1,721,045 research outputs found
Co-composted biochar (Combi) production and its effects on ocimum basilicum plants growth
No full textIn agriculture, in recent years, more and more attention has been given to the COMBI. COMBI is a soil improver obtained from a composting process of organic material with biochar, added at the beginning of the process itself. Biochar has been used for several years and many studies have shown the benefits it brings when applied to soils, while COMBI is still little studied. This article aims to demonstrate both the effects of COMBI on the growth of Ocimum basilicum specie plants and to quantify the best quantity to be applied within the substrate. The experimental trials were performed in a greenhouse with controlled temperature and humidity, according to the following growth tests theses: Control: Soil for gardens composed mainly of peat (CTRL); thesis 1: Soil mixed with COMBI at 10% v/v (COMBI10); thesis 2: Soil mixed with COMBI at 20% v/v (COMBI20); thesis 3: Soil mixed with COMBI at 40% v/v (COMBI40); thesis 4: Soil mixed with COMBI at 80% v/v (COMBI80); thesis 5: 100% COMBI (COMBI100). The results showed good growth of basil plants in the COMBI10 and COMBI20 cases, compared to the control. COMBI80 and COMBI100 theses, on the other hand, did not lead to positive results; in particular COMBI100 did not allow either seeds germination in most cases. To compare the quality of the basil plants, the total amount of essential oil for CTRL, COMBI10, COMBI20 and COMBI 40 theses was extracted and quantified
Equilibrium modeling of hemp hurd gasification
No full textThe aim of this work is modeling a gasification process where a non-conventional biomass is used as fuel: Hemp hurd residues. An equilibrium model of the gasification reaction was implemented in the PhytonTM software environment. Syngas composition, syngas higher heating value, tar production and gasification cold gas efficiency were evaluated at different value of biomass moisture starting from biomass ultimate analysis and reaction equivalence ratio (ER) value. The model is able to predict char and tar production as function of biomass composition, moisture and ER. A comparison with experimental data obtained from hemp hurd gasification was done to validate equilibrium model results. Gasification tests were performed using a low capacity lab-scale gasification reactor designed to use about 1 kg per hour of dry biomass fuel. Results show small errors between model results and experimental result. Several simulations were performed to assess the gasification dependency on selected boundary conditions like biomass moisture and ER of the gasifier
Implementation of a portable petrol - powered generator fueled through a tabletop biomass gasifier
No full textPortable petrol powered generator are very popular around the world. They are used mostly when electrical power from the grid is not available, for example in blackout scenarios, remote areas or for temporary use and they are basically irreplaceable in many cases. The idea behind this work is to substitute the fossil fuel as the energy source of these systems with the syngas produced through biomass gasification, that is a carbon negative energy process in order to achieve a complete decarbonisation as soon as possible. Coupling gasifiers and reciprocating internal combustion engine is a very old technology, however there are no small and cheap systems available that can be successfully connected to this kind of generator. The laboratory scale gasifier presented in Lisbon at the 27th EUBCE in the paper titled: “Design and first tests of a micro lab scale (2kg/h) gasifier” after a series of test has been improved enhancing its efficiency, gas quality and power output. A GeoTech GGP 4000 ES petrol powered has been selected to operate with the syngas from the gasification system and its intake manifold has been modified. The gasifier is able to operate with different kinds of biomasses like wood fir pellets, wood chips, vine prunings pellets, hemp hurd etc. The fuel chosen for the test was the standard A1 ENPlus wood pellet. An Iveco air filter was used to preserve the engine from the tars and particulate present in the gas. The energetic consumption was calculated and the thermal power output from the engine exhaust was estimated measuring gas composition and the air flow and entering in the gasifier. The results from the test show that it is possible renew the way the portable petrol generator are used, making them efficient and eco-friendly without increasing dramatically the complexity of the system or the costs
Implementation of engine exhaust gas recirculation in a fixed bed gasification reactor
