Co-firing Method Research Articles

Preparing the In-doped lead-free Cs3Cu2I5 perovskite scintillator by a co-firing technique for its application in high-resolution X-ray imaging

The perovskite scintillators have been extensively studied recently for their merits of tunable emission spectra and simple preparation processes. However, the practical applications of perovskite scintillator-based X-ray image sensor are still impeded by inadequate radioluminescence, poor environmental stability, and low imaging resolution. Herein, we demonstrate a scalable co-firing method to fabricate high-quality lead-free Cs3Cu2I5 perovskite scintillator and an Indium (In)-doping strategy is introduced to enhance its radioluminescence performance at the same time. The In-doped Cs3Cu2I5 obtains a high PLQY of 77.9% and a relative light output of 53372 ph/MeV, which are 0.34 and 1.08 times higher than those of the undoped counterpart, respectively. The X-ray detection limit of the In:Cs3Cu2I5 can reach 150.55 nGyair/s, 36.53 times lower than the requirement for X-ray medical diagnosis. The synthesized scintillator also shows superior stability under continuous high dose X-ray irradiation of 6800 μGyair/s for 120 minutes, maintaining 95% of its initial radioluminescence intensity. Furthermore, a large-area (300 cm2) flexible perovskite scintillator film is prepared, which owns a much competitive resolution of 10 lp/mm and less distortion in X-ray imaging. This work provides a practical path for the wide application of perovskite scintillator in the field of X-ray detection and imaging in near future.

Effects of SmCo Co-substitution on the magnetic and electrical properties of low temperature sintering synthesized strontium hexaferrite

In order to mitigate the rapid grain growth, a sintered ferrite magnet exhibiting stable characteristics was successfully synthesized. M-type strontium ferrite Sr1-xSmxFe12-xCoxO19 (x = 0.00, 0.01, 0.02, 0.03, 0.04, 0.05 and 0.10) was synthesized via a low-temperature co-firing method, incorporating an appropriate quantity of Bi2O3 and CuO as additives within the solid-phase reaction process. The magnetic and electrical properties of the resulting composites were meticulously examined, and X-ray diffraction (XRD) analysis was performed for structural characterization. The findings reveal that a pure hexagonal strontium phase is achieved consistently when the substitution level, x, remains below 0.5. With an increase in the substitution level, a heterogeneous phase α-Fe2O3 becomes apparent within the phase structure. Upon introducing doping elements, the subtle incorporation of SmCo (x ≤ 0.02) enhances the saturation magnetization, remanent magnetization, and coercivity of the composite material. Moreover, the resistances of grain and grain boundary (Rg, Rgb) have been downscaled from 1.856 × 106Ω and 3.61 × 106Ω to 3.182 × 104Ω and 4.37 × 105Ω respectively. Consequently, the Sr1-xSmxFe12-xCoxO19 ferrite sintered under low-temperature conditions demonstrates outstanding electromagnetic characteristics, presenting a viable option for materials in microwave device applications.

Rational interface-enriched defects induce excellent thermoelectric performance of sandwich-type Ca3Co4O9 textured composites

Interface-enriched defects were constructed through a multilayer co-firing method, enlarging charge carrier transport channels in textured composites. At 1073 K, a maximum ZT of approximately 0.493 was achieved.

