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Energy is one of the most serious problems faced by human beings in the twenty-first century. The developments of new energies have become a global consensus. With excellent electrical, mechanical, and optical properties, Graphene has important prospects of application in science, energy, biomedicine, and drug delivery, micro-nano processing. This work introduces the development of graphene and propose several mrthods for preparing graphene. It also suggests several application of graphene. Graphene is regarded as a breakthrough in the future. It is now on the eve of industrial application, and it will have a bright future when combined with new energy.

Solar energy is the most available renewable resource and has great potential for various applications. Solar heat pumps are limited when operating alone due to weather and the unstable and intermittent nature of solar energy. The idea of combining a solar collector with an air-source heat pump (ASHP) is proposed to solve the problems. Taking solar energy and air energy as the heat source of the system can improve the heat collection efficiency and heating performance coefficient of the dual-supply heating system in realizing the efficient and stable operation of the whole unit. This study investigated the application of a solar–air-source heat pump (S/AS-HP) dual-supply heating system for a residential building in Lhasa and compared the winter work performance and economic benefits of three different heating forms: solar–air-source heat pump, air-source heat pump, and solar–electric auxiliary heating systems. A simulation model was established and analyzed using the measurement data. The results show that during the heating period, the temperature of the primary side water supply is stable at about 60 °C, and the total operating hours of the solar collector period accounted for 26.9% of the total hours, of which 23.16% were independent operating hours. The average COPsys of the solar–air-source heat pump is 4.21, which greatly improves work performance compared with other systems, and the annual cost is the lowest among the three forms for the same service life at 41,824.6 CNY, saving 9.6% and 35.1% per year compared with the air-source heat pump system and the solar–electric auxiliary heating system. Considering conditions in alpine regions, S/AS-HP systems are the optimal heating solution for single buildings.

To enhance the temperature uniformity and NOx reduction performance of the gas-fired radiant tubes, we proposed a new multi-stage dispersed burner based on fuel-staging combustion technology in this study. The effect of fuel nozzle structural parameters, including secondary fuel nozzle distance D (30, 50, 70 mm), secondary fuel nozzle diameter ds (2, 3, 4, 5, 6 mm) and tertiary fuel nozzle diameter dt (2.5, 5, 7.5, 10 mm) on the flow field, temperature distribution, NOx generation and thermal efficiency were analyzed by numerical simulations. The results show that the multi-stage dispersed fuel nozzle could slow down the combustion rate and form a low-oxygen dilution zone in the reaction process, reducing the maximum combustion temperature and NOx emission. With the increase of the secondary fuel nozzle distance, the NOx concentration at the outlet decreased from 69.0 ppm to 54.6 ppm, and a decrease of 20.9%. When the secondary fuel nozzle diameter increased from 2 mm to 6 mm, the maximum wall temperature difference gradually increased 72.8 K to 76.3 K. NOx emission at the outlet first decreased, then increased, and was as low as 45.6 ppm at a 5 mm diameter. Furthermore, increasing the tertiary fuel nozzle diameter could reduce the maximum wall temperature difference and NOx emission, and improve thermal efficiency. When dt = 7.5 mm, the overall performance of the radiant tube was the best, and the outlet NOx concentration, wall temperature difference and thermal efficiency were 46.1 ppm, 73.0 K, 63.7%, respectively.

In view of its important role as raw materials in various energy and environment fields, pure oxygen has been widely required. The present cryogenic distillation, polymeric membrane and pressure swing adsorption (PSA) air separation methods are either energy-intensive or producing non-high purity oxygen. The comparative analysis of the inorganic dense ceramic-based oxygen transport membranes (OTMs) with these traditional oxygen production technologies and the H2/O2 production by electrolysis of water shows irreplaceable advantages. The oxygen transport mechanism has been elaborated further to reveal the theoretical basis for the development of OTMs. The dual-phase membranes that have been widely studied are divided into three types according to the conduction paths of oxygen ions and electrons. Based on a review of the different types of OTM materials experienced in the past 30 years, its applications such as oxygen-enriched combustion involving H2 and membrane reactors have been discussed. Finally, challenges and future directions are analyzed according to potential industrial design directions and competitive technologies of OTMs.

