PROJECT DESCRIPTION - GENERAL DATA OF THE PROCESS

Transcription

1 PROJECT DESCRIPTION - GENERAL DATA OF THE PROCESS 1. TERMS AND CONDITIONS 1. GENERALS Bionerga has decided to build a new Biosteam plant in Ravenshout Beringen, next to an international chemical company, called Borealis. Bionerga already operates two waste-to-energy plants : One in Houthalen-Helchteren, dating from 1984, and One in Ostend, dating from Bionerga will coordinate the construction of the new Biosteam plant through Biostoom Beringen nv, an affiliate of Bionerga still to be established. Figure 1: Site location The new Biosteam plant in Beringen must produce high-quality steam through the incineration of non-hazardous and non-recyclable waste and subsequently make optimum use of this steam by dynamic heat deliveries and an efficient conversion into electricity. The Biosteam plant should meet the criteria for an R1-installation conform the European Waste Framework Directive 2008/98/EG and should fulfill to all applicable legislation (emissions, noise, ). The installation will consist of one incineration line comprising (but not limited to) :

2 Waste reception, Bunker, Cranes, Hopper, Grate, Deslagger; Steam boiler, Steam circuit, Steam turbine and generator set, Flue gas treatment (dry), On-line emission measurements (raw and clean), ID-fan, Chimney, Visualisation and automation, Instrumentation, Low, medium and high voltage, Transformer stations, Off-gas processing, Heat delivery towards Borealis/third parties, Industrial buildings, Infrastructure, Bionerga puts the Biosteam plant in Ostend (Biostoom Oostende) forward as the reference. The new Biosteam plant in Beringen must be equal to or better (e.g. in equipment, redundancy, quality, finishing, ) than the Biosteam Plant in Ostend. Profound standardization within the new Biosteam plant, resulting in for instance a lean spare parts philosophy, is intended. Additional standardization with the existing plant in Ostend as well as supplier s optimizations are fully encouraged. Specific requirements in which the new Biosteam plant in Beringen differs from the Biosteam Plant in Ostend, for instance an SCR instead of an SNCR, an additional ESP, heat delivery towards Borealis, will be highlighted during the individual clarification meetings and in due time. The figures mentioned in this document only serve to give an overall idea of the specifications of the new Biosteam plant. For indications concerning minimal, nominal and maximal operating conditions as well as for measuring points, modalities, scope of delivery, a reference is made to the technical requirements. 2. BOREALIS Today, Borealis produces its entire steam requirements by their own steam boilers which are partly fired with off-gases (a mixture of hydrocarbons) from their own production process and partly with natural gas. The new Biosteam plant in Beringen will be designed in order to realize a close collaboration with Borealis processes. Bionerga will operate as utility provider for Borealis. Borealis produces

3 polypropylene for the packaging of food products, amongst others. Therefore, all chemicals used for the demin water production and steam conditioning (e.g. ph controller, oxygen scavenger, agent for water softening, cleaning liquids, preservatives, ) need to be food approved. Borealis, however, will remain responsible for their own steam back-up. Therefore timely communication of (expected) steam supply interruptions by Bionerga will play an essential role in the collaboration with Borealis. The new Biosteam plant of Bionerga must be designed to produce steam and electricity by the incineration of waste (and off-gases if applicable) as efficient as possible. It will produce a net heat production of 76 MWth in a steam boiler by the incineration of waste (86 MW input). Due to the HPS (high pressure steam) delivery towards Borealis the minimum steam conditions should be 43,5 bar(a) and 400 C. The supplier is asked to optimize as much as possible the different operating scenarios. The temperature/pressure correlations mentioned in this document are only indicative and are part of the optimizations to be proposed by the supplier. However, all temperatures and pressures related to Borealis are to be considered as fixed. 3. WASTE INPUT The following non-recyclable waste streams (with an average estimated lower heating value (LHV) value of circa 12,5 MJ/kg) will, on average, be incinerated : Waste stream Origine % Household waste 40% Similar industrial waste 30% Bulky waste 15% High calorific waste (cfr. SRF) 15% Table 1: Indication of the average waste mix to be treated. Based on Table 1 it can be concluded that standard household waste only represents less than 50% of the entire waste mix and more than 50% of the waste mix consists of similar industrial waste (including non-hazardous clinical waste), high calorific waste (cfr. SRF, solid recovered fuel) and bulky waste (shredded). The nominal LHV of the waste mix is estimated to be 12,5 MJ/kg, with a minimum of 9 MJ/kg and a maximum of 16 MJ/kg. The grate of the new Biosteam plant must be designed to treat 24,8 tons of non-recyclable waste per hour nominally.

