Carbon Monoxide Production Research Articles

The role of catalytic iron in enhancing volumetric sugar productivity during autothermal pyrolysis of woody biomass

Passivation of naturally occurring AAEM in biomass enhances sugar yields from the fast pyrolysis of biomass by preventing these metals from catalyzing the fragmentation of pyranose rings in cellulose and hemicellulose. However, because AAEM also catalyzes lignin depolymerization, its passivation can be accompanied by undesirable char agglomeration. Pretreatment of biomass with ferrous sulfate both passivates AAEM and substitutes ferrous ions as lignin depolymerization catalysts. This pretreatment has been particularly successful for high ash biomass like corn stover, but of limited value for low ash biomass like wood. This study explores the reasons for this discrepancy and offers a combined pretreatment of ferrous sulfate and ferrous acetate pretreatment to overcome char agglomeration in wood. This new pretreatment increased sugar yields from 4.4 wt% to 15.5 wt% and 5.4 wt% to 19.0 wt% for hardwood and softwood biomasses, respectively. This pretreatment produces an iron-rich biochar that catalyzes oxidation of the biochar under the oxygen-rich conditions of autothermal pyrolysis, which is preferentially consumed to provide the enthalpy for pyrolysis, preserving bio-oil as a more desirable energy product. Instead of producing carbon monoxide, which dominates oxidation of biochar from untreated biomass, the iron catalyzes oxidation to carbon dioxide, producing more energy per mole of oxygen consumed. In fact, oxygen demand to support autothermal pyrolysis of red oak and southern yellow pine was reduced 15% by the presence of iron in the biochar.

Real-world gaseous emission characteristics of natural gas heavy-duty sanitation trucks

As compared to conventional diesel heavy-duty vehicles, natural gas vehicles have been proved to be more eco-friendly due to their lower production of greenhouse gas and pollutant emissions, which are causing enormous adverse effects on global warming and air pollution. However, natural gas vehicles were rarely studied before, especially through on-road measurements. In this study, a portable emission measurement system (PEMS) was employed to investigate the real-world emissions of nitrogen oxides (NOx) (nitrogen monoxide (NO), nitrogen dioxide (NO2)), total hydrocarbons (THC), carbon monoxide (CO), and carbon dioxide (CO2) from two liquified natural gas (LNG) China V heavy-duty cleaning sanitation trucks with different weight. Associated with the more aggressive driving behaviors, the vehicle with lower weight exhibited higher CO2 (3%) but lower NOx (48.3%) (NO2 (78.2%) and NO (29.4%)), CO (44.8%), and THC (3.7%) emission factors. Aggressive driving behaviors were also favorable to the production of THC, especially those in the medium-speed range but significantly negative to the production of CO and NO2, especially those in the low-speed range with high engine load. In particular, the emission rate ratio of NO2/NO decreased with the increase of speed/scaled tractive power in different speed ranges.

Landfill Gas as an Alternative Energy Source

Purpose of research. With the increase of population and number of megacities, the consumption of various goods increases and the waste of which eventually turns into garbage. The growing amount of all kinds of waste every year and their negative impact on the environment is a global problem. However, with all existing methods of waste disposal, the least environmentally friendly method of waste disposal is used in our country - disposal by means of burial ground disposal at solid waste landfills. Landfills of solid waste are a source of landfill gas, the uncontrolled emissions of which have a negative impact on the environment. At the same time, the properties of landfill gas make it possible to use it as an energy source. The analysis of the problems рфму showт the relevance of the direction of using landfill gas as an alternative type of gas fuel, as well as the development of devices for its efficient combustion.Methods. The article discusses the impact of solid domestic waste (MSW) on the Earth's biosphere. The analysis of the global problem of waste disposal is carried out, solutions are considered. Based on the methodology specified in GOST 33998-2016 “Gas household appliances for cooking. General technical requirements, test methods and rational use of energy ”, we have carried out a study of the efficiency of the landfill gas combustion process in the developed design of a gas burner device equipped with a thermal splitter.Results. On the basis of experimental studies for a gas burner device of the developed design, the values of efficiency,% of the burner and the content of carbon monoxide (CO, mg / m3) in the combustion products have been obtained, depending on the length of the thermal divider.Conclusion. The results of experimental studies have shown the high efficiency of the original gas burner device when burning landfill gas.