Techno Economy Evaluation of Co-firing Method with CFBB Boiler Type in Indonesia

Techno Economy Evaluation of Co-firing Method with CFBB Boiler Type in Indonesia

Rapidly Direct Laser 3D Printing of High-Performance Protonic Ceramic Fuel Cells

Fuel cells with a dense ionic conducting electrolyte layer sandwiched between two porous electrode layers are one of the most efficient fuel-to-electricity energy conversion devices. Their reversible operation can also efficiently electrolyze water to hydrogen, reduce carbon dioxide to fuels, synthesize ammonia, upgrade fuels, and store energy on large scales. Compared with the popular low-temperature (~80 oC) proton exchange/polymer electrolyte membrane fuel cells and the high-temperature (700-1000 oC) oxygen ion-conducting solid oxide fuel cells (SOFCs), initially used in electric vehicles, auxiliary powers, power plants, and hydrogen electrolyzers, the rising star of protonic ceramic fuel cells (PCFCs) based on proton conducting oxide electrolytes offers excellent suitability for operating at 400-700 oC, the optimum temperature range for electrochemical energy devices, enabling extensive superiorities (high efficiency and performance, long thermal and chemical stabilities, flexible fuels, and cost-effective compatible materials) compared to their counterparts. In recent ten years, many high-performance PCFCs have been reported. However, most performances were achieved using small-area button cells (<0.5cm2) fabricated using spin coating, drop coating, manual brushing, and screen printing of electrolytes on the dry-pressed anode supports, followed by co-firing. There are challenges to transferring the excellent microstructures and materials chemistries/properties obtained from small-area cells to large-area cells and stacks. Furthermore, the decrease in cell component layer thickness for high volumetric cell performance and the requirement for more efficient, faster, and more cost-effective manufacturing motivated the advanced manufacturing of PCFCs.This work will focus on the direct laser 3D printing (DL3DP) of PCFCs performed at Clemson University. The DL3DP integrated 3D printing (microextrusion and ultrasonic spraying) and laser processing (drying, sintering, and machining), allowing for manufacturing PCFC components, single cells, and stacks with the desired microstructures and geometries irrelevant to the area. The DL3DP could rapidly and cost-effectively manufacture PCFCs without conventional long-term furnace processing. The processing speed could be 2 orders of magnitude faster than the conventional tape-casting and furnace co-firing method. The achieved cells and stacks showed excellent fuel cell performance and less dependence on the effective area. The cells showed peak power densities 1.6-2.6 times that of the conventionally processed samples. The stacks demonstrated a peak power of 7 W and constant power outputs of 0.5-3.1 W for 110-260 hours. This DL3DP can be expanded to manufacturing other heterogeneous ceramics for energy conversion and storage devices. Figure 1

Development of Protonic Ceramic Fuel Cell Using BaZr0.2Yb0.8O3-δ as the Electrolyte

Protonic Ceramic Fuel Cells (PCFCs) are attracting attention as next-generation fuel cells that are expected to have lower operating temperatures and higher power generation efficiency than SOFCs. We have reported that BaZr0.8Yb0.2O3-δ does not chemically react with NiO used as a fuel electrode at 1475°C, which is the sintering temperature of the cell, and that the fuel cell can be fabricated by the tape casting method and the fuel electrode and electrolyte co-firing method used in industrial production processes for SOFCs and electronic components. This report describes issues that need to be resolved for the practical application of this cell.Fuel cells were fabricated by laminating green sheets prepared by the tape casting method and co-firing the electrolyte and fuel electrode together. For the air electrode, La0.6Sr0.4Co0.2Fe0.8O3-δ and La0.6Sr0.4CoO3-δ, which are widely used in SOFCs, and newly developed BaZr0.375Yb0.125Co0.5O3-δ were sintered at 900°C to 1000°C. The electrochemical performance of the planar cell was investigated at 600°C under the conditions of a humid fuel gas (i.e., 3% H2O and 97% H2) and humid air (i.e., 3% H2O, 20% O2 and 77% N2). The active area of the planar cell was 0.785 cm2.To evaluate the durability of each cell, continuous power generation tests were conducted at constant current. The durability test was conducted by generating power for 1000 hours at a constant current that resulted in a voltage of 0.85 V at the start of the test, and durability was evaluated by the rate of voltage drop per 1000 hours. As a result, the voltage reduction rate per 1000 hours for the cell using BaZr0.375Yb0.125Co0.5O3-δ as the air electrode was 7.3%/kh. The results clearly show that one of the most significant issues for practical use is the suppression of the rate of voltage drop. The resistance of the cell before and after the durability test were analyzed by electrochemical impedance method, and the ohmic resistance and electrode resistance increased. EPMA analysis of the cell cross section to investigate the cause of degradation revealed diffusion of Ni from the fuel electrode and Co from the air electrode in the electrolyte. Therefore, in order to further improve durability, there is a need to consider adding an anti-diffusion layer to prevent the diffusion of these elements and developing air electrode materials that do not contain Co.

