【作者】 石振东；

【导师】 翟玉春；

【作者基本信息】 东北大学 ， 冶金物理化学， 2009， 博士

【摘要】 含硫原油中的活性硫对炼油、储运等设备有腐蚀作用,生成硫铁化物的自燃性给生产带来安全隐患。硫铁化物的自燃性受锈蚀前体的组成和硫化深度、相对湿度、硫化温度和气氛等因素的影响。本文以Fe2O3、Fe3O4、Fe(OH)3和单质硫为模型化合物,研究含硫油品对设备高温腐蚀产物的自燃性及自燃预防措施。在不同条件下进行铁氧化物的高温硫化和氧化实验,采用XRD、DTA-TG、低温N2吸附-脱附和化学分析等技术表征含铁物种的物相、组成和热效应的变化,研究高温硫化产物自燃倾向与诱发因素的关系,弄清影响铁氧化物高温硫化和硫化产物自燃性的关键因素。对微波辐射油品氧化脱硫技术、开发复合硫铁化合物清洗剂等预防措施进行实验研究。XRD和化学定量分析结果表明,硫对设备内表面腐蚀产物的组成和物相极其复杂,其中Fe2O3、Fe3O4和FeO(OH)是铁锈的主要成份,按质量分数计：Fe2O3约为62.0%,Fe3O4约为27.2%,Fe(OH)3约为10.8%。低温N2吸附-脱附和硫化实验结果表明Fe2O3、Fe3O4和Fe(OH)3三种试样的比表面积由大到小的顺序为Fe(OH)3＞＞Fe2O3>Fe3O4。单质硫与Fe2O3、Fe3O4和Fe(OH)3的高温硫化腐蚀产物主要是FeS2,并有少量其他类型的硫铁化合物,如FeS、Fe1-xS、Fe2(SO4)3、Fe(OH)SO4和FeSO4,其种类和数量与硫化温度有关。对比单质硫的差热-热重曲线和单质硫与Fe2O3、Fe3O4和Fe(OH)3样品反应的差热-热重曲线,得出单质硫与Fe2O3反应的初始温度是233.34℃；与Fe304反应的初始温度是308.47℃；与Fe(OH)3反应的初始温度是287.67℃。单质硫与Fe2O3和Fe(OH)3硫化产物中FeS2质量百分含量都随硫化温度升高、硫化时间延长而增大；单质硫与Fe3O4硫化产物中FeS2质量百分含量也随硫化温度升高而增大。高温硫化产物的自燃性与硫化物前体种类关系密切。Fe3O4高温硫化产物氧化自燃性很低,Fe2O3和Fe(OH)3高温硫化产物均有很高的氧化自燃性,并且与硫化温度和硫化时间、氧化温度、水含量和空气流速等因素有关。硫化温度越高,硫化时间越长,硫化产物的矿物化程度越高,由此导致产物硫化深度和结晶性均有所提高,在氧化过程中表现为硫化产物外层自燃性强而体相氧化速率较小。氧化温度越高、空气流率越大,硫化产物氧化反应速率越大,燃烧热效应越显著。当环境温度高于95℃时,单质硫与Fe2O3和Fe(OH)3的硫化产物自燃性较大；水分的存在能显著增大高温硫化腐蚀产物的自燃性。Fe(OH)3、Fe2O3和Fe3O4与单质硫高温硫腐蚀产物的氧化自燃性从大到小依次为Fe(OH)3、Fe2O3、Fe3O4。研究表明,采用微波辐射-过氧化氢/乙酸氧化脱硫法,在微波辐射压力0.5MPa、恒压辐射时间5min、辐射功率350W、复合溶剂用量为理论用量的13倍、氧化剂油比0.25:1、DMF萃取剂油比1:1、静置时间10min的条件下,可使辽河常二线柴油脱硫率达到89.6%,硫含量降至500μg·g-1以下,达到欧洲Ⅱ类标准,符合我国轻柴油质量标准。研制出新型复合硫铁化合物清洗剂。该清洗剂对硫铁化合物清除率和清除速率均高于国内同类产品,成本低、自身腐蚀性小且更加环境友好。本清洗剂已在炼厂的设备清洗过程中得到示范论证和工业应用,并取得了良好的效果。此项研究为炼油企业安全生产提供了有关硫铁化合物氧化放热自燃的较详细资料,同时根据实验研究结果提出了有效的预防措施,为炼油设备和装置的安全运行提供了科学依据,有效抑制和消除了因硫铁化合物氧化自燃而引发的火灾和爆炸事故,对石化企业安全生产具有一定的指导意义。更多还原

