Ultra-low Emission Research Articles

Reductions of multiple air pollutants from coking industry through technology improvements and their impacts on air quality and health risks in a highly industrialized region of China

The Beijing-Tianjin-Hebei (BTH) region, a highly industrialized area in China, boasts a concentration of coking plants that constitute a vital component of the steel industry. In recent years, the Chinese government has implemented measures including backward production capacity elimination (BPCE), ultra-low emission technology transformation (ULET), and deep treatment of volatile organic compounds (DTV), to promote technological progress in the coking industry and mitigate the impact of pollutant emissions. This study focuses on the emission trends, reduction effects of various measures, and the impact on air quality and human health in the regional scale. The findings reveal that in 2015, the emissions of PM, SO2, NOx and VOCs of the coking industry in BTH region were 29.15, 9.64, 26.62 and 82.99 Gg (1000 tons/year) respectively. However, by 2019, these emissions had significantly decreased by 19.95, 5.78, 18.69, and 22.53 Gg, respectively. Of these reductions, ULET contributed about 80.3 % of NOx and SO2, and 57.4 % of PM. Meanwhile, DTV and BPCE contributed 49.2 % and 50.7 % of VOCs emission reduction, respectively. Despite the improvement effect on PM2.5, SO2, and NO2 is limited, the substantial decrease in VOCs (particularly benzene) resulted in a significant reduction in the coking industry's contribution to the atmospheric benzene concentration, dropping from 15.9 % in 2015 to 11.6 % in 2019. Moreover, the lifetime cancer risk (LCR) contribution of benzene inhalation in the BTH region also decreased from 1.7 × 10−6 to 1.2 × 10−6. Looking ahead to 2025, the continued implementation of DTV will be expected to reduce VOCs emissions by 24.41Gg. This will bring the industry's contribution to the benzene concentration down to 6.8 % and the cancer risk of the population to an acceptable level (LCR < 1 × 10−6). Additionally, the deep treatment of VOCs in coking plants will significantly reduce the health risks faced by people living in the vicinity of the plants.

Investigating the impact of London’s ultra low emission zone on children’s health: children’s health in London and Luton (CHILL) protocol for a prospective parallel cohort study

BackgroundAir pollution harms health across the life course. Children are at particular risk of adverse effects during development, which may impact on health in later life. Interventions that improve air quality are urgently needed both to improve public health now, and prevent longer-term increased vulnerability to chronic disease. Low Emission Zones are a public health policy intervention aimed at reducing traffic-derived contributions to urban air pollution, but evidence that they deliver health benefits is lacking. We describe a natural experiment study (CHILL: Children’s Health in London and Luton) to evaluate the impacts of the introduction of London’s Ultra Low Emission Zone (ULEZ) on children’s health.MethodsCHILL is a prospective two-arm parallel longitudinal cohort study recruiting children at age 6–9 years from primary schools in Central London (the focus of the first phase of the ULEZ) and Luton (a comparator site), with the primary outcome being the impact of changes in annual air pollutant exposures (nitrogen oxides [NOx], nitrogen dioxide [NO2], particulate matter with a diameter of less than 2.5micrograms [PM2.5], and less than 10 micrograms [PM10]) across the two sites on lung function growth, measured as post-bronchodilator forced expiratory volume in one second (FEV1) over five years. Secondary outcomes include physical activity, cognitive development, mental health, quality of life, health inequalities, and a range of respiratory and health economic data.DiscussionCHILL’s prospective parallel cohort design will enable robust conclusions to be drawn on the effectiveness of the ULEZ at improving air quality and delivering improvements in children’s respiratory health. With increasing proportions of the world’s population now living in large urban areas exceeding World Health Organisation air pollution limit guidelines, our study findings will have important implications for the design and implementation of Low Emission and Clean Air Zones in the UK, and worldwide.ClinicalTrials.govNCT04695093 (05/01/2021).

