Research & Development Needs for the Clean Coal Plant of the Future

Transcription

1 Research & Development Needs for the Clean Coal Plant of the Future Michael L. Jones Energy & Environmental Research Center Pittsburgh Coal Conference Pittsburgh, PA University of North Dakota

2 World Energy Consumption by Fuel Type, Quadrillion Btu History Projections Oil Natural Gas 100 Coal 50 Renewables Nuclear

3 The Changing Pattern of Fuel Use in Electric Power Generation (EIA) World U.S. 1970* Coal 41% 36% 34% 46% 55% 52% Hydro and Renewable 22% 21% 21% 16% 11% 9% Nuclear 2% 17% 10% 1% 20% 10% Natural Gas 14% 17% 26% 24% 11% 28% Oil 20% 9% 9% 12% 3% 1% *North America, Japan, and Europe

4 Distribution of Coal Produced in the United States (EIA, 1998) Percent Electric Power Generation 80 Export 8 Industrial 7 Coke Production 4 Commercial 1

5 Coal Use Is Sustainable at Current Levels for 200 Years Coal Reserves, million tons USA Former Soviet Union China Europe Total World Reserves World Consumption (1997) 246, , , , ,211 5,269

6 Coal-Fired Generation The energy future includes coal. Coal will account for over half of U.S. electrical generation through 2020 in the absence of major policy changes due to global warming. The future of coal is advanced technology. Clean Efficient Economical

7 Major Factors in the Choice of Fuel and Generating Technology Government policies deregulation, environmental regulations, and global warming Economic factors resource availability, plant cost, fuel cost, and electric transmission lines New technologies Capital cost Efficiency Environmental control capabilities Technical and economic risks

8 Electric Generating Costs for New Plants, /KWhr Nuclear $3000/kw Plant cost Natural Gas $3/Mcf $7/Mcf Coal Bitumin. Subbitumin. $33/ton $10/ton $15/ton Biomass $40/ton Cost of Fuel Cost of Electricity (COE) Current Technology Advanced Technology* COE with $100/ton Carbon Tax Current Technology Advanced Technology

9 "When I am asked what particular research on coal would be of most practical value to those who have to sell it, equally with those who wish to use it, I have no hesitation in saying: research on the composition of coal. There are many problems with the use of coal which are handicapped at the outset from lack of knowledge of what coal is. The problem of the composition of coal is so complex, however, that reasonably rapid progress cannot be made towards its solution save by a team of skilled research workers devoted to it. I can give no better advice to the controllers of any organization concerned with practical research on coal than that they should collect such a team and set them to work on the problem." Richard Vernon Wheeler (~1920)

10 The task for a coal scientist for practice and industry has three main elements: The knowledge to recognize the problems The knowledge to contribute to their solution The ability to communicate with professional colleagues in very different fields: geologists, mineralogists, mining engineers, and fuel technologists. Van Krevelen, 1993

11 Challenge Industry needs: For lower-cost systems Higher efficiency (even without CO 2 ) Enhanced environmental performance

12 Matching Fuel Properties to System Characteristics

13 Keys to Understanding the Impact of Coal Quality Knowledge of fuel properties and fuel quality impacts on system performance Knowledge of variability of fuel properties

14 General Trends Among Eastern High- Rank and Western Low-Rank U.S. Coals Eastern coals have higher calorific value. Western coals contain more water. Western coals contain more oxygen. Eastern coals contain more iron and less of the alkali elements. Eastern coals usually produce more SO 2 per MMBtu. Western coals contain less organic sulfur. Western coal ash fixes sulfur. Eastern inorganic components are all minerals; western coals contain minerals and organically associated elements.

15 Key Coal Properties Ash characteristics Reactivity of chars Moisture levels Volatile content Metals content Sulfur content Nitrogen content

16 Supercritical Boiler Key coal properties Ash characteristics

17 Ash Overview

18 Transport Reactor Key coal characteristics Char reactivity Moisture content Ash characteristics

19 EERC Transport Reactor Development Unit with L-Valve Modifications Primary Cyclone Disengager Bed Material Charge Hopper Standpipe Hot-Gas Filter Vessel and Ash Hopper Dip Leg Coal Feed Hopper Steam Superheated Quench Systems Air Preheaters L-Valve Steam Manifold EERC MS18901

20 Indirect-Fired Cycle Key coal properties Ash characteristics

21 UTRC HiPPS Schematic Generator Air Gas Turbine Steam Turbine Hot Air Gas Generator Coal Heat Recovery Steam Generator FGD Radiant Air Heater HITAF Convective Air Heater Selective Noncatalytic Reactor Zone Efficiency, 47.3% GT Output, 161 MW ST Output, 150 MW Coal-Gas 65%/35% Slag Ash

22 Challenge for All Systems Is Environmental Control Particulate Primary Precursors secondary NO x Catalysts/Carbnox Blinding SO 2 Control SO 3 control Mercury Major challenge

23 Percent of Total Mercury Percent of Total Mercury Mercury Control Challenge Mercury Speciation vs. Coal Type Mercury Emissions vs. Coal Type * Elemental Oxidized Particulate Elemental Oxidized Particulate Bituminous SubBit Lignite Coal Type 0 Bituminous SubBit Lignite Coal Type *After applying existing scrubber and particulate control technologies

24 Abundance and Forms of Mercury in Flue Gas Coal characteristics Mercury levels/forms Chlorine Inorganic composition or ash chemistry Sulfur System conditions Combustion Temperature Air pollution control system

25 Mercury Transformations 0 Hg (g) Cl/HCl/Cl 2 NO/NO 2 SO 2 /SO 3 Hg 0 Vaporization Chlorination HgCl 2 (g) Sorption Catalytic Oxidation Ash Formations Hg 2+ X(g) Species Hg(NO 3 ) 2 HgO HgCl 2 (g) Hg(p) Species HgCl 2 HgO HgSO 4 HgS HgSe Fuel Combustion Postcombustion

26 Mercury, ppm Mercury, lb/tbtu Comparison of Average Mercury Concentrations in Coal Hg, ppm Hg, lb/tbtu App. Bit. Int. Bit. West. Bit. West. Sub. FU Lig. Gulf Lig.

27 Conclusions The challenge of higher efficiency, low-cost, enhanced environmental performance will not be met with a one size fits all approach. Understanding of fuel quality impacts on the entire system Close attention to matching fuel properties with system characteristics will be required. Variability of coal must be understood to optimize utilization options for the resource.

28 Conclusions Mercury speciation in flue gases Varies with coal composition and flue gas components/temperature. Elemental mercury is dominant form in flue gases with low levels of chlorine. Mercury control challenge is elemental mercury Capture in particulate control systems requires sorbent addition activated carbon ESP 60% control, ESP/baghouse with sorbents >80% control. Capture in scrubbers need for upstream oxidation oxidation catalysts SCR possible but coal dependent. Carbon beds and gold trapping downstream of air pollution control systems.

29 Contact Information Energy & Environmental Research Center University of North Dakota 15 North 23rd Street PO Box 9018 Grand Forks, North Dakota World Wide Web: Telephone No. (701) Fax No. (701) Michael L. Jones Associate Director Industrial Relations and Technology Commercialization