ENERGY EFFICIENCY BOILER IN
INDUSTRY – CASE STUDY FOR
INDUSTRY
DR. NGUYEN XUAN QUANG
SCHOOL OF HEAT ENGINEERING AND REFRIGERATION
HANOI UNIVERSITY OF SCIENCE AND TECHNOLOGY
CONTENT
 Introduction of UNIDO project “Promotion of energy efficient
industrial boiler adoption and operating practices in Vietnam”
 Activities have been done to support to project
 Boiler assessment activities.
 Case study 1
 Case study 2
 Case study 3
 Case study 4
 Lessons and experiences in boiler operation process
INTRODUCTION OF UNIDO BOILER PROJECT

Project title: “Promotion of energy efficient industrial boiler adoption and operating
practices in Vietnam” (in short “EEBP”)

Duration: 4 years (starting from November 2015 to October 2019)

Executing agency: Ministry of Industry & Trade (MOIT)

Implementing agency: United Nations Industrial Development Organization (UNIDO)

Other project partners: STAMEQ-MOST, MONRE, MOLISA, ECCs, Boiler Manufacturers
and Vietinbank

Target beneficiaries:
•
Industrial enterprises (end-users) in subsectors: pulp & paper, textile & garment,
food processing, chemical & fertilizer, wood-processing, etc.
•
Boiler manufacturers/providers
PROJECT BUDGET
•
Total project Budget: US$ 12,053,000, of which:
 GEF grant: US$ 1,771,000
 UNIDO inputs: US$ 110,000 (cash and in-kind)
 Total committed co-financing by Vietnamese partners is US$ 10,282,000, of
which:
• MOIT: US$ 1,725,000 (cash and in-kind)
• ECCs: US$ 535,000 (in-kind)
• Boiler Manufacturers: US$ 500,000 (in-kind)
• Vietinbank: US$ 7,412,000 (loan program)
4
4
Project Objectives
Project Objectives: to reduce energy consumption and GHG emissions
through promotion of EE industrial boilers
Indicators
Measurable energy reductions by industry
Calculated GHG emissions reductions
Annual target
10-year target
1,955,304 GJ
19,553,045 GJ
183,736 ton CO2
1,837,355 ton CO2
25,000,000
19,553,045
20,000,000
Energy saving (GJ)
15,000,000
GHG reductions (ton CO2)
10,000,000
5,000,000
0
1,837,3551,955,304
183,736
Annual target
10-year target
5
5
5
Project components
1. About the IEE project
Information
exchange
Component 1: Policy and regulatory framework
to support the boiler standardization system.
Component 2: Awareness, training and capacity
building for government agencies, boiler owners,
operators, and manufacturers, and other
stakeholders.
Component 3: Financing and implementation of
energy efficient boiler adoption projects and
manufacturing.
The major themes of EEBP project are
the improvement of policy & regulatory
framework, the capacity building and EE
boiler projects implementation.
Awareness
WSs
National standards
on boiler technical
requirements
& MEP
Boiler
operation
certification
& Inventory
Policy and
regulatory
framework
Guidelines
on funds,
loans &
tax
schemes
Training on
EE
bankable
project
evaluation
National
communica
tion
strategy
Awareness
program
EEBP
Financial
support
Implementation
of DEMOs &
Replication
DEMO and
replication
Projects
Implementatio
n
Boiler
efficiency
evaluation
training
Boiler
Operating
practices
training
Training
programs
Mobilizatio
n of
available
financial
source
Boiler
Manufacturing
Practices &
business &
Marketing
training
ACTIVITIES HAVE BEEN DONE TO SUPPORT PROJECT
•
Support to evaluate the software used for thermal calculation of boiler
design
•
Support to prepare training materials for the project training activites
•
Support to evaluate the Instruments used for boiler assessment
•
Conduct the boiler efficiency measurement training for boiler user and
boiler evaluation experts with and without international experts.
•
Assessing 29 boilers to evaluate boiler efficiency as well as giving
energy conservation opportunities of boiler in 24 factories in Vietnam
BOILER ASSESSMENTS ACTIVITIES
•
Assessment and proposing energy saving solutions for boiler/steam supply system
performed by experts training in line with UNIDO program are with the following contents:
•
Measuring and assessing boiler efficiency at the plant with standard devices/instrument
equipped by UNIDO project;
•
Measurement are carried out in an automatic recording over a long period of a few days to a
week, so that the actual boiler working status can be assessed based in load variation. The
results is more reliable;
•
The final evaluation report and the proposal of energy saving solutions for the boiler and steam
supplying system were sent to the plant at the same time with in-depth consultation on how to
carry out;
•
The plants get 3 months to decide and implement the proper energy saving solutions in line with
the actual situation of the plant;
•
The experts return to the plant to assess the efficiency of implementing energy saving solutions.
