Alignment and Misalignment of Technology Push and Regulatory Pull: Federal RD&D Support for SO₂ and NOx Emissions Control Technology for Coal-Fired Power Plants, 1970-2000

2010 ◽  
Author(s):  
David M. Hart ◽  
Kadri Kallas
Keyword(s):  
Power Plants ◽  
Nox Emissions ◽  
Control Technology ◽  
Emissions Control

scholarly journals The effect of coal-fired power-plant SO<sub>2</sub> and NO<sub>x</sub> control technologies on aerosol nucleation in the source plumes

2012 ◽  
Vol 12 (23) ◽  
pp. 11519-11531 ◽  
Author(s):  
C. R. Lonsdale ◽  
R. G. Stevens ◽  
C. A. Brock ◽  
P. A. Makar ◽  
E. M. Knipping ◽  
...  
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
Particle Formation ◽  
Particle Nucleation ◽  
Nox Emissions ◽  
Emissions Control ◽  
So2 Emissions ◽  
The Us ◽  
Order Of Magnitude ◽  
Control Technologies

Abstract. Nucleation in coal-fired power-plant plumes can greatly contribute to particle number concentrations near source regions. The changing emissions rates of SO2 and NOx due to pollution-control technologies over recent decades may have had a significant effect on aerosol formation and growth in the plumes with ultimate implications for climate and human health. We use the System for Atmospheric Modeling (SAM) large-eddy simulation model with the TwO-Moment Aerosol Sectional (TOMAS) microphysics algorithm to model the nucleation in plumes of coal-fired plants. We test a range of cases with varying emissions to simulate the implementation of emissions-control technologies between 1997 and 2010. We start by simulating the W. A. Parish power plant (near Houston, TX) during this time period, when NOx emissions were reduced by ~90% and SO2 emissions decreased by ~30%. Increases in plume OH (due to the reduced NOx) produced enhanced SO2 oxidation and an order-of-magnitude increase in particle nucleation in the plume despite the reduction in SO2 emissions. These results suggest that NOx emissions could strongly regulate particle nucleation and growth in power-plant plumes. Next, we test a range of cases with varying emissions to simulate the implementation of SO2 and NOx emissions-control technologies. Particle formation generally increases with SO2 emission, while NOx shows two different regimes: increasing particle formation with increasing NOx under low-NOx emissions and decreasing particle formation with increasing NOx under high-NOx emissions. Next, we compare model results with airborne measurements made in the W. A. Parish power-plant plume in 2000 and 2006, confirming the importance of NOx emissions on new particle formation and highlighting the substantial effect of background aerosol loadings on this process (the more polluted background of the 2006 case caused more than an order-of-magnitude reduction in particle formation in the plume compared to the cleaner test day in 2000). Finally, we calculate particle-formation statistics of 330 coal-fired power plants in the US in 1997 and 2010, and the model results show a median decrease of 19% in particle formation rates from 1997 to 2010 (whereas the W. A. Parish case study showed an increase). Thus, the US power plants, on average, show a different result than was found for the W. A. Parish plant specifically, and it shows that the strong NOx controls (90% reduction) implemented at the W. A. Parish plant (with relatively weak SO2 emissions reductions, 30%) are not representative of most power plants in the US during the past 15 yr. These results suggest that there may be important climate implications of power-plant controls due to changes in plume chemistry and microphysics, but the magnitude and sign of the aerosol changes depend greatly on the relative reductions in NOx and SO2 emissions in each plant. More extensive plume measurements for a range of emissions of SO2 and NOx and in varying background aerosol conditions are needed, however, to better quantify these effects.

