International Journal of Greenhouse Gas Control 110 (2021) 103423
Contents lists available at ScienceDirect
International Journal of Greenhouse Gas Control
journal homepage: www.elsevier.com/locate/ijggc
The experience in the research and design of a 2 million tons/year flue gas
CO2 capture project for coal-fired power plants
Shijian Lu a, b, d, *, Mengxiang Fang c, Qingfang Li b, Hongfu Chen b, Fu Chen a, Wentan Sun d,
Hui Wang b, Haiyan Liu b, Jian Zhang b, Xinjun Zhang b, Haili Liu b
a
Low Carbon Energy Institute, China University of Mining and Technology, 1University Road, Xuzhou, Jiangsu 221116, PR China
Sinopec Petroleum Engineering Corporation, 49 Jinan Road, Dongying, Shandong 257026, PR China
College of Energy Engineering, Zhejiang University, 866 yuhangtang Road, Xihu District, Hangzhou, Zhejiang 310058, PR China
d
School of Politics and Public Administration, Xinjiang University, No.666 Shengli Road, Xinjiang Uygur Autonomous Region, Urumqi 830046, PR China
b
c
A R T I C L E I N F O
A B S T R A C T
Keywords:
Flue gas
CO2 capture
Chemical absorption
Economic analysis
Research and design experience
The world’s largest 2 million tons/year CO2 capture project from flue gas of coal power plants for EOR at Shengli
oilfield of China was introduced. The blend amine absorbent performance, chemical absorption process, energysaving method, and the layout area of engineering were interpreted. The health, safety, and environmental affect
was analyzed and economic analysis was also carried out. The conclusion showed that the project has technical
and economic feasibility. The study showed that the total energy consumption per unit product is 121.4 kg
(standard coal equivalent (SCE))/tCO2, and the comprehensive regeneration energy consumption of the project is
less than 2.2GJ/tCO2. The total investment of the project is 1329.4 million CNY; the after-tax internal rate of
return reaches 8% when the ex-factory price of CO2 is 301.84 CNY /t(excluding tax).
1. Introduction
In 2019, China’s carbon emissions exceeded 11.3 billion tons, more
than twice that of the United States and three times greater than that of
the European Union, accounting for about 30 percent of the global
emission. The amount of carbon emission reduction required to achieve
carbon neutrality is much higher than that of the other economies
(United Nations Environment Programme, 2020). At the Paris Climate
Conference in November 2015, President Xi Jinping promised that CO2
emissions of China would peak in the year 2030, and CO2 emissions per
unit of gross domestic product (GDP) would be decreased by 60–65%
from 2005 levels (UNEP 2020a, 2020b, 2020c). On September 22, 2020,
President Xi Jinping said at the UN General Assembly that China will
increase its intended nationally determined contribution (INDC), adopt
more forceful policies and measures, and strive to peak its CO2 emissions
by 2030 and achieve carbon neutrality by 2060 (Zhang and Zhang,
2020). CO2 emission reduction has become one substantial strategy for
the sustainable development of China. The State Council and various
ministries and commissions have issued policies and targets to conduct
emission reduction.
According to the prediction of Jiang Kejun based on the 1.5 ℃
scenario (Jiang, 2019), compared with 2020, the average annual CO2
emissions will be reduced by nearly 10 billion tons by 2050, through
measures including sharply reducing the use of traditional coal, greatly
developing clean energy such as nuclear power, solar power and wind
power, and accelerating the development of fossil fuel plus CCUS (CO2
Capture Utilization and Storage)technology. Among them, CCUS, which
has the potential to reduce the overall cost of emission reduction and
increase the flexibility to achieve greenhouse gas emission reduction
(IPCC Working Group 3 Meeting, 2005), has become one of the main
approaches to carbon emission reduction and the bottom line technol­
ogy to achieve carbon neutrality in 2060.
CCUS technology is the only one that can directly reduce the carbon
emission in crucial areas and reduce the existing CO2 concentration to
balance the inevitable carbon emission (IEA, 2020). According to IPCC’s
prediction based on various scenarios, if the CO2 emission reduction
cannot reach more than 41% before 2030, the CCUS technology will
become the main force to guarantee a 1.5 ℃ target (UNEP, 2020d). The
further analysis proposed by International Energy Agency shows that
under the sustainable development scenario, CCUS will account for
19.2% of the annual carbon emission reduction contribution and 15% of
the cumulative carbon emission reduction contribution by 2070 (UNEP,
* Corresponding author at: Low Carbon Energy Institute, China University of Mining and Technology, 1University Road, Xuzhou, Jiangsu 221116, PR China.
E-mail address: lushijian@cumt.edu.cn (S. Lu).
https://doi.org/10.1016/j.ijggc.2021.103423
Received 26 January 2021; Received in revised form 9 July 2021; Accepted 29 July 2021
Available online 19 August 2021
1750-5836/© 2021 Published by Elsevier Ltd.
S. Lu et al.
International Journal of Greenhouse Gas Control 110 (2021) 103423
2020e). At present, coal is the most important energy consumption in
China, and coal-fired power plants are the primary source of CO2
emissions (IPCC Working Group 3 Meeting, 2005). The CO2 capture and
use in oil displacement of coal-fired power plants and the underground
storage at the same time have noticeable ecological and environmental
benefits and can increase the output of crude oil and guarantee the
national energy supply.
