Plants_no_10.pdf

Cofiring of biomass - evaluation of fuel procurement and handling in selected existing plants and exchange of information (COFIRING) - Part 2 Virginia Bombelli, KOBA l CIPRO l Plant 10 1. General information of the plant
1.1 Enterprise
ENEA is the Italian Agency for New Technology, Environment and Energy.
At the Research Centre located in Saluggia, the activities of the “EnvironmentalFriendly Energy Systems” Unit are dealing with: • Diffusion of renewable energy, as biomass and waste combustion• Combustion research of non conventional fuels• Emission and Efficiency control and monitoring• Boiler and burner test facility• Demonstrative plant 1.2 Plant
biomass, agro-industrial (non hazardous) residues, driedsludge from sewage treatment plants.
2.3 t/h (at lower heating value of 3300 kcal/kg - Biomass and waste unloading: square yard on ground level Biomass and waste storage capacity: 100 m3 1.3 Purpose of the plant
Demonstrative and experimental plant, with test facility for heat generator appliancestesting in the range of 0,3 to 3,0 MWth.
Virginia Bombelli, KOBA l CIPRO l Plant 10 1.4 Milestones of the project
1993-1995
1996-1998
Agro-industry residues combustion tests: pure and mix 1999-2000
New plant realisation, authorising wastes combustion tests 1.5 Reasons for cofiring of biomass with other fuels
Depending on the heating period and requests, the bio-fuel availability during the year is highly seasonal and logistics dependant (e.g. geographical position of the plantrespect to the biomass production area). For this reason the use of non pure solidbiomass fuels, as mixed with residuals or non hazardous wastes, in the solid fuels burner, or in substitution with oil burner, is the only way to allow the survival ofbiomass plants. This solution can be done to solve land-fill deposition of solid residuals,without real re-cyclable re-use in a convenient way, as long distance transportation or quantity and quality of the residuals, to allow a local combustion application to avoidoil/natural gas consumption, CO2 un-wanted emissions, and land-fields deposition.
The typical application is the district heating system for small communities andindustrial applications as heating plants, where the biomass combustion helps also therural areas, as forest and field manuring.
1.6 Manufacturers of multifuel biomass boiler, solid fuel
handling equipment and control system suppliers
ETG – Italy (FTIR Cermet Finland,NDIR Mayak Germany, FID NIRA Italy, etc.) Virginia Bombelli, KOBA l CIPRO l Plant 10 1.7 Other information
Connections to the local energy production and distribution (power/heat consumers):No ones Calorimetric circuit to measure efficiency Wood chips as a reference fuel in the range of the lower heating value from 6280 to 13816 kJ/kg (1500 - 3300kcal/kg) 2. Process description
2.1 Combustion lines
feeding and movement of waste and regulation of primary and secondary air: through a fullyautomatic "expert system", guided by infra-redcameras >1100 °C (referring to >950 °C for over 2 secs) 2.2 Gas cleaning system
Virginia Bombelli, KOBA l CIPRO l Plant 10 2.3 Energy recovery section
Not present, only a calorimetric circuit to measure useful hot water and to compareefficiency measured by direct and indirect methods.
2.4 Energy recovery net efficiency
• low combustion air excess (6% O2), prescribed by authorising environmental • simplicity of the process avoiding unnecessary treatments and transports of the agro-industry materials to the landfields • equipped with a high efficiency on cleaning flue gas (for this nominal heat output Due to the fact the burner is not integrated into the boiler, the resulting net efficiency islower than 80%, depending on fuels characteristics Virginia Bombelli, KOBA l CIPRO l Plant 10 3. Fuels and fuel procurement
Solid biomass fuels: wood, wood residues, logging residues, bark, sawdust, straw, riceask, cocoa beans ask, hazel nuts ask, fruit stones, (Moisture content = 45-55%, lowerheating value = 8-10 MJ/kg).
Support and start up fuel: oil (diesel oil) Biomass fuel procurement systems: the biomass will be bought directly by farmers,saw-mills, food industry.
Biomass fuel pricing: (it is strongly depend locally) it is based on commercial qualitywood chips (LHV higher than 16 MJ/kg) and the price may be between 20 –25 EUR/tdepending on water content. The other materials, considered like waste, have not a market price, but only an avoided disposal price for the producer, which is for smalldelivery only a transportation cost.
4. Fuel handling and feeding system
4.1 Fuel receiving
Fuel receiving at the open-air square yard. Storage under roof in pile for solid fuels ;receiving and storage in big-bag for sludge and small size waste.
Delivery control and management: delivery depending on test activity, mixing withmixing machine, visual control, sampling and analysis in the laboratory existing at theplant.
4.2 Problems in receiving
Particle sizing and crushing (Bulk materials must be crushed) Crushing machine available for reduction in size.
In project, evaluation of briquetting process.
Virginia Bombelli, KOBA l CIPRO l Plant 10 4.3 Storage
Type of storage: under roof in pile, or big bag.
Capacity: 100 m3 total and effective volume.
Fire safety control systems approved by the command of fire brigade of Vercelli 4.4 Boiler feeding
By lift track using 200 l petrol tank to serve a feeding hopper by means of a belt and ascrew conveyors. The belt conveyor is controlled by motor gear regulator and weightingscale.
5. Ash handling
Due the un-continuous operation of this plant, all the residues and dust removal fromburner, boiler and filters are done manually, and these residual materials (equal to about20% of mass of the waste treated), are usually deposed in authorised landfills, without aspecific inertization process.
6. Control and cleaning
All the parameters are under control by data acquisition and the gas emission measureare done before and after the flue gas cleaner.
The measured flue gas components are: O2, CO, CO2, TOC as CH4, SOx, NOx, H2O,HF, HCl and dust as particulate matter.
6.1 Operations reliability and safety:
• Implementation of well proven technologies: e.g. direct combustion on grate, dry • good level of monitoring of the plant Virginia Bombelli, KOBA l CIPRO l Plant 10 6.2 Environment protection
The following solutions have been adopted: • combustion system for minimisation unburned • dry gas cleaning system using sodium carbonate to reduce the micro pollutants • continuous monitoring system of the emissions by using advanced type analysers • very low water consumption with no liquid effluents 7. Investment and maintenance (costs)
1 MEUR (+building cost more then 0.5 MEUR) 8. Remarks and conclusions
The efficiency of energy production is an important environmental protection factor, as it allows both the saving of non-renewable energy resources and the avoidance ofemissions from plants fired with traditional fossil fuels.

Source: http://www.afbnet.vtt.fi/r10.pdf