IDRIST – Temporal pinch-point
analysis for energy demand
reduction in batch production
Thorsten Spillmann
Content
• Introduction to IDRIST project
• Importance of pinch-methodology for energy
demand reduction
• Challenges of thermal integration in batch processes
• Summary of approach taken
• Outlook
2 IDRIST – Thorsten Spillmann 1 – workshop 08/01/2016
IDRIST Project Phases Industrial Demand Reduction through Innovative Storage
Technologies
1. Market Potential Assessment
1. Identify industry needs and market potential
2. Investigation of Integrated PCM thermal storage systems
1. Identify and characterise candidate PCMs
2. Design laboratory tests and simulation
3. Experimental evaluation & model validation
4. System modelling for industrial applications
3. Investigation of Thermo-chemical heat storage and
transformation
1. Short list salt-refrigerant working pairs using ideal
thermodynamics
4. Whole systems modelling
1. Business models, techno-economic assessments
2. Whole system performance modelling
Poster presented at 2015 UKES Conference
online at: http://i-stute.org/
IDRIST – Thorsten Spillmann 2 – workshop 08/01/2016
Pinch methodology for energy
demand reduction (1) • Pinch Analysis is a discipline of Process Integration, which emphasises on the “efficient
use of energy and reducing environmental effects“ (IEA).
• Developed for heat recovery in continuous production processes, but also used in other
areas (e.g. waste water minimisation, hydrogen distribution in oil refineries)
• Central Aspect is the identification of the point of smallest driving force for network
integration
• Pinch Concept: Establishment of performance targets before design
IDRIST – Thorsten Spillmann 3
Data Collection
Performance Targeting
Network Design
Network Optimisation
• 4-Phase Approach:
– workshop 08/01/2016
Data Collection
Performance Targeting
Network Design
Network Optimisation
Pinch methodology for energy
demand reduction (2)
IDRIST – Thorsten Spillmann 4
Data Collection
• 4-Phase Approach:
Stream ID Ts(°C) Tt(°C) T*s(°C) T*
t(°C) MCp(kW/°C) ΔQ(kW) ΔTmin(°C)
Reactor Outlet H1 270 160 280 170 18 1980 20
Product H2 220 60 230 70 22 3520
Feed C1 50 210 40 200 20 3200
Recycle C2 160 210 150 200 50 2500
Block diagram
Stream data
• Necessary stream data from energy audit:
• Mass flow rate
• Specific heat capacity
• Supply & Target temperatures
• Decision if heat integration of certain units is not desired
• Costly piping
• Start and stop times
• Heat of vaporisation
• Safety, product purity • operability
– workshop 08/01/2016
Data Collection
Performance Targeting
Network Design
Network Optimisation
Pinch methodology for energy
demand reduction (3)
IDRIST – Thorsten Spillmann 5
Performance Targeting
• 4-Phase Approach:
Stream ID Ts(°C) Tt(°C) T*s(°C) T*
t(°C) MCp(kW/°C) ΔQ(kW) ΔTmin(°C)
Reactor Outlet H1 270 160 250 140 18 1980 20
Product H2 220 60 210 40 22 3520
Feed C1 50 210 70 230 20 3200
Recycle C2 160 210 180 230 50 2500
Stream data
0
50
100
150
200
250
300
0 2000 4000 6000
Tem
pera
ture
(°C
)
Heat Duty (kW)
hot streams
0
50
100
150
200
250
0 5000 10000
Heat Duty (kW)
cold streams
0
50
100
150
200
250
300
0 2000 4000 6000 8000
Tem
pera
ture
(°C
)
Heat Duty (kW)
Composite Streams
Hot Streams
ColdStreams
ΔTmin(°C)
Qc
Qh
0
50
100
150
200
250
300
0 1000 2000
Tem
pera
ture
(°C
)
Heat Duty (kW)
Grand Composite Curve
Qh
Qc
– workshop 08/01/2016
Data Collection
Performance Targeting
Network Design
Network Optimisation
Pinch methodology for energy
demand reduction (3)
IDRIST – Thorsten Spillmann 5
Performance Targeting
• 4-Phase Approach:
+720
-520
-1200
+400
+180
+220
260˚C
220˚C
210˚C
170˚C
150˚C
60˚C
50˚C
1000kW Qh
1720kW
1200kW
0kW
400kW
580kW
800kW Qc
• Streams are grouped together into
subnetworks based on their temperatures
• A minimum ΔTmin for heat exchange is defined
that represents the physical constraint to heat
transfer and is related to heat exchanger
surface area and costs.
