The primary methods of reducing nitrogen oxides, despite the development of more advanced technologies, will continue to be the basis for NOx reduction. This paper presents the results of multivariate numerical studies on the impact of air staging on the flue gas temperature and composition, as well as on NOx emissions in a OP 230 boiler furnace. A numerical model of the furnace and the platen superheater was validated based on measurements using a 0-dimensional model of the boiler. Numerical simulations were performed using the ANSYS Workbench package. It is shown that changes in the distribution of air to OFA nozzles, the angle of the air outflow from the nozzles and the nozzle location involve a change in the flue gas temperature and in the volume of NOx and CO emissions at the furnace outlet.
Results of the study examining carbon monoxide and nitric oxide concentrations while burning different types of agricultural biomass: coffee husk pellets alone or in combination with wheat straw pellets and cherry stones, sewage sludge pellets, corn stover briquettes and a mixture of rye straw briquettes and miscanthus briquettes were presented. The combustion was performed in a 50 kW boiler type Biowarmer with a cast-iron moving step grate. The temperature in the combustion chamber did not exceed 800 ◦C. For all biomass types, only brittle slag was generated in the furnace, which was easily broken by a reciprocating movement of the grate. Carbon monoxide concentration in the flue gas except for the case of sewage sludge pellet firing did not exceed the permitted value of 3000 mg/m3 and nitric oxide concentration 515 mg/m3, both presented for 10% O2 concentration in the flue gas based in dry gas. Hydrocarbon concentrations for all test runs were close to zero.
In the paper the influence of moisture content of wood on the heat losses and thermal efficiency of a boiler is analysed. The moisture content of wood has a negative effect, especially on flue gas loss. The mathematical dependence of the thermal efficiency of a boiler is presented for the following boundary conditions: the moisture content of wood 10–60%, range of temperatures of emitted flue gases from the boiler into the atmosphere 120–200 C, the emissions meeting the emission standards: carbon monoxide 250 mgm-3, fly ash 50 mgm-3 and the heat power range 30–100%.
Using renewable energy sources has a great potential for industry and households now and also in the future. Biomass plays an important role in reducing fossil fuel consumption. However, biomass is divided into phytomass, dendromass and zoomass, it offers us the possibility of using agricultural waste – phytomass. Phytomass is compared with biomass economically available, but combustion properties of phytomass are worse. In our work we decided use different ratios of phytomass and dendromass for better combustion process. Dendromass without addition of phytomass was combusted for comparison. Phytomass with dendromass were burned in domestic boiler with fuel container, which allows make mixtures of two different biofuels in various ratios. There were monitored thermal power, production of gaseous emissions, particulate matters production and flue gas temperature, which ensured optimal combustion process. Used boiler contained fuel container, so it was a continuous combustion of biofuel. Measurements showed that the use of mixtures of phytomass and dendromass is important mainly because the addition of dendromass can increase thermal power of boiler and reduce emissions production in comparison with separate phytomass combustion.
PL
Wykorzystanie źródeł energii odnawialnej stanowi wielki potencjał dla przemysłu i gospodarstw domowych - obecnie, a także w przyszłości. Biomasa odgrywa ważną rolę w redukcji konsumpcji kopalnych paliw. Jakkolwiek, biomasa dzieli się na biomasę roślinną (fitomasę), biomasę drzewną (dendromasę) oraz biomasę zwierzęcą (zoomasę), to daje nam możliwość wykorzystania zanieczyszczeń rolniczych – tj. fitomasy. Fitomasa jest w porównaniu do biomasy drzewnej bardziej dostępna ekonomicznie, ale właściwości spalania fitomasy są gorsze. W naszej pracy zdecydowaliśmy się użyć fitomasy i biomasy drzewnej w różnych stosunkach w celu uzyskania lepszego procesu spalania. Dla porównania była spalana biomasa drzewna bez dodatku fitomasy. Fitomasa z dendromasą była natomiast spalana w specjalnych domowych kotłach z zasobnikiem paliwa, który umożliwia zrobienie mieszaniny dwóch różnych biopaliw w różnych stosunkach. Monitorowano moc cieplną kotła, produkcję emisji gazów, produkcję pyłu zawieszonego i temperaturę spalin, które zapewniały optymalny proces spalania. Wykorzystywano kocioł, który zawierał zbiornik paliwa, więc było to ciągłe spalanie biopaliwa. Pomiary pokazały, że użycie mieszaniny fito-i dendromasy jest istotne, przede wszystkim dlatego, że dodatek biomasy drzewnej może zwiększyć moc cieplną kotła i zredukować produkcję emisje w porównaniu z oddzielnym spalaniem fitomasy.
