148 research outputs found
The synthesis of higher alcohols from CO2 hydrogenation over Mn-Cu-K modified Fe5C2 and CuZnAlZr tandem catalysts
The catalytic production of higher alcohols (HAs) is a promising path for converting CO2 into value-added chemical products. The application is still limited by the low selectivity of HAs (less than 10%) on most catalysts. Here, we report a tandem catalyst consisting of Mn-Cu-K modified iron carbide and CuZnAlZr catalyst. The modification of iron carbide with Mn, Cu and K promoters improves the formation of HAs (13.5% Sel.), and the construction of tandem catalysts with CuZnAlZr can further enhance the catalytic performance. By examining different catalyst filling methods and the filling ratio of the tandem catalyst, it was found that the powder mixing resulted in a higher selectivity of HAs with a mass ratio of the two components of 1:1, and a synergistic effect leads to a higher selectivity of HAs (15.5%) with about 40% of propanol and butanol among HAs
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Novel bimetallic dispersed catalysts for temperature-programmed coal liquefaction. Final report
Development of new catalysts is a promising approach to more efficient coal liquefaction. It has been recognized that dispersed catalysts are superior to supported catalysts for primary liquefaction of coals, because the control of initial coal dissolution or depolymerization requires intimate contact between the catalyst and coal. This research is a fundamental and exploratory study on catalytic coal liquefaction, with the emphasis on exploring novel bimetallic dispersed catalysts for coal liquefaction and the effectiveness of temperature-programmed liquefaction using dispersed catalysts. The primary objective of this research was to explore novel bimetallic dispersed catalysts from organometallic molecular precursors, that could be used in low concentrations but exhibit relatively high activity for efficient hydroliquefaction of coals under temperature-programmed conditions. We have synthesized and tested various catalyst precursors in liquefaction of subbituminous and bituminous coals and in model compound studies to examine how do the composition and structure of the catalytic precursors affect their effectiveness for coal liquefaction under different reaction conditions, and how do these factors affect their catalytic functions for hydrogenation of polyaromatic hydrocarbons, for cleavage of C-C bonds in polycyclic systems such as 4-(1-naphthylmethyl)bibenzyl, for hydrogenolysis of C-O bond such as that in dinaphthylether, for hydrodeoxygenation of phenolic compounds and other oxygen-containing compounds such as xanthene, and for hydrodesulfurization of polycyclic sulfur compounds such as dibenzothiophene. The novel bimetallic and monometallic precursors synthesized and tested in this project include various Mo- and Fe-based compounds
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Novel bimetallic dispersed catalysts for temperature-programmed coal liquefaction. Technical progress report, April--June 1995
Coal liquefaction involves cleavage of methylene, dimethylene and ether bridges connecting polycyclic aromatic units and the reactions of various oxygen functional groups. Here in this quarterly, we report on our continued effort on hydrodeoxygenation of O-containing polycyclic model compounds using novel organometallic catalyst precursors. Compounds containing oxygen functional groups, especially phenols, are undesirable components of coal-derived liquids. Removal of these compounds from the products of coal liquefaction is required. A beneficial alternative would be the removal of these compounds, or the prevention of their formation, during the liquefaction reaction itself, rather than as a separate processing step. A novel organometallic catalyst precursor containing Co and Mo has been studied as a potential hydrogenation catalyst for coal liquefaction. To ascertain the hydrodeoxygenation activity of this catalyst under liquefaction conditions, model compounds were investigated. Anthrone, 2,6-di-t-butyl-4-methyl-phenol, dinaphthyl ether, and xanthene were reacted in the presence of the Co-Mo catalyst precursor and a precursor containing only Mo over a range of temperatures, providing a comparison of conversions to deoxygenated products. These conversions give an indication of the hydrodeoxygenating abilities of organometallic catalyst precursors within a coal liquefaction system. For example, at 400{degrees}C dinaphthylether was converted 100% (4.5% O-containing products) in the presence of the Co-Mo organometallic precursor, compared to 76.5% conversion (7.4% O-products) in the presence of the Mo catalyst
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Novel bimetallic dispersed catalysts for temperature-programmed coal liquefaction. Technical progress report, April--June 1996