To solve the problem of low efficiency of NOx emission reduction in self-reflux burners, this study is based on the concept of coordinated control of self-reflux burner structural and thermal parameters. After completing the structural design and optimization of thermal parameters, we continue to adjust the two key structural parameters: the nozzle axis distance and the length of the cylindrical section, to minimize NOx emissions. These are the two parameters that chiefly affect the mixing of flue gas and fuel gas. The results show that increasing nozzle axis distance can delay the mixing of gas and air and create a more uniform oxygen concentration field for the combustion process. The maximum combustion temperature is reduced from 1973.65 K to 1935.88 K and the volume fraction of NOx in the flue gas is reduced from 188.08×10−6 to 143.47×10−6. However, compared with the nozzle axis distance, the length of the cylindrical section of the burner has little effect on the mixing of the flow field. Under different cylindrical section lengths, the maximum combustion temperature does not change more than 3 K, and the volume fraction of NOx in the flue gas changes within 5×10−6.

Spin-based logic architectures provide nonvolatile data retention, near-zero leakage, and scalability, extending the technology roadmap beyond complementary metal-oxide-semiconductor logic1-13. Architectures based on magnetic domain walls take advantage of the fast motion, high density, non-volatility and flexible design of domain walls to process and store information1,3,14-16. Such schemes, however, rely on domain-wall manipulation and clocking using an external magnetic field, which limits their implementation in dense, large-scale chips. Here we demonstrate a method for performing all-electric logic operations and cascading using domain-wall racetracks. We exploit the chiral coupling between neighbouring magnetic domains induced by the interfacial Dzyaloshinskii-Moriya interaction17-20, which promotes non-collinear spin alignment, to realize a domain-wall inverter, the essential basic building block in all implementations of Boolean logic. We then fabricate reconfigurable NAND and NOR logic gates, and perform operations with current-induced domain-wall motion. Finally, we cascade several NAND gates to build XOR and full adder gates, demonstrating electrical control of magnetic data and device interconnection in logic circuits. Our work provides a viable platform for scalable all-electric magnetic logic, paving the way for memory-in-logic applications.

Organic and inorganic phase change materials (PCMs) are considered potential materials for thermal energy storage (TES) with different phase change characteristics. In this study, a novel organic-inorganic composite phase change material (PCM) called disodium hydrogen phosphate dodecahydrate-lauric-palmitic acid (D-LA-PACM) was prepared. Expanded graphite (EG) was selected as the support material, and the novel organic-inorganic form-stable PCM called D-LA-PAPCM/EG was prepared using the vacuum adsorption method. Differential scanning calorimetry, Fourier transform infrared spectroscopy, X-ray diffraction, leakage testing, melting and solidification cycle testing, thermal conductivity testing, scanning electron microscopy observation of the micromorphology, and other characterization methods were used to study the micro structure and morphology, thermal physical parameters, thermal conductivity, stability of the PCMs, and the comprehensive material properties of D-LA-PAPCM under the composite action of EG. Results indicated that the melting and freezing temperatures and latent heats of D-LA-PAPCM/EG were measured to be 31.6°C and 34.3°C and 142.9 and 142.8 J/g, respectively. Although some of the lauric-palmitic acid (LA-PA) and disodium hydrogen phosphate dodecahydrate (DHPD) separated in the multiple porous structures of EG after 1000 cycles, they could still absorb and release latent heats independently, with D-LA-PAPCM/EG still exhibiting good thermal stability. The thermal conductivity of D-LA-PAPCM/EG was 1.361 W/(mK). Therefore, the material and thermal properties of the prepared D-LA-PAPCM/EG indicate that it could be well used as a feasible material for energy-saving phase change floor units in indoor TES systems.

