Study On The Law Of Mixing Different Kinds Of Deoiled Asphalt With Delayed Coking

In order to complete the transformation and upgrading work,liaohe petrochemical company plans to build a new solvent deasphalting device in the"14th five-year plan",which is expected to produce 300,000 to 400,000 tons of deasphalting asphalt every year.In addition to some blended road asphalt,there is still 150,000 to200,000 tons of deasphalting asphalt with no way out.Now it is proposed to adopt the method of mixing deoiled asphalt with delayed coking unit to solve this part of deoiled asphalt.In this paper,conventional petroleum analysis methods,infrared,X-ray fluorescence spectrum,thermogravimetry,gel permeability chromatography,nuclear magnetic analysis and other analytical methods were used to analyze ultra-heavy oil deoiling asphalt,large-mixed oil deoiling asphalt,liaohe super-heavy oil and coking raw materials mixed with different proportions of ultra-heavy oil deoiling asphalt or large-mixed oil deoiling asphalt.It was found that compared with liaohe super heavy oil,the density and carbon residue of super heavy oil deoiling asphalt and large mixed oil deoiling asphalt were relatively large,with high aromaticity f _A value,low naphthenic carbon fraction f _N and alkyl carbon fraction f _P values,and easy to condense coke.In addition,the density,average molecular weight,saturation and colloid of mixed raw materials are additive,while viscosity,carbon residue,aromatic content and asphaltene are not.It provides basic data for predicting the properties of this kind of oil mixture.In accordance with 7.5%,15%and 22%proportions,the ultra-heavy oil deoking asphalt or large-mixed oil deoking asphalt is evenly mixed with liaohe super-heavy oil,and the coking test is carried out in the micro-reactor to analyze the relationship between raw material properties,reaction conditions and coking.The results show that the coke yield of the mixed raw materials mixed with super heavy oil deoiling asphalt or large mixed oil deoiling asphalt is about 21-24 times of its density,1.5-1.8times of its carbon residue value,0.45-0.5 times of(colloid+asphaltene)content,and0.7-0.9 times of aromaticity(f _A).The coke rate and coke tendency of raw materials can be estimated roughly according to the above rules.With the increase of the mixing ratio of deoiled asphalt,the reaction time is prolonged and the reaction temperature is increased.Response surface analysis(RSM)was used to obtain the relationship between the properties of raw materials(mixing ratio),reaction temperature and reaction time and coke generation rate.The mixed raw material mixed with 15%deoiled asphalt was put into the kettle coking unit for coking reaction.The results show that the yield of coking gas and coke increases,the yield of gasoline decreases,the yield of diesel oil and wax oil increases,and the yield of total liquid decreases.After blending and refining the deoiled asphalt,the coke specification is reduced from 2A to 3A.Coking reaction was carried out by mixing 15%oil-deoiling asphalt as raw material.The effects of coking time and temperature on product distribution were investigated.The results showed that the liquid yield decreased and coke yield increased with the increase of reaction time and reaction temperature.For the mixed raw materials mixed with 15%of the deoiled asphalt,the suitable coking reaction conditions are 480?and 6 h.