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1

Prędkość zwęglania wybranych krajowych gatunków drewna

Sulik Paweł

Materiały Budowlane

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2022

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nr 9

99--102

PL

W artykule przedstawiono wyniki badań prędkości zwęglania dziewięciu występujących w Polsce gatunków drewna, obejmujących świerk, sosnę, brzozę, buk, jesion, topolę, dąb, klon i grochodrzew. Odniesiono się do zasobności polskich lasów, z uwzględnieniem podziału na poszczególne gatunki botaniczne, potwierdzając ich przydatność do zastosowania w budownictwie ze względu na prędkość zwęglania. Uwzględniając zasoby leśne Polski oraz zachowanie w trakcie pożaru, najlepiej rokuje wykorzystanie drewna sosny w konstrukcjach typu CLT, czyli z drewna jednego gatunku. W przypadku rozwiązań łączących różne gatunki w elementach CLT, warto rozważyć zastosowanie grochodrzewu lub dębu w warstwach zewnętrznych, ponieważ prędkość ich zwęglania jest najniższa z przebadanych.

EN

The paper presents the results of research on the charring rate of 9 types of wood found in Poland, including spruce, pine, birch, beech, ash, poplar, oak, maple and robinia. Reference was made to the abundance of Polish forests, taking into account the division into individual botanical species, confirming their suitability for use in construction due to the charring rate. Taking into account Poland's forest resources and behaviour during a fire, the best prognosis is the use of pine wood in single-species CLT-type constructions. In the case of solutions combining different species in CLT elements, it is worth considering the use of robinia or oak in the outer layers, the charring rates of which are the lowest among those tested in the work.

2

Wpływ gatunku drewna na charakterystykę wytrzymałościową belki drewnianej w sytuacji pożaru

Kmiecik Kamil

Materiały Budowlane

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2019

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nr 5

64--65

PL

W artykule przedstawiono symulacje numeryczne przepływu ciepła przez belki drewniane różnych klas, w warunkach pożaru standardowego ISO. Modele numeryczne wykonano w programie SAFIR. Następnie, na podstawie izotermy 300 określono przekroje belek zmieniające się podczas pożaru. Finalnie uzyskano wytężenie belek wykonanych z różnych gatunków drewna, w sytuacji pożaru.

EN

The article presents numerical simulations of heat flow through timber beams of different classes, in the conditions of standard ISO fire. Numerical models were made in the SAFIR program. Then, the beam cross-sections were determined on the basis of the 300 isotherm. Finally, effort of beams made of various types of wood were obtained in a fire situation.

3

Dissolution of carbon from coke and char in liquid Fe-C alloys

Xing X., Jahanshahi S., Yang J., Ostrovski O.

Archives of Materials Science and Engineering

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2018

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Vol. 92, nr 1

22--27

EN

Purpose: The aim of this paper was to study dissolution of carbon from carbonaceous materials of different origin with different morphology, microtexture and microstructure in the liquid Fe-C alloys. Design/methodology/approach: The dissolution of carbon from coke, char and glassy carbon in the molten Fe-C alloy (initial carbon concentration 2.46 wt.%) at 1350°C was measured and compared with that from graphite. The dissolution of carbon from demineralised coke and char in the Fe-C solution was also examined to study the effect of mineral matter on the carbon dissolution. Findings: The concentration of carbon in the Fe-C solution dissolved from graphite was higher than that from coke and char. Demineralisation of coke and char had a significant effect on the carbon dissolution. The concentration of carbon dissolved from demineralised coke and char in the Fe-C alloy approached the solubility of graphite in this alloy under the same conditions. Results obtained in this work confirmed that ash has a strong effect on the carbon dissolution. Research limitations/implications: Investigations in this paper were conducted at 1350°C. At higher temperatures; (1) the degree of coke and char graphitisation increases changing the microstructure of carbonaceous materials; (2) the ash can melt, and (3) some of the metal oxides in the ash can be reduced by carbon to the metal phase, thereby weakening the effect of ash on the carbon dissolution. Demineralisation of coke was incomplete; it reached 70-80% with some effect on the carbon dissolution. The effect of ash composition and further coke demineralisation on the carbon dissolution at higher temperature will be investigated in the future study. Originality/value: This study demonstrated that dissolution of carbon from coke and char was strongly affected by ash. Reactions of dissolution of carbon from coke and char in liquid Fe-C alloy reached a steady state within 1-2 hours. In this state, the coke/char - metal system was far from equilibrium. The “apparent” activity which can be assigned to carbon in the steady state is below one for graphite with significant implications for metallurgical processes.

