【作者】 隆建；

【导师】 沈本贤；

【作者基本信息】 华东理工大学 ， 化学工艺， 2012， 博士

【摘要】 提高劣质油生产轻质油品和化工原料的收率,是节油增效的主要途径。溶剂脱沥青(SDA)是重油轻质化的重要途径之一,但工艺操作中存在“脱沥青油(DAO)在质量上能满足催化裂化(FCC)进料要求时收率低、收率高时性质变差而不符合FCC原料标准”的矛盾关系。为充分利用现有的SDA装置和技术,使劣质减渣(VR)中轻组分更多进入到DAO中,沥青质、重金属以及部分硫、氮化合物得以有效地脱除,增加DAO收率并确保其质量满足二次加工要求,在高油价和严格的环保要求以及“缺油、少气、富煤”资源特征下,开发油煤结合相关技术是一个值得重视的方向。本文对劣质减渣掺炼高温煤焦油(CT)的溶剂脱沥青过程进行了深入的研究。首先对劣质减渣在乙酸乙酯溶剂和C4溶剂中的溶解度进行了测定。实验结果表明：温度对劣质减渣在两种溶剂中溶解度有显著的不同影响。随着温度的升高,劣质减渣在乙酸乙酯中的溶解度呈线性增加,而在混合C4溶剂中则呈线性降低。此外,改变溶剂组成或者改变劣质减渣溶解度参数,将有利于提高对劣质减渣的溶解能力。在本实验条件下,劣质减渣在混合C4溶剂中的溶解平衡模型遵循Flory-Huggins方程。其次,对劣质减渣掺炼CT后体系性质作了考察。通过原料的基本性质分析以及模拟蒸馏实验,考察VR和CT的相容性。当CT的添加量等于5%时,体系中溶解和吸附过程达平衡；当CT的浓度增加,体系中吸附过程起主要作用,沥青质易沉降析出。VR掺炼CT后的实沸点蒸馏以及延迟焦化等实验表明,掺炼CT能够对VR的加工过程有一定积极影响,但是也会造成液体油收率低,装置易结焦、运行周期短等问题。在上述基础上,以乙酸乙酯为溶剂考察了掺炼高温煤焦油对劣质减渣溶剂脱沥青过程的影响,并与掺炼粉煤的过程进行对比。实验表明：掺炼CT对劣质减渣的SDA过程有一定的改善。在萃取温度30℃、溶剂比6：1的优化条件下,掺炼10%CT时,DAO收率比纯渣油提高2个百分点,残炭脱除率基本不变,金属镍与钒总含量下降5μg/g,含硫量略有下降,含氮量基本不变。相同收率的DAO性质比较,VR掺炼10%CT后获得的DAO的金属、硫、残炭等含量明显下降。同时,DOA性质表明掺炼CT有利于劣质渣油深拔。劣质减渣掺炼30%北宿烟煤粉煤(150～830μm)预处理(250℃)后的SDA实验中,DAO收率提高近3个百分点,金属Ni和V脱除率分别提高了7个百分点和10个百分点。但此工艺存在原料输送困难、设备磨损严重、装置需改造等缺点。以C4烃类为溶剂,考察亚临界状态下劣质减渣掺炼CT的SDA过程。实验表明：在相同萃取条件下,与未掺炼时相比,掺炼10%CT,DAO收率提高17个百分点。掺炼20%CT,则提高近19个百分点,DAO的镍钒含量从3.41μg·g-1下降到2.69μg·g-1,沥青质含量从1.6 wt%减少到0.7 wt%。金属脱除率基本未下降。另外对相同收率的DAO性质进行了比较：高温煤焦油掺炼量<20wt%时,DAO的金属脱除率、硫氮脱除率明显提高,残炭脱除率基本不变。利用红外光谱、核磁光谱、紫外光谱、凝胶色谱等手段表征DAO分子结构信息,得出劣质渣油掺炼CT后,其轻组分更易被萃取到DAO中,DAO含更多的直链烷烃、侧链烷烃。采用固定流化催化裂化床对DAO的催化裂化性能进行了评价,结果表明：掺炼10%CT后获得的DAO同样具有良好裂化性能,轻质油收率提高近6个百分点,汽、柴油馏分性质和未掺炼CT时接近。同样,中东混合劣质减渣的SDA实验表明,掺炼10%CT比纯渣油能多深拔4个百分点的具有相近裂化性能的符合重油催化裂化原料要求的DAO。同时,脱油沥青(DOA)可制作气化原料。这进一步表明劣质减渣掺炼CT通过SDA-FCC组合工艺进行轻质化更获得更多的轻质油。最后原料的流变性能、胶体结构、溶解度参数研究结果揭示了劣质减渣掺炼高温煤焦油改善SDA效果的机理。劣质减渣掺炼CT,能够改变劣质渣油胶体体系的组成和相容性,使其粘度降低,胶体稳定性下降,溶解度参数减小。提高溶剂脱沥青过程的传质效率,使更多的可溶组分被抽提出来,提高DAO收率和改善质量。更多还原