No full textThis study aims to increase the energy efficiency of a micro combined heat and power (micro-CHP) system able to produce electrical energy and thermal energy from wood biomass through the gasification process and an internal combustion engine. Since nowadays the engine exhaust gas is released in the atmosphere, without being exploited, the goal is to recover this gas. A fraction of gas is taken from the engine exhaust pipe and is reinserted in the gasification reactor head to provide thermal energy and a series of new reagents: A sort of exhaust gas recirculation (EGR) is created. Some tests were carried out at different fractions of EGR, 10% and 20%, on a Power Pallet 30 system (PP30) built by All Power Labs, to obtain information about syngas quality and gasification efficiency. The gas high heating value (HHV) is indirectly determined by gas chromatography that gives the syngas composition and the concentration of single compounds. The results show an increment of the nitrogen content and a reduction of hydrogen in the syngas when the EGR percentage rising. The concentration of the other gases does not change. This variation causes an HHV drop, compared to the case without EGR, which is reflected in the PP30 efficiency. Tests have revealed an increment of efficiency from 70% to 71% only in the case with EGR sets at 20%, thanks to the higher temperature at which the exhaust gas was reintroduced in the gasifier head, compared to the reactor temperature itself, that leads to an increase of syngas flow rate. Therefore, an higher gasifier efficiency has been obtained although the drop of heating value, thanks to the larger production of syngas. This higher volume of produced syngas not only can compensate the HHV drop but also bring benefit to the PP30, compared to the case without EGR. Consequently, the temperature is more important than the flow rate value or the composition of the exhaust gas reintroduced in the head of the gasifier. Taking into account the low cost of the recirculation circuit components, the EGR is a good improvement for the fixed bed gasification reactors
UTILIZATION OF GASIFICATION BIOCHAR FOR THE REDUCTION OF GREENHOUSE GASES AND AMMONIA EMISSIONS IN SWINE SLURRY STORAGES
No full textCircular economy, sustainability in agriculture, reuse of by-products, reduction of waste, reduction of emissions, improvement of plant efficiency and exploitation of resources are among the main objectives contained in the 2030 United Nations Agenda. Since this virtuosity often also brings a significant reduction of costs, the market increasingly requires this “circular approach”. This study aims to reduce greenhouse gas emissions (methane and nitrous oxide) and ammonia from swine slurry when it is stored in tanks or lagoons. The study investigates the reduction of emissions through the application of gasification biochar, a low-density and high-porosity material, able to interact, physically and biologically, with thepig slurry. To evaluate the best methodology, three different theseswere investigated: a 5 cm biochar floating layer on the surface of the slurry; filter biochar cartridge crossed by the slurry; nitrifying-denitrifying system in which biochar is used as substrate for micro-bacterial growing colonies. A control thesis, without biochar, was also installed. Three experimental campaigns of two months each (winter, spring, and summer measurements campaigns) were carried out during which greenhouse gases, ammonia and odor emissions were monitored every ten days. Biochar, recognized to date as soil improver, once applied to the pig slurry lagoon can bedistributed on fields. This study investigates, in fact, also the improved agronomic biochar characteristics obtained thanks to the micro and macro nutrients adsorbed or bound to the grains after the biochar slurry contact. This work evaluates the environmental sustainability of the biochar application in slurry treatments. Moreover, reduction of emissions from the storages, increase of stable carbon and nutrient elements in the soil after the application of slurry-biochar mix and economic feasibility of the treatments are investigated, to be able to carefully evaluate the scaling up and the industrial application of these technology. The results identify the biochar as atreatment that can be used for the reduction of greenhouse gases and ammonia emission from swine manure storage lagoon. In particular, the best results were obtained with biochar used as a substrate for microbial colonies. The results showed, in fact, that the nitrifying/denitrifying treatment is the more promising application, compared to the other two tested methodologies. From the chemical analysis performed on the biochar, of all three theses, it was confirmed that the biochar can be used as a soil improver and can be applied to the soil as nitrogen and phosphorus rich amendment
Enhanced heat transfer in tubes-in-shell heat exchanger for syngas cooling: A comparison between conventional and perforated twisted tape inserts
No full textIn this work, twisted tape inserts were applied to a tube-in-shell heat exchanger for syngas cooling. A comparison between plain tube, standard full twisted tape and perforated twisted tape was carried out by measuring the thermal-hydraulic performance and the heat dissipated. Results shown a considerable increase of heat transfer using twisted tapes for syngas cooling and perforated twisted tapes performed better than full twisted tapes, reaching a thermal-hydraulic efficiency of 1.24 and increasing the Nu number up to 47% respect of the plain tube. Perforated twisted tapes confirmed the literature results even applied to syngas cooling and are of great interest as heat transfer enhancers to reduce the heat exchanger dimensions, key parameter for micro-scale gasification power plants