In this paper, based on the structural characteristics of the double-P radiation tube, a novel type of flat double-P radiant tube was designed to improve the heating uniformity of the radiator tube and the heating efficiency of the workpiece. A new three-dimensional computational fluid dynamics modeling of the flat double-P radiant tube was conducted to discuss the heat transfer and combustion phenomenon. The influences of air and gas flow rate, air oxygen content, air consumption coefficient and air preheating temperature on flue gas circulation, surface temperature distribution and radiation power of the flat double-P radiant tube were analyzed and discussed, respectively. The amount of circulating flue gas, ratio of circulating flue gas, surface temperature non-uniformity coefficient, surface temperature distribution and radiation power of the flat double-P radiant tube with different sizes and positions of the burner nozzle characteristics were also studied in depth. The results showed that the fuel speed should be control between 40 m/s and 60 m/s. When the distance between the air nozzle and the fuel nozzle was 50 mm, or the position of the nozzles was 0 mm, the temperature non-uniformity coefficient was the lowest, which were both 0.058.

In this study, based on the structural characteristics of the traditional W-type radiation tube, a novel W-type radiant tube (N-WRT) with a flue gas circulation structure was developed to improve the heating uniformity of the radiator tube and the heating efficiency of the workpiece. New three-dimensional computational fluid dynamics modeling of the N-WRT was conducted to assess the heat transfer and combustion phenomena. In addition, the effects of nozzle diameter, nozzle location, and circulating tube diameter (all of which affect the main performance of the N-WRT) on the gas flow, temperature distribution, and nitrogen oxide (NOx) emission were analyzed and discussed in detail. Moreover, the amount of heat transfer, ratio of circulating flue gas, surface temperature distribution, thermal efficiency, and NOx concentration of the N-WRT based on different nozzle characteristics were compared. The results showed that the circulation ratio of flue gas increased from 0.47 at D60 mm to 2.2 at D28 mm. The NOx emission decreased most significantly from 100 ppm at D60 mm to 40 ppm at D50 mm. When the circulating tube diameter changed from 180 to 120 mm, the gas velocity at the junction decreased by 12%.

In this paper, an M-type radiant tube was designed first, and then based on the traditional M-type structure, a new type of radiant tube was designed with a subsonic burner and flue gas reflux channel to improve the overall performance. A three-dimensional finite element model was established, and the corresponding experimental verification was conducted to guarantee the model’s accuracy. The gas flow, heat transfer and combustion characteristics of the two types of radiant tubes were compared. The results show that the speed of the flue gas in the new type of radiant tube was about 5.55 times that of the traditional M-type radiant tube because of the self-circulating gas structure. The local high-temperature zone of the combustion flame was greatly reduced in the double-A-type radiant tube, and the gas temperature gradient was relatively small compared with the M-type radiant tube, which protected the tube surface from being burned through, and from oxidation and carburization. The gas circulation rate in the M-type radiant-tube structure was 4.42, which effectively improved the uniformity of the surface temperature and the heat flux.

The $m\phantom{\rule{0}{0ex}}e\phantom{\rule{0}{0ex}}m\phantom{\rule{0}{0ex}}o\phantom{\rule{0}{0ex}}r\phantom{\rule{0}{0ex}}y$ $w\phantom{\rule{0}{0ex}}a\phantom{\rule{0}{0ex}}l\phantom{\rule{0}{0ex}}l$, a bottleneck between storage and processor in the traditional von Neumann computing paradigm, has become increasingly serious with the rise of ``Big Data'', and there is strong interest in developing logic-in-memory computing architectures. The authors propose a skyrmion-based programmable logic device with complete Boolean logic functions, a feature that has remained elusive so far. This device can realize robust and programmable logic functions under solely electrical control, in the presence of both the inhomogeneities and thermal fluctuations that are are experimentally unavoidable. This result, then, suggests a path to overcoming the memory wall.

