Energy transport in carbohydrates. Part III. Chemical effects of γ-radiation on the cycloamyloses

Alcohol Production from Carbon Dioxide: Methanol as a Fuel and Chemical Feedstock

Kinetic, products distribution, and mechanism analysis for the pyrolysis of polyglycolic acid toward carbon cycle

The primary goal of this study was to explore the fundamental chemical processes occurring during a pulsed electrical discharge in liquid methanol. To this end, advanced analytical techniques were used to identify and, when possible, quantify gas and liquid methanol decomposition products. The effects of applied voltage, voltage polarity, and presence of water on the reaction stoichiometry and the selectivity for the identified gas products were also studied. Density Functional Theory (DFT) simulations were used to determine the most feasible thermal reaction pathways between 300 and 4000 K responsible for the formation of experimentally identified gas and liquid products. From these results, the key chemical reaction pathways were theorized and a reaction mechanism was developed. Gas products of plasma‐induced decomposition of methanol that were detected and quantified include hydrogen, carbon monoxide, carbon dioxide, methane, acetylene, ethylene, and ethane. The reaction selectivity was the highest for the former two compounds regardless of the applied voltage, discharge polarity or presence of water in the starting solution. Results also showed that the applied voltage, discharge polarity and presence of water had no effect on the types of reaction products. Liquid methanol decomposition products that where identified include ethanol, ethylene glycol, formaldehyde, acetic acid, allyl alcohol, 1‐propanol, 3‐buten‐1‐ol, 3‐butyn‐1‐ol, glycolaldehyde, and methyl glycolate. The chemical reaction mechanism that was proposed to explain the formation of the experimentally verified gas products offers specific pathways for the production of carbon monoxide and short‐chained hydrocarbons. In contrast, the reactions leading to the formation of hydrogen, carbon dioxide, and liquid products appear to be random. In general, recombination reactions of direct methanol decomposition products are largely responsible for the formation of C1 and C2 liquid products. Step‐wise reactions of those compounds with single or multiple carbon‐based radicals grow the molecular chain length to up to four carbon atoms thereby producing C4 compounds.

The pyrolysis of southern pine, red oak, and sweet gum sawdust is reported. Pyrolysis experiments were conducted under either a helium or nitrogen atmosphere at ∼371−871 °C, to determine the balance between liquid and gas products. Gas- and liquid-phase pyrolysis products were identified using gas chromatography (GC) and GC/mass spectrometry (MS). A total of 109 liquid and 40 gas compounds were identified. A total of 59 chemical compounds (35 liquids and 24 gaseous products) were quantitatively determined. The influence of the gas-phase residence time and biomass feed particle size were studied. The gas residence time determined the extent of secondary reactions. Very short residence times enhanced liquid production versus gas production. Particle sizes (d < 105 μm, 105 μm < d < 149 μm, 149 μm < d < 297 μm, and d > 297 μm) did not have a pronounced effect on either the yield or product distributions, indicating that heat-transfer limitations within the particles were negligible. The pyrolysis of pine, red oak, and sweet gum sawdust yielded similar product distributions. Simulations were conducted using the ASPEN/SP software package based on Gibbs energy minimization. At high temperatures, dominant species were hydrogen and carbon monoxide, while at lower temperatures, methane, carbon dioxide, and water were the predominant species. Above 871 °C, further increases in the temperature did not affect the product distribution. Lower gasification temperatures and higher steam/carbon ratios resulted in higher hydrogen and carbon monoxide production.

