Dagmar Juchelková

Conditions for energy generation as an alternative approach to compost utilization

Very strict limits constrain the current possibilities for compost utilization in agriculture and for land reclamation, thus creating a need for other compost utilization practices. A favourable alternative can be compost utilization as a renewable heat source – alternative fuel. The changes of the basic physical–chemical parameters during the composting process are evaluated. During the composting process, energy losses of 920 kJ/kg occur, caused by carbohydrate decomposition (loss of 12.64% TOC). The net calorific value for mature compost was 11.169 kJ/kg dry matter. The grain size of compost below 0.045 mm has the highest ash content. The energetic utilization of compost depended on moisture, which can be influenced by paper addition or by prolonging the time of maturation to six months.

Effect of unburned carbon content in fly ash on the retention of 12 elements out of coal-combustion flue gas

The aim of this study was to evaluate whether unburned carbon particles present in fly ash can help in the retention of S, Cl, Br, As, Se, Cu, Ni, Zn, Ga, Ge, Rb, and Pb out of flue gas during the coal combustion at fluidised-bed power station where the coal was combusted along with limestone. The competitive influence of 10%-25% CaO in fly ashes on the distribution of studied elements was studied as well to be clear which factor governs behaviour of studied elements. Except of S (with significant association with CaO) and Rb and Pb (with major affinity to Al2O3) the statistically significant and positive correlation coefficients were calculated for the relations between unburned carbon content and Br (0.959), Cl (0.957), Cu (0.916), Se (0.898), Ni (0.866), As (0.861), Zn (0.742), Ge (0.717), and Ga (0.588) content. The results suggest that the unburned carbon is promising material in terms of flue gas cleaning even if contained in highly calcareous fly ashes.

Syngas Production from Pyrolysis of Nine Composts Obtained from Nonhybrid and Hybrid Perennial Grasses

A pyrolysis of compost for the production of syngas with an explicit H2/CO = 2 or H2/CO = 3 was investigated in this study. The composts were obtained from nonhybrid (perennial) grasses (NHG) and hybrid (perennial) grasses (HG). Discrepancies in H2 evolution profiles were found between NHG and HG composts. In addition, positive correlations for NHG composts were obtained between (i) H2 yield and lignin content, (ii) H2 yield and potassium content, and (iii) CO yield and cellulose content. All composts resulted in H2/CO = 2 and five of the nine composts resulted in H2/CO = 3. Exceptionally large higher heating values (HHVs) of pyrolysis gas, very close to HHVs of feedstock, were obtained for composts made from mountain brome (MB, 16.23 MJ/kg), hybrid Becva (FB, 16.45 MJ/kg), and tall fescue (TF, 17.43 MJ/kg). The MB and FB composts resulted in the highest syngas formation with H2/CO = 2, whereas TF compost resulted in the highest syngas formation with H2/CO = 3.

Temporal and seasonal variations of black carbon in a highly polluted European city: Apportionment of potential sources and the effect of meteorological conditions

Black carbon - a primary component of particulate matter emitted from an incomplete combustion of fossil fuels, biomass, and biofuels - has been found to have a detrimental effect on human health and the environment. Since black carbon emissions data are not readily available, no measures are implemented to reduce black carbon emissions. The temporal and seasonal variations of black carbon concentrations were evaluated during 2012-2014. The data were collected in the highly polluted European city - Ostrava, Czech Republic, surrounded by major highways and large industries. Significantly higher black carbon concentrations were obtained in Ostrava, relative to other European cities and the magnitude was equivalent to the magnitude of black carbon concentrations measured in Poland and China. The data were categorized to heating and non-heating seasons based on the periodic pattern of daily and monthly average concentrations of black carbon. A higher black carbon concentration was obtained during heating season than non-heating season and was primarily associated with an increase in residential coal burning and meteorological parameters. The concentration of black carbon was found to be negatively correlated with temperature and wind speed, and positively correlated with the relative humidity. Other black carbon sources potentially included emissions from vehicle exhaust and the local steel-producing industry.

