Numerical prediction of the chemical composition of gas products at biomass combustion and co-combustion in a domestic boiler

In recent years the numerical modelling of biomass combustion has been successfully applied to determine the combustion mechanism and predict its products. In this study the influence of the addition of waste glycerin in biomass wood pellets on the chemical composition of exhaust gases has been investigated. The pellets have been prepared from spruceand pine wood sawdust without and with addition of waste glycerin. The waste glycerol is a undesirable by-product of biodiesel transesterification at oil manufacturing. The produced pellets were being burned in the 10 kW domestic boiler adapted to wood pellets combustion. The possibilities of pollutants generation (CO2, CO, NOx SOx and compounds containing chlorine) in the exhaust gases coming from the boiler were numerically calculated using the latest version of CHEMKIN-PRO software, introduced by the American company Reaction Design. The results of the calculations correspond to the data obtained on a real object, in particular: combustion temperature, gas pressure, residence time of fuel in the burner, air flow, fuel consumption, as well as elementary composition of fuel supplied into the boiler. The proposed method of predicting the chemical composition of exhaust gases allows proper control of the combustion process and can be considered as an important step in reducing the pollutants (lower emission of NOx, SOx and CO2 neutral) and thus to contribute to the improvement of the environmental quality. In addition, knowledge of the amounts of Clbased compounds produced in combustion process (under given conditions), can serve as an important hint in terms of corrosion prevention of boiler- and chimney steels

Theoretical and experimental analysis of the impact of wood co-combustion, as a reburning fuel, with natural gas on the chemical composition of flue gases

W artykule podjęto problematykę wykorzystania stałych odpadów drzewnych jako paliw reburningowych, w procesie współspalania z gazem ziemnym. Zaproponowana forma spalania stwarza możliwość nie tylko zagospodarowania odpadów przemysłu drzewnego, ale również redukcji zanieczyszczeń, a w szczególności tlenków azotu, ze względu na specyfikę metody reburningu. Ze względu na ograniczone możliwości pomiarowe eksperyment laboratoryjny poszerzono o symulacje numeryczne.The energy utilization of waste fuels of vegetable origin, in particular wood waste, is beneficial not only for economic reasons, but primarily ecological reasons, as demonstrated by the research results obtained. One way of utilizing wood waste for energy purposes is its co- combustion with other fuels, such as natural gas (or coal), in the reburning process, which leads to a reduction in pollution, in particular a reduction in the concentration of nitrogen oxides. A reburning method can be used in much power equipment, both in the power industry, and industry as a whole. Although in the reburning of fuel conventional fuels are mainly used, there are many reasons to use biofuel, because of its reductive properties. The results of this research were very close to experimental, proving the accuracy of the assumptions adopted in the model. The slightly lower NOx concentration value obtained in the model research is the result of the condition of a perfect stirring of the reactants, ie, the main assumptions adopted in the calculation model. Furthermore, numerical simulations provided data that would be impossible in the experiments, namely, the detailed composition of flue gases for different reburning fuel shares. Due to the high concentration of CO, actual measurement in experimental conditions was not possible. The satisfactory research results presented in this article create the need for further experiments using a pressure pulse to increase the intensification of stirring, and thus receive a more effective reduction in nitrogen oxide concentration . However, a more simplified chemical model should also be considered, containing a smaller number of reactions and chemical compounds, whose share in the flue gases is not as large

Prediction of the chemical composition of combustion products in metallurgical heat furnaces with numerical methods use

In this paper the results of numerical calculations of chemical composition of flue gases, produced bycombustion of natural gas, were presented. Calculations were conducted for metallurgical pusher furnace,working in one of the steelworks located in Poland. The chemistry of combustion process was modeled usingthe program CHEMKIN-PRO. Simulations of the chemical composition of flue gas, in various zones of thefurnace, were carried out based on the measurement data collected from the real object