This quarterly report describes our recent work on two related subjects: effect of using organometallic catalyst precursor on hydrodeoxygenation under coal liquefaction conditions, and the effect of mineral matters in liquefaction reactions of coals. Oxygen functionalities, especially phenols, are undesirable components of coal derived liquids. Removal of these compounds from the products of coal liquefaction is required. A beneficial alternative would be the removal of these functionalities, or the prevention of their formation, during the liquefaction process. Organometallic precursors of Co, Ni and Mo have been studied as catalysts. To ascertain the hydrodeoxygenation properties of these catalysts under liquefaction conditions, model compounds were investigated. Anthrone, Dibutylmethyl phenol, dinaphthyl ether and xanthene were studied to provide a comparison of conversions to deoxygenated products. Studies of the deoxygenating abilities of these catalyst precursors in coal liquefaction systems have also been performed. Improvements in conversion and product quality are observed. Both these factors are dependent on the coal used. It is also considered that some mineral matters in coal may have catalytic actions. Demineralization by successive HCl/HF treatments of a low rank coal has demonstrated that removal of the inherent mineral matter imparts no serious detrimental effect upon low temperature liquefaction. It appears that elimination of such species allows for better access for gaseous H{sub 2}, as suggested by previous studies
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Refinery Integration of By-Products from Coal-Derived Jet Fuels
The final report summarizes the accomplishments toward project goals during length of the project. The goal of this project was to integrate coal into a refinery in order to produce coal-based jet fuel, with the major goal to examine the products other than jet fuel. These products are in the gasoline, diesel and fuel oil range and result from coal-based jet fuel production from an Air Force funded program. The main goal of Task 1 was the production of coal-based jet fuel and other products that would need to be utilized in other fuels or for non-fuel sources, using known refining technology. The gasoline, diesel fuel, and fuel oil were tested in other aspects of the project. Light cycle oil (LCO) and refined chemical oil (RCO) were blended, hydrotreated to removed sulfur, and hydrogenated, then fractionated in the original production of jet fuel. Two main approaches, taken during the project period, varied where the fractionation took place, in order to preserve the life of catalysts used, which includes (1) fractionation of the hydrotreated blend to remove sulfur and nitrogen, followed by a hydrogenation step of the lighter fraction, and (2) fractionation of the LCO and RCO before any hydrotreatment. Task 2 involved assessment of the impact of refinery integration of JP-900 production on gasoline and diesel fuel. Fuel properties, ignition characteristics and engine combustion of model fuels and fuel samples from pilot-scale production runs were characterized. The model fuels used to represent the coal-based fuel streams were blended into full-boiling range fuels to simulate the mixing of fuel streams within the refinery to create potential 'finished' fuels. The representative compounds of the coal-based gasoline were cyclohexane and methyl cyclohexane, and for the coal-base diesel fuel they were fluorine and phenanthrene. Both the octane number (ON) of the coal-based gasoline and the cetane number (CN) of the coal-based diesel were low, relative to commercial fuels ({approx}60 ON for coal-based gasoline and {approx}20 CN for coal-based diesel fuel). Therefore, the allowable range of blending levels was studied where the blend would achieve acceptable performance. However, in both cases of the coal-based fuels, their ignition characteristics may make them ideal fuels for advanced combustion strategies where lower ON and CN are desirable. Task 3 was designed to develop new approaches for producing ultra clean fuels and value-added chemicals from refinery streams involving coal as a part of the feedstock. It consisted of the following three parts: (1) desulfurization and denitrogenation which involves both new adsorption approach for selective removal of nitrogen and sulfur and new catalysts for more effective hydrotreating and the combination of adsorption denitrogenation with hydrodesulfurization; (2) saturation of two-ring aromatics that included new design of sulfur resistant noble-metal catalysts for hydrogenation of naphthalene and tetralin in middle distillate fuels, and (3) value-added chemicals from naphthalene and biphenyl, which aimed at developing value-added organic chemicals from refinery streams such as 2,6-dimethylnaphthalene and 4,4{prime}-dimethylbiphenyl as precursors to advanced polymer materials. Major advances were achieved in this project in designing the catalysts and sorbent materials, and in developing fundamental understanding. The objective of Task 4 was to evaluate the effect of introducing coal into an existing petroleum refinery on the fuel oil product, specifically trace element emissions. Activities performed to accomplish this objective included analyzing two petroleum-based commercial heavy fuel oils (i.e., No. 6 fuel oils) as baseline fuels and three co-processed fuel oils, characterizing the atomization performance of a No. 6 fuel oil, measuring the combustion performance