The Mechanisms of Flame Stabilization and Low NO_x Emission in an Eccentric Jet Pulverized Coal Combustor

The mechanisms of flame stabilization and low NO_x emission features of an eccentric jet pulverized coal com- bustor were studied through numerical modelling and experimental investigation.The results show that the formation of the unique flowfield structure is closely related to the interaction among combustor configuration, the primary jet and the control jet;and that certain rules should be followed in order to obtain the optimum condition for flame stabilization.The distributions of temperature and concentrations of NO,O_2,CO and CO_2 inside the combustor were experimentally measured.The effects of structural and operational parameters on combustion and NO formation were studied.It was found that reduction of primary air,suitable use of control jet and reasonable uptilt angle of the primary jet all contributed to the reduction of NO_x at the combustor exit. A new hypothesis,that reasonable separation of oxygen and fuel within the fuel-rich zone is beneficial to further reduction of NO_x emission,is given.The study showed that good compatibility existed between the capability of flame stabilization and low NO_x emission for this type of combustor.

Scenario analysis for the energy demand and carbon emissions in low carbon city

This paper takes the climate change and low carbon economy development as the study background, based on the analysis of energy demand and carbon emissions status, which is aimed to provide the low carbon development path in Chinese cities. The method of scenario analysis can be used to predict long-term strategy for the uncertainty future development, and it was introduced to the field of social forecasting and public policy research, such as the environmental strategic planning, policy analysis, and support of decision in resource management, which can be used to explore the possible development trend and target of the results from the macro perspective. Scenario analysis has been gradually applied to the study area on low carbon economy, energy forecasting and other fields in recent years, and there have been many research results in different aspects. This paper takes the scenario analysis as basic study theory, spreading out the present situation of its application in low carbon city and some issues that need further study. As a tool for predicting the future development in low carbon city, the method of scenario analysis has been providing a powerful reference for policies and their executants.

Advances in reduction of NO_x and N_2O emission formation in an oxy-fired fluidized bed boiler

Fossil fuel combustion is one of the major means to meet the mounting global energy demand. However, the increasing NO_x and N_2 O emissions arising from fossil fuel combustion process have hazardous effects. Thus, mitigating these gases is vital to attain a sustainable environment. Interestingly, oxy-fuel combustion in fluidized bed for carbon capture and minimized NO_x emissions is strongly sustainable compare to the other approaches. It was assessed that NO_x formation and fuel-N conversion have significant limitation under oxy-fluidized bed compared to air mode and the mechanism of NO_x formation is still deficient and requires further development. In addition, this review paper discussed the potential of primary measure as low emission process with others supplementary techniques for feasible NO_x reduction. The influences of combustion mode, operating parameters, and reduction techniques such as flue gas recirculation, oxygen staging, biomass co-firing, catalyst, influence of fluidized bed design and structure, decoupling combustion and their merges are respectively evaluated. Findings show that significant minimization of NO_x emission can be achieved through combination of primary and secondary reduction techniques.

Effect of hydrogen attack on acoustic emission behavior of low carbon steel

In order to investigate the effect of hydrogen attack degree on acoustic emission(AE) behavior of low carbon steel during tensiling, specimens made of Low carbon steel was exposed to hydrogen gas of 18 MPa at 450 and 500℃ for 240, 480 and 720 h respectively. Experimental results show that with increase of the hydrogen attack degree, the totally AE activity decreases during tensiling. In addition, the count of AE signals with high amplitude for the specimens with hydrogen attack keeps a constant which is less than that without hydrogen attack. It is concluded that AE signals originate in the specimens with hydrogen attack from intergranular fracture induced by methane blisterings or/and microcracks on grain boundaries.

Realizing Low Carbon Emission in the University Campus towards Energy Sustainability

Energy consumption increases with intensity of human activities. People consume energy for movement and other activities and the more fossil-fuel based energy used, the more carbon dioxide (CO2) emission. Since carbon dioxide is the major element of the greenhouse gases (GHG), this phenomenon has a serious implication for global warming and consequent climate change—a scenario that calls for sustainable development. This research considers the emission of CO2 from energy use within the campus of Universiti Teknologi Malaysia. Two major sources of energy consumption were identified, namely: electricity and transport. The emission for electricity was estimated based on electricity meter reading and the conversion rate in accordance with the stand-ardized conversion factors for fuel mix of the purchased electric energy as given by PTM (Pusat Tenaga Malaysia), while the associated CO2 emission for transport was estimated based on the number of miles driven (VMT—Vehicle Miles Travel) within the campus, emissions produced per litre of gasoline, and fuel economy of vehicles plying the campus in line with the Code of Federal Regulations USEPA and consistent with the Inter-governmental Panel on Climate Change (IPCC) guidelines. It was observed that high CO2 emission resulted from electricity energy consumption, and the highest emission in the transport sector was produced by commuting vehicles while emission from service delivery for cooling, lighting and other equipment was similar to national average.

