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1.
Chemosphere ; 240: 124853, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31563712

RESUMEN

Co-combustion of coal and wheat straw (WS) was conducted in a lab-scale BFB combustor. Fuel composition (coal, 70%coal+30%WS), temperature (750, 800, 850, 900, 950 °C), secondary air ratio (0, 10%, 20%, 30%) were varied to on the release of gaseous pollutant was studied. CO, NOx and SO2 concentration in flue gas (FG) were measured on-line by a flue gas analyzer. Fly ash (FA), bottom slag (BS) and bed material (BM) were collected, digested and analyzed by ICP-OES to determine the distribution of heavy metals (e.g. Pb, Zn, Cr and Cd). Results indicated that co-combustion could improve the combustion of coal alone by reducing CO, NOx and SO2 emission and carbon content in fly ash effectively. In co-combustion the increasing secondary air could reduce CO emission and SO2 by enhancing disturbance and promoting sulfation respectively while the minimum NO emission was reached at the ratio of 20%. Co-combustion restrained the release of Zn, Cd and Pb compared with coal combustion alone. In co-combustion, high temperature increased their portion in the flue gas. For Zn, Pb and Cd, their content in the bottom solids increased while the portion of Cr decreased. Secondary air decreased their content in fly ash and transferred into flue gas significantly and in bottom solids content of Zn and Pb decreased while Cd increased.


Asunto(s)
Contaminantes Atmosféricos/análisis , Carbón Mineral , Metales Pesados/análisis , Triticum , Ceniza del Carbón/análisis , Gases , Incineración/instrumentación , Tallos de la Planta , Dióxido de Azufre/análisis , Temperatura
2.
Waste Manag ; 61: 283-287, 2017 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-27899246

RESUMEN

The removal of NOx by catalytic technology at low temperatures is significant for treatment of flue gas in waste incineration plants, especially at temperatures below 200°C. A novel highly active TiO2-supported vanadium oxide catalyst at low temperatures (200-250°C) has been developed for the selective catalytic reduction (SCR) de-NOx process with ammonia. The catalyst was evaluated in a pilot-scale equipment, and the results were compared with those obtained in our previous work using laboratory scale (small volume test) equipment as well as bench-scale laboratory equipment. In the present work, we have performed our experiments in pilot scale equipment using a part of effluent flue gas that was obtained from flue gas cleaning equipment in a full-scale waste incineration plant in South Korea. Based on our previous work, we have prepared a TiO2-supported V2O5 catalyst coated (with a loading of 7wt% of impregnated V2O5) on a honeycomb cordierite monolith to remove NOx from a waste incinerator flue gas at low temperatures. The NOx (nitrogen oxides) removal efficiency of the SCR catalyst bed was measured in a catalyst fixed-bed reactor (flow rate: 100m3h-1) using real exhaust gas from the waste incinerator. The experimental results showed that the V2O5/TiO2 SCR catalyst exhibited good DeNOx performance (over 98% conversion at an operating temperature of 300°C, 95% at 250°C, and 70% at 200°C), and was much better than the performance of commercial SCR catalysts (as low as 55% conversion at 250°C) under the same operating conditions.


Asunto(s)
Incineración/métodos , Óxidos de Nitrógeno/química , Compuestos de Vanadio , Catálisis , Frío , Diseño de Equipo , Incineración/instrumentación , Proyectos Piloto , República de Corea , Titanio/química , Compuestos de Vanadio/química
3.
Waste Manag Res ; 35(4): 437-443, 2017 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-27909210

