CN101512674A - High-performance coating materials with improved resistance to metal dusting corrosion - Google Patents

Abstract

The present invention provides high performance coated metal compositions that are resistant to metal dusting corrosion and methods of providing such compositions. The coated metal composition is represented by the structure (PQR), wherein P is an oxide layer on the surface of (PQR), Q is a coating metal layer interposed between P and R, and R is a base metal. P comprises alumina, chromia, silica, mullite or mixtures thereof. Q comprises nickel and aluminum, and at least one element selected from the group consisting of Cr, Si, Mn, Fe, Co, B, C, N, P, Ga, Ge, As, In, Sn, Sb, Pb, Sc, La, Y, Ce, Ti, Zr, Hf, V, Nb, Ta, Mo, W, Ru, Rh, Ir, Pd, Pt, Cu, Ag, Au, and mixtures thereof. R is selected from the group consisting of carbon steel, low chromium steel, ferritic stainless steel, austenitic stainless steel, duplex stainless steel, Inconel, Incoloy, Fe-Ni based alloys, and Co based alloys. Advantages exhibited by the disclosed coated metal compositions include improved metal dusting corrosion resistance at high temperatures and in carbon supersaturated environments with relatively low oxygen partial pressures. The coated metal composition is suitable for use in syngas generation process equipment.

Description

High performance coating material with improved resistance to metal ash corrosion

field of invention

The present invention relates to the field of materials used in synthesis gas generation processes. More particularly, the invention relates to materials exposed to corrosive reactants and carbon supersaturated environments. More particularly, the present invention relates to coating material compositions and methods for controlling exposure to high carbon activity and relatively low oxygen activity in reactor systems, gas/gas heat exchanger systems, and synthesis gas process piping and piping equipment. Metal ash corrosion.

Background of the invention

One of the most abundant fossil fuels is natural gas, which is primarily methane. In high temperature processes involving the conversion of methane to high value products such as liquid hydrocarbons, chemicals such as ethylene, or the generation of electrical power, ambient conditions including very high carbon activity and relatively low oxygen activity are commonly encountered. Similar circumstances may also be encountered in many other syngas generation processes. High carbon activity and relatively low oxygen active environment. High temperature reactor materials, heat exchanger materials, syngas process piping and piping materials used in such processes degrade in service due to a very aggressive form of corrosion known as metal dusting. Metal ashing is at a temperature in the range of 350-10500°C, and in a carbon-supersaturated (carbon activity>1 ⁾ environment with a relatively low (about ^10-10-10-20 atmospheres) oxygen partial pressure, Fe, A detrimental form of high temperature corrosion experienced by Ni and Co based alloys. This form of corrosion is characterized by the disintegration of bulk metal into powder or dust. Most alloys that are commercially available today deteriorate due to this corrosion process.

Although many superalloys are designed to form chromium oxide ( _Cr2O3 ) surface films in situ in low oxygen partial pressure environments, in the presence of oxygen, at _high temperatures (i.e., >1000°C) chromia reacts to form _CrO3 , which is an alloy that vaporizes and evaporates causing loss of chromium. Chromium-depleted alloys are unable to form a protective chromium oxide film, so carbon enters the alloy from a highly reduced carbon-rich environment (with a carbon activity greater than 1). This leads to metal ash corrosion.

Aluminum and silicon are strong oxide formers that can be added to superalloys to improve corrosion resistance through the in situ formation of aluminum oxide and silicon dioxide surface films. However, excessive addition of these elements expected for excellent corrosion resistance often results in poor mechanical strength at high temperatures at which the alloy is used. Therefore, alloys containing excess aluminum and silicon cannot be used to construct components in the synthesis gas generation process.

Methods disclosed in the literature for controlling metal dusting corrosion include the use of gaseous inhibitors, such as _H2S . Inhibition by _H2S has two disadvantages. One is that _H2S tends to poison most catalysts used in hydrocarbon conversion processes. Second, _H2S must be removed from the outlet gas stream, which substantially increases operating costs.

US Patent 6,692,838 to Ramanarayanan et al. discloses anti-metal dusting compositions and methods for preventing metal dusting of metal surfaces exposed to carbon supersaturated environments. The composition includes (a) an alloy and (b) a protective oxide coating on the alloy. The alloy includes an alloy metal including a mixture of chromium and manganese and a base metal including iron, nickel and cobalt. The entire contents of US Patent 6,692,838 are incorporated herein by reference.

US Patent 6,737,175 to Ramanarayanan et al. discloses metal ashing resistant alloy compositions and methods for inhibiting metal ashing corrosion of metal surfaces exposed to supersaturated carbon environments. The method includes structuring a copper-based alloy surface, or coating a surface with a copper-based alloy. The entire contents of US Patent 6,737,175 are incorporated herein by reference.

US Patent Application 11/126,007, filed May 10, 2005 by Chun et al. also discloses alloy compositions and methods for preventing metal dusting of metal surfaces exposed to carbon supersaturated environments. The alloy composition comprises an alloy (PQR) and a multilayer (at least three layers) oxide film on the surface of the alloy (PQR), wherein the alloy (PQR) comprises a metal (P) selected from Fe, Ni, Co and mixtures thereof , including Cr, Mn, and alloy metals (Q) including Al, Si or Al/Si, and alloying elements (R). The multilayer oxide film is formed in situ during use of the alloy composition in a carbon supersaturated metal ashing environment. The entire contents of US patent application Ser. No. 11/126,007 are incorporated herein by reference.

There is a need for new alloys and surface coating materials that are resistant to metal ash corrosion. More specifically, there is a need for an advanced coating material composition in which the coated metal is exposed to low oxygen partial pressure (about 10 ⁻¹⁰ to about 10 ⁻²⁰ atmospheres) and carbon supersaturation (carbon activity >1) It is resistant to metal dusting corrosion, and includes the base metal that provides the required high temperature strength and other properties, such as creep strength and toughness, to the coated material. Such an advanced coating material composition should be able to form an outer protective oxide layer to prevent carbon migration by acting as a diffusion barrier for carbon ingress.

