Nickel molybdenum containing

Natural gas contains both organic and inorganic sulfur compounds that must be removed to protect both the reforming and downstream methanol synthesis catalysts. Hydrodesulfurization across a cobalt or nickel molybdenum—zinc oxide fixed-bed sequence is the basis for an effective purification system. For high levels of sulfur, bulk removal in a Hquid absorption—stripping system followed by fixed-bed residual clean-up is more practical (see Sulfur REMOVAL AND RECOVERY). Chlorides and mercury may also be found in natural gas, particularly from offshore reservoirs. These poisons can be removed by activated alumina or carbon beds. 

The catalyst for the second stage is also a bifimctional catalyst containing hydrogenating and acidic components. Metals such as nickel, molybdenum, tungsten, or palladium are used in various combinations and dispersed on sofid acidic supports such as synthetic amorphous or crystalline sihca—alumina, eg, zeofites. These supports contain strongly acidic sites and sometimes are enhanced by the incorporation of a small amount of fluorine. 

The first iron—nickel martensitic alloys contained ca 0.01% carbon, 20 or 25% nickel, and 1.5—2.5% aluminum and titanium. Later an 18% nickel steel containing cobalt, molybdenum, and titanium was developed, and still more recentiy a senes of 12% nickel steels containing chromium and molybdenum came on the market. 

The composition of this alloy (54% nickel, 15% molybdenum, 15% chromium, 5% tungsten and 5% iron) is less susceptible to intergranular corrosion at welds. The presence of chromium in this alloy gives it better resistance to oxidizing conditions than the nickel/molybdenum alloy, particularly for durability in wet chlorine and concentrated hypochlorite solutions, and has many applications in chlorination processes. In cases in which hydrochloric and sulfuric acid solutions contain oxidizing agents such as ferric and cupric ions, it is better to use the nickel/molybdenum/ chromium alloy than the nickel/molybdenum alloy. 

ASTM A 890/A 890M-99(2003) Standard Specification for Castings, Iron-Chromium-Nickel-Molybdenum Corrosion-Resistant, Duplex (Austenitic/Ferritic) for General Application (contains the major duplex grades)... 

One of the principal functions of alloying elements in steel, such as manganese, chromium, nickel, molybdenum, etc., is to increase the hardenabilitv. Whereas prodigious amounts of expensive alloys were formerly used to insure full hardening, especially in medium and heavy sections, wartime shortages focused attention on the use of as little alloy as possible within the hardenabilitv requirements. A large number of steels were developed containing relatively small additions of a number ol elements, and a number of these steels hav e continued in use. 

Nickel Promoted Catalysts. Nickel containing catalysts are known to be sensitive for too high temperatures. The Dutch patent 123195 (17) claims that active nickel-molybdenum-alumina catalysts are obtained, when nickel is impregnated first. The calcination is critical however. According to this patent, catalysts calcined at 480 are twice as active as catalysts, calcined at 650°C. 

The reappearance of Brdnsted acid sites has been observed for the high calcined nickel-molybdenum-alumina catalysts. The presence of a nickel aluminate phase has been concluded from the reflectance spectra. The second Lewis band (1612 cm l) has a very low intensity, in comparison with the cobalt containing catalysts of a same composition and after the same calcination conditions. 

In summary, fixed-bed processes have advantages in ease of scaleup and operation. The reactors operate in a downflow mode, with liquid feed trickling downward over the solid catalyst concurrent with the hydrogen gas. The usual catalyst is cobalt/molybdenum (Co/Mo) or nickel/molybdenum (Ni/Mo) on alumina (A1203) and contain 11-14% molybdenum and 2-3% of the promoter nickel or cobalt. The alumina typically has a pore volume of 0.5 ml/g. The catalyst is formed into pellets by extrusion, in shapes such as cylinders (ca. 2 mm diameter), lobed cylinders, or rings. 

Two Chevron catalysts were evaluated ICR 106 (containing nickel, tungsten, silica, and alumina) and ICR 113 (containing nickel, molybdenum, silica, and alumina) Although ICR 113 is somewhat less active than ICR 106, it is also a less expensive catalyst and, therefore, may be the catalyst of choice for cases in which lower severities of hydrogenation are needed. 

Two proprietary Chevron catalysts were used in different pilot plant simulations of the syncrude hydrotreater ICR 106 and ICR 113. The ICR 106 catalyst contains nickel, tungsten, silica, and alumina and the ICR 113 catalyst contains nickel, molybdenum, silica, and alumina. An equal volume of inert, nonporous alumina was placed on top of the catalysts. This alumina served as a preheating zone. These catalysts operated satisfactorily for over one-half year (4000 hours) with the Illinois H-Coal syncrude. 

Authentic and synthetic solvent-refined coal filtrates were processed upflow in hydrogen over three different commercially available catalysts. Residual (>850°F bp) solvent-refined coal versions up to 46 wt % were observed under typical hydrotreating conditions on authentic filtrate over a cobalt-molybdenum (Co-Mo) catalyst. A synthetic filtrate comprised of creosote oil containing 52 wt % Tacoma solvent-refined coals was used for evaluating nickel-molybdenum and nickel-tungsten catalysts. Nickel-molybdenum on alumina catalyst converted more 850°F- - solvent-refined coals, consumed less hydrogen, and produced a better product distribution than nickel-tungsten on silica alumina. Net solvent make was observed from both catalysts on synthetic filtrate whereas a solvent loss was observed when authentic filtrate was hydroprocessed. Products were characterized by a number of analytical methods. 

Comparison of the site densities from Table XIX with metal areas determined from H2 adsorption provides important insights into the nature of H2S adsorption on these catalysts. For example, the sulfur site density of 213 /tmol/g compared to the metal site density of 182 /rmol/g (from H2 adsorption) for 14% Ni/Al203 is equivalent to S/Nis = 0.6, in reasonable agreement with the earlier discussed studies (Section III,C) which show values of 0.5-0.8 and consistent with the value 0.6 determined for pure unsupported Ni. However, in the case of a typical molybdenum-containing catalyst, e.g., 10% Ni/20% Mo/A1203, the sulfur site density and H2 uptake are 693 and 72 /imol/g, respectively (S/Nis = 4.8), providing evidence that a considerable amount of sulfur adsorbs on molybdenum oxide sites which do not adsorb H2 a similar behavior is also observed for Raney Ni and nickel-boride catalysts. 

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