PV Waste Thermal Treatment According to the Circular Economy Concept

Photovoltaic panels (PV) are one of the most popular technological solutions used to produce green renewable energy. They are known as green technology, but by analyzing a life cycle of a common panel, we can find out that production of these panels is strictly associated with generation of a large waste stream. PV modules are constantly modified and, therefore, it is required to consider the impact of the applied materials on the environment during the whole lifecycle of the product. The most important aspect of the assessment of a life cycle of a photovoltaic module in the phase of decommissioning is material recycling. The process of material recycling is very difficult, due to the lamination used in the currently exploited technology. This paper presents the results of pyrolysis for a sample of a silicon module. The results of the presented research show a weight loss of 48.16 in case of the tested samples. This paper presents the outcome of a quantitative analysis of the content of polycyclic aromatic for liquid and concentrations of Br, Cl and F for a gaseous fraction of pyrolysis products. The goal of the research presented in the paper was to find the optimal parameters for thermal separation, as well as the influence of the energy consumption and materials separation efficiency on the final thermal efficiency of the process.

Evaluation of Hydrogen Yield Evolution in Gaseous Fraction and Biochar Structure Resulting from Walnut Shells Pyrolysis

Conversion experiments of wet and dry walnut shells were performed, the influence of moisture content on the hydrogen yield in the gas fraction was estimated and the resulted biochar structure was presented. Measurements of the biochar structures were performed using X-ray diffraction and scanning electron microscopy methods. The results demonstrate that heating rate played a key role in the pyrolysis process and influenced the biochar structure. Under fast heating rate, the interactions between the water vapors released and other intermediate products, such as biochar was enhanced and consequently more hydrogen was generated. It could also be observed that both biochar samples, obtained from wet and dry walnut shells, had an approximately smooth surface and are different from the rough surface of the raw walnut shell, but there are not obvious differences in shape and pores structure between the two biochar samples. The increasing of the biochar surface area versus pyrolysis temperature is due tothe formation of micropores in structure. The biochar shows a surface morphology in the form of particles with rough, compact and porous structure. In addition the biochar structure confirmed that directly pyrolysis of wet walnut shells without predried treatment has enhanced the hydrogen content in the gas fraction.

Performance of Different Catalysts for the In Situ Cracking of the Oil-Waxes Obtained by the Pyrolysis of Polyethylene Film Waste

Currently, society is facing a great environmental problem, due to the large amount of plastic waste generated, most of which is not subjected to any type of treatment. In this work, polyethylene film waste from the non-selectively collected fraction was catalytically pyrolyzed at 500 °C, 20 °C/min for 2 h, in a discontinuous reactor using nitrogen as an inert gas stream. The main objective of this paper is to find catalysts that decrease the viscosity of the liquid fraction, since this property is quite meaningful in thermal pyrolysis. For this purpose, the three products of catalytic pyrolysis, the gaseous fraction, the solid fraction and the liquid fraction, were separated, obtaining the yield values. After that, the aspect of the liquid fraction was studied, differentiating which catalysts produced a larger quantity of waxy fraction and which ones did not. The viscosity of these samples was measured in order to confirm the catalysts that helped to obtain a less waxy fraction. The results showed that the zeolites Y and the zeolites β used in this study favor the obtaining of a compound with a smaller amount of waxes than for example catalysts such as FCC, ZSM-5 or SnCl2.

Pyrolysis of polystyrene waste for recovery of combustible hydrocarbons using copper oxide as catalyst

The present work is focused on pyrolysis of polystyrene waste for production of combustible hydrocarbons. The experiments were performed in an indigenously made furnace in the presence of a laboratory synthesised copper oxide. The pyrolysis products were collected and characterised. The Fourier transform infrared spectra showed that the liquid fraction contains C–H, C–O, C–C, C=C and O–H bonds, which correspond to various aliphatic and aromatic compounds. Gas chromatography–mass spectrometry traced compounds ranging from C1 to C4 in the gaseous fraction, whereas in the liquid fraction 15 components ranging from C3 to C24 were detected. From the results it has been concluded that CuO as a catalyst not only increased the liquid yield but also reduced the degradation temperature to great extent. Fuel properties of the pyrolysis oil were determined and compared with standard values of commercial fuel oil. The comparison suggested potential application of pyrolysis oil for domestic and commercial use.