Contents of the invention

According to the disclosure of the present invention, an advantageous high-performance anti-metal ash corrosion coating material composition includes: (PQR), wherein P is an oxide layer on the surface of (PQR), and Q is an oxide layer inserted between P and R The coated metal layer, R is the basic metal layer, wherein P includes aluminum oxide, chromium oxide, silicon oxide, mullite or a mixture thereof, Q includes Ni and Al, and at least one selected from Cr, Si, Mn, Fe , Co, B, C, N, P, Ga, Ge, As, In, Sn, Sb, Pb, Sc, La, Y, Ce, Ti, Zr, Hf, V, Nb, Ta, Mo, W, Ru , Rh, Ir, Pd, Pt, Cu, Ag, Au and their mixture elements, R is selected from carbon steel, low chromium steel, ferritic stainless steel, austenitic stainless steel, duplex stainless steel, Inconel alloy ( Inconelalloy), Incoloy alloy, Fe-Ni based alloy, Ni based alloy and Co based alloy.

Another aspect of the present disclosure relates to an advantageous method of preventing metal dusting corrosion of metal surfaces exposed to carbon supersaturated environments, the method comprising a high performance coated metal composition (PQR), wherein P is in (PQR) Oxide layer on the surface, Q is the coated metal layer interposed between P and R, R is the base metal layer, where P includes aluminum oxide, chromium oxide, silicon oxide, mullite or mixtures thereof, and Q includes Ni and Al, and at least one selected from Cr, Si, Mn, Fe, Co, B, C, N, P, Ga, Ge, As, In, Sn, Sb, Pb, Sc, La, Y, Ce, Ti , Zr, Hf, V, Nb, Ta, Mo, W, Ru, Rh, Ir, Pd, Pt, Cu, Ag, Au and their mixture elements, R is selected from carbon steel, low chromium steel, ferritic stainless steel , austenitic stainless steel, duplex stainless steel, Inconel alloy, Incoloy alloy, Fe-Ni based alloy, Ni based alloy and Co based alloy; wherein the method comprises the step of providing (PQR) to the metal surface.

Many advantages and consequent uses/applications arise from advantageous high performance coating material compositions comprising (PQR), where P is the oxide layer on the surface of (PQR), Q is the coating located between P and R Metal layer, R is the base metal layer disclosed herein.

For example, in exemplary embodiments disclosed herein, high performance coating material compositions comprising (PQR) exhibit improved resistance to metallic dust at elevated temperatures and in carbon supersaturated environments with relatively low oxygen partial pressures. corrosive.

In additional exemplary embodiments of the present disclosure, high performance coating material compositions comprising (PQR) exhibit the ability to form a thermodynamically stable, slow growing, adherent inert oxide film that acts as a diffusion barrier to carbon ingress.

In additional exemplary embodiments of the present disclosure, high performance coating material compositions including (PQR) do not poison most catalysts used in hydrocarbon conversion processes.

In additional exemplary embodiments of the present disclosure, high performance coating material compositions including (PQR) result in improved adhesion of surface oxide films or layers, which increases spall resistance.

In additional exemplary embodiments disclosed herein, high performance coating material compositions including (PQR) result in reduced carbon deposition in carbon supersaturated environments.

In further exemplary embodiments of the present disclosure, the oxide layer (P) is formed on the surface of the high performance coating material composition including (PQR) when exposed to a metal ashing environment with low oxygen partial pressure.

In further exemplary embodiments of the present disclosure, an oxide layer (P) is formed in situ on the surface of the high performance coating material composition comprising (PQR) during use of the alloy in a carbon supersaturated environment.

In additional exemplary embodiments of the present disclosure, prior to use, the alloy is exposed to a carbon supersaturated low oxygen partial pressure environment or exposed to a controlled low oxygen partial pressure environment, including (PQR) An oxide layer (P) is formed on the surface of the high-performance coating material composition.

In another exemplary embodiment of the present disclosure, the coating metal layer (Q) on the surface of the high performance coating material composition including (PQR) has low porosity.

Another advantage of the high performance coating material composition comprising (PQR) is that if the protective surface oxide layer (P) breaks during use of the composition in a carbon supersaturated environment, the protective surface oxide layer (P) will reform in the crack to repair the oxide layer, thus protecting the alloy from metal ashing during service.

The disclosed high performance coating material compositions including (PQR) can be applied in syngas processing equipment which is in contact with carbon supersaturated environment at any time during its service, including reactors, gas/gas heat exchangers and Piping and piping for synthesis gas generation processes.

For protection, the disclosed high performance coating material composition comprising (PQR) can be provided to a surface by 1) constructing the device from (PQR), 2) co-extruding Q and R to form the surface of the device, Or 3) Coating Q on R to form a device surface exposed to a metal ashing environment.

These and other advantages, features and properties disclosed by the present invention and high performance coating material compositions including (PQR) and their advantageous applications and/or uses are read from the detailed description that follows, especially when combined with the accompanying It will be apparent when the graphs are read together.

Brief description of the drawings

To assist those of ordinary skill in the art pertaining to making and using its subject matter, reference is made to the accompanying drawings in which:

Fig. 1 is a schematic diagram depicting the high-performance surface coating material of the present invention for protecting syngas generation process equipment at various locations on piping or pipelines.

Figure 2 depicts a histogram of mass gain due to carbon deposition (a measure of metal ash corrosion) on Linde B polished alloys after reaction at 650°C in a 50CO- _50H2 gas mixture for 160 hours.

Figure 3 depicts a cross-sectional scanning electron microscope (SEM) image of an uncoated Inconel 601 alloy (prior art) corrosion surface after reaction at 650°C in a 50CO- _50H2 gas mixture for 160 hours.

Figure 4 depicts a cross-sectional SEM image of the corrosion surface of an uncoated Inconel 693 alloy (prior art) after reacting in a 50CO- _50H2 gas mixture at 650°C for 160 hours.

