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"Synthesis gas."
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A Modified Two-Step Coprecipitation Method Provides Better CuZnO/Al2O3 Methanol Synthesis Catalyst with More Uniform Distribution of Alumina
A modified two-step coprecipitation method has been formulated to prepare a series of model CuZnO/Al
2
O
3
catalysts for methanol synthesis from syngas. Evaluation at industrially relevant condition showed slightly higher activity and much higher stability for model catalysts than for a commercial catalyst. Due to the same CuZn-binary precursor, the model catalysts had similar structural properties with large specific surface area and pore volume, small CuO crystallites and good reducibility, resembling that of the commercial catalyst. However, the model catalysts showed much better uniformity of alumina distribution, which accounted for their better performance. Strong positive correlation between the deactivation rate and the coefficient of variation of Al/Zn indicates the uniformity of alumina distribution plays an important role in determining stability. Specifically, CuZnO/Al
2
O
3
catalysts with alumina distributed more uniformly had higher stability. This work demonstrated that the formulated modified two-step coprecipitation could provide excellent CuZnO/Al
2
O
3
catalysts for industrial applications. Additionally, it also affords new clues for the development of even better industrial catalysts.
Graphical Abstract
Journal Article
Study on the minimum extinguishing concentration of C6F12O for extinguishing synthesis gas flame of lithium-ion battery
Accidents involving lithium-ion batteries in electric vehicles frequently occur, which limits the industry's growth and makes it more challenging to build the energy supply sustainably. In this study, we add a liquid-phase input end to make cup burner suitable for the fire-extinguishing test of liquid-phase fire-extinguishing agent and test the minimum extinguishing concentration (MEC) of C
6
F
12
O on the synthesis gas of lithium-ion battery. Furthermore, the physical effects and chemical effects of C
6
F
12
O on lithium-ion battery syngas fire are quantified by the perfect stirred reactor (PSR) model. The result shows that the fire-extinguishing effect of C
6
F
12
O on lithium-ion battery fire mainly depends on the physical effect of cooling.
Journal Article
Highly Stable Photocatalytic Dry and Bi-Reforming of Methane with the Role of a Hole Scavenger for Syngas Production over a Defective Co-Doped g-C3N4 Nanotexture
Photocatalytic reduction of CO2 with CH4 through the dry reforming of methane (DRM) is an attractive approach to recycling greenhouse gases into valuable chemicals and fuels; however, this process is quite challenging. Although there is growing interest in designing efficient photocatalysts, they are less stable, and have lower photoactivity when employed for DRM reactions. Herein, we developed a noble metal-free hierarchical graphitic carbon nitride (HC3N4) loaded with cobalt (Co) for highly efficient and stable photocatalytic dry reforming of methane to produce synthesis gases (CO and H2). The performance of the newly designed Co/HC3N4 composite was tested for different reforming systems such as the dry reforming of methane, bi-reforming of methane (BRM) and reforming of CO2 with methanol–water. The performance of HC3N4 was much higher compared to bulk g-C3N4, whereas Co/HC3N4 was found to be promising for higher charge carrier separation and visible light absorption. The yield of CO and H2 with HC3N4 was 1.85- and 1.81-fold higher than when using g-C3N4 due to higher charge carrier separation. The optimized 2% Co/HC3N4 produces CO and H2 at an evolution rate of 555 and 41.2 µmol g−1 h−1, which was 18.28- and 1.74-fold more than using HC3N4 during photocatalytic dry reforming of methane (DRM), with a CH4/CO2 feed ratio of 1.0. This significantly enhanced photocatalytic CO and H2 evolution during DRM was due to efficient charge carrier separation in the presence of Co. The CH4/CO2 feed ratio was further investigated, and a 2:1 ratio was best for CO production. In contrast, the highest H2 was produced with a 1:1 feed ratio due to the competitive adsorption of the reactants over the catalyst surface. The performance of the composite was further investigated for bi-reforming methane and methanol. Using photocatalytic CO2 reduction with CH4/H2O, the production of CO and H2 was reduced, whereas significantly higher CO and H2 evolved using the BRM process involving methanol. Using methanol with CO2 and H2O, 10.77- and 1.39-fold more H2 and CO efficiency was achieved than when using dry reforming of methane. The composite was also very stable for continuous synthesis gas production during DRM in consecutive cycles. Thus, a co-assisted g-C3N4 nanotexture is promising for promoting photocatalytic activity and can be further explored in other solar energy applications.
Journal Article
Small-Scaled Production of Blue Hydrogen with Reduced Carbon Footprint
This article reviews a method of hydrogen production based on partial non-catalytic oxidation of natural gas in an original synthesis gas generator. The working principles of the unit are similar to those of liquid-propellant rocket engines. This paper presents a description of the operation and technical characteristics of the synthesis gas generator. Its application in the creation of small-scaled plants with a capacity of up to 5–7 thousand m3/h of hydrogen is justified. Hydrogen production in the developed installation requires a two-stage method and includes a technological unit for producing a hydrogen-containing gas. Typical balance compositions of hydrogen-containing gas at the synthesis gas generator’s outlet are given. To increase the hydrogen concentration, it is proposed to carry out a two-stage steam catalytic conversion of carbon monoxide contained in the hydrogen-containing gas at the synthesis gas generator’s outlet using a single Cu–Zn–cement-containing composition. Based on thermodynamic calculations, quasi-optimal modes of natural gas partial oxidation with oxygen are formulated and the results of material balance calculation for the installation are presented. In order to produce “blue” hydrogen, the scheme of carbon dioxide separation and liquefaction is developed. The conclusion section of the paper contains the test results of a pilot demonstration unit and the recommendations for improving the technology and preventing soot formation.