The effect of moisture on the release and enrichment of heavy metals during pyrolysis of municipal solid waste

The investigation of the effect of moisture on the release and enrichment of heavy metals during pyrolysis of municipal solid waste is essential. This is important owing to: (i) the increasing amount of metals in the solid product of pyrolysis beyond the normalised level; (ii) the effect of moisture on the overall cost of pyrolysis process; and (iii) the utilisation of pyrolysis products. Seven metals were selected for evaluation: arsenic, cadmium, chromium, mercury, nickel, lead, and vanadium. Pyrolysis experiments were conducted in a steel retort at 650 °C. The municipal solid waste samples with moisture contents of 0, 30, and 65 wt% were investigated. The relative enrichment index and release of heavy metals were evaluated individually for liquid and solid fractions. A consistent trend was observed for the majority of metals investigated. Reductions of relative enrichment index and release, i.e. an increase of volatility, were observed for arsenic, chromium, cadmium, nickel, and vanadium, with an increase of municipal solid waste moisture. Whereas divergent results were obtained for lead and mercury. The effect of moisture on the relative enrichment index and release was greater at 65 wt% moisture than at 30 wt% for lead, and more remarkable at 30 wt% than at 65 wt% for mercury.

Experimental Determination of Energy Demand and Spatio-Temporal Course of Pyrolysis for Various Materials

The article presents a detailed analysis of brown coal, rubber and polyethylene pyrolysis in a horizontal reactor of a thermic facility. It is a facility continuously processing entry materials flowing in the amount of up to 150 Kg.h -1 and with the total maximum heaters’ output of 200 kW. The attention has been paid to the thermal input of the pyrolysis process and to the description of physical-chemical processes in time and the reactor space. The objective has been to find out the best combination of entry material and process conditions from the point of view of pyrolysis energy intensity. The article specifics are based on the fact that the mentioned processes have been analysed in a large facility having the semi-production characteristics, not within a laboratory system used usually in this kind of research (DSC).

Conversion of Syngas to LPG and Aromatics Over Commercial Fischer-Tropsch Catalyst and HZSM-5 in a Dual Bed Reactor

The commercial Co-based Fischer-Tropsch catalyst and HZSM-5 were tested in a single reactor process. FT catalyst was evaluated at 463 K, whereas HZSM-5 was evaluated at various temperatures (523, 573, and 623 K). The effect of syngas flow rate, HZSM-5 temperature and loading on liquefied petroleum gas (LPG) and aromatics selectivities were investigated. HZSM-5 addition suppressed the formation of CO2 and CH4, and remarkably enhanced the simultaneous formation of LPG and aromatics. The optimal operating conditions were identified as: THZM-5 = 623 K, HZSM-5 loading = 2.5 g, and GHSV = 4.8 Lsyngas/(gcat h).

Possibilities thermal utilization of solid char from pyrolysis of municipal solid waste

Requirements for quality of solid char from pyrolysis of municipal solid waste were studied from the point of view of possible utilization for combustion. Laboratory tests of pyrolysis were carried out with samples of municipal solid waste with various moisture. Mineral phases in solid char were determined by X-ray diffraction. Behavior of hazardous elements during pyrolysis was studied and possibility to control selected risk elements by technical means was proposed.

Perennial grasses as prospective energy sources

ABSTRACT Properties of nine composts obtained from perennial grasses for their potential use as an energy source were assessed in this study. The majority of grasses displayed high-moisture, hemicellulose, Na, K, Cl, and N contents, but low lignin content. The effect of composting was pronounced in (i) enhancement of lignin to 461.29%, fixed carbon to 49.46%, and cellulose to 35.05%; and (ii) reduction of Na to 98.77%, moisture to 93.49%, hemicellulose to 89.15%, K to 88.21%, N to 84.43%, Cl to 23.15%, and volatile matter to 12.57%. Subsequently, an increase in higher heating value to 13.90% was observed.

Properties of Process Gas Combustion Products

The study deals with the issue of combustion of process gas that resulted from the pyrolyticly processed varied organic materials. The study describes combustion properties of the gas and the properties of the combustion product considering kinds of the entry materials. The selected materials (coal, rubber, or biomass) were pyrolysed at the temperature of 650°C in the experimental system having the maximal heat output of 200 kW. It was the system with the continual intake of entry materials the flow of which could reach the maximum of about 150 kg.h-1.