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Process environments of high carbon activity (a c > 1) and low oxygen partial pressures (p O2) are often encountered in the petrochemical industry. Under these conditions a type of corrosion known as metal dusting occurs. Previous work has identified a 20Fe–40Ni–10Mn–30Cr high temperature alloy as a potential metal dusting resistant material. Knowledge of the kinetics and mechanism of the oxidation of the alloy under low p O2 conditions would provide a better understanding of its corrosion resistant behavior and guide future alloy development. The present work examines the selective oxidation of Mn and Cr in the 20Fe–40Ni–10Mn–30Cr alloy under low p O2 conditions. The conditions for oxidation were selected by fixing the p O2 value such that only Mn and Cr would oxidize. These p O2 values are representative of the conditions that exist in metal dusting type environments. A comparison of the oxide film chemistry and morphology with those formed under metal dusting conditions will inform whether the high carbon activity is playing a role in protective oxide film formation. Low p O2 values are obtained by using a 90:10 CO:CO2 mixture at 1,000 K. Under these conditions an oxide film rapidly forms on the surface of the alloy. Analysis of the oxidized alloy by electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy reveals that the oxide consists of a continuous spinel with the approximate stoichiometry of MnCr2O4, as well as islands of MnO and fibrillar structures of MnCr2O4 stoichiometry. The parabolic rate constant for the growth of the spinel is determined from thermogravimetric analysis [k p = (3.72 ± 0.01) × 10−14 g2 cm−4 s−1], TEM analysis [k p = (6 ± 3) × 10−14 g2 cm−4 s−1] and cross-sectional SEM [k p = (3 ± 1) × 10−14 g2 cm−4 s−1].

Steam cracking is a petrochemical process that cleaves a broad range of hydrocarbon feed molecules into a variety of light olefinic products, including the highly desirable ethylene. Over the course of a cracking operation using a feed mixture of a saturated hydrocarbon and steam around 900–1000 °C in tubular alloy coils located in fired heaters, coke inevitably forms on the inside surfaces of the furnace tubes and must be burned off and/or spalled off periodically using steam or a steam–air mixture. Furnace tube materials are predominantly based on chromia-forming alloys; such alloys can degrade by carburization and oxide–carbide conversion in such a mixed carburizing–oxidizing environment. These hurdles have been largely overcome by using an alumina-forming material that provides superior corrosion and coking resistance. Cracking hydrocarbons at much higher temperatures results in high selectivity to acetylene, which can be converted into many petrochemical products including ethylene. The desired hydropyrolysis reaction from hydrocarbons to acetylene can be realized in a reverse-flow reactor operating above 1500 °C in a scaleable manner. The reactor elements include ceramic components that are placed in the hottest regions of the reactor, and must withstand temperatures in the range of 1500–2000 °C. Moreover, the materials in the hot zone are exposed alternately to a regeneration (heat addition) step that is mildly oxidizing and a pyrolysis (cracking) step that is strongly reducing with a correspondingly high carbon activity. This paper addresses the thermodynamic stability of selected ceramic materials based on alumina, zirconia, and yttria for such an application. Results from laboratory tests involving the exposure of these ceramic materials to simulated process conditions followed by their microstructural characterization are compared with expectations from thermodynamic predictions.

A reverse-flow reactor enables the pyrolysis of hydrocarbons at temperatures up to 2000 °C to high value petrochemical products. Materials in the reactor hot zone, exposed to such extreme temperatures, are also subject to rapid oxidative cycling over a period of several seconds between a regeneration (heat addition) step that is mildly oxidizing and a pyrolysis (cracking) step that is strongly carburizing. This paper addresses the performance of a class of zirconate ceramics such as BaZrO3, SrZrO3, and La2Zr2O7 that have been tested in a laboratory scale reverse-flow reactor and compares the results with thermodynamic predictions. It is observed that zirconate ceramics degrade by decomposition to zirconia and the second oxide, vaporization of the second oxide, and ceramic dusting corrosion of zirconia that involves carbide-oxide inter-conversion and carbon precipitation. The pyrolysis reaction promotes carbon deposition and carburization of zirconia leading to the formation of a non-protective porous carbide layer. The regeneration reaction converts the carbide layer partially back to oxide while also oxidizing away some of the deposited carbon. Repeated cycles of pyrolysis and regeneration steps eventually result in the breakup of the bulk zirconate ceramic structure into powder or dust.