An Anode-Supported Solid Oxide Fuel Cell (SOFC) Half-Cell Fabricated by Hybrid 3D Inkjet Printing and Laser Treatment

A NiO-10YSZ/10YSZ half-cell for anode-supported solid oxide fuel cells (SOFCs) was fabricated using 3D inkjet printing and layer-by-layer laser treatment of printing compositions followed by thermal sintering by a co-firing method. The optimal granulometric composition and rheological characteristics of the printing compositions to fabricate the NiO-10YSZ (60:40 wt.%) anode support, NiO-10YSZ (40:60 wt.%) anode functional layer (AFL), and 10YSZ electrolyte were determined. Effects of the pore former and laser post-treatment on the morphology of the as-prepared anodes for the manufacture of SOFC anode supports were studied, and the optimum laser exposure for hybrid 3D printing was determined. A mechanism of influence of the exposure of laser post-treatment on the morphology of the NiO-10YSZ anode supports has been proposed. The mass content of 10YSZ and the number of layers were shown to affect the surface microstructure and the thickness of the thin-film electrolytes deposited on the surface of the anode supports. The hybrid inkjet 3D printing offers great opportunities as it allows a one-pot procedure to fabricate a NiO-10YSZ/10YSZ SOFC half-cell for SOFC anode supports.

Economics Analysis of Coal to Biomass Subtitution: System Dynamics Approach

Biomass utilization has been promoted by Government of Indonesia to subtitute coal as source of energy for electricity production through co-firing method. Yet, the higher price of biomass compared to coal and fair puchase price of electricity from biomass hinders its subtitution. In this paper, we examine the dynamics of biomass to coal subtitution and economics factors that affect subtitution of coal to biomass. We propose integration of economic analysis and Sytem Dynamics approach to examine reasonable subsidy, electricity price and GHG emission. We find that without implementation of policy to consider coal externalities, utilisation of biomass will likely unsucessfull in implementation.

Mechanism of iron doping promoting high temperature deNOx and anti-water vapor and SO2 poisoning of ZrW(Fe)Ox

Driven by the strategy of reducing pollution and CO2, high temperature deNOx catalyst has become a major demand for current gas-fired exhaust purification. A series of Fe-doped ZrWOx complex oxides (Z1W0.2Fx) were prepared by solution evaporation and co-firing method, and effects of Fe doping on their high-temperature deNOx activity, N2 selectivity and anti-water vapor and SO2 poisoning were mainly investigated and the promotion mechanism of Fe doping was analyzed and discussed. Results showed that Fe doping significantly improved NH3-SCR of NO over the Z1W0.2Fx within 350–450 °C, mainly due to the redox properties of Fe2O3 itself. Appropriate Fe doping increased specific surface area and enhanced surface acidity of Z1W0.2Fx, the Z1W0.2F0.007 possessed the optimal catalytic performance for deNOx, with NO conversion more than 90 % and N2 selectivity more than 95 % at 400–650 °C. Moreover, compared to the blank sample of Z1W0.2, Fe doping remarkably enhanced anti-water vapor and SO2 poisoning of Z1W0.2Fx. Due to the competitive adsorption between H2O and NH3 at low temperature, water vapor has a slight influence on deNOx activity at 400 °C. Interestingly, water vapor notably improved deNOx activity and N2 selectivity at above 450 °C, because water vapor promoted the formation of hydroxyl groups and thus accelerated the Eley-Rideal deNOx at high temperature. SO2 had no influence on the deNOx performance of Z1W0.2Fx. Furthermore, both Lewis and Bronsted acid sites coexisted on the surface of Z1W0.2Fx, and the NH3-SCR of NO over Z1W0.2Fx at high temperature followed both Langmuir-Hinshelwood and Eley-Rideal reaction mechanisms.