BOILER ASSESSMENTS ACTIVITIES
The number of boiler by capacity classification
STT
1.
Parameters
Total evaluated plants
Unit
Plant
Chart - Boilers classification
by capacity
Number
Boilers with
capacity less than
10tph
24
17%
2.
Total assessed boilers
2.1 Boilers with capacity less than 10tph
2.2
Boilers with a capacity range of 10 tph
to 25 tph
2.3 Boilers with capacity exceeding 25tph
Boiler
29
Boiler
13
Boiler
11
Boiler
5
45%
38%
Boilers with a
capacity range of
10 tph to 25 tph
Boilers with
capacity exceeding
25tph
BOILER ASSESSMENT ACTIVITIES
The number of boilers by fuel classification
STT
1.
Parameters
Total assessed boilers
Unit
Number
Boiler
29
1.1 Boilers using coal as a fuel
Boiler
16
Boilers using biomass as a
fuel
Boiler
5
1.2
1.3 Multi-fueled Boilers
Boiler
Chart - Boilers classification
by fuel
7%
7%
Mutil-fueled boilers
55%
17%
Boiler
2
1.5 Boilers using LPG as a fuel
Boiler
2
Boilers using biomass as a
fuel
14%
4
1.4 Boilers using oil as a fuel
Boilers using coal as a fuel
Boilers using oil as a fuel
Boilers using LPG as a fuel
BOILER ASSESSMENT ACTIVITIES
Table 3. List of proposed main solutions
No
1
2
3
4
5
6
7
8
9
10
11
Solution title
Adjusting combustion mode
Controlling blowdown regime
Adjusting oxygen concentration of flue gas
Increasing temperature of feed water
Improving insulation of furnace shells
Repairing economizer
Repairing air preheater
Repairing steam leakage
Replacing by a new boiler in accordance with load and operation mode
Utilizing flue gas temperature
Combining the combustion additive and coal
BOILER ASSESSMENT ACTIVITIES
Chart - The number of proposed and performed main solutions
20
20
18
16
14
12
10
8
6
4
2
0
18
Proposed Main solution
15
Performed Main solution
8
4
4
6
5
2
4
4
3
3
2
4
6
3
2
1
1
BOILER ASSESSMENT ACTIVITIES
Results of implemented solutions
No
Fuel type
Unit
1
Coal
tons/year
2
Oil
1000
littre/year
3
Biomass
tons/year
4
LPG
tons/year
Saving
CO2 reduction
No
Fuel type
19.589
1
Coal
115
2
Oil
3
Biomass
1.275
4
LPG
1.292
7.628
435
(tons CO2/year)
49.952
368
BOILER ASSESSMENT ACTIVITIES
GHG emission reduction by the implemented solutions
STT
Implemented solutions
1
2
3
Adjusting combustion mode
Controlling blowdown regime
Adjusting oxygen concentration of flue gas
4
5
6
Increasing temperature of feed water
7
8
9
10
11
Improving insulation of furnace shells
Repairing economizer
Repairing air preheater
Repairing steam leakage
Replacing by a new boiler in accordance with load and operation mode
Utilizing flue gas temperature
Combining the combustion additive and coal
CO2 Reduction
(tCO2)
19.733
6.328
9.999
1.932
2.560
6.765
4.363
373
370
412
6.765
CASE STUDY 1
HANOI DYEING JOINT STOCK COMPANY
•
Name of company: Hanoi Dyeing Joint Stock Company- Hung Yen branch
•
Address: Pho Noi B industrial Area, Lieu Xa commune, Yen My district, Hung Yen
province
•
Main field: Textile products
•
Annual operation days: 250 days
•
Designed boiler capacity: 6tph
•
Fuel: Coal
•
Boiler efficiency before implementing energy saving solutions: 70.92%
CASE STUDY 1
Background
•
Boiler capacity: 6 tph
•
This boiler system was equipped a system of
condensate water recovery and an economizer
improving the boiler efficiency;
•
The oxygen concentration of the flue gas was
16.46%. This very high value caused heat loss due
to flue gas to high;
•
The difference of flue gas temperature before and
after the economizer is very low. This shows that
the economizer was operating inefficiently;
•
Boilers operated at 30% - 40% of the designed
capacity.
