scholarly journals Dependence of the boiler flue gas losses on humidity of wood biomass

2015 ◽  
Vol 36 (4) ◽  
pp. 77-86 ◽  
Author(s):  
Ladislav Dzurenda ◽  
Adrián Banski

Abstract 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%.

2017 ◽  
Vol 38 (1) ◽  
pp. 63-74 ◽  
Author(s):  
Ladislav Dzurenda ◽  
Adrián Banski

Abstract 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%.


1991 ◽  
Vol 56 (4) ◽  
pp. 831-846 ◽  
Author(s):  
Petr Stehlík

By means of a mathematical model simulating thermal chemical processes taking place in primary reformer radiation chamber, the influence of selected parameters on main characteristic quantities in steam reforming process was investigated. The parameters were divided into inlet parameters on flue gas side, inlet parameters on reaction mixture side and those of radiation chamber geometry. As main characteristic quantities outlet temperature of reaction mixture, maximum temperature of reaction tubes outer surface, outlet temperature of flue gases, absorbed heat, methane conversion into carbon dioxide and carbon monoxide as well as temperature distance from equilibrium were chosen.


1991 ◽  
Vol 24 (7) ◽  
pp. 277-284 ◽  
Author(s):  
E. Gomólka ◽  
B. Gomólka

Whenever possible, neutralization of alkaline wastewater should involve low-cost acid. It is conventional to make use of carbonic acid produced via the reaction of carbon dioxide (contained in flue gases) with water according to the following equation: Carbon dioxide content in the flue gas stream varies from 10% to 15%. The flue gas stream may either be passed to the wastewater contained in the recarbonizers, or. enter the scrubbers (which are continually sprayed with wastewater) from the bottom in oountercurrent. The reactors, in which recarbonation occurs, have the ability to expand the contact surface between gaseous and liquid phase. This can be achieved by gas phase dispersion in the liquid phase (bubbling), by liquid phase dispersion in the gas phase (spraying), or by bubbling and spraying, and mixing. These concurrent operations are carried out during motion of the disk aerator (which is a patent claim). The authors describe the functioning of the disk aerator, the composition of the wastewater produced during wet gasification of carbide, the chemistry of recarbonation and decarbonation, and the concept of applying the disk aerator so as to make the wastewater fit for reuse (after suitable neutralization) as feeding water in acetylene generators.


1992 ◽  
Vol 25 (4-5) ◽  
pp. 307-314 ◽  
Author(s):  
A. W. van der Vlies ◽  
J. H. B. te Marvelde

Recycling of sewage sludge will soon no longer be possible in The Netherlands, or will be possible only to a very limited degree. For that reason, part of the sewage sludge will have to be incinerated. This will happen particularly in those areas where tipping space is very limited. A sludge incineration plant is planned to be built in the town of Dordrecht, with a capacity of 45,000 tonnes dry solids per year. The plant will be subject to the very strict flue gas emission requirements of the Dutch Guideline on Incineration. The Guideline demands a sophisticated flue gas purification procedure.


Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2174
Author(s):  
Marta Marczak-Grzesik ◽  
Stanisław Budzyń ◽  
Barbara Tora ◽  
Szymon Szufa ◽  
Krzysztof Kogut ◽  
...  

The research presented by the authors in this paper focused on understanding the behavior of mercury during coal combustion and flue gas purification operations. The goal was to determine the flue gas temperature on the mercury emissions limits for the combustion of lignites in the energy sector. The authors examined the process of sorption of mercury from flue gases using fine-grained organic materials. The main objectives of this study were to recommend a low-cost organic adsorbent such as coke dust (CD), corn straw char (CS-400), brominated corn straw char (CS-400-Br), rubber char (RC-600) or granulated rubber char (GRC-600) to efficiently substitute expensive dust-sized activated carbon. The study covered combustion of lignite from a Polish field. The experiment was conducted at temperatures reflecting conditions inside a flue gas purification installation. One of the tested sorbents—tire-derived rubber char that was obtained by pyrolysis—exhibited good potential for Hg0 into Hg2+ oxidation, resulting in enhanced mercury removal from the flue. The char characterization increased elevated bromine content (mercury oxidizing agent) in comparison to the other selected adsorbents. This paper presents the results of laboratory tests of mercury sorption from the flue gases at temperatures of 95, 125, 155 and 185 °C. The average mercury content in Polish lignite was 465 μg·kg−1. The concentration of mercury in flue gases emitted into the atmosphere was 17.8 µg·m−3. The study analyzed five low-cost sorbents with the average achieved efficiency of mercury removal from 18.3% to 96.1% for lignite combustion depending on the flue gas temperature.


Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3860
Author(s):  
Mária Hagarová ◽  
Milan Vaško ◽  
Miroslav Pástor ◽  
Gabriela Baranová ◽  
Miloš Matvija

Corrosion of boiler tubes remains an operational and economic limitation in municipal waste power plants. The understanding of the nature, mechanism, and related factors can help reduce the degradation process caused by corrosion. The chlorine content in the fuel has a significant effect on the production of gaseous components (e.g., HCl) and condensed phases on the chloride base. This study aimed to analyze the effects of flue gases on the outer surface and saturated steam on the inner surface of the evaporator tube. The influence of gaseous chlorides and sulfates or their deposits on the course and intensity of corrosion was observed. The salt melts reacted with the steel surface facing the flue gas flow and increased the thickness of the oxide layer up to a maximum of 30 mm. On the surface not facing the flue gas flow, they disrupted the corrosive layer, reduced its adhesion, and exposed the metal surface. Beneath the massive deposits, a local overheating of the inner surface of the evaporator tubes occurred, which resulted in the release of the protective magnetite layer from the surface. Ash deposits reduce the boiler’s thermal efficiency because they act as a thermal resistor for heat transfer between the flue gases and the working medium in the pipes. The effect of insufficient feedwater treatment was evinced in the presence of mineral salts in the corrosion layer on the inner surface of the tube.