Investigation of the NO removal process of ultra-low temperature adsorption-rapid regeneration

NO removal facility installed at the very tail-end of the flue gas could reduce the effects of dust and SO2 poisoning, the problem is to figure out how to remove NOx at ultra-low temperature. Relying on rotary reactors, a NOx adsorption-enclosed regeneration process (NAER) was proposed, by which NOx is adsorbed onto the adsorbent at ambient temperature and then to on-site degrade in a high-temperature and enclosed environment with the high-concentration CO. Metal-doped activated carbon emerged as the optimal catalyst for shortening the cooling temperature difference. The results indicated that the maximum adsorption capacity for NO is 38.67 mg/g at 50 ℃, and NO conversion reaches exceed 90 % at 250 ℃ when 1400 ppm CO and 700 ppm NO are introduced into the reactor. The novel enclosed high-concentration of CO reduction regeneration encourages more NO to participate in the reaction, promoting the deep decomposition of nitrate and avoiding the overflow of NOx at the outlet. The difference between the breakthrough time and regeneration time spans 12–21 min. The carbon consumption is 0.0087 %/min, ensuring the long-term and continuous operation of the material. The current study explains the reaction mechanism of NO adsorption via in-situ FTIR. Life cycle assessment method is applied to analyze NAER’s emission standards, while life cycle inventory method calculates the economic cost, which stands at 287.06 RMB. The reduced cost is primarily reflected in the energy and raw materials inputs. The proposed process holds significant potential for optimizing the ultra-low emission of flue gas.

Transient and altitude performance analysis of hydrogen fuelled internal combustion engines with different charging concepts

In the internal combustion engine industry, there is a significant shift towards alternative fuels to accomplish zero net carbon dioxide emissions as well as the legislation requirements. According to former studies, in addition to its advantages of being carbon-free and having appropriate combustion characteristics, low nitrogen oxide engine-out emission levels are achieved at lean burn combustion of hydrogen. Lean combustion leads to a turbocharging system requirement. Which is then utilized to generate the expected power output at high altitudes and during transient maneuvers.This study aims to determine the ideal air-charging vessel which can meet the objectives of high altitude. Which is 0 % torque derate and transient response time with respect to 0 %–90 % of maximum torque which is typically ∼3–4 s for diesel engines, while keeping the lean combustion to release ultra-low NOX emissions. Different charging concepts have been investigated by applying 1-D thermodynamic modeling on a H2ICE with a direct injection system which is for heavy-duty vehicles.

Comparing and optimizing municipal solid waste (MSW) management focused on air pollution reduction from MSW incineration in China

China is the largest developing country in the world, and its municipal solid waste (MSW) has increased with a compound annual growth rate of 5.1 % since 1980. Incineration, which has the advantages of mass- and volume-reduction as well as energy and heat recovery, has become the mainstream environmentally sound treatment method in China. However, air pollution emissions are the primary reason for limiting MSW incineration (MSWI). Currently, the Chinese government is devoted to comprehensively implementing MSW classification. However, the classification model and the future MSW reduction rate are not yet clear. In this study, we project scenarios of air pollution emissions until 2030 based on the different MSW classification models (MSW reduction rates) and diffusion rates of ultra-low emission technology. A total of 6011 tons (t) of particulate matter, 25,881 t of SO2, 14,915 t of CO, 17,167 t of HCl, and 200,166 t of NOx will be emitted in 2030 under the business-as-usual (BAU) scenario, and air pollutants will not peak under this scenario. Air pollutants will reduce by 11 % of the BAU scenario by only implementing an MSW reduction of 20 % (JPN-model). The optimal scenario (DEU-model, increasing the efficiency of material recovery and upgrading air pollution control devices) means that air pollutants will be reduced by 83.2–96.2 % from the base amount under the BAU scenario. These results provide references for MSW management and air pollution emission reduction from the aspects of MSW classification and technology upgrades in China.