As one important capture technology of post-combustion, chemical
absorption technology has been used in industry for many years in China
and around the world. Petra Nova Power Plant in the United States
elected and put into operation the world largest flue gas CO2 capture
project with an annual output of 1.4 million tons of CO2 in 2016. In
Saskatchewan, Canada, Boundary Dam Power Plant constructed and put
into operation the flue gas CO2 capture project with an annual output of
1 million tons of CO2 in 2015. In China, a 120000 t/a flue gas CO2
capture project at Huaneng Shanghai Shidongkou the second power
plant, and 100 t/d flue gas CO2 capture and oil displacement storage
project at Shengli Power Plant was built. Shaanxi Guohua Jinjie power
plant 150,000 tons/year of power plant flue gas CO2 capture and
sequestration project, the largest flue gas CO2 capture demonstration
project in China, is under construction. In summary, comprehensive
design experience, construction experience, and operation experience
for flue gas CO2 capture project have been formed in China.
Based on its characteristics, Sinopec has actively carried out carbon
emission reduction, CO2 capture, and recovery, and has already carried
out a series of CO2 flooding utilization and storage projects in Shengli
Oilfield, Zhongyuan Oilfield, Jiangsu Oilfield, and Northwest Oilfield,
etc., and achieved good results. With the support of China’s national
carbon-neutral vision, Sinopec plans to carry out 2 million tons/year
CO2 capture and EOR project. This paper introduced the system design
and feasibility study of the project.
Table 2
Flue gas composition of Unit 4 of Shengli power plant.
Mole fraction /(mol%)
31.999
64.065
44.011
—
18.015
—
6.68
26.8 mg/Nm3
12.47
0.56 mg/Nm3
9.43
42.3mg/Nm3
O2
SO2
CO2
The smoke concentration
H2O
NOX
31.999
64.065
44.011
—
18.015
—
6.65
24.3 mg/Nm3
11.73
0.67 mg/Nm3
9.42
42.3 mg/Nm3
Component
Molecular weight
Mole fraction /(mol%)
O2
SO2
CO2
The smoke concentration
H2O
NOX
31.999
64.065
44.011
—
18.015
—
5.56
24.6 mg/Nm3
12.54
0.96 mg/Nm3
14.3
44.5 mg/Nm3
2.1. Absorbent selection
This capture project adopts the chemical absorption method. The
reaction principle is as follows: organic amine-based absorbent absorbs
CO2 from flue gas at low temperature to form amino carbonate. Then,
amino carbonates decompose in the regeneration tower at high tem­
peratures. During the processes, CO2 is released, and the absorbent re­
absorbs CO2 after recovering heat and cooling. The absorbent is
composed of primary amine, secondary amine, tertiary amine and ste­
rically hindered amine, which has the characteristics of high absorption
rate and large absorption capacity.
When primary amine and secondary amine react with CO2, the total
reaction formula is as follows:
(1)
CO2 +2R1R2NH = R1R2NH2+ + R1R2NCOO-
When tertiary amine and sterically hindered amine react with CO2,
the total reaction formula is shown in formula 2:
(2)
CO2 + R1R2R3N + H2O↔R1R2R3NH+ + HCO3-
Compared with the MEA method at the same molarity, the active
amine absorption capacity and regenerative energy consumption were
Table 4
Design parameters of flue gas composition.
Table 1
Flue gas composition of Unit 3 of Shengli Power Plant.
Molecular weight
Mole fraction /(mol%)
CO2 of 10% volume fraction, SO2 of 35 mg/Nm3, NOX of 50 mg/Nm3
(wet basis). The design parameters of flue gas composition are shown in
Table 4.
There are many acid salts in the flue gas, and the condensate water is
acidic, which affects the material selection of pipeline, deep purification
tower, and absorption tower. The samples of condensed precipitation
water and washed water were analyzed. The ion and salt content shows
in Tables 5 and 6.
Sinopec has carried out a plan to capture and purify 2 million tons of
CO2 per year at the Shengli coal fired power plant in Shengli Oil Field.
These coal fired units include two subcritical power generation units of
300 MW (No. 3 and No. 4 unit) and one supercritical power generation
unit of 660 MW (No. 5).This project will serve as the largest postcombustion CO2 capture project, both domestic and overseas
currently. The project includes CO2 capture, CO2 recycling, and pipeline
transportation to the dense oil reservoir region of the Xianhe oil pro­
duction plant and Chunliang oil production plant by pipeline.
The CO2 capture facility is designed to handle the flue gas volume of
1.60 × 106 Nm3/h. The facility operates smoothly within the range of
50%–110% of production capacity, and the maximum load of the unit is
110% of the designed standard capacity. The continuous operation
hours of the facility is 8000 h.
The temperature of flue gas from power plant is about 52 ℃ and
pressure is about -0.2 kPag. The composition of flue gas after desulfur­
ization of units 3, 4, and 5 (dry base) was shown in the test results in
Tables 1– 3.
Due to the different coal in the process of power plant operation, the
concentration of CO2, SO2, and NOX in flue gas would vary with a
different situation, technology package of the project is designed with
O2
SO2
CO2
The smoke concentration
H2O
NOX
Molecular weight
Table 3
Flue gas composition of Unit 5 of Shengli power plant.