Hindered phenolic antioxidant passivation of black phosphorus affords air stability and free radical quenching

As an antioxidant, hindered phenol scavenges free radicals. Due to the oxidative degradation of black phosphorus (BP) in the presence of water and oxygen, free radical quenching of hindered phenol antioxidants can solve this issue and improve the environmental stability and flame retardant efficiency of BP. Herein, hydroxyl-modified BP (BP-OH) with active groups on the surface was obtained by hydroxylation, and then the hindered phenol antioxidant was grafted onto the surface of BP-OH through an isophorone diisocyanate bridging covalent reaction to obtain hindered phenol-modified BP (BP-HPL). The fire hazard of thermoplastic polyurethane (TPU) can be significantly reduced by introducing BP-HPL into TPU. Adding 2 wt% BP-HPL can reduce the heat release rate and total heat release values of TPU by 49.9% and 49.0%, respectively. In addition, the reductions in smoke volume and carbon monoxide production were also significant. Compared with BP-OH, the environmental stability of BP-HPL is significantly improved. This work provides a reference for the application of BP in the field of fire safety and simultaneously achieves the improvement of the environmental stability and flame retardant performance of BP.

Effect of Improved Stoves on Wood Consumption, Particulate Matter and Carbon Monoxide Production in Central America

Biomass is the primary source of energy for cooking in rural Central America. The intensity of labour required to collect wood, levels of pollution resulting from incomplete burning, health problems linked to smoke inhalation, and pressure on forests are among the problems commonly associated with cooking with traditional stoves utilized in the region. Since the 1980s, improved stoves programs have been implemented in the region, but exogenous-developed models have had low adoption rates due to a lack of know-how for construction and repairments, expensive materials, and lack of understanding of local culinary traditions and culture. Sustainable Harvest International (SHI), a non-profit organization, has successfully developed two local improved stoves: the Damak model in Panama and the Mani model in Honduras. In both cases, anecdotal evidence of high rates of long-term adoption has been noted by SHI. Nonetheless, before this study, there has been no systematic evaluation of the efficiency of these two models in respect to 1) daily household wood consumption (kg); 2) particulate matter (PM2.5 ug/m3) concentration in the kitchen, and 3) carbon monoxide (CO ppm) concentration in the kitchen when compared to the traditional stoves used in rural households of both countries. The results presented herein were generated from a study using a random representative sample of 174 stoves and a portable Indoor Air Pollutant Meter manufactured by Aprovecho Research Center (ARC). An analysis of variance processed the data under the general and mixed model frameworks. The results showed that there was a statistically significant average decrease in wood consumption per day per stove for the improved models, as well as a statistically significant average decrease in personal exposure to particulate matter and carbon monoxide for the improved models when compared to those self-same measurements generated by traditional stoves.

Porous silver microrods by plasma vulcanization activation for enhanced electrocatalytic carbon dioxide reduction

Metal electrode is considered as an ideal candidate for electrocatalytic carbon dioxide (CO2) reduction considering its excellent chemical stability, application potential and eco-friendly properties. Optimization process such as morphological control, non-metallic doping, alloying is widely studied to improve the efficiency of metal electrodes. In this work, we successfully improved the CO2 reduction performance of silver using a facile plasma vulcanization treatment. The obtained sulfide derived silver (Ag) porous microrods (SD-AgPMRs) are optimized from both morphology and composition aspects, and demonstrates high Faradaic efficiency and partial current density for carbon monoxide (CO) production at low potentials. The larger specific surface area of porous microrod structure and the improved adsorption energy of important intermediates in comparison with Ag foil are realized by introduction of sulfur (S) atoms after plasma vulcanization activation, as suggested by density functional theory (DFT) calculations. This work presents a novel strategy to optimize metal electrocatalysts for CO2 reduction as well as to improve catalysis in other fields.

