On Countermeasures and Suggestions to Control NO_X Emissions from Utility Boilers

In combination with low NOX combustion techniques inChina and in view of limits of the Standard of Discharging Atmo-spheric Pollutants from Thermal Power Plants to be published soon,this paper presents corresponding technical countermeasures andkey subjects to be studied.

Thinking About the New Atmospheric Pollutant Emission Standard for Thermal Power Plants

China's new Atmospheric Pollutant Emission Standard for Thermal Power Plants has been made the most stringent atmospheric pollutant emission limit in the world,with the intensified control of nitrogen oxides in the air pollutants emitted by thermal power plants,the tightened limit on the emission of sulfur dioxide,and the widened range of control including mercury and other compounds discharge.The adoption of the new standard will considerably impact the survival and development of power plants,even the whole economy of the nation.While implementing all the policies and measures on emission reduction issued by the State to fulfill political,social,and economic responsibilities,China Huadian Corporation,one of the leading state-owned power generation groups,is actively exploring the green and low-carbon path for the sound and rapid development of the group.

Challenges from the New Emission Standards for SO_2 and NO_X

The Emission Standards of Air Pollutants from Thermal Power Plants (GB 13223-2011) prescribe a stricter limitation to air pollutants than ever before. As set in the new emission standard, the limitations of SO2 and NOX for sensitive areas under normal conditions are 50 mg/m3 and 100 mg/m3, respectively. The objective analysis and suggestions are proposed. The recent status and operational experience of desulfurization and denitrification equipment are discussed. From the discussions, thermal power plants face a huge challenge to satisfy the new emission standards. For further reducing of the emission concentrations of SO2 and NOX, three methods were introduced, including: seriously implementing the emission standards, improving treatment equipment, and increasing the efficiencies of desulfurization and denitrification.

How Do Power Enterprises Deal with Total Quantity Control

This paper describes the relation and difference of "emission up to standards" and "total quantity control" ofmain atmospheric pollutants, as well as their legal status. It points out that the total quantity control is a good approachto solve a problem that environmental quality do not yet reach the requirements in an area where emission concentrationhas came up to standards, or to solve a problem that the interregional transportation of pollutants (e. g. acid rain) arises.And further, it put forward five proposals for the total quantity control.[

Improving Designs of CA6DF2 Series Diesel Combustion System

The technical improvements are made based on the former CA6110 diesel engine to meet the requirements of Euro Ⅱ emission standards. The performance and emission for CA6DF1 and CA6DF2 are all met the demand of design by improving the fuel, combustion and supercharging systems. The injection system adopts high-pressure pump-pipe-injector injection system. To enhance the injection pressure, the methods of augmenting plunger diameter, decreasing the nozzle hole diameter and reducing the inner diameter of the high-pressure fuel pipe are adopted. The design of combustion chamber and the match of inner fuel distributions with air motion are based on a great deal of experimental database and some simple computer-aided methods, which ensure the optimization of performance and provide the guide for experimental development.

A new prediction method of industrial atmospheric pollutant emission intensity based on pollutant emission standard quantification

Industrial emissions are the main source of atmospheric pollutants in China.Accurate and reasonable prediction of the emission of atmospheric pollutants from single enterprise can determine the exact source of atmospheric pollutants and control atmospheric pollution precisely.Based on China’s coking enterprises in 2020,we proposed a quantitative method for pollutant emission standards and introduced the quantification results of pollutant emission standards(QRPES)into the construction of support vector regression(SVR)and random forest regression(RFR)prediction methods for SO_(2) emission of coking enterprises in China.The results show that,affected by the types of coke ovens and regions,China’s current coking enterprises have implemented a total of 21 emission standards,with marked differences.After adding QRPES,it was found that the root mean squared error(RMSE)of SVR and RFR decreased from 0.055 kt/a and 0.059 kt/a to 0.045 kt/a and 0.039 kt/a,and the R2 increased from 0.890 and 0.881 to 0.926 and 0.945,respectively.This shows that the QRPES can greatly improve the prediction accuracy,and the SO_(2) emissions of each enterprise are highly correlated with the strictness of standards.The predicted result shows that 45%of SO_(2) emissions from Chinese coking enterprises are concentrated in Shanxi,Shaanxi and Hebei provinces in central China.The method created in this paper fills in the blank of forecasting method of air pollutant emission intensity of single enterprise and is of great help to the accurate control of air pollutants.

