Pietro Bartocci

Thermogravimetric analysis of the behavior of sub-bituminous coal and cellulosic ethanol residue during co-combustion.

The influence of the addition of cellulosic ethanol residue (CER) on the combustion of Indonesian sub-bituminous coal was analyzed by non isothermal thermo-gravimetric analysis (TGA). The effect of blends ratio (5%, 10%, 15% and 20%), interaction mechanism, and heating rate (5°C/min, 10°C/min, 15°C/min, 20°C/min) on the combustion process was studied. The results show that the increase of the blending ratio allows to achieve the increase of the combustibility index from 7.49E-08 to 5.26E-07 at the blending ratio of 20%. Two types of non-isothermal kinetic analysis methods (Ozawa-Flynn-Wall and Vyazovkin) were also applied. Results indicate that the activation energy of the blends decreases with increasing the conversion rate. In particular, the blending ratio of 20% confirms to have the better combustion performance, with the average value of the activation energy equal to 41.10 kJ/mol obtained by Ozawa-Flynn-Wall model and 31.17 kJ/mol obtained by Vyazovkin model.

Rotary kiln slow pyrolysis for syngas and char production from biomass and waste -Part II Introducing product yields in the energy balance

A 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.

Rotary Kiln Slow Pyrolysis for Syngas and Char Production From Biomass and Waste—Part I: Working Envelope of the Reactor

A 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 temperatures and residence times. 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. The paper provides the theoretical and experimental calculation of the relationships between residence time and flow rate used to determine the working envelope of the reactor as a function of the feedstock bulk density and moisture content, given the actual heat rate of the electric heaters. The methodology is extendable to any rotary kiln reactor with a rigidly connected feeding screw conveyor, given its geometric and energetic specifications. Part II of the paper will extend the energy balance, also introducing the yields of pyrolysis products.

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

Biochar pellet carbon footprint

Life cycle assessment of Biochar was performed in this study using SimaPro software, aiming at the evaluation of the carbon footprint of biochar. Product Category rules have been developed. Data have been collected in a demonstrative slow pyrolysis plant, which is present at the University of Perugia and from field tests. The technical standard followed is ISO/TS 14067. Biochar, used as a soil amendment can improve soil health and fertility, soil structure, nutrient availability, soil-water retention capacity and is also a mechanism for long term Carbon storage in soils. Carbon sequestration in soils can be seen not only as a strategy to mitigate the global climate change, but also as a source of profit for companies via Carbon Credits. LCA is a useful tool to estimate the Carbon balance through all the Biochar life cycle. The feedstocks considered in this study is miscanthus, a perennial herbaceous energy crop. The functional unit is one ton of dry matter of initial feedstock (that is miscanthus biomass). The final carbon footprint is equal to -737 kgCO2eq/t of feedstock dried.

Rotary Kiln Slow Pyrolysis for Syngas and Char Production From Biomass and Waste: Part 1 — Working Envelope of the Reactor

A micro scale 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 scrubbing section, for tar removal, and to a monitored combustion chamber to evaluate the LHV 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. The paper provides the theoretical and experimental calculation of the relationships between Residence Time and Flow Rate used to determine the working envelope of the reactor as a function of the feedstock bulk density and moisture content, given the actual heat rate of the electric heaters. The methodology is extendable to any rotary kiln reactor with a rigidly connected feeding screw conveyor, given its geometric and energetic specifications. Part 2 of the paper will extend the energy balance introducing also the yields of pyrolysis products.Copyright

Thermal degradation of driftwood: Determination of the concentration of sodium, calcium, magnesium, chlorine and sulfur containing compounds

The annual production of driftwood in Italy has been estimated to be more than 60,000 tonnes. This wood can be used as an energy source. Particular attention should be paid to its content of alkali and alkaline earth metals, sulfur and chlorine. Few works are available in the literature on this topic. For this reason, the authors propose experimental tests of combustion, gasification and pyrolysis, to evaluate the fate of alkali and alkaline earth metals, sulfur and chlorine in the solid residues and compare the three thermal degradation technologies. The results show a release of alkaline earth metals of about 45% of the initial quantity for gasification and a release of 55% of the initial quantity for combustion (while pyrolysis at 600°C has a very low release). The release of sodium is about 65% for gasification and 80% for combustion. It can be seen that the release of sodium is higher than that of alkaline earth metals; this is due to the divalency of the last ones. Dealing with the release of major elements (chlorine, sulfur and AAEMs) the tests have shown that pyrolysis process is a low emitting technology.

Rotary Kiln Slow Pyrolysis for Syngas and Char Production From Biomass and Waste: Part 2 — Introducing Product Yields in the Energy Balance

A micro scale 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 scrubbing section, for tar removal, and to a monitored combustion chamber to evaluate the LHV 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, 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 composition of the yields of the pyrolysis of wood biomass, in terms of syngas, tar and char. Results can be used to choose the correct rotational speed before doing the real pyrolysis test.Copyright