Double Active Sites in Co–Nx–C@Co Electrocatalysts for Simultaneous Production of Hydrogen and Carbon Monoxide

The hydrogen evolution reaction (HER) by electrocatalytic water splitting is a prospective and economical route. However, the approach is severely hindered by the sluggish anodic OER, poor reactivity of electrocatalysts, and low-value-added byproducts at the anode. Herein, formaldehyde was added as an anode sacrificial agent, and a bifunctional Co-Nx-C@Co catalyst containing abundant Co-N4 sites and Co nanoparticles was successfully fabricated and evaluated as both a cathodic and an anodic material for the HER and formaldehyde selective oxidation reaction (FSOR), respectively. Co-Nx-C@Co displayed a remarkable electrocatalytic performance simultaneously for both HER and FSOR with high hydrogen (H2) and carbon monoxide (CO) selectivity. Density functional theory calculations combined with experiments identified that Co-N4 and Co nanoparticles were dominating active sites for CO and H2 generation, respectively. The coupling tactic of FSOR at the anode not only expedites the reaction rate of HER but also offers a high-efficiency and energy-saving means for the generation of valuable H2/CO syngas.

Impact of Liver Transplantation on Carbon Monoxide Production as Measured by Arterial Carboxyhemoglobin Levels in Cirrhotic Patients with and without Hepatopulmonary Syndrome.

BackgroundHepatic dysfunction is associated with increased production of carbon monoxide. End-stage liver disease patients with hepatopulmonary syndrome (HPS) have been shown to have higher blood carbon monoxide levels than those without HPS. The impact of liver transplantation on blood carbon monoxide levels is currently unknown. We assessed the impact of liver transplantation on blood carbon monoxide and whether this is affected by HPS.Material/MethodsEligible liver transplant recipients had room air arterial blood gas testing performed before and after liver transplantation. The carboxyhemoglobin fraction was obtained from arterial co-oximetry and used as a surrogate for carboxyhemoglobin production. Mean arterial carboxyhemoglobin fraction before transplantation was compared to that after transplantation. Mean absolute and median relative pre- to post-transplant within-patient change in carboxyhemoglobin fraction was compared between those with and without HPS.ResultsThirty-nine transplanted cirrhotic patients were analyzed, of whom 14 (36%) met criteria for hepatopulmonary syndrome. The mean pre-transplant carboxyhemoglobin fraction was higher than the post-transplant fraction (2.6 vs 1.8, difference 0.8 [95% CI 0.4–1.2]; P value 0.0002). Of the 14 patients with HPS, 11 (79%) experienced a decrease in their carboxyhemoglobin fraction after liver transplantation; among the 25 patients without HPS, 16 (64%) experienced such a decrease (P=0.48). Neither the absolute nor relative within-patient pre- to post-transplant change in carboxyhemoglobin fraction was significantly different between patients with and without HPS.ConclusionsBlood carbon monoxide levels decreased significantly in cirrhotic patients following liver transplantation, but HPS did not affect the magnitude of this change.

Performance and Processes of Pure CO2 Electrolysis in Solid Oxide Cells

In solid oxide electrolysis cells (SOECs) carbon dioxide (CO2) is converted to carbon monoxide (CO). In the chemical industry CO is an important reactant to produce base chemicals such as acetic or formic acid or fine chemicals produced by carbonylation processes. CO is also used in the reduction of oxides to metals. Conventional processes for CO production are based on fossil resources such as coal or natural gas. CO2 electrolysis presents a sustainable method to utilize renewable energy for CO production and additionally transforms the greenhouse gas CO2 into a resource.Carbon dioxide is already used and investigated in the co-electrolysis process where it is converted alongside steam to produce syngas, a mixture of hydrogen and carbon monoxide. However, the analysis of pure CO2 electrolysis for CO production hasn’t been investigated in detail. Some studies report alternative materials or first degradation results. In this contribution the CO2 electrolysis is discussed in-depth from an electrochemical point of view. A detailed analysis by current-voltage characteristics (IV curves) and electrochemical impedance spectroscopy (EIS) was performed on commercially available cells by Elcogen consisting of a Nickel/ 8 mol % Yttrium-Stabilized Zirconia (8YSZ) cermet fuel electrode, a 8YSZ electrolyte, a Cerium Gadolinium Oxide barrier layer and a Lanthanum Strontium Cobaltite air electrode. IV curves and EIS spectra were measured at varied CO2/CO ratios, temperatures, flow rates and current densities.The results show that with increasing CO2/CO ratio the total area specific resistance (ASR) increases at open circuit voltage and decreases under load (Figure 1). A similar decrease of resistance is seen for increasing flow rates. The main resistance contribution determined from impedance analysis comes from diffusion/concentration losses[1]. The analysis by impedance spectroscopy provides information on the underlying processes and is not only of relevance for understanding pure CO2 electrolysis but also for understanding the role of CO2 reduction during co-electrolysis. Figure caption: Figure 1: ASR, |i|1.4 V and OCV for varied CO2/CO ratios at 800 °C[1]. 1Two values are given due to a hysteresis. The first value represents the forward scan and the second value represents the backward scan of the IV curve. Literature [1] S. Foit, L. Dittrich, T. Duyster, I. Vinke, R.-A. Eichel, Haart, L. G. J. de, Processes 2020, 8, 1390. Figure 1