and emissions of the five fuels, specifically major, minor, and trace elements when fired in a watertube boiler designed for natural gas/fuel oil, and determining the boiler performance when firing the five fuels. Two different co-processed fuel oils were tested: one that had been partially hydrotreated, and the other a product of fractionation before hydrotreating. Task 5 focused on examining refining methods that would utilize coal and produce thermally stable jet fuel, included delayed coking and solvent extraction. Delayed coking was done on blends of decant oil and coal, with the goal to produce a premium carbon product and liquid fuels. Coking was done on bench scale and large laboratory scale cokers. Two coals were examined for co-coking, using Pittsburgh seam coal and Marfork coal product. Reactions in the large, laboratory scaled coker were reproducible in yields of products and in quality of products. While the co-coke produced from both coals was of sponge coke quality, minerals left in the coke made it unacceptable for use as anode or graphite grade filler
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Effects of low-temperature catalytic pretreatments on coal structure and reactivity in liquefaction. Final technical report, Volume 2 - hydrogenative and hydrothermal pretreatments and spectroscopic characterization using pyrolysis-GC-MS, CPMAS {sup 13}C NMR and FT-IR
It has been indicated by DOE COLIRN panel that low-temperature catalytic pretreatment is a promising approach to the development of an improved liquefaction process. This work is a fundamental study on effects of pretreatments on coal structure and reactivity in liquefaction. The main objectives of this project are to study the coal structural changes induced by low-temperature catalytic and thermal pretreatments by using spectroscopic techniques; and to clarify the pretreatment-induced changes in reactivity or convertibility of coals. As the second volume of the final report, here we summarize our work on spectroscopic characterization of four raw coals including two subbituminous coals and two bituminous coals, tetrahydrofuran (THF)-extracted but unreacted coals, the coals (THF-insoluble parts) that have been thermally pretreated. in the absence of any solvents and in the presence of either a hydrogen-donor solvent or a non-donor solvent, and the coals (THF-insoluble parts) that have been catalytically pretreated in the presence of a dispersed Mo sulfide catalyst in the absence of any solvents and in the presence of either a hydrogen-donor solvent or a non-donor solvent
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Refinery Integration of By-Products from Coal-Derived Jet Fuels
This report summarizes the accomplishments toward project goals during the second six months of the third year of the project to assess the properties and performance of coal based products. These products are in the gasoline, diesel and fuel oil range and result from coal based jet fuel production from an Air Force funded program. Specific areas of progress include generation of coal based material that has been fractionated into the desired refinery cuts and examination of carbon material, the use of a research gasoline engine to test coal-based gasoline, and modification of diesel engines for use in evaluating diesel produced in the project. At the pilot scale, the hydrotreating process was modified to separate the heavy components from the LCO and RCO fractions before hydrotreating in order to improve the performance of the catalysts in further processing. Characterization of the gasoline fuel indicates a dominance of single ring alkylcycloalkanes that have a low octane rating; however, blends containing these compounds do not have a negative effect upon gasoline when blended in refinery gasoline streams. Characterization of the diesel fuel indicates a dominance of 3-ring aromatics that have a low cetane value; however, these compounds do not have a negative effect upon diesel when blended in refinery diesel streams. Both gasoline and diesel continue to be tested for combustion performance. The desulfurization of sulfur containing components of coal and petroleum is being studied so that effective conversion of blended coal and petroleum streams can be efficiently converted to useful refinery products. Activated carbons have proven useful to remove the heavy sulfur components, and unsupported Ni/Mo and Ni/Co catalysts have been very effective for hydrodesulfurization. Equipment is now in place to begin fuel oil evaluations to assess the quality of coal based fuel oil. Combustion and characterization of the latest fuel oil (the high temperature fraction of RCO from the latest modification) indicates that the fraction is heavier than a No. 6 fuel oil. Combustion efficiency on our research boiler is {approx}63% for the heavy RCO fraction, lower than the combustion performance for previous co-coking fuel oils and No. 6 fuel oil. An additional coal has been procured and is being processed for the next series of delayed co-coking runs. Work continues on characterization of liquids and solids from co-coking of hydrotreated decant oils; liquid yields include more saturated and hydro- aromatics, while the coke quality varies depending on the conditions used. Pitch material is being generated from the heavy fraction of co-coking. Investigation of coal extraction as a method to produce RCO continues; the reactor modifications to filter the products hot and to do multi-stage extraction improve extraction yields from {approx}50 % to {approx}70%. Carbon characterization of co-cokes for use as various carbon artifacts continues