Achieving health-oriented air pollution control requires integrating unequal toxicities of industrial particles

Protecting human health from fine particulate matter (PM) pollution is the ambitious goal of clean air actions, but current control strategies largely ignore the role of source-specific PM toxicity. Here, we proposed health-oriented control strategies by integrating the unequal toxic potencies of the most polluting industrial PMs. Iron and steel industry (ISI)-emitted PM2.5 exhibit about one order of magnitude higher toxic potency than those of cement and power industries. Compared with the current mass-based control strategy (prioritizing implementation of ultralow emission standards in the power sector), the proposed health-oriented control strategy (priority control of the ISI sector) could generate 5.4 times higher reduction in population-weighted toxic potency-adjusted PM2.5 exposure among polluting industries in China. Furthermore, the marginal abatement cost per unit of toxic potency-adjusted mass of ISI-emitted PM2.5 is only a quarter of that of the other two sectors under ultralow emission scenarios. We highlight that a health-oriented air pollution control strategy is urgently required to achieve cost-effective reductions in particulate exposure risks.

Sustainability of hydrogen-enriched methane MILD combustion over a wide range of hydrogen-blending ratios in a strongly heat-extracted well-stirred reactor

Moderate or intense low-oxygen dilution (MILD) combustion of methane blended with hydrogen offers a potential solution for gas-fired industrial furnaces and even boilers to realize rapid decarbonization while maintaining ultra-low NO emissions. In this work, the combustion mode map for identifying MILD combustion when burning CH4/H2 mixtures from pure methane to pure hydrogen is proposed, and then the sustainability of hydrogen-enriched methane MILD combustion over a wide range of hydrogen-blending ratios from 0 to 100% under strongly heat-extracted conditions is revealed. Results show that, there exists a threshold oxygen mole fraction (XO2*) below which hydrogen-enriched methane MILD combustion can be achieved as long as the inlet temperature (Tin) is above the self-ignition temperature of reactants. As the hydrogen-blending ratio increases from 0 to 100%, XO2* is reduced from 9.3 to 6.5% and thus the unconditional MILD combustion region is concentrated, implying that hydrogen addition requires a larger oxygen dilution level to sustain MILD combustion. Interestingly, the sustainable operating range of oxygen concentration to sustain hydrogen-enriched methane MILD combustion can be extended by increasing the heat extraction ratio (HER) properly, e.g., XO2* up to 13.2% at HER = 30% for pure hydrogen fuel. However, methane MILD combustion would become unstable and even extinguished once HER exceeds about 49%, whereas MILD combustion of methane blended with a high percentage of hydrogen could be sustained even under highly heat-extracted conditions, e.g., a maximum allowable HER of about 91% for pure hydrogen fuel. In pure hydrogen MILD combustion, heat extraction can further reduce NO emissions, mainly due to less NO production via the N2O-intermediate, NNH, and thermal pathways, and NO reduction by H radicals tends to be weakened with heat extraction. In conclusion, high-percentage hydrogen co-firing makes it possible to achieve stable MILD operation with low NO emissions under strongly heat-extracted conditions encountered in boilers.

Study on Multi-Pollutant Test and Performance Index Determination of Wet Electrostatic Precipitator

A wet electrostatic precipitator (WESP) is typically installed downstream of wet flue gas desulfurization (WFGD) to remove fine particles and sulfuric acid mists from flue gases in coal-fired power plants. The emission reduction characteristics of multiple pollutants and the energy consumption data of 214 sets of WESPs (94 sets of metal plate WESPs, 111 sets of conductive Fiber Reinforced Plastic WESPs, and 9 sets of flexible plate WESPs) were tested and analyzed, and the results showed that: WESPs had a high removal efficiency on PM, PM2.5, SO3, droplets and Hg, and mostly concentrated in ≥75%, ≥70%, ≥60%, ≥70% and ≥40%, respectively. The outlet pollutant concentrations were mostly concentrated in ≤5 mg/m3, ≤3 mg/m3, ≤5 mg/m3, ≤15 mg/m3 and ≤5 μg/m3, respectively. Specific power consumption and specific water consumption were concentrated in the range of 0.5~2.5 × 10−4 kWh/m3 and ≤10 × 10−6 t/m3. The correlation analysis of multiple pollutant’s removal performance was studied and the quantitative evaluation index requirements of high efficiency WESPs were determined in this paper. The high efficiency indexes of WESPs, such as PM emission concentration, SO3 emission concentration, PM removal efficiency, SO3 removal efficiency, pressure drop, air leakage rate and specific power consumption, were ≤2.50 mg/m3, ≤2.50 mg/m3, ≥90%, ≥85%, ≤200 Pa, ≤0.5% and ≤1.3 × 10−4 kWh/m3, respectively. The high efficiency indexes of specific water consumption for metal plate WESPs and FRP WESPs were ≤2.50 and ≤0.66 × 10−6 t/m3, respectively. This study can provide valuable reference for the following energy conservation and efficiency improvement of ultra-low emission units.

