David Chiaramonti

Development of emulsions from biomass pyrolysis liquid and diesel and their use in engines—Part 1 : emulsion production

The current method of utilising biomass derived fast liquid (bio-crude oil or bio-oil) in a diesel engine requires three fuels and a complex start-up and shut down procedure. For more rapid and successful commercialisation of this renewable liquid fuel, a more convenient and cheaper method of utilisation is needed that provides a single fuel that is stable and readily ignites in a compression engine. This paper describes the production of emulsions from biomass fast pyrolysis liquid and diesel fuel for utilisation in diesel engines. The objective is to allow unmodified diesel engines to run on fast pyrolysis liquid derived from biomass without the cost and complexity of a dual fuel system. The immediate application is in stationary engines for power generation, but there are longer term opportunities for use as a transport fuel. This paper describes the production of the emulsions that have been tested in different diesel engines (tests in engines is reported in a separate paper).

Development of emulsions from biomass pyrolysis liquid and diesel and their use in engines—Part 2: tests in diesel engines

Abstract The use of biomass derived pyrolysis oils, bio crude oil (BCO), in diesel engine requires deep modifications to the engine, such as the adoption of dual fuel systems and pilot injection: BCO/diesel emulsions are expected to significantly reduce the need for these adaptations. This paper describe the effects of various BCO/diesel emulsions on the injection systems of different diesel engines. Materials used for injectors’ nozzles and needles are investigated and compared. The issue of the erosion and/or corrosion of the injector nozzle is examined, and dedicated tests have been carried out. The experimental results suggested that corrosion accelerated by the high velocity turbulent flow in the spray channels is the dominant factor. A stainless steel nozzle has been built and successfully tested. Long term validation is however still needed.

Oil production by the marine microalgae Nannochloropsis sp. F&M-M24 and Tetraselmis suecica F&M-M33.

Nannochloropsis sp. F&M-M24 and Tetraselmis suecica F&M-M33 were cultivated outdoors in Green Wall Panels under nutrient deficiency to stimulate oil synthesis. Under nitrogen deprivation, Nannochloropsis attained average biomass and lipid productivities of 9.9 and 6.5 g m(-2) day(-1), respectively. Starved Tetraselmis cultures achieved a biomass productivity of about 7.6 g m(-2) day(-1) and a lipid productivity of 1.7 g m(-2) day(-1). Lipids represented 39.1% and 68.5% of non-starved and starved Nannochloropsis biomass, respectively. Starvation did not increase lipid content in Tetraselmis biomass. Important differences in lipid classes and in fatty acid composition were observed under the different cultivation conditions for both microalgae.

Submarine seawater reverse osmosis desalination system

The project presented addresses the strategic topic of providing drinking and irrigation water through seawater desalination via a very energy-efficient and cost-competitive submarine technology. In conventional surface based industrial desalination plants applying the reverse osmosis (RO) technology, the freshwater flow behind the membranes is approximately 20–45% of the inlet seawater flow, depending on membrane type and characteristics. The resulting brine is disposed off into the sea. While state-of-the-art RO installations generate the required pressure with seawater resistant high-pressure pumps, the innovative submarine approach uses seawater hydrostatic pressure. The desalinated water, produced at about atmospheric pressure and collected in a submarine tank at the same working depth, is pumped to the sea surface. This approach saves about 50% of the electricity consumption with respect to an efficient conventional RO plant (about 2–2.5 kWh/m3) since only the outlet desalinated water is pumped instead of the inlet seawater, thus reducing the pumping flow rate by 55–80%. It avoids the pretreatment of the inlet seawater, therefore saving costs for chemicals and equipment.

Energy crops and bioenergy for rescuing deserting coastal area by desalination: feasibility study

Abstract The proposed innovative approach identifies a new application for biomass. Bioenergy is used to drive a desalination unit which produces water for irrigating energy crops. Biomass is cultivated on artificial soil made by a mixture of local soil and organic compost from MSW (Municipal Solid Wastes). This agro-energy farm scheme aims at rescuing arid lands near to the sea. The study defines a techno-economic compromise among energy crops, biomass generator, desalination unit and irrigation system, considering an arid area (10 ha) of Tenerife as reference case study. A small experimental activity (100 m 2 ) has also been performed on site. A Sweet Sorghum cultivation, a bioenergy generator, a reverse osmosis plant and drip irrigation system have been chosen. The main result of the study is that the possibility of retaining some 14–20% surplus (in terms of biomass or energy or water) exists. The system is energetically feasible: rescued land can be doubled in approximately 4 yr. This approach is applicable to many Mediterranean coastal areas, as well as other similar situations elsewhere.

