Coal Liquefaction Catalysts Research Articles

96/00171 Fundamental studies on red mud as a catalyst for coal liquefaction. Studies on active components in red mud and possibilities for improvement of its catalytic activities

96/00171 Fundamental studies on red mud as a catalyst for coal liquefaction. Studies on active components in red mud and possibilities for improvement of its catalytic activities

Functionalized Surfactants as Precursors to Dispersed Coal Liquefaction Catalysts

An oil-soluble coal liquefaction catalyst precursor was prepared by functionalizing (ion-exchangin) a commercially available anionic surfactant (Areosol OT-100, sodium dioctylsulfosuccinate) with Co, Ni or Fe. The Co and Ni forms of the sufactant produced catalysts that are active for coal liquefaction at low concentration even in a nondonor solvent, while the Fe produced the least effective catalyst

96/00194 Role of catalyst and solvent in coal liquefaction

96/00194 Role of catalyst and solvent in coal liquefaction

Effect of Preparation Conditions on the Characterization and Activity of Aerosol-Generated Ferric Sulfide-Based Catalysts for Direct Coal Liquefaction

Direct liquefaction of coal was studied using ferric sulfide-based catalysts generated in an aerosol reactor. The catalyst materials were prepared under varying conditions of temperature, pressure, and precursor concentration. In some runs, Fe−Cu−S mixed-metal catalysts containing 10 and 40% of Cu (based on total metal) were also used. Characterization studies reveal that the catalysts consist of hollow particles 3−20 nm in diameter, aggregated in clumps. Liquefaction experiments were performed at 350−440 °C under a hydrogen pressure of 1000 psi(cold) and 30 min reaction time with tetralin or phenanthrene as solvent. The catalyst activity and selectivity to oil-range products increase with increase in temperature of the aerosol reactor. The selectivity improves slightly when the catalyst exposure to air is minimized. The catalytic effects are more pronounced with phenanthrene as solvent. At 400 °C, both the conversion of coal and the oil yield increase with increase in catalyst loading, but the effect is ...

95/05816 Preparation and modification of recoverable particle catalysts for coal liquefaction

95/05816 Preparation and modification of recoverable particle catalysts for coal liquefaction

1-6.石炭液化反応における高分散触媒の役割(Session(1)石炭転換反応における触媒の役割)

1-6.石炭液化反応における高分散触媒の役割(Session(1)石炭転換反応における触媒の役割)

1-7.石炭液化における触媒の働き(Session(1)石炭転換反応における触媒の役割)

1-7.石炭液化における触媒の働き(Session(1)石炭転換反応における触媒の役割)

Deactivation of a coal liquefaction catalyst

A commercial coal liquefaction catalyst, Amocat 1A, has been subjected to a deactivation study in a laboratory catalytic coal liquefaction microreactor. Carbonaceous and metal deposits were the two major factors causing catalyst deactivation. The carbonaceous material deposited primarily in the interior of the catalyst particle and clogged the pores in a uniform manner. The metals deposit was rich in calcite and deposition was mostly restricted to the external surface of the catalyst particle. It appears that either mechanism operating alone will completely deactivate the catalyst after processing roughly 1000 weights of coal per weight of catalyst.

95/01331 Synthesis and characteristerization of coal liquefaction catalysts in Inverse micelles

95/01331 Synthesis and characteristerization of coal liquefaction catalysts in Inverse micelles

Exfoliated MoS2 catalysts in coal liquefaction

A technique is described for the application of MoS2 to coal particles. The method was used to determine the importance of several parameters to the performance of this direct coal liquefaction catalyst. Improved performance was obtained when MoS2 was intercalated with lithium, then exfoliated in a mixture of tetrahydrofuran and water in the presence of coal. Performance was compared by subjecting dried coal/catalyst mixtures to uniform microautoclave liquefaction tests. Measurements of coal conversion and hydrogen consumption show that a combination of reduction of the MoS2 stacking and improved coal/catalyst dispersion is beneficial.