4 4. STEAM DELIVERY Bionerga will deliver live steam to Borealis. Borealis steam requirement fluctuates continuously and is sensitive towards seasonality, e.g. more during winter and less during summer. Even during site shut-downs Borealis might take off steam. In relation to its steam off-take, Borealis consumes, on average, 12 t/h which does not return as condensate. Besides live (minimum 43,5 bar(a) and 400 C) steam towards Borealis the Biosteam plant should be designed to also efficiently deliver steam at medium (13 bar(a)), low (7 bar(a)) and low-low (3 bar(a)) pressure for future steam deliveries towards third parties, including a district heating network. 5. DEMIN WATER Besides steam, Bionerga will also deliver demin water to Borealis. For demin water to Borealis a minimum availability of 99,95% is required. 6. OFF-GASES If Borealis off-gases (a mixture of hydrocarbons, 11 MW on average) are not fired in the steam boilers of Borealis, the off-gases will be supplied to Bionerga. Bionerga then aims to utilize these offgases as efficient as possible in multi-fuel (start-up) burners, but optimizations from the supplier are welcomed. 7. ELECTRICITY All residual steam which is not delivered to Borealis, or any other (future) heat offtaker, goes to Bionerga s steam turbine and generator set converting the energy into electricity at 10,34 kv. Nonetheless, the turbine should be dimensioned for the entire steam production of the steam boiler. Before injecting the electricity produced on Borealis Closed Distribution System (CDS), it needs to be stepped up to 150 kv (cfr. high voltage grid Elia) with a transformer. The transformer will be located on Borealis premises. For this scope of works, the design requirements for the medium and high voltage of the CDS of Borealis need to be taken into account. For works on Borealis premises only contractors prior approved by Borealis are allowed. An accreditation procedure will be made available in due time.

5 8. PROCESS BLOCK DIAGRAM Figure 2: Block diagram The block diagram shows the processes which are selected for the new Biosteam plant.

6 The waste is discharged and stored into the fuel bunker. An automatic fuel crane and grab keeps the unloading pits empty and transports the waste into the hopper of the grate furnace, where the incineration of the waste is controlled by the injection of primary and secondary air underneath, respectively above, the grate. The Contractor chooses the type of grate which most fits the fuel / waste mix presented. Bottom ashes fall into the deslagger and are transported accordingly towards the ash bunker. From the ash bunker, they can be transported into trucks by means of a slag crane and grab system. Boiler ashes from the superheaters are removed by rapping devices. Pneumatic or pendulum valves ensure transport of the ashes from the deashing hoppers towards chain conveyors. The boiler is a water-tube boiler fit for the required steam parameters and capacities. All necessary equipment, devices, instruments and appendages (desuperheaters, safety valves, control valves, ) are to be foreseen to secure a flawless functioning of the dynamic steam flow. The steam turbine-generator set is to be foreseen and completely integrated in the steam condensate circuit, including control and lube oil system, vacuum system, to condense the exhaust steam from the steam turbine, an aero-condensor is put forward. Other than the internal necessity for steam, the supplier must also foresee the possibility for the delivery of steam at different pressures as well as hot water, and equips the steam turbine as such, however without supplying the heat exchanger or any piping thereof. It should be ensured that there is sufficient space available in the turbine room. The water demineralization plant makes primarily use of ground water, potentially supplemented by rain water, and if necessary replaced by city water with the possibility to deviate to canal water. Besides the suppletion of the steam boiler s blow-down, an important volume of demin water ( = 16 m³/h nominally) should be supplied to Borealis to compensate for Borealis lost steam and process needs. Therefore, an important unit is necessary that can supply 20 m³/h demineralized water to Borealis and additionally providing the Biosteam plant need of demineralized water as suppletion water. Borealis has a continuous need of demineralized water even when the Biosteam plant of Bionerga is shut down. Therefore, the demineralization unit should be dimensioned for an availability of 99,95%, e.g. only 4 hours a year no supply of demin water is tolerated. The supplier should design the demineralization unit with the necessary redundancy measures and/or buffer to guarantee this high availability. The salty waste water (brine) of the demineralization plant is used internally as much as possible amongst others, to moisturize the bottom ashes, for the water sprayers, etc. The remaining brine is to be discharged into the Winterbeek. The flue-gas treatment consists of the following equipment : an electrostatic precipitator removes most of the fly ashes from the flue gases. These fly ashes are to be stored in a separate silo. sodium bicarbonate and activated carbon/lignite are injected into a reactor (dry). The necessary silos and dosing systems for these chemicals are to be foreseen.

7 a bag house filters removes residues (fly ashes and reacted chemicals) from the flue gasses. Storage of this residue is separate from the fly ashes that are separated by the ESP. a selective catalytic reduction (SCR) denox with injection of ammonia. The ammonia tank and dosing system are also to be foreseen, taking into account the ATEX regulation. Continuous emission monitoring devices for flue gas analysis in the chimney are to be installed. An emission monitoring of the raw gases is to be foreseen downstream the economizers. In between the SCR denox and the induced draft fan, an external economizer-2 is requested as mandatory option, which Bionerga will approve after economic consideration. 9. LICENSES Both the environmental license and the building permit have already been obtained. However, due to an appeal by a local action committee against the environmental license, the environmental license and the building permit are suspended. Other licenses that have to be taken into account amongst others : Elia study, Soil investigation Mobility study Deforestation license 10. TIMING An execution period (from Financial Close until 1 st provisional acceptance) of 28 months is strived for. The suppliers are, however, responsible for the basic and detailed project planning. Close communication between different suppliers will be required.