Last updated on: 2012-07-05

Konin CHP Biomass

In March 2010, ZE PAK SA launched the Konin Power Plant Modernization Project. The aim of this project is to prepare the productive base of ZE PAK SA for long-term operation, to make the plant ready to meet future, stricter environmental standards, and to maintain its production potential.


KEY REQUIREMENTS FOR THE PROJECT:

 

  • Upgrades at the Konin Power Plant to be in line with the EU’s strategic guidelines regarding the environmental impact of power plants, laid down in Directives 2001/80/EC (LCP Directive), 2004/8/EC, and others;
  • Electricity to be produced from renewable sources (‘green’ energy from biomass);
  • The process flow at the Konin Power Plant to be simplified;
  • Electricity to be generated taking into account ‘red’ and ‘green’ certificates;
  • The following requirements for emissions of harmful substances into the environment to be met:

nitrogen oxides - 200 mg/Nm³

sulfur oxides - 200 mg/Nm³

dust - 30 mg/Nm³

  • Occupational health and safety and work ergonomics to be improved (lower noise, reduced fire hazard).

A. Construction of a Biomass-Fired Circulating Fluidized Bed Boiler

The most important part of the project is the construction of a boiler plant with a biomass-fired circulating fluidized bed boiler (K9, station no. K12) with a steam output of 215 t/h together with associated buildings and structures that are elements of the process line. The design of the drum-type boiler manufactured by Foster Wheeler Energia Polska sp. z o.o. is based on the circulating fluidized bed concept. Particles are separated in a compact separator and recycled via gill-type sealing back to the bed. The finest fly ash passes through the convection part and is separated from the flue gas in the electrostatic precipitator. The following are the key parameters of the boiler:

Heat output capacity: 154 MWt

Live steam flow: 59.7 kg/s

Live steam temperature: 540 °C

Live steam pressure: 9.7 MPa

Feedwater temperature: 210 °C

Guaranteed efficiency: 91%

Noise not exceeding 85 dB

Total maximum fuel flow rate: 23 kg/s

Primary fuels: forestry biomass, willow chips, straw briquettes, rapeseed oil cake, cherry stones, oat hulls, other alternative fuels

Kindling fuel: light oil

 

PROJECT HISTORY

The history of the project goes back to 30 January 2009, when ZE PAK SA launched a tendering process for the turnkey construction of a biomass-fired circulating fluidized bed boiler at the Konin Power Plant with a steam output of 215 t/h. On 17 March 2009, the Company entered into an agreement with Energoprojekt Katowice SA (EPK) for the preparation of documentation for a project entitled ‘Konin Power Plant Modernization: Construction of a Dedicated Biomass-Only High-Efficiency Fluidized Bed Boiler as a Replacement for the Dismantled Boiler K9 to Power Condensing Turbine TG6 Together with Biomass Management Facilities and Necessary Infrastructure’.

 

On 30 July 2009, ZE PAK SA filed an application to the Municipality of Konin for a decision on the environmental constraints for a project consisting in the construction of a biomass-fired fluidized bed boiler (K9) and ancillary systems and the modernization of turbine generator set TG6. An environmental impact report prepared by EPK was appended to the application.

 

While the process of obtaining official permits and approvals for the project was in progress, on 30 July 2009, ZE PAK SA signed a contract with Foster Wheeler Energia Polska Sp. z o.o. (FW) for the turnkey construction of a biomass-fired circulating fluidized bed boiler at the Konin Power Plant with a steam output of 215 t/h. In August of that year, the parties confirmed that the contract had entered into force.

 

On 29 December 2009, the Municipality of Konin issued Decision No. 20 on the environmental constraints for a project consisting in the construction of a biomass-fired fluidized bed boiler (K9), the modernization of turbine generator set TG6, the modernization of boiler K7, and the modernization of turbine generator set TG4 at the Konin Power Plant, and on 5 February 2010, by Decision No. 31, it approved the building permit design and issued a building permit for the construction of a boiler plant with a biomass-fired circulating fluidized bed boiler with a steam output of 215 t/h together with ancillary buildings and structures being part of the process line at the Konin Power Plant.