Boundaries of High-Temperature Co-Electrolysis Towards Direct CO2-Electrolysis

High-temperature co-electrolysis of CO2 and H2O at elevated temperatures between 700 °C and 900 °C valorises CO2 to produce a mixture of carbon monoxide (CO) and hydrogen (H2), called syngas. Co-electrolysis has the great advantage over conventional processes, that the desired syngas ratios of downstream processes can be realized by varying process parameters such as temperature and feed gas composition accordingly in a one step process. Co-electrolysis can also play a vital role in counteracting power fluctuations of renewable energy sources by storing temporarily unused electricity through conversion to other energy resources like chemicals or heat for later use.The underlying processes in co-electrolysis for CO production are direct electrochemical CO2 reduction and reverse water gas shift equilibrium (RWGS). Their specific significance has not been clarified in detail yet and was controversially discussed in literature up to this day [1,2].The impact of the equilibrium partial pressure of H2O on the physical processes in the transition boundary of co-electrolysis towards direct CO2-electrolysis was investigated by AC and DC measurements for various gas compositions. The analysis led to identifying the role of the underlying electrochemical processes during co-electrolysis, in particular the electrochemical CO2 reduction compared to the conversion of CO2 in the reverse water-gas shift reaction and the electrochemical H2O reduction. The area specific resistance (ASR) was, amongst others, taken as an indicator to determine, which of the reduction reactions (H2O or CO2 reduction) is dominant depending on the gas composition. The experiments were conducted using commercially available cathode-supported full cells (Elcogen) made of Ni-8YSZ/8YSZ/CGO/LSC.Results as seen in Figure 1 show that the ASR for an equilibrium concentration of 5 % H2O is considerably larger than for higher H2O contents. Above 15 % H2O, the ASR shows no dependency on the gas composition and is comparable to pure H2O-electrolysis [3]. These observations underline the hypothesis that CO2-electrolysis becomes pre-dominant compared to H2O-electrolysis for low H2O content during co-electrolysis. With increasing H2O content, CO2-electrolysis becomes less significant and carbon dioxide is converted in the reverse water gas shift equilibrium. The origin of the discrepancy in literature was found to be the different operating H2O concentrations. A threshold has been established for the perception of CO2-electrolysis during co-electrolysis experiments.figure caption: Arrhenius plot of ASROCV for different steam concentrations at 6 l·h-1.[1] C. Stoots, J. O'Brien, J. Hartvigsen, Int. J. Hydrogen Energy 2009, 34, 4208.[2] S. D. Ebbesen, R. Knibbe, M. Mogensen, J. Electrochem. Soc. 2012, 159, F482-F489.[3] L. Dittrich, M. Nohl, E. E. Jaekel, S. Foit, L.G.J. (Bert) de Haart, R.-A. Eichel J. Electrochem. Soc. 2019, 166, F971-F975. Figure 1

