At PowerGen - RENEWABLE ENERGY WORLD Europe - June 2013: Multi-fuel Fired Biomass Cogeneration Plant by

Transcription

1 At PowerGen - RENEWABLE ENERGY WORLD Europe - June 2013: Multi-fuel Fired Biomass Cogeneration Plant by FSL/ Andrea Bigai, Technical Manager, Zignago Power Frank Scholdann Lund, Area Sales Manager, Aalborg Energie Technik a/s Slide 1: Introduction This is a joint presentation between Zignago Power and Aalborg Energie Technik represented by Andrea Bigai and Frank Scholdann Lund. This presentation relates to a multi-fuel biomass fired cogeneration plant, which is developed, built and operated by Zignago Power in Fossalta di Portogruaro, north of Venice (Region Veneto), Italy. The CHP plant, in which the heart is the multi-fuel fired 49,2 MWt boiler, will supply up to 4.5 MWt district heating to nearby cities and 17,2 MW of electricity to the local grid. In the target of getting lower CO 2 levels, Italy were promoting biomass fired plants, but due to the different legislations over the last 10 years, only few plants have been realised and even fewer has been in operation with great success. The construction of the CHP plant for Zignago Power began in November 2009 and commercial operation by November In the aim of suppression the overall carbon foot print great efforts has been undertaken to optimise the fuel logistic. One of the main goals was to design a plant being able to operate based on the available fuel within a radius of 70 km from the plant. The multi-fuel boiler is able to burn agricultural waste like maize, straw, wine residue, straw and wood. This created several challenges for the boiler design as straw and maize have high corrosive Page 1 of 9

2 characteristics; wine residues create fouling in the furnace and/or in the heating surface and have extreme high ash content. Another challenge were, with this high fuel flexibility, to full fill the stringent emissions, like CO < 50 mg/nm 3, and at the same time have a low NOx level (< 180 mg/nm 3 ). The chosen combustion technology is Best Availability Technology with high boiler efficiency (> 92%), even with high fuel moisture content. All-in-al the plant has now after almost 1 year in operation proven its low operational costs and at a high availability. Slide 02: Zignago Group and Zignago Power Zignago Holding consists of Zignago Vetro (manufacturing of bottles), Santa Margherita (wine production), Zignago Power (renewable energy), finance group. Main figures for 2012 for Zignago Group: No. of companies: 30 No. of employees: 2110 Turn-over: 410 meur The green energy production : 2 biomass fired plant (The biggest in Fossalta di Portogruaro) m2 of photovoltaic Main figures for 2012 for Zignago Power in Fossalta di Portogruaro: No. of employees: 35 Power produced: 121 GWh Slide 03: Italy & Biomass Zignago Power - Fossalta di Portogruaro ( ): Apply for power certificate: power price. Apply for building permit Apply for environmental permit Professionals against combustion of biomass Only few biomass fired plants realised in Italy the last 5 years. Page 2 of 9

3 Today ( Decreto Rinnovabili from 6 July 2012): > 5 MWe: Apply for building permit, environmental permit Apply for power certificate in auction Auction FEB 2013: 1 plant (13 MWe) applied for a Cap of 120 MWe Not attractive scheme 0,2 5 MWe: Apply for power certificate; once per year JAN 2013: 239 plants (221 MWe) applied for a Cap of 170 MWe Slide 04: Motivation for Zignago Glass factory have constant power consumption Biomass: constant power production. No power distribution costs (20 EUR/MWh) 2008/2009: Decision - Improve competition. Slide 05: Transparent & open-minded approach Zignago is working in an open-minded approach with all involved: Suppliers Authorities Local community. Signed an agreement with local community (MAY 2009) Only clean biomass fuel Local authorities have continuously check Control group elected by the community (5 people) can check the plant and performance, when they want Local extra work: Greening/plantation around the plant Parking area for cars Page 3 of 9