 

On 25 February 2010, the owner formally handed over the construction site to Foster Wheeler (FW) for the preparation of site facilities, and on 15 March 2010 FW started civil engineering work relating to foundations for the boiler house and the ancillary buildings and structures. In March, FW began to strengthen the soil for the planned foundations using the deep soil mixing (DSM) technology. The work was done by KELLER Polska Sp. z o.o.

 

On 26 July 2010, FW completed the foundation works for the boiler house and started assembling the main steel structure of the boiler and the boiler plant and the installation of ancillary boiler systems (fuel, sand, ash).

 

In mid-November 2010, the assembly of the steel structure was completed to the point where the assembly of the pressure part of the boiler could begin, and the boiler drum was lifted and suspended on the boiler grate on 22 November 2010. From early December 2010 until the end of April 2011, work continued on the assembly of air and flue systems of the boiler and the installation of 6 kV and 0.4 kV switchgears. Meanwhile, between 10 February and 10 March 2011, a 100-metre-high steel flue stack, 3.2 metres in diameter, was erected.

 

April and May 2011 saw the commencement of the installation of the compressed air, ammonia dosing, fly ash transport and storage, and fire protection systems as well as the electrostatic precipitator with flue ducts connecting the flue stack and boiler. Also, after assembly of the pressure part of the boiler had been completed, a pressure test was successfully carried out under the supervision of inspectors from the Polish Technical Inspection Office (UDT)

 

In mid-August 2011, power was supplied to the 6 kV and 0.4 kV switchgears of the CFB boiler and the start-up of the switchrooms began. On 1 September the installation of wiring and instrumentation of the automatic control and measurement system as well as tests of the master control system for the boiler’s electrical circuitry started.

 

October saw the completion of the boiler brickwork, following which the drying of the boiler setting in the burner area began. After the completion of mechanical assembly work on the various ancillary systems of the boiler, start-up and testing of individual systems began and chemical cleaning of the steam and water systems of the boiler and the main pipelines connecting the boiler with turbine generator set TG6 was carried out. In December 2011, dry maintenance of the pressure part of the boiler was performed.

 

B. Rehabilitation of turbine generator set TG6 and ancillary systems

In connection with the construction of the dedicated biomass-fired CFB boiler and facilities for the storage and transportation of biomass to the 154 MWt boiler that will burn forestry and agricultural biomass, together with the necessary infrastructure, it also became necessary to rehabilitate the turbine hall and adapt the process systems of TG6 to work as a unit with a biomass-fired circulating fluidized bed boiler with a steam output of 215 t/h.

The primary objective of turbine hall rehabilitation was to:

  • extend its useful life for at least another 20 years of operation;
  • make possible the production and sale of ‘green energy’;
  • maintain the rated output at the current level of at least 50 MWe;
  • improve the efficiency characteristics of individual components of the turbine generator set and achieve specific heat consumption below 9300 kJ/kWh (expected value at rated conditions);
  • achieve high operating reliability and high availability, exceeding 97% (turbine and auxiliary systems);
  • improve operating comfort and operating staff safety;
  • maximize economic benefits by optimizing the scope of the modernization and rationally using existing facilities, equipment, and systems in relation to the economic benefits resulting from the achievement of the above objectives (improved capacity, efficiency, flexibility, etc.).

The turbine hall and cooling water system rehabilitation project at the Konin Power Plant covered the following elements:

