CAS OpenIR
油页岩非常规条件热解研究
Alternative TitleOil shale pyrolysis under non-conventional conditions
SOMPRASONG SIRAMARD
Thesis Advisor许光文
2017-05
Degree Grantor中国科学院大学
Degree Name博士
Degree Discipline化学工程
Keyword油页岩热解,内构件,减压,二次热解,快速加热
Abstract

基于当代巨大的能源消费量,油页岩作为一种可替代能源变得颇有前景。热解技术目前是利用油页岩生产高附加值产品的主流技术,其产物有页岩油及气体产品。热解过程的复杂化学反应,尤其是生成的热解油气的二次热解反应,极大地影响热解产物质量以及收率。本论文对油页岩热解挥发分释放过程所涉及反应展开深入研究,并归纳整理影响二次热解反应程度的主要因素。为了解不同的操作条件对油页岩热解二次反应的影响,首先考察其在小型固定床中热解反应特性。研究发现,颗粒床层厚度极大地影响页岩油收率,然而降低反应体系压力能够明显抑制该效果。在550 ℃条件下,随着颗粒床层厚度由20 mm 增加到150 mm,页岩油收率由10.28 wt.% 减少至9.72 wt.%。油品模拟蒸馏分析表明,床层厚度增加将导致页岩油中轻馏分油相对含量增加。此外,GC/MS分析结果显示油品中烷烃相对含量随床层厚度增加而减少,芳烃则相反。实验发现,在所有测试的床层厚度下,减少反应体系压力都能显著增加页岩油收率。在减压条件下,随着床层厚度增加,页岩油收率仅由10.75 wt.%略微减少至10.44 wt.%。但是,即使在最大床层厚度下,减压热解油收率也要明显高于常压热解收率。该研究结果表明减压对油页岩热解二次反应作用要强于床层厚度。进一步,在1-kg级固定床反应器中,考察减压下油页岩热解特性。该固定床反应器,加装了特制内构件,即中心集气管和传热板,相比于传统固定床反应器,有更好的热解反应性能。因此,基于该新型内构件反应器,通过降低反应体系压力进一步拓展并优化操作条件,以便得到更高品质页岩油产品。无论是在内构件反应器还是传统反应器,减少反应体系压力能够显著提高页岩油收率。但是,在内构件反应器中这种油品收率的促进作用更为明显。减压热解条件下,页岩油中重馏分含量更多,脂肪族化合物含量更高,芳香族化合物收率更低,该结果显著表明减压对二次反应的抑制作用。此外,在1000 ℃炉温,-40 kPa压力条件下,内构件反应器的油收率可达到Fischer Assay收率的97.57%(8.24 wt.% dry basis)。该研究结构表明,存在内构件和减压操作对页岩油收率和品质显著提高的协同作用。考察了红外加热快速升温固定床反应器中油页岩的热解特性。为最小化二次反应,采用自主设计的浅层红外加热固定床反应器,考察不同加热速率和热解温度下20 g规格油页岩热解。在最优的操作条件,即0.5 ℃/s 升温速率,550 ℃热解终温和-40 kPa压力下,得到最大的页岩油收率为11.10 wt.% (几乎达到Fischer Assay收率)。进一步提高加热速率,导致页岩油收率减少但气体产物收率增加。此外,提高加热速率有助于增加挥发分中的氢元素含量。25 ℃/s下的快速热解使得总挥发份的收率高于Fischer Assay的结果, 但页岩油收率低于Fischer Assay收率。快速热解过程中回收的页岩油中轻馏分含量更高,该结果表明利用本研究的红外加热实施的快速热解过程存在二次裂解反应。此外,研究还发现,多颗粒层热解相比于单颗粒层热解,二次反应程度更严重。这些结论表明:在所采用的红外加热反应器中,采用单颗粒层以及较低的加热速率和操作压力能够有效地抑制二次反应发生。通过实验研究,更深层次的认知了热解挥发分的系列反应。在本研究使用的快速加热条件下,固定床中生成的一次挥发分也不可避免地发生了二次反应。在本论文中所有测试条件下,减少反应压力都能够有效地抑制二次反应。总之,该论文表明单颗粒床层,低加热速率以及减压操作能够明显抑制二次反应,使得挥发分产物的损失减少,最终得到更高页岩油收率。;The utilization of oil shale as one of the alternative energy resources has become attractive nowadays due to the high-energy consumption. Pyrolysis is the main technology to utilize oil shale for generating high-value products in the form of shale oil and gas. The complex reactions in pyrolysis especially the secondary pyrolysis reactions of the generated vapors extremely influence the quality and quantity of pyrolysis products. This thesis intends to gain deep insights into the volatile release reactions to clarify the dominance of the retorting factors on the extent of the secondary pyrolysis reactions. The characteristic of pyrolysis in a small fixed bed reactor was firstly investigated under different operating conditions to evaluate their influences on secondary reactions. Particle bed thickness caused a significant effect to lower the shale oil yield, whereas reducing the reaction pressure evidently suppressed that effect. The shale oil yield decreased from 10.28 wt.% to 9.72 wt.% with increasing the particle thickness from 20 to 150 mm at a temperature of 550 ?C. The produced shale oil was lighter for the pyrolysis with higher bed depth. Moreover, for a thicker particle bed there was a lower content of aliphatic hydrocarbons but an increase in the content of aromatic species. The loss of shale oil yield through the influence of particle bed thickness was more severe at higher pyrolysis temperatures. Reducing pyrolysis pressure evidently increased the shale oil yield under all tested particle bed depths. The shale oil yield slightly decreased from 10.75 wt.% to 10.44 wt.% with the thicker particle bed under reduced pressure. However, this shale oil yield was evidently higher, even at the thickest bed depth, in comparison with that from the pyrolysis under atmospheric pressure. This verified that the vacuum pyrolysis effectively suppressed the secondary reactions caused by particle bed thickness.The pyrolysis of oil shale under reduced pressures was further investigated in one-kg fixed bed reactor. The pyrolysis in the fixed bed reactor mounted with the particularly designed internals, a central gas collecting pipe and a few heat transfer plates, has shown an obvious improvement on pyrolysis performance in