4 Road upgrade AND new access road to site Environmental emission studies (first plant in Italy) - ARPAV: Before operation of the plant: Air quality, emissions from plant, biological statement After putting plant into operation: Emissions from plant (dust, NOx, CO, dioxin, furan, PCB, PM 2,5/10 ), Air quality (compare with earlier), Biological statement Slide 06: Fuel strategy clean multi-fuel Agreed back in 2008/ 2009 with the local communities the basis for the biomass fired plant shall be clean fuel. To keep the longterm fuel costs down we decided to go for a multi-fueled boiler: AGRICULTURAL SECTOR Residual: Maize, staw, grains Fruit trees, wine yard residue Decicated culture: Sorgum, miscanthus, arundo, bamboo, hemp Short rotation crop; poplar FORESTRY SECTOR Chipped / unchipped wood Maintenance of green areas We try to use the local fuel low transport costs in order to keep the fuel costs down. Slide 07: Flow Scheme This flow scheme represents: the arrival of the biomass to the boiler the production of steam by the boiler to the turbine the air cooled condenser the delivery of steam to the customer site the steam production on the customer site through a steam generator. The steam generator isolates the circuits of the cogeneration plant from the circuits of the customer who needs a steam of food quality the return of condensates FSL/ Page 4 of 9

5 Slide 08: Plant Layout The site has a surface of 5 hectares, half of which is dedicated to the storage of biomass fuel outdoor. Two other covered areas are dedicated to the storage of biomass, one of them being fully automatic to supply the boiler. The boiler is the highest building of the plant: 20 m. Slide 09: Plant Key Data Boiler capacity: 49,2 MW; steam: 62 t/h, 522 C & 92 bar Biomass consumption: t/year; trucks / day Capacities of STG / WCC / DH: 17,9 MWe / 28 MW / 4,5 MW (peak) Global efficiency: 35 % / 44 % Budget: 55 M Number of direct suppliers: 18 only 11 present at site Duration of the project: 33 months Hours worked of site: h (50% boiler, 27% STG) Number of companies on site: > 100 companies, 6 non Italian Safety introduction: > 1000 people went through safety introduction Peak presence on site: 160 people (November 2010) Accidents: 0 lost-time acc., 1 acc. without lost time Record «0 accident»: 334 days & h worked without accident Near miss accidents: 10 during commissioning Production team: persons Duration of commercial contracts: 20 years Slide 10: General planning Authorisation to erect/manage plant: FEB 2009 Scouting of suppliers: MAR 2009 MAY 2010 Contract signature for boiler: NOV 2009 Page 5 of 9

6 Contract signature for STG: DEC 2009 Starting of civil works: APR 2010 Starting of mechanical erection: JUL 2010 Cold commissioning: JUN 2011 Hot commissioning (first fire): SEP 2011 Power on grid: NOV 2011 Deadline for environmental fulfilment: APR 2012 Provisional acceptance of boiler: MAY 2012 Provisional acceptance of STG / WCT: OCT 2012 Performance test: APR 2013 Slide 12: Aalborg Energie Technik (AET) AET is an engineering and contracting company, which is focused on designing, managing, supplying, erecting, commissioning and servicing biomass fired boiler plants or turnkey plants. This is with boilers in the range of MW. AET have made projects in UK (turnkey for clean wood, chicken litter, meat & bone meal), Scotland (wood and distillery grain fired plant), many waste wood fired plants in Germany, clean and waste wood fired plants in Austria, plant in Italy with wood, wine residue sorghum, maize etc., coal to wood conversion in Denmark and now two projects for Cofely in France. AET can supply the boiler, flue gas cleaning system or even the full turnkey for biomass fired plants or in a consortium, like on WWEP. Since the foundation in 1996, AET has had a stable growth and employs about 100 people today and has had well financial ratings and technical plants selected as "Best Available Technology". AET cover Europe as market with focus on selected countries with special development. Financially AET is very strong and has a good foundation since the employees own approximately 40 % of the shares in the company. Slide 13: Fuel and their characteristics As shown by Andrea the fuels are many and different fuel has different challenges. Page 6 of 9

