Air Quality Control Systems and Components - Hitachi Power ...

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Flue Gas DesulphurizationWell within the StandardsHPE makes use of unhydrated lime and the limestone gypsum process for flue gasdesulphurization in power plants. For these technologies we have proven specialists whocan look back on a long track record in flue gas desulphurization.Thanks to these technologies all the emission standards possibly affected by the flue gasscrubber are reliably kept to or fall well within them. Gypsum can be recovered as the endproduct for further industrial utilization. In line with customer preferences, Hitachi Power Europeeven supplies the flue gas desulphurization systems (FGD) on a turnkey basis. Finally, thegypsum that arises is sent to the manufacturing industry.Limestone gypsum processOn account of its simplicity, the limestone gypsum process has proved its worth across theworld in flue gas desulphurization. This process involves sulphur dioxide (SO 2 ), hydrogenchloride (HCl) and hydrogen fluoride (HF) being precipitated in an alkaline scrubbing liquid.The limestone-induced absorption gives rise to a high-grade gypsum product, which isnoticeable for its degree of whiteness. If required by the customer, the unhydrated lime processcan also be used.Separate stackWith the cleaning over, the flue gas can be emitted directly to the atmosphere via the coolingtower or separate stack on the absorber. Which of these two processes is more cost-efficientis calculated on the basis of stack height and number of power plant units. In matters ofexisting plant refurbishment, use can be made either of the original flue gas path or a mountedstack.Diagram of FGD processCooling towerFlue gasEl.precipitatorAbsorberAsh siloOxidation airAbsorber residueemptying tankProcess waterPulverized limestonePulverizedlimestone siloTo waste watertreatmentWaste waterGypsumTo gypsumstorage area6
HPE Absorber Absorber inletFlue gas Absorber sump (Tank)Normal residence time 4 minutes inGermany, but it can be flexibly designed. Spray nozzlesUp-and-down spray nozzles; mostly hollowcone, only near the wall maybe change tofull cone. Spray levelsNumber of spray levels depends on fuel.For inter national coal and emissionrequirements as requested in Germany:4 levels plus space for retrofit of 5th level. Mist eliminatorDepending on the allowable dropletcontent downstream of the mist eliminator2 or 3 stages. Absorber outletHorizontal or vertical outlet will be selecteddepending on downstream equipment.Intelligent TechnologyThe flue gas enters the lower part of the HPE absorber and ascends through the absorptionsection. Intelligent technology ensures that the number of nozzle levels of the contact zoneand positioning of their nozzles are adjusted to the desired absorber collecting efficiency.Up-to-the-minute computations of flue gas entry angle and speed make it possible forturbulence to be kept well down inside the absorber. A large and a fine droplet separatorretain the fine droplets in the flue gas before the cleaned gas leaves the absorber. The actualtransition from pollutant gas to liquid occurs in an intensively intermixed gas / liquid contactzone.Air Quality Control Systems 7
Page 2 and 3: Hitachi Power EuropeFrom Coal to El
Page 4 and 5: Experience and Competence in Enviro
Page 8 and 9: Nitrogen Oxide Reduction (DeNO X )C
Page 10 and 11: Mercury ReductionAlways One Step Ah
Page 12 and 13: CO 2 CapturePost-combustion Capture
Page 14 and 15: Post Carbon Capture Plant Integrati
Page 16: © Hitachi Power Europe GmbH /06.20

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