Conversion of petroleum coke into valuable products using oxy-cracking technique
Conversion of petroleum coke into valuable products using oxy-cracking technique
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DOI：
10.1016/j.fuel.2017.11.103
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发表时间：
2018-03-01
期刊：
影响因子：
7.4
通讯作者：
Ortega, Lante Carbognani
中科院分区：
文献类型：
--
作者：
Manasrah, Abdallah D.;Nassar, Nashaat N.;Ortega, Lante Carbognani
全球残余原料的产量已达到每年1.5亿公吨，预计今后还会增加，因为原油的性质越来越重。石油焦（petcoke），这些残留物之一，是一种富含固体的碳，通常在炼油厂的重油改质和减压渣油延迟焦化过程中产生。由于气化和燃烧等传统工艺在效率和环境友好性方面存在局限性，因此迫切需要找到一种替代技术来处理大量石油焦。在这项研究中，氧裂解技术，这是一个组合的裂解和氧化反应，进行作为一种替代方法的石油焦利用。该反应在帕尔反应器中进行，其中石油焦颗粒溶解在含水碱性介质中，并在温和的操作温度和压力下部分氧化。考察了温度、氧气压力、反应时间、原料粒度和混合比等因素对石油焦氧化裂解的影响，优化了石油焦氧化裂解产物的溶解性和选择性。结果表明，温度和停留时间是影响反应转化率和选择性的两个主要参数。这使我们能够提出一个基于自由基机理的反应途径来描述石油焦的动力学行为。反应动力学表明，石油焦的氧化经历了一个平行的连续反应，其中氧化分解发生在第一步产生不同的氧化中间体。采用FTIR、XPS、NMR等手段对石油焦进行了表征。氧裂解产物中含有羧基、羰基、酚基和磺酸基官能团。此外，元素分析表明，大多数金属残留在残渣中，这表明所提出的技术可以用于石油焦脱矿。
The global production of residual feedstock has reached 150 million metric tons per annum and is expected to increase in the future due to the progressively increasing heavier nature of the crudes. Petroleum coke (petcoke), one of these residues, is a solid-rich carbon typically produced during the upgrading of heavy oil and delay coking of vacuum residue in the refinery. Finding an alternative technique to treat this massive amount of petcoke is highly needed as the conventional processes like gasification and combustion have limitations in terms of efficiency and environmental friendliness. In this study, an oxy-cracking technique, which is a combination of cracking and oxidation reactions, is conducted as an alternative approach for petcoke utilization. The reaction is conducted in a Parr reactor where petcoke particles are solubilized in an aqueous alkaline medium and partially oxidized under mild operating temperature and pressure. Several operating conditions on petcoke oxy-cracking were investigated, such as temperature, oxygen pressure, reaction time, particle size and mixing rate to optimize the solubility and selectivity of oxy-cracked products. The results showed that the temperature and the residence time are the two major important parameters that affect the reaction conversion and selectivity. This enabled us to propose a reaction pathway based on the radical mechanism to describe the kinetic behavior of petcoke. Reaction kinetics indicated that petcoke oxidation undergoes a parallel-consecutive reaction in which an oxidative decomposition took place in the first step producing different oxidized intermediates. The oxy-cracked petcoke was characterized by FTIR, XPS and NMR analyses. The oxy-cracked products were found to contain carboxylic, carbonyl, phenolic, and sulfonic functions. Moreover, the elemental analysis showed that most of the metals remained in the residue, suggesting that the proposed technique could be employed for petcoke demineralization.