Wyniki wyszukiwania - Biblioteka Nauki

1

Innovative method of biomass combustion in the binary fluidised bed

100%

Leski K. , Berkowicz-Płatek G. , Żukowski W. , Szyman J.

Ecological Chemistry and Engineering. S

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2024

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tom Vol. 31, nr 3

353--363

EN

In this study, a binary fluidised bed made out of quartz sand and cenospheres for the biomass combustion process was created. Materials were fluidised with air to achieve a vertical density profile (from 0.5 g/cm³ to 1.1 g/cm³) resulting from grains segregation. The density profile was selected to ensure optimal control over the location of the combusted fuel particle. This involved positioning the process as close to the bottom sieve as possible. Fluidised bed combustion was carried out at temperatures of 600 °C, 700 °C, 820 °C and 870 °C using straw, willow and sawmill pellets as fuels. Qualitative and quantitative analysis of flue gases was performed using an FTIR spectrometer. Over 90 % carbon conversion from the biomass to carbon dioxide was achieved at 700 °C. At 820 °C and 870 °C, 100 % of biomass carbon left the reactor as CO2. The composition of organic compounds in the process products remained low, reaching a maximum of 3.0 % wt. at 600 °C. To gain further insights into the processes occurring in the immediate vicinity of biomass samples, a complementary TGA/FTIR analysis was conducted. This aimed to clarify the impact of the biomass particle decomposition stage in the fluidised bed combustion process. The proposed mechanism for biomass combustion in the binary fluidised bed contains the particle decomposition stage and the subsequent stage resulting from the coalescence of bubbles containing flammable components and bubbles containing oxidiser.

2

Sorption of hydrogen chloride in the fluidized bed reactor

100%

Olek M. , Żukowski W. , Baron J.

Ecological Chemistry and Engineering. S

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2019

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tom Vol. 26, nr 1

69--80

EN

Combustion of fuels, including renewable fuels and thermal treatment of waste (CFCs, pesticides), is associated with emissions of pollutants including halogens. The reversible process of sorption/desorption of HCl, in a fluidized (bubbling) bed reactor (BFB), during co-combustion of Cl-materials, was carried out. The thermal decomposition of methylene chloride (DCM, CH2Cl2) in an inert sand bed with the addition of the hydroxyapatite sorbent (HAp, Ca5(PO4)3(OH)) was investigated. The process parameters were as follows: temperature - 930 °C, the air excess - 1.3, stream rate of CH2Cl2 - 50 cm3/h. The concentration of HCl, CCl4, CHCl3, CH2Cl2, CH3Cl, COCl2 in the exhaust gases were monitored online with FTIR spectroscopy. The main chlorine product was hydrogen chloride. Samples of unprocessed HAp, taken from the bed during the process, and solid apatite residues were analyzed by X-ray diffraction (XRD). The content of chlorapatite (Ca5(PO4)3Cl) in the analyzed samples was respectively 11, 53 and 19 %. X-ray fluorescence (XRF) analysis showed the molar ratio of Ca:P:Cl was: 1.00:0.36:0.01, 1.00:0.36:0.09, 1.00:0.37:0.04 respectively. The HAp could be used as an sorbent of the HCl(g) during combustion of materials containing chlorine.

3

Effect of titanium source and sol-gel TiO2 thin film formation parameters on its morphology and photocatalytic activity

100%

Dulian P. , Zajic J. , Żukowski W.

Materials Science Poland

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2020

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tom Vol. 38, No. 3

424--433

EN

TiO2 thin films with different surface structure have been prepared from alkoxide solutions by the sol-gel method using different cationic precursors and heat treatment techniques. The effect of using titanium isopropoxide as well as titanium butoxide as a titanium source on the surface structure and photocatalytic activity of the resultant thin films was studied. Significant differences in the rate of hydrolysis and condensation reactions during the sol-gel synthesis were observed for these titanium precursors. This had a direct influence on the morphology of the as-prepared TiO2 films. Higher quality oxide coatings were obtained from titanium isopropoxide. They were characterized by a smaller grain size, improved surface roughness and uniform coverage of the glass substrate. A beneficial effect of calcination process after each sol application cycle in contrast to single step calcination after all dip-coating cycles was observed. Photocatalytic degradation tests showed that methyl orange was decolorized in the presence of all prepared TiO2 films by exposing their aqueous solutions to UV light (λ = 254 nm). The highest photocatalytic activity had the TiO2 layer produced using titanium isopropoxide.

4

Zastosowanie technologii spalania fluidalnego dla energetycznego wykorzystaniapaliw niskogatunkowych i odpadów

88%

Olek M. , Kandefer S. , Kaniowski W. , Baron J. , Żukowski W.

Przegląd Naukowo-Metodyczny „Edukacja dla Bezpieczeństwa”

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2014

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tom 7

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nr 3(24)

826-839

XX

W pracy przedstawiono zalety i ograniczenia technologii spalania w palenisku fluidalnym. Na przykładzie odpadów, uzyskanych po procesie wzbogacania węgla kamiennego (łupków węglowych), wskazano możliwość spalania substancji o niskiej kaloryczności (5,8-6,8 MJ/kg) i wysokim udziale części niepalnych (64-72%) w pęcherzowym palenisku fluidalnym. Łupki węglowe spalały się autotermicznie. Średnie stężenia SO2 i NOx, dla temperatury złoża 875ºC i współczynnika nadmiaru powietrza 1,6 były nie wyższe niż 2529 mg/Nm3 i 1560 mg/Nm3. W zaproponowanej technologii będzie konieczna redukcja emisji tych związków poprzez dodatek sorbentu wapiennego do złoża i związków amonowych do strefy nad złożem. Zaproponowane rozwiązanie konstrukcyjne paleniska może znaleźć zastosowanie dla jednostek o mocy do 5MW.

5

Struktura zanieczyszczeń pyłowych w Polsce na podstawie zautomatyzowanych pomiarów krótkoterminowych

75%

Szwed M. , Kozłowski R. , Żukowski W. , Mbengue S. , Suchánková L. , Prokeš R.

Przemysł Chemiczny

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2022

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tom T. 101, nr 6

393--397

PL

Przedstawiono wyniki analiz jakości powietrza opartych na automatycznych, krótkookresowych pomiarach pyłu w trzech punktach pomiarowych na terenie południowej Polski. Dokonano również analizy materiałów węglowych oraz składu chemicznego zdeponowanych na powierzchni filtrów cząstek stałych. Wykazano zróżnicowaną zawartość pyłu PM2.5, PM10 oraz różne postacie węgla w zależności od lokalizacji poboru próbek.

EN

Particulate matter concns. were measured in the atm. air by an optical aerosol spectrometer in the first quarter of 2022. Three locations in southern Poland with different land use characteristics, population d. and sources of pollution were selected for the study. The highest daily values of PM2.5 and PM10 were 29.6 and 31.0 μg/m3, resp., in the industrialized region, and the lowest 10.4 and 11.8 μg/m3, resp., in the agricultural region. The chem. compn. of the particles deposited on the quartz filter of the dust meter was detd. by SEM/EDS method.