RESUMEN

Degradation of polychlorinated dibenzo- p-dioxins and dibenzofurans in municipal solid waste incinerator fly ash is beneficial to its risk control. Fly ash was treated in a full-scale thermal degradation system (capacity 1 t d-1) to remove polychlorinated dibenzo- p-dioxins and dibenzofurans. Apart from the confirmation of the polychlorinated dibenzo- p-dioxin and dibenzofuran decomposition efficiency, we focused on two major issues that are the major obstacles for commercialising this decomposition technology in China, desorption and regeneration of dioxins and control of secondary air pollution. The toxic equivalent quantity values of polychlorinated dibenzo- p-dioxins and dibenzofurans decreased to <6 ng kg-1 and the detoxification rate was ⩾97% after treatment for 1 h at 400 °C under oxygen-deficient conditions. About 8.49% of the polychlorinated dibenzo- p-dioxins and dibenzofurans in toxic equivalent quantity (TEQ) of the original fly ash were desorbed or regenerated. The extreme high polychlorinated dibenzo- p-dioxin and dibenzofuran levels and dibenzo- p-dioxin and dibenzofuran congener profiles in the dust of the flue gas showed that desorption was the main reason, rather than de novo synthesis of polychlorinated dibenzo- p-dioxins and dibenzofurans in the exhaust pipe. Degradation furnace flue gas was introduced to the municipal solid waste incinerator economiser, and then co-processed in the air pollution control system. The degradation furnace released relatively large amounts of cadmium, lead and polychlorinated dibenzo- p-dioxins and dibenzofurans compared with the municipal solid waste incinerator, but the amounts emitted to the atmosphere did not exceed the Chinese national emission limits. Thermal degradation can therefore be used as a polychlorinated dibenzo- p-dioxin and dibenzofuran abatement method for municipal solid waste incinerator source in China.


Asunto(s)
Contaminación del Aire/prevención & control , Ceniza del Carbón/análisis , Dibenzofuranos Policlorados/química , Incineración/métodos , Dibenzodioxinas Policloradas/química , Contaminantes Atmosféricos/química , Contaminación del Aire/análisis , China , Ceniza del Carbón/química , Incineración/instrumentación , Eliminación de Residuos/instrumentación , Eliminación de Residuos/métodos , Residuos Sólidos
4.
Waste Manag ; 61: 337-344, 2017 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-27998676

RESUMEN

A field study and theoretical calculations on the profile and formation mechanism of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) from two cement kilns co-incinerating municipal solid waste and sewage sludge were performed, and the PCDFs were mainly focused. The back-end areas of the cement kilns were identified to be the major sites of PCDD/F formation according to their distributions in particulate samples from different process stages. The proportions of tetra- to hexa-chlorinated dibenzofurans (∑Cl4-6CDFs) at the kiln back-end areas were in the range of 50-80% of the total PCDD/Fs in mass concentrations and 62-87% in toxic equivalent concentrations. These results indicated that ∑Cl4-6CDFs are the dominant homologs that should be the focus for reducing PCDD/F emissions in cement kilns that co-incinerate municipal solid waste and sewage sludge. It is speculated that the low contents of oxygen and copper compounds, as well as the alkaline conditions, may contribute to the dominance of ∑Cl4-6CDFs in the PCDD/Fs formed. Chlorination was assumed to be the mechanism of formation of PCDFs. The results from model predictions and thermodynamic calculations used to test this assumption were consistent with the PCDF profiles observed from the field study.


Asunto(s)
Dibenzofuranos Policlorados/química , Incineración/métodos , Dibenzodioxinas Policloradas/química , Aguas del Alcantarillado , Residuos Sólidos , Materiales de Construcción , Diseño de Equipo , Incineración/instrumentación , Modelos Químicos , Aguas del Alcantarillado/química
5.
Waste Manag ; 61: 608-616, 2017 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-27876291

RESUMEN

In England and Wales planning regulations require local governments to treat waste near its source. This policy principle alongside regional self-sufficiency and the logistical advantages of minimising distances for waste treatment mean that energy from waste incinerators have been built close to, or even within urban conurbations. There is a clear policy and research need to balance the benefits of energy production from waste incinerators against the negative externalities experienced by local residents. However, the monetary costs of nuisance emissions from incinerators are not immediately apparent. This study uses the Hedonic Pricing Method to estimate the monetary value of impacts associated with three incinerators in England. Once operational, the impact of the incinerators on local house prices ranged from approximately 0.4% to 1.3% of the mean house price for the respective areas. Each of the incinerators studied had been sited on previously industrialised land to minimise overall impact. To an extent this was achieved and results support the effectiveness of spatial planning strategies to reduce the impact on residents. However, negative impacts occurred in areas further afield from the incinerator, suggesting that more can be done to minimise the impacts of incinerators. The results also suggest that in some case the incinerator increased the value of houses within a specified distance of incinerators under specific circumstances, which requires further investigation.