2. Project profile and primary feature
Component
Component
2
Component
Molecular weight
Mole fraction /(mol%)
CO2
O2
N2
44.011
31.999
28.014
10
7.28
69.27
SO2
SO3
Particle concentration
HCl
HF
H2O
NOX
64.065
80.064
/
36.461
20.006
18.015
/
35 mg/Nm3
/
5 mg/Nm3
/
/
13.45
50 mg/Nm3
S. Lu et al.
International Journal of Greenhouse Gas Control 110 (2021) 103423
the 150,000 t/ a flue gas CO2 capture project of Shaanxi Guohua Jinjie
power plant. The composition of absorbent is shown in Table 7.
The properties of the blend amine absorbent are shown in Tables 8,
9.
Table 5
Sample analysis of condensed precipitation water in flue gas.
serial
number
Measurements
Unit
Test
results
Basis of detection(Chinese
standard)
01
02
pH
lithium
2.25
0.04
GB/T 6920-1986
HJ 812-2016
03
sodium
04
ammonium
05
potassium
06
magnesium
07
calcium
08
fluoride
09
chloride
10
bromide
11
nitrate
12
Sulfuric acid
root
hydroxyl
/
mg/
L
mg/
L
mg/
L
mg/
L
mg/
L
mg/
L
mg/
L
mg/
L
mg/
L
mg/
L
mg/
L
mg/
L
mg/
L
mg/
L
13
14
15
Bicarbonate
root
Carbonic acid
root
2.2. Performance parameters
11.95
Under the premise of ensuring the quantity and quality of raw gas,
the device’s maximum designed load is 110% of the normal for stable
operation within the range of 50–110% of the rated production capacity.
The continuous operation time of the device is 8000 h per year.CO2 gas
production: 127,563 Nm3/h(Dry basis), The CO2 content is greater than
99.5%(Dry basis). CO2 Capture rate ≥ 80%. The technical parameters
are described in Table 10.
10.08
0.83
3.51
5.22
2.75
3. Process description
15.21
3.1. Process flow description
6.60
The process flow chart is shown in Fig. 1.The flue gas from the
outside enters into the tower from the lower part of the deep purification
tower and comes into contact with the aqueous solution spraying down
from the top of the tower to carry out mass transfer and heat transfer.
SO2 and part of NOx in the flue gas are washed away, and the temper­
ature drops to 40 ℃. The 40 ℃ flue gas, after removed SO2 flowed from
the top of the tower then pressurized into the absorber by a fan.
The washing water at the bottom of the deep purification tower is
pressurized by the deep purification tower pump and cooled below 40 ℃
by the washed water cooler, and then enters the deep purification tower
for circulating operation.
To ensure the desulfurization rate, a small amount of sodium hy­
droxide is added to the washing water. It is designed that the washed
water be discharged from the outlet of the deep purification tower pump
to the industrial wastewater treatment system.
After the pressure boost from the induced draft fan, the flue gas from
the separator enters the absorber from the lower part of the absorber and
then contacts with the lean solution from the upper part of the absorber
in reverse flow. 80% of the CO2 in the flue gas is absorbed by the solution
in the absorption section, and there is amine in the flue gas from the
absorption section to the washing section. Then the amine is washed
down through the washing section of the upper part of the absorber, and
the exhaust gas returns to the flue gas of the power plant.
Lean solution from the lean liquid cooler is filtered to remove im­
purities in the solution, and then it enters from the absorption section of
the absorber. From top to bottom, CO2 is absorbed from the flue gas. The
rich solution after CO2 absorption enters the rich liquid heat exchanger
after being pressurized by the rich liquid pump.
The upper part of the absorber is used as a washing section. The
washing water enters from the top of the absorber and comes into
contact with the rising flue gas to wash away the amine in the flue gas.
The washing water after washing amine flows into the washing liquid
storage tank from the lower part of the washing section of the absorber,
and then is pressurized by the exhaust gas washing pump, and then
enters the washing liquid cooler. It is cooled to 40 ℃ and then enters the
top of the absorber for washing. In such a circulating operation, the
washing water will overflow from the washing liquid storage tank to the
underground tank regularly as supplementary water. The washing water
8.83
388.94
0
0
Methods for Monitoring and
Analysis of Water and
Wastewater (Fourth Edition)
0
Table 6
Sampling analysis of flue gas washed water.
serial
number
Measurements
Unit
Test
results
Basis of detection (Chinese
standard)
01
03
pH
lithium
6.99
165.27
GB/T 6920-1986
HJ 812-2016
04
sodium
05
ammonium
06
potassium
07
magnesium
08
calcium
09
fluoride
10
chloride
11
bromide
12
nitrate
13
Sulfuric acid
root
hydroxyl
/
mg/
L
mg/
L
mg/
L
mg/
L
mg/
L
mg/
L
mg/
L
mg/
L
mg/
L
mg/
L
mg/
L
mg/
L
mg/
L
14
15
Bicarbonate
root
10.67
3.65
3.59
5.26
2.66
HJ 84-2016
16.39
6.57
13.02
397.37
0
10.4
Methods for Monitoring and
Analysis of Water and
Wastewater (Fourth Edition)
0
improved.The regeneration energy consumption of absorbent is less
than 2.9GJ/tCO2, and the absorption capacity is increased by more than
30% compared with MEA.The absorbent is reliable and safe,which has
been applied in several flue gas CO2 capture demonstration projects in
China, including the 40,000 t / a flue gas CO2 capture and oil
displacement storage project of Shengli Power Plant, the 100,000 t / a
flue gas CO2 capture project of Shanghai Shidongkou Power Plant, and
Table 7
Composition of absorbent.