  • turbine generator set TG6 (LP cylinder; HP-IP part);
  • gland steam system;
  • sealing and drainage system;
  • oil system (control, lubrication, and jacking);
  • generator seal oil system;
  • hydrogen system;
  • condenser (installation of vacuum pumps for extracting water from the condenser water chambers; installation of vacuum pumps for maintaining vacuum in the condenser; installation of a steam inlet to work with a new start-up and dumping station; installation of a continuous cleaning system for condenser tubes);
  • LP heating system with drip pumps (2 × 100%);
  • condenser cooling system;
  • water deaeration station at feedwater tank ZWZ6 (rehabilitation of the feedwater tank and installation of a new deaerator dome with internal fittings);
  • HP heating system;
  • feedwater pump units PWZ8 and PWZ9;
  • generator,
  • turbogenerator pedestal (including replacement of the upper plate);
  • turbine hall electrical wiring and power outlet lead;
  • instrumentation and control systems;
  • renovation and finishing building works;
  • restoring the functionality of Stage II feedwater and live steam headers after the establishment of the K12-TG6 power unit;
  • installation of main pipelines connecting boiler K12 with turbineTG6 and existing Stage II ancillary manifold systems.

Key requirements for the upgraded turbine hall and turbine generator set TG6:

  • low consumption of water, steam, and incoming energy to ensure low operating costs;
  • optimized, low level of capital expenditure on the upgrades (while meeting technical requirements of modernization) through the rational use of existing facilities and installations;
  • availability as indicated above and optimized low turboset maintenance costs related to the planned repair cycle:

–          major overhauls             up to 50 days, every 6 years,

–          medium-term repairs      up to 25 days, every 2 years (excluding major overhaul years),

–          running repairs              up to 8 days in each year;

  • compliance with applicable standards and regulations relating to the safety of the technology and the impact of the technology on the environment and on staff working conditions;
  • fulfilment of turbine generator set flexibility requirements;
  • use of available useful facilities of the existing turbine hall (existing building, reconstructed foundations, part of the equipment, infrastructure, etc.);
  • meeting the applicable standards relating to thermal, sound absorption, and corrosion protections, paint coatings, etc.;
  • the upgraded turbine generator set to have adequate thermal and acoustic insulation to meet occupational health and safety standards; reusable insulation with sound-absorbing elements required.

 

C. Construction of biomass storage and transportation facilities for the 154 MWt biomass-fired CFB boiler together with the necessary infrastructure and modernization of underground systems at the power plant site

Under rated operation conditions, biomass consumption of the power unit fired with forestry and agricultural biomass is about 65 t/h and depends on the instantaneous heating value of the fuel. To ensure stable operation of the boiler, it is critical to maintain consistent fuel quality, avoiding big changes in fuel characteristics (e.g. its calorific value).

 

Fuel quality should in all cases and at all times be maintained in accordance with specifications provided by the manufacturer of the boiler, so as to avoid disruptions of operation, plant damage, excessive corrosion, erosion, unavailability, etc. The primary fuel for the boiler consists of biomass in the following forms:

  • forestry wood chips (shredded/chipped wood in the form of fibres, chips, or shavings about 5 to 50 mm in length). The moisture content of wood chips depends on their origin. The moisture content of those produced from green parts of trees is approximately 50–60% of total mass;    
  • wood chips from willow crops (willow chips are not significantly different from other types of wood chips but may contain more bark and moisture). Particular note must be taken of the increased content of alkali metals (mainly sodium and potassium) in this fuel. The calorific value of dried willow is no different from other species and is about 18 GJ per tonne of dried material. However, compared to most other species, willow wood is relatively light.

Eighty per cent of the biomass fuel will be obtained from forestry and twenty per cent from farming, agricultural produce processing industries, and from so-called ‘energy crops’, all of which will be referred to as agricultural, or agro, biomass.

 

Generally fuel prepared for use in the boiler should be free of unfluidizable material (rocks, ice, metal, glass, etc.). In no case should the content of unfluidizable material in the fuel exceed 0.1 per cent of dry mass. All unfluidizable material must be able to pass through a 50 mm sieve and the total of all dimensions (L+ W + H) must not exceed 100 mm.

 

Thus, a key, or indeed the main, purpose of a biomass logistics system is to supply the CFB boiler with fuel in the form of a precisely formulated biomass mixture in such a way as to ensure continuous, uninterrupted operation. The system should include, among others, the following elements:

  • Automated reception of biomass from transport vehicles;
  • Storage of about 47,000 m3 of biomass;
  • Capability to simultaneously store several types of agricultural and forestry biomass in the form of wood chips, sawdust and bark in the required proportions;
  • Transportation of the biomass mixture to boiler bunkers in required proportions of the different biomass types;
  • Ensuring the required performance (throughput) and availability of the installation.