4

Modeling on Char Combustion Characteristics in Fly-ash and Its Countermeasure Improved for Circulating Fluidized Bed Boilers

Fan B., Liu X., Qiao X., Jin Y.

Przegląd Elektrotechniczny

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2013

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R. 89, nr 3b

1--3

EN

A mathematical model of single char particle combustion in circulating fluidized bed (CFB) boiler is developed in this paper. Its numerical solution in operating conditions of CFB boiler verifies the nature of a phenomenon that the distribution of carbon content of char particles in fly-ash has a peak value versus their diameters. When the temperature of the fine char particle is close to the bed temperature, there also exists a peak value for its burn-out time. The fly-ash recirculation and the hot cyclone are presented to improve combustion of char particles.

PL

W artykule przedstawiono model matematyczny zapłonu zwęglonych cząstek (sadzy) w kotle z cyrkulacją warstwową fluidalną (ang. Circulating Fluidized Bed – CFB). Wyjaśniono w ten sposób charakterystykę rozkładu zawartego w cząstce węgla oraz wpływu temperatury cząstki na szybkość wypalania. Dla poprawy sprawności procesu, zaproponowano zastosowanie recyrkulacji lotnych popiołów oraz wiru gorącego powietrza.

5

Study of properties of expanded graphite - polymer porous composite by acoustic emission method

Berdowski J., Berdowska S., Aubry F.

Archives of Metallurgy and Materials

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2013

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Vol. 58, iss. 4

1331--1336

EN

The purpose of this paper was to investigate the physical and mechanical properties of compressed expanded graphite (CEG) and their porous derivatives after impregnation, polymerization; and carbonization by the use of acoustic emission method (AE). The mechanical and structural characteristics of compressed expanded graphite and their three groups of porous composites after each technological process are presented and discussed. The measurements of acoustic emission parameters in these materials were carried out at wide range of frequency of the waves (0.1÷2.5 MHz). The changes of two of parameters: - AE pulses counts rate and spectrum distribution of AE waves - are presented in this paper. The analysis of the respective parameters AE also gives possibility to determine the micro- and macro structural changes of materials at different levels of technological processes. Applications of these materials as catalysts with high specific surface make them very interesting subject of study. Also compressed expanded graphite composite membranes prepared from furfuryl alcohol polymers are promising for gas separation.

PL

Cel pracy stanowiło zbadanie przy użyciu metody emisji akustycznej (EA) fizycznych i mechanicznych właściwości sprasowanego grafitu ekspandowanego (SGE) i jego porowatych pochodnych kompozytowych, otrzymanych po procesach impregnacji, polimeryzacji i karbonizacji. Przedstawiono i przedyskutowano mechaniczne i strukturalne charakterystyki sprasowanego grafitu ekspandowanego i trzech porowatych kompozytów otrzymanych na jego bazie, po kolejnych procesach technologicznych. Pomiary parametrów zarejestrowanych sygnałów EA w tych materiałach wykonano w szerokim przedziale częstotliwości emitowanych w materiale fal (0,1-2,5 MHz). W pracy przedstawiono zmiany dwu z tych parametrów: szybkości zliczeń impulsów i rozkładu widmowego emitowanych fal. Analiza poszczególnych parametrów emisji akustycznej stwarza możliwości określenia mikro- i makrostrukturalnych zmian w materiałach, wytworzonych na różnych etapach procesu technologicznego. Przewidywane szerokie zastosowanie tych materiałów jako katalizatorów, posiadających bardzo duże powierzchnie właściwe, czyni je niezwykle interesującym przedmiotem badań. Również bardzo perspektywiczne jest wykorzystanie kompozytowych membran z matrycą ze sprasowanego grafitu ekspandowanego, wypełnionego polimerem alkoholu furfurylowego. do separacji gazów.