3
Composition of absorbent
Mass fraction
Mixed amine
Antioxidants
Corrosion inhibitor
Water
20–30%
0.15–0.25%
0.08–0.15%
70–80%
S. Lu et al.
International Journal of Greenhouse Gas Control 110 (2021) 103423
Table 8
Physical and chemical properties of the absorbent.
Absorbent
concentration
Density /(g/cm3)(30110℃)
Viscosity(cp)/
(30-110℃)
Surface tension /(N/m)
(30-110℃)
Saturated vapor pressure
/(kPa)(30-110℃)
Specific heat capacity
/(kJ.kg-1.K-1)(40-110℃)
Heat of reaction /(kJ/
molCO2)(40-80℃)
3.3mol/L
5mol/L
0.9903~0.9376
0.9869~0.9304
1.87~0.39
3.02~0.49
0.0441~0.0320
0.0415~0.0301
3.97~134.92
3.76~129.20
3.82~3.95
3.64~3.81
78-97
78-97
Table 9
Key process parameters for industrial application of absorbent.
Absorbent
concentration
Absorption temperature
range /(℃)
Desorption temperature
range /(℃)
Desorption pressure range
/(kPag)
Absorption pressure range
/(kPag)
Amine recovery heating
temperature range /(℃)
3.3mol/L
30~50
100~120
30~50
100~120
Atmospheric pressure
~50
Atmospheric pressure
~50
120~155
5mol/L
Atmospheric pressure
~100
Atmospheric pressure
~100
The rich solution exchanged heat with the water vapor and CO2 from
the bottom of the desorber, and the CO2 was regenerated. Then it
entered the solution reboiler and further heated and desorbed out the
CO2. Lean solution flowed out from the bottom of the desorber. The
regenerated lean solution flowing from the bottom of the desorber
recovered heat through the lean and rich heat exchanger, which was
cooled to 40 ℃ by the lean solution cooler and then entered the
absorber, forming a continuous absorption and desorption cycle.
Desorber outflow of water vapor, CO2 after gas heat exchanger and
power plant phase II, phase III of condensation heat transfer, heat
transfer of gas by the gas cooler cooled to 50 ℃, gas water mixture to
enter the gas-liquid separator for gas-water separation, gas phase as a
product gas into subsequent compression drying process, the top liquid
back into regeneration.
After long-term use of the solution, the accumulated impurities can
be filtered through the filter, and the amine solution can also be distilled
through the amine recovery heater. Part of the lean liquid is continu­
ously added to the amine recovery heater by the lean solution pump, the
liquid level of the amine recovery heater is controlled, and the amine
and water are distilled to the regeneration tower through steam heating.
The final distillation impurities are discharged as a waste liquid.
After the capture process, the CO2 is separated by the separator to
remove the free water, which is carried with and then enters the
compressor. The CO2 at the compressor outlet is pressurized to a su­
percritical state with a pressure of 10.95 Mpa and a temperature of 50
℃. The compressor is pressurized with stage 11, and the stage 8 outlet
Table 10
Technical parameters.
1
2
Item
Unit
Quantity
Product gas
CO2≥99.5%(dry gas)
Operating
parameters
t/h
250
Circulating cooling water
(capture part)
Steam is used in reboiler
(0.3MPag)
Steam (1.0MPag) is used in
amine recovery heaters
Amine solvent supplement
Antioxidant
Corrosion inhibitor
Electricity (capture part)
t/ tCO2
ཞ52.8
t/ tCO2
≤1.37
t/ tCO2
≤0.08
kg/tCO2
kg/ tCO2
kg/ tCO2
kW/
tCO2
kg/ tCO2
kg/ tCO2
≤0.8
≤0.025
≤0.025
≤65
Desalted water (capture part)
Sodium hydroxide
120~155
ཞ48
ཞ0.596
can be replenished with water separated from the regenerating sepa­
rator by the rehydration pump or directly replenished with desalted
water.
The rich solution enters the rich solution heat exchanger after being
pressurized by the rich solution pump and conducts heat exchange with
the lean solution after being regenerated from the desorber. The tem­
perature rises after heat recovery, and the rich solution enters the
desorber from the upper part of the desorber.
Fig. 1. The process flow chart.
4
S. Lu et al.
International Journal of Greenhouse Gas Control 110 (2021) 103423
goes into the downstream dewatering unit.
The CO2 (8-stage exit) from the compression units enters the drying
tower for dehydration. The dehydration process uses high-temperature
composite silica gel as the adsorption carrier. After dehydration, the
water in the product gas drops to below 10 ppm (water dew point < -40
℃). Silica gel regeneration is equal pressure regeneration of pre-drying
of moisture; cold blowing in the cold blowing of moisture, CO2 after
regeneration, and cold blowing is returned to the dehydration system for
drying after cooling and separation. After supercharging and dewater­
ing, the gas enters the entrance of stage 9 of the compressor and con­
tinues to be supercharged and exported.
Table 12
Main operation parameters of deep purification tower.
Technological process
Process parameters
Height
Diameter
The temperature of flue gas entering the tower
Flue gas outlet temperature
Washing water into the tower temperature
Flow of washing water into the tower
Flue gas flow into the tower
25 m
20 m
50 ℃
40 ℃
40 ℃
4000 m3/h
71,544 kmol/h
Table 13
Main operation parameters of absorber.