【Abstract】 Active sulfuric species derived from crude oil can react with rust formed on storage tanks, vessels and tankers to form various iron sulfides, and the tendency for these compounds to spontaneously react with oxygen in air may bring a potential trouble for oil processing and storage. Pyrophoric nature of the iron sulfides, exposed to moist air, is confirmed relevant with composition and sulfurized degree of rust and also with ambient temperature and relative humidity. The present subject target is supposed to clarify the effect of pivotal factors on both the sulfurization of iron oxides and the spontaneous oxidation of the iron sulfides, especially to explore the water induction for pyrophoric mechanism of the iron sulfides. In present work, we conduct the new topic, namely researching on combustion tendency of high temperature corrosion products and preventive measures for storage tanks of containing sulfur oil. Iron oxide sulfurization and ferric sulfide controllable oxidation will be performed under various reaction conditions, and characterized by XRD、DTA-TG、N2 adsorption-desorption and chemical analysis in order to determine phase composition, ferric valence state and reaction enthalpies. The oil desulfurization technology was demonstrated by microwave radiation, and the study on new cleaning agent for removing the composite of iron sulfides was investigated simultaneously.The results obtained by powder X-ray diffraction and quantitative chemical analysis point out that the rust was formed with very complicated composition and phases, consisting of mainly Fe2O3, Fe3O4 and FeO(OH) as the compositions of 60.2%,27.2% and 10.8%. The low temperature N2 adsorption-desorption showed that the specific surface areas decreased orderly as Fe(OH)3＞＞Fe2O3> Fe3O4. When element sulfur reacted with Fe(OH)3, Fe2O3 and Fe3O4 under the condition of high temperature, FeS2 was mainly formed, along with the generations of other compounds in very low contents, such as FeS、Fe1-xS、Fe2(SO4)3、Fe(OH)SO4 and FeSO4, which were formed to depend on the reaction temperatures. Upon these DTA-TG curves for element sulfur only and the products of element sulfur reacting with Fe2O3、Fe3O4 and Fe(OH)3, the starting reaction temperatures of Fe2O3, Fe3O4 and Fe(OH)3 with element sulfur is 233.34℃,308.47℃and 287.67℃, respectively. And the FeS2 contents in the sulfidation products of Fe3O4 and Fe(OH)3 were observed to increase with both sulfidation temperature and sulfidation time.For high temperature sulfurization products the pyrophoric nature depended obviously on the precursor species of sulfides. Compared with the case of Fe3O4 as the precursor, the high temperature sulfurization products concerning Fe2O3 and Fe(OH)3 as precursors showed a remarkable pyrophoric tendency, which were affected obviously by the factors of sulfurization temperature, sulfurization time, sample moisture as well as air flow rate. Iron oxide red and iron hydroxide were sulfurized with element sulfur to form mineralized sulfides under reaction conditions of high temperature and long time, while the formed sulfides were confirmed with high crystallinity and deep sulfurization. In this case, the sulfide shell, other than the bulk phase, showed both the obvious pyrophoric nature and the high oxidization rate. Usually the sulfides were oxidized rapidly along wtith remarkable combustion enthalpies as increasing reaction temperature and air flow rate. The sulfides of element sulfur reaction with Fe2O3 and Fe(OH)3 showed higher pyrophoric tendencies when ambient temperature was higher than 95℃. The existence of water remarkably increases the pyrophoric oxidation of sulfidation products. The pyrophoric tendency of high temperature products sulfided by using element sulfur decreased as the order:Fe(OH)3> Fe2O3> Fe3O4.The results indicated that, by using microwave radiation in the presence of hydrogen peroxide-acetic acid composites, desulfurization level arrived at 89.6% and the sulfur content at least down to 500μg·g-1 for Liaohe atmospheric two-stage distillation diesel oil under the conditions as following:0.5 Mpa of microwave pressure,5 min of constant pressure radiation time, composite dosage being 13 times of theory value,0.25 of ratio of H2O2 to oil,1.0 of ratio of DME extraction reagent to oil,10 min of static depositing time. The technology mentioned above could update Liaohe atmospheric two-line distillation diesel oil to meet the Europe StandardⅡand the China Standard for light diesel oil.A new composite desulfurization reagent was developed with the nature of low cost and light corrosion. It was demonstrated in refine with both high desulfurization level and high desulfurization rate compared with the domestic commercial products employed now.The detailed data concerning pyrophoric nature of iron sulfides were offered in present work, and effective prevention measures were given according to the researching results. The prevention measures were proposed to restrain and even avoid the occurrence of a fire as well as an explosion due to pyrophoric oxidation of iron sulfides in refineries. And it was of great constructive value to safe operation of all petroleum chemical companies.更多还原