Currently, the pyrolysis of hydrocarbons for the production of light olefins is almost exclusively carried out in steam crackers operating around 900–1000°C. However, cracking hydrocarbons at much higher temperature results in high selectivity to acetylene, which can be converted into many petrochemical products including ethylene. The desired hydropyrolysis reaction from hydrocarbons to acetylene can be realized in a reverse-flow reactor at very high temperatures (>1700°C) in a scalable manner. The reactor elements include ceramic components that are placed in the hottest regions of the reactor and must withstand a temperature that is in the range of 1500–2000°C. In addition, the temperature rises and falls with the reverse-flow cycle; a fluctuation that could be as high as 100–500°C over a period of several seconds. Moreover, the materials in the hot zone are exposed alternately to a regeneration (heat addition) step that is mildly oxidizing, and a pyrolysis (cracking) step that is strongly reducing with a correspondingly high carbon activity. This article addresses the thermodynamic stability of selected ceramic materials based on alumina, zirconia, and yttria for such an application. Results from laboratory tests involving the exposure of these ceramic materials to simulated process conditions followed by their microstructural characterization are compared with expectations from thermodynamic predictions.

Copper and Cu-based alloy coatings suppress carbon transfer to the metal surface from carbon-supersaturated gaseous environments. The metal dusting resistance of such coatings has been investigated in CO-H2 gas mixtures at temperatures ranging from 450°C to 700°C. Conventional plating and cladding methods have been employed to deposit Cu-based materials on the surfaces of commercial materials such as 2.25Cr-0.5Mo steel and carbon steel. In addition to the performance of Cu-based materials under laboratory conditions, the effect of alloying elements such as Sn, Zn, Ni and Al in Cu on the corrosion process and the coating/substrate interface stability are discussed with particular attention to commercial scale applications.

Metal dusting corrosion of NiCrAl(Y)-based alumina forming coatings has been simulated in carbon-supersaturated environments (CO-H2) at 650{degree sign}C. Atmospheric plasma spray (APS) and powder plasma welding (PPW) methods have been employed to deposit alumina forming coatings on Inconel 601 substrate alloy surfaces. Since most currently available high temperature alloys are prone to metal dusting, understanding and thereby controlling metal dusting corrosion is key to many operations and developments related to syngas production. The focus of this research is to evaluate the performance of alumina forming coatings under laboratory conditions. In addition to the effect of coating chemistry and microstructure (based on method of application) on the corrosion process, the mechanistic aspects of metal dusting are discussed with particular attention to the stages of microstructure evolution as degradation proceeds.

Reactor vessels and internals used for high-temperature processes such as in refining and chemical industries are exposed to aggressive fluids often containing hard catalyst particles moving at high velocities. The protection of these vessels and internals against erosion- and corrosion-induced material degradation is a technological challenge. The life span of the state–of-the-art monolithic refractory liners currently in use is limited by excessive mechanical attrition of the liner from high-velocity solid particle impingement, mechanical cracking, and spalling. The advanced TiB2-stainless-steel (SS) cermets are designed for chemical stability required for long-term service and offer an order of magnitude higher erosion resistance over the state-of-the-art, high fracture toughness (K1C∼12 MPa m1/2) and excellent corrosion resistance (kp∼1.9 × 10−11 g2/cm4/s at 800°C in air). Materials, design, microstructure, key mechanical properties, erosion, and corrosion resistance of the newly developed TiB2-SS cermets are presented.