Modeling of Multi-Physics Phenomena for High-Temperature Co-Electrolysis

Co-electrolysis as value chain process can contribute to various sectors like the chemical industry [1] or the energy sector [2] due to its high flexibility [3]. With its product syngas (a mixture of hydrogen (H2) and carbon monoxide (CO)), co-electrolysis acts as an upstream process to meet changing demands within the respective downstream supply chains [3]. Additionally, when 100% of renewable energy sources are used, green syngas can be produced thus coupling and connecting renewables into the existing value chains [4,5]. In order to fulfill industrial needs, the process of co-electrolysis has to be examined in detail. This work presents a 3D model of a simplified Solid Oxide Electrolysis Cell (SOEC) operating at high temperatures in the co-electrolysis mode. In this model, we evaluate the boundaries of co-electrolysis, the steam and CO2 electrolysis, as well as a detailed description of the co-electrolysis process with the help of a proposed reaction scheme. The model is fully coupled including electrochemical, chemical, heat and transport phenomena occurring at single cell level. We consider the heat of the reaction(s), accompanying reactions including possible surface reactions in co-electrolysis operation mode, Maxwell-Stefan interaction and electrochemical charge transfer reactions of the Butler-Volmer type. With calculating experimental characteristics like i-V curves (see Figure) or electrochemical impedance spectroscopy (EIS) curves, the influence of every parameter considered in each reaction step can be evaluated according to its value range. The model is in first instance validated with the pure electrolysis types. With the model, we can visualize the particle distribution within the porous cell, see the development of overpotential (see Figure) and obtain experimental characteristics which allow us to identify the contributions of each mechanism to them. This is an important step towards fundamental understanding of the co-electrolysis process on a small scale which can then be transferred to the large scale applications on stack level. Effects of degradation are envisioned to be incorporated into the model as well. Figure caption: Figure 1: Plot of the overpotential distribution at 0.6 A∙cm-2 within the porous cell electrodes with appropriate dimensions (left) and corresponding polarization curve with a current sweep from 0 to 3 A∙cm-2 in steps of 0.2 A∙cm-2 (right) both for steam electrolysis at 800°C.

Atomically Precise Dinuclear Site Active toward Electrocatalytic CO2 Reduction.

The development of atomically precise dinuclear heterogeneous catalysts is promising to achieve efficient catalytic performance and is also helpful to the atomic-level understanding on the synergy mechanism under reaction conditions. Here, we report a Ni2(dppm)2Cl3 dinuclear-cluster-derived strategy to a uniform atomically precise Ni2 site, consisting of two Ni1-N4 moieties shared with two nitrogen atoms, anchored on a N-doped carbon. By using operando synchrotron X-ray absorption spectroscopy, we identify the dynamically catalytic dinuclear Ni2 structure under electrochemical CO2 reduction reaction, revealing an oxygen-bridge adsorption on the Ni2-N6 site to form an O-Ni2-N6 structure with enhanced Ni-Ni interaction. Theoretical simulations demonstrate that the key O-Ni2-N6 structure can significantly lower the energy barrier for CO2 activation. As a result, the dinuclear Ni2 catalyst exhibits >94% Faradaic efficiency for efficient carbon monoxide production. This work provides bottom-up target synthesis approaches and evidences the identity of dinuclear sites active toward catalytic reactions.

Sustained effect of dry water in a thermal environment after fire extinguishing: Fuel surface coating methods

The elimination of heat and smoke hazards during the polymer combustion process is still challenging. In this work, we created a thermal environment using a fire propagation apparatus (FPA) and studied the sustained effect of dry water coated on the surface of polymer materials after fire extinguishing. The tests indicated an effective burnback delay and the reduction of heat and smoke hazards. This approach significantly increased the ignition time and reduced the heat release rate and the smoke and carbon monoxide production rate compared to fuel without dry water coating. The radiation intensity influenced the sustained performance of dry water, i.e., the larger the radiation intensity, the worse sustained performance. The sustained performance was also improved by using an aqueous solution as inner material. A low mass fraction of the aqueous solution yielded an improved sustained performance in the initial combustion stage. Furthermore, the gelation of dry water with the inner aqueous solution could balance the structural strength and the thermal shielding performance. These results have implications for designing a technical program toward longer escape and rescue times for stranded persons and firefighters.