Impacts of Future NO_x and CO Emissions on Regional Chemistry and Climate over Eastern China

A coupled chemical/dynamical model （SOCOL-SOlar Climate Ozone Links） is applied to study the impacts of future enhanced CO and NO_x emissions over eastern China on regional chemistry and climate. The result shows that the increase of CO and NOx emissions has significant effects on regional chemistry, including NOx, CO, O_3, and OH concentrations. During winter, the CO concentration is uniformly increased in the northern hemisphere by about 10 ppbv. During summer, the increase of CO has a regional distribution. The change in O_3 concentrations near eastern China has both strong seasonal and spatial variations. During winter, the surface O_3 concentrations decrease by about 2 ppbv, while during summer they increase by about 2 ppbv in eastern China. The changes of CO, NO_x, and O_3 induce important impacts on OH concentrations. The changes in chemistry, especially O_3, induce important effects on regional climate. The analysis suggests that during winter, the surface temperature decreases and air pressure increases in central-eastern China. The changes of temperature and pressure produce decreases in vertical velocity. We should mention that the model resolution is coarse, and the calculated concentrations are generally underestimated when they are compared to measured results. However, because this model is a coupled dynamical/chemical model, it can provide some useful insights regarding the climate impacts due to changes in air pollutant emissions.

Evaluation of the Implementation of a Low Emission Zone in Lisbon

The city of Lisbon, like many others in the EU region, introduced a Low Emission Zone (LEZ) as a tool for improving air quality in its city centre. This kind of emission reduction schemes is always controversial since it might lead to significant changes in the daily behaviours of its inhabitants. In order to evaluate the effects of the measure, an estimation of the impact of the introduction of the Lisbon LEZ was performed. Real traffic counting and fleet characterization combined with CORINAR-based emission inventory methodology allowed to estimate the impacts of three different scenarios applied to the “business as usual” condition (current vehicle fleet) ranging from “no circulation from non- compliant vehicles” to an “aggressive fleet renewal”. Results highlight the high percentage of atmospheric emissions of PM10 and NOx that might result from certain fleets like taxis and buses, especially because there was an emphasis in standardized/normalized estimations (emissions per 1000 vehicles) in order to allow different strategic approaches. The total reduction of PM10 emissions associated to each scenario vary between 6 ton.year-1 (scenario 2) and 8 ton.year-1 (scenario 1), or 25% and 34% less emissions. In terms of NOxemission reductions vary between 6 ton.year-1 (scenario 2) and 57 ton.year-1 (scenario 1), or 1% and 7% less emissions. The Lisbon LEZ is therefore much more efficient in reducing PM10 emissions compared to NOx. Major reduction in PM10 and NOx emissions are to be expected with a moderate intervention in the (relatively old) taxi fleet in Lisbon while for passenger cars the impact is limited. However in absolute terms and due to its urban mileage passenger cars should also continue being included in Lisbon LEZ. Simultaneously, an effort in the increase of dedicated lanes for public transport should be made, for further reductions in PM10 and NOx emissions.

Low-Carbon Telecom Solution for China's Emission Reduction and Future Forecasts

Based on the revised reduction models of the 14 low-carbon ICT solutions from Chongqing Mobile of the China Mobile Group,the CO2e emission reduction brought about by low-carbon ICTs of the wireless telecom sector of Chongqing Mobile,the entire China Mobile Group and the whole China in 2009 is calculated.And then the CO2e emission reduction potentials in 2010,2020 and 2030 are calculated in four main important fields of China,i.e.,intelligent transportation,dematerialization,smart work and smart appliances.The ICTs in the telecom sector are mostly dedicated to these fields.It provides a valuable insight into future reduction targets that should be set up for China.