Figure 5 depicts the EDXS line profile of the high performance NiAl-coated Inconel 601 material of the present invention after testing at 1050°C in a 50CO- _50H2 gas mixture for 300 hours.

Figure 6 depicts the surface and cross-sectional SEM images of the high performance NiAl-coated Inconel 601 material of the present invention after testing at 1050°C in a 50CO- _50H2 gas mixture for 300 hours.

Figure 7 depicts the EDXS line profile of the high performance NiCrAl-coated Inconel 601 material of the present invention close to the coated surface before testing in a 50CO- _50H2 gas mixture at 1050°C for 300 hours.

Figure 8 depicts images of the surface and cross-section of the high performance NiCrAl-coated Inconel 601 material of the present invention close to the coated surface after testing at 1050°C in a 50CO- _50H2 gas mixture for 300 hours.

Figure 9 depicts the EDXS line profile of the inventive high performance NiCrAl coated 35/45 alloy close to the coated surface prior to testing at 1050°C in a 50CO- _50H2 gas mixture for 300 hours.

Figure 10 depicts images of the surface and cross-section of a high performance NiCrAl-coated 35/45 alloy of the present invention close to the coated surface after testing at 1050°C in a 50CO- _50H2 gas mixture for 300 hours.

Figure 11 depicts surface and cross-sectional images of a NiCrAl-coated Inconel 601 material (prior art) close to the coated surface after testing at 650°C in a 50CO- _50H2 gas mixture for 160 hours.

Detailed ways

The present invention relates to a high-performance coating material capable of forming a stable aluminum oxide surface film. The high-performance anti-metal ash corrosion coating material composition of the present invention differs from the prior art in that it includes a surface oxide layer, the coating metal on one side of the surface oxide layer, and the coating metal on the opposite side. The base metal flanking the oxide layer. More specifically, the coated metals of the present invention are distinguished from the prior art by improved adhesion of the surface oxide film or layer, which enables improved spall resistance. The coated metal of the present invention is also distinguished from the prior art by the improved adhesion of the base metal, which improves coating integrity. In addition, the coated metals of the present invention have reduced carbon deposition in carbon supersaturated environments relative to the prior art.

The high performance coating material compositions of the present invention provide distinct advantages over prior art alloy compositions useful as protective metal ash coatings on metal surfaces exposed to carbon supersaturated environments. The advantageous properties and/or characteristics of the disclosed high performance coating alloy compositions are based at least in part on the structure of the aluminum oxide film formed on the coated metal surface, which includes, inter alia, improved resistance to metal dusting corrosion, reduced carbon deposition , reduced propensity to poison catalysts used in hydrocarbon conversion processes, improved adhesion of in situ formed surface oxide films, improved resistance to spallation, improved resistance to carbon supersaturation when exposed to carbon supersaturated environments before and during use Ease of formation.

The high performance metal ash corrosion resistant coating material composition of the present invention is represented by the general formula (PQR). P is an oxide layer including alumina, chromia, silica, mullite and mixtures thereof. P forms the outer surface layer of the high performance coating material composition, so this layer is in direct contact with the carbon supersaturated low oxygen partial pressure environment. Adjacent to the oxide layer P is a coating metal Q comprising Ni and Al, and at least one selected from the group consisting of Cr, Si, Mn, Fe, Co, B, C, N, P, Ga, Ge, As, In , Sn, Sb, Pb, Sc, La, Y, Ce, Ti, Zr, Hf, V, Nb, Ta, Mo, W, Ru, Rh, Ir, Pd, Pt, Cu, Ag, Au and their mixtures element. Located on the opposite side of the coating metal layer Q is a base metal R selected from carbon steel, low chromium steel, ferritic stainless steel, austenitic stainless steel, duplex stainless steel, Inconel, Incoloy, Fe-Ni-based alloys, Ni-based alloys and Co-based alloys.

External oxide layer (P)

During use of the coating material in a carbon supersaturated environment, an oxide layer P forms in situ on the surface of the coating metal Q,. Alternatively, an oxide layer P is formed on the surface of the coating metal Q, prior to use by exposing the coating material to a carbon-supersaturated low oxygen partial pressure environment. Alternatively, an oxide layer P is formed on the surface of the coating metal Q, prior to use by exposing the coating material to a controlled low oxygen partial pressure environment.

The oxide layer P, is an oxide layer including aluminum oxide, chromium oxide, silicon oxide, mullite and mixtures thereof, and may contain some impurity oxides formed of elements constituting the coating metal Q and the base metal R. A preferred oxide layer P is aluminum oxide. The thickness of the oxide layer P ranges from at least about 1 nm to about 100 μm, preferably from at least about 10 nm to about 50 μm, more preferably from at least about 100 nm to about 10 μm.

An oxide layer P on the surface of the coated metal Q as described herein is formed on the coated metal surface by exposing the coating material to a metal ashing environment. A non-limiting example of a metal ashing environment is a gaseous 50CO: _50H2 mixture. The metal ashing environment can also contain other gases such as CH ₄ , NH ₃ , N ₂ , O ₂ , He, Ar and hydrocarbons, and can form stable gas on the coated metal Q including alumina, chromium oxide, silicon oxide, Oxide layers P of mullite and its mixtures. Thus, a protective oxide layer forms during or prior to the alloy's use under similar reaction conditions as it is exposed to a metal ashing environment. The preferred temperature range for the metal ashing environment is from about 350°C to about 1200°C, preferably from about 550°C to about 1200°C. Typical exposure times range from about 1 hour to about 500 hours, preferably from about 1 hour to about 300 hours, more preferably from about 1 hour to about 100 hours.

