1. T. Gundersen E&M 01 Process, Energy and System Energy & Environment Special Lecture on Energy & Environment Clean Process Technology (Ch. 28 in R. Smith) Classes of Waste (Process & Utility) Environmental Impacts from Energy Usage Energy/Exergy & Component/System Efficiencies Actions to mitigate Greenhouse Effects (Energy21) How can TEP4215 Energy & Process (PI) Contribute Process EnvironmentEnergy Process Integration

2. T. Gundersen E&M 02 Process, Energy and System Energy & Environment Clean Process Technology – Some Ideas (Ref.: Robin Smith, Chemical & Process Integration, Ch. 28) Environmental Issues (similar to Heat Integration) are often considered late in the Design Process The Result is often “End-of-Pipe” Solutions Clean Process Technology represents an Opposite Approach similar to Process Integration thinking: Minimize Waste at Source − Examples:  Choose Reactions Paths that avoid harmful Chemicals being produced as byproducts  Keep harmful Chemicals “inside the loop” by combining producing and consuming Reactions  Closing Processes as in Pulp & Paper

3. T. Gundersen E&M 03 Process, Energy and System Energy & Environment Sources of Waste from the Process Industry Types of Process Waste:  Waste Byproducts, Purge Streams, etc. Sources of Process Waste:  Reactors (byproducts, used catalysts, etc.)  Separation & Recycle Systems (inadequate recovery and recycle of valuable materials)  Process Operations (start-up, shutdown, product changeover, equipment cleaning, etc.) R SHU R + S : Process Waste H + U : Utility Waste

4. T. Gundersen E&M 04 Process, Energy and System Energy & Environment Sources of Waste from the Process Industry Types of Utility Waste:  Gaseous Combustion Products (CO 2, SO x, NO x, Particles)  Aqueous Waste from BFW (Boiler FeedWater) Treatment  Waste from Water Systems Sources of Utility Waste:  Hot Utilities (incl. Cogeneration)  Cold Utilities and Water Systems R SHU R + S : Process Waste H + U : Utility Waste

5. T. Gundersen E&M 05 Process, Energy and System Energy & Environment Sources of Waste from the Process Industry Our Focus in these Lectures:  Environmental Impacts from Energy Consumption Remember to take a Systems Approach:  Local Emissions vs. Global Emissions  Producing or importing Electricity? R SHU R + S : Process Waste H + U : Utility Waste

6. T. Gundersen E&M 06 Process, Energy and System Energy & Environment Environmental Impacts from Processes including their Use of Energy Various Kinds of Waste Material Heavy Metals CO and CO 2 NO x and SO x CH 4, NH 3 and other volatile compounds Particles (“Particulates”) VOC (Volatile Organic Compounds) Heat (or Cooling) Wastewater Using scarce Freshwater Resources

7. T. Gundersen E&M 07 Process, Energy and System Energy & Environment Environmental Design for Atmospheric Emissions (Ref.: Robin Smith, Chemical & Process Integration, Ch. 25) Urban Smog (Los Angeles, Mexico City, Lima, Shanghai)  Photochemical Reactions  VOCs + NO x + O 2  O 3 (Ozone) + Other Photochemical Pollutants (Aldehydes, Peroxynitrates, etc.) Acid Rain  Natural Precipitation is slightly acidic with pH around 5-6  Carbonic acid from dissolved CO 2  Sulfuric acids from natural emissions of SO x and H 2 S  Human Activity can reduce pH to 2-4  Mainly caused by emissions of SO x  This is a primarily a local environmental problem  Can be a regional problem (from UK to Norway)

8. T. Gundersen E&M 08 Process, Energy and System Energy & Environment Environmental Design for Atmospheric Emissions (Continued) Ozone Layer Destruction  Lower Levels of the Atmosphere: Ozone is harmful!  Upper Levels: Ozone essential; it absorbs ultraviolet light!  Destruction is due to Oxides of Nitrogen and Halocarbons The Greenhouse Effect  CO 2, CH 4 and H 2 O present in low conc. in the atmosphere  Reduces emissivity and reflects some of the heat radiated by Earth.  Keeps the Earth warmer − a prerequisite for Life as we know it  This Balance can be disturbed  Global Warming  Burning Fossil Fuels (increased emission of CO 2 )  Large Scale harvest of Forests (reduced absorption of CO 2 ) The largest Volume of Atmospheric Emissions from Process Plants is due to Combustion

9. T. Gundersen E&M 09 Process, Energy and System Energy & Environment Actions that reduce the Environmental Impacts from Energy Consumption Statement: The most “Green” Energy is the Energy that is not used  Process Integration increases Energy Efficiency and results in Energy (in various forms) not being used  Investment in Equipment may cause use of Fossil Fuel based Energy elsewhere (considering LCA) More comprehensive List of Actions  Use less Energy (vs. “Standard” of Living)  Increase Energy Efficiency  Increase Process Efficiency  Switch between Fossil Fuels  Switch from Fossil Fuels to Renewables