CPFD modeling of hydrodynamics, combustion and NOx emissions in an industrial CFB boiler

The ultra-low NOx emission requirement (50 mg/m3) brings great challenge to CFB boilers in China. To further tap the NOx abatement potential, full understanding the fundamentals behind CFB boilers is needed. To achieve this, a comprehensive CPFD model is established and verified; gas-solid flow, combustion, and NOx emission behavior in an industrial CFB boiler are elaborated; influences of primary air volume and coal particle size on furnace performance are evaluated. Simulation results indicate that there exists a typical core-annular flow structure in the boiler furnace. Furnace temperature is highest in the bottom dense-phase zone (about 950 °C) and decreases gradually along the furnace height. Oxygen-deficient combustion results in high CO concentration and strong reducing atmosphere in the lower furnace. NOx concentration gradually increases in the bottom furnace, reaches maximum at the elevation of secondary air inlet, and then decreases slightly in the upper furnace. Appropriate decreasing the primary air volume and coal particle size would increase the CO concentration and intensify the in-furnace reducing atmosphere, which favors for NOx reduction and low NOx emission from CFB boilers.

Multi-condition operational optimization with adaptive knowledge transfer for municipal solid waste incineration process

To satisfy incineration efficiency and nitrogen oxides ultra-low emission requirements, it is of great importance to improve the operational performance of the municipal solid waste incineration (MSWI) process. However, due to the complex and fluctuating composition of municipal solid waste, it is challenging to guarantee optimal operation under changing conditions. To address this issue, a multi-condition operational optimization method based on adaptive knowledge transfer (MCOO-TR) is proposed for the MSWI process. First, an integrated optimization scheme, where different operation conditions are identified based on cluster analysis and expert knowledge, is developed. Second, a surrogate-assisted multi-objective particle swarm optimization algorithm is designed to solve the data-driven optimization problems for optimal operation, where the surrogate model selection mechanism is proposed to cope with multi-condition characteristics. Third, an adaptive knowledge transfer strategy, corresponding to condition identification, is designed aiming to improve optimization efficiency. Finally, the proposed MCOO-TR method is evaluated based on actual industrial data. The experimental results demonstrate that the MCOO-TR method can achieve satisfactory operational performance under changing operation conditions.

Evaluation of thermal management technologies for fuel efficient cold-start emissions reduction in diesel engines

The ultra-low NOx emission limits for heavy and mid-duty vehicles, which are expected to be imposed in both Europe and the USA by 2027, together with the enforcement of continuous decrease in CO2 emission levels, make the need for adoption of newer technologies in the automotive industry imperative. To achieve low tailpipe NOx emissions, the accelerated warm-up of the exhaust aftertreatment system is of great importance. On the other hand, the thermal management strategies applied for this purpose result in fuel consumption penalty and consequently higher CO2 as it can be widely found in the literature. Thus, the use and optimization of advanced thermal management technologies is critical to decrease the NOx– fuel penalty trade-off on the basis of complete driving cycles. In the present work an integrated modeled-based approach is implemented by coupling advanced, predictive 1D engine, and aftertreatment simulation models which are extensively validated via dedicated experimental data. The main goal of this approach is to define and investigate multiple engine or aftertreatment-based thermal management technologies, as well as a combination of them, creating a more efficient warm-up mode for the engine. Thermal measures such as cylinder deactivation, retarded start of the main injection, late intake valve closing (Miller cycle), intake throttling, elevated idle speed, and secondary fuel injection upstream the DOC are evaluated for their effect on the exhaust system heat-up time, the fuel consumption penalty and more importantly, for their impact on the tailpipe NOx emissions calculated by this holistic simulation approach.