La1-xCaxFeO3-δ air electrode fabricated by glycine-nitrate combustion method for solid oxide electrolysis cell

As a new type of energy conversion device, solid oxide electrolysis cell (SOEC) has attracted much attention in recent years because of its advantages such as high efficiency and unlimited capacity. At present, SOEC mainly has such issues as the element diffusion or delamination at oxygen electrode/electrolyte interface under high oxygen partial pressure, which limits its operation lifetime. In this paper, La1-xCaxFeO3-δ materials without Sr and Co were prepared by glycine-nitrate combustion method as SOEC oxygen electrodes. It is found that La0.6Ca0.4FeO3-δ (LCF64) has excellent electrical conductivity and has a coefficient of thermal expansion matching with SSZ electrolyte. The hydrogen electrode supported single cells with structure of LCF64-GDC (6:4) | GDC | SSZ | NiO-SSZ active layer | NiO-YSZ transition layer | NiO-YSZ supported layer were prepared by tape casting and co-firing method showed good electrochemical performance in SOEC mode. The electrolysis current density is 457.46 mA cm-2 with 60% H2O-H2 atmosphere and 1.3 V applied voltage at 800 °C. During the constant voltage (1.3V) electrolysis process, the SOEC showed an acceptable stable current density of approximate 280 mA cm-2 for more than 60 h.

A biomass-coal co-firing based bi-level optimal approach for carbon emission reduction in China

Indiscriminate carbon emissions have resulted in severe ecological problems and have highlighted the need for the coal-fired power industry to pursue sustainable development. As a carbon-neutral energy resource, biomass is regarded as a promising substitute of coal to reduce carbon emissions in power generation. For the purposes of low-carbon power generation, this paper develops a bi-level programming approach to seek an optimal biomass-coal co-firing method under a carbon emissions allowance allocation scheme, in which the local government on the upper level determines the carbon emissions allowance scheme based on economic and environmental targets as the leader, and the power plants on the lower level develop power generation plans to maximize profits under the upper-level restrictions. Different from previous papers, this optimization approach fully considers the hierarchy of multiple decision makers and environmental-economic equilibrium for global optimization. A practical case in Heilongjiang Province is presented to verify the efficiency and practicality of the proposed optimization method in carbon emissions control and biomass fuel utilization. The calculation results under various scenarios are analyzed, and the analysis indicates that power plants with lower biomass utilization are more sensitive to carbon emissions constraints. It is also found that relaxed carbon emissions constraints could encourage the utilization of biomass, but strict constraints will cause adverse effects on economic development. The management recommendations derived from this method are presented to provide valuable strategy guidance for policymakers and practitioners in future planning for co-firing power generation.

Thermal Effects of Natural Gas and Syngas Co-Firing System on Heat Treatment Process in the Preheating Furnace

Preheating furnaces, which are commonly used in many production sectors (e.g., iron and steel), are simultaneously one of the most energy-intensive devices used in the industry. Partial replacement of natural gas with biomass-derived synthesis gas as a fuel used for heating would be an important step towards limiting industrial CO2 emissions. The time dependent computational fluid dynamics (CFD) model of an exemplary furnace was created to evaluate whether it is possible to obtain 40% of energy from syngas combustion without deterioration of thermal parameters of the treated load. As an outcome, a promising method to organize co-firing in the furnace was indicated. The obtained results show that the co-firing method (up to 40% thermal natural gas replacement with syngas), assuming low air-to-fuel equivalence ratio (λNG = 2.0) and even distribution of power among the furnace corners, lead to satisfactory efficiency of the heat treatment process—the heat transferred to the load exceeds 95% of the heat delivered to the load in the reference case), while carbon dioxide emission is reduced from 285.5 to 171.3 kg CO2/h. This study showed that it is feasible (from the heat transfer point of view) to decrease the environmental impact of the process industries by the use of renewable fuels.

