1,721,044 research outputs found
Micro Scale Slow-Pyrolysis Rotary Kiln for Syngas and Char Production From Biomass and Waste: Design and Construction of a Reactor Test Bench
No full textSlow pyrolysis of waste and biomass may represent an interesting solution for renewable energy conversion in highly regenerative Gas Turbine (GT) or Internal Combustion Engines (ICE) based power cycles. The combined production of a medium LHV gas to fuel the GT or the ICE and of a high LHV byproduct (tar and/or char) that may contribute to maintain the pyrolysis process, makes pyrolysis highly competitive when compared to gasification. Nevertheless few
simulations of such integrated plants are available in literature also because of the lack of general and robust modeling tools for the pyrolysis process. A pilot scale rotary kiln pyrolyzer was built at the University of Perugia to investigate the main benefits and drawbacks of the technology. The pyrolyzer will provide the experimental data that are necessary both to evaluate mass and energy balances, and to support the pyrolysis simulation activity that the authors are carrying out. Namely the test rig will provide, for each given quantity and composition of the biomass or
waste in input, the gas, char and tar yields and compositions and the energy provided to maintain the process. This paper describes the main features and operational possibilities of the plant
Integrated Micro-Turbine and Rotary-Kiln Pyrolysis System as a Waste to Energy Solution for a Small Town in Central Italy: Cost Positioning and Global Warming Assessment
No full textSolid waste, and bio-residuals in general, are usually disposed of or alternatively converted into energy by means of medium to big scale power plants. For isolated communities, usually in protected natural areas, this turns into high energy and waste management costs because of their intrinsic distance from landfills and power plants. Considering also the electric dependency from the grid, small towns are commonly showing low sustainability. This paper
focuses on both problems by evaluating the economic feasibility and the global warming contribution of an innovative micro scale waste to energy system based on a microturbine fuelled by waste pyrolysis gas. The plant reaches high efficiency, considering the scale, because of its high regenerative rate and is tailored to the waste disposal needs of Giano Dell'Umbria a small town in central Italy. The economic analysis was carried out, with the Net Present Value method, to determine the expected capital cost of the plant considering that the innovative technology utilized does not allow a reliable cost evaluation. The global warming contribution was calculated considering CO2 and CH4 avoided emission from landfilling and the better CO2 emission rate of such a technology with respect to the status quo. Results obtained show an acceptable cost positioning for the plant that makes it an interesting solution for distributed waste to energy systems. Executive projecting and construction of the
proposed technology was funded and a pilot plant will be built and tested in 2002, in a laboratory facility of the University of Perugia
An IPRP (Integrated Pyrolysis Regenerated Plant) Microscale Demonstrative Unit in Central Italy
No full textThe Integrated Pyrolysis Regenerated Plant (IPRP) concept is based on a Gas Turbine (GT) fuelled by pyrogas produced in a rotary kiln slow pyrolysis reactor; pyrolysis process by-product, char, is used to provide the thermal energy required for pyrolysis. An IPRP demonstration unit based on an 80 kWE microturbine was built at the Terni facility of the University of Perugia. The plant is made of a slow pyrolysis rotary kiln pyrolyzer, a wet scrubbing section for tar and water vapor removal, a micro gas turbine and a treatment section for the exhaust gases.
This paper describes the plant layout and expected performance with different options for waste heat recovery
IPRP: Integrated Pyrolysis Combined Plant — An Efficient and Scalable Concept for Gas Turbine Based Energy Conversion From Biomass and Waste
No full textA massive effort towards sustainability is necessary to prevent global warming and energy sources impoverishment: both biomass and waste to energy conversion may represent key actions to reach this goal. At the present State Of the Art (SOA) available technologies for biomass and waste to energy
conversion are similar and include low to mid efficiency grate incineration or fluidised bed combustion with steam power cycles or mid to high efficiency Gas Turbine based cycles through integrated gasification technology. Nevertheless these
plants are all available from mid-to-high scale range that can be highly intrusive on protected areas and socially unacceptable. This paper proposes an innovative, low cost, high efficiency plant in which the residue is gasified in absence of oxygen (pyrolysis), in a rotary kiln, by means of a highly regenerative gas turbine based cycle. Pyrolysis is preferred to gasification, because the syngas obtained has a
higher LHV and produces char or tar as a by-product with an interesting energy content to be re-utilized inside the cycle. Different plant configurations are proposed and discussed through principal thermodynamic variables parametric analysis. Results show that very interesting efficiencies are obtainable in the 30%–40% range, at every scale range therefore presenting an interesting alternative especially to small size (below 5 MW) grate incineration and steam power plant technology. Moreover, the IPRP plant provides a unique solution for micro-scale (below 500 kW) power plants, opening a new and competitive possibility for distributed biomass or waste to energy conversion systems where low environmental and social impact turns into higher interest and positive dissemination effect
Evaluation of Available Technologies for Chicken Manure Energy Conversion and Techno-Economic Assessment of a Case Study in Italy
No full textChicken manure used as a natural fertilizer, given its high Nitrogen content, requires key actions in odor control that are often difficult to carry out resulting in an image loss for the company. Manure land-filling however is costly as well as incineration and this latter does still require odor control. Energy conversion from chicken manure may turn the cost into an earning that could payback both the investment and the image loss for odorous emissions. In this optic the paper analyses the different technologies that are available for energy conversion from chicken manure namely incineration, gasification, pyrolysis and anaerobic digestion with application to a real case. A large scale egg selling company in central Italy, with three production sites, was selected and its mass and energy flow balance assessed with particular
reference to manure production and electricity consumption and expense. Five different technologies were then considered for energy conversion from chicken manure both for a single production site (microscale) and for the three (small scale). Grate incineration with steam production from exhaust gases was considered and discarded because of the
too small scale. BTG gasification technology and IPRP pyrolysis technology presented by the authors, were evaluated and the techno-economic assessment showed interesting pay back time with medium to high investment costs and medium efficiencies.