Asunto(s)
Incineración/economía , Costos y Análisis de Costo , Inglaterra , Exposición a Riesgos Ambientales , Incineración/instrumentación
6.
Regul Toxicol Pharmacol ; 80: 164-72, 2016 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-27321060

RESUMEN

A prior report demonstrated an unacceptably low level of accuracy in silica analytical testing, with a general negative bias (i.e., underreporting) although other inaccuracies included false-positive results when analyzing blank filters. The possible bias may have been due to the loss of sample during shipping and or sample preparation. We report on a follow-up study that was designed to mimic the original study, but in which sources of variability were evaluated. We found no effect on silica recoveries due to shipping and confirmed the prior study results that the muffle furnace ashing process led to low overall recoveries (49-104%), depending on the adherence to the recommended preparation method. Plasma ashing recoveries ranged from 89 to 108%. Our results suggest that muffle-furnace ashing using a crucible should be restricted. More broadly, however, muffle-furnace ashing is only one source of analytical error that contributes to the relatively poor overall performance revealed by Cox et al. Whatever the case, OSHA should ensure that its proposed requirements to improve laboratory performance will actually lead to the discovery and correction of all major sources of error by participating laboratories. This is particularly important in light of OSHA's proposed reduction in the PEL and action level proposed by OSHA.


Asunto(s)
Monitoreo del Ambiente/instrumentación , Incineración/instrumentación , Material Particulado/análisis , Dióxido de Silicio/análisis , Cristalización , Monitoreo del Ambiente/métodos , Diseño de Equipo , Calor , Humanos , Exposición por Inhalación/efectos adversos , Modelos Estadísticos , Exposición Profesional/efectos adversos , Salud Laboral , Material Particulado/efectos adversos , Reproducibilidad de los Resultados , Medición de Riesgo , Dióxido de Silicio/efectos adversos
7.
Waste Manag ; 49: 287-303, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26764134

RESUMEN

The dehalogenation measurements could be carried out with the decomposition of plastic wastes simultaneously or successively. This paper reviewed the progresses in dehalogenation followed by thermochemical conversion of plastic-containing wastes for clean energy production. The pre-treatment method of MCT or HTT can eliminate the halogen in plastic wastes. The additives such as alkali-based metal oxides (e.g., CaO, NaOH), iron powders and minerals (e.g., quartz) can work as reaction mediums and accelerators with the objective of enhancing the mechanochemical reaction. The dehalogenation of waste plastics could be achieved by co-grinding with sustainable additives such as bio-wastes (e.g., rice husk), recyclable minerals (e.g., red mud) via MCT for solid fuels production. Interestingly, the solid fuel properties (e.g., particle size) could be significantly improved by HTT in addition with lignocellulosic biomass. Furthermore, the halogenated compounds in downstream thermal process could be eliminated by using catalysts and adsorbents. Most dehalogenation of plastic wastes primarily focuses on the transformation of organic halogen into inorganic halogen in terms of halogen hydrides or salts. The integrated process of MCT or HTT with the catalytic thermal decomposition is a promising way for clean energy production. The low-cost additives (e.g., red mud) used in the pre-treatment by MCT or HTT lead to a considerable synergistic effects including catalytic effect contributing to the follow-up thermal decomposition.