Effect of reaction conditions on pyrolysis of chlorogenic acid

CO2 electroreduction to multicarbon products from carbonate capture liquid

This DOE Phase I SBIR project has developed a glow discharge-based plasma process to convert carbon dioxide to sold carbon and water. By adding natural gas, the additional enthalpy can be used to reform the output carbon dioxide to value added carbon and EPA-compliance-grade water, thus creating a process that has no gaseous products at all, such as: CO2 + CH4  2C + 2H2O , which is simply the exothermic reverse of the syngas reaction. During the Phase I work, several milestones were accomplished successfully. a. First, a synthesis reactor was designed, assembled, and successfully operated using the combined simultaneous operation of glow discharge and microwaves. DC discharge and microwaves can also be operated individually, allowing multiple configurations to be used This is one of the first reactors of its kind, and perhaps the first ever. b. Second, the research team successfully produced carbon nanomaterials using carbon dioxide as the source of carbon via CO2 + 2H2  C + 2H2O. This is certainly one of the first processes to use plasma to convert carbon dioxide to nanocarbon, and perhaps the first ever demonstration. c. Third, it was also shown that carbon monoxide and carbon dioxide can be used with methane to reduce the synthesis temperature of ASI graphene decorated carbon nanotubes (GDCNT). Hitherto GDCNT were only fabricated above 1200 oC. GDCNT was synthesized at 780 oC. CO2 + C- 2CO; 2 CO + CH4 -- 3 C + 2H2O, and also, CH4 + CO2  2 C + 2H2O. d. Fourth, closed cycle synthesis of nanomaterial was demonstrated with over 80% conversion of carbon dioxide to carbon and water was achieved, on the basis of pressure drop during glow discharge. e. Fifth, plasma operation was achieved via glow discharge and microwaves at 500 Torr, demonstrating a path forward to atmospheric pressure operation f. Sixth, using carbon monoxide and carbon dioxide in an electrothermal furnace, we produced 350 grams per hour of high-quality nanotubes in a single furnace, compared to 200 grams per hour for the commercial process. Controlling the enthalpy prevents self-extinguishing hot gas pyrolysis. Thus, carbon dioxide enhances the properties and reduces the production cost. This is a near term advance that can go into trial production in the near term. g Seventh, economic analysis suggests an economic plan forward, producing carbon nanotubes for less than $50 per pound. The use of hydrogen and carbon dioxide as the feedstocks is acceptable from a cost basis, and in fact hydrogen is less expensive than carbon monoxide. Niche applications are available in the near term, though quantities relevant to sequestration remain a far-term goal. h. Eighth, though it was not the research team’s intention to create a new process for producing carbon monoxide, it was realized that almost by accident we demonstrated plasma reforming of carbon dioxide via a plasma version of the reverse Boudouard reaction. Accordingly, we have contacted a major gas manufacturer (Matheson Gas) to determine whether there is interest in creating an industrial version of the process. i. Ninth, a long-range strategy is identified in which a progressively more carbon-conscious world will seek to create solid carbon as a means of sequestering carbon dioxide, impeding its return to the atmosphere. In the long term the price must drop by orders of magnitude with larger production, and assuming success, solid carbon could be the preferred form for sequestration rather than underground storage. If carbon can be made as cheaply as dirt, or nearly so, then it can serve a useful purpose as structural material for housing, soil amendments in agriculture and fillers to modify low areas.

Three main categories of pollutant emissions into the atmosphere from Croatian oil and natural gas activities are: fuel combustion, fugitive and carbon dioxide separated from natural gas. The pollutants (or pollutant classes) emitted into the air are: main greenhouse gases such as CO2, CH4; indirect greenhouse gases such as NOx, CO and NMVOC gases (with no direct greenhouse effect, but they influence generation and disintegration of tropospheric and stratospheric ozon who has properties of a greenhouse gases); suspended particulate matter (SPM) and sulphur dioxide (SO2). These pollutants are emitted into the air during normal well operations, production, processing and distribution of gas and oil products. SNAP94 for CORINAIR inventory three level hierarchical emission source nomenclatures (covers 4 main sectors, 9 sub-sectors and 33 activities) has been used to characterise the cause of the emissions and to relate it to anthropogenic activity in petroleum industry. Point, line and area sources of air pollution in petroleum industry are considered. Emission estimations are based on detailed activity/technology information covering stationary sources. IPCC simplified method (Tier 1-production based average emission factor approach) for estimating CO2 non-CO2 greenhouse gases emissions, based on activity level and average emission factors, has been used. EMEP/CORINAIR detailed method (mass balance approach) to estimate fugitive emissions of ozone precursors (NOx, CO and NMVOC) from oil and natural gas activities has been also used. Comparison (in graph form) between emissions of air pollutants from INA- Petroleum Industry and emissions in Croatia has been made. Introduction Three main categories of pollutant emissions into the atmosphere from INA Croatian petroleum industry are: fuel combustion, fugitive emissions and emissions of carbon dioxide removed from natural gas. Fuel combustion result in emissions of carbon dioxide (CO2), and non-CO2 emissions such as emissions of methane (CH4), nitrous oxide (N2O), oxides of nitrogen (NOx), carbon monoxide (CO), nonmethane volatile organic compounds (NMVOC) and sulfur dioxide (SO2). Result of fugitive emissions are emissions of methane from oil and natural gas activities, emissions of ozone percursors (CO, NOx, NMVOC) and emission of SO2 from oil refining. Removal of CO2 by amine scrubbing result in subseqent emissions of CO2 into the atmosphere. The emissions of these polutants influence the air quality on local, regional and global level. Local level: Emissions of NOx, SO2, (fines) suspended particulate matter (SPM), heavy metals (HM), such as Pb, Hg, Cd, As, Ni and smoke from emission sources (stationary fuel combustion, oil refining) at petroleum refineries contribute to air quality in the urban areas where refineries are located (Rijeka, Sisak). Today, ground level concentrations of SO2 and soot at the sources at petrolum rafineries primarily due to combustion of gas instead of liquid fuel has been decreased to degree that the air quality at this urban areas belongs to first category. Regional level: Emissions from petroleum industry contribute to the problems on regional level, such as acid rains (SO2, NOx), eutrophication (NOx), high concentrations of tropospheric ozon (NOx), and pollutions with heavy metals and persistent organic pollutants (POP) such as polycyclic aromatic hydrocarbons (PAH) and dioxin. According to data, emissions of SO2, NOx from refineries (Sisak, Rijeka) contribute with 8 percent to total emissions of SO2, NOx from liquid fuels in Croatia (1).