CASE STUDY 1
•
%
The following are some figures of measuring result
Figure - Oxygen concentration in flue gas
20.00
Figure - Flue gas temperature before/after
economizer
18.00
16.00
14.00
12.00
10.00
1
18
35
52
69
86
103
120
137
154
171
188
205
222
239
256
273
290
307
324
341
358
375
392
409
426
443
460
8.00
Time
Time
CASE STUDY 1
Energy saving solution
•
Adjusting oxygen concentration of flue gas
 The plant carried out this solution (the oxygen concentration of flue gas
deceased from 16,68% down 14,17%) in April 2018.
•
Repairing the economizer
 The plant inspected and cleaned the economizer in May 2018 and the
temperature of the flue gas after the economizer is 92oC.
•
Replacing by a new boiler in accordance with load and operation mode
 The plant replaced by a new boiler in September 2019. Its efficiency
currently is 89% higher than the old one (18.08%).
CASE STUDY 1
Achieved results after implementing boiler efficiency improvement
No
(1)
Items
(2)
1.
Designed boiler capacity (ton/hr.)
2.
Boiler efficiency (%)
3.
Average steam output (ton/hr.)
4.
Steam output (ton/yr.)
5.
Specific energy consumption (kg
coal/ton of steam)
6.
Total energy consumption (ton coal/yr.)
7.
CO2 emission (ton/yr.)
Situation before
implementing
(3)
Results after
implementing
(4)
Saving*
(4) – (3)
6
6
-
70.92
77.46
6.54
2.23
2.23
-
10,704
10,704
-
122
112
-10
1,308
1,067
-241
3,336
2,721
-615
* Note: This result was excluded the solution of "Replace by a new boiler"
CASE STUDY 2
Traphaco high technology jsc
General information
•
Name of company: : Traphaco High Technology JSC
•
Address: Tan Quang commune, Van Lam district, Hung Yen province.
•
Main field: Medicine
•
Annual operation days: 350 days
•
Designed boiler capacity: 6 tph
•
Fuel: 4b dust coal
•
Boiler efficiency before implementing energy saving solutions: 53.91%
CASE STUDY 2
Background
•
Boiler capacity: 6 tph
•
This boiler system has been equipped an air preheater.
However, the air preheater is only used for drying residue
from production process to use as a additional fuel and at
the measuring time, it was not operating due to no demand;
•
The oxygen concentration of the flue gas was 15.1%. This
very high coefficient caused heat loss due to flue gas to
high;
•
Flue gas temperature is 184oC (high), while the air preheater
was not operating;
•
Unburned carbon in ash is very high (37%);
•
Boiler surface temperature is in a range from 50oC - 80oC. In
addition, the result was taken at the ambient temperature of
25oC.
•
%
Figure - Oxygen concentration in flue
gas
oC
16.5
16
15
14
13
12.5
Time
11:30:00
11:36:00
11:42:00
11:48:00
11:54:00
12:00:00
12:06:00
12:14:00
12:20:00
13:06:00
13:12:00
13:18:00
13:24:00
13:30:00
13:36:00
13:42:00
13:48:00
13:54:00
14:00:00
14:06:00
14:16:00
14:44:00
14:50:00
14:56:00
15:02:00
15:08:00
15:14:00
15:20:00
17
11:30:00
11:54:00
12:20:00
13:24:00
13:48:00
14:16:00
15:02:00
15:26:00
15:50:00
16:14:00
16:38:00
18:02:00
18:26:00
19:58:00
20:22:00
22:12:00
22:36:00
23:00:00
23:50:00
00:32:00
01:12:00
02:14:00
02:40:00
03:04:00
03:28:00
03:52:00
04:20:00
09:48:00
CASE STUDY 2
Measuring results
Figure - Flue gas temperature
190
185
15.5
180
14.5
175
13.5
170
165
Time
CASE STUDY 2
Energy saving solution
•
Adjusting oxygen concentration of flue gas
 The plant carried out this solution (the oxygen concentration of flue
gas deceased from 15.1% down 11.8%) in December 2019.
•
Adjusting combustion mode
 The plant implemented this solution (proportion of unburned carbon
in ash decreased from 36.88% down 29.3%) in December 2019.