Asunto(s)
Fuentes Generadoras de Energía , Halogenación , Incineración , Plásticos/química , Eliminación de Residuos , Residuos Sólidos/análisis , Incineración/instrumentación , Eliminación de Residuos/instrumentación
8.
Waste Manag ; 49: 272-286, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26750870

RESUMEN

This work presents the effect of the simulated sizes of Municipal Solid Waste (MSW) on the combustion process in a fixed bed experimentally and numerically. The effect of temperature, gas emissions, flame front velocity and process rate are discussed for three different sizes of MSW: 10, 30, and 50 mm. The study found that for the operating conditions of the current model, when the diameter of particles is decreased, the bulk density of the material is increased, resulting in a decrease of convective heat transfer as well as combustion speed. As the diameter size of the material particles increase, the height of the post-combustion zone is increased, while the temperature in a high temperature area is decreased, due to the decrease in the material's bulk density and the excessive increase in porosity. Results also show that the average emission concentration of CO and CO2 decreases gradually with an increase in the particle diameter size.


Asunto(s)
Incineración/métodos , Residuos Sólidos/análisis , Fuentes Generadoras de Energía , Hidrodinámica , Incineración/instrumentación , Modelos Teóricos , Tamaño de la Partícula , Eliminación de Residuos/instrumentación
9.
Waste Manag Res ; 34(2): 139-47, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26608897

RESUMEN

Deposits in municipal waste incinerators are very inhomogeneous in structure and constitution. They cause corrosion and reduce the efficiency, so they need to be removed frequently. Among other systems, operators use water cannons for the deposit removal. Two different removal mechanisms of water-cannon cleaning are suggested: A direct shattering of the deposit by the impact of the water jet, as well as the cracking caused by thermal stresses where droplets cool the deposits. As the contribution of each of the aforementioned mechanisms to the overall cleaning efficiency is unknown, we performed empirical investigations to determine the dominating effect. In a first experimental setup focusing on thermal stress, cold droplets were applied onto hot deposits taken from a waste incinerator. Results showed that the cleaning effect strongly depends on the deposit thickness and structure, so that the deposits could be categorised in three different groups. A second measurement campaign focused on the influence of deposit material, deposit temperature and water jet momentum. It could be shown that both deposit material and temperature have a significant effect on the cleaning efficiency, whereas an increase in water jet momentum only led to modest improvements. The combination of these two parameter studies implies that the influence of the thermal stress outweighs that of the momentum. This knowledge is applicable to the cleaning setup by increasing the temperature gradient.


Asunto(s)
Incineración/métodos , Agua , Incineración/instrumentación
10.
Chemosphere ; 145: 119-24, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26688247

RESUMEN

Municipal solid waste incineration (MSWI) is generally considered as a well-controlled source of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), in brief dioxins. Start-up conditions continue, however, to be problematic. A self-developed continuous sampler was specially designed and built to fulfill the various sampling criteria of U.S. EPA Method 23 and monitor the trends of dioxins emissions during diverse operating conditions. In the MSWI plant investigated, a 98.1% TEQ PCDD/F removal efficiency was achieved in normal operation using activated carbon injection + bag filtration (ACI + BF) and the corresponding PCDD/F emission remains well below the standard set by Taiwan EPA (0.1 ng I-TEQ/Nm(3) @ 11% O2). During start-up, however, continuous sampling indicates that this limit value is reached only after 12 and 9 days, respectively for the 1st (2011) and 2nd test campaign (2012). Only 15 days after start-up the PCDD/F emissions shrunk to the levels typically measured during normal operation. The PCDD/F emissions from the 1st and 2nd continuous sampling campaigns were 5.4 and 5.5 mg I-TEQ, respectively. Short-term PCDD/F sampling such as the U.S. EPA Method 23 is less adapted to monitor these transient PCDD/F emissions representatively and accurately, due to a steady decrease of PCDD/F emissions after start-up. This self-developed continuous sampler effectively enhances the ease and reliability of emission data collecting during transient conditions of MSWI.