Another essential condition to be met by the biomass transportation facility is compliance with requirements specified in the Regulation of the Minister of Economy of 14 August 2008 on detailed scope of obligations with respect to obtaining certificates of origin and submitting them for cancellation, payment of a substitution fee, purchase of electricity and heat from renewable energy sources, as well as the obligation to confirm data on the amount of electricity produced from a renewable energy source (Dziennik Ustaw 2008, No. 156, Item 969), known as the RES Regulation.

 

The biomass storage and transport facility serving the CFB boiler has a transparent and credible system for guaranteeing the origin of electricity produced from renewable energy sources, according to the principal criteria, which include the following:

  • correct qualification of biomass for combustion;
  • ensured required accuracy of physical measurements that are inputs to the calculation formula, in accordance with the requirements specified in the Measures Act;
  • simultaneity of mass measurement and collection of samples of biomass fed to the combustion process in the power boiler for unambiguous determination of the chemical energy flux introduced with the biomass fuel;
  • a location for the measurement of the mass of agricultural biomass or biomass from energy crops ensuring reliable determination of the participation of such biomass in the total biomass stream fed to the combustion process;
  • uniformity and reliability of testing procedures used to determine the physicochemical properties of biomass;
  • comparability of the competences of the laboratory that will test the physicochemical properties of fuels burnt;
  • proper source documentation flow and archiving.

As can be seen, the biomass storage and transportation facility must meet strict requirements of the Polish Energy Regulatory Office, criteria for the physicochemical characteristics of the biomass and for the biomass-combustion unit, i.e. the boiler.  The biomass storage and transport facility for the 154 MWt biomass-fired CFB boiler together with the necessary infrastructure meeting such requirements has been built at the Konin Power Plant.

 

D. Construction of Ekoterm light kindling oil handling facilities

The new CFB boiler equipped with pressure-type burners will use Ekoterm oil as kindling fuel, which made it necessary to build new kindling oil handling facilities with suitable systems and equipment. The oil handling facilities are located in the south-eastern part of the Konin Power Plant site.

The facilities consist of a terminal for unloading oil from rail tank cars and road tankers, oil storage tanks with a capacity of 500 m3, a kindling oil pumping station with transport pipelines to the boilers, and an oily wastewater treatment plant.

 

On 10 May 2012 a new power unit was synchronized with the National Power System. Also in May, the adjustment run was carried out, after which the 720-hour trial run of the whole power unit started. On 29 June 2012 the power unit was ceremonially handed over to the investor and once the trial run was completed the full commercial operation of the power unit began.

 

The rated power of the new power unit in Konin Power Plant is 55 MWe. Under rated conditions the boiler can incinerate approximately 65 tons of biomass per hour. 80% of the biomass will be forest biomass and 20% - agricultural biomass. The power unit guaranteed efficiency is 91%. Apart from high operational reliability and high availability factors at the level of more than 97% (turbine with auxiliary systems), the new power unit provides a high level of safety for employees and comfortable operation.

 

The commissioning works for the new power unit were initiated at the beginning of 2012. On 10 May 2012 the power unit was synchronized with the National Power System. Also in May, the adjustment run was carried out, after which the 720-hour trial run of the whole power unit started. On 29 June 2012 the power unit was ceremonially handed over to the investor and once the trial run was completed the full commercial operation of the power unit began.

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  • ZE PAK SA
    Company’s Head Office
    ul. Kazimierska 45 | 62-510 Konin
  • tel. +48 63 247 30 00 fax. +48 63 247 30 30 zepak@zepak.com.pl
  • ZE PAK SA Place of registration: Sąd Rejonowy Poznań Nowe Miasto i Wilda IX Wydział Gospodarczy.
    KRS 0000021374 | REGON 310186795 | NIP 665-000-16-45
    Share capital: 101 647 094 PLN, fully paid-up.
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