1. Biomass-fired combined heat and power for district heating
UET- KSK Campus
Energy Engineering
2017/11/20

2. CASE 1: HOT WATER BOILER District heating production rate: 50 MW
District heating 80 °C
Preheated air
Air, 30 °C, dry
Condensate, 53 °C
De-humidified flue gas, 53 °C
District heating 50 °C
Wet biofuel
H2O, 170 °C, 16 bar
H2O, 130 °C, 16 bar
Flue gas, 120 °C
District heating production rate: 50 MW
Annual district heating demand: 5000 hours
Fuel consumption: 2.98 kg MAF/s
Power consumption: 693 kW

3. CASE 1: PROFITABILITY ANALYSIS
Case 1: Power cost of 300 sek/MWh
Annual fuel cost [Msek]
26.1
Annual power cost [Msek]
1.04
Annual district heating revenue [Msek] 50
Cost of the flue gas condensator [Msek]
13.6
Cost of the other parts of the plant [Msek]
129.6
Total investment cost [Msek]
143.2
Depreciation [Msek]
14.3
Annual maintenace and operation [Msek]
8.07
Annual profit [Msek]
0.51
Case 3: Power cost of 700 sek/MWh
Annual fuel cost [Msek]
26.1
Annual power cost [Msek]
2.42
Annual district heating revenue [Msek] 50
Cost of the flue gas condensator [Msek]
13.6
Cost of the other parts of the plant [Msek]
129.6
Total investment cost [Msek]
143.2
Depreciation [Msek]
14.3
Annual maintenace and operation [Msek]
8.07
Annual profit [Msek]
-0.87
Case 2: Power cost of 500 sek/MWh
Annual fuel cost [Msek]
26.1
Annual power cost [Msek]
1.73
Annual district heating revenue [Msek] 50
Cost of the flue gas condensator [Msek]
13.6
Cost of the other parts of the plant [Msek]
129.6
Total investment cost [Msek]
143.2
Depreciation [Msek]
14.3
Annual maintenace and operation [Msek]
8.07
Annual profit [Msek]
- 0.18
Case 4: Power cost of 500 sek/MWh, no condenser
Annual fuel cost [Msek]
35.3
Annual power cost [Msek]
2.42
Annual district heating revenue [Msek] 50
Cost of the plant [Msek]
150
depreciation [Msek] 15
Annual maintenace and operation [Msek] 10
Annual profit [Msek]
-13

4. CASE 2: REFERENCE CASE WITH STEAM CYCLE
POWER PRODUCTION
20.6 MW
1-y-y’ 4
District heating
80 °C
Turbine y
50 °C 1 2
Condenser
FUEL DEMAND
78.1 MW y’ 3 1
HEAT PRODUCTION
50 MW
Preheater2: Closed heater
Preheater1: Open heater 5
1-y-y’ 9 1 8 6
Wet biofuel
Preheated air 7
Flue gas y 1 11
Pump 2
Steam generator 10 y
Pump 1
Trap
Legend:
1 stream number
y stream mass flow ratio

5. CASE 2: PROFITABILITY ANALYSIS
INCOMES
50 MSEK/year
41.1 MSEK/year
Heat production : MW
Power production : 20.6 MW
COSTS
42.9 MSEK/year
Fuel demand : MW
Capital : MSEK/year
Operation : MSEK/year
Maintenance : 10.1 MSEK/year
PROFITABILITY
for power price 400 SEK/MWh MSEK/year

6. CASE 3: STEAM CYCLE WITH FUEL DRYER
POWER PRODUCTION
18.8 MW FF
District heating
FUEL
DRYER
80 °C
Turbine
50 °C
Condenser
HEAT PRODUCTION
50 MW
Preheater2: Closed heater
Preheater1: Open heater
DRYED
FUEL
WET
FUEL
65,85 MW
Flue gas
Pre-heated
air
Pump 2
Steam generator
Pump 1
Trap

7. CASE 3: PROFITABILITY ANALYSIS
INCOMES
50 MSEK/year
37,6 MSEK/year
Heat production : MW
Power production : 18.8 MW
COSTS
36,2 MSEK/year
Fuel demand : MW
Capital : ,4 MSEK/year
Operation : ,46 MSEK/year
Maintenance : 8,88 MSEK/year
PROFITABILITY
for power price 400 SEK/MWh ,53 MSEK/year