Asunto(s)
Contaminantes Atmosféricos/análisis , Benzofuranos/análisis , Monitoreo del Ambiente/métodos , Incineración/métodos , Dibenzodioxinas Policloradas/análogos & derivados , Residuos Sólidos/análisis , Carbón Orgánico/química , Dibenzofuranos Policlorados , Monitoreo del Ambiente/instrumentación , Diseño de Equipo , Filtración , Incineración/instrumentación , Dibenzodioxinas Policloradas/análisis , Taiwán
11.
Environ Technol ; 37(3): 399-406, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-26226945

RESUMEN

The purpose of this paper is to investigate the characteristics of fly and bottom ashes sampled from both fluidized bed (FB) and mass-burning (MB) municipal solid waste incinerators (MSWIs), respectively. Fly ashes from different locations at FB and MB MSWIs equipped with a cyclone, a semi-dry scrubber, and a bag filter as air pollution control devices were examined to provide the baseline information between physicochemical properties and leaching ability. Experimental results of leachability indicated that the bag filter fly ash (FB-FA(B)) from the FB incinerator meets Taiwan regulatory standards set through the toxicity characteristic leaching procedure. X-ray diffraction results revealed the presence of Cr5O12 and Pb2O3 in the cyclone fly ash (MB-FA(C)) and bag filter fly ash (MB-FA(B)), respectively, from the MB incinerator. To observe lead incorporation mechanism, mixture of simulate lead-laden waste with bed material were fired between 600 °C and 900 °C in a laboratory scale FB reactor. The results clearly demonstrate a substantial decrease in lead leaching ratio for products with an appropriate temperature. The concentration of Pb in the MB-FA(B) was 250 times that in the FB-FA(B), suggesting that incineration of MSW in FB is a good strategy for stabilizing hazardous metals.


Asunto(s)
Contaminantes Atmosféricos/análisis , Contaminación del Aire/análisis , Ceniza del Carbón/análisis , Incineración/métodos , Residuos Sólidos/análisis , Contaminantes Atmosféricos/química , Ceniza del Carbón/química , Incineración/instrumentación , Óxidos
12.
Environ Sci Pollut Res Int ; 23(5): 4585-93, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26520096

RESUMEN

Separation between primary and secondary sludge treatment could be a valuable solution for sludge management. According to this approach, secondary sludge can be conveniently used in agriculture while primary sludge could be easily dried and incinerated. It follows that some concern may arise from incinerating primary sludge with respect to the current practice to incinerate mixed digested sludge. Incineration of primary and mixed digested municipal sludge was investigated with a lab-scale equipment in terms of emissions of products of incomplete combustion (PICs) during incineration failure modes. PICs can be grouped in three sub-categories, namely aliphatic hydrocarbons (alkanes and alkenes), compounds with a single aromatic ring, and polycyclic aromatic hydrocarbons (PAHs). After-burning temperature was the most important parameter to be controlled in order to minimize emissions of alkanes and alkenes. As for mono-aromatic compounds, benzene and toluene are the most thermally resistant compounds, and in some cases, an after-burning temperature of 1100 °C was not enough to get the complete destruction of benzene leading to a residual emission of 18 mg/kgsludge. PAHs showed an opposite trend with respect to aliphatic and mono-aromatic hydrocarbons being the thermal failure mode the main responsible of PIC emissions. A proper oxygen concentration is more important than elevated temperature thus reflecting the high thermal stability of PAHs. Overall, obtained results, even though obtained under flameless conditions that are different from those of the industrial plants, demonstrated that separation of primary and secondary sludge does not pose any drawbacks or concern regarding primary sludge being disposed of by incineration even though it is more contaminated than mixed digested sludge in terms of organic pollutants.


