Study on the Effect of Water on the Formation and Pyrophoricity of Ferrous Sulfide

Abstract

Rust formed by corrosion on the inner surfaces of oil tanks can react with humidity-saturated hydrogen sulfide. The reactions produce pyrophoric ferrous sulfide and can cause fire and explosions when exposed to air during production or maintenance. Water content has an important effect on both the formation and the pyrophoricity of ferrous sulfide and the effect was investigated in detail in this article. The experimental results showed that water is involved in oxidation reaction of ferrous sulfide and enhances the pyrophoricity, making ferrous sulfide more dangerous and able to easily cause fire or explosion accidents.     

Bacterial Mining

Abstract

Bacterial mining (biomining) represents the use of microorganisms to leach out metals from ores or mine tailings (wastes), followed by the subsequent recovery of metals of interest from the leaching solution. This leaching of metals from ores is a natural process, which can be considerably accelerated by inducing and/or supporting the microbial activity of certain species with the ability to solubilize metals. This process is usually known as biosolubilization and constitutes the basis of many remedial technologies for environments polluted with metals, and also providing the additional potential for recovery of any particular metal of interest. Bacterial mining is part of a vast research field that emerged relatively recently as a border science called biohydrometallurgy. This research field became very important in the context of raw material crises on which technological crises is grafted. In other words, the conventional technologies operating for metal extraction, mainly in the case of lower grade ores, are generally disruptive and less cost-efficient when compared to biomining. Thus, during the last 10–15 years, the interest in biohydrometallurgy, and subsequently in bacterial mining, has increased. The focus has been on two main topics—mineral bioprocessing and biorecovery.     

Corrosion in Propane Deasphalting Unit in a Lube Producing Refinery: A Case Study

Abstract

Propane deasphalting is a process of recovery of hydrocarbon distillates from vacuum residue by extracting with liquid propane. A plated tower is used to carry out extraction where extract containing the deasphalted oil and raffinate containing the asphalt are separated. Extract and raffinates are then subject to propane recovery sections wherefrom propane is recovered and reused in extraction. Complete recovery of propane from deasphalted oil is carried out by flashing alone, but recovery from asphalt requires heating in a furnace followed by flashing. Severe corrosion has been observed in the propane condensers, coolers, and the overhead lines of the flashers and stripper columns. Studies have indicated that cracking of asphalt at the prevailing operating temperature and pressure, generating hydrogen sulfide, was the sole reason for corrosion. The problem has been minimized by adjusting the temperature and pressure without affecting the propane recovery efficiency.     

An assessment of electrolytic hydrogen production from H2S in Black Sea waters

In the deeper parts of the Black Sea basin, water is anoxic. Hydrogen sulfide (H₂S) occurs naturally, and its concentration is nearly constant, around 9.5 mg/L at 1500 m depth. Its high solubility, and the existing chemical environment facilitate its accumulation and containment in the seawater, and its extraction poses a challenge.Possibility of hydrogen and sulfur production from H₂S contained in the waters of Black Sea is investigated conceptually. A multistage process is considered which involves extraction of seawater, adsorption of H₂S, electrochemical production of hydrogen and polysulfides; fresh water production by desalination of seawater and further hydrogen production from the resulting salty solution through chlorine-alkaline electrolysis. Some consideration is included regarding the economic and environmental aspects of the process.     

Technical and Economical Analysis of Hydrogen Sulfide Removal from the Recycled Hydrogen in a Diesel Hydrodesulfurization Plant

