Biowaste to power plants at high portions Biosafe TEKES 40181/06

Transkriptio

1 Biowaste to power plants at high portions Biosafe TEKES 40181/06 Fuels T1 Fuel selection, Detailed analysis ÅAU, VTT (J) Harmful and protective compounds T2 Pilot scale experim ents with a BFB reactor: protective reactions VTT To validation Kloorin Kerrostuminen, likaantuminen T5 Mixing of additive in a furnace U Tsinghuan Liuotetut Suoja aineet T3 Furnace sampling (Na, K Cl, UKU Test optimisation Reliable sampling of risky compounds T4 Deposition model (ÅAU) Effective utilisation of biowaste In energy production Martti Aho, VTT, Liekki IV Day

2 Biosafe/ members of the leading group Henkilö Asema Puh. TEKES/TE keskus Mauri Marjaniemi teknologiaasiantuntija Jatta Jussila* VTT prosessit Martti Aho** Var. Pasi Vainikka johtava tutkija tiimin vetäjä Åbo Akademi Mikko Hupa Var. Patrik Yrjas professori TkT Kuopion yliopisto Jorma Jokiniemi: professori Var. Olli Sippula DI Kvaerner Power Jaani Silvennoinen Tutkija Kemira OYJ Jari Kukkonen Tutkija Oulun yks Lassila & Tikanoja Lassi Hietanen Tuotepäälllikkö Helsingin vesi Yrjö Lundstöm Ympäristöpäällikkö *Climbus ohjelman koordinaattori, jakelulistalla ** Projektiyhteenliittymän kokoonkutsuja

3 Background

4 CASE 1. BARK/FOREST RESIDUE Heat transfer surface Cl releases corrosion ALKALI CHLORIDES RISKY COMPOUNDS Lack of protecting compounds Risk description: Cl deposition which can lead to high temperature superheater corrosion Low ash content BARK/FOREST RESIDUE

5 Fouling of superheater tubes

6 Superheater tubes damaged by high temperature chlorine corrosion

7 Optional ways to problem solution

8 CASE 2. PROTECTING POWER OF COAL RISKY COMPOUNS ALKALI CHLORIDES ALKALI PROTECTING REACTIONS SILICATES, SULPHATES PROTECTIVES SULPHUR DIOXIDE, Al SILICATES Problem solution by co firing means: Coal contains sulphur and aluminium silicates: Alkali chloride destruction Possible by a) Sulphation SO3 + 2 KCl+ H2O > K2SO4 + 2 HCl Note: sulphur in SO3 form! b) Alkali aluminium silicate formation: Al2O3*2SiO2 + 2KCl +H2O > M2*Al2SiO3*2SiO2 + 2 HCl FOREST RESIDUE COAL Co combustion Note: Sulphation may need high S mass flow to be effective increasing SO2 emissions

9 New and patented: Effective alkali chloride destruction by additives forming SO3 at critical furnace zones 2MCl + SO3 + H2O > M2SO4 + 2 HCl Na2SO4 K2SO4 HCl SO3 attach Very effective S => small dosages, no increase of SO2 emissions NaCl, KCl

10 This project Utilisation of effective sulphur present in different sludges to alkali chlorides destruction in the boiler furnace Destruction of alkali chlorides with minimum sludge portions and SO2 slip No bed agglomeration allowed Toxic emissions must controlled Note: Emissions limits are determined by the co incineration directive

11 Plant idea Dried and pelletised sludge is transported from selected sources to a particular power plant equipped with a bag filter and chemicals to clean the flue gases The plant has high efficiency (with high steam values, > 500 C steam) The main fuel can be for example forest based biomass and also include biomass components classified to waste (demolition wood, impregnated wood)

12 Workprogramme briefly

13 Goals Main goal: Basis to utilise demanding biowaste in energy production in effective power plants will strengthen Sub goals (serving power plant availability): (a) Improved furnace probing tools for risky compounds (b) Improved control of formation and destruction of risky furnace compounds (c) Utilisation of the protective compounds in sludges

14 Tasks and time schedule

15 Tasks Fuels T1 Fuel selection, Detailed analysis ÅAU, VTT (J) Harmful and protective compounds T2 Pilot scale experiments with a BFB reactor: protective reactions VTT To validation Kloorin Kerrostuminen, likaantuminen T5 Mixing of additive in a furnace U Tsinghuan Liuotetut Suoja aineet T3 Furnace sampling (Na, K Cl, UKU Test optimisation Reliable sampling of risky compounds T4 Deposition model (ÅAU) Effective utilisation of biowaste In energy production

16 Time schedule > T1 x x x x x T2 x x x x x x x x x x x x T3 x x x x x x x x x x x T4 x x x x x x x x x T5 x x x

17 Task 1 Fuels Risky fuels as sources of KCl and NaCl Bark, bark/recycled fuel (REF) Protective sludge with effective sulphur 2MCl + SO2 + ½ O2 + H2O > M2SO4 + 2 HCl where M is K or Na

18 Power of fractionation analysis: instead of element contents it gives information of the reactivity of the elements REF to be used ppmw Biosafe REF By Åbo Akademi Si Al Fe Ti Mn Ca Mg P Na K S Cl Rest HCl Acetate Water Untreated

19 Task2: Reactor 20 kw BFB pilot plant Observation port Gas probe Gas cooling Deposit probe Gas sample Sampling port To stack Temperature control Bag filter Sampling port Heating zone 4 Obervation port/ Deposit probe Sampling port Cyclone Heating zone 3 Tertiary air optional Obervation port Tertiary air optional Tertiary air (preheated) Heating zone 2/ Cooling zone 2 Fuel container 2 Fuel container 1 Additive container Obervation port Heating zone 1/ Cooling zone 1 Obervation port BED made of quarz PC control and data logging system Secondary air (preheated) Primary gas heating Nitrogen Air

20 Tasks 2, 3 related to probing of Cl, S, Na and K compounds dib. air Ejektor ELPI T C Cyclone VTT diluter MFC Ejektor Cooling system Cyclone DLPI Exh nitrogen Ftir & CO 2

21 Task 2 Deposit probing to analysis

22 Further illustration: To: Åbo Akademi 30mm 16mm

23 Results from first tests

24 Cl concentrations at critical positions of the deposit: base fuel: spruce bark 8 Bark alone p % Cl kerrostumassa Tmetal 500 C Tflue gas 850 C Tmetal 500 C Tflue gas. 650 C 2 % enb sludge 1 mixed to bark 0 Kuori FB tulo Kuori FB sivu Kuori FB jättö Kuori VK tulo Kuori VK sivu Kuori VK jättö 2% VKM FB tulo 2% VKM FB sivu 2% VKM FB jättö 2% VKM VK tulo 2% VKM VK sivu 2% VKM VK jättö

25 Cl concentrations in the fine fly ash with different sludges and dosages 6 Klooripitoisuudet välikanavanäytteissä eri polttoaineilla mg/nm µm µm µm µm µm µm <0.03 µm! 2 1! 0 Kuori 2%VKM 4%VKM 6% VKM 8%VKM 4%KEMC Bark alone

26 Conclusion: Even a small portion of sludge mixed to bark destroyed the alkali chlorides in the furnace and prevented Cl deposition to the superheaters during bark combustion Next stage: More demanding startpoint will be used: 10% enb. REF will be mixed to bark Old aspect: Sludges make only harm to the boilers by increasing emissions etc. New aspects: Sludges can protect boiler furnaces!