A Techno-economic Assessment of Biomass Fuelled Tri-generation System Integrated With Organic Rankine Cycle

Transcription

1 A Techno-economic Assessment of Biomass Fuelled Tri-generation System Integrated With Organic Rankine Cycle Y. Huang, Y.D. Wang, S. Rezvani, D.R. McIlveen- Wright, M. Anderson, J. Mondol, A. Zacharopolous and N.J. Hewitt Sustainable Thermal Energy Management in the Process Industries International Conference (SusTEM2011), Oct. 25 th -26 th, United Kingdom 01/11/2011 1

2 OVERVIEW Aims and objectives Description of the process ECLIPSE simulation Operating input/output data Capital cost estimation Breakeven electricity selling price (BESP) Sensitivity analyses Conclusions 01/11/2011 2

3 Aim and Objectives Aim: To perform techno-economic assessments of systems which integrate biomass Organic Rankine Cycle with the trigeneration system using ECLIPSE process simulator. Objectives: Modelling biomass fuelled ORC and a tri-generation system Mass and Energy balance of biomass fuelled ORC and tri-generation using ECLIPSE process simulator Technical assessment: Power, heat and cooling productions Process efficiencies Impact of biomass feedstock on the performance of the system Economic analysis Financial assumptions Breakeven electricity selling price (or Levelized Cost of Electricity) Sensitivity studies 01/11/2011 3

4 Biomass Fuelled Tri-generation System 01/11/2011 4

5 BIOMASS Biomass is one of the renewable energy sources which is: not intermittent not location-dependent not difficult to store. If grown sustainably, biomass can be considered as CO 2 neutral. 01/11/2011 5

6 Fuel used Three common biomass are used: Willow chips; Straw and Rice husks 01/11/2011 6

7 Fuel properties In order to evaluate the technical, environmental and economic performance of the proposed tri-generation system, especially the impact of different fuels three common biomass or biomass waste species are chosen for the simulation. 01/11/2011 7

8 Tri-generation system proposed 01/11/2011 8

9 Tri-generation Process A conventional biomass combustion process: the boiler and heat transfer section The Organic Rankine Cycle (ORC) system for power generation The waste heat is recovered from exhaust flue gases for the thermal storage and supply of hot water/central heating in the building. An ammonia absorption system, which is run by the waste heat recovered, is used to supply the cooling for the building when necessary. 01/11/2011 9

10 The application of the Trigeneration system: the selected building Energy profile of the selected hotel 01/11/

11 The software: ECLIPSE Architecture 01/11/

12 ECLIPSE Modelling: ORC Process 01/11/

13 ECLIPSE Modelling: Absorption System 01/11/

14 Technical Results (1) 01/11/

15 Technical Results (2) 01/11/

16 Overall process efficiencies vs. feedstock 01/11/

17 Typical economic factors and indices 01/11/

18 Economic Results Tri-generation system 01/11/

19 Economic Results CHP system 01/11/

20 Breakeven Electricity Selling Price vs. Feedstock 01/11/

21 Breakdowns of Breakeven Electricity Selling Price 01/11/

22 Sensitivity Analysis 1) Plant occupancy (4500 to 6500hr) 2) Specific investment costs (-30% to +30%) 3) Fuel cost (2.45 to 4.55 /GJ) 01/11/

23 BESP versus specific investment (Biomass: wood chips) 01/11/

24 CONCLUSIONS AND RECOMMENDATIONS (1) From the results and discussions, it can be concluded that: 1) It is technically feasible to use willow chips, straw and rice husk as the fuel to operate the ORC based tri-generation plant, as there is little difference between the process efficiency from one fuel to the other; 2) The process efficiency of TG is much higher than that of PO, but is lower than that of the combined heat and power (CHP) configuration; 3) The TG/CHP system with an ORC cycle would be beneficial to the building system if the heat/power ratio is in the range of 4.5 and 6.7; 4) Due to its extremely low CO 2 emissions the TG system offers a significant CO 2 saving opportunity for the building energy supplies; 01/11/

25 CONCLUSIONS AND RECOMMENDATIONS (2) 5) The overall efficiency for tri-generation fuelled by willow chips is lower than that fuelled by straw and rice husk due to its high moisture content; 6) Specific investment (SI) is founded to be very high for the ORC based tri-generation system, giving 4440 /kwe; 7) The breakeven electricity selling price (BESP) of the TG system is much lower than that of the PO option but is slightly higher than the CHP mode; 8) BESP of tri-generation is dominated by both the capital expenditure (CAPEX) and fuel cost, as shown in Figure 7; 9) Increasing plant occupancy and reducing SI and fuel cost would be beneficial for BESP. 01/11/

26 Acknowledgement This research outcome is from a joint UK- China research program funded by the Engineering and Physical Sciences Research Council of the UK 01/11/

27 Thank you for your attention. 01/11/