酸化鉄触媒による予熱器へのスケール付着とその抑制の可能性

Iron catalysts have generally been used as a one through catalyst for coal liquefaction. However, in some cases, scale formation phenomenon on to the inner wall of the preheater and pipes has been reported.In this study, the conditions and mechanisms of scale formation, and possible method of prevention were investigated.Remarkable scale formation was not found in the experimental tests using pyrite catalyst, on the contrary, iron oxide catalyst system caused scale formation within some limited conditions.The scale formation mechanisms in the iron oxide catalyst system were inferred as follows:Fine iron compound is sulfurized by hydrogen sulfide in the preheating process, then becomes fine and active crystalline pyrrhotite.Fine pyrrhotite crystals combine into coarse crystal on the high temperature pipe wall (over 400°C) of the preheater and form the scale with inclusions of fine coal and inorganic particles.To prevent the scale formation in the iron oxide catalyst system, following measures are proposed ;·Maximum temperature of preheater wall has to keep under 400°C .·By surrounding an active pyrrhotite crystal with enough amount of coal molecules, coal molecules are adsorbed to the surface of fine pyrrhotite. Such condition arrests the growth to the coarse crystal of fine pyrrhotite crystal, and finally, the scale forma- tion is prevented.To achieve such condition, for example, the method of coal impregnated with fine iron oxide is considered to be effective.

Secondary Hydrogenation Catalyst for Brown Coal Liquefaction. Effect of preasphaltene and ash content on catalyst deactivation.

褐炭液化二次水添触媒として開発されたCa-Ni-Mo/Al2O3触媒について, 活性低下に及ぼすプレアスファルテンおよび灰分量の影響を調べ活性低下機構について考察した. Ni-Mo/Al2O3触媒に比べて, Ca-Ni-Mo/Al2O3触媒では炭素質の析出が少なく高濃度のプレアスファルテンを含む原料の場合でも活性低下が小さいことがわかった.いっぽう原料中灰分濃度が高い場合には著しい活性低下が認められ, 粒子径が小さなアルカリ金属を含む灰分は, 容易に触媒の内部まで侵入し活性点を毒すると考えられる.また反応器入口側で触媒物性の変化が大きいが, 細孔容積の低下は炭素質の析出に起因し, 灰分中の金属成分の蓄積により触媒細孔が閉塞する可能性は小さいことがわかった.これらの結果から, 運転初期の触媒への炭素質析出と灰分中のアルカリ金属 (Na, K) の蓄積が活性低下の原因であると考えられる.

Piliared montmorilionite catalysts for coal liquefaction

Piliared montmorilionite catalysts for coal liquefaction

Mechanisms of iron-based catalysis investigated using model compounds

The catalytic mechanism of highly active, nanophase, iron-based coal liquefaction catalysts was investigated using a series of model compounds. The iron-oxide phases ferric oxyhydroxysulfate (OHS), 6-line ferrihydrite, hematite, and goethite, were evaluated as catalyst precursors with systematically substituted diphenylmethanes in the presence of a hydrogen donating solvent. The activity of the catalysts was observed to be dependent upon the functionality on the model compounds. The results of these model compound studies and their relationship to possible reaction mechanisms are presented.

鉄系触媒の状態変化の熱力学的解析

Thermodynamic analyses were done for better understanding of the structural changes in iron based coal liquefaction catalysts during sulfidation and oxida-tion. Chemical potential diagrams were used to evaluate the stability/reactivity of several iron phases such as Fe, Fe3O4 (magnetite), Fe2O3 (hematite), Fe0.877S (Pyrrhotite), FeS2 (phyrite), FeSO4, and Fe2 (SO4) 3. These analyses indicated that most of the iron starting materials would be converted into thermodynamically stable phase Fe0.877S under typical coal liquefaction conditions, i.e., reaction temperature of 698K under reducing/sulfiding conditions. However, the sulfidation paths were quite different in Fe2O3 and FeSO4 as the starting materials, and were influenced significantly by the sul-fidation conditions, such as temperature, P (H2S) /P (H2) and P (H2O). These analyses suggested that steaming conditions would facilitate the sulfidation, but cause the gas phase transport of hydrated compounds, which might be one of the reasons for catalyst agglomeration.

