International Conference INTELLIGENT VALORISATION OF AGRO-INDUSTRIAL WASTES7-8 October 2021http://repository.utm.md/handle/5014/176922024-03-29T09:18:07Z2024-03-29T09:18:07ZBiogas – a sustainable energy solution from agro-industrial wastesVLADEI, NataliaCOVACI, Ecaterinahttp://repository.utm.md/handle/5014/177692021-10-18T12:14:03Z2021-01-01T00:00:00ZBiogas – a sustainable energy solution from agro-industrial wastes
VLADEI, Natalia; COVACI, Ecaterina
In the current global circumstances, a sustainable approach needs to be adopted to ensure successful food production and supply chain. The majority of agro waste are untreated and are disposed-off by burning. Consequently, as part of the global responsibility of safeguarding the earth and in consistence with the Kyoto protocol agreed by the United Nations, governments around the world have developed bio-based energy policies.
Nowadays, due to the increase in population, it is necessary to find a sustainable solution for the enhanced demand of energy in the world. The fossil fuels are limited and nonrenewable resources; the use of biomass for energy production seems to be a solution to provide energy and reduce the dioxide carbon emissions. The food-processing industry generates large quantities of residues, which may represent sustainable and rich sources of bioactive compounds. Agro- industrial residues provide an enormous potential to generate sustainable products and bioenergy.
This paper investigates the topic of finding a solution to protect and remedy the ecological problems caused by the food industry, namely the potential of biogas.
Biogas originates from bacteria in the process of bio-degradation of organic material under anaerobic conditions. The natural generation of biogas is an important part of the biogeochemical carbon cycle. Methanogens are the last link in a chain of micro-organisms which degrade organic material and return the decomposition products to the environment. In this process biogas is generated, a source of renewable energy.
The composition of biogas varies depending upon the origin of the anaerobic digestion process. Landfill gas typically has methane concentrations around 50%. Advanced waste treatment technologies can produce biogas with 55-75% CH4. Like those of any pure gas, the characteristic properties of biogas are pressure and temperature-dependent.
The calorific value of biogas is about 6 kWh/m3 - this corresponds to about half a liter of diesel oil. The net calorific value depends on the efficiency of the burners or appliances. Methane is the valuable component under the aspect of using biogas as a fuel.
Biogas is produced through an anaerobic digestion by anaerobic bacteria with four steps identified as: hydrolysis, acidification, production of acetate and production of methane using a microorganism consortium. The final product is a gas mixture composed mainly of methane and carbon dioxide and traces of hydrogen sulfide, ammonia, hydrogen, and carbon monoxide.
Anaerobic digestion has demonstrated to be a flexible technology with a variety of reactor designs adapted to many situations, transforming liquid and solid residual organic matter to valuable intermediates such as carboxylates, which can be recovered, and finally to biogas, which can be used for the production of heat and electricity or upgraded to biomethane.
Current policies favor biogas production as an energy source, for biomethane or electricity. The anaerobic digestion is a key technology to prepare the transition to a new energy and a bio- based circular economy paradigm.
Abstract.
2021-01-01T00:00:00ZSunflower oil oxydation into forced thermal processesDRUŢĂ, RaisaDUCA, GheorgheSUBOTIN, Iuriehttp://repository.utm.md/handle/5014/177672021-10-18T12:03:18Z2021-01-01T00:00:00ZSunflower oil oxydation into forced thermal processes
DRUŢĂ, Raisa; DUCA, Gheorghe; SUBOTIN, Iurie
The work investigated the processes that take place during the forced thermal oxidation of sunflower oil. The results obtained in the study showed a major impact of thermo-oxidation (90 ± 2 °C).
The supplied air with a speed of 8 ÷ 10 L h-1 for 50 hours) influences physico-chemical indicators of the studied oil. Acidity index of fresh sunflower oil increased 13.7-fold, with a value of 2.46 mg KOH/g-1 fat for thermo-oxidized oil compared to the initial value of 0.188 mg KOH g- 1 fat. Thermo-oxidation of sunflower oil caused a significant decrease in the saponification index, which indicates a significant increase in degree of polymerization and leads to an increase in the viscosity of the studied sunflower oil.