3.2. Main operating conditions
Following the material balance by Aspen Plus and ProII process, the
absorbent performance verified by the pilot test, operation experience
from a CO2 capture project of 40,000 t/ a coal-fired power plant, the
design parameters and operation conditions of CO2 capture project are
obtained.
The main operating conditions of the capture system are shown in
Table 11, including flue gas inlet flow rate, CO2 content in inlet gas, inlet
temperature, solution circulation volume, absorption temperature,
desorption temperature, etc.
3.2.1. Deep purification tower
The main operation parameters of deep purification tower are shown
in Table 12, including flue gas inlet flow, inlet temperature and outlet
temperature, and washing water inlet flow and temperature.
Technological process
Process parameters
Height
Diameter
The temperature of flue gas entering the tower
Flue gas outlet temperature
Lean solution inlet temperature
Rich solution out tower temperature
Lean solution flow into the tower
Washing water into the tower temperature
Flow of washing water into the tower
Flue gas flow into the tower
64 m
20 m
45 ℃
48 ℃
40 ℃
56 ℃
5600 m3/h
40 ℃
2800 m3/h
66877 kmol/h
Table 14
Main operation parameters of the desorber.
3.2.2. Absorber
The main operating conditions of absorption tower are shown in
Table 13, including flue gas inlet flow, inlet temperature and outlet
temperature, lean liquid inlet flow and temperature, rich liquid outlet
temperature, solution circulation, washing water inlet temperature and
flow, etc.
Technological process
Process parameters
Height
Diameter
Flow of rich solution into the tower
Inlet temperature of rich solution
Lean solution outlet tower temperature
40 m
13 m
5600 m3/h
100 ℃
105 ℃
Table 15
Main operation parameters of amine recovery heater.
3.2.3. Desorber
Table 14 shows the main operating parameters of the desorber,
including the circulation amount of rich liquid into the tower, the
temperature of rich liquid into the tower and the temperature of lean
liquid out of the tower.
3.2.4. Amine recovery heater
Table 15 shows the main operating parameters of amine recovery
heater, including inlet temperature, inlet flow rate, outlet temperature
and amine recovery heater pressure.
Technological process
Process parameters
Amine recovery heater solution temperature
Amine recovery heater solution flow rate
Amine recovery heater gas temperature
Amine recovery heater pressure
61 ℃
230 m3/h
135 ℃
1.0 MPag
3.2.5. Regeneration gas-liquid separator
Table 16 shows the main operating parameters of amine recovery
heater, including regeneration gas flow and regeneration gas tempera­
ture after separation.
Table 11
Main operation parameters of the capture system.
3.3. Characteristics of energy saving process
5,600m3/h
CO2 content ཞ10.70
(v)%
CO2 content ཞ2.35
(v)%
CO2 content≥99.5
(v)%
/
The 2 million tons/year CO2 capture project adopts a new energysaving process of "interstage cooling + MVR heat pump + desorption
heat energy recovery",by applying which comprehensive regeneration
energy consumption is less than 2.2 GJ/tCO2. The energy consumption
level of regeneration reaches the leading level of flue gas CO2 capture
demonstration project. The energy saving process is shown in the brown
box in Fig. 1. The interstage cooling process reduces the temperature of
the semi-rich liquid and improves the CO2 absorption of the solution;
40℃
105℃
40ཞ50℃
/
/
/
Table 16
Main operation parameters of regeneration gas-liquid separator.
100℃
≤50℃
/
/
Technological process
Process
parameters
CO2 concentration
Flue gas flow into absorber (wet
base)
Flue gas out of absorber (wet base)
1559,089Nm3/h
System regenerated gas (dry base)
127,563Nm3/h
The amount of lean liquid into the
absorber
Lean absorbent of inlet absorber
Bottom temperature of the desorber
Flue gas temperature of inlet
absorber
Desorber temperature
Regeneration gases Cooling
temperature
3
1522474 Nm /h
5
Technological process
Process parameters
Regeneration gas flow out of system (dry basis)
Regeneration gas temperature
127563 Nm3/h
50 ℃
S. Lu et al.
International Journal of Greenhouse Gas Control 110 (2021) 103423
MVR heat pump process is used to recover flash steam heat of lean liquid
for heating and desorption of rich liquid, the mass of flash steam is
130120 kg/h, the latent heat value of flash recovery steam is 190 GJ/h;
The rengeneration gas exchanges heat with the condensate of the
generator set to recover the desorbed heat.
and take measures to reduce the escape and loss of amine solution as far
as possible.
The wastewater discharged by this unit mainly consists of a residual
solution of amine recovery heater, deep purification tower discharge,
and system cleaning water. The residual solution of the amine recovery
heater is recommended to be mixed with pulverized coal incineration
treatment. The deep purification tower discharge and system cleaning
water are discharged into the industrial wastewater treatment system,
and the discharge standard is according to the Comprehensive Sewage
Discharge Standard (Chinese standard: GB8978-2017 of China).
Low noise equipment should be selected as far as possible in the
design; installing silencers for noisy air vent systems; workers entering
noisy workplaces should wear more personal protective equipment.
4. Plane arrangement and consumption quota
According to the composition of the plant’s internal construction and
structures, the plant is divided into process unit area, transformer and
distribution area, steam supply unit area, circulating cooling water area,
and closed cooling tower group area, and the central control room is
arranged in the low-voltage distribution area. It covers a total area of
300 × 170 m.
The layout of main equipment is shown in Fig. 2.
The consumption quota of raw materials, public utilities, and main
consumption are shown in Table 17.