Reverse-flow reactors achieve the desired hydropyrolysis reaction of natural gas and other hydrocarbon feeds at very high temperatures of up to 2000°C, which enables the production of many high-value chemicals. To identify refractory ceramic materials suitable for constructing key components of the reactor, the full range of solid solutions between zirconia and yttria having 18 to 100 mol% yttria have been tested in a laboratory reactor. Conventional yttria-stabilized zirconia (YSZ) materials having 8 mol% Y2O3 appear to accommodate reactor thermal severity, but are prone to a new form of corrosion termed ceramic dusting that is observed when pyrolysis and oxidation cycles are alternated under reverse-flow conditions. Yttria and high yttria–zirconia ceramics having ~80 mol% or more yttria suppress ceramic dusting corrosion in steam-free pyrolysis environments. The addition of low levels of steam of ~5% to the pyrolysis gas stream increases the stability of YSZ materials substantially, so that the stability threshold is closer to 40 mol% Y2O3 in the yttria–zirconia system. The two approaches can be combined to optimize reactor performance. Key experimental results are presented and discussed taking into account the thermodynamic phase stability of the different phases.

As analysed in the previous chapter “Intermediated Securities and Private International Law”, it is evident that there has been huge legal uncertainty as to which law governs cross-border transactions of intermediated securities under the lex rei cartae sitae rule, which is a traditional connecting factor of directly held securities certificates having carried out an adequate disclosure function in the direct holding system. This uncertainty causes a collateral taker to hesitate to make securities collateral transactions with a collateral provider, who holds securities through her intermediary, in the sense that from the perspective of the collateral taker, although it is an essential point to acquire valid security interests, which are enforceable against a third party, it is not easy to determine the law applicable to the collateral transaction under the lex rei cartae sitae or the lex situs rule. Even if this is possible, as mentioned, it is still a costly and time-consuming task, which results in complex practical and legal problems, thereby depreciating the value of securities as collateral. In addition, especially in the global financial market, where jurisdictions are closely inter-connected to, and inter-dependent on, each other, uncertainty in one jurisdiction can rapidly spread to another jurisdiction, exposing intermediaries and investors to systemic risk. In this regard, in May 2000, the Hague Conference on Private International Law (“HCCH”) proposed to develop an international instrument on intermediated securities, and disposition thereof, and adopted the final draft of the Hague Securities Convention on 13 December 2002 in the second part of the Nineteenth Diplomatic Session of the Hague Conference, after holding the Experts meeting in January 2001 and the Special Commission in 2002, and 17 regional discussion workshops.

Despite a long period of aspiration to establish a single integrated European financial market since 1966, when the Segre Report was published, the European Union (“EU”) has not fulfilled the goal of market integration yet. Thus, the EU post-trading sector, the main subject area of the intermediated system, is also still to a large extent fragmented, without a harmonised acquis communautaire for European intermediated systems. This does not mean, however, that there has been no effort or progress for reform with respect to the integrated European financial market, including the intermediated system. It can be said that the most influential initiatives for reform started with the Financial Services Action Plan (“FSAP”) and the Committee of Wise Men’s report (“Lamfalussy Report”), and that more specifically, inter alia, the Giovannini Group’s reports (“Giovannini Reports”) have rolled out a roadmap to tackle the problems of the European securities clearing and settlement regime. Based on these initiatives, European legislation and progress for market integration have been made. In relation to the intermediated system, the following Directives are worth noting: the Settlement Finality Directive in 1998, the Financial Collateral Directive in 2002, the Insolvency Regulation in 2000, the Winding-Up Directive in 2001, the Directive on Markets in Financial Instruments (“MiFID”) in 2004, and the Shareholders’ Rights Directive in 2007. Most recently, the Commission is preparing a Draft Directive on Legal Certainty of Securities Holding and Transactions (Securities Law Directive), which is scheduled to be concluded by the end of 2012.

