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Characterization of Emissions from Fuel Combustion

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A special issue of Processes (ISSN 2227-9717). This special issue belongs to the section "Energy Systems".

Deadline for manuscript submissions: closed (30 June 2022) | Viewed by 16180

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Special Issue Editors

Dr. Hans-Joachim Gehrmann

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Guest Editor

Department Combustion- and Particle Technology, Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen, Germany
Interests: NOx-reduction by oscillating combustion; development of suitable processes for the energetic recovery for carbon reinforced fibres, e.g., metallurgical processes or molten-carbonate fuel cell; combustion of ammonia; release of PFAS from combustion processes

Prof. Dr. Yeong-Jin Chung

E-Mail Website
Guest Editor

Department of Fire Protection Engineering, Kangwon National University, Gangwon-do 24549, Korea
Interests: combustion; hazardous materials safety; fire risk assessment

Special Issue Information

Dear Colleagues,

Even with the “Green Deal” and the reduction of fossil energy sources, there will be an issue with “emissions”: emissions from the conventional combustion of hydrogen cause NOx; NOx formation increases when supplying ammonia as a carbon-free fuel to a combustor, due to the nitrogen in the fuel. My favourite research on this topic, among others, is the capability to reduce NOx emissions by a primary measure—the oscillating supply of fuel and/or an oxidiser into the combustion zone. This topic is not new, but so far, adapted to gaseous fuels and not to solid fuels. My team and I found that for pulverized fuel boilers as well as for grate incinerators, an adaption of this process is possible—with reduction rates of about 50%. Actually, we have a research project to find solutions for the combustion of wastes from the furniture industry to provide heat.

Are there any doubts about environmental friendly combustors for woody biomass?

First answer: surely not, but have a second look at emissions! Beside NOx, particulate matter is a topic for us. We focus on the reduction of particulate matter with electronic precipitators (ESP) and look for their impact on lung cells.

Beside NOx from combustion processes, other emissions from substances that we all use in our casual clothing are an important focus: polyfluorinated substances are spread all over the world. They could be found in the water that we drink, the soil that we use for agriculture and the air that we breathe. Since PTFE was invented and has been produced for 80 years, this product is widely used in flue gas treatment plants in baghouse filters, as material for tubes or to protect pans. By the end of their lifetime, PTFE products become waste and have to be treated in an environmentally friendly way. Nevertheless, more than 4000 species are known, and in some cases, the quality of drinking water has to be improved by activated carbon filters to adsorb the polyfluorinated acids (PFOA). In a joint research project with GORE company, we investigated the behaviour of PTFE during combustion and analyzed the flue gas composition after the boiler, in order to monitor the release of PFAS. We are focussing on research which develops methods to analyze PFAS in flue gases and address questions regarding the destruction efficiencies of PFAS in thermo-chemical processes and the long-term emissions resulting in landfilling.

Another topic that we are looking at is: How to proceed with wastes from wind turbine blades after their lifetime is over? In particular, carbon-reinforced fibres, used widely not only in wind mills but in cars and air crafts, may generate small fibres, while they are dismantelled and mechanically pretreated for combustion. During these processes, fibres with a WHO-geometry that can penetrate deep into the lungs and potentially cause diseases may be released into the environment.

Briefly, emissions are an issue in all described cases.

Topics include, but are not limited to:

Reduction of NOx by primary and secondary measures for the combustion of “advanced fuels” like hydrogen, ammonia
Release, analytics, sampling of PFAS in flue gases from combustion of fluorinated wastes, balancing the process (fluorine)
Strategies to avoid emissions from PFAS into the environment
Processes for energetic recovery and feedstock recycling of carbon reinforced fibres: analytics, balances and strategies

Dr. Hans-Joachim Gehrmann
Prof. Dr. Yeong-Jin Chung
Guest Editors

Manuscript Submission Information

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Keywords

Briefly, emissions are an issue in all described cases.