Magnetic skyrmions are topologically protected spin structures, offering great promise as information carriers for future spintronic devices. However, a series of challenges, such as unreliable skyrmion motion, pinning effects, and a weak readout signal, prevent the development of skyrmionic applications. The recently demonstrated capability to engineer the local exchange-bias field (LEBF) in an exchange-biased composite, provides solutions to these challenges. By exploiting LEBF, we design and analyze a robust skyrmion shift device. LEBF-induced magnetic domain walls form the boundary of the device channel, and LEBF potential wells are implemented in the channel for positioning skyrmions. Based on simulations with comprehensive models, we demonstrate the proposed device has the advantages of (i) localizing the skyrmions in the absence of current, (ii) suppressing skyrmion annihilation during transport, (iii) promoting steady skyrmion motion, (iv) enhancing the skyrmion velocity, and (v) magnifying the readout signal. Our results form the basis for the design of robust skyrmion devices through LEBF engineering.

Energy storage and transmission are important issues in the heating and cooling systems, chemical industry and other energy fields. The long-distance transmission pipeline system security under complex underground coupling loads was judged by structural deformation, especially the mechanical-fluid-thermal performance. A representative “L”-type heating pipeline system was selected as the research object and three-dimensional model was established to figure out the heat transfer, medium flowing and the deformation of the solid structure. The influence of coupled and non-coupled loads on deformation was also compared and analyzed. Results show that the deformation was affected by pressure and temperature loads simultaneously, which was lower under the coupled loads than the sum of the pressure and temperature loads alone. Due to the soil hindering the extension of the heat pipeline, the main affection factor was precisely the opposite, but the deformation distributions of the pipeline were not the exact opposite. The coupling strength was mainly influenced by pressure load under the burying laying condition, and the influence by temperature load could be ignored, whereas the coupling strength was influenced by both pressure and temperature loads under the trench laying condition.

A new type self-circulating structure for flue gas was designed, with a corresponding low-nitrogen oxides (NOx) burner developed. A three-dimensional finite element model was established, a...

Magnetic property is an important design parameter for multiferroic composites which include a magnetic component phase. In this work, it is demonstrated that the magnetic property of a ferroelectric-ferromagnetic ceramic nanocomposite film can be engineered by tuning the phase dispersion. The degree of the phase dispersion in our BaTiO3-CoFe2O4 films is evaluated by analyzing results of scanning probe microscopy, while the impact of the phase dispersion on the magnetic property is verified via alternating gradient magnetometer (AGM) measurements.

Planar Thermal Source (PTS) was used to separate ethanol from Solid-State Fermented crushed straw Material (SSFM) instead of the traditional separation method of water steam in Advanced Solid-State Fermentation technology (ASSF). Complete thermo gravimetric test was done on prepared material to study the mass change rules under heating of PTS. Factors considered were temperature of PTS (T, 20–100 °C), wet content of material (θ, 0.1–0.9), ethanol concentration in wet of material (ω, 0.03–0.11). The weight order of factors on material mass change speed V was T > θ > ω, and ω can be ignored for that was an order of magnitude less important than θ and T. V linearly increases with higher T, increases by power function with higher θ. V model with T and θ was regressed. As ethanol separating from SSFM can be considered as ethanol evaporating from ethanol solution, ethanol solution evaporation model was derived. Above all, model of ethanol separation from SSFM by PTS was derived. The cost model was added. Software was programmed to calculate the separation process and its cost. The method will promote the ASSF technology to produce fuel ethanol. The study can also be reference on drying process of other crushed plant material.

Based on the cascade utilization of high-temperature waste heat and selective non-catalytic reduction (SNCR) technology, a new-type coke oven regenerator with ammonia injection space was proposed. By changing the structure and operating parameters, the high-temperature heat storage and NO emission reduction are achieved synergistically. A three-dimensional model was used to study the flow, heat transfer, and SNCR process inside the regenerator. The validity of the model was verified. Results showed that the new-type regenerator had a significant cascade utilization characteristics of waste heat. There was a competitive reaction between NH3 + NO → N2 and NH3 → NO during the coupled SNCR process. The optimal reaction temperature window was 911 ~ 984°C, and the residence time was 0.21 ~ 0.38 s. The mixing of the reductant with the flue gas and the complete contact of NH3 with NO determined high NO reduction efficiency. Furthermore, combining multiple operating parameters, a strategy was proposed to ensure the outlet NO/NH3 concentration meets the emission standard requirements.