Suggestion on further strengthening ultra-low emission standards for PM emission from coal-fired power plants in China

China has established the largest clean coal-fired power generation system in the world by accomplishing the technological transformation of coal-fired power plants(CFPPs)to achieve ultra-low emission.The potential for further particulate matter(PM)emission reduction to achieve near-zero emission for CFPPs has become a hotspot issue.In this study,PM emission from some ultra-low emission CFPPs adopting advanced air pollutant control technologies in China was reviewed.The results revealed that the average filterable particulate matter(FPM)concentration,measured as the total particulate matter(TPM)according to the current national monitoring standard,was(1.67±0.86)mg/m^(3),which could fully achieve the ultra-low emission standard for key regions(5 mg/m^(3)),but that achieving the near-zero emission standard was difficult(1 mg/m^(3)).However,the condensable particulate matter(CPM),with an average concentration of(1.06±1.28)mg/m^(3),was generally ignored during monitoring,which led to about 38.7%underestimation of the TPM.Even considering both FPM and CPM,the TPM emission from current CFPPs would contribute to less than 5%of atmospheric PM_(2.5) concentrations in the key cities and regions in China.Therefore,further reduction in FPM emission proposed by the near-zero emission plan of CFPPs may have less environmental benefit than emission control of other anthropogenic sources.However,it is suggested that the management of CPM emission should be strengthened,and a national standard for CPM emission monitoring based on the indirect dilution method should be established for CFPPs.Those measurements are helpful for optimal operation of air pollutant control devices and continuously promoting further emission reduction.

Application and challenge of rare earth automotive catalysts in CHINA Ⅵ

China is setting to roll out more strict emissions rule of CHINA Ⅵ Emission Standard which poses huge challenge to automotive catalytic technology.Rare earth elements are the key compositions of the catalysts coating.To develop multiple-component rare earth materials is an important way to improve the performance of the catalyst.The study concluded that quaternary or quinary rare earth materials for CHINA Ⅵ Emission Standard,can improve substantially the oxygen storage capacity and high thermal stability of the catalyst,after the modification by Pr/NdAT elements.It improved the utilization efficiency of precious metal.

Challenges to the execution of the Euro III/IV emissions standards and proposals

As widely known, execution of the Euro III/ IV emissions standards involve two critical matters: OBD techniques and active vehicles in line with the requirements (similar to the recall system in the US). For heavy duty trucks and buses, Euro III requires

Influences of accumulated mileage and technological changes on emissions of regulated pollutants from gasoline passenger vehicles

In this study, the influences of accumulated mileage （deterioration） and technological changes （emission standards） on emission factors （EFs） of regulated pollutants （CO, HC, and NOx） from gasoline passenger vehicles were investigated based on Inspection and Maintenance （I/M） data using the chassis dynamometer method. The accumulated mileage of passenger vehicles was significantly linearly correlated with vehicle age. For most cases, the average EFs of CO, HC and NOx were significantly linearly correlated with accumulated mileage, indicating that emission deterioration had a significant impact on pollutant EFs. Implemented emission standards markedly influenced the EFs of regulated pollutants, and EFs markedly decreased with progressing emission standards. The present study also compared EFs of regulated pollutants between this study and the International vehicle emission （IVE） model, and marked differences in EFs were seen with variations in emission standards, vehicle types and accumulated mileage; NOx EFs in this study were higher than in the IVE model. The results provide new insight into estimating regulated pollutant emissions using the IVE model.

