Bruno D’Alessandro

Integrated Pyrolysis Regenerated Plant (IPRP): An Efficient and Scalable Concept for Gas Turbine Based Energy Conversion From Biomass and Waste

A 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 available technologies for biomass and waste to energy conversion are similar and include low to mid efficiency grate incineration or fluidized 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 the 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 low heating value 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 for every plant scale. This fact shows how IPRP technology can provide an interesting alternative to traditional technologies, especially for the small size (below 5MW). Moreover, the IPRP technology provides a unique solution for microscale (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.

Gas Turbines CHP for Bioethanol and Biodiesel Production Without Waste Streams

In the context of the recent decision of the European Commission to incorporate a minimum of 10% biofuel by 2020 in total transport fuel use, the production of bioethanol and biodiesel will be boosted. When compared to fossil fuels this two biofuels have numerous advantages i.e. they are renewable, they run in conventional vehicles, they are not toxic, they are biodegradable, they show low particulate emissions and they are CO2 neutral. However they show some disadvantages such as the high energy demand of their production and the high yield of byproducts (i.e. glycerin for biodiesel and distiller’s waste for bioethanol), that require a dedicated marketing effort and supply chain. The energy demand required for the production of both biodiesel, through transesterification of vegetal oils, and bioethanol, through fermentation followed by distillation, is thermal and mechanical and can be satisfied by means of a CHP plant integrated in the production line fueled by its own byproducts. The paper analyzes the energy balances of two CHP plants fed with the above mentioned wastes (glycerin and wheat straw residues) and integrated in the biofuels (respectively biodiesel and bioethanol) production plants. The CHP plant considered are based on the IPRP (Integrated Pyrolysis Regenerated Plant) technology, meaning a gas turbine fed with syngas obtained from slow pyrolysis of the residues. Results show that in the case of biodiesel the production of glycerine is sufficient to satisfy the electricity demand of the plant that is lower than the heat demand, while the last cannot be completely covered because glycerine production is reduced respect to the input mass of vegetable oil and equal to 10% w/w. Concerning bioethanol, wheat straw residues are enough to cover heat demand that is the most important energy input of the process but they are not able to cover electricity input that is linked with the milling of the raw material. This is because of the reduced syngas yields and its lower energy content if compared with that obtained using glycerine.Copyright

Performance Evaluation of the IPRP Technology When Fueled With Biomass Residuals and Waste Feedstocks

The Integrated Pyrolysis Regenerated Plant (IPRP) concept is based on a rotary kiln pyrolyzer that converts biomass or wastes (BW the combustion of pyrolysis by-products (char or tar), is used to provide heat to the pyrolyzer together with the GT exhaust gases. The IPRP concept was modelled through an homemade software, that utilizes thermodynamic relations, energy balances and data available in the Literature for BW pyrolysis products. The analysis was carried out investigating the influence on the plant performances of main thermodynamic parameters like the Turbine Inlet Temperature (TIT), the Regeneration Ratio (RR) and the manometric compression ratio (β) of the gas turbine; when data on the pyrolysis process where available for different pyrolysis temperature, also the different pyrolysis temperature (TP ) was considered. Finally, data obtained from the analysis where collected for the typical parameters of different GT sizes, namely the manometric compression ratio and the turbine inlet temperature. For the other parameters, where considered the ones that give the highest efficiencies. The paper shows the IPRP efficiency, when fuelled with different biomass or wastes materials and for different GT (plant) size.Copyright

Assessment of the Energy Conversion of Whole Oil Fruits With a Pyrolysis and Gas Turbine Process

Crude vegetable oil energy conversion is addressed as an important issue for the electric energy production without changing the CO2 concentration in atmosphere. The oil is obtained by grinding oily fruits while a high amount of energy rich residues is produced. The present paper evaluates the thermodynamic and environmental performances of a plant that converts the whole fruit into energy through pyrolysis. Vegetable Oil is used to fuel an internal combustion engine while solid residuals of the oil production are used to fuel an Integrated Pyrolysis Regenerated Plant (IPRP) technology based plant. Tars from pyrolysis process are water scrubbed from syngas and then emulsioned with vegetable oil to increase the electric energy production. IPRP concept is based on a gas turbine (GT) fuelled with the syngas produced in a rotary kiln pyrolyzer fed with Biomass or Wastes (BW GT exhaust gases together with combustion of pyrolysis by-products (char), is used to sustain the pyrolysis process. The IPRP concept was modelled through thermodynamic relations, energy balances and data available in the Literature for oil yields and husks pyrolysis products. The analysis was carried out investigating the influence on plant performances of main thermodynamic parameters of the GT and on pyrolysis temperature. Results are collected for typical parameters of different GT sizes, namely the manometric compression ratio and the turbine inlet temperature. The paper discusses best efficiency points of different plant sizes when fuelled with syngas and tar and oil for three important oil fruits namely sunflower, palm and soybean.Copyright