Performance and Processes of Pure CO2 Electrolysis in Solid Oxide Cells

Pure carbon dioxide (CO2) electrolysis presents a sustainable method for the production of carbon monoxide (CO). CO is an important feedstock for producing base chemicals for the chemical industry. High-temperature CO2 electrolysis in solid oxide electrolysis cells (SOECs) make it possible to recycle climate-damaging CO2 and utilize renewable energy sources for the conversion to CO. We thoroughly investigated the direct CO2 electrolysis electrochemically with respect to the process parameters temperature, fuel utilization, load, flow rates, and CO2:CO feed gas ratio. With faradaic efficiencies of about 100% and high current densities of up to 1.5 A∙cm,-2 the results show the high potential of pure CO2 electrolysis.

Grafting of Alkali Metals on Fumed Silica for the Catalytic Dehydrogenation of Methanol to Formaldehyde

AbstractWater free, non‐oxidative catalytic dehydrogenation of methanol to formaldehyde is an important process for the formation of anhydrous, molecular formaldehyde (FA). Sodium or sodium‐containing salts were shown to catalyze the reaction, but their reaction mechanism remains unclear. In this work, we thus investigated the performance of a series of catalysts prepared by grafting of alkali metals on amorphous silica for methanol catalytic dehydrogenation. The resulting catalysts displayed an increased activity for the catalytic dehydrogenation of methanol. Variation of the electron density of the supported alkali metal cations severely affected the FA selectivity, which followed the trend: Li>Na>K>Rb>Cs. A large gap in selectivity towards FA between ions with a high (i. e., Li, Na) and low charge density (i. e., K, Rb, Cs) was observed. Also, increased metal loading adversely affected FA selectivity and resulted in a larger production of carbon monoxide. Sodium grafted on silica yielded the best combination of moderate conversion and high selectivity.

Complex Formation of Heme Oxygenase-2 with Heme Is Competitively Inhibited by the Cytosolic Domain of Caveolin-1.

The mechanism and physiological functions of heme oxygenase-2 (HO-2)-mediated carbon monoxide (CO) production, accompanied by heme metabolism, have been studied intensively in recent years. The enzymatic activity of constitutively expressed HO-2 must be strictly controlled in terms of the toxicity and chemical stability of CO. In this study, the molecular interaction between HO-2 and caveolin-1 and its effect on HO action were evaluated. An enzyme kinetics assay with residues 82-101 of caveolin-1, also called the caveolin scaffold domain, inhibited HO-2 activity in a competitive manner. Analytical ultracentrifugation and a hemin titration assay suggested that the inhibitory effect was generated by direct binding of caveolin-1 to aromatic residues, which were defined as components of the caveolin-binding motif in the HO-2 heme pocket. Herein, we developed a HO-2-based fluorescence bioprobe, namely EGFP-Δ19/D159H, which was capable of quantifying heme binding by HO-2 as the initial step in the CO production. The fluorescence of EGFP-Δ19/D159H decreased in accordance with 5-aminolevulinic acid-facilitated heme biosynthesis in COS-7 cells. In contrast, expression of the N-terminal cytosolic domain of caveolin-1 (residues 1-101) increased the probe fluorescence, suggesting that the cytosolic domain of caveolin-1 potently inhibits the binding of heme to the heme pocket of EGFP-Δ19/D159H. Taken together, our results suggest that caveolin-1 is a negative regulator of HO-2 enzymatic action. Moreover, our bioprobe EGFP-Δ19/D159H represents a powerful tool for use in future studies addressing HO-2-mediated CO production.

Efficient Redox-Neutral Photocatalytic Formate to Carbon Monoxide Conversion Enabled by Long-Range Hot Electron Transfer from Mn-Doped Quantum Dots.

Energetic hot electrons generated in Mn-doped quantum dots (QDs) via exciton-to-hot-electron upconversion possess long-range transfer capability. The long-range hot electron transfer allowed for superior efficiency in various photocatalytic reduction reactions compared to conventional QDs, which solely rely on the transfer of band edge electrons. Here we show that the synergistic action of the interfacial hole transfer to the initial reactant and subsequent long-range hot electron transfer to an intermediate species enables highly efficient redox-neutral photocatalytic reactions, thereby extending the benefits of Mn-doped QDs beyond reduction reactions. The photocatalytic conversion of formate (HCOO-) to carbon monoxide (CO), which is an important route to obtain a key component of syngas from an abundant source, is an exemplary redox-neutral reaction that exhibits a drastic enhancement of catalytic efficiency by Mn-doped QDs. Mn-doped QDs increased the formate to CO conversion rate by 2 orders of magnitude compared to conventional QDs with high selectivity. Spectroscopic study of charge transfer processes and the computational study of reaction intermediates revealed the critical role of long-range hot electron transfer to an intermediate species lacking binding affinity to the QD surface for efficient CO production. Specifically, we find that the formate radical (HCOO)•, formed after the initial hole transfer from the QD to HCOO-, undergoes isomerization to the (HOCO)• radical that subsequently is reduced to yield CO and OH-. Long-range hot electron transfer is particularly effective for reducing the nonbinding (HOCO)• radical, resulting in the large enhancement of CO production by overcoming the limitation of interfacial electron transfer.

