MSW fjred indirect combined cycle plant: A novel solutjon to waste management and power for India Dr. Sudip Ghosh Associate Professor Department of Mechanical Engineering Indian Institute of Engineering Science and Technology, Shibpur Howrah -711103, West Bengal, India 1
”A world in transformation” Large-scale shifus in the global energy system : - Rapid deployment of clean energy technologies - Falling cost of renewables - Solar, Wind, Hydro and Biomass lead the RE campaign ”The boom years for coal are over ” – World Energy Outlook 2017 ”Global energy demand is 30% higher by 2040” – WEO 2017 We are on a hurried path of changes IIEST/SG 2
Issues with Renewables Diverse sources: Sun, air, water, biomass, geothermal Equally diverse technologies for energy conversion Varied resource mix at country or region levels Difgerent levels of development and maturatjon Most technologies at low conversion effjciency Technologies have difgerent carbon emission implicatjons Not yet fjt to cater to base load contjnuous generatjon No uniform formula to decide right energy mix IIEST/SG 3
Waste Conversion: Clean-Tech! Waste conversion fits in well as a competing clean technology Municipal Soloid Waste (MSW) is considered as local sources for a city or municipal area (self-sustaining too, in the sense that city keeps on generating resources on daily basis, generation volume predictable ) Traditional biomass conversion technologies like combustion and gasification, also apply to MSW. Besides that, MSW conversion has inherent disposal solution IIEST/SG 4
Present work Here we present the confjguratjon, thermal design and analysis of a combined cycle plant, fuelled by segregated municipal solid waste (MSW). Energy, exergy and environmental (3-E) analysis along with optjmizatjon study of the plant is carried out and reported. IIEST/SG 5
Present work We took the city named Chandanagar (22.87°N, 88.38°E), a highly populated municipal area, located near Kolkata and governed by a municipal corporatjon, as the case study. As per the report of the Chandanagar Corporatjon, about 46 tonnes of raw waste is generated on a daily basis (2017-2018) IIEST/SG 6
Waste disposal IIEST/SG 7
MSW Analysis Proximate Ultimate LHV LHV actual Analysis Analysis theoretical C: 40-50 % Volatile matter: 13566.7 H: 5.5-6.6 % 50-80 % (kJ/kg) O: 30-35 % Fixed carbon: N: 0.6-1.2 % 10-18 % S: 0.1-0.5 % Ash: 6-12 % Cl: 0.9-1.7 % Heavy metals 14668.77 Ash- Rest Cd:1 % (kJ/kg) Cr: <10 % Hg: 0.002% Pb: 39% As: <1% Se: <0.005% IIEST/SG 8
Gasification: A versatile route IIEST/SG 9
Gasification A thermo-chemical process in which solid biomass is partially oxidized to yield combustible producer gas. Major components of producer gas: CH 4 , H 2 , CO, CO 2 , H 2 O and N 2 . LHV of Producer gas 4-6 MJ/N m 3 (gasifying agent Air) LHV of Producer gas 12-18 MJ/N m 3 (gasifying agent Steam/Oxygen) IIEST/SG 10
Gasifier-Gas Engine: A popular generation option IIEST/SG 11
Disturbing Issues Low Overall efficiency (16-20%). Extensive gas cleaning and cooling requirement. High cost of operation and maintenance. IIEST/SG 12
Gas Cleaning IIEST/SG 13
Cleaning needs for ICE/GT Impurities Unit IC Engines Gas Turbines Particulates mg/Nm3 <50 <30 (size) (µm) (<10) (<5) Tars mg/Nm3 <100 <10.0- Alkali metals mg/Nm3 <0.1 <0.1 N species ppm(v) - <50 S species ppm(v) <20 <20 Halides ppm(v) - <1 IIEST/SG 14
Replace Fired Engine/GT with indirect Heating Combustor Heat No fired GT Exchanger No corrosion and erosion , particulate deposition : GT safe No need of gas cooling & cleaning Clean GT exhaust; recyclable Operates on low-cost and dirt fuels IIEST/SG 15
Externally Fired Combined Cycle SEG Waste CC Segregated HX materials AT C1 A F HRSG ST LP ST HP SUP RH Stack EVAP ECO C2 COND P IIEST/SG 16
MSW Combined Cycle: Model Net power output from the plant is calculated as W {( W W ) ( W W W ) } W . net GT C 1 gen 1 HPST LPST P gen 2 C 1 gen 3 Overall electrical effjciency of the plant is calculated as W net m . LHV overall waste waste Annualized electricity delivered (MW e h) by the plant is determined as P W . CUF . 8760 .( 1 L ) / 1000 annual net distributi on network CUF represents Capital Utjlizatjon Factor (taken as 0.5, as the plant operatjng hour is 12 h a day basis) IIEST/SG 17