The oxide layer P described in this invention can also be formed on the surface of the coated metal Q by exposing the coating material to a controlled low oxygen partial pressure environment on the coated metal surface. Non-limiting examples of controlled low oxygen partial pressure environments are gaseous _H2O : _H2 mixtures and gaseous _CO2 :CO mixtures. The controlled low oxygen partial pressure environment can also include other gases such as CH ₄ , NH ₃ , N ₂ , O ₂ , He, Ar, and hydrocarbons, and can form stable carbon dioxide on the coated metal Q, including alumina, chromium oxide, Oxide layers P of silicon oxide, mullite and mixtures thereof. Therefore, before the alloy is used in a metal ashing environment, a protective oxide layer is formed. The controlled low oxygen partial pressure environment preferably has a temperature in the range of about 350°C to about 1200°C, preferably about 550°C to about 1200°C. Typical exposure times range from about 1 hour to about 500 hours, preferably from about 1 hour to about 300 hours, more preferably from about 1 hour to about 100 hours.

Coated metal layer (Q)

Coating metal Q includes Ni and Al, and at least one selected from Cr, Si, Mn, Fe, Co, B, C, N, P, Ga, Ge, As, In, Sn, Sb, Pb, Sc, La , Y, Ce, Ti, Zr, Hf, V, Nb, Ta, Mo, W, Ru, Rh, Ir, Pd, Pt, Cu, Ag, Au and their mixture elements. The coating metal compositions disclosed herein provide distinct advantages over prior art alloy compositions for use as protective metal ash coatings on metal surfaces exposed to carbon supersaturated environments. As non-limiting examples, alloying elements such as Sc, La, Y, and Ce, provide improved adhesion of the in situ formed surface oxide film, which contributes to enhanced spallation resistance. Alloying elements such as Ga, Ge, As, In, Sn, Sb, Pb, Pd, Pt, Cu, Ag, and Au provide reduced carbon deposition because these elements are non-catalytic for surface carbon transfer reactions.

The coating metal layer Q includes about 4 wt% to about 70 wt% aluminum, preferably about 4 wt% to about 50 wt% aluminum, more preferably about 4 wt% to about 30 wt% aluminum. In a preferred embodiment, the coating metal layer Q comprises less iron in the coating metal Q than in the base metal R. The coating metal Q includes less than about 12 wt % iron, preferably less than about 10 wt % iron, more preferably less than about 8 wt % iron. Coating metal Q comprising much more than 12 wt% iron results in poor metal dusting corrosion resistance in carbon supersaturated low oxygen partial pressure environments. Ni, which is a component of the coated metal layer, can also reduce the ashing corrosion rate because its ashing corrosion rate is about an order of magnitude lower than that of pure iron.

The coated metals of the present invention have low porosity which contributes to their improved resistance to carbon deposition in carbon supersaturated environments. Coating metal layer Q includes less than about 8 volume percent porosity, preferably less than about 3 volume percent porosity, more preferably less than about 2 volume percent porosity, and even more preferably less than 1 volume percent porosity. Excess porosity in the coating metal layer acts as a pathway for the transport of corrosive gases to the coating metal and base metal surfaces in the metal ashing environment. Carbon transport initiates carbon precipitation in the coating metal layer and delamination of the coating metal at the coating/base metal interface. Therefore, it is advantageous to achieve a coated metal layer comprising minimal porosity.

The low porosity coated metal layer can be formed by coating methods such as CVD, MOCVD, PVD, slurry coating, infiltration, overlay welding and plasma powder welding. The coating metal layer can be post annealed, or laser melted to achieve a high density coating. In contrast, conventional thermal spray methods, such as plasma, HVOF, and detonation guns, generally result in higher porosity coated metal layers. Conventional thermal spray coatings are produced by processes in which molten or softened particles are applied to the substrate by impact. The coating usually contains a lenticular or lamellar grain structure formed by the flattening of rapidly solidified small droplets striking a cold surface at high velocity. It is practically impossible to guarantee that all particles are exactly the same size, and it is impossible to achieve the same temperature and velocity. Therefore, during the thermal spraying process, the variation of the impact conditions of individual particles results in a non-uniform structured cermet layer comprising excess porosity.

Two preferred embodiments of the high performance coating material composition of the present invention include a coating metal Q comprising either (1) Ni and Al, or (2) Ni, Al, and Cr. The coating metal composition, NiAl, is an intermetallic phase known as the beta phase. The β-NiAl coating is applied to the base metal R by methods such as CVD, MOCVD, PVD, slurry coating, and infiltration. The thickness of β-NiAl is in the range of about 1 to about 300 μm, preferably about 1 to about 200 μm, more preferably about 1 to about 100 μm. The coating metal composition NiAl includes about 17 wt% to about 39 wt% aluminum, and about 61 wt% to about 83 wt% nickel. Preferably, the coating metal composition NiAl comprises about 18 wt% aluminum and about 82 wt% nickel. The coating metal composition, NiCrAl, may be applied to the base metal R by overlay welding methods such as plasma powder welding. The thickness of NiCrAl is in the range of about 100 μm to about 5 mm, preferably about 100 μm to about 4 mm, more preferably about 100 μm to about 3 mm. The coating metal composition NiCrAl includes about 4 wt% to about 10 wt% aluminum, about 15 wt% to about 30 wt% chromium, and about 60 wt% to about 81 wt% nickel. Preferably, coating metal Q includes about 6 wt% aluminum, about 25 wt% chromium and about 69 wt% nickel.

base metal(R)

The base metal R is selected from carbon steel, low chromium steel, ferritic stainless steel, austenitic stainless steel, duplex stainless steel, Inconel alloy, Incoloy alloy, Fe-Ni based alloy, Ni based alloy and Co based alloy. The base metal R may also be any commercially available alloy used in the construction of synthesis gas production process equipment. Non-limiting base metals, R, useful in the present invention are provided in Table 1. These base metals are suitable for making advantageous high performance coating materials (PQR) resistant to metal dusting corrosion.