The control of NOx concentration in natural gas combustion process

W artykule podjęto problematykę formowania tlenków azotu w procesie spalania gazu ziemnego przy zmiennej wartości stosunku nadmiaru powietrza i temperatury. Wymienione parametry odgrywają bowiem istotną rolę w powstawaniu NOx, o czym świadczą zaprezentowane wyniki badań oraz liczne publikacje. Kontrola tych parametrów pozwala ograniczyć ilość formowanych tlenków azotu. W ramach badań przeprowadzono eksperyment laboratoryjny oraz obliczenia numeryczne, mające na celu określenie wpływu stosunku nadmiaru powietrza i temperatury na udział NOx w spalinach. Pomiaru stężenia NOx dokonano w piecu elektryczno-gazowym za pomocą analizatora Testo 350. Przeprowadzono też symulacje komputerowe z wykorzystaniem programu CHEMKIN. Otrzymane wyniki badań doświadczalnych i modelowych przedstawiono graficznie oraz dokonano ich analizy porównawczej.Article discusses the problem of nitrogen oxides formation during the natural gas combustion with variable excess air factor and temperature. These parameters play an important role in the NOx formation, as evidenced by present results of research and numerous publications. control of these parameters allows to limit the amount of formed nitrogen oxides. The purpose of this study was to determine the effect of excess air factor and temperature on the part of NOx in the exhaust. Research consisted of conducting laboratory experiments and performing numerical calculations. NOx concentrations were measured in the electric- gas furnace using gas analyzer Testo 350. Furthermore, computer simulations were carried out using the program CHEMKIN. The obtained experimental and model results were presented graphically and there was made a comparative analysis

Energy use of biomass from agricultural production in co-combustion process

W pracy zaproponowano wykorzystanie biomasy z produkcji rolniczej – siana, słomy, łupin słonecznika i orzecha włoskiego oraz całych ziaren słonecznika, dyni i kukurydzy – w procesie współspalania z gazem ziemnym. Eksperyment laboratoryjny przeprowadzono w cylindrycznej komorze grzewczej o średnicy wewnętrznej 0,34 m i sumarycznej długości 3,12 m. Zastosowana w badaniach technologia spalania, zwana reburningiem, pozwala nie tylko zagospodarować ww. biomasę w celach energetycznych, ale również, ze względu na specyfikę tej metody, przynosi korzyści ekologiczne, prowadzi ona bowiem do znacznego zmniejszenia stężenia tlenków azotu w spalinach, co w świetle obowiązujących norm środowiskowych jest działaniem jak najbardziej pożądanym. Metoda reburningu może być stosowana w wielu urządzeniach energetycznych, zarówno w energetyce zawodowej, jak i przemysłowej. Jako paliwa reburningowe używane są głównie paliwa konwencjonalne, jednak istnieje wiele przesłanek, aby zastosować również biomasę, o czym świadczą przedstawione w niniejszej pracy wyniki badań.In this paper the use of biomass from agricultural production, i.e.: hay, straw, husks of sunflower and whole walnuts, as well as seeds of sunflower, pumpkin and corn in co-combustion process with natural gas was proposed. Laboratory experiment was performed in a cylindrical heating chamber with an internal diameter 0.34 m and total length of 3.12 m. The combustion technology applied in research is called reburning. It allows not only for utilization the biomass for energy purposes, but also brings environmental benefits. Due to the specificity of this method, it leads to a significant reduction in the concentration of nitrogen oxides in the flue gas. In the light of current environmental standards it is very desirable action. The reburning method can be used in many energy devices, both in the power industry, as well as industrial energy. As fuel in this process conventional fuels are primarily used. But there are also many reasons for the use of biomass, and as evidenced by the results of research presented in this article