5.3. Safety and health
There are two kinds of poisonous and harmful substances in the
production process:
(1)Composite amine: organic amine, alkaline, is moderate harm to
chemical media, respiratory system, and certain harm to skin, so it’s
necessary to avoid inhalation. When preparing a composite amine
aqueous solution, it is necessary to wear protective gloves, goggles, and
masks. Meanwhile, an eye-washing device is set near the underground
tank. Once it splashes into the eyes or sticks to the skin, rinse it with
plenty of water immediately.
(2)CO2: Under normal conditions, CO2 is a colorless, odorless gas,
soluble in water, molecular formula CO2. The molecular weight is 44.01
and the solubility is 0.144 g/100g water (25 ℃). Carbon dioxide is
heavier than air, with a density of 1.977 g/L under standard conditions,
about 1.5 times that of air. Carbon dioxide is non-toxic, but it does not
provide breathing for animals. It is a choking gas. The air content is
usually 0.03% (volume); if the content reaches 10%, people will grad­
ually stop breathing and finally suffocated to death. It is necessary to set
up a carbon dioxide infrared acoustooptic alarm device in the field. Once
the concentration exceeds 1%, an alarm will be sent immediately. At the
same time, a wind vane is set at a high point, and a positive pressure
respirator and a mobile positive pressure fan are equipped in the control
room. Once the concentration exceeds the limit, operators are evacuated
to the upper wind direction. Emergency personnel is equipped with a
positive pressure respirator for emergency disposal, and a mobile fan is
used to purge CO2 from the factory.
5. Health, safety,and environmental protection
5.1. Major pollution sources and pollutant discharges
The device’s solution process is a closed-loop design, and all leaking
solutions and condensate are returned to the underground tank. Under
normal production conditions, waste liquid discharge is shown in
Table 18. The amine recovery heater’s residual solution is mainly the
amine absorbing agent’s degradation substance, such as 1- (2-hydrox­
yethyl) -imidazolinone, N- (2-hydroxyethyl) -ethylenediamine, N-phe­
nylethanolamine amino-acetic acid, and the amino compound formed
by amino-acetic acid and organic amine.
The noise of this unit mainly comes from the induced draft fan,
chemical process pump, and other power equipment. The noise sources
are shown in the table below (Table 19).
5.2. Wastes control measures
The exhaust gas discharged by this device mainly contains CO2, SO2,
and NOx. The emission standard shall be implemented following the
Comprehensive Emission Standard for Air Pollutants (Chinese standard:
GB16297-2017). As the exhaust gas will carry a small amount of amine
solution, after being discharged into the atmosphere, it will photolysis to
produce a trace of nitrosamines harmful substances, so it is necessary to
study and analyze the escape amount of absorbent in the design process,
Fig. 2. The equipment layout.
6
International Journal of Greenhouse Gas Control 110 (2021) 103423
S. Lu et al.
6. Energy consumption and net emission reduction analysis
Table 17
Raw materials, utilities, and major consumption quotas.
Serial
number
Description & specification
Unit
Quantity
Remark
1
Design scale: product gas
(dry gas)
Flue gas (dry gas)
Nm3/
h
Nm3/
h
t
127563
/
1387038
/
ཞ500
t
ཞ5
The original
driving 2500
m3 solution
t
t/a
ཞ5
ཞ2000
t/a
ཞ50
t/a
t/a
ཞ50
ཞ1192
t/h
ཞ13200
kW
ཞ16250
t/h
ཞ342.5
t/h
ཞ20
t/h
ཞ4000
t/h
ཞ12
t/tCO2
ཞ1.056
2
Chemicals
3
4
5
Chemicals
Utilities
Rate of
expenditure
Amine
solvent
Corrosion
inhibitor
Antioxidant
Amine
solvent
Corrosion
inhibitor
Antioxidant
Sodium
hydroxide
Circulating
water
(capture)
Electricity
(capture)
0.3MPag
steam
1.0MPa
steam is used
in amine
recovery
heaters
Industrial
water
(circulating
volume in
the system)
Desalted
water
Circulating
water
Electricity
(capture)
0.3 MPag
steam
1.0 MPa
steam (for
amine
recovery
heaters)
Amine
solvent
Corrosion
inhibitor
Antioxidant
Sodium
hydroxide
Industrial
water
Desalted
water
6
Floor space
/
6.1. Comprehensive energy consumption
For the energy and working medium of the project, the energy
conversion coefficient refers to the data published by the National Bu­
reau of Statistics of China. The energy discounting coefficient of the
energy produced by the project unit and the energy consumed by the
working medium for energy consumption shall be calculated based on
the actual input and output.
(1)Electric power
According to the General Rules for The Calculation of Comprehensive
Energy Consumption (China standard: GB/T 2589-2008), the value of
electricity is calculated by the coal consumption of thermal power
generation standard the current year. When the power standard coal
coefficient’s value is 0.1229 kg of SCE /kW•h, the equivalent value is
0.295 kg of SCE /(kW•h) of the power plant’s generation standard coal
consumption in 2019.
(2)Steam
The standard enthalpy of saturated steam was used to calculate the
index of steam deflection.
(3)Desalted water
The typical coal coefficient of desalination water is 0.4857 kg of SCE
/t.
(4)Fresh water
The standard coal coefficient of freshwater is 0.0857 kg of SCE /t.