• The pinch point represents the location in the
network, where the driving force for heat
transfer is minimal 0
50
100
150
200
250
300
0 1000 2000
Tem
pera
ture
(°C
)
Heat Duty (kW)
Grand Composite Curve
Qh
Qc
– workshop 08/01/2016
Data Collection
Performance Targeting
Network Design
Network Optimisation
Pinch methodology for energy
demand reduction (3)
IDRIST – Thorsten Spillmann 5
Performance Targeting
• 4-Phase Approach:
+720
-520
-1200
+400
+180
+220
260˚C
220˚C
210˚C
170˚C
150˚C
60˚C
50˚C
1000kW
1720kW
1200kW
0kW
400kW
580kW
800kW
• The pinch divides the network into a high
temperature region, that only requires hot utility
supply, and a low temperature region, that only
requires cold utility.
• Heat transfer between the two regions results in
increased utility demands.
• This means that subnetworks for the two regions
can be designed independently from one another
• Pockets of the Grand Composite Curve represent
internal heat transfer between subnetworks
– workshop 08/01/2016
Qh
Qc
AP
BP
Z
X
Y
+ (X + Z)
+ (Y + Z)
Data Collection
Performance Targeting
Network Design
Network Optimisation
Pinch methodology for energy
demand reduction (4)
IDRIST – Thorsten Spillmann 6
• 4-Phase Approach:
+720
-520
-1200
+400
+180
+220
260˚C
220˚C
210˚C
170˚C
150˚C
60˚C
50˚C
1000kW
1720kW
1200kW
0kW
400kW
580kW
800kW
Network Design
H1
160˚C 270˚C
H2
60˚C 220˚C
C1
50˚C 210˚C
C2
210˚C
160˚C
180˚C
1
1
2
2
3
3
H 178˚C
190˚C
4
4 C
C
80˚C
1000kW 620kW 880kW
2500kW
440kW
360kW
1000kW
– workshop 08/01/2016
Qh
Qc
AP
BP
Data Collection
Performance Targeting
Network Design
Network Optimisation
Pinch methodology for energy
demand reduction (5)
IDRIST – Thorsten Spillmann 7
• 4-Phase Approach:
+720
-520
-1200
+400
+180
+220
260˚C
220˚C
210˚C
170˚C
150˚C
60˚C
50˚C
1000kW
1720kW
1200kW
0kW
400kW
580kW
800kW
H1
160˚C 270˚C
H2
60˚C 220˚C
C1
50˚C 210˚C
C2
210˚C
160˚C
180˚C
1
1
3
3
H 4
4 C
C
80˚C
1000kW
1620kW
880kW
2500kW
440kW
360kW
Network Optimisation
– workshop 08/01/2016
Qh
Qc
AP
BP
Batch 1
Thermal integration in batch
processes
IDRIST – Thorsten Spillmann 8
• Process Integration becomes more complex with the time-dependence of process
streams, i.e. heat transfer possibilities are now constrained not only by temperature, but
also by time
• Heat exchange can occur direct, when processes occur at the same time, or indirect
when heat is exchanged with a storage medium to be used at a later point in time
• Limited implementation due to lack of established methods and design tools.
Approaches suggested in literature differ according to simplifying assumption made and
degree of complexity
• Two types of thermal integration: within batches, between batches
task
1
task
2 task
3
Batch 2
task
1
task
2 task
3
TES
TES
– workshop 08/01/2016
Approach taken (1)
IDRIST – Thorsten Spillmann 9
• Division of time horizon into intervals
with pseudo-continuous streams
• Composition of interval specific heat
cascades identifying utility demand
reduction through direct heat
integration (within individual intervals).
• Composition of modified heat cascades
identifying further reductions in utility
requirements due to indirect heat
integration (between intervals).
• Initial Heat Exchange Network Design
based on Pinch Design Method
Name Tsupply Ttarget MCp tstart tstop ΔTmin
C1 80 140 8 0 0.5 10
H1 170 60 4 0.25 1 10
C2 20 135 10 0.5 0.7 10
H2 150 30 3 0.3 0.8 10
Literature Example: Chaturvedi (2014)
– workshop 08/01/2016
IDRIST – Thorsten Spillmann 10
Divide streams into time slices
Use conventional pinch methodology (PTA) to calculate utility targets
Direct Heat Transfer
Modify GCC to determine thermal energy available for integration with subsequent
intervals
Repeat Integration Procedure for subsequent interval with
shifted temperatures including pseudo hot streams
Indirect Heat Transfer
Approach taken (2)
0
50
100
150
200
250
Ho
t U
tili
ty D
em
an
d (
kW
h)
Results for 3 example cases
direct
within batch
between batches
heat transfer
= heat available from subnetworks
for integration with subsequent intervals
– workshop 08/01/2016
Grand Composite Curves
Outlook • Complete Computerised Initial Network Design Method
• Adapt targeting routine to represent different thermal store/ heat exchanger designs
• Utilise routine on further example cases from literature and industry
IDRIST – Thorsten Spillmann 11 – workshop 08/01/2016
THANK YOU!
18 – workshop 07/10/2015 IDRIST – Thorsten Spillmann