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Forlì waste-to-energy plant

Via Grigioni 19, Forlì, Coriano district

  • 1 / 6   Forlì waste-to-energy plant
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  • 6 / 6   Forlì waste-to-energy plant

The plant is located at Via Grigioni 19 in Forlì, Coriano district, and consists of a single incineration line, line 3, which began operating in August 2008. The phasing out and demolition of the two old lines, 1 and 2, finished in October 2009.

The installation of line 3 resulted in an upgrade in the plant´s incineration potential, from 60,000 to 120,000 metric tonnes per year, as set forth in the provincial waste management programme.

The Forlì plant complex also includes two other activities, a mechanical waste pre-selection plant, which processes at least 70,000 metric tonnes of non-hazardous waste per year, and an ecological platform.

Page updated 26 August 2015

    Number of waste-to-energy lines
    Total thermal capacity
    Approximately 46.5 MWt
    Combustion technology
    Water-cooled moving grate incinerators
    Waste disposal capacity
    Max. 384 tonnes/d with LCV of 10,465 kJ/kg
    Annual operation
    7,500 hours
    Rated electric power
    10.6 MWe
    Disposal and recovery codes
    D10; D13; D15
    Type of waste accepted
    Municipal waste; special waste (dry non-reusable fractions) coming from the adjacent waste pre-selection plant

    Environmental compatibility with current regulations (Legislative Decree 152/06)

    The waste-to-energy plant makes it possible to dispose of a variety of waste through combustion. The heat this generates is exploited to produce heat and electricity.

    1 - Waste receipt and storage.
    The plant has two waste storage pits. An auxiliary storage pit, used to receive the waste to be sent for pre-selection and to carry out transfer operations if the new waste-to-energy plant is shut down, and the main pit, serving line 3, equipped with a roof over the area where the transport vehicles unload and manoeuvre (foredeep). The waste to be sent to the waste-to-energy plant can be delivered to the main storage pit or to the auxiliary pit to feed the pre-selection plant. The main waste pit is underground and is located inside a closed building. It is completely made of reinforced concrete and has a waste storage potential of approximately 4,000 m 3. The waste is moved inside the pit by two bridge cranes equipped with polyp-grabs, which load the hopper that feeds the incinerator.

    2 - Combustion.
    The plant is equipped with a water-cooled moving grate incinerator, which is able to incinerate up to 16 metric tonnes of waste per hour with a lower calorific value of 2,500 kcal/kg. The alternating movement of the rungs of the moving grate ensures that while the waste progresses to the combustion chamber, it is mixed to facilitate combustion and decrease the amount of uncombusted materials in the remaining slag. The air needed for the incineration process enters the combustion chamber through the grate (primary air) and through the openings located on the side walls (secondary air). The primary air is suctioned from within the waste storage pit in order to keep the pit in a vacuum, thereby preventing the spread of odours to the outside air. In addition, to increase energy efficiency, before the primary air enters the combustion chamber it is pre-heated through heat exchangers which use the steam generated by the boiler. To ensure that combustion is complete, the residues are then conveyed to the post-combustion chamber, the size of which ensures that fumes remain at a temperature above 850°C for at least two seconds. Two methane-fuelled support burners which turn on automatically based on the fume temperature ensure that this temperature is maintained, even if there is waste with a low calorific value. Also in the post-combustion chamber, the first fume purification phase is carried out with the injection of an ammonia solution for nitrogen oxide abatement (selective non-catalytic reduction process - SNCR). Once the slag from the combustion reaches the end of the grate, it falls into a tank of water to ensure it is no longer burning, and is subsequently transferred to the storage pit by way of extraction and transport systems.

    3 - Steam generation.
    To produce electricity, after the fumes generated by combustion have passed through the post-combustion chamber, they are sent to a heat recovery boiler (steam generator) which produces superheated steam at a pressure of 47 bar and a temperature of 400°C. The water-tube boiler has the dual function of recovering the heat contained in the fumes and cooling them for the subsequent purification phases. The fumes enter the boiler at approximately 950-1,000°C and exit at approximately 180°C, to then be sent for purification.

    4 - Fume purification.
    The line is equipped with a completely dry fume treatment system, consisting of different devices placed in succession: a first purification stage with the abatement of the solid particulate in the bag filter which uses hydrated lime and active carbon as reagents, and a second stage entailing the injection of reagents such as sodium bicarbonate and active carbon, with an additional passing of the fumes through the bag filter and a final section for the further reduction of NOx with a catalytic system (SCR).

    5 - Cogeneration of electricity and heat.
    The superheated steam generated in the heat recovery boiler is sent to the steam turbine, connected to an alternator. The energy generated by the alternator coupled with the turbine shaft is used to satisfy plant requirements and the remaining portion, approximately 80% of the energy generated, is transferred to the national grid. The energy generation system is set up for the cogeneration of electricity and heat. The heat generated is used to satisfy the requirements of the district heating network.

    • The plant is equipped with a Continuous Emissions Monitoring System (CEMS) which has automatic analysers functioning 24 hours per day to continuously monitor the quality of atmospheric emissions.
      A suitably heated sample probe continuously transports a sample of the gas from the plant´s chimney to the analysis booth where the instrumentation is installed. The sample is put into the Fourier transform infrared spectroscopy (FTIR) analyser, which continuously detects the absorption spectra of the compounds to be measured. A mathematical process is used to compare the spectra with the typical spectra of the substances being investigated. The comparison makes it possible to determine the quantitative values (concentrations) of the elements and compounds analysed.
      Besides the FTIR system, there are other continuous analysers and meters needed to complete the fume analysis by determining other parameters such as: particles, organic compounds, mercury, oxygen, temperature, flow and pressure.
      A data acquisition system (SADE) also continuously provides the values obtained by calculating the half-hourly and daily averages of the concentrations measured, which are compared with the maximum admissible limit values set by the Control Bodies. These data are also provided on the group´s website, where they are automatically updated every half hour.

      Periodic micropollutants self-monitoring - year 2019
      Line 3
      152/6 limits
      Cd+Tl (mg/Nm3)0.000310.030.05
      Hg (mg/Nm3)0.00050.030.05
      Metals (mg/Nm3)0.000540.40.5
      Dioxins (ng/Nm3)0.0000260.050.1
      PAH (mg/Nm3)0.00000450.0050.01
      PCB (ng/Nm3)0.000010.10.1
    Termovalorizzazione dei rifiuti: smaltimento sicuro con recupero di energia
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