Impact of the central London Ultra-Low Emission Zone and toxicity-charge on adult emergency hospital admissions: An interrupted time series analysis

Impact of the central London Ultra-Low Emission Zone and toxicity-charge on adult emergency hospital admissions: An interrupted time series analysis

Study on Dynamic Characteristics of Magnetic Coagulation of Fe-Based Fine Particles in Iron and Steel Industry

Fine dust, represented by Fe-based fine particles and emitted from the production process of the iron and steel industry, is the primary factor causing many diseases represented by industrial pneumoconiosis, and ultra-low dust emission has always been a thorny problem to be solved urgently. To explore the magnetic coagulation effect of Fe-based fine particles in the magnetic field when removing them from industrial flue gas by the magnetic field effect in the iron and steel industry, using FLUENT software, magnetic dipole force was added between particles through user defined function (UDF) based on the computational fluid dynamics-discrete phase model (CFD-DPM) method so that the collision process of particles was then equivalent to their mutual trapping process. Next, the effects of particle size, particle volume fraction, external magnetic field strength, and particle magnetic susceptibility on the magnetic coagulation process were comprehensively studied. Meanwhile, the proton balance equation (PBE) was solved using the partition method on the basis of the computational fluid dynamics-population balance model (CFD-PBM) to compare the coagulation removal effect under random and aligned orientations of magnetic dipoles, respectively. The results showed that the magnetic coagulation strength under the random orientation of magnetic dipoles was greater than that under the aligned orientation. When the particle size of Fe-based fine particles increased from 0.5 μm to 1.5 μm, the magnetic coagulation coefficient decreased from 0.5414 to 0.2882, and the difference in the removal efficiency under the two different orientations of magnetic dipoles became smaller. When the particle volume fraction increased from 0.01 to 0.03, the magnetic coagulation coefficient increased from 0.2353 to 0.5061, and the difference in the removal efficiency under two orientations was enlarged. When the applied external magnetic field strength increased from 0.5 T to 1.0 T, the magnetic coagulation coefficient increased from 0.3940 to 0.5288, and the magnetic susceptibility increased from 0.0250 to 0.0500, the coagulation coefficient increased from 0.3940 to 0.5288, and the difference under two orientations basically stayed unchanged.

Ammonia emission characteristics and ammonia injection control from stationary source in flue gas denitrification system

With the implementation of ultra-low emission of nitrogen oxides, denitrification technologies, such as selective catalytic reduction, selective non-catalytic reduction or selective non-catalytic reduction combined with selective catalytic reduction, have been widely used in gas-fired power plants, cement plants and municipal solid waste incineration power plants. These three denitrification industries have become the main potential fixed sources of ammonia emissions in urban areas, however the studies on ammonia emissions are lacking. In order to study the ammonia emission characteristics and ammonia injection control of gas-fired power plants, cement plants and municipal solid waste incineration power plants, field tests were carried out on five typical denitrification enterprises using three monitoring methods. The multi-form ammonia manual monitoring method proposed in this study distinguished and defined all possible ammonia in the flue gas into filterable ammonia, residual ammonia, condensable ammonia and gaseous ammonia according to the migration and transformation behavior during the collection process. The monitoring results of the multi-form manual monitoring method can more accurately reflect the actual ammonia emission level with the simultaneous collection and monitoring of different ammonia forms. The ammonia emission levels in cement plants (more than 20 mg/m³) were higher than that of gas power plants and waste incineration plants (almost less than 4 mg/m³). The condensed ammonia was the dominant form of ammonia, accounting for 58.4%～88.7%. The humidity and temperature of flue gas at the chimney outlet had significant influence on residual ammonia. For the denitration enterprises using a single denitrification technology, the ammonia emission had a linear negative correlation with that of nitrogen oxide with changing ammonia injection amount, while for that using combined denitrification technology, the degree of collaboration between selective non-catalytic reduction ammonia injection control and selective catalytic reduction ammonia injection control played a decisive role in the control of nitrogen oxide emission and ammonia emission, especially the selective catalytic reduction ammonia injection control.

