Special Lecture on Energy & Environment Process Process - - PowerPoint PPT Presentation

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Special Lecture on Energy & Environment Process Process - - PowerPoint PPT Presentation

Aug 23, 2022 335 likes •552 views

Special Lecture on Energy & Environment Process Process Process, Energy and System Integration Energy Environment Clean Process Technology (Ch. 28 in R. Smith) Classes of Waste (Process & Utility) Environmental Impacts from

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SLIDE 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 Environment Energy

Process Integration

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SLIDE 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:

u Choose Reactions Paths that avoid harmful Chemicals

being produced as byproducts

u Keep harmful Chemicals “inside the loop” by

combining producing and consuming Reactions

u Closing Processes as in Pulp & Paper

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SLIDE 3
  • T. Gundersen

E&M 03

Process, Energy and System Energy & Environment

Sources of Waste from the Process Industry

  • Types of Process Waste:

u Waste Byproducts, Purge Streams, etc.

  • Sources of Process Waste:

u Reactors (byproducts, used catalysts, etc.) u Separation & Recycle Systems (inadequate

recovery and recycle of valuable materials)

u Process Operations (start-up, shutdown, product

changeover, equipment cleaning, etc.)

R S H U R + S : Process Waste H + U : Utility Waste

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SLIDE 4
  • T. Gundersen

E&M 04

Process, Energy and System Energy & Environment

Sources of Waste from the Process Industry

  • Types of Utility Waste:

u Gaseous Combustion Products (CO2, SOx, NOx, Particles) u Aqueous Waste from BFW (Boiler FeedWater) Treatment u Waste from Water Systems

  • Sources of Utility Waste:

u Hot Utilities (incl. Cogeneration) u Cold Utilities and Water Systems

R S H U R + S : Process Waste H + U : Utility Waste

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SLIDE 5
  • T. Gundersen

E&M 05

Process, Energy and System Energy & Environment

Sources of Waste from the Process Industry

  • Our Focus in these Lectures:

u Environmental Impacts from Energy Consumption

  • Remember to take a Systems Approach:

u Local Emissions vs. Global Emissions u Producing or importing Electricity?

R S H U R + S : Process Waste H + U : Utility Waste

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SLIDE 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 CO2
  • NOx and SOx
  • CH4 , NH3 and other volatile compounds
  • Particles (“Particulates”)
  • VOC (Volatile Organic Compounds)
  • Heat (or Cooling)
  • Wastewater
  • Using scarce Freshwater Resources
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SLIDE 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)

u Photochemical Reactions u VOCs + NOx + O2 è O3 (Ozone) + Other

Photochemical Pollutants (Aldehydes, Peroxynitrates, etc.)

  • Acid Rain

u Natural Precipitation is slightly acidic with pH around 5-6

§ Carbonic acid from dissolved CO2 § Sulfuric acids from natural emissions of SOx and H2S

u Human Activity can reduce pH to 2-4

§ Mainly caused by emissions of SOx § This is a primarily a local environmental problem § Can be a regional problem (from UK to Norway)

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SLIDE 8
  • T. Gundersen

E&M 08

Process, Energy and System Energy & Environment

Environmental Design for Atmospheric Emissions

(Continued)

  • Ozone Layer Destruction

u Lower Levels of the Atmosphere: Ozone is harmful! u Upper Levels: Ozone essential; it absorbs ultraviolet light! u Destruction is due to Oxides of Nitrogen and Halocarbons

  • The Greenhouse Effect

u CO2 , CH4 and H2O 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

u This Balance can be disturbed è Global Warming

§ Burning Fossil Fuels (increased emission of CO2) § Large Scale harvest of Forests (reduced absorption of CO2)

  • The largest Volume of Atmospheric Emissions

from Process Plants is due to Combustion

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SLIDE 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

u Process Integration increases Energy Efficiency and

results in Energy (in various forms) not being used

u Investment in Equipment may cause use of Fossil Fuel

based Energy elsewhere (considering LCA)