Mass Balance of Plastic Waste Conversion to Fuel Oil- A case in Uganda

The current rate of plastic usage and the manner in which they are being disposed of is unsustainable. This is because more resources such as crude oil are utilized for their production and on the other hand, more waste plastics are generated. Since these waste plastics are made from crude oil, there is a high chance that they can be turned back into diesel that can be used to power irrigation pumps, drive engines for transport and industrial purposes among other potential uses. This paper sought to evaluate the pyrolysis of waste plastics to fuel oil potential of Uganda. The estimated waste plastics generated in Uganda was quantified as 545 851 kg/day. In this study, mass balance estimation indicated that the initial feed of 545 851 kg of waste plastics yields 451 419 kg liquid fuel using an appropriate technology for pyrolysis. The production potential of the gaseous and char fractions was calculated to be 50 764 and 43 668 kg in a day, respectively. This estimated amount has the potential to power approximately 234 small portable threshers of 5-7 horsepower. A total of 365 000 tonnes of fresh paddy can be threshed using these threshers. The gaseous fraction also has the potential to be used as a source of fuel for cooking. This is particularly important for postharvest handling and food security in Uganda as well as development of waste to energy technologies such as pyrolysis.

Ocean–atmosphere exchange of organic carbon and CO₂ surrounding the Antarctic Peninsula

Exchangeable organic carbon (OC) dynamics and CO2 fluxes in the Antarctic Peninsula during austral summer were highly variable, but the region appeared to be a net sink for OC and nearly in balance for CO2. Surface exchangeable dissolved organic carbon (EDOC) measurements had a 43 ± 3 (standard error, hereafter SE) μmol C L−1 overall mean and represented around 66% of surface non-purgeable dissolved organic carbon (DOC) in Antarctic waters, while the mean concentration of the gaseous fraction of organic carbon (GOC H–1) was 46 ± 3 SE μmol C L−1. There was a tendency towards low fugacity of dissolved CO2 (fCO2-w) in waters with high chlorophyll a (Chl a) content and high fCO2-w in areas with high krill densities. However, such relationships were not found for EDOC. The depth profiles of EDOC were also quite variable and occasionally followed Chl a profiles. The diel cycles of EDOC showed two distinct peaks, in the middle of the day and the middle of the short austral dark period, concurrent with solar radiation maxima and krill night migration patterns. However, no evident diel pattern for GOC H–1 or CO2 was observed. The pool of exchangeable OC is an important and active compartment of the carbon budget surrounding the Antarctic Peninsula and adds to previous studies highlighting its importance in the redistribution of carbon in marine environments.

Catalytic Effects at Pyrolysis of Wheat Grains Impregnated with Nickel Salts

Pyrolysis was performed on wheat grains untreated or impregnated with nickel nitrate solutions, into a fixed bed column, in the presence of a carbon dioxide stream. This produced a char with or without nickel, pyrolytic oil and a gaseous fraction. The distribution of these fractions was dependent on variations in heat flux, carbon dioxide superficial velocity and nickel nitrate solution concentration. The paper focused on establishing the qualitative and quantitative influence of these experimental variables on pyrolysis dynamics. In order to obtain a process characterization, a factorial experiment was used, wherein the pyrolysed material mass, collected oil mass, operating time, material bed temperature, volatiles temperature and column wall temperature were the evaluated process responses. A model reproducing pyrolysis curves was proposed considering the process dynamics as a result of competition between the appearance and extension of local pyrolysis points.

Reduction of Gaseous Boron Compounds in the Waste Gas of Glass Melting Furnaces

For boron containing glasses, you have to consider a gaseous fraction in the exhaust gas besides the particulate boron compounds. Within the framework of a research project finished in the year 2005 investigations into the emission of particulate and gaseous boron compounds were carried out on 18 glass melting furnaces with boron containing batch. The plants are different with regard to the molten glasses, furnace type, type of firing as well as downstream emission control technologies. The precipitation of particulate boron compounds is unproblematic. The precipitation of gaseous boron compounds is clearly more difficult and further measures have to be taken in respect of the effective precipitation. In a current follow up project, especially the reduction potential of gaseous boron compounds is investigated through the installation of a high temperature sorption stage (injection of fine-ground glass raw materials into the exhaust gas flow behind the superstructure at exhaust gas temperatures of 1400 °C) and/or the injection of alkaline solutions into the waste gas at lower temperatures. Investigations in the exhaust gas of E-glass melters were carried out successfully. Reduction rates of more than 95 % could be proved for gaseous boron compounds. The activities are supported by thermo-chemical calculations in the run up and during the measurements.