is produced from mesoasphalte and while it reaches to its maximum value in the reaction the primary coke particlesare formed Also the values of average relative error boost powerly by increasing temperature Keywords Vacuum Residue Delayed Coking Kinetic Model Coke Induction Period

ترابي اصفهاني، فرشاد

مطالعه آزمايشگاهي و توسعه يك مدل سينتيكي براي واكنش هاي كراكينگ حرارتي ته مانده هاي سنگين پالايشگاهي

ته مانده نفتي , كك سازي تاخيري , مدل سينتيكي , زمان آغاز تشكيل كك