Supercritical Carbon Dioxide Circulated EGS Combined with IGCC in - PowerPoint PPT Presentation

Supercritical Carbon Dioxide Circulated EGS Combined with IGCC in New Mexico National Geothermal Student Competition Divya Chandra Caleb Conrad National Renewable Energy Derek Hall Laboratory(NREL) Andrew Weiner Nicholas Montebello The Pennsylvania State University Anukalp Narasimharaju June 22 2011 Vaibhav Rajput Emilia Phelan Ghazal Izadi 1

Overview • Why scCO 2 EGS and IGCC • Overview of the region • Technical Considerations • Environmental Considerations • Economics • Conclusions 2

Problem Statement Resource assessment and utilization of geothermal energy potential of the Rio Grande Rift Basin: A technical overview and economic analysis of a combined EGS-IGCC system with CO 2 as the working fluid 3

Why scCO 2 EGS and IGCC? • Semi Arid Region – Intermountain West • Reduced water usage CO 2 as heat transfer fluid • High geothermal gradients and shallow reservoir • IGCC has low net emissions Question: Is the available water resource being wisely used for power? EGS only: 180kg/sec water =~150MWe actual power output Conventional Coal Power Plant: 180kg/sec water=~400MWe actual power output EGS and IGCC: 180 kg/sec water =~ 650MWe actual power output 4

scCO 2 EGS and IGCC system 5

Enhanced Geothermal Systems - Geology Simulation Power Generation 6 Generalized map of the Rio Grande Rift Basin (Stone 1977)

Enhanced Geothermal Systems - Geology Simulation Power Generation • Structural Geology of the Albuquerque Basin – Albuquerque, NM (Red Star) – Proposed Site (Blue Star) – Located on the East Bank of the Rio Grande River – Exists within the North Albuquerque Bench geologic structure (Russel and Snelson 1994) . 7

Enhanced Geothermal Systems - Geology Simulation Power Generation Geologic and seismic sections illustrating the structural configuration of the southern portion of the North Albuquerque basin (Russel and Snelson, 1994) 8

Enhanced Geothermal Systems - Geology Simulation Power Generation Source Characteristics: • Depth: 3.2 km to 5 km • Temperature: 200 o C • Temperature Gradient: 39 o C/km • Reservoir Rocks: Crystalline Basement • Reservoir Type: Geo-pressured System Available Data: • Seismic Reflection • Existing borehole data  Rock Types  Mud weights  Geophysical logs • Geologic Mapping • Aerial Magnetic Data 9

Enhanced Geothermal Systems - Geology Simulation Power Generation CMG Results Spherical Reservoir Model Results 1000 kg/s Major results from reservoir simulation for a five spot pattern: Water production continues until 30% water saturation in the reservoir is achieved • For initial 50% water saturation and 10 meter fracture spacing, thermal • break through occurs after approximately 33 years For this case water production occurs for the first three years • As fracture spacing increases thermal break through time increases • Similar thermal break through results from prototypical reservoir modeled with • either CMG and SRM 10

Enhanced Geothermal Systems - Geology Simulation Power Generation The evolution of moment magnitude in an EGS reservoir with 200m fracture size Plots of the potential for triggered seismicity relative to injector Potential energy release is defined as E = D s 2 a 3 / G This translates to a Moment magnitude for each event as: log 1.5 9.1 M M 0 s Note that seismicity migrates outwards from injector with development of the reservoir. Maximum magnitude is defined by fracture size. 11

Enhanced Geothermal Systems - Geology Simulation Power Generation 12

IGCC - ASU Gasifier Gas Cleaning Units Power Generation 13

IGCC - ASU Gasifier Gas Cleaning Units Power Generation Gasifier • Nitrogen is used as diluent for gas turbines Oxygen to reduce NOx emissions. • Oxygen is used for gasification of coal. Air ASU • Cryogenic technology is preferred as it can be integrated with other process Nitrogen Turbine Uses cryogenic distillation to separate • oxygen and nitrogen Removes water, CO 2 and hydro-carbons • Most efficient and cost effective • Liquid products • Cryogenic Processing(A.R Smith 2001) 14

IGCC - ASU Gasifier Gas Cleaning Units Power Generation Gasification How it Works Steam Reformation Partial Oxidation C(s) + O 2  CO 2 H 2 O + C(s)  H 2 + CO 2C(s) + O 2  2CO 2H 2 O + C(s)  2H 2 + CO 2 Gas Coal Water Slurry ASU Gasifier Cleanup Pulverized Bituminous Coal Industrial Grey Water Purified Oxygen Stream Slurry Mixer Raw Syngas 15