10. T. Gundersen E&M 10 Process, Energy and System Energy & Environment “Energi21” − National Strategy for R&D, Demonstration & Commercialization − Energy in the 21 st Century The Vision of Energi21  Norway: Europe’s leading Energy and Environment- Conscious Nation − from a National Energy Balance to Green Energy Exports To realize this Vision: 5 Priority R&D Areas  Efficient Use of Energy (Industry/Transport/Buildings)  Climate-friendly Power  CO 2 -neutral Heating  An Energy System to meet the Needs of the Future  Desirable Framework Conditions for R&D

11. T. Gundersen E&M 11 Process, Energy and System Energy & Environment Energy Consumption (TWh) in Norway by Sector in 2007 (Total: 813.5 PJ) Other Sectors: Private household (20.0%), Community Consumption (13.7%) and Fishing/Agriculture (3.6%) 37.3% 35.1% 27.6%  The Course “Energy & Process” makes Sense !! T(erra) = 10 12

12. T. Gundersen E&M 12 Process, Energy and System Energy & Environment Energy Consumption (TWh) in Norwegian Industry in 2007 (Total: 80.66 TWh) 29.6% 17.6% 13.6% 12.0% Discuss: Primary Application Areas for Process Integration?

13. T. Gundersen E&M 13 Process, Energy and System Energy & Environment Main Focus in TEP 4215: Efficient Use of Energy Saving Energy means Saving the Environment in one or more Ways (CO 2, SO x, NO x, Particulates) Process Integration provides Methods and Tools to improve Heat Recovery and Heat Integration The Result is reduced Energy Consumption With the current Energy Mix this also means reduced Emissions from Fossil Fuels The Systems Approach in Process Integration can be used also to reduce Waste and other Impacts from the Process Industries

14. T. Gundersen E&M 14 Process, Energy and System Energy & Environment What we’ve done in TEP 4215 Process Integration Heat Recovery between Hot and Cold Streams to reduce Energy Consumption in the form of Hot and Cold Utilities Heat Integration of Distillation Columns and Evaporators with the “Background Process” Use of Heat Pumps to “lift” Thermal Energy (Heat) from below to above the Pinch by using Mechanical Energy (Power or Electricity) Combined Heat and Power (Cogeneration) by using Backpressure Turbines and deliver Heat to the Process or District Heating System while producing Power/Electricity Process Modifications to improve Scope for Heat Recovery guided by the “Plus/Minus” Principle

15. T. Gundersen E&M 15 Process, Energy and System Energy & Environment Tools developed in Process Integration The Composite Curves  Provides Insight and a Graphical Way to establish Energy Targets  Suggests Process Modifications (+/− Principle) The Grand Composite Curve  Based on the Heat Cascade − a Transshipment Model  Optimal Mix of Utilities (including Production)  Possible Integration of Reactors  Integration of Distillation Columns and Evaporators  Potential for and Correct Use of Heat Pumps  Combined Heat and Power Considerations

16. T. Gundersen E&M 16 Process, Energy and System Energy & Environment A brief Discussion about Efficiencies Energy vs. Exergy Efficiency  Exergy is defined as the Ability to produce Work  Exergy screens Energy Types w.r.t. Quality  Exergy does not reflect Cost − or better: The Cost of various Energy Forms does not reflect the 2 nd Law Component vs. System Efficiency  “Local” vs. “Global” Considerations  Importing Electricity may improve Plant Efficiency and Emission Figures (inside Battery Limits)  With Process Integration, Systems Thinking and utilizing Synergies, Component Efficiencies become less Important and System Efficiency improves

17. T. Gundersen E&M 17 Process, Energy and System Energy & Environment Basic Principle for Combined Cycle Plant

18. T. Gundersen E&M 18 Process, Energy and System Energy & Environment Combined Cycle Power Plant Power Production onlyHeat & Power Production Ref.: Olav Bolland

19. T. Gundersen E&M 19 Process, Energy and System Energy & Environment Some Efficiency Calculations Exergy Content of Heat Q at Temperature T  E x = Q  (1 − T 0 /T)  T 0 is “ambient” temperature (25°C or ≅ 298 K) Exergy Content of Fuel  Includes Chemical Exergy − Difficult !!  Often taken to be the Low Heating Value (LHV)  More pragmatic: Pure (100%) Exergy Exergy Content of Power & Electricity  This is Pure Exergy !! Calculations on the Blackboard The Heat Pump “Congregation”  Produce Electricity, “take back” the Heat later !!

20. T. Gundersen E&M 20 Process, Energy and System Energy & Environment Indicators for CO 2 Emissions Material Production  tons of CO 2 /tons of Product Energy Production  tons of CO 2 /MWh Electricity Consider 3 Cases of Power Production  Natural Gas (assume pure CH 4 ) based Combined Cycle Power Plant with an Efficiency of 60%  Same as above but Cogeneration of Heat and Power with a Total Efficiency of 90%  State of the art Coal (assume C/H=1) based Power Plant with an Efficiency of 40% Calculations on the Blackboard Fuel Switching can be Powerful