As a main task of national key project (2018YFC081000)“emergency power under the special environment systems research and application demonstration”, Study on Environmental Adaptability of Metal Plate Fuel Cell.the paper focus on the key technologies needed to be developed of researching PEMFC system to adapt to the special environment of high temperature, high humidity, high salt, high cold and high altitude;this topic reviews the impact of plasma exchange membrane fuel cell and climate environment on such emergency power supply equipment, and uses Au@TiN as a metal bipolar plate of proton exchange membrane fuel cell. After a series of tests, it proves the excellent operation characteristics of the fuel cell reactor in “4-high” environment.the study showed that after constant 1.0 V (vs SHE) potential polarization, the size order of different coating corrosion currents is: gold plated> stainless steel> carbonization;In a high altitude environment, the optimal air intake parameters are obtained by numerical simulation and optimization of air pressure, air volume, wind speed, air excess coefficient and other parameters;In a high-temperature environment, the problem of the metal bipolar fuel cell supply system can be solved by improving the flow structure of the air side to increase the heat exchange area and the air capacity;In the high-cold environment, the shutdown pulse sweep scheme is adopted, and the rapid start of hydrogen battery supply system is realized by using hydrogen catalytic reaction assisted heating.

The research object of this paper is “L”-type heat pipe network, which was studied using the flow–heat–solid coupling method. The ANSYS Workbench platform was used to simulate heat transfer and the flow of the medium in the pipe network. The pressure and temperature of the flow field and the temperature; and equivalent stress of the solid structure under different conditions were calculated, and the force characteristics of pipe network and elbow caused by coupled and non-coupled loads under burying and trench conditions were compared. Results show that the temperature and velocity fields of the liquid domains under burying and trench laying conditions were the same, and the structure temperature distributions of the pipe network under the two laying conditions were also the same. The pressure and temperature loads were not separate from each other, thereby affecting the stress of the pipe network simultaneously, and the stress under the coupled loads was lower than the sum of the pressure and temperature loads individually. The stress distribution of the outer and inner surfaces under burying laying condition was opposite that under trench laying condition because of the soil that hinders the extension of the heating tube.

Large-diameter buried pipelines are widely used because of their energy-saving advantage and high efficiency. In this study, an “L”-type heat pipe network was considered as research object and studied using flow–heat–solid coupling method. The ANSYS Workbench platform was used to simulate heat transfer and medium flow in the pipe network. The maximum equivalent stress and deformation of the pipe network under different displacement release conditions were calculated and compared with those under no-displacement release condition. The displacement release of the end sides did not change the stress and deformation distribution of the entire pipe network system but reduced the maximum equivalent stress and deformation, resulting in improved safety and stability of the pipeline. When the total amount of the displacement release of the inlet and outlet sections was defined, the influence of unequal end-side displacement on the stress and stress distribution of the pipe network can be neglected. Moreover, the maximum deformation gradually decreased with increasing displacement release in the inlet section and rapidly decreased with increasing total displacement release amount.

Large-diameter buried pipeline was widely used because of its energy-saving advantage and high efficiency. In this paper, “L”-type heat pipe network was taken as the research object, which was studied using the flow-heat-solid coupling method. The ANSYS Workbench platform was used to simulate heat transfer and the flow of the medium in the pipe network. The pressure and temperature of the flow field and the temperature, equivalent stress, and total deformation of the solid structure under different conditions were calculated, and the effects of different mediums on the variables of the temperature were compared. According to the theory of stress classification, stability analysis method was used to check the strength of the pipe network structure. Results show the stress and deformation of the anchorage section of the pipe network were mainly affected by the temperature of the fluid. When the pressure and temperature loads worked individually or simultaneously, maximum deformation occurred in the lateral region of the long arm near the elbow, and the maximum equivalent stress position changed according to the load change. When the medium temperatures were 60 °C and 80 °C, the strength of the pipe network structure satisfied the requirements according to the structural strength check analysis.