To highlight the impact of heat treatments, the analysis was performed by IR spectroscopy and possible mechanisms of forced oxidation of unsaturated fatty acids under the influence of thermal factor were analyzed. It was established that the application treatment favored both the formation of carbonyl secondary compounds and simultaneous formation of hydroperoxides and triglycerides containing hydroxylated groups. Accumulation of hydroperoxides and triacylglycerides that have hydroxyl functions facilitated the course of polymerization reactions, which are to increase the viscosity of thermo-oxidized sunflower oil. Formation during thermo- oxidation of trans-isomers of polyunsaturated acids led to the appearance of the group = CH, with deformation vibration band at 966 cm-1 in the spectrum of thermo-oxidized oil. Simultaneously, there was a slight reduction in the intensity of the deformation vibration of the group = CH, with band at 1098 cm-1 at the respective cis isomer of polyunsaturated acids.
Abstract.
2021-01-01T00:00:00ZApplication of nanocomposites to grape wastes processing for improve biodiesel productionSTEGARESCU, AdinaSORAN, Maria-LoredanaLUNG, IldikoOPRIŞ, OcsanaGUŢOIU, SimonaPANĂ, Ovidiu-Ioanhttp://repository.utm.md/handle/5014/177662021-10-18T11:56:45Z2021-01-01T00:00:00ZApplication of nanocomposites to grape wastes processing for improve biodiesel production
STEGARESCU, Adina; SORAN, Maria-Loredana; LUNG, Ildiko; OPRIŞ, Ocsana; GUŢOIU, Simona; PANĂ, Ovidiu-Ioan
Biodiesel production has received a special attention in the recent years due to its advantages in the conservation of the fossil fuels and production is becoming more and more important. Different methods for production are tested. Biodiesel can be obtained from different vegetable oils or animal fats and can be a natural substitute for petroleum-based fuels, with the similar or sometimes even higher properties. In plus, it is renewable, biodegradable and nontoxic. For socioeconomic reasons, edible oils used for biodiesel production should be replaced with other sources with lower costs like is the oil obtained from grape wastes, since over 20% of grape becomes waste during the production of wine.
Material and methods. The oil obtaining from seeds and grape residues was prepared according to the method previously published by our group [1]. Fe3O4/MnO2 (FOM 1-4) nanocomposites were synthetized using a modified experimental procedure presented by Shu and Wang in 2009 [2].
Results. Fe3O4/MnO2 nanocomposites prepared in this study were obtained both by chemically route and also using oregano extract, but the highest surface area and the best magnetic properties were obtained for FOM1. The selected Fe3O4/MnO2 nanocomposites were further tested for microwave assisted transesterification of grapes residues and seeds oil. For all tests using FOM1 as catalyst, the resulted FAME’s mixture mostly consists of C18:2, obtaining promising preliminary results. The highest quantity of linoleic acid was obtained by microwave treatment for 15 min at 800 W.
Conclusions. The Fe3O4/MnO2 nanocomposites with the highest specific surface area from all prepared nanocomposites were tested for microwave-assisted transesterification studies. These nanocomposites, used as catalyst, determine an increasing reaction rate of the transesterification process thus being a promising route for biodiesel production.
Abstract.
2021-01-01T00:00:00ZThe possibility and necessity to production of tartaric acid in Republic of MoldovaMUSTEAŢĂ, GrigoreBALANUŢĂ, AnatolSCUTARU, IurieCOVACI, EcaterinaSCLIFOS, AlionaARHIP, Vasilehttp://repository.utm.md/handle/5014/177652021-10-18T11:48:03Z2021-01-01T00:00:00ZThe possibility and necessity to production of tartaric acid in Republic of Moldova
MUSTEAŢĂ, Grigore; BALANUŢĂ, Anatol; SCUTARU, Iurie; COVACI, Ecaterina; SCLIFOS, Aliona; ARHIP, Vasile
The wine industry has been and is a source of tartaric acid in wine technology. The main wastes from which are possible to obtain tartaric acid: grape marcs, yeast, vinasa, wine stone, sediments from cold treatment.
But the use of this waste are limited only to the production of tartaric acid lime (calcium tartrate) and wine stone, which were shipped to Ukraine and Armenia where the finished product is obtained tartaric acid, as well as some salts of this acid.
At the present, tartaric acid is used in considerable quantities in winemaking and the food industry, being a rather expensive import product.
The Department of Oenology and Chemistry has developed a complete technological scheme for the use of wine waste with the obtaining of the finished product - tartaric acid.
For the country's economy the implementation of propose tartaric acid production in the Republic of Moldova has an essential significance. It does not require large investments. The wineries can also participate in the organization of tartaric acid production by supplying calcium tartrate, wine stone, and sediments from cold wine stabilization, which will provide the necessary amount of this acid.
Abstract.
2021-01-01T00:00:00Z