Economic – ecological aspects of energy utilization of landfill biogas

Powszechnie stosowanym sposobem zagospodarowania i unieszkodliwiania odpadów komunalnych w Polsce jest ich składowanie na wysypiskach odpadów. Składowiska stanowią swego rodzaju bioreaktory, w których następuje rozkład substancji organicznej zawartej w masie odpadów. Wynikiem tych procesów jest wydzielanie się biogazu. Powstający na wysypisku gaz może stanowić realne źródło energii; poza tym ujmowanie i odpowiednie wykorzystanie pozwala ograniczyć jego szkodliwy wpływ na stan środowiska naturalnego. Biogaz uchodzi głównie do atmosfery, a gdy brak jest uszczelnienia wysypiska, także do otaczającego gruntu. Polskie wysypiska nie są jeszcze zbyt dobrze przygotowane pod kątem ujmowania biogazu. Wiele z nich pozbawionych jest nadal odpowiednich instalacji i zabezpieczeń. Na szczęście uregulowania prawne w tym zakresie są coraz bardziej rygorystyczne, z korzyścią dla środowiska naturalnego.This paper presents the possibility of landfill gas energy use in the process of combustion and co-combustion. Based on the literature and own research, the analysis of energy suitability of biogas in terms of economical and ecological was carried out. Within the laboratory experiment the measurements of the flue gas during co-combustion of biogas with natural gas were performed. The co-combustion method, due to its characteristics, is classified as the primary methods of nitrogen oxides reduction. The proposed technique of cocombustion is advantageous for NOx reduction, especially in high temperature processes. The synthetic biogas used for testing has similar composition to the landfill gas composition and was a mixture of three components of the following volume shares: CH4 = 50%, N2 = 10%, CO2 = 40%. A laboratory experiment was conducted in a cylindrical quartz chamber. The biogas used in study was introduced into the chamber as an additional fuel, so-called reburning fuel. Conducted experiments have shown that the landfill biogas due to the high calorific value is fully suitable for energy use. In addition, properly performed co-combustion process of landfill gas with conventional fuels, such as natural gas, can substantially affect the reduction of nitrogen oxides emissions

Coal combustion in an oxygen-enriched atmosphere vs pollutants

Obecnie zdecydowana większość państw opiera swój przemysł energetyczny na źródłach nieodnawialnych. Jednak energetycznemu wykorzystaniu zasobów naturalnych towarzyszy emisja szkodliwych produktów spalania. Rosnąca świadomość negatywnego oddziaływania zanieczyszczeń na środowisko, a przede wszystkim na organizm ludzki doprowadziła do wzrastającej aktywności badań w obszarze technologii spalania, które w znacznym stopniu pozwolą na ograniczenie tworzących się zanieczyszczeń. W niniejszym artykule przedstawiono analizę procesu spalania węgla kamiennego w powietrzu wzbogaconym tlenem w eksperymentalnej komorze fluidalnej. Mając na uwadze wymagania dotyczące ochrony środowiska w kwestii ograniczenia emisji zanieczyszczeń szczególną uwagę zwrócono na problematykę formowania szkodliwych produktów spalania węgla. W celu oszacowania składu chemicznego spalin wykorzystano numeryczne modelowanie. Obliczenia wykonano w najnowszej wersji programu CHEMKIN dla reaktora idealnego wymieszania (PSR), opierając je na zmodyfikowanym mechanizmie GRI- Mech 3.0 obejmującym 152 reakcje chemiczne oraz 46 pierwiastków i związków chemicznych. Przeprowadzone obliczenia pozwoliły na ocenę wpływu składu atmosfery gazowej na stężenie: dwutlenku węgla, tlenków siarki, tlenków azotu i tlenku węgla, a także umożliwiły głębsze poznanie mechanizmów tworzenia się poszczególnych zanieczyszczeń. Otrzymane wyniki badań modelowych przedstawiono graficznie oraz dokonano ich analizy. Zaprezentowane wyniki badań dowodzą, że spalanie węgla kamiennego w powietrzu wzbogaconym tlenem prowadzi do wzrostu stężenia CO2 w spalinach, co pozwala na jego ograniczenie w drodze sekwestracji.Presently, the energy industries of the vast majority of countries are based on non- renewable sources. However, the use of natural resources in energy production is connected with the emission of harmful combustion byproducts. Growing awareness of the negative impact of pollution on the environment and above all human health, has led to increasing research in the field of combustion technology, which will allow a significantly reduction in farmed pollutants. This article presents an analysis of the process of oxygen-enriched hard coal combustion in a fluidized bed. Bearing in mind the environmental protection requirements concerning the reduction in the emissions of pollutants, this analysis paid particular attention to the problems of the formation of harmful coal combustion byproducts. In order to estimate the chemical content of fumes, numerical modeling was applied. Calculations were conducted using the latest version of the CHEMKIN program for the Perfectly Stirred Reactor (PSR), based on a modified GRI-Mech 3.0 mechanism including 152 chemical reactions and 46 elements and chemical compounds. The conducted calculations allowed this study to assess the impact of the gas atmosphere’s content on the concentration of carbon dioxide, sulfur oxides, nitric oxides and carbon monoxide, while also allowing for a better understanding of the mechanisms forming respective pollutants. The results obtained in the model tests were represented graphically and analyzed. The research results prove that the coal combustion in oxygen-enriched atmosphere leads to CO2 concentration in flue gas increase, what allows to its reduction by the sequestration