In this study, the nozzle characteristics of zoned and staged double P-type gas-fired radiant tube were improved to optimize combustion efficiency. A three-dimensional finite element model was established, and a grid-independence study was conducted to guarantee the accuracy of the calculation results. Corresponding experiments were designed to prove the reliability and accuracy of the simulation model. Then, the developed mode was used to determine the flow field characteristics of the zoned and staged gas-fired radiant tube. Moreover, the gas and wall temperatures were calculated by altering the gas speeds in the main and branch tube nozzles respectively. The effects of nozzle gas speed on the radiant tube were compared. Results showed that increasing the air speed of the main tube nozzle could decrease the maximum temperature and the wall temperature difference, improve temperature uniformity, and slightly increase thermal efficiency. Increasing the air speed of the branch tube nozzle could reduce the maximum wall temperature and enhance surface temperature uniformity; but these effects were relatively not significant.

Large-diameter buried pipelines are widely used because of their energy-saving advantages and high efficiency. In this paper, an “L”-type heat pipe network was taken as the research object and was studied using the flow–heat–solid coupling method. The ANSYS Workbench platform was used to simulate heat transfer and the flow of the medium in the pipe network. The pressure and temperature of the flow field and the temperature and deformation of the solid structure under different conditions were calculated. Additionally, the deformation characteristics of the pipe network under coupled and noncoupled loads were compared. Results show that the maximum deformation was located at the corner of the elbow near the long-arm region. The deformation of the inner wall was larger than that of the outer wall at the same position. The deformation of the pipe network was mainly affected by the pressure of the fluid. The deformation of the pipe network was influenced by the temperature and pressure loads coupled, and the coupling effect was stronger with the higher pressure and temperature of the medium. However, the coupling effect had limits.

In this study, the nozzle characteristics of a zoned and staged double P-type gas-fired radiant tube were improved to optimize combustion efficiency. Experimental and numerical analyses were conducted on the optimized radiant tube. The deviation between the experimental and simulated monitoring parameters was less than 3.6%, thereby proving the reliability of the model. The gas and wall temperatures were compared by changing the positions of the main and branch tube nozzles, and structural parameters. The results showed that as the nozzle moved outward, the maximum surface temperature decreased from 1328 K to 1320 K, and the minimum wall temperature increased from 1253 K to 1258 K. When the branch tube nozzle was located at the intersection of the tee and branch tubes, the impact of high-temperature gas on the tube wall was reduced, and the uniformity of the branch radial temperature was improved. When the nozzle was fully premixed, the temperature difference was at its minimum. When the tube nozzle was asymmetric, the wall temperature difference was at its minimum, and combustion thermal efficiency was at its maximum.

An electric current flowing in Pt, a material with strong spin-orbit coupling, leads to spins accumulating at the interfaces by virtue of the spin Hall effect and interfacial charge-spin conversion. We measure the influence of these interfacial magnetic moments onto adjacent $3d$ transition-metal layers by x-ray absorption spectroscopy and x-ray magnetic circular dichroism in a quantitative and element-selective way, with sensitivity below ${10}^{\ensuremath{-}5}{\ensuremath{\mu}}_{B}$ per atom. In Pt(6 nm)/Co(2.5 nm), the accumulated spins cause a deviation of the Co magnetization direction, which corresponds to an effective spin Hall angle of 0.08. The spin and orbital magnetic moments of Co are affected in equal proportion by the absorption of the spin current, showing that the transfer of orbital momentum from the recently predicted orbital Hall effect is either below our detection limit, or not directed to the $3d$ states of Co. For Pt/NM (NM = Ti, Cr, Cu), we find upper limits for the amount of injected spins corresponding to about $3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}{\ensuremath{\mu}}_{B}$ per atom.