Research Advances of NOx Emissions Control Technologies of Stoker Boilers

2012 ◽  
Vol 562-564 ◽  
pp. 1087-1090
Author(s):  
Jia You Liu ◽  
Feng Zhong Sun
Keyword(s):  
Nitrogen Oxides ◽  
Human Health ◽  
Coal Combustion ◽  
Nox Emissions ◽  
Control Technology ◽  
Control Methods ◽  
Emissions Control ◽  
Thermal Nox ◽  
Control Technologies ◽  
And Control

Nitrogen oxides (NOx) are one of the pollutants generating from coal combustion in stoker boilers, and they are very harmful to human health and environment. It is necessary to study NOx emissions control technology for stoker boilers. By explaining the formation mechanism and control methods of thermal NOx, fuel NOx and prompt NOx, NOx emissions control technologies applied in stoker boilers are introduced and research advances are given, some advice for NOx emissions control in stoker boilers is put forward.

scholarly journals Changes in Power Plant NOx Emissions over Northwest Greece Using a Data Assimilation Technique

Atmosphere ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 900
Author(s):  
Ioanna Skoulidou ◽  
Maria-Elissavet Koukouli ◽  
Arjo Segers ◽  
Astrid Manders ◽  
Dimitris Balis ◽  
...  
Keyword(s):  
Power Plant ◽  
Data Assimilation ◽  
Energy Production ◽  
Power Plants ◽  
Transport Model ◽  
A Priori ◽  
Filter Method ◽  
Nox Emissions ◽  
A Posteriori ◽  
Data Assimilation Technique

In this work, we investigate the ability of a data assimilation technique and space-borne observations to quantify and monitor changes in nitrogen oxides (NOx) emissions over Northwestern Greece for the summers of 2018 and 2019. In this region, four lignite-burning power plants are located. The data assimilation technique, based on the Ensemble Kalman Filter method, is employed to combine space-borne atmospheric observations from the high spatial resolution Sentinel-5 Precursor (S5P) Tropospheric Monitoring Instrument (TROPOMI) and simulations using the LOTOS-EUROS Chemical Transport model. The Copernicus Atmosphere Monitoring Service-Regional European emissions (CAMS-REG, version 4.2) inventory based on the year 2015 is used as the a priori emissions in the simulations. Surface measurements of nitrogen dioxide (NO2) from air quality stations operating in the region are compared with the model surface NO2 output using either the a priori (base run) or the a posteriori (assimilated run) NOx emissions. Relative to the a priori emissions, the assimilation suggests a strong decrease in concentrations for the station located near the largest power plant, by 80% in 2019 and by 67% in 2018. Concerning the estimated annual a posteriori NOx emissions, it was found that, for the pixels hosting the two largest power plants, the assimilated run results in emissions decreased by ~40–50% for 2018 compared to 2015, whereas a larger decrease, of ~70% for both power plants, was found for 2019, after assimilating the space-born observations. For the same power plants, the European Pollutant Release and Transfer Register (E-PRTR) reports decreased emissions in 2018 and 2019 compared to 2015 (−35% and −38% in 2018, −62% and −72% in 2019), in good agreement with the estimated emissions. We further compare the a posteriori emissions to the reported energy production of the power plants during the summer of 2018 and 2019. Mean decreases of about −35% and−63% in NOx emissions are estimated for the two larger power plants in summer of 2018 and 2019, respectively, which are supported by similar decreases in the reported energy production of the power plants (~−30% and −70%, respectively).

Fingerprints of a New Normal Urban Air Quality in S5P TROPOMI Tropospheric NO2 Observations

2021 ◽  
Author(s):  
Shobha Kondragunta
Keyword(s):  
United States ◽  
Air Quality ◽  
Unemployment Rate ◽  
Power Plants ◽  
The United States ◽  
Urban Air Quality ◽  
Urban Air ◽  
Nox Emissions ◽  
Percentage Increase ◽  
New Normal