Table 1:

base metal, R alloy UNS No. Alloy Composition (wt%) carbon steel 1018 G10180 The balance of Fe, 0.6-0.9 Mn, 0.14-0.20 C 4130 G41300 The balance of Fe, 0.35-0.60 Mn, 0.80-1.15 Cr, 0.27-0.34 C low chromium steel T11 K11562 Balance Fe: 1.25 Cr: 0.5 Mo, 0.5 Si, 0.3 Mn, 0.15 C, 0.045 P, 0.045 S T22 K21590 Balance Fe: 2.25 Cr: 1.0 Mo, 0.5 Si, 0.3 Mn, 0.15 C, 0.035 P, 0.035 S T5 S50100 Balance Fe: 5 Cr: 0.5 Mo, 0.5 Si, 0.3 Mn, 0.15 C, 0.04 P, 0.03 S T9 J82090 Balance Fe: 9 Cr: 1.0 Si, 0.35 Mn, 0.02 C, 0.04 P, 0.045 S ferritic stainless steel 409 S40900 Balance Fe: 10.5 Cr: 1.0 Si, 1.0 Mn, 0.5 Ni, 0.5 Ti, 0.08 C, 0.045 P, 0.045 S 410 S41000 Balance Fe: 11.5 Cr: 0.15 C, 0.045 P, 0.03 S

430 S43000 Balance Fe: 16.0 Cr: 1.0 Si, 1.0 Mn, 0.12 C, 0.045 P, 0.03 S Austenitic stainless steel 304 S30400 Balance Fe: 8 Ni: 18 Cr: 2.0 Mn, 0.75 Si, 0.08 C, 0.04 P, 0.03 S 310 S31000 Balance Fe: 19 Ni: 24 Cr: 2.0 Mn, 1.5 Si, 0.75 Mo, 0.25 C, 0.045 P, 0.03 S 253MA S30815 Balance Fe: 11 Ni: 21 Cr: 1.7 Si, 0.04 Ce, 0.17 N, 0.08 C RA85H S30615 Balance Fe: 14.5 Ni: 18.5 Cr: 3.5 Si: 1.0 Al, 0.2 C Duplex stainless steel 2205 S32205 Balance Fe: 4.5 Ni: 22 Cr: 2.0 Mn, 1.0 Si, 3.0 Mo, 0.03 C, 0.14 N, 0.03 P, 0.02 S 2507 S32507 Balance Fe: 6 Ni: 24 Cr: 1.2 Mn, 0.8 Si, 3.0 Mo, 0.5 Cu, 0.03 C, 0.2 N, 0.035 P, 0.02 S Inconel Alloy Inconel 600 N06600 Balance Ni: 8.0 Fe: 25.5 Cr, 0.08 Inconel 601 N06601 Balance Ni: 14.4 Fe: 23.0 Cr: 0.3 Mn: 1.4 Al, 0.5 Si, 0.1 C Inconel 602CA N/A Balance Ni: 9.5 Fe: 25.0 Cr: 2.2 Al, 0.18 C Inconel 690 N06690 Balance Ni: 9.0 Fe: 29.0 Cr: 0.3 Mn: 1.4 Al, 0.5 Si, 0.1 C Inconel 693 N06693 Balance Ni: 4.0 Fe: 29.0 Cr: 3.1 Al Inconel MA754 N/A Balance Ni: 9.0 Fe: 29.0 Cr: 0.3 Mn: 1.4 Al, 0.5 Si, 0.1 C Incoloy Incoloy 800H N08810 Balance Fe: 33.0 Ni: 21.0 Cr: 0.8 Mn: 0.5 Al: 0.4 Si: 0.5 Ti: 0.07 C

Incoloy 825 N08825 Balance Ni: 30.0 Fe: 21.5 Cr: 3.0 Mo: 2.2 Cu: 0.03 C Fe-Ni based alloy KHR-45A (35/45 Alloy) N/A Balance Fe: 43.6 Ni: 32.1 Cr: 1.0 Mn: 1.7 Si: 0.9 Nb: 0.1 Ti: 0.4 C Ni-based alloy Haynes 214 N07214 Balance Ni: 3.0 Fe: 2.0 Co: 16.0 Cr: 0.5 Mn: 4.5 Al: 0.2 Si: 0.5 Mo: 0.5 Ti: 0.05 C Co-based alloy Haynes 188 R30188 Balance Co: 22.0 Ni: 22.0 Cr: 3.0 Fe: 14.0 W: 0.04 La: 0.1 C MP35N R30035 Balance Co: 35.0 Ni: 20.0 Cr: 10.0 Mo

Formation method and application of high performance coating composition

The invention also discloses a method for preventing metal ashing on a metal surface exposed to a carbon supersaturated environment. The method can provide a high-performance coating material composition to a metal surface, wherein the material composition includes: (PQR), wherein P is an oxide layer on the surface of (PQR), and Q is a coating between P and R. Metal-clad layer, R is the basic metal layer, wherein P includes aluminum oxide, chromium oxide, silicon oxide, mullite or a mixture thereof, Q includes Ni and Al, and at least one selected from Cr, Si, Mn, Fe, Co , B, C, N, P, Ga, Ge, As, In, Sn, Sb, Pb, Sc, La, Y, Ce, Ti, Zr, Hf, V, Nb, Ta, Mo, W, Ru, Rh , Ir, Pd, Pt, Cu, Ag, Au and their mixture elements, R is selected from carbon steel, low chromium steel, ferritic stainless steel, austenitic stainless steel, duplex stainless steel, Inconel alloy, Inconel Roy alloy, Fe-Ni base alloy, Ni base alloy and Co base alloy.

At a temperature of 350-1050°C, in an environment with carbon supersaturation (carbon activity>1) and a relatively low oxygen partial pressure (about 10 ^-10 to about 10 ^-20 atmospheres), the metal surface to be protected can be protected by A high performance coating material can be constructed, coextruded with the coating material, coated with the coating material, or a combination of the three. In one embodiment of the present invention for providing a high performance coating material composition (PQR), the composition is formed by constructing process equipment from a coating metal layer Q and a base metal layer R. In another embodiment of the present invention for providing a high-performance coating material composition (PQR), the coating metal layer Q and the base metal Layer R, forming the composition. In yet another embodiment of the present invention for providing a high-performance coating material composition (PQR), the surface of the base metal R is coated with a coating metal Q by using coating techniques well known to those of ordinary skill in the art, from Existing surfaces of process equipment that are sensitive to metal ashing form the composition. Exemplary coating techniques suitable for coating base metal R with the coating metal compositions described herein include, but are not limited to, CVD, MOCVD, PVD, slurry coating, infiltration, plasma powder welding, thermal spraying, and sputtering. Accordingly, the high performance coating composition (PQR) of the present invention may either be constructed from, or co-extruded with, the high performance coating composition described herein, or be used The high performance coating material compositions described herein are coated.