Spin-based logic architectures provide nonvolatile data retention, near-zero leakage, and scalability, extending the technology roadmap beyond complementary metal-oxide-semiconductor logic

Although ceramic-based oxygen transport membranes (OTMs) have irreplaceable advantages over traditional oxygen production technologies, their oxygen permeability and stability need to be further improved. Based on the theoretical starting point of increasing the three-boundary reaction zone and reducing blocking effect, a set of new dual-phase membranes 75wt%Ce0.8Sm0.1Cu0.1O2-δ-25wt%-Sm0.8Sr0.2Co0.8Fe0.2O3-δ (CSC-8282) and 75wt%Ce0.8Sm0.1Cu0.1O2-δ-25wt%Sm0.3Sr0.7Co0.8Fe0.2O3-δ (CSC-3782) with different strontium contents were prepared by a one-pot sol-gel method ensuring that each element has the same chemical potential. The surface morphology, crystal structure and element distribution are systematically studied by SEM, XRD and EDS, which confirms that the synthesized membranes have an obvious dual-phase structure and excellent compactness. The results of the oxygen permeability experiment show that the oxygen permeability of CSC-3782 is always higher than that of CSC-8282 under any conditions due to the inducing effect of strontium on oxygen vacancies, and flow rate of CSC-3782 at 960°C reached 0.64 and 0.22mL⋅cm-2⋅min-1 for He and CO2 as a sweep gas, respectively. The final long-term stability test confirmed that the dual-phase composite membrane with great prospects for development has high temperature stability and CO2-tolerant property, and the doping of strontium to A-site of perovskite contributes to the improvement of its performance.

This study proposed a multi-stage dual swirl burner for heating furnaces to achieve low nitrogen oxide (NOx) emissions based on swirling combustion and staging combustion technology. The effect of excess air coefficient on combustion characteristics and NOx emissions was studied by numerical simulation. The flow field, temperature field, oxygen concentration, and the NOx concentration distributions of the burner were discussed and analysed in detail. The simulated results showed that two recirculation zones for entrained flue gas formed in the reaction process by swirl blades. Meanwhile, increasing the excess air coefficient can improve the fuel/air mixing rate and diffusion effect in the combustion chamber, reducing the maximum combustion temperature and NOx emissions. Furthermore, when the excess air coefficient increased from 1.1 to 1.4, the maximum flame temperature was reduced from 1918.3 K to 1819.6 K, and the mole fraction of NOx at the outlet decreased from 1.67×10-6 to 0.77×10-6, which revealed the potential of the burner for the clean combustion.

Based on the design concept of a fourth-generation smart pipe network system, this paper innovatively proposes a new TOTS (Two-supply/One-return, triple pipe structure) arrangement method for district heating systems. Moreover, to accurately predict the heat loss due to the pipeline operation of the multi-pipe system, based on the multipole calculation method, a new heat loss theoretical analytical model for the TOTS was created; additionally, a corresponding three-dimensional numerical simulation model was established, which was analyzed and numerically solved. The results showed that in comparison with thermal loss data measured by Danfoss et al., the above analytical and numerical models have a high accuracy, and the deviation is within 2%. Additionally, through calculations, it was found that the distance between the heating pipes is an important factor that affects the total heat loss from the new multi-control heating system and the actual heat exchange between pipes.

In this study, mass loss and direct reduction characteristics of red mud and iron ore pellets in different atmosphere and temperature was investigated. The reaction kinetics parameters were estimated based on the experiments and different model equations. In addition, the phase transformation and microstructure of the reduction process were studied by X-ray diffraction technique (XRD) and Scanning electron microscope (SEM). The results show that the reduction process is three-dimensional phase-boundary controlled in H 2 and CO atmosphere. The rate of reduction in the presence of H 2 is significantly higher than in the CO atmosphere above 900 °C. 1100 °C and hydrogen atmosphere is optimum for the reduction of both iron ore concentrate and red mud pellets in the experimental conditions.