Asunto(s)
Incineración , Aguas del Alcantarillado , Calor , Hidrocarburos Aromáticos/química , Incineración/instrumentación , Hidrocarburos Policíclicos Aromáticos/química , Aguas del Alcantarillado/química
13.
J Environ Manage ; 162: 139-47, 2015 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-26241929

RESUMEN

This paper presents the results of a study of an experimental system with thermal treatment (incineration) of medical waste conducted at a large complex of hospital facilities. The studies were conducted for a period of one month. The processing system was analysed in terms of the energy, environmental and economic aspects. A rotary combustion chamber was designed and built with the strictly assumed length to inner diameter ratio of 4:1. In terms of energy, the temperature distribution was tested in the rotary kiln, secondary combustion (afterburner) chamber and heat recovery system. Calorific value of medical waste was 25.0 MJ/kg and the thermal efficiency of the entire system equalled 66.8%. Next, measurements of the pollutant emissions into the atmosphere were performed. Due to the nature of the disposed waste, particular attention was paid to the one-minute average values of carbon oxide and volatile organic compounds as well as hydrochloride, hydrogen fluoride, sulphur dioxide and total dust. Maximum content of non-oxidized organic compounds in slag and bottom ash were also verified during the analyses. The best rotary speed for the combustion chamber was selected to obtain proper afterburning of the bottom slag. Total organic carbon content was 2.9%. The test results were used to determine the basic economic indicators of the test system for evaluating the profitability of its construction. Simple payback time (SPB) for capital expenditures on the implementation of the project was 4 years.


Asunto(s)
Dióxido de Carbono/análisis , Incineración/instrumentación , Eliminación de Residuos Sanitarios/instrumentación , Eliminación de Residuos Sanitarios/métodos , Contaminantes Atmosféricos/análisis , Ceniza del Carbón , Ambiente , Diseño de Equipo , Hospitales , Incineración/economía , Incineración/métodos , Residuos Sanitarios , Eliminación de Residuos Sanitarios/economía , Compuestos Orgánicos/análisis , Temperatura , Compuestos Orgánicos Volátiles/análisis
15.
Waste Manag Res ; 33(6): 561-9, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-26060234

RESUMEN

The present work conducts a preliminary techno-economic feasibility study for a single municipal solid waste mass burning to an electricity plant for the total municipal solid waste potential of the Region of Eastern Macedonia - Thrace, in Greece. For a certain applied and highly efficient technology and an installed capacity of 400,000 t of municipal solid waste per year, the available electrical power to grid would be approximately 260 GWh per year (overall plant efficiency 20.5% of the lower heating value). The investment for such a plant was estimated at €200m. Taking into account that 37.9% of the municipal solid waste lower heating value can be attributed to their renewable fractions, and Greek Law 3851/2010, which transposes Directive 2009/28/EC for Renewable Energy Sources, the price of the generated electricity was calculated at €53.19/MWhe. Under these conditions, the economic feasibility of such an investment depends crucially on the imposed gate fees. Thus, in the gate fee range of 50-110 € t(-1), the internal rate of return increases from 5% to above 15%, whereas the corresponding pay-out time periods decrease from 11 to about 4 years.


Asunto(s)
Fuentes Generadoras de Energía/economía , Incineración/economía , Incineración/instrumentación , Residuos Sólidos/análisis , Estudios de Factibilidad , Grecia , Centrales Eléctricas/economía , Centrales Eléctricas/instrumentación
16.
Environ Technol ; 36(22): 2903-10, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26061904

RESUMEN

This study characterizes the combustion of paper and sewage sludge in a pilot-scale fluidized bed. The highest temperature during combustion within the system was found at the surface of the fluidized bed. Paper sludge containing roughly 59.8% water was burned without auxiliary fuel, but auxiliary fuel was required to incinerate the sewage sludge, which contained about 79.3% water. The stability of operation was monitored based on the average pressure and the standard deviation of pressure fluctuations. The average pressure at the surface of the fluidized bed decreased as the sludge feed rate increased. However, the standard deviation of pressure fluctuations increased as the sludge feed rate increased. Finally, carbon monoxide (CO) emissions decreased as oxygen content increased in the flue gas, and nitrogen oxide (NOx) emissions were also tied with oxygen content.


