China's waste heat power generation: status quo & future

Byswb

Updated Wed, 01 Apr 2009 00:00:00 GMT

Ms. Zeng Xuemin, Vice President of China Cement Association, addressed a report named WHG Lifts China's Cement Industry to New High Level at the Fifth China International Waste Heat Generation Conference held in Shanghai, Mar. 27. The outline of her speech is as follows:

1.      General Info about China's WHG
1)      By the end of 2008, NSP cement accounts for 60%+ of China's total cement production.
2)      Cement project EPC all over the world; cement equipments export.
3)      During the 11th-Five-Years(2006-2010), Low temp. waste heat recovery station emerge rapidly. By 2008, 263 NSP clinker production line are equipped with WHG plants with a total installed capacity of 1662MW.
 
2.      A History of China's WHG plant
1)      1953-1989,  290 hollow kiln high temperature WHG stations;
2)      1990-1996,
Cement kiln mid-and-low temp. waste heat generation with afterburning boiler.  And
Pure low temp. waste heat generation technology. Eg. 6480kW pure low temperature WHG plant for 4000t/d cement kiln in Ningguo Cement Plant (now known as Anhui Conch Cement)----imported from Japan KHI.
3)      1996-2005, promote "cement kiln mid-and-low temp. waste heat generation with afterburning boiler" and "Pure low temp. waste heat generation technology".
By the end of 2005, there were 28 sets of mid-and-low temp. WHG generators with afterburning boilers in 36 NSP lines.  With domestic equipments and technology, China established pure low temp. WHG plants in 12 NSP lines with installed capacity ranging from 2.0MW, 3.0MW, 6.0MW to 7.0 MW.
4)      2006-present, plenty of WHG plants are put into operation. By 2008, 263 NSP clinker production line are equipped with WHG plants with a total installed capacity of 1662MW.
 
3.      China's WHG Techn & Equipments
1)      Basic principles
Low temp. WHG tech. in cement industry means, in clinker production of new type dry process and by means of waste heat recovery facility-waste heat boilers, exchanging and recovering a mass of waste heat contented in cooler exhaust gas and preheater exhaust gas, and producing superheated steam to drive turbine which will transform heat energy into mechanical energy, and finally driving the generator to produce electricity to be used in cement production.
 
Exhaust gas      AQC boiler & SP boiler      electricity power
 
2) Pure low temp. waste heat power generation-----technology & key parameters
The core of China's WHG techn: thermodynamic system. 3 modes: Single Pressure System, Compound Flash Evaporation System, Dual Pressure System
Take 5000t/d NSP clinker line for example. Can set up a 9MW pure low temperature WHG plant by using the waste heat resources produced in the kiln head and tail. Main equipments include: steam turbine, generator, SP boiler & AQC boiler.
 
 
Chart 1.  Main WHG equipments & relative parameters
No.
Name of the Equipment
Set
Main technical parameters
1
steam turbine
l
Rated power:    9MW
Rated main steam pressure: 1.25MPa(a)
Rated exhaust steam pressure: 0.008MPa(a)
Rated main steam temperature: 325℃
Rated rotational speed:    3000r/min
Rated vapor consumption rate:  5.2kg/kWh
2
Generator
1
Rated power:    9MW
Rated rotational speed:    3000r/min
Frequency:        50Hz
Efficiency:        96.5%
3
SP waste heat boiler
1
Inlet exhaust gas:  340000m3/h (standard)
Inlet gas temperature:330℃~340℃
Outlet gas temperature:220℃
Air leakage rate:      3%
Rated main steam pressure:    1.35MPa(a)
Rated main steam temperature:310℃
Main Steam flow:    25t/h
4
AQC boiler
1
Inlet exhaust gas:  240000m3/h (standard)
Inlet gas temperature:350℃~360℃
Outlet gas temperature:100℃
Air leakage rate:      2%
Rated main steam pressure:    1.35MPa(a)
Rated main steam temperature:330℃
Main Steam flow:    l8t/h
 
 
Chart 2 .Main Technical & Economic Index
No.
Item
Indicator
Remarks
1
Installed capacity       (MW)
9
 
