http://uabioconf.org/

1. Silesian University of Technology
Institute of Power Engineering and Turbomachinery
www.imiue.polsl.pl
Use of the Stirling engine in a cogeneration
system based on a biomass gasification process
Łukasz Bartela
Janusz Kotowicz
Klaudia Dubiel
Leszek Remiorz
Anna Skorek-Osikowska
Kiev, 21.09.2017

2. www.imiue.polsl.pl
2
THE MOTIVATIONS OF THE RESEARCHERS
1. Pro-ecological policy of the European Union: 2020 package sets three key targets:
• 20% cut in greenhouse gas emissions (from 1990 levels),
• 20% of EU energy from renewables ,
• 20% improvement in energy efficiency.
2. National biomass sources,
3. Clasification of biomass and priority of disposal waste biomass,
4. Thermal gasification as attractive technology for utilization of waste biomass,
5. Stirling engine for production of additional electricity.
Bartela Ł., Kotowicz J., Dubiel K., Remiorz L., Skorek-Osikowska A.
„Use of the Stirling engine in a cogeneration system based on a biomass gasification process”

3. www.imiue.polsl.pl
3
THE ANALYZED SYSTEMS
 Reference CHP system
Bartela Ł., Kotowicz J., Dubiel K., Remiorz L., Skorek-Osikowska A.
„Use of the Stirling engine in a cogeneration system based on a biomass gasification process”
 Advanced CHP system
GG GC GCI
PE
Gasification Unit Gas Cleaning Unit Piston Engine Unit
SE
Stirling Engine Unit
biomass0
1 process gas
2 air
3 exhaust gas
4 water
5 solid waste
01 11
5121
11' 12 13 14
32
43
42
41
5244
33
31
DH
TC
HEL
HEL
HEL
G
22 HEH
GB
Gas Boiler
GG GC GCI
biomass0
1 process gas
2 air
3 exhaust gas
PE
4 water
5 solid waste
Gasification Unit Gas Cleaning Unit Piston Engine Unit
01 11 12 13 14
32
43
42
52445121
33
31
TC
HEL
HEL
HEL
G
22 HEH
41
DHGB
Gas Boiler

4. www.imiue.polsl.pl
4
THE MAIN ASSUMPTIONS
Parameter Symbol Value Unit
Cold gas efficiency 63 %
Cleaning unit efficiency 95 %
Gas temperature at gasification unit outlet t11 950 °C
Gas temperature at the inlet to gas cleaning unit t12 40 °C
Mass fraction of biomass C
H
O
N
S
Moisture
Ash
0.4163
0.0493
0.3822
0.0016
0.0030
0.1460
0.0043
-
-
-
-
-
-
-
Lower Heating Value of biomass LHV 14200 kJ/kg
Volume fractions of the main components of the
gas from gasification process
H2
CH4
CO
CO2
N2
H2O
5.9
1.7
19.8
7.5
44.3
20.8
%
%
%
%
%
%
Bartela Ł., Kotowicz J., Dubiel K., Remiorz L., Skorek-Osikowska A.
„Use of the Stirling engine in a cogeneration system based on a biomass gasification process”
0101
1111
GG
LHVm
LHVm






2112
1313
GCI
LHVm
LHVm







5. www.imiue.polsl.pl
5
SE
11 11'
Stirling Engine Unit
 The degree of cooling of the gas,
THE STRLING ENGINE
 The Stirling engine numerical model,
Bartela Ł., Kotowicz J., Dubiel K., Remiorz L., Skorek-Osikowska A.
„Use of the Stirling engine in a cogeneration system based on a biomass gasification process”
'1111SE TTT 
.
0.20
TSE, K
0.21
0.24
0.25
0.26
0.28
0.30
100 600300250
ηelSE, -
500400200
0.27
0.22
450 550350150
0.23
0.29
650
Diagram of the calculation models of the Stirling engine:
1 - crankshaft, 2 - connecting rods, 3 - piston cold exchanger,
4 - workspace of the cold exchanger, 5 - pipeline, 6 -
regenerator, 7 - pipeline, 8 - workspace of the hot exchanger, 9
- piston hot exchanger, FT - a force resulting from difference
between the pressure of working gas and the pressure in the
crankcase
 The efficiency characteristics of the
Stirling engine as a function of the
degree of cooling of the raw gas
SET

6. www.imiue.polsl.pl
6
Bartela Ł., Kotowicz J., Dubiel K., Remiorz L., Skorek-Osikowska A.
„Use of the Stirling engine in a cogeneration system based on a biomass gasification process”
THE TWO TYPES OF USERS OF HEATING NETWORK
0
tout, °C
0.1
0.4
0.5
0.6
0.8
1.0
-20 24-4-8
Q, MW
164-12
0.7
0.2
12 200-16
0.3
0.9
28
1.1
8
.
CASE A
CASE B
The characteristics of the heat demand for heating networks
supplying industrial consumers (CASE A) and municipal
(CASE B)