MSW Combined Cycle: Model Exergetjc effjciency of the plant as well for the plant components is calculated as: Ex product ex Ex fuel The specifjc fuel exergy is given by 1 . 044 0 . 016 ( H / C ) 0 . 34493 ( O / C ).( 1 0 . 0531 . H / C ) Ex . LHV waste waste 1 0 . 4124 .( O / C ) Environmental performance of the plant is evaluated via determining the specifjc CO 2 emission as well as the sustainability index (SI). N . 44 . 3600 1 CO SI 1 2 2 CO ( ) W exergetic , plant net IIEST/SG 18
Parametric Assumptions Component Parameter/s Value Ref Operating pressure (bar) 1.013 Mondal & Ghosh 2017 [21] CC Pressure drop (bar) 0.05 Datta et al., 2009 [22] Pressure drop at air side 3 % of inlet pressure HX Datta et al., 2009 [22] Pressure drop at gas side 1.5% of inlet pressure C1 Isentropic efficiency (%) 87 Mondal & Ghosh 2017 [21] C2 Isentropic efficiency (%) 90 Isentropic efficiency (%) 86 GT Mechanical Efficiency (%) 95 Isentropic efficiency (%) 85 HPST Inlet pressure (bar) 18 Mondal & Ghosh 2017 [21] Inlet temperature ( o C) 320 Isentropic efficiency (%) 85 LPST Inlet pressure (bar) 5 (18% of HP) Inlet temperature ( o C) 300 Pinch point temperature difference 10 HRSG Mondal & Ghosh 2017 [21] of the Evaporator ( o C) Cond. ST exhaust pressure (bar) 0.1 Mondal & Ghosh 2017 [21] P Isentropic efficiency (%) 85% Other assumptions Environmental damage cost due to CO 2 emission 0.0145 $/kg Jana & De, 2015 [23] Environmental damage cost due to land filling 12.8 Euro/t of waste Rabl et al., 2008 [9] Plant operating hours 12h-a day basis Loss in transmission line 5% IIEST/SG 19
Base Case Performance Parameter Unit Value Net GT output kWe 2327.31 ST1+ST2 output kWe 913.28 Net GT-ST work ratio ---- 3.44 Net electrical efficiency % 44.236 Annualized electricity delivered MWh 12498.73 Electrical specific CO 2 emission kg/kWh 0.96 Sustainability index ---- 1.62 Environmental damage cost due to CO2 $/Y 168845.6 emission from the plant Environmental damage cost due to land filling $/Y 247148.8 Environmental savings compared to land filling $/Y 78303.2 IIEST/SG 20
Parametric performance 4.0 o C 46 TIT=900 o C TIT=1000 3.5 Net Plants' Electrical Efficiency (%) o C TIT=1100 44 Net GT-ST Work Ratio 3.0 42 2.5 40 2.0 o C TIT=900 38 o C TIT=1000 1.5 o C TIT=1100 36 1.0 4 6 8 10 12 14 16 4 6 8 10 12 14 16 Topping Compressor Outlet Pressure (bar) Topping Compressor Outlet Pressure (bar) Energetjc performance at varying pressure ratjon of GT IIEST/SG 21
Parametric performance 42.18% 5.43% 2.36% 9.13% 2.56% 1.77% 2.59% C1+C2 CC Loss ST1+ST2 Useful GT 33.98% Others HX Exergy destructjon and useful exergy IIEST/SG 22
Parametric performance 94.5 94.0 65 93.5 Exergy Efficiency of the HX (%) 64 Exergy Efficiency of the CC (%) 93.0 63 92.5 62 92.0 61 91.5 60 91.0 o C o C TIT=900 TIT=900 o C o C TIT=1000 TIT=1000 59 90.5 o C o C TIT=1100 TIT=1100 90.0 58 4 6 8 10 12 14 16 4 6 8 10 12 14 16 Topping Compressor Outlet Pressure (bar) Topping Compressor Outlet Pressure (bar) Energetjc performance of CC and HX varying pressure ratjon og GT IIEST/SG 23
Parametric performance 1.08 1.68 o C TIT=900 o C TIT=900 o C TIT=1000 1.65 e h) o C TIT=1000 1.04 o C TIT=1100 o C TIT=1100 2 Emission (kg/kW 1.62 1.00 Sustainability Index 1.59 0.96 1.56 0.92 1.53 Specific CO 1.50 0.88 1.47 0.84 4 6 8 10 12 14 16 4 6 8 10 12 14 16 Toppong Compresssor Outlet Pressure (bar) Topping Compressor Outlet Pressure (bar) Environmental performance: Specifjc CO 2 emission as well as the sustainability index (SI). IIEST/SG 24
Conclusion The study confjrms that, such kind of small scale ofg-grid plant can be benefjcial for both sustainable MSW management as well as generatjon of electricity from MSW to meet the utjlity power need of the city. It is observed that, the plant can produce 3 MWe net electrical output at an overall effjciency value of about 44% giving annual productjon of about 12500 MWh. The specifjc CO 2 emission is 0.96 kg/kWh and SI value is 1.62 at base case. Furthermore it is observed that, annual environmental damage saving is about 78303$ at base case. IIEST/SG 25
Thank you Contact: sudipghosh.becollege@gmail.com ghoshsudip@mech.iiests.ac.in IIEST/SG 26
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