2004 ◽  
Vol 126 (2) ◽  
pp. 119-124 ◽  
Author(s):  
O. S. Shokoya ◽  
S. A. (Raj) Mehta ◽  
R. G. Moore ◽  
B. B. Maini ◽  
M. Pooladi-Darvish ◽  
...  

Flue gas injection into light oil reservoirs could be a cost-effective gas displacement method for enhanced oil recovery, especially in low porosity and low permeability reservoirs. The flue gas could be generated in situ as obtained from the spontaneous ignition of oil when air is injected into a high temperature reservoir, or injected directly into the reservoir from some surface source. When operating at high pressures commonly found in deep light oil reservoirs, the flue gas may become miscible or near–miscible with the reservoir oil, thereby displacing it more efficiently than an immiscible gas flood. Some successful high pressure air injection (HPAI) projects have been reported in low permeability and low porosity light oil reservoirs. Spontaneous oil ignition was reported in some of these projects, at least from laboratory experiments; however, the mechanism by which the generated flue gas displaces the oil has not been discussed in clear terms in the literature. An experimental investigation was carried out to study the mechanism by which flue gases displace light oil at a reservoir temperature of 116°C and typical reservoir pressures ranging from 27.63 MPa to 46.06 MPa. The results showed that the flue gases displaced the oil in a forward contacting process resembling a combined vaporizing and condensing multi-contact gas drive mechanism. The flue gases also became near-miscible with the oil at elevated pressures, an indication that high pressure flue gas (or air) injection is a cost-effective process for enhanced recovery of light oils, compared to rich gas or water injection, with the potential of sequestering carbon dioxide, a greenhouse gas.


2019 ◽  
Vol 9 (4) ◽  
pp. 27-32
Author(s):  
Olga A. BALANDINA ◽  
Svetlana M. PURING

The analysis of the values of the concentrations of the formed nitrogen oxides and the temperatures of the jet plume under various conditions of mixture formation is carried out. The plots of the distribution of torch temperatures and concentrations of nitric oxide in the calculated area for oxidizer temperatures of 20, 60, 100, 150, and 200 ° C were obtained and analyzed. Mathematical modeling of the gaseous fuel combustion process was carried out using the FlowVision software package. An analysis of the results showed that a decrease in the temperature of the air supplied as an oxidizing agent leads to a significant decrease in the concentration of nitrogen oxides in flue gases, while not significantly affecting the change in the flame temperature. The research results can be used to solve the problems of optimizing boiler plants, in order to reduce harmful flue gas emissions. Further modeling is planned to determine the dependence of the influence of various factors on the degree of formation of nitrogen oxides in the flue gases of boiler plants.


2019 ◽  
Vol 137 ◽  
pp. 01021
Author(s):  
Maciej Żyrkowski ◽  
Monika Motak

Coal fired power plant are still responsible for vast amount of electricity and heat production in Poland in 2019. Increasing number of units is equipped with SCR reactors in order to mitigate NOx emission. Older units have been designed to work in a base load operation· however increasing number of intermittent energy sources on the market· forces power plant owners to operate such units in reduced load for significant number of hours in a year. Most of parameters in coal-fired boiler would change in reduced load operation· particularly flue gas parameters. That would affect the formation of ammonia bisulfate (NH4HSO4) as well as operation of SCR reactors in the boiler. The NH4HSO4 formation is highly undesired as it can plug the catalyst or heating surfaces in the boiler. To investigate this phenomenon· the NH4HSO4 formation was comprehensively studied. Moreover· reduced load operation of boiler in a medium size CHP plant was simulated· using computer modelling tools. Obtained parameters were used to analyse· how different flue gas parameters affect NH4HSO4 formation and what consequences does it have for boiler operation. In particular, effect related with operation of SCR reactors equipped with V2O5-WO3/TiO2 catalyst was deeply studied.


2019 ◽  
Vol 201 ◽  
pp. 06001
Author(s):  
Maciej Cholewiński ◽  
Wiesław Rybak

In this work a new lab-scale method dedicated to the evaluation of both concentration and oxidation level of mercury in flue gases from pulverised fuel fired boiler was proposed. To detect the abovementioned parameters, 2 main steps need to be evaluated. Firstly, a calorimeter bomb is utilised - by a proper implementation of mass balance of mercury within substrates and products, the quantity of oxidised mercury in gaseous products can be evaluated. Then, to simulate solid fuel fired power unit and to calculate mercury concentrations in flue gases, one of the stoichiometric mathematical models of combustion process must be applied. Early validation of the method showed considerable differences between solid fuels in mercury oxidation efficiencies and concentrations in flue gasses. Four examined fuels (lignite, hard coal and 2 types of solid biomass) was investigated. Calculated mercury concentrations in raw flue gas (>700°C) varied between 4 and 75 µg/m3ref. The lowest quantity of oxidised forms ofHg in flue gases were identified in the case of investigated lignite (27% of total Hg), while significantly higher – for selected hard coal (72%) and one type of biomass (with high chlorine concentration; up to 98%).


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