&lt;p&gt;Most countries around the world took actions to control COVID-19 spread that included social distancing, limiting air and ground travel, closing schools, suspending sports leagues, closing factories etc., leading to&amp;#160; economic shutdown. The reduced traffic and human movement compared to Business as Usual (BAU) scenario was tracked by Apple and Android cellphone use; the data showed substantial reductions in mobility in most metropolitan areas.&amp;#160; We analyzed reductions in on-road mobile NOx emissions from light and heavy duty vehicles in four major metropolitan and one rural areas in the United States that showed a reduction in NOx mobile emissions from 9% to 19% between February and March at the onset of lockdown in the middle of March; between March and April, the mobile NOx emissions dropped further by 8% to 31% when lockdown measures were the most stringiest.&amp;#160; These precipitous drops in NOx emissions correlated well with tropospheric NO&lt;sub&gt;2&lt;/sub&gt; column amount observed by Sentinel 5 Precursor TROPospheric Ozone Monitoring Instrument (S5P TROPOMI).&amp;#160; Further, the changes in TROPOMI tropospheric NO&lt;sub&gt;2&lt;/sub&gt; across the continental U.S. between 2020 and 2019 correlated well with changes in on-road NOx emissions (r=0.78) but correlated weakly with changes in emissions from the power plants (r=0.44). These findings confirm that power plants are no longer the major source of NO&lt;sub&gt;2&lt;/sub&gt; in the United States. We also examined correlation between increase in unemployment rate between 2020 and 2019 to decrease in tropospheric NO&lt;sub&gt;2&lt;/sub&gt; amount.&amp;#160; The negative correlation indicates that with increased unemployment rate combined with telework policies across the nation for non-essential workers, the NO&lt;sub&gt;2&lt;/sub&gt; values decreased at the rate of 0.8 &amp;#181;moles/m&lt;sup&gt;2&lt;/sup&gt; decrease per unit percentage increase in unemployment rate.&amp;#160; There is a substantial amount of scatter in the data with some cities such as Atlanta, Dallas, and Houston showing no noticeable trend in tropospheric NO&lt;sub&gt;2&lt;/sub&gt; changes during the time period when unemployment rate increased from 6% to 12%.&amp;#160;&amp;#160; We examined the trends in on-road and power plant emissions for five different locations (four urban areas and one rural area) and show that the changes in NOx emissions during the lockdown are detectable in TROPOMI tropNO2 data, the economic indicators are consistent with emissions changes, and the trends reversing with the removal of lockdown measures in the major metro areas have not come back to pre-pandemic levels.&amp;#160; The COVID-19 pandemic experience has provided the scientific community an opportunity to identify emissions reductions scenarios that created a new normal for urban air quality and if the environmental protection agencies should look at this new normal as a guidance for instituting new policies.&amp;#160;&lt;/p&gt;

Prediction of NOx emissions for coal-fired power plants with stacked-generalization ensemble method

Fuel ◽  
2020 ◽  
pp. 119748
Author(s):  
Zhaowei Yuan ◽  
Lei Meng ◽  
Xiaobing Gu ◽  
Yuyong Bai ◽  
Huanmin Cui ◽  
...  
Keyword(s):  
Power Plants ◽  
Ensemble Method ◽  
Nox Emissions ◽  
Stacked Generalization

Closed-Loop Combustion Control Using OH Radical Emissions

2000 ◽  
Author(s):  
Zhu (Julie) Meng ◽  
Robert J. Hoffa ◽  
Charles A. DeMilo ◽  
Todd T. Thamer
Keyword(s):  
Control System ◽  
Simulation Model ◽  
Gas Turbine ◽  
Closed Loop ◽  
System Simulation ◽  
Combustion Process ◽  
Operating Conditions ◽  
Nox Emissions ◽  
Oh Radical ◽  
Emissions Control

The combustion process in gas-turbine engines produces emissions, especially nitrogen oxides (NOx) and carbon monoxide (CO), which change dramatically with combustor operating conditions. As part of this study, the application of active feedback control technologies to reduce thermal NOx emissions is modeled numerically and demonstrated experimentally. A new optical flame sensor, designed by Ametek Power & Industrial Products, has been successfully implemented as the feedback element in a proof-of-concept control system used to minimize NOx emissions. The sensor consists of a robust mechanical package, as well as electronics suitable for severe gas-turbine environments. Results from system rig tests correlate closely to theoretical predictions, as described in literature and produced by a control system simulation model. The control system simulation model predicts the efficacy of controlling engine operating characteristics based on chemical luminescence of the OH radical. The model consists of a fuel pump and metering device, a fuel-air mixing scheme, a combustion model, the new ultraviolet (UV) feedback flame sensor, and a simple gain block. The input reference to the proportional emissions control is the fuel-to-air equivalence ratio, which is empirically correlated to the desired low level of NOx emissions while satisfying other operating conditions, such as CO emissions and power. Results from the closed-loop emissions control simulation and rig tests were analyzed to determine the capability of the UV flame sensor to measure and control the combustion process in a gas-turbine engine. The response characteristics, overshoot percentage, rise time, settling time, accuracy, resolution, and repeatability are addressed.

