Environmental balance of an innovative waste-to-energy plant: The role of secondary emissions (original) (raw)
Related papers
Air Quality, Atmosphere & Health, 2018
Air pollution is a serious public health concern in France and many other countries. Nitrogen oxides (NO x) include nitrogen monoxide (NO) and nitrogen dioxide (NO 2). They are mainly outdoor pollutants produced during combustion of fossil fuel. These gases can easily infiltrate buildings and thus increase indoor pollution. The recommended guideline values for NO 2 are 200 µg/m 3 (short-term exposure) and 40 µg/m 3 (long-term exposure). Although no guideline values exist for NO, this gas can be oxidized by atmospheric ozone and thus produce NO 2. This paper studies the depollution efficiency of photocatalysis towards indoor NO. Experiments were conducted at real scale, in a 10-m 3 experimental chamber developed at the LMDC and used as a reactor. The interior walls of the chamber were equipped with painted plasterboards treated with photocatalytic coating (3 g/m² of TiO 2). Gas was continuously injected into the chamber according to a specific procedure: (1) pollutant injection at high flow rate to reach 200 ppb of NO, (2) pollutant injection at low flow rate in order to keep the NO concentration constant at 200±10 ppb, and (3) photocatalysis activation by switching on the light. Typical indoor lighting systems (fluorescent tubes, LED and halogen bulbs) were tested and UV fluorescent tubes were also used to optimise the photocatalytic efficiency. Results showed that NO indoor concentration was reduced by photocatalysis in real-world conditions. Significant NO degradation was obtained under visible light. In addition, using the experimental procedure presented in this paper, a new method for evaluating air depollution efficiency by photocatalysis at real scale is proposed.
Indoor air NO2 depollution by photocatalysis – comparing reactor and experimental chamber results
International Journal of Environmental Impacts: Management, Mitigation and Recovery
In spite of their positive role in the framework of circular economy, waste-to-energy processes are responsible for the emissions of a large number of air pollutants. Although this sector has made significant improvements in the air pollution control of primary emissions, the role of other sources (i.e. secondary emissions) has been often neglected. This paper aims at investigating the contributions of primary and secondary emissions expected from a waste gasification plant that is planned for the construction in an Alpine valley. The results from this analysis show that secondary emissions would play a significant role in the overall emissive footprint of the plant, contributing to 29% and 10%, respectively, of the overall emissions of dusts and total organic carbon. In the light of such results, secondary emissions would require an appropriate monitoring approach, which should complement the existing monitoring protocols for primary emissions.
Photocatalytic degradation of NO/NO2 gas injected into a 10-m3 experimental chamber
Environmental Science and Pollution Research, 2016
Indoor air is contaminated by numerous pollutants, which impact human health, comfort and productivity. These pollutants have various indoor sources such as building materials, furniture, combustion appliances or tobacco smoke. However, the pollution also comes from outside. In urban area, nitrogen oxides (NO x) emitted into the atmosphere can reach alarming levels. These traffic-related pollutants, which seriously impact the global environment and human health, can infiltrate inside buildings. Therefore, limiting the amount of breathable NO x in outdoor and indoor environments is an important priority for the modern society. The photocatalytic process has attracted particular attention in the last two decades and has proved to be efficient to reduce the concentration of NO x. However, further work has to be conducted to assess its efficiency in real indoor environments. The purpose of this paper was to report on the indoor air quality in an open space office in Manchester, UK. Focus was made on nitric oxide (NO) and nitrogen dioxide (NO 2). The indoor concentrations of both gases were monitored from 14 January 2019 to 7 April 2019. During this period, a photocatalytic coating was applied to a part of the indoor wall. The influence of this coating on the level of NO x was assessed by comparing the indoor concentrations before and after the application. An attention was paid to the correlation between outdoor and indoor pollution and to the effect of other parameters such as temperature, humidity, pressure and ozone (O 3) concentration. The results showed that the photocatalytic process led to a decrease in the NO x concentration. The likelihood to find concentrations above 35 ppb for NO and 7.5 ppb for NO 2 was clearly reduced after the coating application.
Application of photocatalytic technology for NOx removal
Applied Physics A
Materials that contain a photocatalyst have a semi-permanent capacity for removing harmful gases from the ambient air. It is the purpose of this study to investigate the photocatalytic activity of commercial paints containing TiO2 nanoparticles towards NO and NO2. Experiments were carried out in a stainless steel (30 m-3) walk-in type environmental chamber (Indoortron), under “real world setting” conditions of temperature, relative humidity, irradiation and pollutant concentrations. Two types of nanoparticle TiO2-containing paints were tested for their depolluting properties: a mineral silicate paint and a water-based styrene acrylic paint. The results showed a significant effect of TiO2-materials in reducing NOx. It was found that up to 74% of NO and 27% of NO2 were photo-catalytically degraded by the mineral silicate paint, while degradation percentage using the styrene acrylic paint reached 91% and 71% for NO and NO2, respectively. The photo-catalytic rate of NO on the mineral an...