Excitation of extremely low-frequency chorus emissions: The role of background plasma density

Low-frequency chorus emissions have recently attracted much attention due to the suggestion that they may play important roles in the dynamics of the Van Allen Belts.However, the mechanism(s) generating these low-frequency chorus emissions have not been well understood..In this letter, we report an interesting case in which background plasma density lowered the lower cutoff frequency of chorus emissions from above 0.1 f_(ce)(typical ordinary chorus) to 0.02 f_(ce)(extremely low-frequency chorus).Those extremely low-frequency chorus waves were observed in a rather dense plasma, where the number density N_e was found to be several times larger than has been associated with observations of ordinary chorus waves.For suprathermal electrons whose free energy is supplied by anisotropic temperatures, linear growth rates(calculated using in-situ plasma parameters measured by the Van Allen Probes) show that whistler mode instability can occur at frequencies below 0.1 f_(ce) when the background plasma density N_e increases.Especially when N_e reaches 90 cm–3 or more, the lowest unstable frequency can extend to 0.02 f_(ce) or even less, which is consistent with satellite observations.Therefore, our results demonstrate that a dense background plasma could play an essential role in the excitation of extremely lowfrequency chorus waves by controlling the wave growth rates.

MAGNETIC ACOUSTIC EMISSION CHARACTERISTICS OF HYDROGEN ATTACKED LOW CARBON STEEL

Hydrogen attack occurred in low carbon steel and steel 25CrMo which had been exposed in hydrogen under 18MPa at 450 and 500℃ for 240,480 and 720 h.The methane bubbles and microcracks grow along grain boundaries.The degree of hydrogen attack increases with increasing exposure time and temperature.Magnetic acoustic emission(MAE) was used to detect the degree of hydrogen attack.The results show that the characteristics of MAE for samples of low carbon steel and steel 15CrMo with hydrogen attack have changed obviously comparing to the samples without hydrogen attack,and the MAE signals was sensitive to the degree of hydrogen attack at the last stage of hydrogen attack.The magnetic detection way,as a new method of nonrestrictive testing of hydrogen attack,can be used to detect the hydrogen attack in practice.

Influence of constricted air distribution on NO_x emissions in pulverized coal combustion boiler

This paper reports a field testing of full scale PCC (Pulverized Coal Combustion) boiler study into the influence of constricted air distribution on NO x emissions at unit 3 (125 MW power units, 420 t/h boiler) of Guixi power station, Jiangxi and puts forward the methods to decrease NO x emissions and the principle of boiler operation and regulation through analyzing NO x emissions state under real running condition. Based on boiler constricted air distribution, the experiment mainly tested the influence of primary air, excessive air, boiler load and milling sets (tertiary air) on NO x emissions and found its influence characteristics. A degraded bituminous coal is simply adopted to avoid the test results from other factors.

Implement of Low Carbon Logistics Park Based on Minimizing Carbon Emissions

Based on the development of modem logistics park in China, and with the thought of minimizing carbon emission, the development of Logistics Park was analyzed and the necessity of developing low carbon Logistics Park was proposed. Low carbon emission in Logistics Park was planned. In the end, operation and implementation strategies of low carbon parks were put forward so as to create favorable environment for the re- alization of low carbon emission in Logistics Park.

Optimization and Regulation Policy for Land Use Changes Based on Low-carbon Emission in Developed Regions of China

Land use and cover change(LUCC) is one of the important causes of the Earth’s carbon cycle imbalances resulting from failure in optimizing land use. The solution to this problem has been the hotspot of research in land and environmental science. We took 'low carbon', 'energy saving' and 'high-efficiency' as the goals of land use optimization,and integrated Markov-CA(Cellular Automaton),the Grid-Fractal model and GIS,in order to study carbon emission objective function,to establish a simulation method for land use spatial allocation optimization,to evaluate the effect of the method on carbon emissions. Regulation policy on three types of land use spatial allocation was proposed,including 'low-carbon type', 'low-carbon-economic type' and 'economic type'. We applied the method to analyze the land use spatial allocation in Taixing City of the 'Yangtze River Delta' regions in China,and obtained the following results:(i) The three optimization types would improve carbon emissions by 3. 21%,1. 80% and 0. 36% respectively in 2020,compared with 2010;(ii) The actual planning for 2020 was close to the 'low-carbon-economic type';(iii) The optimization method and regulation policy,combining local optimization and global control,could meet the sustainable multi-objective requirements for low-carbon constraints of land use spatial allocation. The result of this research could also serve as a reference for exploration into patterns of regional low-carbon land use and measures for energy saving and emission reduction.

Research on Low Carbon and Reduction Emission for Transportation Industry in China

The low carbon of sustainable development of ecological economy is sweeping across the world. The logistic industry plays a key role in the economic development, which influences emission and impact of the theory of low carbon. This paper analyzes the energy consumption and carbon emission in different modes in transportation, and provides reasonable suggestions on low carbon and reduction emission for transportation industry in China.