In this study, the effects of process parameters, such as gas composition and reduction temperature, were investigated. X-ray diffraction and scanning electron microscope were used to identify the products in different atmospheres. Experimental results indicate that the three-dimensional diffusion controlled model is suited to the reduction process. The compressive strength of the produced pellets gradually decreased as the temperature increased from 700 °C to 900 °C in all atmospheres. The formation of the iron whiskers made the adjacent grains loose and eventually caused the decrease of the compressive strength. The presence of H 2 atmosphere had a strong effect on the pellets reduction due to the formation of porous and fibrous iron.

A soft-sphere discrete cohesive powder model was used to simulate the transverse mixing of particles in a rotary drum. Using this model, the effect of cohesion strength and baffle length was investigated. Mixing time (tR) and mixing entropy were used to characterize the mixing behavior. The results showed that increasing particle cohesiveness increases tR. Baffles enhanced transverse mixing, especially for high-cohesive particles. Moreover, the baffle length played a significant role on mixing. An optimized length of 0.50 (L/R) enhances transverse mixing for high-cohesive particles. Further increases in baffle length only decreases the mixing rate by impeding the surface flow layer. In contrast to high-cohesive particles, low-cohesive particles needed much shorter baffles.

According to the temperature gradient distribution characteristics of the regenerator of the coke oven, a method of synergistic the SNCR/SCR process inside the regenerator to achieve NO emission reduction was proposed in this work. Based on the verification of SNCR and SCR models, the NH3/NO concentration field and the spatial distribution characteristics of NO in the process of SNCR, SCR, and SNCR+SCR were studied. The conclusion shows that the synergistic SNCR and SCR processes had achieved NO reduction by 64.3% and 37.1%, respectively. However, the increase in reaction temperature caused by the change of injection position resulted in a 0.4% decrease in SNCR+SCR compared to SNCR. It was also found that temperature dramatically influences the SNCR process and the reductant injection position. Limited by the structure of the regenerator and the catalyst coating area, the SCR process exhibited a low NO reduction ability. The SNCR+SCR process should focus on improving the efficiency of the SCR process.

The pollution caused by sintering process in China’s iron and steel industry is especially serious. Strengthening the research on sintering process is of great significance to sustainable development. In this paper, a physical model of flue gas full-cycle sintering process is established, and the new process is simulated and calculated. The distribution of material layer temperature, flue gas temperature and flue gas composition content is obtained, and compared with the conventional sintering process from the five aspects of material layer maximum temperature, high temperature duration, material layer cooling speed, sintering time and emission reduction. The results show that the new process can increase the maximum temperature of the upper material layer, improve the uniformity of the temperature distribution in the material layer, and can enrich SO2, improve the removal efficiency of pollutants, and reduce emissions.

Based on high-temperature and low-oxygen diffusion clean combustion technology, a novel-type of heat flue in a coke oven was designed in this paper. By changing the internal structure of the flue and the supply mode of the combustion-supporting gas, fuel zoning and diffusion combustion in the heat flue are achieved. The combustion temperature in the flue and the formation of thermal NOx are greatly reduced. The flow, temperature and NOx concentration fields inside the flue are studied though a three-dimensional finite element numerical model. The results show that when coke oven gas is used as the fuel, the NOx concentration at the outlet of the diffused heat flue can be reduced to 312.89 mg/m3, which reduces the emission of nitrogen oxides by nearly 35%, compared with the result using graded heat flue. In addition, the influence of gas composition on NOx emission is also studied, and the mathematical relationship involving the gas composition (α), the maximum temperature (Tmax), and the outlet NOx concentration (CNOx) of the flue is obtained. When the preheating temperature reaches 550 K, Tave reaches 1626.76 K, and the outlet NOx concentration reaches 144.07 mg/m3, which can meet the standards for emissions and the heating requirements.