8. CASE 4: STEAM CYCLE WITH LOWER STEAM DATA
POWER PRODUCTION
19 MW
P=0.7 bar
H=2.56MJ/kg
m=23kg/s
P=65 bar
T=510 ̊C
H=3,44MJ/kg
m=27kg/s 4 + -
District heating
80 °C
Turbine
50 °C 1 2
Condenser
FUEL DEMAND
79 MW 3
HEAT PRODUCTION
50 MW
Preheater2: Closed heater
Preheater1: Open heater 5 9
10Kg/sec 8 6
Wet biofuel
Preheated air 7
Flue gas 11
Pump 2
Boiler 10
Pump 1
Trap

9. CASE 4: PROFITABILITY ANALYSIS
INCOMES
50 MSEK/year
66,5 MSEK/year
(for price of 700sek/MWh)
Heat production : MW
Power production : 19 MW
COSTS
43,5 MSEK/year
Fuel demand : MW
Capital : ,2 MSEK/year
Operation : ,9 MSEK/year
Maintenance : 9,8 MSEK/year
PROFITABILITY
for power price 700 SEK/MWh MSEK/year

10. CASE 5: STEAM CYCLE WITH FLUE GAS CONDENSER
POWER PRODUCTION: 22.1 MW
HEAT PRODUCTION: 50MW
District heating 50 C
Dry
biofuel
District heating 50 C
Condensate 53 C
Flue gas 120 C
Preheated air
District heating 80 C
Flue gas to chimney
100 bars
540°C
25°C
WASTE HEAT RECOVERY: 12.2 MW
FUEL DEMAND:
82.1 MW

11. CASE 5: PROFITABILITY ANALYSIS
INCOMES
50 MSEK/year
33.2 MSEK/year
59.2 MSEK/year
Heat production : MW
Power production : MW
Waste heat recovery : 12.2 MW
Total annual revenue : MSEK/year
COSTS
45.2 MSEK/year
Fuel demand : MW
Annuity : MSEK/year
Operation and maintenance : MSEK/year
Total operating cost : MSEK/year
PROFITABILITY -15.MSEK/year

12. CASE 6: STEAM CYCLE WITH FLUE GAS CONDENSER AND INLET AIR HUMIDIFIER
POWER PRODUCTION: 21,8 MW
HEAT PRODUCTION: 50MW
District heating 50 C
Wet
biofuel
Flue gas condenser
District heating 50 C
Condensate 53 C
Flue gas 120 C
Preheated air
District heating 80 C
Humidifier for inlet air
Condensate 30 C
Inlet air humidifier
40 C
Saturated
Air 30 C
(dry)
De-humidified flue gas to chimney
100 bars
540°C
25°C
WASTE HEAT RECOVERY: 17,86 MW
FUEL DEMAND:
82,5 MW

13. CASE 6: PROFITABILITY ANALYSIS
INCOMES
50 MSEK/year
65,3 MSEK/year
17,9 MSEK/year
Heat production : MW
Power production : ,8 MW
Waste heat recovery : 17,9 MW
Total annual revenue : 133,1 MSEK/year
COSTS
45,4 MSEK/year
Fuel demand : ,5 MW
Capital : ,7 MSEK/year
Operation and maintenance : ,4 MSEK/year
Total operating cost : 134,4 MSEK/year
PROFITABILITY
for power price 400 SEK/MWh : -1,3 MSEK/year

14. CASE 7: SMALL SCALE STEAM CYCLE
480/62
Power
5,1 MW
Biomass Fuel
28.4 MW
Heat power
17,7 MW

15. CASE 7: PROFITABILITY ANALYSIS
INCOMES
17,7 MSEK/year
15,5 MSEK/year
Heat production : 17,7 MW
Power production : 5,1 MW
COSTS
15,6 MSEK/year
Fuel demand : ,4 MW
Capital : ,7 MSEK/year
Operation : ,39 MSEK/year
Maintenance : 3,55 MSEK/year
PROFITABILITY
for power price 400 SEK/MWh ,48 MSEK/year

16. PROFITABILITY ANALYSIS

17. MAIN CONCLUSIONS It is profitable with…
steam cycle if power price > 500 SEK/MWh
fuel drier if 500 SEK/MWh < power price < 850 SEK/MWh
waste heat recovery if power price > 400 SEK/MWh
If inlet air humidifier is added to a flue gas condenser