Study on Flow Pattern According to Rotor Design Parameter of Sewage Sludge Solid Fuel Crusher

In coal-fired power plants, approximately 5% of sewage sludge solid fuel mixed with coal is used as power generation fuel for environmental protection and global warming prevention. The co-firing method needs a sewage sludge solid fuel crusher that can crush sewage sludge solid fuel to generate a fine powder. This study aims to determine the size of the rotor perpendicular plate hole that can minimize accumulation of the crushed fuel in the roller type sewage sludge solid fuel crusher to be used in the co-firing method. The range of the design parameters for optimization of the rotor perpendicular plate hole is selected and make an orthogonal array table according to design of experiments. The CFD is performed to analyze effect of design parameters according to an orthogonal array table. In addition, the dimension of the rotor perpendicular plate hole that can minimize accumulation of the fuel inside the crusher is drawn using the Multi-objective optimization method.

A study of the influence of Li-containing additives in microtubular SOFC components based on Gd-doped ceria on the effectiveness of the co-firing method

In this work, the method of co-firing was applied to obtain NiO/GDC – GDC half-cell for MT SOFC. Microtubular anode preforms of NiO/10GDC (60/40 wt%) composition were formed using the phase-inversion technique. The paste of electrolyte material 10GDC was deposited on the anode preforms by the dip-coating method. Some amount of lithium salts (3 wt%) were added into anode material and 10GDC paste, and their effect on the formation of the gas-tight electrolytic layer was investigated. The Li-containing sintering additives were shown to increase shrinkage upon the co-firing process and allow one to lower the temperature of obtaining the gas-tight electrolytic layer by about 150 °C.

Optimization of sintering temperature for SOFCs by a co-firing method

A single-step co-firing process is employed to fabricate solid oxide fuel cells (SOFCs) with an Sm-doped CeO2 (SDC) electrolyte, aiming to simplify the SOFC fabrication procedure. Complete tri layer green cells are co-fired in a single step at different fabrication temperatures, and the co-firing temperature significantly influences the cell microstructure and thus influences its performance. Electrochemical investigations indicate that the cell resistance, including the ohmic and polarization resistance, varies with the co-firing temperatures used and leads to a different cell power output. Although the cell polarization resistance follows the rule that higher firing temperatures lead to higher polarization resistance values, the cell ohmic resistance does not follow the expectation that the cell fired at 1200 °C gives the largest ohmic resistance. The morphology analysis reveals the mechanism behind this phenomenon. The best cell performance is obtained by co-firing the cell at 1000 °C, reaching 401 mW cm−2 at 700 °C.

High Performing and Durable Anode-Supported Solid Oxide Fuel Cell by Using Tape Casting, Lamination and Co-Firing Method

This work reports development of large-area (12cm×12cm) planar anode-supported SOFC with 100cm2 active area by a tape casting, lamination and co-sintering method. The cell consists of the nickel-8mol.% yttria-stabilized zirconia as support with 0.7 mm thickness and of the nickel-scandia stabilized zirconia (ScSZ) as an anode functional layer. Processing optimization of binder/plasticizer ratio of tape casting slurry allowed to obtain the green tapes with good mechanical strength and homogenous microstructure. Casting process parameter had also a great influence on the microstructure and mechanical properties of green tapes. The anode-support showed high mechanical strength and sufficient porosity for gas transport. A 6µm thick ScSZ electrolyte and 3µm thick gadolinium-doped ceria (GDC) buffer layer were fabricated using tape casting method and co-firing process. A lanthanum strontium cobalt ferrite-GDC composite cathode was screen-printed on the GDC layer. The single cell showed a peak power density of 509mWcm-2 at 750oC.