Evaluation of a Micro Gas Turbine Fed by Blends of Biomass Producer Gas and Natural Gas

Small scale gasification is a promising technology for bioenergy generation. Reciprocating engines are usually combined with downdraft gasifiers, nevertheless this approach is associated with high emissions, in particular CO and NOx and with a limited co-generation potential. MGT technology, rapidly improved during the last years, offers the possibility to reduce the levels of pollutants in the exhaust. Moreover they offer some other advantages in the small size range, such as a higher exhaust gas flow at higher temperatures, while maintaining a similar net electric efficiency. Evaluating the possibility to couple a MGT with a gasifier, the quality of the producer gas is also a relevant issue. In this work an overview of the typical gas quality produced by existing small scale gasifiers is carried out; moreover, a review regarding the syngas combustion in GT is realized, considering GT requirements related to gas composition. Co-firing with natural gas is considered, in order to reduce the modification needed to the engine. An evaluation of the proper range of mixing is then carried out. The performances of a commercial 100 kWel MGT are then simulated by means of an “in-house” developed code named AMOS (Advanced MGT system Operation Simulator). This tool allows to perform a steady-state matching analysis based on the characteristic lines of each component, when using a low calorific gas in a MGT. Producer gas and natural gas mixtures are considered and a parametric study is carried out. Performances were computed considering MGT full-load operation.Copyright

Process Analysis and Modelling for 2nd Generation Lignocellulosic Bioethanol Production

In the present work, the most promising processing technologies for next generation ethanol production are assessed. A literature-based comparative analysis of the technologies in terms of yield, efficiency, feedstock and level of process integration is carried out in order to identify the most interesting ones. The aim of this paper is the analysis and validation based on literature data of a process simulation performed using the software Aspen Plus. The model is intended to understand the major process steps and focuses on the main aspects from an energy engineering point of view. Moreover it provides an useful tool for preliminary analysis of different configurations. Crucial aspects include high pretreatment yield, efficient hexose and pentose fermentation, enzyme strain development and solid residue valorization for process heat and power generation. Energy and mass balances are modeled, so to allow a comparison among different technological solutions. A plant able to process 240,000 kt/y of biomass is modeled, showing a production capacity of about 40,000 kt/y of ethanol. Ethanol productivity is over 300 L/t of dry biomass, and net process energy efficiency is calculated over 35%. The model developed focuses on the main steps of the production process allowing for further development or process optimization.

Preliminary Design and Economic Analysis of a Biomass Fed Micro-Gas Turbine Plant for Decentralised Energy Generation in Tuscany

Biomass is a significant renewable energy source in Tuscany. A GIS-based software model, jointly developed by the Energetics Department of the University of Florence (DEF), the Agriculture and Forestry Economic Department of the University of Florence (DEEAF) and Energia Trasporti Agricoltura (ETA) in the framework of a LIFE supported project (BIOSIT) has been used to estimate the available resources in the Tuscany region. In this context, a gas turbine cycle based on a dual combustion system has been considered (DCGT, Dual Combustion Gas Turbine). The size of the plant (∼100 kWe) targets small decentralised power generation. The DCGT system aims at achieving a great flexibility through both internal and external firing. In fact, the adoption of an external combustion chamber makes possible to adapt the plant to various types of solid biomass without affecting significantly the thermodynamic cycle and therefore the performances. The technical analysis of available industrial components (gas turbine, heat exchanger, biomass combustor) has been carried out. The computation of the thermodynamic performances was carried out by a dedicate in-house developed software. The economic analysis was performed for the proposed system, and a sensitivity analysis on the critical parameters elaborated. The use of natural gas and bioethanol was also compared in the dual combustion mode.Copyright

Deployment of a submarine reverse osmosis desalination prototype plant (RODSS): field tests and preliminary technical evaluations

Abstract The innovative RODSS approach (Reverse Osmosis Deep Sea System — EU-DG XIII innovation project 1998–2001) exploits seawater hydrostatic pressure at a depth of about 450m below sea level. This presentation concerns the deployment and field tests of a small-production-capacity (10m 3 /d) prototype desalination unit immersed 1 mile offshore the southwest coast of Pantelleria Island, Sicily. The desalinated water produced in the sea depth at about atmospheric pressure is continuously pumped up through a buoyancy controlled reinforced conduit to a storage tank ashore via a high-pressure pump sited in the sea depth. The RODSS prototype has required a dedicated design work for all its components: it consists of a 5m long fiber glass pressure vessel, which contains all working apparatuses (osmotic modules, desalinated water storage tank, sea water circulation pump, desalinated water delivery pump, flow meters, temperature and pressure transducers, etc.) and a sea-line (desalinated water delivery conduit and electric power cable joined together) connecting it to the plant site ashore. The deployment of the RODSS prototype is described with the help of short texts and field pictures. The field tests of the RODSS prototype concern its working characteristics and are presented with the help of dedicated tables which detail the numerical values of basic parameters such as: working pressure, water salinity and temperature, and conversion coefficient. The presentation ends with preliminary conclusions on the RODSS technology potential for seawater desalination vis-a-vis conventional RO technology.

DESERESCUE: Small agro energy farm scheme implementation for rescuing deserting land in small Mediterranean islands, coastal areas, having water and agricultural land constraints. Feasibility study

ABSTRACT Deserted zones in the Mediterranean area are a serious problem, in particular if it is considered that this phenomenon is continuously growing year after year. The feasibility study of a small scale project enclosing a pilot cultivation of energy crops, totally self-sufficient in terms of water (RO/Distillation system for sea water desalination) and energy supply capability (generator set stoked up by biomass), constitues an essential element for the reconstruction of an artificial good quality soil. In fact, this system could demonstrate its capability of arresting the desertification process. Great importance has to be given to the study and the improvement of crop characteristics (in relation to soil composition, crop and irrigation system, etc.) because of their influence on energy/water production.