EVALUATION OF METHANOL PRODUCTION FROM HEMP BIOWASTE GASIFICATION
No full textAim of this work is to estimate the methanol production from hemp market by-products through a combination of experimental tests and chemical equilibrium models. Three types of byproducts are investigated: chipped hemp hurd, cut hemp stalks and pelleted hemp stalks blended with 50% wt. of wood sawdust. The fuels prepared are then tested in a table-top air blown gasifier with a nominal consumption of 2 kg/h of biomass. The gasifier has a downdraft Imbert architecture and it is monitored using a combination of gas totalizers, thermocouples and a micro-gas chromatograph. Knowing biomass composition and consumption, gasification air and syngas flow rates and composition, an evaluation of the gasifier cold gas efficiency is performed. Data about syngas compositions are then used to simulate a methanol conversion using an equilibrium model. Methanol (CH3OH) is an important feedstock for the production of transport fuels and chemicals. I.e. example, the production of gasoline from methanol is an established commercial process. Methanol is produced through the synthesis of syngas in the presence of catalysts. In this work, low pressure Methanol synthesis reaction is simulated (5 MPa, 220°C). Results from syngas to methanol conversion were used to calculate methanol to biomass yield
Fouling effect in a shell-and-tube heat exchanger with twisted tape inserts applied to a small-scale biomass gasification power plant
Full text linkIn this work the over-time behaviour of a shell-and-tube type heat exchanger applied to a commercial and small-scale wood biomass gasification system was investigated. The heat exchanger, equipped with twisted tape turbulators, was used to cool down the syngas produced by the power plant. An experimental campaign was conducted to evaluate the performance trend in the first 15 hours of operation. The results showed an increase in heat transfer which led to a progressive reduction of the gas outlet temperature from 105.4 °C to 90.0 °C. The data collected confirm the literature studies on the positive effect that the deposits of particulate matter and tars have in reducing the clearance between the heat exchanger pipes and the turbulators, providing information for the temporal optimization of the cleaning strategy of the heat exchanger itself
Seeking the synergistic potential of biochar integration in municipal composting plants for techno-economic and environmental leverage
No full textThis work comprehensively investigates the technological, economic, and environmental implications of biochar application to a municipal composting facility through various combinations of in situ gasification or biochar trading. The aim is to find the optimal solution to minimize environmental impacts and to maximize resource utilization over the year. The study hybridizes an existing composting facility using various gasification plants chosen in between the commercial SynCraft model, resulting in a pioneering study where a gasifier is integrated in a composting plant. The techno-economic feasibility of each scenario is obtained calculating the payback time, estimating the annual biomass demand, evaluating the seasonal variability of biomass, and setting as a key-point the amount of produced electrical energy and gasification biochar. The scenarios differ in the installed gasifier sizing (500 kW, 1 MW and 1.7 MW) and the supplementary amount of biochar that may be purchased, applied at a 3 % w/w rate on the treated organic mix. Economic results reveal that a purchase of all necessary biochar is infeasible; therefore, the installation of a gasifier for biochar self-production should be always considered. For the 500-kW gasifier a 25-year payback (weighted average cost of capital = 10 %) that reduces to 14 or 12 years for the 1 MW gasifier, respectively with and without purchase of supplementary biochar. The 1.7 MW gasifier is the most cost-effective option, but it requires high initial investments. Additionally, this work studies both the carbon dioxide equivalent storage, thanks to the biochar utilization, quantifying the corresponding Carbon Credits in 3652 credits for the best scenario (through VERRA method), and the reduction of methane emissions during composting that are abated by nearly half in the best scenarios. Aiding biochar into composting operations emerges as a promising way for waste management optimization, balancing economic viability and environmental sustainability. On the other hand, some operational issues are identified and discussed in this work, but the findings highlight the significance of innovative approaches in shaping the future of composting facilities and advancing the circular economy
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