Definition according to EPA. “Useful energy” – Mechanical, thermal
Operation of any fuel-fired power generating equipment results in emissions of exhaust gases.HRSG/Cogeneration’s main focous is its efficiency.Our plant’s main pollutant of concern was Nox.The environmental permitting requirements for on-site generation impose restrictions on emissions of NOx, SOx, CO, and particulates because of their contributions to smog and acid rain.SOx and PM are primarily dependent on the fuel used."Thermal" NOx emissions are a consequence of the high combustion temperatures; the higher the temperature level, the greater the formation rate for NOx."Fuel based" NOx emissions are negligible in systems using natural gas, but they can be a significant source of pollution when fuel oil is used.SOx formation is a consequence of sulfur contained in the fuel and is insignificant for natural gas but must be considered when fuel oil or other fuels are used.
By capturing and utilizing heat that would otherwise be wasted from the production of electricity, CHP systems require less fuel than equivalent separate heat and power systems to produce the same amount of energy.Because less fuel is combusted greenhouse gas emissions are reduced.Gas turbines are among the cleanest fossil-fueled power generation equipment commercially available. For gas turbines at higher loads, higher NOx emissions occur due to peak flame temperatures. At lower loads, lower thermal efficiencies and more incomplete combustion occurs resulting in higher emissions of CO and VOCs.
Gas turbines: Pollutants such as SOx and particulate matter (PM) are primarily dependent on the fuel used. Microturbines: Are designed to achieve low emissions at full load and emissions are often higher when operating at part load. Reciprocating engines: Pollutants such as SOx and PM are primarily dependent on the fuel used. The sulfur content of the fuel determines emissions of sulfur compounds, primarily SO2. Steam engines: Emissions from steam turbines depend on the fuel used in the boiler or other steam sources, boiler furnace combustion section design, operation, and exhaust cleanup systems.Fuel cell systems have inherently low emissions profiles because the primary power generation process does not involve combustion In general, SOx emissions are greater when heavy oils are fired in the turbine.
Most of these technologies reduce NOx Selective catalytic reduction (SCR) or catalytic combustion can further help to reduce NOx emissions by 80 percent to 90 percent and CO by approximately 90 percent. SCR: Ammonia is injected into the flue gas and reacts with NOx in the presence of a catalyst to produce N2 and H2O. Microturbines are designed to achieve low emissions at full load and emissions are often higher when operating at part load. Additional NOx emissions removal from catalytic combustion in microturbines is unlikely to be pursued in the near term because of the dry low NOx technology and the low turbine inlet temperature.
FGD can provide up to 95 percent SO2 removal Regenerable FGD converts the waste product into a product that is saleable, such as sulfur or sulfuric acid. NSCR is the basic automotive catalytic converter process that reduces concentrations of all three major criteria pollutants – NOx, CO and VOCs. Nox and Co reduced >90%, VOC’s – 80% SCR- selectively reduces NOx to N2 in the presence of a reducing agent FGR is the most effective technique for reducing NOx emissions from industrial boilers
Air pollution related to cogeneration power plants
Cogeneration Power Plants<br />1<br />12/1/2010<br />TeampHly Ash<br />
Table of Contents<br />Introduction<br />Basic Components<br />How does it work?<br />Technologies<br />Health and Environmental Impacts<br />Emissions<br />Control Devices<br />Regulations<br />Conclusions<br />2<br />
Introduction<br />Cogeneration<br /><ul><li>Generation of multiple forms of useful energy in a single integrated system</li></ul>Power to Heat Ratio<br />Advantages<br /><ul><li>High fuel efficiency
Exhaust captured for various processes</li></ul>4<br />
Basic Components<br />Combustion Chamber<br />Prime Mover<br /><ul><li>Turbine that transforms thermal or pressure energy to mechanical</li></ul>Generator<br /><ul><li>Converts mechanical energy to electrical </li></ul>Heat Recovery<br /><ul><li>Captures exhaust for steam generation, process drying or building cooling</li></ul>Electrical Interconnection<br />5<br />
How does it work?<br />http://www.youtube.com/watch?v=uXLUoqzlT2k&feature=related<br />Green Peace UK<br />6<br />
Effects of CO2<br />16<br />Large contributor to global warming<br />More severe weather systems<br />Increased air pollution<br />Saltwater intrusion<br />Damages ecosystems<br />Increases spread of disease<br />
Control Technology<br />Control peak flame temperatures<br />Feature lean premixed burners <br />With no post-combustion emissions control <br />With selective catalytic reduction (SCR) <br />Feature lean premixed burners<br />With no post-combustion emissions control<br />Gas turbines<br />Microturbines<br />
Control Technology<br />Control of peak flame temperature <br />Non selective catalytic reduction (NSCR)<br />Selective catalytic reduction (SCR)<br />Flue gas desulphurization (FGD) <br />Flue gas recirculation (FGR)<br />Reciprocating engines<br />Steam Turbines<br />Control technologies and emitted pollutants depend on the fuel selected for combustion.<br />
Progress Energy Cogeneration <br />28<br />Pollutants of concern<br />NOx<br />CO2<br />Emission standards<br />NOx: <br />25 ppm, 39.6 lb/hr<br />Plant has two hours to get within these standards<br />
State Regulations (FDEP)<br />29<br />62-296.405 Fossil Fuel Steam Generators with More Than 250 Million Btu Per Hour Heat Input. <br />Visible emissions – 20 percent opacity except for either one six-minute period opacity shall not exceed 27 percent, or one two-minute period per hour during which opacity shall not exceed 40 percent.<br />Particulate Matter – 0.1 pound per million Btu heat input, as measured by applicable compliance methods. <br />Sulfur Dioxide, as measured by applicable compliance methods. <br />Emissions units burning liquid fuel. <br />2.5 pounds per million Btu heat input. <br />Emissions units burning solid fuel. <br />6.17 pounds per million Btu heat input. <br />Nitrogen Oxides (expressed as NO2) – as measured by applicable compliance methods. <br />62-296.406 Fossil Fuel Steam Generators with Less Than 250 Million Btu Per Hour Heat Input<br />Visible Emissions – Same as 62-296.405<br />Particulate Matter – Best available control technology. <br />Sulfur Dioxide – Best available control technology.<br />62-296.702 Fossil Fuel Steam Generators. <br />Particulate Matter - 0.10 pounds per million BTU <br />Visible emissions the density of which is greater than 20 percent opacity <br />
National Ambient Air Quality Standards(NAAQS)<br />30<br />
Conclusions<br />32<br />Cogeneration has many benefits over traditional processes<br />The type of fuel and system used varies greatly and depends on<br />Location<br />Capital<br />Regulations<br />Cogeneration is becoming more popular<br />