Asunto(s)
Incineración/métodos , Papel , Eliminación de Residuos/métodos , Aguas del Alcantarillado/química , Monóxido de Carbono/química , Diseño de Equipo , Calor , Incineración/instrumentación , Oxígeno/química , Proyectos Piloto , Presión , Eliminación de Residuos/instrumentación
17.
Waste Manag ; 43: 283-92, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-26025583

RESUMEN

Accelerated carbonation of alkaline wastes including municipal solid waste incinerator bottom ash (MSWI-BA) and the cold-rolling wastewater (CRW) was investigated for carbon dioxide (CO2) fixation under different operating conditions, i.e., reaction time, CO2 concentration, liquid-to-solid ratio, particle size, and CO2 flow rate. The MSWI-BA before and after carbonation process were analyzed by the thermogravimetry and differential scanning calorimetry, X-ray diffraction, and scanning electron microscopy equipped with energy dispersive X-ray spectroscopy. The MSWI-BA exhibits a high carbonation conversion of 90.7%, corresponding to a CO2 fixation capacity of 102g perkg of ash. Meanwhile, the carbonation kinetics was evaluated by the shrinking core model. In addition, the effect of different operating parameters on carbonation conversion of MSWI-BA was statistically evaluated by response surface methodology (RSM) using experimental data to predict the maximum carbonation conversion. Furthermore, the amount of CO2 reduction and energy consumption for operating the proposed process in refuse incinerator were estimated. Capsule abstract: CO2 fixation process by alkaline wastes including bottom ash and cold-rolling wastewater was developed, which should be a viable method due to high conversion.


Asunto(s)
Dióxido de Carbono/química , Ceniza del Carbón/química , Incineración/métodos , Aguas Residuales/química , Carbono/química , Carbonatos/química , Incineración/economía , Incineración/instrumentación , Cinética , Microscopía Electrónica de Rastreo , Modelos Teóricos , Termogravimetría , Difracción de Rayos X
18.
J Air Waste Manag Assoc ; 65(4): 413-22, 2015 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-25947211

RESUMEN

UNLABELLED: Recently, numerical and experimental studies have been conducted to develop a moderate or intense low-oxygen dilution (MILD) combustion technology for solid fuels. The study results demonstrated that intense recirculation inside the furnace by high-momentum air is a key parameter to achieve the MILD combustion of solid fuels. However, the high-velocity air requires a significant amount of electricity consumption. A cyclone-type MILD combustor was therefore designed and constructed in the authors' laboratory to improve the recirculation inside the combustor. The laboratory-scale tests yielded promising results for the MILD combustion of dried sewage sludge. To achieve pilot-scale MILD combustion of dried sludge in this study, the effects of geometric parameters such as the venturi tube configuration, the air injection location, and the air nozzle diameter were investigated. With the optimized geometric and operational conditions, the pilot-scale cyclone combustor demonstrated successful MILD combustion of dried sludge at a rate of 75 kg/hr with an excess air ratio of 1.05. IMPLICATIONS: A horizontal cyclone combustor with recirculation demonstrated moderate or intense low-oxygen dilution (MILD) combustion of dried sewage sludge at a rate of 75 kg/hr. Optimizing only geometric and operational conditions of the combustor reduced nitrogen oxide (NOx) emissions to less than 75 ppm. Because the operating cost of the MILD combustor is much lower than that of the selective catalytic reduction (SCR) applied to the conventional combustor, MILD combustion technology with the cyclone type furnace is an eligible option for reducing NOx emissions from the combustion of dried sewage sludge.


