modeling as a tool - belia
TRANSCRIPT
Modeling as a tool for energy
analysis and optimization
E. BELIA, PRIMODAL US INC.
2014 Energy Workshop: “A Water and Wastewater Utility
Guide to More Sustainable Energy Management”
East Lansing, Michigan, October 16, 2014
2014 Energy Workshop: “A Water and Wastewater Utility Guide to More Sustainable Energy Management”
East Lansing, Michigan, October 16, 2014
Overview
• Modeling basics
• Overview of tools
• Examples:
– DO vs. ammonia control for energy reduction
– N removal vs. increased gas production
2014 Energy Workshop: “A Water and Wastewater Utility Guide to More Sustainable Energy Management”
East Lansing, Michigan, October 16, 2014
2014 Energy Workshop: “A Water and Wastewater Utility Guide to More Sustainable Energy Management”
East Lansing, Michigan, October 16, 2014
What Is Modelling?
• What is a model? – System representation that can predict some system behavior
• Essential elements of models – Series of process equations
– Parameter values (allow the model to be calibrated)
– Initial (starting point) & boundary conditions
– Dynamics (time-varying performance vs. steady-state)
2014 Energy Workshop: “A Water and Wastewater Utility Guide to More Sustainable Energy Management”
East Lansing, Michigan, October 16, 2014
SIMBA#
2014 Energy Workshop: “A Water and Wastewater Utility Guide to More Sustainable Energy Management”
East Lansing, Michigan, October 16, 2014
Models for Energy Optimization
• Impact of dynamics
• Energy tariff implications
• Control design and testing
• Balancing multiple objectives
• Energy balance
• Equipment selection (e.g. blowers)
• ……..
2014 Energy Workshop: “A Water and Wastewater Utility Guide to More Sustainable Energy Management”
East Lansing, Michigan, October 16, 2014
Example 1:
DO vs. Ammonia/DO cascade
feedback control
2014 Energy Workshop: “A Water and Wastewater Utility Guide to More Sustainable Energy Management”
East Lansing, Michigan, October 16, 2014
Objectives
• Evaluate two control strategies
• Balance energy usage and cost
• Meet effluent ammonia consent
• Variable tariff
• Fixed air distribution
2014 Energy Workshop: “A Water and Wastewater Utility Guide to More Sustainable Energy Management”
East Lansing, Michigan, October 16, 2014
Plant Layout
2014 Energy Workshop: “A Water and Wastewater Utility Guide to More Sustainable Energy Management”
East Lansing, Michigan, October 16, 2014
M
DO
Controller
Manipulated
variable Pressurized air
Reference variable (setpoint)
Measured variable (Actual value)
O2
NH4 controller
DO f(NH4)
NH4
Aeration Control Strategies
Mixed
Liquor
Primary
Influent
2014 Energy Workshop: “A Water and Wastewater Utility Guide to More Sustainable Energy Management”
East Lansing, Michigan, October 16, 2014
Influent COD Load and
Electricity Tariff
$0.00
$0.02
$0.04
$0.06
$0.08
$0.10
$0.12
$0.14
0
20
40
60
80
100
120
140
160
12:00 AM 4:48 AM 9:36 AM 2:24 PM 7:12 PM 12:00 AM
Ele
ctri
city
co
st
CO
D lo
ad (
t/d
)
Time
COD load
Electricity tariff
2014 Energy Workshop: “A Water and Wastewater Utility Guide to More Sustainable Energy Management”
East Lansing, Michigan, October 16, 2014
Cost Comparison of the two
Control Strategies
$0
$1,000
$2,000
$3,000
$4,000
$5,000
$6,000
$7,000
$8,000
$9,000
$10,000
0
500,000
1,000,000
1,500,000
2,000,000
2,500,000
3,000,000
3,500,000
4,000,000
4,500,000
12:00 AM 4:48 AM 9:36 AM 2:24 PM 7:12 PM 12:00 AM 4:48 AM
Aera
tio
n C
ost
($)
Air
Flo
w (
Nm
3/d
)
Time (d)
Airflow - DO setpoint Airflow - Ammonia/DO Aeration Cost - DO setpoint Aeration Cost - Ammonia/DO
2014 Energy Workshop: “A Water and Wastewater Utility Guide to More Sustainable Energy Management”
East Lansing, Michigan, October 16, 2014
Example 2: Balancing COD
Flow
2014 Energy Workshop: “A Water and Wastewater Utility Guide to More Sustainable Energy Management”
East Lansing, Michigan, October 16, 2014
Objectives
• Existing small primary tank (30% TSS
removal)
• Site constraints
• CEPT evaluation
• Balancing:
– Aeration cost
– Digester gas production
– Nitrogen removal
2014 Energy Workshop: “A Water and Wastewater Utility Guide to More Sustainable Energy Management”
East Lansing, Michigan, October 16, 2014
Plant Layout
2014 Energy Workshop: “A Water and Wastewater Utility Guide to More Sustainable Energy Management”
East Lansing, Michigan, October 16, 2014
Low Primary Tank Removal
2014 Energy Workshop: “A Water and Wastewater Utility Guide to More Sustainable Energy Management”
East Lansing, Michigan, October 16, 2014
Simulating Chemically
Enhanced Primary Treatment
2014 Energy Workshop: “A Water and Wastewater Utility Guide to More Sustainable Energy Management”
East Lansing, Michigan, October 16, 2014
Scenario Comparison
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
1 2
% T
SS
rem
oval
Primary Tank Removal
Curren CEPT
0
5,000
10,000
15,000
20,000
25,000
30,000
Current CEPT
Air
flo
w (
Nm
3/d
)
Blower
0
2
4
6
8
10
12
14
16
0
50
100
150
200
250
1 2 3 4
Efflu
ent N
Ox-N
(m
g/L
)
Bio
gas (
m3/d
)
Biogas vs. Nitrate
Digester Gas
Effluent NOx-N
Current CEPT
2014 Energy Workshop: “A Water and Wastewater Utility Guide to More Sustainable Energy Management”
East Lansing, Michigan, October 16, 2014
Summary of Model Potential
• Wastewater “flight” simulator
• Dynamic interactions between influent,
control, energy and cost
• Balancing costs and risks
2014 Energy Workshop: “A Water and Wastewater Utility Guide to More Sustainable Energy Management”
East Lansing, Michigan, October 16, 2014
Presenter contact information
Evangelina Belia Ph.D., ing.
Primodal Inc.
US & Canada
www.primodal.com