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Refinery Integration of By-Products from Coal-Derived Jet Fuels
This report summarizes the accomplishments toward project goals during the second six months of the third year of the project to assess the properties and performance of coal based products. These products are in the gasoline, diesel and fuel oil range and result from coal based jet fuel production from an Air Force funded program. Specific areas of progress include generation of coal based material that has been fractionated into the desired refinery cuts and examination of carbon material, the use of a research gasoline engine to test coal-based gasoline, and modification of diesel engines for use in evaluating diesel produced in the project. At the pilot scale, the hydrotreating process was modified to separate the heavy components from the LCO and RCO fractions before hydrotreating in order to improve the performance of the catalysts in further processing. Characterization of the gasoline fuel indicates a dominance of single ring alkylcycloalkanes that have a low octane rating; however, blends containing these compounds do not have a negative effect upon gasoline when blended in refinery gasoline streams. Characterization of the diesel fuel indicates a dominance of 3-ring aromatics that have a low cetane value; however, these compounds do not have a negative effect upon diesel when blended in refinery diesel streams. Both gasoline and diesel continue to be tested for combustion performance. The desulfurization of sulfur containing components of coal and petroleum is being studied so that effective conversion of blended coal and petroleum streams can be efficiently converted to useful refinery products. Activated carbons have proven useful to remove the heavy sulfur components, and unsupported Ni/Mo and Ni/Co catalysts have been very effective for hydrodesulfurization. Equipment is now in place to begin fuel oil evaluations to assess the quality of coal based fuel oil. Combustion and characterization of the latest fuel oil (the high temperature fraction of RCO from the latest modification) indicates that the fraction is heavier than a No. 6 fuel oil. Combustion efficiency on our research boiler is {approx}63% for the heavy RCO fraction, lower than the combustion performance for previous co-coking fuel oils and No. 6 fuel oil. An additional coal has been procured and is being processed for the next series of delayed co-coking runs. Work continues on characterization of liquids and solids from co-coking of hydrotreated decant oils; liquid yields include more saturated and hydro- aromatics, while the coke quality varies depending on the conditions used. Pitch material is being generated from the heavy fraction of co-coking. Investigation of coal extraction as a method to produce RCO continues; the reactor modifications to filter the products hot and to do multi-stage extraction improve extraction yields from {approx}50 % to {approx}70%. Carbon characterization of co-cokes for use as various carbon artifacts continues
CO{sub 2} Capture from Flue Gas Using Solid Molecular Basket Sorbents
The objective of this project is to develop a new generation of solid, regenerable polymeric molecular basket sorbent (MBS) for more cost-efficient capture and separation of CO{sub 2} from flue gas of coal-fired power plants. The primary goal is to develop a cost-effective MBS sorbent with better thermal stability. To improve the cost-effectiveness of MBS, we have explored commercially available and inexpensive support to replace the more expensive mesoporous molecular sieves like MCM-41 and SBA- 15. In addition, we have developed some advanced sorbent materials with 3D pore structure such as hexagonal mesoporous silica (HMS) to improve the CO{sub 2} working capacity of MBS, which can also reduce the cost for the whole CO{sub 2} capture process. During the project duration, the concern regarding the desorption rate of MBS sorbents has been raised, because lower desorption rate increases the desorption time for complete regeneration of the sorbent which in turn leads to a lower working capacity if the regeneration time is limited. Thus, the improvement in the thermal stability of MBS became a vital task for later part of this project. The improvement in the thermal stability was performed via increasing the polymer density either using higher molecular weight PEI or PEI cross-linking with an organic compound. Moreover, we have used the computational approach to estimate the interaction of CO{sub 2} with different MBSs for the fundamental understanding of CO{sub 2} sorption, which may benefit the development, design and modification of the sorbents and the process
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