Pyrolysis technology with gas-steam combined cycle was considered but the economics show a very high pay back for the investment due to the small scale.
Finally anaerobic digestion was evaluated showing the lowest investment cost and efficiency but an interesting payback period also considering that no public financing was considered. This latter solution has been presented to the company that will decide whether to finance the project
Thermodynamic Analysis and Possible Applications of the Integrated Pyrolysis Fuel Cell Plant (IPFCP)
No full textBiomass and waste are generally considered as a very promising option for fossil fuel substitution and greenhouse effect reduction in a sustainable energy scenario. This paper examines the possible lay-out and performance of an innovative energy system based on the integration of a high temperature fuel cell with a pyrolysis reactor. The pyrolyzer converts biomass or solid waste into syngas, which is cleaned from impurities and feeds a Solid Oxide Fuel Cell (SOFC), operating at 1000°C. A combustor supplies the energy required for pyrolysis, burning the solid
and liquid fraction of the pyrolysis yield, as well as the un-oxidized fuel leaving the cell anode. Literature data have been used for determining pyrolysis yield as a function of reactor temperature and evaluating its effect on the plant thermodynamic efficiency. The coupling of the system to a gas turbine using the fuel cell as its combustion chamber is also evaluated. Results show that very interesting efficiencies are obtainable in the 20%–30% range
CFD Analysis of an Annular Micro Gas Turbine Combustion Chamber Fuelled With Liquid Biofuels: Preliminary Results With Bioethanol
No full textLiquid biofuels, such as bioethanol, biodiesel and vegetal oils, can effectively be used in internal combustion engines blended with liquid fuels of fossil origin or in their substitution, allowing a reduction of CO2 and pollutant emissions in the atmosphere. This work is supported by a CFD analysis to study the feasibility of using these fuels derived from biomass in a 80 kWel micro gas turbine, originally designed for operation with natural gas. In this paper preliminary results about the behavior of bioethanol in the MGT combustion chamber are presented. The complete investigation however includes biodiesel and also glycerin, a byproduct of biodiesel production. To carry out the computational simulations, combustion models included in a commercial software and oxidation mechanism of ethanol taken from the literature were used. The geometry of the NG injector was modified to optimize the liquid inlet into the combustor. Simulation results in terms of temperatures, pressures, and emissions were compared with data available for natural gas combustion in the original combustion chamber
Rotary Kiln Slow Pyrolysis for Syngas and Char Production From Biomass and Waste-Part II: Introducing Product Yields in the Energy Balance
No full textA microscale electrically heated rotary kiln for slow pyrolysis of biomass and waste was designed and built at the University of Perugia. The reactor is connected to a wet scrubbing section, for tar removal, and to a monitored combustion chamber to evaluate the lower heating value of the syngas. The system allows the evaluation of gas, tar and char yields for different pyrolysis temperature and residence time. The feeding screw conveyor and the kiln are rigidly connected; therefore a modification of the flow rate implies a modification of the inside solid motion and of residence time. Part I of the paper describes the theoretical and experimental evaluation of the working envelope of the reactor that is, rotational speed as a function of feedstock density and humidity content, to obtain pyrolysis conditions inside the kiln. This paper describes the development and resolution of an energy balance of the reactor under pyrolysis conditions. Once the rotational speed n is fixed, the aim of the balance is to obtain the yield of wood biomass pyrolysis products such as syngas, tar and char Results can be used to choose the correct rotational speed of kiln and feeding screw before doing the real pyrolysis test
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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