Summer thermal and energy performances assessment of a modular hydronic thermal barrier wall for ultra-low energy buildings - A field experimental study

Hydronic thermal barriers with ultra-low carbon emission attributes are progressively gaining prominence in the competition of thermal insulation solutions for opaque envelopes of low-energy buildings due to their excellent thermal performance and low-grade energy utilization potential. This paper introduces a novel approach involving a modular hydronic thermal barrier wall (MHTB) that incorporates preset pipe cavities and replaceable filling material. This proposition seeks to address the challenges confronted by conventional hydronic thermal barrier walls (CHTBs), specifically in terms of internal heat transfer enhancement and rapid assembly/dismantling. On-site thermal performance tests and energy-saving evaluations were conducted in summer conditions based on three scaled-down rooms with MHTB, CHTB and a conventional external insulation wall as the south walls. The results showed that the MHTB could significantly reduce heat passing through the south wall in summer, resulting in a decreased cooling load attributed to the wall and subsequently lowering indoor temperatures. At a charging temperature of 17.0 °C, the MHTB exhibited a reduction of 11.3 °C in interior surface temperature compared to the conventional external insulation wall, accompanied by a corresponding increase of 2.76 kWh·m−2 in cumulative heat flux. In addition, the MHTB could effectively mitigate inhomogeneous heat transfer within the wall, enhancing the overall heat transfer effect. Across the four investigated conditions, the MHTB with a steel grit-sand mixture as the filling material demonstrated an approximate 4.7% increase in cumulative heat flux and a 12.2% enhancement in cumulative cooling quantity compared to the CHTB. Overall, the findings substantiated the efficacy of the MHTB system and offered a crucial point of reference for advancing research in optimizing the performance and modular construction of hydronic thermal barrier walls.

Study and management of flow and concentration field problems in 600 MW SCR unit

With the increasingly stringent national requirements for environmental protection, the control of pollutants in coal-fired power plants has been gradually strengthened. In order to meet the NOx emission standard, some coal-fired units achieve ultra-low emissions by excessive ammonia injection, which seriously affects the unit operation economy. This paper takes the SCR denitrification unit of a 600 MW coal-fired unit with a Π-type furnace in China as the research object and studies the distribution of flow and concentration fields inside the unit under a 60% load section by means of CFD numerical simulation. It points out the problems of flow and concentration fields at local locations under current operating conditions and proposes the rectification of the corresponding area of the inflow equipment and the idea of a zonal ammonia injection optimization method. It provides a certain reference value for the optimized management of the denitrification system of coal-fired units in the future.

Study on desulfurization performance of Cu modified red mud-fly ash sorbent

In this paper, fly ash, red mud and Cu(NO3)2·3H2O were used to prepare Cu modified red mud-fly ash sorbent (CuRMFA) by hydration impregnation method, and the sorbent was used to remove SO2 from coal-fired flue gas. The effects of Cu loading and removal conditions (temperature, O2 concentration and NO concentration) on the desulfurization ability of sorbent were studied. The desulfurization performance and mechanism of CuRMFA were analyzed by experimental results and characterizations. The experimental results show that the sorbent CuRMFA can meet the ultra-low emission standard of SO2, and the optimal load of Cu is 20 mg/g. The optimal removal conditions were 500 ℃, 5% O2, 50 mg/m3 NO and 500 mg/m3 SO2, and when the desulfurization efficiency was greater than 93%, the breakthrough time and sulfur capacity were 65.5 min and 230.88 mg/g, respectively. The CuRMFA mainly removes SO2 by chemical reaction, and the desulfurized product exists in the form of SO42-. The conversion of Cu+ to Cu2+ can enhance the electron transfer, enhance the adsorption oxygen conversion and catalytic oxidation performance, which plays an important role in improving the desulfurization performance of the CuRMFA. That Cu modified RMFA is beneficial to form active component 2MgO·SiO2 and decompose of (CaO)12·(Al2O3)7, and can promote the uniform dispersion of active component, which is conducive to reducing the activation energy of desulfurization reaction and speeding up the reaction process.