Mercury emissions in China:a general review

This paper provides a general review of the research status of mercury emissions in China.Global surveys rank Asia as the region with the largest share of global mercury emissions,accounting for almost half.China contributes about one-third of the world’s mercury emissions,which is 600-800 t per year.And thus,it plays a vital role in reducing global mercury emissions.Data since 2003 has been surveyed.Mercury emissions in China have risen in the beginning and then declined.There are differences in the composition of mercury emissions sources between China and the world,in which coal combustion and non-ferrous metals smelting contribute more than 50%of the emissions in China.Although mercury emission standards in China are close to those of the European Union and the United States,annual mercury emissions in China are four times higher than those of the United States.Mercury emissions in China are concentrated in the central and eastern regions now,but the annual mercury emissions are increasing in the western regions,which may be related to the construction of industrial parks.

HOW ARE CHINESE AUTO EMISSION STANDARDS

Since 1983, China has issued 14 motor vehicle emission control standards and 3 are for motorcycles emission control standards. See Table 1.

A More Strict Auto Emission Standard in Beijing

The most strict local auto emission standard "the emission standard on exhaust pollutant from light vehicles" draw up by Beijing Bureau of En-vironmental Protection recently will be imple-mented formally from January 1, 1999. The light vehicle manufacturers can only as-sure their position in the market of Beijing

Emission Standards for Heavy Vehicles Issued

Two local environment standards for medium and heavy vehicles, DHJB2—1999, Exhaust Pollutants E-mission Standards for Vehicle-used Gasoline Engines, DHJB3—1999, Exhaust Pollutants Emission Standards for Vehicle-used Diesel Engines, were newly issued by Environment Protection Agency of Beijing Municipali-ty. They will be enforced from Jan. 1, 2000.

New emission standards in alignment with European regulations

Four standards, GB14761 - 1999 "Limits and measurement methods for emission of pollutants from motor vehicles", GB 17691 - 1999 "Limits and measurement methods for exhaust pollutants from compression ignition (C. I.) en-gines and vehicles equipped with C. I. engines ", GB 3847-1999 "Limits and measurement

Direct identification of total and missing OH reactivities from light-duty gasoline vehicle exhaust in China based on LP-LIF measurement

Considerable efforts have been devoted to characterising the chemical components of vehicle exhaust.However,these components may not accurately reflect the contribution of vehicle exhaust to atmospheric reactivity because of the presence of species not accounted for(“missing species”)given the limitations of analytical instruments.In this study,we improved the laser photolysis–laser-induced fluorescence(LP-LIF)technique and applied it to directly measure the total OH reactivity(TOR)in exhaust gas from light-duty gasoline vehicles in China.The TOR for China Ⅰ to Ⅵ-a vehicles was 15.6,16.3,8.4,2.6,1.5,and 1.6×10^(4) sec^(-1),respectively,reflecting a notable drop as emission standards were upgraded.The TOR was comparable between cold and warm starts.The missing OH reactivity(MOR)values for China Ⅰ to Ⅳ vehicles were close to zero with a cold start but were much higher with a warm start.The variations in oxygenated volatile organic compounds(OVOCs)under different emission standards and for the two start conditions were similar to those of the MOR,indicating that OVOCs and the missing species may have similar production processes.Online measurement revealed that the duration of the stable driving stage was the primary factor leading to the production of OVOCs and missing species.Our findings underscore the importance of direct measurement of TOR from vehicle exhaust and highlight the necessity of adding OVOCs and other organic reactive gases in future upgrades of emission standards,such that the vehicular contribution to atmospheric reactivity can be more effectively controlled.