Pyrolysis-Based Municipal Solid Waste Management in Poland—SWOT Analysis

Poland’s management of municipal waste, which amounts to over 13 million tons/year, is not efficient—about 60% of the waste is subjected to recovery processes, about 20% of all municipal waste is converted into energy, and almost 40% is landfilled. The authors of this article recognize the potential of pyrolysis as a method of the thermal processing of waste allowing the potential of the energy contained in the waste to be utilized. Pyrolysis is an economically attractive alternative to incineration, with a significantly lower environmental impact, allowing efficient waste management and the use of pyrolysis by-products in the energy sector (pyrolysis gas), or in the building materials sector (biochar). Despite so many advantages, this method is not employed in Poland. The aim of the paper is to indicate a recommended strategy for the application of pyrolysis in Poland as a method of the thermal processing of municipal solid waste. SWOT (strengths, weaknesses, opportunities, threats) analysis was used as a research method. In the first step, on the basis of the literature review, the factors which may affect the use of pyrolysis in Poland were identified. In the second step, five experts evaluated the weights of those factors and the interactions between them. The products of the weights and interactions allowed, in accordance with SWOT analysis methodology, the most desirable strategy of pyrolysis application in Poland to be determined, which turned out to be an aggressive one. This means that pyrolysis as a thermal waste processing method should be implemented on a large scale in Poland to improve the indicators of municipal waste management

The chemical mechanism of SOx formation and elimination in coal combustion process

W artykule przybliżono istotę procesu spalania paliw stałych. Na przykładzie węgla zaprezentowano mechanizm powstawania SOx, a także metody usuwania tlenków siarki ze spalin. Pokazano też praktyczne rozwiązania ograniczania emisji SOx oraz korzyści płynące z wykorzystania metod numerycznych do przewidywania i ograniczania emisji SOx i NOx z procesu energetycznego spalania węgla.This paper outlines the nature of the combustion process of solid fuels. Using coal for example, the mechanism of SOx formation was presented, as well as methods of elimination of sulphur oxides from exhaust fumes. Also, the paper discusses the practical solutions for reducing SOx emissions and the benefits of employing numerical methods for predicting and reducing SOx and NOx emissions from coal combustion for energy generation purposes

Prediction of grain size distribution in biomass grinding product

Przedstawiono możliwość zastosowania prawa podziału Maxwella-Boltzmana do prognozowania uziarnienia produktu rozdrobnienia biomasy. We wcześniejszych badaniach oznaczano skład ziarnowy produktu rozdrobnienia swobodnego substancji kruchych, takich jak węgiel, piasek kwarcowy czy kulki szklane. W tej pracy do badań doświadczalnych wykorzystano odpady drewniane, które poddano procesowi rozdrabniania poprzez cięcie w młynku nożowym. Prędkość obwodowa młynka wynosiła 3000 obr/min. Do analizy ziarnowej wykorzystano analizator laserowy IPS (Infrared Particle Sizer) KμK. Uśrednione wyniki laboratoryjnych analiz ziarnowych porównano z wynikami obliczeń analitycznych składu ziarnowego wg przedstawionego algorytmu uzyskując istotną zbieżność.Possibility of application of the Maxwell-Boltzmann distribution law in the prediction of size distribution in biomass grinding product is presented in the paper. In earlier studies, the size distribution was determined for the free fragmentation of brittle substances such as coal, silica sand or glass beads. Current experimental studies used wood wastes which underwent the mill grinding by cutting knife. The mill peripheral speed was fixed at 3000 rpm. The laser analyser IPS (Infrared Particle Sizer) KμK was used in grain analysis. The mean values of laboratory grain analyzes were compared with those obtained via analytical calculations of particle size distribution according to the presented algorithm. A significant convergence was obtained