Effective Reduction of Industrial GHG Emissions via Energy ... · Effective Reduction of Industrial...

Effective Reduction of Industrial GHG Emissions via Energy Integration and

Biomass Utilization

Eva Lovelady and Mahmoud El-Halwagi

Process Integration and Systems Optimization GroupDepartment of Chemical Engineering

Texas A & M University

1Process Integration and Systems Optimization Group

1

Motivation• Substantial quantities from energy utilities• GHGs + Precursors for Ozone

Gaseous Wastes

pulpwashwater

RawMaterials Products

este

r

screeningBrown Stock Washing

chipspulp water

O D D DE E

Fuel/Energy Byproducts

Dig

e

conc

entra

tor Recovery Boiler

cond.cond.

weak SBL

FlueGas

Material Utilities Wastes

ESP

Multiple Effect Evaporators

white liquor

black liquor

weak

dissolving weak white liquor

dust recycle

smeltsalt

cakewashwater

wash

fluegaslime mud

white liquorclarifier

dregslime kilntank

mud washer

mud filter dregs

washer& filter

washwater


2

slaker green liquor clarifiercausticizer grits

Primary Responsibilities/Goals of Process EngineersGoals of Process EngineersFaster, Better, Cheaper, Safer, & Greener

Profitability Improvementld h

Specific Objectives:

Yield EnhancementResource (mass and energy) ConservationPollution Prevention/Waste Minimization

Safety ImprovementSafety ImprovementQuality Enhancement

How?


3

Traditional Approaches to Process Development and ImprovementProcess Development and Improvement

Brainstorming among experienced engineers

Heuristics based on experience-based rules

Evolutionary techniques: Copy (or adapt) the lastdesign we or someone else designed


4

Weaknesses/Limitations of Traditional Approaches Traditional Approaches

Time and money intensive

Cannot enumerate the infinite alternatives

Not guaranteed to come close to optimum

Does not shed light on global insights & keycharacteristics of the process

Limited range of applicabilityLimited range of applicability

Severely limits groundbreaking and novel ideas


5

Solution?

Systematic, fundamental, & generally applicable techniques

Process Synthesis Process Analysisy y

Process Integration


6

Process Synthesis Process Analysis

Process Integration

Process Synthesis

ProcessProcess Inputs(Given)

Process Outputs(Given)

ProcessStructure

& Parameters(Given) (Given)(Unknown)


7

Process Synthesis Process Analysis

Process Integration

Process Analysis/Simulationy

Process Inputs(Gi )

Process Outputs(U k )

ProcessStructure

& Parameters(Given) (Unknown)& Parameters(Given)


8

Process Integration =Process Integration

gProcess Synthesis + Process Analysis + Process Optimization

Global InsightsGlobal Insights,Overall Interactions,Performance Targets,

Major Structural

ProcessSynthesis

ProcessAnalysis

Decisions

Input/Output Relations,Performance vs. Designand Operating Conditions

Process Optimization: Selection of the best solution fromamong the set of candidate solutions. Optimization derives the


9

g piteration between synthesis and analysis to an optimal closure.

Why Integration?y g

Mass Integration

Energy Integration

A need exists for an integration framework:

•Guide/assist process synthesis

•Conserve process resources


10

MSA’s (Lean Streams In)S1L1?

S2L2?

SjLj?

SNSLNS?

Massy1

t

y2t

R1, G1, y1s

R2, G2, y2s

x1s x2

sj

xjs xNS

t

Waste (Rich)

Waste (Rich)

ExchangeNetwork

yit

yNRt

Ri, Gi, yis

RNR, GNR, yNRs

( )Streams(Sources) In

(Rich) Streams(Sources) O tNetwork

t t t t

In Out

x1t x2

t xjt xNS

t

MSA’s (Lean Streams Out)


11Schematic Representation of the MEN Synthesis Problem

MassExchanged

Excess Capacityof Process MSAs

Mass ExchangePinch Point

RichComposite

LeanComposite

MaximumIntegrated

MassStreamStreamMinimum

LoadFor

MassExchange

sx tx 11

1 ε−−=

byx

yForExternal

MSAs


12

x1

sx2

x1

tx2

11

1 m

22

22 ε−−=

mbyx

El-Halwagi and Manousiouthakis, 1989

DESIGN CHALLENGES

• Which mass-exchange technologies should be used?

• Which MSAs should be used?

• What is optimum flowrate of each MSA?p

• Where should each MSA be used (stream pairing)?

S t fi ti ?• System configuration?


13

What is Process Integration?

A holistic approach to process design, retrofitting,and operation, which emphasizes the unity of the process.