Development Progress of a 70% Efficient Hybrid SOFC-I.C. Engine Hybrid System for Stationary Applications up to 1 MW

Flexible and dispatchable, high-efficiency power generation supplied with carbon-neutral renewable fuels is needed to help enable defossilization of the electric grid. Pressurized, hybrid SOFC systems fueled with hydrogen, biogas, or renewable natural gas can generate clean power at ultra-high efficiency. This presentation presents an update on the development progress of a full-scale, hybrid system that targets low cost (<1000 $/kW) and ultra-high efficiency (70%-LHV) distributed power generation for applications up to 1 MW. The system features mature, metal-supported SOFC technology and the system design, control, hardware integration, and demonstration activities are funded by the U.S. DOE ARPA-E INTEGRATE Program. Some of the more novel aspects of the system include the intermediate operating cell temperature (600°C) and internal reforming capabilities which enable excellent thermal management and effectively reduce air preheater duty by >60% over more conventional SOFC systems operating near 800°C. Pressurization of the system decreases area specific resistance (ASR) and increases stack power density, thereby lowering capital cost. The use of a gasified diesel engine converts the residual chemical exergy in the anode tail-gas from the SOFC to drive auxiliaries and produce net additional power. Furthermore, the syngas engine enables a simple engine after-treatment for achieving ultra-low engine emissions (NOx, CO, PM, UHC). Updates on critical hardware advancements around pressurized multi-stack, 30 kW fuel cell modules, low-speed high efficiency rotating equipment, and ultra-high efficiency power electronics are provided. Results from experimental testing, system design and layout, and demonstration test facility capabilities are presented and discussed. The presentation concludes with a techno-economic outlook for such power generation systems in various stationary applications, as well as comparison with competing distributed generation technologies, such as solar PV-battery systems, microturbines, stationary engines, and non-hybridized SOFC technologies. Figure 1

Indocyanine green based fluorescence imaging improved by deep learning.

Intraoperative identification of malignancies using indocyanine green (ICG) based fluorescence imaging could provide real-time guidance for surgeons.Existing ICG-based fluorescence imaging mostly operates in the NIR-I (700-1,000 nm) or the NIR-IIa' windows (1,000-1,300 nm), which not optimal in terms of spatial resolution and contrast since their light scattering is higher than the NIR-IIb window (1,500-1,700 nm). It is highly desired to achieve ICG-based fluorescence imaging in the NIR-IIb window, but it is hindered by its ultra-low NIR-IIb emission tail of ICG. Herein we employ a generative adversarial network (GAN) to generate NIR-IIb ICG images directly from the acquired NIR-I ICG images. This approach was investigated by in vivo imaging of sub-surface vascular, intestine structure, and tumors, and their results demonstrated significant improvement in spatial resolution and contrast for ICG-based fluorescence imaging. It is potential for deep learning to improve ICG-based fluorescence imaging in clinical diagnostics and image-guided surgery in clinics. This article is protected by copyright. All rights reserved.

Comprehensive energy efficiency analysis of ultra-supercritical thermal power units

At present, ultra-supercritical power plant is the most advanced technology, which can achieve ultra-low pollutant emissions and greatly improve the energy efficiency of power plant. In this paper, the key factors affecting the energy efficiency of thermal power unit are analyzed. Moreover, the way in which these factors affect the energy efficiency of thermal power unit is obtained. Besides, this study lay a solid foundation for subsequent improvements in the energy efficiency of thermal power unit. First, a mathematical mechanism model of ultra-supercritical thermal power units is established. In addition, Aspen Plus software is used to build a full process simulation model of thermal power unit. In addition, a methodology for energy efficiency analysis based on the exergy balance theory is presented, and energy efficiency evaluation indicators are defined. Finally, the TOPSIS method was used to rank the key factors affecting the energy efficiency of thermal power unit. Based on experimental analysis, this study found that in comparison to general unit, the ultra-supercritical thermal power units has improved boiler efficiency by approximately 2%, power generation efficiency by approximately 6.77%, carbon emissions by approximately 0.027 t/h and the exergy efficiency by approximately 2.91%, providing better energy efficiency and lower carbon emissions.