【Abstract】 It is the main route to increase fuel-efficient and economic benefit by improving light oil and industrial chemicals yields of inferior oil. The solvent deasphalting (SDA) process is an important methods to obtain light oil from heavy oil. However, the industrial operation is in a dilemma:the yield is low when the quality of deasphalting oil (DAO) can satisfy the feedstock catalytic cracking (FCC) standard; to increase the yield, the quality is impaired, thus, can not attain the FCC feedstock standard. In order to gain more DAO from vacuum residue (VR). Asphaltene, heavy metal and part of the sulfur and nitrogen compound in the product should be removed and ensure its quality is satisfied with the requirement of the secondary operation by the current SDA equipment and technical, there is an interesting prospect to develop coprocessing technology of oil-coal. The importance is prominent especially today when the oil price is continuing high and the pressure of environment protection keeping growing. Moreover, China is lack of oil, short of gas, but rich of coal.Firstly, VR SDA process blend with high temperature coal tar (CT) was investigated in this paper. The solubility of the VR in ethyl acetate and C4 sovent had been tested separately firstly. It shows the solubility of VR in the two solvents is sharply affected by temperature. The solubility increases linear with growth of temperature in ethyl acetate, while decreases in C4. In addition, the VR solubility can be affected by components of the C4 and the solubility paramater. The solubility equilibrium model of VR in mixed C4 is followed Flory-Huggins equation.Secondly, the property change of VR-CT blend had been investigated. By analyzing the property of the raw material and simulated distillation experiment, the compatibility of VR and CT was studied. There is equilibrium between solution and adsorption when the CT blend ratio is 5%. When the ratio increases, the main effort in the system is adsorption and the asphaltene is easy to subside and separate out. It has been revealed by the TBP distillation and delay coking experiments that, though there is positive effect on the VR product process by blending with CT, the liquid oil yield has been decreased, the equipment are easy to coking and short the operation cycle.Based on the results above, the effect on VR SDA process by blending with CT had been researched and compared with the process that blending with powdered coal, with ethyl acetate as solvent. The result shows that there is some improvement on the VR SDA process by blending with CT. In the optimized condition of extraction temperature 30℃and solvent ratio 6:1, the DAO yield has been increased by 2% when blended with 10% CT. Meanwhile, the removal rate of carbon residue kept unchanged, the total content of nickel and vanadium has a decrease of 5μg/g, with the sulfur content has a slight decrease and the nitrogen content stays invariable. With the same DAO yield, the contents of metal, sulfur and carbon residue in DAO obtained from VR that blended with 10% CT decreased obviously. And the property of DOA revealed that blending with CT is benefit for the deep cut of the VR. In the SDA process that VR is blended with 30% Beisu bituminous coal powdered coal (150～830μm) and pretreated in 250℃, the DAO yield has been enhanced by 3%. the removal rate of metal nickel and vanadium has increased by 7%. This technical process, however, has many disadvantages, such as, with difference to transpot the feedstock, the damage to the equipment, and need to reform the device.The SDA process of VR blending with CT was investigated in subcritical state with C4 hydrocarbon as solvent. Compared with VR without any blend, the DAO yield has been improved by 17% with a CT blend ratio of 10% under the same extract condition. The improvement is around 19% when the blend ratio is 20%. The nickel and vanadium content is declined from 3.41μg·g-1 to 2.69μg·g-1, and the asphaltene content is declined from 1.6 wt% to 0.7 wt%. But the metal removal rate is nearly the same. The property of the DAO with the same yield has been compared. When the CT blend ratio is low (<20 wt%), its removal rate of metal, sulfur and nitrogen has increased distinct, while the carbon residue removal rate remain unchangeable. The DAO molecular structure has been studied by various methods: infrared spectrum, nuclear magnetic resonance, ultraviolet spectrum, gel chromatograph, and mass spectra. The results exhibit a more straight-chain and side-chain paraffin content in the DAO, for the light component is easier to be extracted into it by blend with CT.The catalytic cracking property of the DAO was evaluated by fixed fluid catalytic cracking bed. DAO obtained from VR that blended with 10% CT showes a fine cracking property. The light oil yield has been promoted by 6%. And the properties of the gasoline and diesel fraction are close to that without any blend. Results of SDA process on Middle East mixed inferior VR reveales that when blend with 10% CT, the DAO yield is improved by 4% and property of the DAO is similar and coincide with the heavy oil catalytic cracking raw material standard for DAO. Meanwhile, the deoiled asphalt (DOA) can be used as feedstock for gasifying. These results reveales further that, by blending with CT, more light oil can be gained from inferior VR in the SDA-FCC combination process.The effect mechanism of SDA process when VR was blended with CT had been investigated, and it was exposited by the research results of rheological behavior, colloid structure and solubility parameter of raw material. Component and compatibility of the VR colloid system was altered when blend VR with CT. Its viscosity declined, the stability of the colloid got worse, and the solubility parameter decreased. The mass transfer efficiency of the solvent deasphalting process was improved. More components have been extracted into DAO. The yield and quality of DAO have both been promoted.更多还原