7 The forestry wood: The advantage is that it is very easy accessible all the year around and easy to make long term contracts. On the other hand it is often Very wet (55 % moisture) or in summer time down to 35 % moisture creating challenges with CO emissions Dry (35 % moisture) balancing this mainly with higher combustion temperature and creating thermal NOx. The brash bales have very high ash content creating fouling and high ash amount in the boiler. The agricultural sector residuals: The advantage is that it is often very cheap as seen as waste and for no value, although it is seasonable. The straw is most often with high chlorine content, potentially creating high temperature corrosion and very high alkali content, potentially creating fouling The agricultural sector dedicated: The advantage is that it is often relatively cheap as it can be grown as a supplement to existing farming. This type of fuel is typical the same challenges as for the residuals from agriculture. Slide 14: Fuel flexibility and impact on design To handle this wide fuel band some extra ordinary has been made on the fuel dosing, boiler and flue gas treatment. Just quickly the concept: fuel dosing bin, spreaders, travelling grate, combustion zone, post combustion zone, superheater tube banks, economiser and bag filter. The dosing bin, rotary valves and spreaders insure that there is a uniform and well distributed fuel injection in to the furnace. Primary air is injected through the travelling grate and the secondary air is injected through several nozzle levels on both the front wall as well as the rear wall. Page 7 of 9

8 Approximately, 50% of the fuel burns in the suspension and the rest is being burnt on the grate as it transports travels towards the furnace front wall. The combustion conditions like sufficient combustion temperature and combustion air flow is controlled via the control system and by use of only very limited amount of refractory. This minimises the start-up and shut-down time to a few hours and the maintenance costs are minimised as well. The furnace is designed at minimum 2 seconds of residence time above 850 C to ensure a full and stable combustion. The flue gas passes through a SH 3 turn upwards through a new superheater bank and turns into the economiser tube banks. The final superheater is positioned in 2 nd pass (out of direct radiation) and at approx. 850 C in order to minimise high temperature corrosion and fouling. The heating surfaces are designed with low flue gas velocity and with horisontal tubes and buildup of slag is practically none existing either in SH and ECO. Due to the low oxygen content, good combustion and low soot formation the performance is very high and creating a very stable steam flow. The soot blowing is typically being performed once per day or each second day depending of the fuel is clean wood or more dirty wood. To ensure a very high combustion efficiency carbon ash re-injection is added. All these systems here are designed internally in AET in order to To minimise the dust level a bag filter is installed. The boiler plant is operating with very low power consumption as there is low oxygen air content and resistance is low - only controlled, but low pressure drop over the grate and bag filter. Slide 15: Emissions The emissions here are verified data from April this year and showing that the emissions are well within the guaranteed values. These are all a result of the excellent combustion. Just to mention of few of these: Dust: <0,5 mg/nm3 NOx: approx. 160 mg/nm3 CO: approx mg/nm3 SO2: nearly not detectable. Page 8 of 9

9 These were the guaranteed values. AET have further more measured (which are compared to EU limits): HCL: nearly not detectable and e.g. Dioxin/Furan: are nearly not detectable. Performance wise: The combustion efficiency is better than 99,9% The boiler efficiency is 92,6% Power consumption for boiler only: 585 kw. The AET Combustion System is with these low emission levels recognised at Best Available Technology. Slide 16: Zignago Conclusion Overall efficiency: 35 % / 44 %. Low in-house power consumption: App. 2 % of fuel heat input. Very reliable plant: 94 % availability with operating team of 14 persons Low emissions: Limited use of SNCR denox Successful commercial operation: Active since NOV 2011 Successful partnerships with suppliers Successful partnership with local authorities Safe Construction & Operation: 0 lost time accident On-going improvement: District heating Opportunities to improve: Availability and development of DH needs Page 9 of 9