Asunto(s)
Incineración/instrumentación , Óxidos de Nitrógeno/química , Aguas del Alcantarillado/química , Aire , Movimientos del Aire , Incineración/métodos , Proyectos Piloto , Instalaciones de Eliminación de Residuos
19.
Anal Bioanal Chem ; 407(20): 5911-22, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25711989

RESUMEN

In this study, we produced a class of diffusion flame soot particles with varying chemical and physical properties by using the mini-Combustion Aerosol STandard (CAST) and applying varying oxidant gas flow rates under constant propane, quenching, and dilution gas supply. We varied the soot properties by using the following fuel-to-air equivalence ratios (Φ): 1.13, 1.09, 1.04, 1.00, 0.96, and 0.89. Within this Φ range, we observed drastic changes in the physical and chemical properties of the soot. Oxidant-rich flames (Φ < 1) were characterized by larger particle size, lower particle number concentration, higher black carbon (BC) concentration, lower brown carbon BrC.[BC](-1) than fuel-rich flames (Φ > 1). To investigate the polycyclic aromatic hydrocarbons (PAH) formation online, we developed a new method for quantification by using the one (13)C-containing doubly charged PAH ion in a high-resolution time-of-flight aerosol mass spectrometry (HR-ToF-AMS). The time-resolved concentration showed that the larger PAHs prevailed in the fuel-rich flames and diminished in the oxidant-rich flames. By comparison with the offline in situ derivatization-thermal-desorption gas-chromatography time-of-flight mass spectrometry (IDTD-GC-ToF-MS), we found that the concentration by using the HR-ToF-AMS was underestimated, especially for lower mass PAHs (C14-C18) in the fuel-rich flames possibly due to size limitation and degradation of semi-volatile species under high vacuum and desorption temperature in the latter. For oxidant-rich flames, the large PAHs (C20 and C22) were detected in the HR-ToF-AMS while it was not possible in IDTD-GC-ToF-MS due to matrix effect. The PAH formation was discussed based on the combination of our results and with respect to Φ settings.


Asunto(s)
Contaminantes Atmosféricos/análisis , Incineración/instrumentación , Hidrocarburos Policíclicos Aromáticos/análisis , Hollín/análisis , Aerosoles/análisis , Diseño de Equipo , Espectrometría de Masas , Tamaño de la Partícula
20.
Environ Sci Pollut Res Int ; 22(2): 1207-14, 2015 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-25124474

RESUMEN

Distribution of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) in the fly ash and atmospheric air of one medical waste incinerator (MWI) and one industrial hazardous waste incinerator (IHWI) plants were characterized. The PCDD/F concentrations of the stack gas (fly ash) produced from MWI and IHWI were 17.7 and 0.7 ng international toxic equivalent (I-TEQ)/Nm(3) (4.1 and 2.5 ng I-TEQ/g), respectively. For workplace air, the total concentrations of PCDD/Fs were 11.32 and 0.28 pg I-TEQ/Nm(3) (819.5 and 15.3 pg/Nm(3)). We assumed that the large differences of PCDD/F concentrations in workplace air were due to the differences in chlorine content of the waste, combustion conditions, and other contamination sources. With respect to the homologue profiles, the concentrations of PCDFs decreased with the increase of the substituted chlorine number for each site. Among all of the PCDD/F congeners, 2,3,4,7,8-PeCDF was the most important contributor to the I-TEQ value accounting for ca. 43 % of two sites. The gas/particle partition of PCDD/Fs in the atmosphere of the workplace in the MWI was also investigated, indicating that PCDD/Fs were more associated in the particle phase, especially for the higher chlorinated ones. Moreover, the ratio of the I-TEQ values in particle and gas phase of workplace air was 11.0. At last, the relationship between the distribution of PCDD/Fs in the workplace air and that from stack gas and fly ash was also analyzed and discussed. The high correlation coefficient might be a sign for diffuse gas emissions at transient periods of fumes escaping from the incinerator.


Asunto(s)
Aire/análisis , Benzofuranos/análisis , Ceniza del Carbón/química , Monitoreo del Ambiente , Residuos Peligrosos , Incineración , Dibenzodioxinas Policloradas/análogos & derivados , Contaminantes Atmosféricos/análisis , Contaminantes Atmosféricos/química , Benzofuranos/química , China , Dibenzofuranos Policlorados , Gases/química , Incineración/instrumentación , Residuos Sanitarios , Dibenzodioxinas Policloradas/análisis
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