The paper analyzes the influence of humidity of combusted wood biomass on the flue gas losses. A mathematical relation between flue gas losses of the boiler on wood biomass humidity is presented as well as temperature of flue gas emitted from the boiler into the atmosphere. The limits of model application for the humidity of wood biomass falls into the interval 10–60% whereas the range of temperatures of flue gases emitted from the boiler to the atmosphere is 120–200°C. The influence of the humidity of wood biomass has an adverse effect on increasing the extent of the boiler flue gas losses and thus inefficiency of the heat production. The increase of the wood biomass humidity from the value of 10% to 60% with the outlet temperature of flue gases from the boiler 120°C causes an increase in flue gas loss of the boiler from the value 8.37% to 12.43%, similarly the increase of flue gas loss by 200°C from 15.19% to 22.55%, or the increase of the flue gas loss by 7.36%.
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During operation of the OP-380 boiler under transient conditions, for example during start-up and shutdown of the power unit, on the circumference of horizontal pressure elements like a drum, inlet and outlet headers, considerable temperature differences are observed. The duration of each start-up and shutdown is relatively long because is limited by thermal stresses caused by temperature changes. The paper presents the method of the maximum stresses arising during operation in transient states determination, based on the measurement of temperature on the outer surface of the thick-walled pressured element. The presented measuring system, including the described method has been implemented in the OP-380 boiler at EDF Krakow. This system will act as a thermal constraints system, whose main task is to protect the equipment against exceeding the maximum allowable thermal stress. This method will also allow assessment of the viability of thick-walled components based on the values of the stresses that occur during long-term operation of the boiler.
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Municipal waste, including sewage sludge and biomass can be a source of energy used in professional energy generation and heating. The possibility of using waste in the form of municipal sewage sludge in heat installations in power industry as a composite of alternative fuels is limited to their type, homogeneity and fuel properties. The article presents the possibility of using waste - code 19 08 05 stabilized municipal sewage sludge as an admixture to hard coal and lignite as well as to biomass, that is straw and wood. Energy recovery generated from alternative fuel composites will be conducted in boilers. The properties of produced fuels and emissions of produced pollutants into the environment have been presented.
The paper presents a concept of producing energy on the basis of modern alternative fuels to be burnt in low- and medium-power stokerfired boilers. The thermal energy contained in water vapour and hot water will be utilized in producing, in combination, of electrical energy, and for heating of cubature objects. Modern alternative fuels in the form of briquettes and pellets will be produced from hard coals and municipal waste other than hazardous. There have been presented the properties of alternative fuels obtained, and the concept of their utilization in the process of energy production in cogeneration.
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Biogaz jest nośnikiem energii wytwarzanym z substancji organicznej (biomasy) w procesie fermentacji beztlenowej. Preferowana droga wykorzystania tego paliwa jest przede wszystkim produkcja energii elektrycznej, która w prosty sposób, z wysoką sprawnością może być zamieniana na dowolną postać energii. Biogaz wymaga zastosowania procesów oczyszczania z siloksanów i związków siarki. Istotnym etapem w oczyszczaniu biogazu jest właściwa detekcja zawartości siloksanów.
EN
Biogas is an energy carrier produced from organic matter (biomass) in the process of anaerobic digestion. The preferred way of using this fuel is primarily the production of electricity, which in a simple way can be converted to any form of energy. Biogas purification requires the use of processes of siloxanes and sulfur compounds. An important stage of the biogas treatment installation is appropriate detection of siloxane concentration.
The paper presents a thermomechanical computational solid mechanics analysis (CSM) of a pipe "double omega", used in the steam superheaters in circulating fluidized bed (CFB) boilers. The complex crosssection shape of the "double omega" tubes requires more precise analysis in order to prevent from failure as a result of the excessive temperature and thermal stresses. The results have been obtained using the finite volume method for transient state of superheater. The calculation was carried out for the section of pipe made of low-alloy steel.
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