Topics include, but are not limited to:

Reduction of NOx by primary and secondary measures for the combustion of “advanced fuels” like hydrogen, ammonia
Release, analytics, sampling of PFAS in flue gases from combustion of fluorinated wastes, balancing the process (fluorine)
Strategies to avoid emissions from PFAS into the environment
Processes for energetic recovery and feedstock recycling of carbon reinforced fibres: analytics, balances and strategies

Published Papers (5 papers)

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Research

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14 pages, 5483 KiB

Open AccessArticle

Fundamental Study on Hydrogen Low-NOx Combustion Using Exhaust Gas Self-Recirculation

by Kenta Kikuchi, Tsukasa Hori and Fumiteru Akamatsu

Processes 2022, 10(1), 130; https://doi.org/10.3390/pr10010130 - 09 Jan 2022

Cited by 12 | Viewed by 4905

Abstract

Hydrogen is expected to be a next-generation energy source that does not emit carbon dioxide, but when used as a fuel, the issue is the increase in the amount of NOx that is caused by the increase in flame temperature. In this study, we experimentally investigated NOx emissions rate when hydrogen was burned in a hydrocarbon gas burner, which is used in a wide temperature range. As a result of the experiments, the amount of NOx when burning hydrogen in a nozzle mixed burner was twice as high as when burning city gas. However, by increasing the flow velocity of the combustion air, the amount of NOx could be reduced. In addition, by reducing the number of combustion air nozzles rather than decreasing the diameter of the air nozzles, a larger recirculation flow could be formed into the furnace, and the amount of NOx could be reduced by up to 51%. Furthermore, the amount of exhaust gas recirculation was estimated from the reduction rate of NOx, and the validity was confirmed by the relationship between adiabatic flame temperature and NOx calculated from the equilibrium calculation by chemical kinetics simulator software. Full article

(This article belongs to the Special Issue Characterization of Emissions from Fuel Combustion)

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20 pages, 5105 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Oscillating Combustion—Primary Measure to Reduce Nitrogen Oxide in a Grate Furnace–Experiments and Simulations

by Hans-Joachim Gehrmann, Bo Jaeger, Siegmar Wirtz, Viktor Scherer, Krasimir Aleksandrov, Manuela Hauser, Dieter Stapf, Gregor Pollmeier and Philipp Danz

Processes 2021, 9(12), 2210; https://doi.org/10.3390/pr9122210 - 08 Dec 2021

Cited by 6 | Viewed by 2347

Abstract

The emission from industries and the mobility sector is under strong legal regulations in many countries worldwide. In Germany, the amendment to the 17th BlmSchV (Federal pollution control ordinance), which has been in force for waste incineration plants since 2013, has given rise to a new limit for nitrogen oxides of 150 mg/m³ as the daily mean level from 2019 on. A similar focus is on biomass-fired plants. According to the MCP (medium combustion plant) guideline of the EU, as a consequence, existing plants are required to either increase their consumption of ammonia water for nitrogen oxide reduction (SNCR process) or back fit SCR catalysts as secondary measures, which is a costly procedure. This paper presents a novel two-stage process in which an oscillating supply of secondary air allows nitrogen oxides to be reduced by approx. 50% at a good burnout level, which may obviate the need for secondary measures. Besides experimental investigations in a fixed bed reactor, CFD simulations confirm a high potential for reduction of nitrogen oxides. Together with the company POLZENITH, this process is under development for scale-up in a biomass incineration plant as a next step. Full article

(This article belongs to the Special Issue Characterization of Emissions from Fuel Combustion)

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10 pages, 3507 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Kinetic Behavior of Fabricated CuO/ZrO₂ Oxygen Carriers for Chemical Looping Oxygen Uncoupling