While Swiss civil law has both Romanic and Germanic legal traditions, the law of securities belongs to the Germanic legal tradition. Under the strong influence of von Savigny’s materialisation theory, as in Germany, securities (Wertpapiere) are not mere shares or bonds, but share certificates and bond certificates embodying such equity, debt or other private rights with value. Unlike Germany, however, the Swiss Code of Obligations (“SCO”) expressly provides the definition of securities, similar to the German common view regarding securities, initially defined by Heinrich Brunners. Article 965 of SCO specifies that a securities certificate (Wertpapier) is any certificate with which a right is combined in such a way that without the certificate, the right may neither be exercised nor transferred to another. As in Germany, securities, i.e. rights incorporated in securities certificates, are transferred by delivering the possession of securities certificates (Arts. 967 & 969 of SCO). Meanwhile, although Swiss Civil Code (“SCC”) does not have a clause defining a thing (Sache), objects of ownership regarding movables (Fahrniseigentum) are tangible things and natural forces that may be subject to legal control (Art. 713 of SCC), and it is understood that corporeality (Korperlichkeit) is the central element in the definition of things. As in Germany, transfer of movables is required to deliver possession of the movables to the transferee (Art. 714 of SCC). As a result, Switzerland also employs a medium of papers to apply the rules of property law to securities and their transfers, treating the papers as tangible things.

As observed in the preceding section, current conflict of laws analysis varies, according to the lex fori and its analysis, which causes, in many cases, forum shopping. A worse problem is that in practice, without a clear and specific PIL rule for intermediated securities, and if the traditional lex situs rule is applicable, it is difficult or almost impossible from the perspective of a collateral taker to know, in advance, how to satisfy all the perfection requirements of the collateral securities which the collateral taker will receive. For instance, assume that Japanese Collateral Provider A holds, through her Intermediary X incorporated under Korean law, and located in Seoul, a portfolio of German bearer bonds in the form of a global securities certificate which is held, in turn, with a German bank located in Hamburg, and in custody in the vault of the German central securities depository, i.e. CBF. Further assume that she holds dematerialised Japanese shares, listed on a Korean exchange through the CSD linkage between KSD and JASDEC, and certificated debt securities, issued by a Quebec issuer, which are, in fact, in custody with the offices of CDS, the Canadian CSD in Ontario, Quebec, British Columbia and Alberta. She also holds American depositary receipts, issued by the Bank of New York held in the Belgian CSD, Euroclear, Belgium’s vault in Belgium. Let’s further assume that German Collateral Taker B tries to find legal advice before her (pledge) collateral transaction, which will be concluded in accordance with English law. In this context, it would be extremely difficult to deliver a proper advice, because, first of all, the advice might be different depending on a forum court as discussed above. Additionally, from a practical point of view, it is time-consuming and costly work to obtain all the information on, according to each type of security, where the securities certificates are actually located, and whether the securities are dematerialised or otherwise, as well as meeting all the legal requirements and acquiring other necessary legal information for the collateral transaction, even if securities types and their locations are detected. Since, in practice, unlike the above hypothesis, it is quite difficult to find the location, it is not difficult to be led to the conclusion that the traditional lex situs rule is an almost impracticable and inappropriate connecting factor in respect of intermediated securities.

Simply put, the current German intermediated system is a traditional legal regime in accordance with German property law; this is the most prominent feature of the German system. Due to this characteristic, however, a few theoretical, interpretative problems and disputes arise. In fact, domestically and internationally there are quite a few criticisms with respect to the current German intermediated system, stemming from unnatural applications of property law. Notwithstanding, the current system may be understandable from the viewpoints that German property law is fundamentally constructed on the basis of constructive legal notions, and that law might be defined as an aggregate of facts and fictions, except for consideration of its reasonableness and efficiency. The following discusses the basic structure and the main features of the German intermediated system.