•
Repairing the insulation of furnace shell.
•
Utilizing the flue gas heat.
CASE STUDY 2
Achieved results after implementing boiler efficiency improvement
No
(1)
Items
(2)
1.
Designed boiler capacity (ton/hr.)
2.
Boiler efficiency (%)
3.
Average steam output (ton/hr.)
4.
Steam output (ton/yr.)
5.
6.
7.
Specific energy consumption (kg
coal/ton of steam)
Total energy consumption (ton
coal/yr.)
CO2 emission (ton/yr.)
Situation before
implementing
(3)
Results after
implementing
(4)
Saving*
(4) – (3)
4
4
-
53.91
60.1
6.19
1.31
1.31
-
10,121
10,121
-
176
151
-25
1,785
1,527
-257
4,511
3,895
-656
CASE STUDY 3
General information
•
Name of Company : Vinachem – DAP 2 JSC
•
Address : Tang Loong industrial area, Bao Thang district, Lao Cai
province
•
Major product: DAP fertilizer
•
Annual operation days: 262 days
•
Designed capacity: 65 tph
•
Fuel: Vang Danh 5b dust coal
•
Boiler efficiency before implementing energy saving solutions : 89.28%
CASE STUDY 3
Background
•
Boiler capacity: 65 tph
•
This boiler system has been fully equipped with devices that absorb extra heat
after combustion chambers such as an economizer, an air preheater. Also,
deaerator and measurement sensors of temperature and oxygen is equipped to
monitor the boiler operation;
•
The oxygen concentration of the flue gas is 3.5%;
•
The temperature of flue gas is 140oC;
•
The blowdown water conductivity is too low to operate the boiler at 38 bar;
•
Ratio of unburned carbon in fly ash is 19.2% and it is pretty high;
•
The surface temperature of steam pipeline system is 184oC and the measuring
time was carried out at the highest ambient temperature of 20oC. So the heat
loss was very high;
•
The leakage of the steam supply system is very much;
•
The plant releases always excess steam into the environment.
%
8
Figure - Oxygen Concentration in flue gas
7
6
3
2
1
0
Time
oC
5
300
4
250
15:46:15
19:54:15
23:08:15
4:51:15
8:39:15
12:01:15
15:15:15
18:31:15
21:45:15
0:59:15
4:27:15
7:41:15
10:55:15
14:09:15
17:23:15
20:37:15
23:51:15
3:05:15
6:19:15
10:26:15
15:46:15
18:21:15
21:18:15
23:37:15
4:25:15
6:44:15
9:37:15
12:04:15
14:23:15
16:44:15
19:03:15
21:22:15
23:41:15
2:00:15
4:33:15
6:52:15
9:11:15
11:30:15
13:49:15
16:08:15
18:27:15
20:46:15
23:05:15
1:24:15
3:43:15
6:02:15
8:21:15
11:39:15
CASE STUDY 3
Measuring results
Figure - Temperature of flue gas
400
350
200
150
100
Time
Flue gas
temperature
after furnace
(oC)
Flue gas
temperature
after
economizer
(oC)
Flue gas
temperature
after air
preheater
(oC)
CASE STUDY 3
•
Actual situation of steam system
Broken insulation
Steam leakage
Excess steam
released from
SA workshop
CASE STUDY 3
Energy saving solution
•
Improving insulation of steam supply system
 The plant has carried out in April 2019.
•
Repairing steam leakage
 The plant has done in April 2019.
•
Combining the combustion additive and coal
 The plant has done in May 2019 and combustion additive AX 8040.
•
Improving insulation of the furnace shell
•
Adjusting blowdown regime
•
Recovering the steam emitted from SA workshop.
CASE STUDY 3
Achieved results after implementing boiler efficiency improvement
No
(1)
Items
(2)
1.
Designed boiler capacity (ton/hr.)
2.
Situation before
implementing
(3)
Results after
implementing
(4)
Improvement*
(4) – (3)
65
65
-
Boiler efficiency (%)
89.28
90.50
1.22
3.
Average steam output (ton/hr.)
56.85
56.85
-
4.
Steam output (ton/yr.)
357,442
357,442
-
5.
Specific energy consumption
(kg coal/ton of steam)
186
172
-14
6.
Total energy consumption
(ton coal/yr.)
66,657
61,590
-5,067
7.
CO2 emission (ton/yr.)