by Young Ku, Chia-Wei Chang, Shr-Han Shiu, Hsuan-Chih Wu and Niels Michiel Moed

Processes 2021, 9(12), 2156; https://doi.org/10.3390/pr9122156 - 29 Nov 2021

Cited by 1 | Viewed by 1095

Abstract

Chemical looping with oxygen uncoupling (CLOU) is an innovative alternative to conventional combustion. CuO/ZrO₂ oxygen carriers were tested in this system for their effectiveness and resilience. Cupric oxide (CuO) was demonstrated to be a reliable oxygen carrier for oxygen-uncoupling with consistent recyclability even after 50 redox cycles in a thermogravimetric analyzer (TGA). The reduction of CuO to generate Cu₂O and oxygen was observed to be improved markedly for experiments operated at higher temperatures; however, the oxidation of Cu₂O by air to generate CuO was hindered for experiments carried out at elevated temperatures. The reduction rate of fabricated CuO/ZrO₂ particles containing 40% CuO was enhanced with increasing temperature and decreased with increasing particle size for experiments operated in a fixed bed reactor. The geometrical contraction and Avrami-Erofe’ev models were demonstrated to be appropriate for describing the reduction and oxidation of CuO/ZrO₂, respectively. The activation energies for the reduction and oxidation were determined to be 250.6 kJ/mol and 57.6 kJ/mol, respectively, based on experimental results in the temperature range between 850 and 1000 °C. Full article

(This article belongs to the Special Issue Characterization of Emissions from Fuel Combustion)

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13 pages, 2670 KiB

Open AccessArticle

Research on Prediction Accuracy of Coal Mine Gas Emission Based on Grey Prediction Model

by Jun Zeng and Qinsheng Li

Processes 2021, 9(7), 1147; https://doi.org/10.3390/pr9071147 - 30 Jun 2021

Cited by 7 | Viewed by 1902

Abstract

In order to achieve the accuracy of gas emission prediction for different workplaces in coal mines, three coal mining workings and four intake and return air roadway of working face in Nantun coal mine were selected for the study. A prediction model of gas emission volume based on the grey prediction model GM (1,1) was established. By comparing the predicted and actual values of gas emission rate at different working face locations, the prediction error of the gray prediction model was calculated, and the applicability and accuracy of the gray prediction method in the prediction of gas gushing out from working faces in coal mines were determined. The results show that the maximum error between the predicted and actual measured values of the gray model is 2.41%, and the minimum value is only 0.07%. There is no significant prediction error over a larger time scale; the overall prediction accuracy is high. It achieves the purpose of accurately predicting the amount of gas gushing from the working face within a short period of time. Consequently, the grey prediction model is of great significance in ensuring the safety production of coal mine working face and promote the safety management of coal mine. Full article

(This article belongs to the Special Issue Characterization of Emissions from Fuel Combustion)

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Review

Jump to: Research

21 pages, 6178 KiB

Open AccessFeature PaperReview

Impact of Residential Real-World Wood Stove Operation on Air Quality concerning PM2.5 Immission

by Julia R. D. Thieringer, Julia Szabadi, Jörg Meyer and Achim Dittler

Processes 2022, 10(3), 545; https://doi.org/10.3390/pr10030545 - 11 Mar 2022

Cited by 2 | Viewed by 5126

Abstract

In Germany, the number of small wood-burning combustion plants was around 11 million in 2020. The PM2.5 immissions caused by the operation of these combustion plants are already about as high as those from traffic exhaust gases. Thus, particulate matter immissions occur not only on busy roads but also in residential areas. Since there are few official measuring stations for PM2.5 in residential areas and suburbs, this study determined PM2.5 concentrations from November 2020 to June 2021 at three stations (urban, suburban, and residential) in the Karlsruhe area. Simultaneous measurements of PM2.5 at the three locations have been implemented to determine short-term (peaks), medium-term, and long-term particulate matter levels and to assign them to sources by observation, considering wind direction. Illustratively, PM2.5 immission levels in January and May 2021 were compared in this paper. The comparison of the particulate matter immissions measured in the urban and residential area in January revealed that PM2.5 concentration peaks of up to 60 µg/m³ occurred for short periods in the residential area, especially on Fridays and in the evenings, which could be assigned to wood stove operation. In the urban and suburban areas, the number of the immission peaks was lower by 70–80%, and the peak concentrations were also lower by an average of 13–18%. However, the high short-term peaks have no significant impact when calculating the PM2.5 annual average according to the current limit value regulation (39. BImSchV). Full article

(This article belongs to the Special Issue Characterization of Emissions from Fuel Combustion)

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