The aforementioned protective surface oxide layer P can be formed in situ in a carbon supersaturated environment and during device operation. More precisely, for each of the three methods of forming the coated metal and base metal combination (QR), the protective surface oxide layer P can be formed during use when the device is exposed to metal ash environments (in situ form). Alternatively, the protective surface oxide layer P described above may be formed by exposing the coating metal and base metal combination (QR) to a carbon supersaturated environment prior to use of the device. An exemplary, but non-limiting, metal ashing environment is exposing the high performance coating material of the present invention to a metal dust environment, such as a 50CO:50H ₂ mixture. Alternatively, the aforementioned protective surface oxide layer P may be formed by exposing the coating metal and base metal combination (QR) to a controlled low oxygen partial pressure environment prior to use of the device. A non-limiting example of a controlled low oxygen partial pressure environment is exposing the high performance coating material of the present invention to a gaseous _H2O : _H2 mixture or a gaseous _CO2 :CO mixture. A preferred temperature range is from about 350°C to about 1200°C, preferably from about 550°C to about 1200°C. Typical exposure times range from about 1 hour to about 300 hours, preferably from about 1 hour to about 100 hours. Thus, the protective oxide coating, P, may be formed during or prior to the use of the alloy when the alloy is exposed to the reactive conditions of the metal ashing environment.

Equipment surfaces exposed to metal ashing environments can be constructed using the inventive high performance coating composition (PQR) described herein. Figure 1 schematically illustrates the use of coating materials (PQR) for syngas generation process equipment. By way of non-limiting example, the coating may be applied to the inside diameter, outside diameter, or inner and outer diameters of syngas process piping or piping, depending on the need for metal dusting corrosion resistance. Syngas processing equipment surfaces that benefit from the high performance coating materials of the present invention include equipment and reactor systems that come into contact with carbon supersaturated environments at any time during use. These equipment and reactor systems include, but are not limited to, reactors, gas/gas heat exchangers, and syngas generation process piping and piping.

Applicants attempt to disclose all reasonably contemplated implementations and applications of the disclosed subject matter. However, unforeseen, insubstantial variations remain equivalents of the present invention. While the invention has been described in conjunction with specific, exemplary embodiments thereof, it is evident that many variations, modifications and alterations would be possible in light of the foregoing description without departing from the spirit or scope of the invention disclosed herein. obvious to those of ordinary skill. Accordingly, the disclosure of the present invention is intended to embrace all such variations, modifications and variations from the foregoing detailed description.

The following examples illustrate the invention and its advantages without limiting the scope of the invention.

experiment method

The weight percent of elements in the material (PQR) was determined by standard energy dispersive X-spectrometry (EDXS) analysis. For the commercially available alloys (Inconel 601 and Inconel 693), rectangular samples of 0.5 inches by 0.25 inches by 0.06 inches were prepared from alloy sheets. β-NiAl-coated Inconel 601 samples were prepared by solid infiltration method. The base metal Inconel601 was subjected to chromizing treatment before the aluminizing infiltration process. A diffusion reaction was performed at about 800° C. to form a δ-Ni ₂ Al ₃ phase on the surface of the base metal Inconel 601. Subsequent heat treatment at 1079[deg.] C. converts the low-melting delta phase to the beta-NiAl phase, wherein the aluminum content ranges from about 17 to about 39 wt%. NiCrAl-coated Inconel 601 and NiCrAl-coated Alloy 35/45 samples were prepared by plasma powder welding method. As a comparative example, NiCrAl-coated Inconel 601 samples were prepared by air plasma spraying, conventional thermal spraying method. A 0.5 inch by 0.25 inch rectangular specimen was cut from the sample. The sample surface was polished to a 600 fine grain finish or a Linde B (0.05 micron alumina powder) finish and cleaned in acetone. Corrosion kinetics of various alloy samples were studied by exposing the samples to an environment of 50CO- _50H2 (volume%) for up to 300 hours at test temperatures ranging from 550°C to 1050°C. The carbon gain of the samples was measured using a Cahn 1000 electric balance. Carbon gain is an indicator of metal ash corrosion. The surfaces and sections of the samples were also examined using a scanning electron microscope (SEM).

Example

Example 1

According to the test method described above, the following alloy samples were tested: Inconel 601 (prior art), Inconel 693 (prior art), β-NiAl coated Inconel 601, NiCrAl coated Inconel 601 and NiCrAl coated 35 /45 alloy. The results of the weight measurements are shown in FIG. 2 . Figure 2 depicts the carbon deposition-induced mass gain (a measure of metal dusting corrosion) on Linde B polished alloys after 160 hours of reaction at 650°C in a 50CO- _50H2 gas mixture. After metal ash exposure, the surface of samples covered with carbon was always corroded with metal ash. Significant amounts of carbon deposition were measured on the surface of commercially available prior art alloys (Inconel 601 and Inconel 693). In contrast, negligible or minimal carbon deposition was measured on the inventive coated materials (β-NiAl coated Inconel 601, NiCrAl coated Inconel 601 and NiCrAl coated 35/45 alloy).

The susceptibility to metal ashing corrosion was further investigated by cross-sectional SEM examination of the corroded surface. The cross-sectional SEM image in Figure 3 shows that the prior art Inconel 601 alloy exhibits the characteristic pitted surface morphology after reaction at 650°C for 160 hours in a 50CO- _50H2 gas mixture. Metal powder in carbon deposits can be seen in the pits. The pit has a diameter of about 120 μm and a depth of about 20 μm. The cross-sectional SEM image in Figure 4 shows that the prior art Inconel 693 alloy exhibits the characteristic pitted surface morphology after reaction at 650°C for 160 hours in a 50CO- _50H2 gas mixture. Metal powder in carbon deposits can be seen in the pits. The pit has a diameter of about 12 μm and a depth of about 8 μm.