comparison with that in the fixed bed reactor without any internals. Thus, this thesis further worked to optimize the operating conditions through reducing the reaction pressure in this newly devised fixed bed reactor to get better pyrolysis performance in terms of shale oil production. Reducing the reaction pressure evidently increased the shale oil yield for the reactor with and without internals. Nevertheless, the effect from lowering operating pressure was more obvious in the reactor with internals than in the reactor without internals. The produced shale oil by vacuum pyrolysis was heavier and richer in aliphatic compounds but having smaller aromatic species yields, obviously indicating the suppression of secondary reactions. Moreover, the oil yield under reduced pressure condition (-40 kPa) in the reactor with internals reached 97.57% of the Fischer Assay yield (8.24 wt.% dry basis) at a furnace heating temperature of 1000 ?C. Hence, there is certain synergistic effect between internals and reducing pressure to enhance the yield and quality of shale oil. The pyrolysis of oil shale was further carried out in an infrared heating fixed bed reactor. A newly shallow infrared heating fixed bed reactor was designed to investigate the characteristics of massive oil shale pyrolysis (20 g) at different heating rates and reaction temperatures under minimized secondary reactions towards the generated volatile. The maximum shale oil yield of 11.10 wt.% (almost 100% of the Fischer Assay yield) was obtained at the optimized operating conditions of a heating rate of 0.5 ?C/s and a pyrolysis temperature of 550 oC under a reduced pressure (-40 kPa). Further increasing heating rate decreased the shale oil recovery but got higher production of pyrolysis gas. Nevertheless, increasing heating rate increased the total proportion of hydrogen in the volatile products at a specified temperature. The rapid pyrolysis of oil shale at a heating rate of 25 ?C/s allowed higher production of total volatile in comparison with the Fischer Assay method. The recovered shale oil had more light oil components for the fast heating pyrolysis. The results indicate the existence of secondary cracking reactions with the tested rapid oil shale pyrolysis. Moreover, it has been found that pyrolysis of multilayer oil shale particles caused more serious secondary reactions than pyrolyzing oil shale in a single-layer. Therefore, the single-layer pyrolysis at a low heating rate and lowered operating pressure evidently suppressed the secondary reactions in this adopted infrared reactor. Through these studies, deeper understanding of the reactions for pyrolysis volatile of oil shale was obtained. There were inevitable secondary reactions to the released primary volatile even for the tested quick heating pyrolysis in the infrared heating reactor. Reducing reaction pressure effectively suppressed the secondary reactions for all tested conditions. Consequently, this thesis demonstrated that the pyrolysis of oil shale at a thin particle bed, low heating rate and reduced operating pressure had evidently suppressed secondary reactions, which thus caused the higher shale oil production. 

Language中文
Document Type学位论文
Identifierhttp://ir.ipe.ac.cn/handle/122111/26956
Collection中国科学院过程工程研究所
Recommended Citation
GB/T 7714
SOMPRASONG SIRAMARD. 油页岩非常规条件热解研究[D]. 中国科学院大学,2017.
Files in This Item:
File Name/Size DocType Version Access License
油页岩非常规条件热解研究.pdf(5887KB)学位论文 限制开放CC BY-NC-SAApplication Full Text
Related Services
Recommend this item
Bookmark
Usage statistics
Export to Endnote
Google Scholar
Similar articles in Google Scholar
[SOMPRASONG SIRAMARD]'s Articles
Baidu academic
Similar articles in Baidu academic
[SOMPRASONG SIRAMARD]'s Articles
Bing Scholar
Similar articles in Bing Scholar
[SOMPRASONG SIRAMARD]'s Articles
Terms of Use
No data!
Social Bookmark/Share
All comments (0)
No comment.
 

Items in the repository are protected by copyright, with all rights reserved, unless otherwise indicated.