Deactivation of a coal liquefaction catalyst

The effect of deasphalting of heavy oil with different degrees of asphaltenes precipitation on catalytic hydrotreating is reported in this work. Deasphalted oils were obtained in a pressurized vessel using n-heptane and n-pentane as solvents. Various samples with different amounts of asphaltenes were prepared by varying precipitation conditions. Hydrotreating of deasphalted oils was conducted with a commercial NiMo catalyst in a batch reactor at the following reaction conditions: hydrogen pressure of 100 kg/cm2, temperature of 400 °C, stirring rate of 750 rpm and reaction time of 4 h. The heavy oil, the deasphalted oils and the hydrotreated products were characterized by sulfur, metals (Ni, V), asphaltene contents, and API gravity. Metals and carbon contents as well as textural properties and X-ray diffraction were also determined on fresh, spent and regenerated catalysts.

Synthesis and Characterization of Coal Liquefaction Catalysts in Inverse Micelles

We have synthesized nanometer sized particles of Fe, Pd, and FeS 2 (pyrite) in inverse micelle solutions and tested the particles as catalysts in coal conversion processes. The synthesis procedure produces a variety of high surface area, highly dispersed, unsupported metal and metal compound catalysts. While Pd is used to test the viability of the particles formed by this synthesis technique, only disposable iron-based particles are of economic interest. The particles are prepared by reduction or chemical reaction of salts solubilized in microheterogeneous surfactant and oil solutions. Chemical manipulation produces metal powders. Particle size and composition are determined by transmission electron microscopy, electron diffraction, and UV-visible spectrophotometry. Catalysts in solution and as powders are explored in three reactions: the hydrogenolysis of naphthylbibenzylmethane, coal hydropyrolysis, and coal liquefaction

Development of a dispersed iron catalyst for first stage coal liquefication

A procedure yielding a very small particle size iron catalyst for coal liquefaction has been developed at the Pittsburgh Energy Technology Center. This procedure has two important components. The first is incipient wetness impregnation of coal with an aqueous solution of ferric nitrate (subsequently converted to hydrated iron oxide by contact with ammonium hydroxide). The second is proper time/temperature activation of the iron under a gaseous atmosphere of H 2/H 2S to produce pyrrhotite. In continuous operations, an optimum preliquefaction temperature of 275° C was observed for the activation of hydrated iron oxide in the presence of Illinois No. 6 coal. The net effect of proper implementation of this procedure was the development of a finely divided iron catalyst that exhibited high levels of activity in comparisons with molybdenum catalysts.

Laboratory evaluation of four coal liquefaction catalysts prepared from modified alumina supports

A blank alumina catalyst support was modified by deposition of TiO 2, ZrO 2 or carbon, and cobalt molybdate catalysts prepared from the modified supports were evaluated in a laboratory coal liquefaction microreactor unit. Performance was referenced to a commercial CoMo/alumina catalyst, Amocat 1A, which was derived from the same blank support. All catalysts possessed very similar pore structures, and thus the effect of pore structure was practically eliminated from the comparison. The effects of support modification on catalyst performance were found to be minimal.

Development of Highly Dispersed Coal Liquefaction Catalysts

The development of iron pentacarbonyl derived coal liquefaction catalyst is summarized. Iron pentacarbonyl derived catalyst is one of the most active catalysts for the hydroliquefaction of a variety of coal samples. When low sulfur content coal was employed, the addition of an equivalent amount of sulfur to iron was necessary in order to achieve high activity. The active species of iron carbonyl derived catalyst is attributed to pyrrhotite, some of which is of nanosize order as determined by XRD and Mossbauer spectroscopic investigation. Kinetic studies of coal liquefaction using iron carbonyl sulfur catalyst showed that the role of catalyst is to promote direct hydrogen-transfer process from gas phase to coal fragment radicals