IGCC - ASU Gasifier Gas Cleaning Units Power Generation Gasification Reactor Entrained Flow Advantages Short Residence Time • High Temperature • Few Coal Constraints • Coal Water Slurry Feed • 16

IGCC - ASU Gasifier Gas Cleaning Units Power Generation 17

IGCC - ASU Gasifier Gas Cleaning Units Power Generation Main Components of Gas Cleanup • Two-stage sour gas shift reaction Water Gas • Hydrolyzes COS to H 2 S Shift • 97% conversion of CO to CO 2 Mercury • Sulfur impregnated activated carbon Removal • 90-95% removal efficiency Acid Gas • Two-stage Selexol process • 99.7% H 2 S removal capacity Removal • 90.3% CO 2 removal at 99.5% purity Claus Process • 95% sulfur removal from H 2 S stream Plant • Tailgas (H 2 , CO 2 ) sent back to AGR 18

IGCC - ASU Gasifier Gas Cleaning Units Power Generation GE H-Class Turbines Exhaust (to stack) Heat-Recovery Steam Generator (HRSG) 171˚C Oxygen ASU 345 psig 381˚C Hydrogen Fuel 31 psig Exhaust (from gas clean-up) 277˚C Nitrogen 345 psig 2400 psig 471˚C 565˚C LP Generator HP IP LP Net Power Output = 548 MWe Cycle Efficiency = 60% Pressure Ratio = 23:1 Gas Turbine Steam Turbines 19

Environmental Considerations Economics • Emission savings – By coupling EGS and IGCC substantial emission savings will be generated – $50 million of government incentives for CCS(carbon capture and sequestration) will be received per year • Sustainable Water Usage – Water Sources • Grey Water/Industrial Water • Coproduced water from geothermal field – Water Management Strategy • Scheduled downtimes for maintenance will occur during known low water periods • Total days of electric generation – 292 days 20

Environmental Considerations Economics Elements of Economic Analysis • Electricity selling price = $0.09/kWh Main • Interest rate = 3% Assumptions • Capacity factor = 80% • Capital cost = $1.7 billion System Costs • Annual O&M = $190 million • Selling 4.7 million MWh / yr Revenue • $1.25 million / yr sulfur value Streams • Possible $50 million / yr for CCS • Present day dollar values for cash flows Net Present • 3 possible scenarios Value Analysis • Payback Time (PBT) for each scenario 21

Environmental Considerations Economics Results of NPV Economic Analysis $6,000 Electricity Inflation 0% with CCS Funds $5,000 Electricity Inflation 0% without CCS Funds Electricity Inflate 1% with CCS Funds $4,000 Net Present Value (Millions of $) $3,000 $2,000 $1,000 $0 0 5 10 15 20 25 30 ($1,000) ($2,000) Time (years) 22

Conclusions • Synergy between scCO 2 -EGS and IGCC – Near-zero emissions system – Reduced water usage on per MW-basis – Partial sequestration of CO 2 • Economic Viability – Thermal break through after ~30 years on par with design life spans of other power plant designs – Short transmission distances to market – Short PBT: 6-8 years Other Benefits • – A low visual and carbon foot print – Coal to Liquid fuel potential from IGCC for various applications 23

Questions 24

Acknowledgments • National Renewable Energy Laboratory(NREL) • Dr Derek Elsworth • Dr Sarma Pisupati • Dr Uday Turaga 25

Environmental Economics Social and Cultural Ownership and Land Use Infrastructure • Water Management: – Grey water and produced water use – Scheduled maintenance during known drought periods. • Aesthetic Landscape Preservation: – Tactical industrial architecture design – Paint schemes • Education Activities: – Water use – Induced seismicity – Affects on the local community 26

Environmental Economics Social and Cultural Ownership and Land Use Infrastructure 27

Enhanced Geothermal Systems - Geology Simulation Power Generation The evolution of moment magnitude in an EGS reservoir with 200m fracture size The elastic strain energy released by failure and the drop in shear stress can be recovered from: 2 3 2 a a 2 1 udA u rdrd p 2 3 G 2 A 0 0 2 3 8( 2 ) G 8(1 ) a 3 (3 4 ) 3 (2 ) G G G Total Energy: T E dV T f i f i Moment magnitude for large fracture: log M 1.5 M 9.1 0 s Number of events which occur during the failure process: E T N event E p 28