Comparison of Catalysts in the Point of View of Pellet Stove Flue Gas Purification

Monolithic catalysts are used as a method for the flue gases purifying by oxidation of gas products from incomplete combustion. This study is focused on three different types of monolithic catalysts and quantification of their degree of influence on mass concentration of carbon monoxide (CO) and organic gaseous compounds (OGCs) in real small-scale wood pellet stove. Catalysts were placed right behind the stove at the flue gas outlet. The comparison consisted of quantification of their influence on the selected pollutants during the few-hours steady operation of the small-scale pellet stove. Reference values of the selected pollutants were defined during the combustion test without a catalyst installed. In this article, three catalysts based on different active compounds: WO3–V2O5, Pd and Pt were tested. The palladium-based catalyst has proven the best degree of conversion of CO (almost 78%). The platinum-based catalyst has proven the best degree of conversion of OGC (almost 64%). Due to a big degree of clogging by solid particles of all catalysts during the tests, it is impossible to operate the chosen stove with tested types of catalysts in normal operation at home conditions. Without any type of periodical cleaning (every few hours), there is a serious danger of leakage of the flue gas out of the stove. Further investigations should evaluate the degree of clogging in a long-term operation and should propose a method to avoid any danger of the flue gas leaking caused by the catalysts.This article was prepared within OP RDE, the project ‘Research on the identification of combustion of unsuitable fuels and systems of self-diagnostics of boilers combusting solid fuels for domestic heating’, identification code CZ.02.1.01/0.0/0.0/18_069/0010049, with the financial support from the European Regional Development Fund. This article was also prepared within the project SP2019/83 ‘Monitoring the operating parameters of a small combustion equipment and determining its effect on condensation of water in the flue gas’ and was elaborated in the framework of the grant program ‘Support for Science and Research in the Moravia-Silesia Region 2018’, (RRC/10/2018), financed from the budget of the Moravian-Silesian Region

Beech Leaves Briquettes’ and Standard Briquettes’ Combustion: Comparison of Flue Gas Composition

Biomass stoves are not only popular, widespread and important sources of heat but are also not negligible sources of pollutants. The present study had two objectives in this field of research. The first one was to determine the difference between standard wooden and beech leaves briquettes flue gas composition during similar, standard home combustion conditions. The second objective was to determine the possibility of decreasing the mass concentration of pollutants contained in the flue gas produced by standard and alternative fuel combustion, i.e. wooden briquettes and beech leaves briquettes, by an oxidation catalyst. Significantly higher mass concentration of nitrogen oxides (NOx), almost 2.5 times higher, in the flue gas was observed during the beech leaves combustion. Both fuels reached the edge of actual legislation limit (European Standard Commission regulation [EU] 2015/1185) in case of mass concentration of carbon monoxide (CO). This issue was solved by a palladium-based catalyst with average degree of conversion around 82%. The catalyst also influences flue gas composition from mass concentration of propane point of view with average degree of conversion around 15%. The mass fraction of sulphur, occurring in the beech leaves briquettes, did not cause any issue to the catalyst in terms of its degree of CO conversion. Due to the test results from the beech leaves briquettes, i.e. high mass fraction of ash and high mass concentration of NOx in the flue gas, it is appropriate to use this kind of fuel as secondary fuel during the co-combustion process.This work was supported by the Doctoral grant competition VŠB TU-Ostrava, reg. no. CZ.0 2.2.69/0.0./0.0/19_073/0016945 within the Operational Programme Research, Development and Education, under project DGS/TEAM/2020-035 "Determination of oxidation catalysts characteristics during the flue gas purification"

Enlargement of Measurement Range of ERC Drop Tube

Better understanding of combustion process in large scale pulverized coal boilers can help with increasing of coal combustion efficiency and decreasing of pollutant emissions, such as nitrogen oxides and arguable carbon dioxide. This improvement cannot be performed without testing in laboratory conditions. For this purpose, a new testing facility called the drop tube has been built in the Energy Research Center (ERC) of VSB-Technical University of Ostrava. This paper describes the methodology of pulverized coal thermo-kinetic properties determination with the use of the Drop Tube Test Facility and the first steps in improvement of this methodology. There is a new design of the sampling probe, an improved one, gas-tight double-wall design, implemented into the methodology lately. The intermediate space is vacuumed for the purpose of better isolating properties of the probe. Further, the probe is newly supplemented with a cryogenic control valve for smooth regulation of small flow rates of cooling media - liquid nitrogen. These innovations bring cooling media savings, especially thanks to increased efficiency of this media’s cooling potential. Furthermore, smoother regulation allows a sample cooling in an accurately defined point