TG-FTIR study on urea-formaldehyde resin residue during pyrolysis and combustion

Electro and photoelectrochemical reduction of carbon dioxide on multimetallic porphyrins/polyoxotungstate modified electrodes

Introduction The electrochemical conversion of CO2 has been studied for many years, and copper is the only metal catalyst found to produce hydrocarbons1. This work examines the behavior of a nanoporous copper/M electrode when used as a catalyst for the electroreduction of CO2. Materials and Methods A copper/aluminum alloy was used as the starting material for producing a high surface area copper catalyst. The aluminum was removed through an etching procedure in strong base. The resulting nanoporous copper was crushed and mixed with Nafion, a binding agent, then casted over a copper foil substrate. After drying, transition metal (M) was galvanically displaced onto the copper to form nanoporous copper/M. Carbon dioxide electroreduction was performed by placing the catalyst in a specially designed flow cell. A bubbler in the cell was used to deliver CO2 to saturate the electrolyte, 0.1 M KHCO3, at a rate of 10 mL/min. The catalyst acts as the working electrode in this electrochemical cell. The product distribution from the electroreduction process was collected at a series of potentials. Gaseous products were identified and quantified using gas chromatography coupled with both mass spectrometry and a thermal conductivity detector. Liquid products were analyzed using nuclear magnetic resonance. The surface morphology and composition of the catalyst was characterized using scanning electron microscopy (SEM) and x-ray photoelectron spectroscopy (XPS). The SEM images show a rough surface that retains a porous structure before and after experiments. Depth profiling studies with XPS show that the transition metal (M) from the surface of the material migrates to the bulk after electrolysis. Results and Discussion Identification of reduction products reveal that the catalyst is selective toward C2 species such as ethane and ethanol. This is a phenomenon that is also observed on nanoporous copper without the transition metal, while the addition of a transition metal changes the product selectivity. The only C1 species produced were carbon monoxide and formic acid, while no methane and methanol was detected. The most interesting product observed was n-propanol, a C3 species. This work provides further insight into how selectivity of the CO2 reaction can be altered by tuning the catalyst properties. The use of a nanoporous copper catalyst provides an increased surface area and introduces many step edges, which are sites that are considered to be especially electrochemically active2. The role of the transition metal has yet to be determined, however future work will focus on optimizing the selectivity as a function of controlling the Cu/M (where M = transition metals) composition in the nanoporous copper framework. References 1] Hori, Y.; Kikuchi, K.; Suzuki, S. Chem. Lett. 1985, 1695. 2] Billy, Coleman, Walz, Co, US 62/058,121. Figure 1

Catalytic gasification of mannose for hydrogen production in near- and super-critical water

Phenols production form Douglas fir catalytic pyrolysis with MgO and biomass-derived activated carbon catalysts

In this study, high-temperature catalytic pyrolysis of radiata pine was investigated for the production of high-value gas products. Pyrolysis experiments were conducted in a fluidized bed reactor at temperatures of 600 to 850 °C. The effect of temperature and the addition of titanomagnetite as the catalyst was evaluated based on product distribution, gas composition, gas properties, and tar composition. The results show that with titanomagnetite, the maximum gas yield of 72.9% was achieved at 850 °C, which is higher than that of the non-catalytic pyrolysis at the same temperature. The main gas species in the gas product from the catalytic pyrolysis at 850 °C include hydrogen (12.8 vol%), carbon monoxide (37.6 vol%), carbon dioxide (35.8 vol%), methane (5.8 vol%), and ethylene (5.8 vol%). Also, with titanomagnetite, the maximum lower heating value of 23.0 MJ/Nm3 for the product gas was achieved at 800 °C, and the maximum value for hydrogen to carbon monoxide (0.34) was found at 850 °C. Titanomagnetite promoted the formation of oxygenated hydrocarbons such as acids, esters, and phenols in tar, but at 850 °C, the tars from both catalytic and non-catalytic pyrolysis were rich in naphthalenes (more than 40%). H2-reduced titanomagnetite performed equally as the unreduced titanomagnetite with respect to gas yield, but the hydrogen and ethylene contents in the gas from the pyrolysis at 850 °C were 21.5 and 21.8 vol%, respectively. At this temperature, the lower heating value of the gas from the catalytic pyrolysis with the H2-reduced titanomagnetite was 17.4 MJ/Nm3, and the hydrogen to carbon monoxide ratio was 2.6.

Valorisation of vegetable market wastes to gas fuel via catalytic hydrothermal processing