  • More comprehensive List of Actions

u Use less Energy (vs. “Standard” of Living) u Increase Energy Efficiency u Increase Process Efficiency u Switch between Fossil Fuels u Switch from Fossil Fuels to Renewables

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SLIDE 10
  • T. Gundersen

E&M 10

Process, Energy and System Energy & Environment

“Energi21” − National Strategy for R&D, Demonstration & Commercialization − Energy in the 21st Century

  • The Vision of Energi21

u 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

u Efficient Use of Energy (Industry/Transport/Buildings) u Climate-friendly Power u CO2-neutral Heating u An Energy System to meet the Needs of the Future u Desirable Framework Conditions for R&D

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SLIDE 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)

Industry & Mining Transportation Other Sectors

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) = 1012

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SLIDE 12
  • T. Gundersen

E&M 12

Process, Energy and System Energy & Environment

Aluminum Chemical Pulp & Paper Petrochemical Food Industry Iron & Steel Minerals Wood Ware Mining Others

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?

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SLIDE 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
  • ne or more Ways (CO2, SOx, NOx, 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

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SLIDE 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

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SLIDE 15
  • T. Gundersen

E&M 15

Process, Energy and System Energy & Environment

Tools developed in Process Integration

  • The Composite Curves

u Provides Insight and a Graphical Way to establish

Energy Targets

u Suggests Process Modifications (+/− Principle)

  • The Grand Composite Curve

u Based on the Heat Cascade − a Transshipment Model u Optimal Mix of Utilities (including Production) u Possible Integration of Reactors u Integration of Distillation Columns and Evaporators u Potential for and Correct Use of Heat Pumps u Combined Heat and Power Considerations

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SLIDE 16
  • T. Gundersen

E&M 16

Process, Energy and System Energy & Environment

A brief Discussion about Efficiencies

  • Energy vs. Exergy Efficiency

u Exergy is defined as the Ability to produce Work u Exergy screens Energy Types w.r.t. Quality u Exergy does not reflect Cost − or better: The Cost

  • f various Energy Forms does not reflect the 2nd Law
  • Component vs. System Efficiency

u “Local” vs. “Global” Considerations u Importing Electricity may improve Plant Efficiency

and Emission Figures (inside Battery Limits)

u With Process Integration, Systems Thinking and

utilizing Synergies, Component Efficiencies become less Important and System Efficiency improves

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SLIDE 17
  • T. Gundersen

E&M 17

Process, Energy and System Energy & Environment

Basic Principle for Combined Cycle Plant

Ref.: Olav Bolland

100% 40% 30% 10% 20%

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SLIDE 18
  • T. Gundersen

E&M 18

Process, Energy and System Energy & Environment

Combined Cycle Power Plant

% 5 . 48 100 5 . 48 % 5 . 89 100 41 5 . 48 = = = = + = + = E P E Q P η η % 57 100 57 = = = E P η

Power Production only Heat & Power Production

Ref.: Olav Bolland

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SLIDE 19
  • T. Gundersen

E&M 19

Process, Energy and System Energy & Environment

Some Efficiency Calculations

  • Exergy Content of Heat Q at Temperature T

u Ex = Q Ÿ (1 − T0/T) u T0 is “ambient” temperature (25°C or ≅ 298 K)

  • Exergy Content of Fuel

u Includes Chemical Exergy − Difficult !! u Often taken to be the Low Heating Value (LHV) u More pragmatic: Pure (100%) Exergy

  • Exergy Content of Power & Electricity

u This is Pure Exergy !!

  • Calculations on the Blackboard
  • The Heat Pump “Congregation”

u Produce Electricity, “take back” the Heat later !!

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SLIDE 20
  • T. Gundersen

E&M 20

Process, Energy and System Energy & Environment

Indicators for CO2 Emissions

  • Material Production

u tons of CO2/tons of Product

  • Energy Production

u tons of CO2/MWh Electricity

  • Consider 3 Cases of Power Production

u Natural Gas (assume pure CH4) based Combined

Cycle Power Plant with an Efficiency of 60%

u Same as above but Cogeneration of Heat and

Power with a Total Efficiency of 90%

u 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