Production of carbon monoxide from a He/CO2 plasma jet as a new strategy for therapeutic applications

AbstractA new method to deliver carbon monoxide (CO) for medical applications is presented using a kHz‐driven helium plasma jet with a 1% CO2 admixture. Despite being known for its anti‐inflammatory, vasorelaxing, and anti‐apoptotic effects, a possible role of CO generated from plasma for the treatment of various diseases has so far been neglected. Here, we show that CO production of a plasma jet can be tuned from 100 to 2000 ppm. The number of CO molecules produced per pulse is in the range of 1 × 1012 to 1.5 × 1013. To assess the delivery of CO, mouse blood hemoglobin was used as a scavenger of CO and the consequent formation of carboxyhemoglobin was quantified. This study reveals for the first time that plasma can generate and deliver CO for therapeutic interventions.

Investigation of an Intensified Thermo-Chemical Experimental Set-Up for Hydrogen Production from Biomass: Gasification Process Performance—Part I

Biomass gasification for energy purposes has several advantages, such as the mitigation of global warming and national energy independency. In the present work, the data from an innovative and intensified steam/oxygen biomass gasification process, integrating a gas filtration step directly inside the reactor, are presented. The produced gas at the outlet of the 1 MWth gasification pilot plant was analysed in terms of its main gaseous products (hydrogen, carbon monoxide, carbon dioxide, and methane) and contaminants. Experimental test sets were carried out at 0.25–0.28 Equivalence Ratio (ER), 0.4–0.5 Steam/Biomass (S/B), and 780–850 °C gasification temperature. Almond shells were selected as biomass feedstock and supplied to the reactor at approximately 120 and 150 kgdry/h. Based on the collected data, the in-vessel filtration system showed a dust removal efficiency higher than 99%-wt. A gas yield of 1.2 Nm3dry/kgdaf and a producer gas with a dry composition of 27–33%v H2, 23–29%v CO, 31–36%v CO2, 9–11%v CH4, and light hydrocarbons lower than 1%v were also observed. Correspondingly, a Low Heating Value (LHV) of 10.3–10.9 MJ/Nm3dry and a cold gas efficiency (CGE) up to 75% were estimated. Overall, the collected data allowed for the assessment of the preliminary performances of the intensified gasification process and provided the data to validate a simulative model developed through Aspen Plus software.

Hydrogen Generation from Wood Chip and Biochar by Combined Continuous Pyrolysis and Hydrothermal Gasification

Hydrothermal gasification (HTG) experiments were carried out to extract hydrogen from biomass. Although extensive research has been conducted on hydrogen production with HTG, limited research exists on the use of biochar as a raw material. In this study, woodland residues (wood chip) and biochar from wood-chip pyrolysis were used in HTG treatment to generate hydrogen. This research investigated the effect of temperature (300–425 °C) and biomass/water (0.5–10) ratio on gas composition. A higher temperature promoted hydrogen production because the water–gas shift reaction and steam-reforming reaction were promoted with an increase in temperature. The methane concentration was related positively to temperature because of the methanation and hydrogenation reactions. A lower biomass/water ratio promoted hydrogen production but suppressed carbon-monoxide production. Most reactions that produce hydrogen consume water, but water also affects the water–gas shift reaction balance, which decreases the carbon-monoxide concentration. By focusing on the practical application of HTG, we attempted biochar treatment by pyrolysis (temperature of heating part: 700 °C), and syngas was obtained from hydrothermal treatment above 425 °C.