The protection of an innocent acquirer plays a pivotal role in intermediated securities transactions, for despite massive and speedy securities transactions in the intermediated system, a purchaser of intermediated securities may have the legal certainty that her intermediated securities are not subject to any adverse claim, unless she had an actual or constructive notice of the fact that her acquisition could violate another’s interest. The innocent acquisition rule, thus, ensures settlement finality in the intermediated system, and facilitates dynamic safety of securities transactions. However, due to the special characteristics of intermediated securities transactions, such as book-entry transfers without physical securities deliveries, and anonymity of counterparties of transactions on a stock exchange in general, it was considered that the concept of the traditional so-called good faith acquisition or bona fide acquisition which is applied to a tangible property is not appropriate for intermediated securities transactions. In this respect, from the early stage the wording of innocent acquisition was selected, and the principle of the innocent acquisition protection was formulated with a neutral and fact-based structure.

As in Germany and Korea, Japan also operates different regimes for foreign securities transactions. Before discussing the new dematerialised intermediated system, this section briefly introduces the two different regimes for foreign securities. One regime addresses foreign securities listed on a Japanese exchange; the other deals with foreign securities traded outside Japan and held by Japanese investors through their local intermediary in Japan.

As emphasised above, the Korean intermediated system is designed resting on the property law model as the German system. Under the property law formulation, the fundamental principle in property transfer is that the specific subject matter of the transaction is directly transferred from the transferor to the transferee, keeping its identity without intermediate acquistion. In the intermediated system, this principle is reified by strict matching book-entries to the accounts of the transferor and the transferee. In addition, since the Korean intermediated system, as a method of encumbering security interests in securities, recognises only pledge (jilgweon), a priority issue does not occur in a complicated way. Like the primary priority rule of the Geneva Securities Convention, and Article 1209 of BGB, Article 333 of KCC provides the first-in-time rule for several interests of pledges over the same movable.

In the preceding Subsection, it was discussed that in the U.S. intermediated system, there exists no object of transfer; disposition of security entitlements involves mere extinguishment of relationship with the transferor’s intermediary, by debiting the amount of the security entitlements to her account, and creation of a new relationship with the transferee’s intermediary, by crediting the corresponding amount of the same type of security entitlements to her account; therefore, disposition of security entitlements are not transfer, as usually understood in a transaction of securities or other property. Accordingly, from the theoretical perspective itself, it may be impossible to trace the same object of the transaction, because there is no object of transfer. As drafters of UCC Article 8 justify, even because of the netting practice in a clearing and settlement process, presumably, it is almost impossible to trace the transferee of the same securities. Notwithstanding, in order to cut off adverse claims, and to protect acquirers including collateral takers, UCC Article 8 provides several mechanisms for fulfilling strong innocent acquisition.

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The metal dusting corrosion of Fe, Ni and Co and selected Ni-based and Fe-Ni based alloys in CO-H2 environments in the 400-850oC temperature range is discussed. Where possible, a mechanistic interpretation of the results is included. Based on the corrosion mechanism, control strategies are outlined. These include novel alloy development, the use of coatings and the use of additives to the process stream.

Metal dusting is a severe form of corrosive degradation that Fe, Co, and Ni base high-temperature alloys undergo when subjected to environments supersaturated with carbon (a c > l). This corrosion process leads to the break-up of bulk metal into metal powder. The present study focuses on the fundamental understanding of the corrosion of Fe in carbon-supersaturated environments over the temperature range 350-1050°C. Building on earlier research, the role of deposited carbon in triggering corrosion is further clarified. The corrosion rate peaks at ∼575°C with a sharp decrease in rate on either side of the maximum. High-resolution electron microscopy reveals, in addition to metal particles, a mixture of graphitic carbon, amorphous carbon, and filamentous carbon in the corrosion product. While the presence of a surface layer of Fe 3 C is characteristic of corrosion up to 850°C, such a layer is absent at the higher temperatures. The focus of this research is to understand reaction mechanisms by characterizing interfacial processes at the nano level.