6

Pyrolysis products from biomass/synthetic polymer mixtures as potential energy source

Rutkowski P., Świetlik U., Beran E.

Polish Journal of Applied Chemistry

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2006

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Vol. 50, nr 1-2

29-39

EN

Bio-oils and chars obtained during pyrolysis carried out in a horizontal rotary oven at 500°C under argon flow and the heating rate of 20°C min"1 from pine wood sawdust, polystyrene and 9:1,3:1, 1:1 (w/w) wood/polystyrene mixtures were investigated in view of their application as fuels. The composition of the blend strongly influences the yield and basic properties of pyrolysis products. The higher proportion of polystyrene in the blend, the higher yield of bio-oil and the lower yield ofcharwas observed. The polystyrene addition to pine wood clearly reduces the amount of pyrolytic water in liquid products. All resulted chars are characterized with similar heating value higher than 31 MJ kg'1. Moreover, it was found that ultimate compositions of chars do not significantly depend on the polystyrene addition to biomass in starting blends. Although the visible increase of carbon content and the decrease of oxygen content is observed, the change is not distinct. On the contrary, the carbon and oxygen content as well as the physicochemical properties of oils are strongly influenced by the blend composition but do not change additively. The addition of polystyrene to pine wood sawdust clearly improves the fuel quality, i.e. pour point, viscosity, total acid number and high heating value. The influence of water removal from bio-oils on their physicochemical properties was also determined. Although it was found that water removal from bio-oil gives product with better properties, bio-oils need improvement of chemical structure to meet requirements for fuels.

7

Modification of the properties and carbonization behaviour of coal tar pitches on progressive air-blowing

Machnikowski J., Gerus-Piasecka J., Kubica K., Machnikowska H.

Polish Journal of Chemical Technology

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2001

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Vol. 3, nr 1

7-14

EN

Pitches with softening points of about 140°C, 175°C and 210°C were prepared by progressive air-blowing at 300°C of coal-tar pitches from different commercial coke-oven tars. The modification induced by the mild oxidation was monitored using solvent fractionation, elemental analysis and contact angle measurement. The kinetics and mechanism of mesophase formation on isothermal treatment at 450°C and the optical texture of resultant cokes were studied by polarized-light optical microscopy. The air-blowing increases gradually the coking yield and toluene insoluble content of pitch with very little changes in quinoline insoluble content and elemental composition. The modified pitches preserve characteristic structural features of parent materials. Air-blowing accelerates the formation of mesophase on carbonization and modifies to a different extent the mechanism of the transformation. QI particles tend to form large aggregates in the early stage of the transformation and mesophase growth occurs in the practically Ql-free pitch, leading to two-phase optical texture of resultant cokes.

8

Optimization of the carbonization and filtration processes in soda industry

Buczkowski R., Szymański T.

Polish Journal of Applied Chemistry

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1998

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Vol. 42, nr 1

57-69

EN

The mathematical description of the ammonia-water carbonation process solutions of sodium chloride with special regard to the influence of temperature-and-supersaturation parameters on the filtration properties of the reaction suspension has been presented in this work. On the base of experimental results and literature data the correlation between the granulometric composition of sodium bicarbonate cystals and the specific resistance and the humidity of filter cake has been determined. New solution concerning the technology and apparatus of the carbonation node and the filtration on the industrial scale has been presented.