Table 20 shows utility consumption in capture system,Table 21
shows utility consumption in compression and drying part,and the
utility consumption is converted into energy consumption value ac­
cording to the standard.
The total energy consumption per unit product, which contains
capture, compression, and drying, is 121.4 kg of SCE/tCO2 (Tables 22
and 23).
Annual
replenishment
runs
1.0 MPag steam
for amine
recovery
heater; 0.3 MPa
steam for
reboiler
Open cold
water tower
about 2%
evaporation
rate, and
floating rate
6.2. Calculation of net emission reduction
The total energy consumption per unit product is 121.4 kg of SCE
/tCO2. Since the collection scale of this project is 2 million tons/year, the
annual comprehensive energy consumption of this project is 24.3 ×
104tce(tons of standard coal equivalent). Also, because a total of 2.6 ton
CO2 is produced by 1ton standard coal, and 631,300 tons of CO2 is
emitted annually, the actual annual emission reduction is 1,368,700
tons of CO2.
kW•h/
tCO2
t/tCO2
ཞ65
ཞ1.37
Used in reboiler
t/tCO2
ཞ0.08
/
kg/
tCO2
kg/
tCO2
kg/
tCO2
kg/
tCO2
t/tCO2
≤1.0
/
7. Economical analysis
≤0.025
/
7.1. Total investment costs
≤0.025
/
≤0.596
/
/
84 m3 washed
water per hour
(flue gas
cooling
precipitation
water)
Preparation of
fresh absorbent,
regenerating
tower
replenishment
170 × 100
kg/
tCO2
m2
ཞ48
ཞ17000
The total investment is the sum of the construction investment, the
construction period interest, and the paving working capital. In contrast,
the paving working capital is not considered for the time being.
The total investment is 1329.4 million CNY.
7.2. Cost estimated
CO2 capture cost estimated based on following conditions:
(1) The unit operates estimated at 8000 h/ a year.
(2) The primary cost consumption and unit price are shown in the
following table:
(3) The net salvage value rate is 3%, under the precondition that
fixed assets depreciation life is 12 years.
(4) The staff of this project all depends on The Shengli power plant,
not including the labor wages and welfare.
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International Journal of Greenhouse Gas Control 110 (2021) 103423
S. Lu et al.
Table 18
Discharge of waste liquid.
1
2
3
Name of the wastewater
Discharge
Ingredient
Concentration
Character
Emissions control advice
Amine recovery heater
residue
Deep purification tower
drainage
Carbon capture system
cleaning water
2000t/a
N- acetyl ethanolamine, amino acetic acid, etc
/
interval
The boiler burning
Sodium sulfate, sodium nitrate, sodium hydroxide , and
sodium chloride, etc
amine liquid
<1wt%
continuous
<3wt%
interval
Industrial wastewater
treatment system
Industrial wastewater
treatment system
3
84 m /h
3000 m3/
time
(5) Maintenance and repair fee: calculated at 3.0% of the original
value of the fixed assets (deducting the interest during the con­
struction period).
(6) Financial expenses: mainly include interest on working capital
and interest on long-term borrowings. Interest on loans is calcu­
lated by the method of paying interest on principal repayment of
the same amount.
(7) After regenerated heating power plant condensate directly, the
power plant can save heat and other costs of 44.28 million CNY
per year.
Table 19
List of noise equipment.
1
2
3
4
Major noise source
Centrifugal
pump
Induced
draft fan
Metering
pump
21 in quantity
Noise source sound level
Number dB (A)
Operating room sound
level dB (A)
Noise control
16
≤85
3
≤85
2
≤80
70ཞ80
8 h of chemical contact time in the production
workshop and workplace shall not exceed 85dB
(A)
According to the above estimation of consumption and price pa­
rameters, the annual total unit cost of the first CO2 station of the power
plant is 285.91 CNY /t.
Table 20
Energy consumption of capture part.
Serial
number
Name
Unit
1
Electriccity
2
Desalted
water
10
MWh/
a
104t/a
4
Quantity
12413.3
12
Convert to
standard
coal
coefficient
Unit
0.1229kg
of SCE/
(kW.h)
0.4857 kg
of SCE/t
4
3
Steam
10 t/a
272
72.81 kg of
SCE/t
4
Fresh
water
104t/a
300
0.0857kg
of SCE/t
Total
Unit energy consumption
7.3. Operating revenue estimation
Quantity
Operatingrevenue = CO2 salesrevenue + carbontrading
10 kg
of
SCE/a
104 kg
of SCE
/a
104 kg
of SCE
/a
104 kg
ce/a
104 kg
of SCE
/a
kg of
SCE/
tCO2
Based on the above-mentioned pricing principle, the CO2 sales price
is determined on the condition that the internal rate of return reaches
8% after the total investment income tax.
1525.6
5.824
Annualoperatingincome = totalannualproduction × salesprice
19804.3
25.71
21361.4
106.8
VAT = currentoutputtax − currentinputtax
(4)
Urbanmaintenanceandconstructiontax = businesstax × 7%
(5)
Educationsurcharge = businesstax × 5%
(6)
7.4. Financial evaluation
Item
Unit
Quantity
Convert to
standard
coal
coefficient
Unit
Quantity
1
Electriccity
104kW•h/
a
20160
0.1229kg of
SCE/(kW.h)
2477.7
2
Steam
104t/a
6.4
68.19 kg of
SCE/t
3
Freshwater
104t/a
100
0.0857kg of
SCE/t
104kg
of SCE/
a
104 kg
of SCE
/a
104 kg
of SCE
/a
104 kg
of SCE
/a
kg of
SCE
/tCO2
Unit energy consumption
(3)
Carbon trading is based on the trading price of 18.6 CNY /t in
Tianjin, China on December 20, 2020
(1)Profit and profit distribution
Based on the Enterprise Income Tax Law of the People’s Republic of
China (effective from January 1, 2008), the income tax rate is 25%.