Hydrodesulfurization (HDS) is a catalytic process used to remove sulfur compounds, which leads to very low sulfur concentrations. HDS turns more complicated and severe according to the feedstock boiling range, since sulfur compounds present in light cuts, normally sulfides and mercaptanes, are easy to remove, and sulfoaromatic compounds, specially polycyclics, are the more refractive ones (Speight, J. G. (1981). The Desulfurization of Heavy Oils and Residua. 2nd ed. Marcel Dekker, Inc.: Chemical Industries 4.) The hydrogen sulfide (H₂S) produced in the HDS has an inhibiting effect on the same reaction, as it has been widely observed (McCulloch, D. C. (1983). Applied Ind Catal. I:69; National Petroleum Refining Association (NPRA). (1993). Questions & Answers, 99; Leglise, J., Van Gestel, J., Duchet, J. C. (1994). Symposium on Advances in Hydrotreating Catalysts Presented before the Division of Petroleum Chemistry Inc. In: 208th National Meeting American Chemical Society. Washington D.C. p. 533). This effect is well known even at relatively low H₂S concentrations (2 mol%) for commercial operation conditions (Leglise, J., Van Gestel, J., Duchet, J. C. (1994). Symposium on Advances in Hydrotreating Catalysts Presented before the Division of Petroleum Chemistry Inc. In: 208th National Meeting American Chemical Society. Washington D.C. p. 533). Due to this, the H₂S removal from the recycled hydrogen to the reactor is mandatory in order to increase the desulfurization levels or to increase the processing capacity of an HDS plant. There are many options to low the H₂S concentration in the H₂ loop (Cooper, A., Stanislaus, A., Hannerup, P. N. (June 1993). Hyd Process 84; Johnson, A. D. (1983). Oil and Gas J 10:78; Nash, R. M. (1989). Oil and Gas J 13:47; Suchanek, A. J., Dave, D., Gupta, A., Van Stralen, H., Karlsson, K. (1993). In: NPRA Annual Meeting AM-93-24; Tippett, T., Knudsen, K. G. (1999). In: NPRA Annual Meeting. San Antonio, TX. 1999 NPRA Annual Meeting, San Antonio, TX, AM-99-06.), which are from a simple purge adjustment for light naphtha HDS to a full treatment of the H₂ stream for middle distillate HDS, where the H₂S concentration can reach levels of 10 mol% (National Petroleum Refining Association (NPRA). (1993). Questions & Answers, 99). This work presents the economical analysis of the introduction of an Amine Treating Unit in an HDS plant in operation to remove H₂S from the H₂ stream recycled to the reactor.     

安塞油田硫化氢成因研究

硫化氢是石油伴生气中的有害成分之一。目前有关油气田伴生硫化氢的成因,存在着生物成因(SBR)、热化学成因(TSR)两种不同观点。本文从安塞油田地质环境条件下的烃类与岩心中的金属硫酸盐反应热力学分析,探讨了石油生产过程中硫化氢产生的可能机理,并结合地层水质分析及岩心分析结果,发现在安塞油田地质条件下,井下缺少微生物活动的必要条件,从而排除了BSR成因的可能性,论证了TSR成因应为安塞油田硫化氢产生的主要原因。     

EF—2型特种氧化铁常温精脱硫剂的研制

采用浸渍法制备了ＥＦ—２型特种氧化铁常温精脱硫剂,研究结果表明,它有突出的精脱硫化氢性能,在进口Ｈ２Ｓ含量为１％时,出口Ｈ２Ｓ脱除精度＜００３×１０－６。在空速１０００ｈ－１时,精脱Ｈ２Ｓ的穿透（工作）硫容（出口Ｈ２Ｓ＜００３×１０－６）有Ｏ２时可达２０％～３０％,无Ｏ２或高ＣＯ２时为１０％～１２％。在１０～１２０℃之间评价,穿透硫容变化很小。提高空速,增加ＣＯ２的含量可使穿透硫容下降。增加Ｏ２含量或Ｈ２Ｓ含量有利于脱硫反应和穿透硫容的增大。穿透硫容随再生次数的增多而成倍递减。抗压碎强度和耐水性能优良,水煮２ｈ或浸泡一年均不粉化,在１２ＭＰａ１００多次急剧充压卸压强化试验后颗粒完整,抗压碎强度保持不变     

2,2'-硫代双对特辛基苯酚的合成研究

以对特辛基苯酚为主要原料,与新制备的二氯化硫在四氯化碳溶剂中反应,合成了２,２’－硫代双对特辛基苯酚（简称硫代双酚）。确定了反应最佳工艺条件：反应温度 ６～８℃,反应时间 ２ ｈ,对特辛基苯酚与二氯化硫摩尔比（简称酚硫比）２．０：１,溶剂与对特辛基苯酚的重量比（简称剂酚比）３．２：１,石油醚（３０～６０℃）中重结晶,得到硫代双酚收率达８７％以上。     

湿硫化氢环境压力容器开裂及无损检测技术

从湿硫化氢环境压力容器开裂分类及特点入手,分析研究了目前常用先进的无损检测技术的特点及适用性,筛选出对湿硫化氢环境压力容器开裂检测的最佳方法：全自动超声检测技术与实验室金相切片相结合