Involves:

1.) Task identification

2.) Targeting

3.) Generation of alternatives (Synthesis)

4 ) Selection of alternatives (Synthesis)4.) Selection of alternatives (Synthesis)

5.) Analysis of selected alternatives


14

Targeting

Identification of performance benchmarksfor the whole process AHEAD of detailed design

Specific Performance Targets:

Profitability improvement (maximization)

Yield enhancement (maximization)

Resource (mass & energy) conservation (minimization)

Pollution prevention/waste minimization (minimization)

Safety improvement (maximization)


15

y p ( )

Categories of Process Integration

Energy

Property

ProcessMass

Mass Integration

+Energy Integration Process Integration

+

Property Integration+


16

Property Integration

Research ThemeReduction of GHGs and ozone precursors from industrial sources via:

1. Energy integration

energy conservation, cost savings, NO & CO reductionNOx & CO2 reduction

2. Incorporation of biomass into utility systems (e.g., co-firing)

Carbon recycling during growth (photosynthesis)Reduction in GHG emissions

• In-plant pollution prevention not end-of-pipe pollution control• Environmental benefit + cost and energy savings: win-win


17

Problem StatementConsider a process with:• A set of specific heating and cooling demands• Steam demands for non-heating purposes such as tracing, blanketing, stripping, etc.

A i i f l i • A certain requirement of electric power• A header system with steam generated by process operations and external fuel• A set of fossil fuels and biomass streams that may be used as energy sources in the processThe objective is to develop a systematic and generally applicable approach to target j p y g y pp pp gprocess cogeneration that effectively uses process sources and external biomass and biowaste streams while satisfying the process heating and non-heating steam demands, and to determine the GHG pricing options required to compete with fossil fuel cogeneration or electricity bought from external sources.

Product & Byproduct

F lR M t i l

Water

StPROCESS UTILITIES

Atmospheric Pollutants

Biomass

Power

FuelRaw Material

Waste Heat

Fuel

Power

Steam


18Waste Waste

Research Questions

• What are the optimum quantities and levels of heating and cooling utilities?

• At what pressure level should steam from the external fuel be generated?

• Is there a potential for power cogeneration? What is the • Is there a potential for power cogeneration? What is the cogeneration target?

• What is the optimum scheme for recycling/reusing process sources for energy purposes?sources for energy purposes?

• Can some of the combustible wastes be used instead of fresh fuel? To what extent? Where?

• What refrigeration technologies may be used (e.g., cooling towers, refrigeration cycles, absorptive refrigeration, etc.)?


19

Research Questions• What are the necessary process modifications that are required

to trade off the core-process units with the utility system?

• What cofiring ratio of biomass to fossil fuel should be used for • What cofiring ratio of biomass to fossil fuel should be used for external fuel steam generation?

• What is the benchmark for maximum cogeneration potential by utilization of biomass and biowaste streams and minimum usage utilization of biomass and biowaste streams and minimum usage of external thermal utilities?

• What is the benchmark for minimum emission of GHGs and ozone precursors (on a lifecycle basis) for the scenarios of using ozone precursors (on a lifecycle basis) for the scenarios of using current technologies, new technologies, and incorporating biomass into the utility system?

• What are the sound policy recommendations that will enable • What are the sound policy recommendations that will enable market penetration of biomass-based cogeneration in the process industries? What are the corresponding technical and economic issues? What are the net reductions in ozone precursors and GHG emissions?


20

Project Objectives• Develop a systematic and generally applicable approach to the

optimization of design and operation process combined heat and power as well as integration with the core processing units Cost reduction + energy savings + reduction in GHGs and ozone precursorsenergy savings + reduction in GHGs and ozone precursors

• Determine the various feasible pathways and technologies for utilizing biomass in processing facilities, specially for cogeneration

• Provide an economic, energy and environmental evaluation of the prospects for biomass utilization in processing facilities

• Examine how potential GHG emission pricing alternatives might i fl th l ti ffi i i f lt ti t h l i d th influence the relative efficiencies of alternative technologies and other strategies as well as the power generation market penetration of biomass.