(2)analysis of profitability
According to the People’s Republic of China’s law on enterprise in­
come tax law regulation, 25% of income tax according to the amount of
taxable income. The statutory surplus reserve fund shall be drawn at
10% of the net profit after income tax.
(3)Solvency analysis
According to the payment method of equal amount of principal
repayment interest, the project shall repay the construction investment
loan. The working capital loan shall be repaid in the second year after
borrowing and use, and the interest shall be included in the total cost of
the year. The repayment period of the loan shall be considered as 15
years.
(4)Financial viability analysis
It can be seen from the cash flow statement of the financial plan that
the cash inflow of operating activities in each year during the calculation
period is greater than the cash outflow, indicating that the project has
economic viability.
Table 21
Energy consumption of Compression and drying part.
Total
(2)
436.4
8.6
2922.7
14.6
8
S. Lu et al.
International Journal of Greenhouse Gas Control 110 (2021) 103423
Table 22
Consumption and price parameters.
Serial number
Name
Consumption
unit
quantity
Unit price (excluding tax)
unit
amount
1
1.1
1.2
1.3
1.4
1.5
1.6
2
2.1
2.2
2.3
2.4
3
Capture device
Equipment power consumption
Desalted water
Steam
Freshwater
NaOH
Amine liquid
Compression, drying ,and liquefaction
Equipment power consumption
Steam
Adsorbent
Fresh water
Sewage treatment fee
/
104kW•h/a
104t/a
GJ/h
104t/a
104kg/a
t/a
/
104kW•h/a
GJ/h
/
104t/a
/
/
12413
12
777.93
300
94.4
2000
/
20160
18.49
/
80
/
/
CNY/kW•h
CNY /t
CNY /GJ
CNY /t
ten thousand CNY /year
year/t
/
CNY/kW•h
CNY /GJ
ten thousand CNY /a
CNY /t
CNY /t
/
0.5787
21.3
32
2.725
380
35000
/
0.5787
32
70
2.725
12.98
Remark
/
/
/
By steam calorific value
/
/
/
/
/
by steam calorific value
/
/
equivalent to one ton of CO2 products
Table 23
Profitability analysis.
Rangeability
-20%
-15%
-10%
-5%
0%
5%
10%
15%
20%
Investment in
fixed assets
Operating cost
CO2 yield
Product price
11.30%
10.37%
9.52%
8.72%
8.00%
7.33%
6.70%
6.10%
5.53%
15.91%
-4.57%
-4.57%
14.06%
0.03%
0.03%
12.15%
3.25%
3.25%
10.14%
5.75%
5.75%
8.00%
8.00%
8.00%
5.69%
10.29%
10.29%
3.13%
12.45%
12.45%
0.16%
14.46%
14.46%
-3.51%
16.33%
16.33%
Fig. 3. Sensitivity analysis diagram.
7.5. Uncertainty analysis
(1) Break-even analysis
The break-even point of the project (expressed in the utilization rate
of production capacity) is calculated by the normal year during the
second year of the operation period (peak production year):
It is estimated that the average break-even point during the project’s
operation period is 62.49%; that is, the enterprise can break even when
the annual sales volume of CO2 reaches 1,249,800 tons.
(2) Sensitivity analysis
BEP = Fixedtotalcost/(salesrevenue − Variablecost − Operatingtaxesandsurcharges)
×100%
9
(7)
S. Lu et al.
International Journal of Greenhouse Gas Control 110 (2021) 103423
According to the project’s actual situation, fixed asset investment,
gas transmission volume, operating cost, and gas selling price are taken
as sensitivity factors to measure the impact of their changes on the
economic benefits of the project. Fig. 3 shows the sensitivity analysis
results.
(3) CO2 pricing
After the above analysis, based on the after-tax internal rate of return
(IRR) of 8%, when the ex-factory price of CO2 is 301.84 CNY/t
(excluding tax), it is economically feasible.
(4) During the operation period of the recommended scheme; the
average break-even point is 62.49%. That is, the enterprise can
break even when the annual sales volume of CO2 reaches
1,249,800 tons. Based on the after-tax internal rate of return
(IRR) is 8%, when the first station of CO2’s ex-factory price is
301.84 CNY /t(excluding tax), it is economically feasible.
Declaration of Competing Interest
None.
8. Conclusion
References
(1) Chemical absorption method is used for flue gas decarburization.
The selected absorbent has a higher absorption capacity, stronger
anti-oxidation and degradation performance, lower energy con­
sumption for regeneration, and a broader application prospect.
(2) A new energy-saving process of "interstage cooling + MVR heat
pump + desorption heat energy recovery" is applied, and the
comprehensive regeneration energy consumption of the project is
less than 2.2 GJ/tCO2. The energy consumption level of regen­
eration reaches the leading level of flue gas carbon capture
demonstration project.
(3) The total investment of this project is the sum of construction
investment, interest during the construction period, and working
capital for laying the foundation. The total investment (excluding
tax) is 1329.4 million CNY.
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10