169,975
157,055
-12,920
CASE STUDY 4
General information
•
Name of Company: Hai Phong Hapaco Paper JSC
•
Address: Tien Nong village, Dai Ban commune, An Duong district, Hai
Phong province
•
Major product: Paper
•
Annual operation day: 320 days
•
Boiler designed capacity: 15 tph
•
Fuel: 4-5b dust coal
•
Boiler efficiency before implementing energy saving solutions: 46.72%
CASE STUDY 4
Background
•
Boiler capacity: 15 tph
•
The boiler system has been equipped an economizer
improving boiler efficiency. However, during survey process,
the experts found that it was broken without repairing a long
time ago;
•
The oxygen concentration of the flue gas is 14.5%. This value
is too high to make heat loss due to flue gas so much;
•
Blowdown ratio of 6.47% is too high to make heat loss more;
•
The flue gas temperature of 245oC is very high, while the
economizer was broken without repairing a long time ago;
•
The steam leakage of the steam supply system is high;
16.00
Figure - Oxygen concentration in flue gas
15.50
15.00
14.50
14.00
13.50
13.00
Time
oC
12.50
220
12.00
210
12:01:00
12:32:00
13:09:00
13:41:00
14:07:00
14:36:00
15:05:00
15:32:00
16:38:00
17:30:00
18:10:00
18:51:00
19:28:00
20:05:00
20:44:00
16:22:00
00:58:00
06:17:00
10:13:00
10:40:00
11:15:00
11:43:00
17:12:00
18:40:00
04:00:00
%
12:01:00
12:31:00
13:07:00
13:36:00
14:02:00
14:27:00
14:56:00
15:23:00
16:06:00
16:58:00
17:49:00
18:30:00
19:02:00
19:49:00
20:14:00
14:45:00
16:28:00
01:47:00
06:31:00
10:16:00
10:44:00
11:16:00
11:43:00
17:11:00
18:38:00
03:57:00
14:43:00
CASE STUDY 4
Measuring results
Figure - Temperature of flue gas
270
260
250
240
230
Time
CASE STUDY 4
Energy saving solution
•
Adjusting oxygen concentration of flue gas
 The plant has decreased oxygen concentration of flue gas from 14.5%
down 12.3% in December 2019.
•
Repairing economizer
 The plant has repaired economizer and the flue gas temperature
decreased from 254oC down 195oC in December 2019.
•
Repairing steam leakage.
•
Controlling blowdown regime.
CASE STUDY 4
Achieved results after implementing boiler efficiency improvement
No
(1)
Items
(2)
1.
Designed boiler capacity (ton/hr.)
2.
Boiler efficiency (%)
3.
Average steam output (ton/hr.)
4.
Steam output (ton/yr.)
5.
Specific energy consumption
(kg coal/ton of steam)
6.
7.
Situation before
implementing
(3)
Results after
implementing
(4)
Improvement*
(4) – (3)
15
15
-
46.72
56.02
9.3
5.03
5.03
-
38,593
38,593
-
156
125
-31
Total energy consumption
(ton coal/yr.)
6,010
4,811
-1,199
CO2 emission (ton/yr.)
15,326
12,269
3,056
LESSONS AND EXPERIENCES IN BOILER
OPERATION PROCESS
•
For boilers with the 25tph less capacity, staff often operate based on experience leading large heat loss due to
blowdown and flue gas;
•
Chain grate boilers don’t often control heat loss due to unburned carbon (q4) properly, so this loss are usually quite
large, and especially it is for boilers with operation mode at great fluctuated loads.
•
Most boilers haven’t been equipped with sensors of temperature or oxygen concentration; thus it is impossible to
control the performance of economizer and air preheater causing the high heat losses due to flue gas.
•
In the boiler operation, operators don’t consider recording and synthesizing major operating parameters such as
hourly feed water, coal consumption, pressure, flue gas temperature, oxygen concentration of flue gas and
blowdown/feed water conductivity. The record will be very useful for operators to form the process of operating
boiler according to the load demand.
•
Commonly, plants only consider supplying enough steam for the production process, so they don’t focus on how to
operate boiler efficiently and economically.
•
It is limited knowledge of the boiler in general, as well as the implementation of energy saving solutions in practice
in particular, there are so many energy saving opportunities in boiler and the steam system.
•
In many cases, boiler equipped have capacity much higher than the actual demand, boilers operating in low load
leading to inefficient operation and difficult for adjusting oxigent in flue gas.
THANK YOU VERY MUCH!