No-catalyst growth of vertically-aligned AlN nanocone field electron emitter arrays with high emission performance at low temperature

The A1N nanostructures with a wide band-gap of 6.28 eV are considered as ideal cold cathode materials because of their low electron-affinity. Many methods have been devoted to fabricating A1N nanostructures, but high growth temperature over 800℃ and the use of the catalysts in most methods limit their practical application and result in their poor field-emission behaviours in uniformity. This paper reports that without any catalysts, a simple chemical vapour deposition method is used to synthesize aligned A1N nanocone arrays at 550℃ on silicon substrate or indium tin oxide glass. Field emission measurements show that these nanocones prepared at low temperature have an average turn-on field of 6 V/μm and a threshold field of 11.7 V/μm as well as stable emission behaviours at high field, which suggests that they have promising applications in field emission area.

Continuous Emission Spectrum Measurement for Electron Temperature Determination in Low-Temperature Collisional Plasmas

Continuous emission spectrum measurement is applied for the inconvenient diagnos- tics of low-temperature collisional plasmas. According to the physical mechanism of continuous emission, a simplified model is presented to analyze the spectrum in low temperature plasma. The validity of this model is discussed in a wide range of discharge parameters, including electron tem- perature and ionization degree. Through the simplified model, the continuous emission spectrum in a collisional argon internal inductively coupled plasma is experimentally measured to determine the electron temperature distribution for different gas pressures and radio-frequency powers. The inverse Abel transform is also applied for a better spatially resoluted results. Meanwhile, the result of the continuous emission spectrum measurement is compared to that of the electrostatic double probes, which indicates the effectiveness of this method.

Re-understanding and Thinking about Environmental Impact of Coal-fired Power Plants under Ultra-low Emission

From the perspective of development background,concepts and related policies of ultra-low emission,according to work practice,some issues and difficulties that need to be paid attention to in the environmental impact assessment of ultra-low-emission thermal power projects were discussed from the aspects of evaluation criteria,evaluation grade and scope,pollution control technical lines,environmental benefit accounting,and total emission control,and corresponding recommendations were put forward.

Study on Carbon Emission Driving Factors and Low-carbon Policy of Transportation Industry in Henan Province

The transportation industry is the basic industry of national economic development. At the same time, it is the only industry in China that has continuously increased CO2 emissions, and the high energy consumption problems have not been solved. Henan province, as a major energy consumption province, it is urgent to improve the supply quality of transportation industry. The paper uses the IPCC calculation method for carbon emission to calculate the CO2 emissions of transportation industry in Henan province from 2004 to 2014. Then, this paper uses the LMDI method to decompose the CO2 emission in the transportation industry and give the proposal to reduce the CO2 emission according to the CO2 emission drivers.

三银Low-E玻璃对减少碳排放的计算及应用研究

鉴于建筑物在其整个生命周期内的能源消耗占全球总能耗的显著比例,使用高效节能建材,是推动建筑绿色低碳化、助力实现“碳达峰”与“碳中和”目标的有效途径之一。三银Low-E玻璃凭借其独特的膜层结构,具有卓越的节能效果。为深入探究三银Low-E玻璃的碳减排性能,通过对采用不同类型银基Low-E玻璃的建筑的碳排放量进行精确测算,对比分析单、双、三银Low-E玻璃的碳减排效果,从而为三银Low-E玻璃的市场推广提供坚实的理论依据。

“双碳”目标下绿色财政政策的碳生产率效应研究

在“双碳”目标下,提高城市碳生产率是政府制定绿色财政政策推动城市低碳发展的重要考量。以两部委开展的节能减排财政政策试点为准实验,使用多期双重差分(DID)模型和塔皮奥(Tapio)脱钩指数模型,考察绿色财政政策对城市低碳发展的影响。研究显示,绿色财政政策的实施有效提升了城市碳生产率,并推动了城市低碳发展。具体而言,实施该绿色财政政策能够通过优化城市产业结构和生产要素配置、改善城市创新环境、提高城市科技创新能力等提升城市碳生产率。同时,在非资源型、非工业型、环境信息公开和地方政府环保意识强的城市中,政策效应更显著。拓展研究发现,除铁岭市和铜川市外,其他试点城市在政策实施期间经济增长速率均高于碳排放增长速率,表现出明显的碳生产率提升趋势。绿色财政政策在推动城市减碳、促增长、提升碳生产率方面发挥着重要作用,城市低碳发展应以绿色财政为抓手制定因应之策,以实现经济发展和减污降碳双重目标。