New Development of Acid Regeneration in Steel Pickling Plants

For acid pickling heat treated mild steel and steel products, up to the middle of the last century, sulfuric acid was primarily in use, which has been replaced stepwise by hydrochloric acid since the sixties. During this time, the pickling of high alloyed steel with hydrofluoric acid or mixtures for hydrofluoric acid together with nitric acid has also been applied on industrial scale. The technologies used by several plant contractors hereby show considerable differences in their engineering. The study provides a survey of the progress in the state of art of regeneration technology as well as the use of different pickl.ing media in the form of a review on existing technologies as well as improvements done within the recent years in the area.

Design and demonstration of a next-generation air quality attainment assessment system for PM_(2.5)and O_3

Due to the increasingly stringent standards, it is important to assess whether the proposed emission reduction will result in ambient concentrations that meet the standards. The Software for Model Attainment Test-Community Edition （SMAT-CE） is developed for demonstrating attainment of air quality standards of O3 and PM2.5. SMAT-CE improves computational efficiency and provides a number of advanced visualization and analytical functionalities on an integrated GIS platform. SMAT-CE incorporates historical measurements of air quality parameters and simulated air pollutant concentrations under a number of emission inventory scenarios to project the level of compliance to air quality standards in a targeted future year. An application case study of the software based on the U.S. National Ambient Air Quality Standards （NAAQS） shows that SMAT-CE is capable of demonstrating the air quality attainment of annual PM2.5 and 8-hour O3 for a proposed emission control policy.

Optimal Implementation Strategy of Carbon Emission Reduction Policy Instruments in Consideration of Cost Efficiency

In this paper, regulatory and optimum programming model has been adopted. Considering the costs of emission reduction, supervision and penalty, we went all out to analyze the optimal decision of cost efficiency of regulators when implementing these three policy instruments: carbon emission standards, carbon emission trading permissions, and carbon taxes as well. Its result has indicated: In strict accordance with control target of total carbon emissions, regulators are willing to render social and economic cost able to achieve the goal of optimal cost efficiency by regulating carbon emission standards and supervising marginal cost caused by variations in the probability; fortunately, under the conditions of low supervisory cost and certain criteria which is met, the implementation of carbon emission trading permissions could provide social and economic cost with opportunities to realize that objective; through comparative analysis, carbon emission trading permissions have the advantages of higher efficiency than carbon emission standards on the premise of incomplete information. During the implementation of carbon taxes strategy, when there exists uncertainty information in the enterprises reduction behaviors, the condition which enterprises can fully comply with is the tax rate level is not higher than marginal penalty function; the tax rate level of enterprises perfect compliance ought not to be lower than the division of marginal penalty cost and marginal supervisory cost. The optimal strategy of enterprises imperfect compliance is that regulators varying the marginal cost of emission standards is equal to varying that of supervisory probability.

NO_(x) control for high-ash coal-fired power plants in India

Many countries have strict emission limits for nitrogen oxides(NO_(x));thus NO_(x) control systems are widely deployed.India has recently introduced NO_(x) emission limits,which require that pollution control technologies must be installed on most coal-fired plants.However,operational experience with NO_(x) control systems in India is limited to primary measures only.Additionally,Indian coals have a high level of inherent ash,which is also highly erosive and can influence the behaviour of some NO_(x) control systems and thus affect the selection process.Primary measures for NO_(x) control from coal-fired power plants include low NO_(x) burners(LNBs),overfire air systems(OFA),fuel reburning,flue gas recirculation,fuel biasing,low excess air and combustion optimization.Secondary NO_(x) control includes selective catalytic reduction,selective non-catalytic reduction and multi-pollutant control systems.Retrofit of primary measures(LNBs and OFA)in India has been recommended to take place during next-scheduled plant outages;for many plants this could occur by 2019.However,control strategies for individual plants will be needed to ascertain the appropriateness of installing post-combustion technologies or various combinations of NO_(x) control measures.Hence installation of secondary NO_(x) controls is not expected before test results from secondary controls on selected Indian power plants units are known.