Example 2

Following the test method described above, the β-NiAl-coated Inconel 601 alloy was tested at 1050 °C for 300 hours in a 50CO- _50H gas mixture. Figure 5 depicts the EDXS line profile close to the surface of the coated material after testing. Concentrations of various elements (nickel, aluminium, chromium and iron) in wt% were plotted as a function of distance from the coating surface. Fig. 5 depicts the concentration distribution of the high performance coating material (PQR) according to the invention after a test at 1050°C for 300 hours in a 50CO-50H ₂ gas mixture. The oxide layer P consists of aluminum oxide. The thickness of the aluminum oxide layer is about 5 μm. Coating metal Q is β-NiAl with an aluminum content of about 18 wt%. The thickness of the β-NiAl layer is about 55 μm. In coating metal Q, the iron content was about 9.8 wt%. Also at the β-NiAl/Inconel 601 interface, a chromium-rich layer about 6 μm thick was observed. The base metal R is Inconel 601.

Figure 6 is the SEM image of the surface and cross-section of the same sample (β-NiAl coated Inconel 601) after testing at 1050°C for 300 hours in a 50CO-50H ₂ gas mixture. Depicted in Figure 6 are the aluminum oxide layer, the coating metal (NiAl) layer and the base metal (Inconel 601).

Example 3

NiCrAl-coated Inconel 601 was tested at 1050°C for 300 hours in a 50CO- _50H2 gas mixture following the test method described above. Figure 7 depicts the EDXS line distribution close to the surface of the coated material before testing. Concentrations of various elements (nickel, aluminium, chromium and iron) in wt% were plotted as a function of distance from the coating surface. Coating metal Q is NiCrAl comprising about 6 wt% aluminum, about 24 wt% chromium, about 68 wt% nickel and about 2 wt% iron. The thickness of the coating metal NiCrAl is about 2.1 mm. The base metal R is Inconel 601. Fig. 8 is a SEM image of the surface and cross-section of the same sample after being tested at 1050° C. for 300 hours in a 50CO-50H ₂ gas mixture. The oxide layer includes an approximately 3 μm thick layer of aluminum oxide and other oxides including chromia and alumina-chromia.

Example 4

Following the test method described above, the NiCrAl-coated 35/45 alloy was tested at 1050 °C for 300 hours in a 50CO- _50H2 gas mixture. Figure 9 depicts the EDXS line distribution close to the surface of the coated material before testing. Concentrations of various elements (nickel, aluminium, silicon, chromium and iron) expressed in wt% as a function of distance from the coating surface were plotted. Coating metal Q is NiCrAl, comprising about 5 wt% aluminum, about 26 wt% chromium, about 65 wt% nickel, about 1 wt% silicon, and about 3 wt% iron. The thickness of the coating metal NiCrAl is about 2.6 mm. The base metal R is a 35/45 alloy. Fig. 10 is a SEM image of the surface and section of the same sample after being tested at 1050°C for 300 hours in a 50CO-50H ₂ gas mixture. The oxide layer comprises an aluminum oxide layer about 4 μm thick.

Example 5: Comparative Example of High Porosity Coating

NiCrAlY-coated Inconel 601 samples were prepared by air plasma spray, conventional thermal spray method, following the test method described above. The NiCrAlY powder used was Praxair NI-278. The coating metal included about 69.2 wt% nickel, about 23.2 wt% chromium, about 6.9 wt% aluminum, and about 0.7 wt% yttrium. The coating metal NiCrAlY has a thickness of about 200 μm. Air plasma sprayed NiCrAlY coatings contain many pores between the solidified droplets and thus exhibit poor interfacial adhesion between the coated metal and the base alloy. The NiCrAlY-coated Inconel 601 alloy was tested in a 50CO- _50H2 gas mixture at 650 °C for 160 h. Figure 11 is a SEM image of the surface and cross-section of the same sample after testing. Excess porosity in the coating metal layer acts as a pathway for the transport of corrosive gases to the coating metal and base metal surfaces in the metal ashing environment. Carbon migration results in internal carbon deposition, expansion in the coating metal layer, and coating metal delamination at the coating/base metal interface. Nickel-rich particles were observed in this carbon deposit, which are characteristic of metal ash corrosion.

Claims (41)