• Examine the sensitivity of the findings in the face of a wide spectrum of possibilities for variables pertaining to processing characteristics, possibilities for variables pertaining to processing characteristics, biomass availability, attributes and pricing, relative costs of power and heat, GHG trading markets and pricing, evolution of new environmental regulations, and technological advancements


21

Approach

• Process Cogeneration: energy integration, d i ti d ti i ti design, operation, and optimization

• Biomass Utilization for Energy: integration, design, operation, and optimization

• Techno-Economic-Environmental Analysis d P li R d tiand Policy Recommendations


22

Energy Integration and Combined Heat and PowerCombined Heat and Power

SCOPESCOPE• Energy conservation• Heat exchange networks• Heat exchange networks• Process cogeneration

O ti i ti f t d tilit t• Optimization of steam and utility systems


23

MotivationProduct & Byproduct

FuelRaw Material

Water

SteamPROCESS UTILITIES

Gaseous Wastes (e.g., GHGs)

Water

Power

FuelRaw Material

Waste Heat

Fuel

Power

Steam

Waste Effluent & Gaseous Waste Wastewater & Solid Waste

Optimize– Process production and operation– Fuel– Power– Steam (purchased & generated)– Water


24

– Waste Gas (e.g., GHG) Discharge

Heat Integration

Cold Streams In

HeatE hHot HotExchangeNetwork

(HEN)

HotStreams

In

HotStreams

Out

Cold Streams Out•Which heating/cooling utilities should be employed ?•Which heating/cooling utilities should be employed ?•What is the optimal heat load to be removed/added by each utility?•How should the hot and cold streams be matched (i.e., stream pairings)?•What is the optimal system configuration (e.g., how should the heat


25

exchangers be arranged? Is there any stream splitting and mixing ?)

HeatExchanged

Thermal Pinch Diagram

Exchanged

MinimumHeating Utility

Heat ExchangePinch Point

HotCold MaximumI t t dComposite

StreamComposite

StreamMinimum

IntegratedHeat

Exchange

TCoolingUtility


26minTTt Δ−=

Grand Composite Curves

• Site-wide heat integration• Targeting and selection of each utilityTargeting and selection of each utility

Linnhoff B Townsend D W Boland D Hewitt G F Thomas B E A Guy A R and


27

Linnhoff, B., Townsend, D. W., Boland, D., Hewitt, G. F., Thomas, B. E. A., Guy, A. R., and Marsland, R. H. (1982). "User Guide on Process Integration for the Efficient Use of Energy," Warwickshire, UK.

Cogeneration in a Chemical Plant

• In the chemical Plant’s utility system, ti b i l t d bcogeneration can be implemented by:

– Cogenerating Power with heatIntegrating heat/power requirements within the – Integrating heat/power requirements within the thermodynamic cycle


28

Cogenerating Power with Heat

• Power cogeneration with heat is utilized when expanding steam from a pressure level to anothersteam from a pressure level to another.


29

Steam Headers and CHPGenerated Steam + Steam from Higher Pressure Level

Steam from aFuel Fired Generated Steam + Steam from Higher Pressure Level

High Pressure Steam Header

Fuel-FiredBoiler and/orWaste Heat Boiler(after material recycle)

High Pressure Steam HeaderProcess Heat Demand,Process Cooling Demand,Process Non-heating/coolingDemand, vent, losses Back-pressure

(Topping)MultistageExtraction Condensing

BFW Let-DownValve

Turbine Turbine Turbine

Low Pressure Steam Header

Steam to lower Pressure Level

To Reheating, BFW,C d

Process Heat Demand,Process Cooling Demand,Process Non-heating/cooling


30

To Reheating, BFW,or other Destination

CondenserProcess Non-heating/coolingDemand, vent, losses

Managing Steam Headers


31

Cogeneration Power Pinch Diagram

Harell D., and El-Halwagi M., “Design Techniques and Software Development for Cogeneration Targeting


32with Mass and Energy Integration,” AIChE Spring Meeting, New Orleans, March 2003

Biomass in Utility Systemsy y• Cost reduction,

efficiency i t d

GaseousWasteimprovement, and

NOx/CO2 reduction through combined heat and power (CHP) i

VHP

Waste

(CHP) in process industries

• Capturing power generation potential HP

Process Steam Demands

through pressure reduction in steam systems: “cogeneration”

MPProcess Steam Demands

• Utilization of biomass or biowaste for partial/total

LPFossilFuels

Process Steam Demands

Process Steam D d

Biomass


33

p /cogeneration Demands

Conclusions

• Systematic and generally-applicable procedures for the design and operation of optimum cogeneration and biomass

tili ti d ti i GHG d (+ t utilization reduction in GHGs and ozone precursors (+ cost and energy savings)

• An integrated approach for analysis of technical, economic and environmental aspects of cogeneration and biomass utilization.

• In-process modifications leading to cost savings, energy conservation, and reduction in GHGs and ozone precursors.

• Strong interaction with industry• Strong interaction with industry.• Dissemination via publications, workshops, monograph, and

software.• Insights on short- and long-term solutions and

d l krecommendations to policymakers.


34

QUESTIONS?QUESTIONS?


35

Process Integration & Systems Optimization

El Halwagi Research GroupEl-Halwagi Research GroupDepartment of Chemical Engineering

Texas A&M University

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