2
Average generation power     (kW)
8020--8710
 
3
Power generated from waste heat (kWh/t-cl)
35--38
Based on 5500t/d line
4
Clinker sintering thermal consumption (kg/t-cl)
106--110
 
5
Average annual generation cost    (Yuan/kWh)
0.10--0.16
 
6
Total investment      (mln yuan)
60--70
 
7
Capital return period      (year)
3--4
 
 
 
4.      Low temp. waste heat generation station construction & operation
1)      Waste heat utilization: Modes & Selection Principles
 
2)      WHG construction modes:
A.      Traditional mode;
B.      EPC, 60% of China WHG construction market.
C.     BOT, 10%.
    3) Waste heat generators put into operation
 
 
Chart 3.  Waste heat generators put into operation & clinker lines (China)
Year
line
Generator (set)
Installed capacity (MW)
Clinker production capacity  (thousand tons/year)
1997~2005
13
14
50
11190
2006
15
14
65.5
14600
2007
86
59
571
101090
2008
149
106
975.2
158990
Total
263
193
1661.7
285870
2009 (est.)
232
181
1676.8
27670
 
 
Chart 4. WHG to be put into operation abroad in 2009
Country
line
Generator
Installed capacity
(MW)
Clinker production
(thousand tons/year)
Thailand
9
6
102.2
18190
Pakistan
9
4
52.6
100l0
India
7
5
48
8800
Vietnam
2
2
22.5
3880
Turkey
2
l
18
3100
Philippine
1
l
4.5
780
Total
34
22
247.8
44760
 
 
Chart 5.  General index of WHG production lines
 
Thermal consumption
(kg/ton-clinker)
Power generated
by waste heat
(kWh/t-cl)
Cost of power generated
by waster heat
(yuan/kWh)
Outside electricity price
(yuan/kWh)
 
China (average)
 
37-42
0.12--0.16
0.5--0.6
Anhui province
115.5
37.35
0.06--0.08
0.51--0.64
Zhejiang province
120.48
29.91
0.09--0.25
0.54--0.66
Shandong province
112.92
28.57
0.167--0.228
0.57--0.67
Note: Anhui, Zhejiang & Shandong are China's leading cement manufacturing regions.
 
4) Foreign WHG projects contracted by Chinese Companies
China WHG players’ advantages.
Entering Asian markets.
Examples: Sinoma-EC contracted two generators of Thailand's SCG, with an installed capacity of 27MW.  Conch Kawasaki contracted a 9.1MW waste heat generator in #6 line for Thailand's SKK cement plant.
Other Chinese EHG players: Dalian East, Citic Heavy Industries, Hangzhou Zhongke Energy Conservation, etc.
 
5.      Benefits of WHG
1)      Economic Benefits
For WHG projects, the average cost for per KW is 6500-7000 yuan. The cost of power generated from waste heat is usually 0.12-.016 yuan/kwh (depreciation cost: 37-39%, Maintenance expense: 25-28%, others: 18-22%. ) In 2008, the average price of electricity purchased outside is 0.63 yuan/kWh. Electricity generated by waste heat can meet 1/4--1/3 of the total electricity consumption of the cement plant. Capital return period is between three to four years.
2) CDM Benefits
A 9MW waste heat generator in a 5000tpd line will reduce 20 thousand tons of CO2. 20000*10 euros (average intnl CO2 price )=1500-2000 thousand yuan.
3) Environmental Benefits
 
6. WHG Market
Chart 6.  China's WHG Installation: Status Quo & Future

 
2008 (total)
2009 (est.)
2010 (est.)
2010(total, etimated)
NSP lines(put into operation)
909
100
50
1050
Clinker production capacity (thousand tons)
741,010
 
 
860,000
Lines with WHG
263
250
250
760
Installed capacity (MW)
1662
 
 
5200
Lines unsuitable for WHG
200 (est.)
 
 
200 (est.)

GO ABROAD! ENTER OTHER FIELDS!
 
7. Several problems concerning China's WHG industry