Numerical Investigation on Co-firing Characteristics of Semi-Coke and Lean Coal in a 600 MW Supercritical Wall-Fired Boiler

Semi-coke is one of the principal by-products of coal pyrolysis and gasification, which features the disadvantages of ignition difficulty, low burnout rate, and high nitrogen oxides (NOx) emission during combustion process. Co-firing semi-coke with coal is a potential approach to achieve clean and efficient utilization of such low-volatile fuel. In this paper, the co-firing performance of semi-coke and lean coal in a 600 MW supercritical wall-fired boiler was numerically investigated which has been seldom done previously. The influences of semi-coke blending ratio, injection position of semi-coke, excess air ratio in the main combustion zone, the co-firing method, and over fire air (OFA) arrangement on the combustion efficiency and NOx generation characteristics of the utility boiler were extensively analyzed. The simulation results indicated that as the blending ratio of semi-coke increased, the NOx emission at furnace outlet decreased. The blending methods (in-furnace versus out-furnace) had certain impacts on the NOx emission and carbon content in fly ash, while the in-furnace blending method showed more flexibility in co-firing adjustment. The injection of semi-coke from the upper burners could significantly abate NOx emission at the furnace outlet, but also brought about the rise of carbon content in fly ash and the increase of outlet temperature. Compared with the condition that semi-coke and lean coal were injected from different burners, the burnout ratio of the blend premixed outside the furnace was higher at the same blending ratio of semi-coke. With the excess air ratio in the main combustion zone increased, NOx concentration at the furnace outlet was increased. The excess air ratio of 0.75 in the main combustion zone was recommended for co-firing 45% semi-coke with lean coal. The operational performance of the boiler co-firing semi-coke was greatly affected by the arrangement of OFA as well. The amount of NOx generated from the supercritical wall-fired boiler could be reduced with an increase of the OFA height.

Co-firing method of pulverized coal and ammonia for suppressing the NOx generation: Part 2

Co-firing method of pulverized coal and ammonia for suppressing the NOx generation: Part 2

Carbon emissions reductions oriented dynamic equilibrium strategy using biomass-coal co-firing

Carbon emissions are posing continuing threats to climate change and becoming the important evaluation indicator for sustainable development. The amount of global carbon emission is increasing largely, with coal-fired power plants (CPP) being the major contributor. This study proposes dynamic equilibrium strategy based on biomass-coal co-firing method to reduce carbon emissions, in which bi-level programming method is employed to build a cooperative relationship between the authority and CPPs, dynamic programming method is used to handle biomass availability time conflict, multi-objective programming method is applied to seek the trade-off between economic development and environmental protection, and furthermore uncertainty theory is introduced to address imprecise uncertain parameters. The proposed model is then applied to a case in Jiangsu, China, to demonstrate its efficiency and practicality, and an interactive algorithm is developed as the solution approach to represent the objectives and limitations between several stakeholders. Based on analyses and discussions under different scenarios, the proposed method can achieve economic-environmental coordination and realize sustainable development, and moreover a carbon emissions allocation competition mechanism is recommended. This methodology could be used in various countries and industries with only slight adjustments needed to some parameters.

Tailoring cathode composite boosts the performance of proton-conducting SOFCs fabricated by a one-step co-firing method

A strategy of tailoring the ceramic cathode composite is presented to improve the performance of proton-conducting solid oxide fuel cells (SOFCs) prepared by a one-step co-firing process. Comparing to the conventional way of using BaCe0.7Zr0.1Y0.2O3-δ (BCZY) in the composite cathode for BCZY-electrolyte based cells, the replacement of BCZY by BaZr0.8Y0.2O3-δ (BZY) mitigates the reaction between the two ceramic phases in the composite cathode during the co-firing process and also keeps the cathode with sufficient porosity for ample gas diffusion which could assist in adequate cathode reactions. As a result, the BCZY-electrolyte based cell with Sm0.5Sr0.5CoO3-δ (SSC)-BZY composite cathode shows a power output of 300 mW cm−2 at 600 °C, which is the largest ever reported for proton-conducting SOFCs prepared by a one-step co-firing process. The strategy of tailoring the composite cathode offers both small ohmic resistance and polarization resistance, providing a promising way to develop single-step co-fired proton-conducting SOFCs.