An IPRP (Integrated Pyrolysis Regenerated Plant) Microscale Demonstrative Unit in Central Italy

The 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.Copyright

Experimental and CFD Evaluation of the Part Load Performance of a Micro Gas Turbine Fuelled With CH4-N2 Mixtures

There is a strong interest in numerical and experimental research on syngas combustion in GTs however experimental studies require syngas generation which is costly and also provides a variable and dirty fuel gas. To investigate the combustion behaviour and GT performance when fuelled with low LHV syngas, nitrogen diluted natural gas can be considered.To this aim the micro gas turbine (mGT) available at the IPRP (Integrated Pyrolysis Regenerated Plant) pilot facility of the University of Perugia, modified to use biomass pyrolysis gas, was fuelled with a CH4−N2 mixtures at different part load conditions obtained from pipeline (CH4) and cylinders (N2). The aim of the work is to analyze the functioning condition of the mGT which is monitored by a dedicated data acquisition system. Performances are evaluated and discussed showing that nitrogen dilution does not affect significantly efficiency and NOx production while CO emission increase slightly when increasing nitrogen content and this is more evident when decreasing the load.A CFD model of the combustion chamber, which was developed and tuned in previous works by the authors, was also run to reproduce experimental data showing a good agreement and also suggesting flame detachment in the mixing tube when nitrogen is present.© 2012 ASME

Numerical Analysis of the Use of Vegetable Oil-Tars Mixtures From Syngas Scrubbing in a Microturbine Combustor

TARs are a mixture of heavy and light hydrocarbons produced from pyrolysis and gasification of biomass and waste, as condensable volatiles in the syngas. Given their relatively low dew point, they are usually removed from syngas to avoid condensation and fouling of engines and equipment. Vegetable oil scrubbing compared to water scrubbing yields oil tar mixtures which is a renewable fuel and may be useful successfully to power a gas turbine. The feasibility of burning TAR, blended vegetable oil, in a combustor of a turbine is investigated. Computational simulations with a CFD software were performed to analyze evaporation and combustion processes of vegetable oil-tars mixture compared with pure vegetable oil and diesel, in terms of residence time, temperature distributions, inlet turbine conditions.The results show difficulties in evaporation of both vegetable oil and vegetable oil-tar mixture compared to diesel, with consequences in the combustion in terms of temperature distributions and higher NOx emissions. Preheating of vegetable oil and vegetable oil-tar mixture improves their evaporation approaching the results to those of the diesel case.Copyright

Evaluation of Available Technologies for Chicken Manure Energy Conversion and Techno-Economic Assessment of a Case Study in Italy

Chicken 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.© 2004 ASME

Improving lifetime and manufacturability of an RQL combustor for microturbines: design and numerical validation

A new annular RQL combustion chamber of an 80 kWel Elliott TA80R micro gas turbine was designed and built with a modified geometry to overcome known failures at low running hours (around 2500 hrs) caused by overheating. Design considered simplified manufacturability and flow optimization to reduce emission while maintaining similar temperatures and efficiencies. A preliminary geometry was analyzed and also built to verify manufacturability and economics. It was easily built with overall brute costs around 3000 €. It has also run continuously for over 27.000 hrs.An optimized geometry, however, guaranteed similar TIT with respect to the original geometry with a considerable reduction in CO and NOx emissions.Given the installation of the mGT at the IRP (Integrated Pyrolysis Regenerated Plant) the modified geometry was tested through CFD analysis on syngas from biomass thermochemical processes. The results show that further modifications of the liner are required for optimal operation and to reach adequate values for Turbine Inlet Temperature.© 2015 ASME

IPRP: Integrated Pyrolysis Combined Plant — An Efficient and Scalable Concept for Gas Turbine Based Energy Conversion From Biomass and Waste

A 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.Copyright