Model-Based Analysis of the Start-Up Improvement of a CCPP due to Steam Turbine Warm-Keeping With Air

2019 ◽  
Author(s):  
Dennis Toebben ◽  
Tobias Burgard ◽  
Sebastian Berg ◽  
Manfred Wirsum ◽  
Liu Pei ◽  
...  
Keyword(s):  
Power Plant ◽  
Steam Turbine ◽  
Power Plants ◽  
Cold Start ◽  
Nox Emissions ◽  
Data Set ◽  
Water Steam ◽  
Hot Air ◽  
Start Up ◽  
Low Load

Abstract Combined cycle power plants (CCPP) have many advantages compared to other fossil power plants: high efficiency, flexible operation, compact design, high potential for combined heat and power (CHP) applications and fewer emissions. However, fuel costs are relatively high compared to coal. Nevertheless, major qualities such as high operation flexibility and low emissions distinctly increase in relevance in the future, due to rising power generation from renewable energy sources. An accelerated start-up procedure of CCPPs increases the flexibility and reduces the NOx-emissions, which are relatively high in gas turbine low load operation. Such low load operation is required during a cold start of a CCPP in order to heat up the steam turbine. Thus, a warm-keeping of the thermal-limiting steam turbine results in an accelerated start-up times as well as reduced NOx-emissions and lifetime consumption. This paper presents a theoretical analysis of the potential of steam turbine warm-keeping by means of hot air for a typical CCPP, located in China. In this method, the hot air passes through the steam turbine while the power plant is shut off which enables hot start conditions at any time. In order to investigate an improved start-up procedure, a physical based simplified model of the water-steam cycle is developed on the basis of an operation data set. This model is used to simulate an improved power plant start-up, in which the steam turbine remains hot after at least 120 hours outage. The results show a start-up time reduction of approximately two-thirds in comparison to a conventional cold start. Furthermore, the potential of steam turbine warm-keeping is discussed with regards to the power output, NOx-emissions, start-up costs and lifetime consumption.

scholarly journals Evolution of SO2 and NOx Emissions from Several Large Combustion Plants in Europe during 2005–2015

2020 ◽  
Vol 17 (10) ◽  
pp. 3630 ◽  
Author(s):  
Daniel-Eduard Constantin ◽  
Corina Bocăneala ◽  
Mirela Voiculescu ◽  
Adrian Roşu ◽  
Alexis Merlaud ◽  
...  
Keyword(s):  
Power Plants ◽  
Standard Procedure ◽  
Air Pollutant ◽  
Satellite Observations ◽  
Pollutant Emissions ◽  
Nox Emissions ◽  
The European Union ◽  
Ozone Monitoring Instrument ◽  
Eu Directives ◽  
The Eu

The aim of this paper is to investigate the evolution of SO2 and NOx emissions of ten very large combustion plants (LCPs >500 MW) located in the European Union (EU) during 2005–2015. The evolution of NOx and SO2 emissions were analyzed against the EU Directives in force during 2005–2015. The investigation was performed using space-borne observations and estimated emissions collected from the EEA (European Environment Agency) inventory of air pollutant emissions. The power plants were chosen according to their capacity and emissions, located in various parts of Europe, to give an overall picture of atmospheric pollution with NOx and SO2 associated with the activity of very large LCPs in Europe. Satellite observations from OMI (Ozone Monitoring Instrument) are compared with calculated emissions in order to assess whether satellite observations can be used to monitor air quality, as a standard procedure, by governmental or nongovernmental institutions. Our results show that both space observations and estimated emissions of NOx and SO2 atmospheric content have a descending trend until 2010, complying with the EU Directives. The financial and economic crisis during 2007–2009 played an important role in reducing emissions.

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