Health and Environment
Indoor air is contaminated by numerous pollutants, which impact human health, comfort and productivity. These pollutants have various indoor sources such as building materials, furniture, combustion appliances or tobacco smoke. However, the pollution also comes from outside. In urban area, nitrogen oxides (NO x) emitted into the atmosphere can reach alarming levels. These traffic-related pollutants, which seriously impact the global environment and human health, can infiltrate inside buildings. Therefore, limiting the amount of breathable NO x in outdoor and indoor environments is an important priority for the modern society. The photocatalytic process has attracted particular attention in the last two decades and has proved to be efficient to reduce the concentration of NO x. However, further work has to be conducted to assess its efficiency in real indoor environments. The purpose of this paper was to report on the indoor air quality in an open space office in Manchester, UK. Focus was made on nitric oxide (NO) and nitrogen dioxide (NO 2). The indoor concentrations of both gases were monitored from 14 January 2019 to 7 April 2019. During this period, a photocatalytic coating was applied to a part of the indoor wall. The influence of this coating on the level of NO x was assessed by comparing the indoor concentrations before and after the application. An attention was paid to the correlation between outdoor and indoor pollution and to the effect of other parameters such as temperature, humidity, pressure and ozone (O 3) concentration. The results showed that the photocatalytic process led to a decrease in the NO x concentration. The likelihood to find concentrations above 35 ppb for NO and 7.5 ppb for NO 2 was clearly reduced after the coating application.
Photocatalytic NOx oxidation and storage under ambient conditions for air purification
2012
Ankara : The Department of Chemistry and the Graduate of Engineering and Science of Bilkent University, 2012.Thesis (Master's) -- Bilkent University, 2012.Includes bibliographical references leaves 113-123.Air pollution is one of the most serious environmental problems in both urban and rural settings with a direct impact on human health. A variety of chemical compounds can be associated with air pollution and gaseous nitrogen oxides (NOx), such as NO and NO2, are especially among the most hazardous environmental pollutants. NOx abatement can be efficiently performed at elevated temperatures (i.e. T > 300oC), however, an important challenge in air purification is the abatement of gaseous NOx species under ambient conditions (i.e. at room temperature and under regular atmospheric conditions). Photocatalytic systems offer promising opportunities in order to tackle this important environmental challenge, as these systems can be tailored to efficiently clean/purify air under ambi...
An overview of photocatalysis phenomena applied to NOx abatement
Journal of Environmental Management, 2013
This review provides a short introduction to photocatalysis technology in terms of the present environmental remediation paradigm and, in particular, NO x photoabatement. The fundamentals of photoelectrochemical devices and the photocatalysis phenomena are reviewed, highlighting the main reaction mechanisms. The critical historical developments on heterogeneous photocatalysis are briefly discussed, giving particular emphasis to the pioneer works in this field. The third part of this work focus mainly on NO x removal technology considering topics such as: TiO 2 photochemistry; effect of the operating conditions on the photocatalysis process; LangmuireHinshelwood modeling; TiO 2 photocatalytic immobilization approaches; and their applications. The last section of the paper presents the main conclusions and perspectives on the opportunities related to this technology.
Removal of NOx by photocatalytic processes
Journal of Photochemistry and Photobiology C: Photochemistry Reviews, 2013
The photocatalytic methods for nitrogen oxides removal were recently very intense areas of scientific research. Photo-deNO x processes offer interesting ways for abatement of these harmful gases. This review describes several methods for removing NO by photocatalytic reactions. These methods can be classified into three major groups: photo selective catalytic reduction (photo-SCR), photo-oxidation and photodecomposition. The application of photocatalysts and photo-processes for NO x abatement in real-scale cases are presented. The fast-growing development of these methods is revealed by the large number of issued patents in photo-deNO x applications. The mechanism of NO creation and the traditional methods (primary and secondary) of NO x removal are summarized and discussed. A cooperative system that combines the traditional (thermal) process and a photo-process is then proposed for improving NO x removal efficiency.
2017
One emerging strategy to mitigate air pollution at urban areas is the extensive use of photocatalytic products which are implemented on a vast variety of urban infrastructures. Theoretically, these mate ri ls allow removing nitrogen oxides (NOx) from the ambient air via heterogeneous photocatal ysis. This option could be especially interesting for different Europ ean urban agglomerations exceeding the limit values for NO 2 (Directive 2008/50/EC), like the case of Madrid city and the close municipalities. Nevertheless, th ere are noticeable unknowns about the real potential of these materials as NO x sink. In the framework of the LIFE MINOx-STREET European project, devoted to clarify some of the remaining technical doubts, a v ariety of commercial photocatalytic building and construction materials and coati ngs have been subjected to rigorous laboratory essays and, then, some of them sel ected in order to evaluate their impact at real scale. For this purpose, a set of ne w techniques...
Applied Catalysis B: Environmental
Titanium dioxide is the most important photocatalyst used for purifying applications. The purpose of this study was to investigate the photocatalytic activity of the commercial product Protectam FN2, containing Evonik P25 titanium dioxide nanopowder, with regard to NO and NO 2 abatement. Photocatalytic experiments on the photocatalytic coatings on concrete and plaster substrates were carried out in two types of flow reactors, namely one with laminar flow and another with ideally-mixed flow, under "real world conditions" of temperature, relative humidity, irradiation intensity and pollutant concentrations. The results showed that the photocatalytic process significantly reduced the concentration of both nitrogen oxides in the air. The reaction rate, i.e., the decrease in the concentration of NOx achieved in the steady-state for the inlet concentration of NO and NO 2 of 0.1 ppmv, which corresponds to highly polluted urban air, was up to 75 and 50 mol m −2 h −1 , respectively, at the flow rate of 3000 cm 3 min −1 and relative humidity of 50%. Further, even two years after their application to the surface of concrete walls along a busy thoroughfare, the photocatalytic coating maintained high effectivity.