Journal Article
The Effect of Composition of Synthesis Gas on the Parameters of Supercharged Combustion Engine
Synthesis gases produced from municipal waste or plastic waste pose a great alternative source of energy, as they are not only reducing dependency on the fossil fuels, but also diversify energy sector and reduce the amount of a landfilled waste. This is directly related to the recent initiatives and legislation related to the greening of transport. The presented contribution focuses on the influence of six selected synthesis gases on the internal parameters of an internal combustion engine intended for cogeneration. The investigated gases fall into the category of medium-energy gases (8 – 14 MJ.kg−1). The experimental measurements have shown that mainly the proportion of hydrogen in the mixture has an effect on shortening the burning time and also on the maximum rate of pressure increase. A higher proportion of CO and H2 increased the maximum combustion pressure with slightly reduced power. The concentration of CH4 directly affected the volumetric value of the heating value of the mixture with a subsequent direct effect on the IMEP or engine torque. The engine operating at full load at speed of 1500 min−1, when running on the selected mixtures in comparison with the operation on natural gas, decreased its engine torque in the range between 13 and 20% and increased its hourly fuel consumption from 2.31 kg.h−1 for natural gas to the span of 7.90 - 12.30 kg.h−1 for measured gases. During the measurement of the control characteristic all investigated synthesis gases have developed an abnormal (detonation) combustion near the optimum pre-ignition angle.
Journal Article
Dry reforming of methane to syngas: a potential alternative process for value added chemicals—a techno-economic perspective
During the past decade, there has been increasing global concern over the rise of anthropogenic CO
2
emission into the Earth’s atmosphere (J Air Waste Manage Assoc 53:645–715, 2003). The utilization of CO
2
to produce any valuable product is need of the hour. The production of syngas from CO
2
and CH
4
seems to be one of the promising alternatives in terms of industrial utilization, as it offers several advantages: (a) mitigation of CO
2
, (b) transformation of natural gas and CO
2
into valuable syngas, and (c) producing syngas with H
2
/CO ratio 1 which may further be used for the production of valuable petrochemicals (J Air Waste Manage Assoc 53:645–715, 2003). A conceptual design for the production of synthesis gas by dry reforming of methane is presented here. An economic assessment of this process with an integrated methanol production section as a case was conceptualized and compared with the conventional steam methane reforming route to produce methanol. The economic study indicated that dry reforming of natural gas/methane is a competitive process with lower operating and capital costs in comparison with steam reforming assuming negligible cost of CO
2
import.
Journal Article
Sorption-Enhanced Water-Gas Shift Reaction for Synthesis Gas Production from Pure CO: Investigation of Sorption Parameters and Reactor Configurations
A sorption-enhanced water-gas shift (SEWGS) system providing CO2-free synthesis gas (CO + H2) for jet fuel production from pure CO was studied. The water-gas shift (WGS) reaction was catalyzed by a commercial Cu/ZnO/Al2O3 catalyst and carried out with in-situ CO2 removal on a 20 wt% potassium-promoted hydrotalcite-derived sorbent. Catalyst activity was investigated in a fixed bed tubular reactor. Different sorbent materials and treatments were characterized by CO2 chemisorption among other analysis methods to choose a suitable sorbent. Cyclic breakthrough tests in an isothermal packed bed microchannel reactor (PBMR) were performed at significantly lower modified residence times than those reported in literature. A parameter study gave an insight into the effect of pressure, adsorption feed composition, desorption conditions, as well as reactor configuration on breakthrough delay and adsorbed amount of CO2. Special attention was paid to the steam content. The significance of water during adsorption as well as desorption confirmed the existence of different adsorption sites. Various reactor packing concepts showed that the interaction of relatively fast reaction and relatively slow adsorption kinetics plays a key role in the SEWGS process design at low residence time conditions.
Journal Article
Clean Forest—Project Concept and Early Results
The Clean Forest project aims to valorize forest biomass wastes (and then prevent their occurrence as a fuel source in forests), converting it to bioenergy, such as the production of 2nd generation synthetic biofuels, like bio-methanol, bio-DME, and biogas, depending on the process operating conditions. Valorization of potential forest waste biomass thus enhances the reduction of the probability of occurrence of forest fires and, therefore, presents a major value for local rural communities. The proposed process is easy to implement, and energetically, it shows significantly reduced costs than the conventional process of gasification. Additionally, the input of energy necessary to promote electrolysis can be achieved with solar energy, using photovoltaic panels. This paper refers to the actual progress of the project, as well as the further steps which consist of a set of measures aimed at the minimization of the occurrence of forest fires by the valorization of forest wastes into energy sources.
Journal Article