1. A high-performance anti-metal dusting corrosion coating metal composition, which comprises (PQR), wherein P is the oxide layer on the (PQR) surface, Q is the coated metal layer interposed between P and R, R is the base metal, where P includes alumina, chromia, silica, mullite or mixtures thereof, Q includes Ni and Al, and at least one selected from Cr, Si, Mn, Fe, Co, B, C, N, P, Ga, Ge, As, In, Sn, Sb, Pb, Sc, La, Y, elements of Ce, Ti, Zr, Hf, V, Nb, Ta, Mo, W, Ru, Rh, Ir, Pd, Pt, Cu, Ag, Au and mixtures thereof, and R is selected from carbon steel, low chromium steel, ferritic stainless steel, austenitic stainless steel, duplex stainless steel, Inconel alloy, Incoloy alloy, Fe-Ni based alloy, Ni based alloy and Co based alloy. 2. The coated metal composition according to claim 1, wherein said oxide layer P is aluminum oxide. 3. The coated metal composition according to claim 1, wherein said oxide layer P is from about 1 nm to about 100 [mu]m thick. 4. The coated metal composition according to claim 1, wherein said coated metal layer Q comprises less than about 12 wt% iron. 5. The coated metal composition according to claim 1, wherein said coated metal layer Q comprises a porosity of less than about 3 volume percent. 6. The coated metal composition according to claim 5, wherein said coated metal layer Q comprises a porosity of less than about 1 volume percent. 7. The coated metal composition according to claim 4, wherein said coated metal layer Q comprises about 4 wt% to about 70 wt% aluminum. 8. The coated metal composition according to claim 7, said coating metal layer Q being NiAl. 9. The coated metal composition according to claim 8, wherein said coated metal layer Q comprises about 17 wt% to about 39 wt% aluminum, and about 61 wt% to about 83 wt% nickel. 10. The coated metal composition according to claim 9, wherein said coated metal layer Q is from about 1 [mu]m to about 300 [mu]m thick. 11. The coated metal composition according to claim 7, wherein said coating metal layer Q is NiCrAl. 12. The coated metal composition according to claim 11, wherein said coated metal layer Q comprises about 4 wt % to about 10 wt % of aluminum, about 15 wt % to about 30 wt % of chromium and about 60 wt % to about 81 wt % of nickel . 13. The coated metal composition according to claim 12, wherein said coated metal layer Q is about 100 [mu]m to about 5 mm thick. 14. The coated metal composition according to claim 1, wherein said coated metal composition (PQR) comprises a syngas generating process equipment surface exposed to a carbon supersaturated environment. 15. A coated metal composition according to claim 14, wherein said synthesis gas generating process equipment is selected from the group consisting of reactors, gas/gas heat exchangers, and process piping and piping. 16. A method of preventing metal dusting corrosion of a metal surface exposed to a carbon supersaturated environment comprising a high performance coated metal composition (PQR), wherein P is the oxide layer on the (PQR) surface, Q is the coated metal layer interposed between P and R, R is the base metal, where P includes alumina, chromia, silica, mullite or mixtures thereof, Q includes Ni and Al, and at least one selected from Cr, Si, Mn, Fe, Co, B, C, N, P, Ga, Ge, As, In, Sn, Sb, Pb, Sc, La, Y, elements of Ce, Ti, Zr, Hf, V, Nb, Ta, Mo, W, Ru, Rh, Ir, Pd, Pt, Cu, Ag, Au and mixtures thereof, and R is selected from carbon steel, low chromium steel, ferritic stainless steel, austenitic stainless steel, duplex stainless steel, Inconel alloy, Incoloy alloy, Fe-Ni based alloy, Ni based alloy and Co based alloy; The method described therein comprises the step of providing (PQR) to said metal surface. 17. The method according to claim 16, wherein said oxide layer P is aluminum oxide. 18. The method according to claim 16, wherein said oxide layer P is about 1 nm to about 100 [mu]m thick. 19. The method of claim 16, wherein, during or prior to use of said coated metal composition, said coated metal composition is exposed to a low oxygen partial pressure environment supersaturated with carbon, or exposed to a controlled The oxide layer P is formed in situ in a low oxygen partial pressure environment. 20. The method according to claim 19, wherein the carbon-supersaturated low oxygen partial pressure environment is a gaseous 50CO: _50H mixture at a temperature of about 350°C to about 1200°C for an exposure time of about 1 hour to about 500 Hour. 21. The method according to claim 20, wherein said carbon supersaturated low oxygen partial pressure environment further comprises a gas selected from the group consisting of _CH4 , _NH3 , _N2 , _O2 , He, Ar, hydrocarbons and mixtures thereof. 22. The method according to claim 19, wherein said controlled low oxygen partial pressure environment is a gaseous _H2O : _H2 mixture or a gaseous _CO2 :CO mixture at a temperature of about 350°C to about 1200°C, the contact time It is about 1 hour to about 500 hours. 23. The method of claim 22, wherein the controlled low oxygen partial pressure environment further comprises a gas selected from the group consisting of _CH4 , _NH3 , _N2 , _O2 , He, Ar, hydrocarbons, and mixtures thereof. 24. The method of claim 16, wherein said coating metal layer Q includes less than about 12 wt% iron. 25. The method of claim 16, wherein said coating metal layer Q includes a porosity of less than about 3 volume percent. 26. The method of claim 25, wherein said coating metal layer Q includes a porosity of less than about 1 volume percent. 27. The method of claim 24, wherein said coating metal layer Q comprises about 4 wt% to about 70 wt% aluminum. 28. The method according to claim 27, wherein said coating metal layer Q is NiAl. 29. The method of claim 28, wherein the coating metal layer Q comprises about 17 wt% to about 39 wt% aluminum, and about 61 wt% to about 83 wt% nickel. 30. The method according to claim 29, wherein said coating metal layer Q is about 1 [mu]m to about 300 [mu]m thick. 31. The method according to claim 30, wherein said step of providing (PQR) to the metal surface comprises a step selected from the group consisting of: a) constructing said metal surface from said high performance coating metal composition (PQR), b) co-extruding said metal layer Q on said base metal layer R, c) coating said metal layer Q on said base metal layer R, and d) Combination of steps a), b) and c). 32. The method according to claim 31, wherein said coating step c) is selected from CVD, MOCVD, PVD, slurry coating and infiltration. 33. The method according to claim 32, further comprising the step of post heat treatment or laser melting of said metal layer (Q). 34. The method according to claim 27, wherein said coating metal layer Q is NiCrAl. 35. The method of claim 34, wherein the coating metal layer Q comprises about 4 wt% to about 10 wt% aluminum, about 15 wt% to about 30 wt% chromium, and about 60 wt% to about 81 wt% nickel. 36. The method according to claim 35, wherein said coating metal layer Q is about 100 [mu]m to about 5 mm thick. 37. The method according to claim 36, wherein said step of providing (PQR) to the metal surface comprises a step selected from the group consisting of: a) constructing said metal surface from said high performance coating metal composition (PQR), b) co-extruding said metal layer Q on said base metal layer R, c) coating said metal layer Q on said base metal layer R, and d) Combination of steps a), b) and c). 38. The method according to claim 37, wherein said coating step c) is powder plasma welding. 39. Method according to claim 38, further comprising the step of post-heat treatment or laser melting of said metallic layer (Q). 40. The method of claim 16, wherein said coating metal composition (PQR) comprises surfaces of syngas generation processing equipment exposed to a carbon supersaturated environment. 41. The method according to claim 40, wherein said syngas production processing equipment is selected from the group consisting of reactors, gas/gas heat exchangers, and process piping and piping.

Images