7. www.imiue.polsl.pl
7
ECONOMIC ASSUMPTIONS
Bartela Ł., Kotowicz J., Dubiel K., Remiorz L., Skorek-Osikowska A.
„Use of the Stirling engine in a cogeneration system based on a biomass gasification process”
Parameter Value Unit
Annual working time of system 7000 h
Purchase price of biomass 2 EUR/GJ
Purchase price of natural gas 9 EUR/GJ
Sale price of electricity 50 EUR/MWh
Sale price of heat 10 EUR/GJ
Unit operating cost 0.5 EUR/MWh
The discount rate 4.86 %
,
I
NPV
NPVR 
where: NPV - net present value, I - investment cost.
In order to ensure the production of heat according
to the assumed characteristics of heat demand, a
gas boiler can be installed in the system as the peak
heat source. The boiler output is selected to ensure
maximum NPVR value.
 REFSESE NPVRNPVRii ADV
b

 Net Present Value Ratio (NPVR)
 Border unit investment cost on the Stirling engine
el_PEPEchbGCGBGBPEGCGBREF NiEiQiIIII  
95.895)ln(72.59 chbGC  Ei 
14.480)ln(59.34 chbPE  Ei 
506.0
GBGB 75.984

 Qi 
el_SESEREFSEREFADV NiIIII 

8. www.imiue.polsl.pl
8
RESULTS
Bartela Ł., Kotowicz J., Dubiel K., Remiorz L., Skorek-Osikowska A.
„Use of the Stirling engine in a cogeneration system based on a biomass gasification process”
REFERENCE SYSTEM ADVANCED SYSTEM
Parameter CASE A CASE B CASE A CASE B
ΔTSE, K - - 100 300 500 100 300 500
Nel
PE,kW 473.10 282.73 499.27 559.76 631.85 299.14 337.26 383.20
Nel
SE, kW - - 15.92 51.00 88.84 9.54 30.73 53.88
QCHP, kW 1000 597.6 1000 599.16 602.52 606.48
QGB,kW 0 402.4 0 400.84 397.48 393.52
Ėchb, kW 2155.34 1288.03 2274.81 2555.65 2888.71 1362.98 1539.83 1751.95
Ėchg, kW 0 423.58 0 421.94 418.40 414.23
NPVR, - 0.36 -0.65 0.36 -0.65
ib
SE, EUR/kW - - -1650.45 -1820.13 -1970.69 2860.78 2623.02 2493.35
Eel_a, kWh 3311735 1979093 3606378 4275297 5044816 2160797 2575952 3059580
QCHP
a, kWh 7000000 2708204 7000000 2710411 2714586 2719279
Qa, kWh 7000000 2855478 7000000 2855478
Echb_a, kWh 15087372 9016214 15923697 17889559 20220989 9540842 10778817 12263626
Echg_a, kWh 0 155025 0 152701.5 148306.9 143367.3
GG GC GCI
PE
Gasification Unit Gas Cleaning Unit Piston Engine Unit
SE
Stirling Engine Unit
biomass0
1 process gas
2 air
3 exhaust gas
4 water
5 solid waste
01 11
5121
11' 12 13 14
32
43
42
41
5244
33
31
DH
TC
HEL
HEL
HEL
G
22 HEH
11
REFERENCE SYSTEM
ADVANCED SYSTEM
GB

9. www.imiue.polsl.pl
9
CONCLUSIONS
 The electric power of the system, and thus the quantity of utilized biomass increases
along with ΔTSE,
 In the case of cooperation with industrial customer, there was no need to install of the
gas boilers,
 The results of the analyzes indicate that cogeneration systems based on gasification
of the waste biomass in the case of cooperation with industrial customer can be
economically viable,
 In the case of municipal consumers the Stirling engine installation can improve
profitability indicators, but the final results depends on the sales price of electricity,
purchase price of Stirling engine and potential profits due to the waste biomass
disposal,
 The integration seems to be more justified for the lower degrees of cooling of the gas.
Bartela Ł., Kotowicz J., Dubiel K., Remiorz L., Skorek-Osikowska A.
„Use of the Stirling engine in a cogeneration system based on a biomass gasification process”

10. www.imiue.polsl.pl
10
Thank you for attention!
Bartela Ł., Kotowicz J., Dubiel K., Remiorz L., Skorek-Osikowska A.
„Use of the Stirling engine in a cogeneration system based on a biomass gasification process”
Scientific work funded by the National Science Centre within the framework of the
research project No. 2014/13/B/ST8/01869.