BIOMASS. Master School of Province de Liege - Industrial Engineer Department. Course: Buildings and HVAC Systems - 2nd Master Academic year:

Transcription

1 BIOMASS Master School of Province de Liege - Industrial Engineer Department Course: Buildings and HVAC Systems - 2nd Master Academic year: Teacher: MASY Gabrielle Authors: Gilles SAMSON, Fabrice VADACCA, Xavier SAP and Julien DELINCE

2 Biomass, what does it mean?! "Biomass stands for all organic ma2er with a vegetable or animal origin which can become a source of energy by combus:on.! 3 forms of useful energy: - heat - electricity - driving force of movement

3 Biomass is classified into 2 main categories depending on the humidity rate: 1. Dry biomass

4 2 procedures for dry biomass:! CombusUon : it s a complete oxida:on of the biomass to produce heat. Hot water or steam produced in the process supplies an en:rely conven:onal central hea:ng system (E.g.: wood stove or industrial boilers).! GasificaUon: it s the thermal decomposi:on of the solid biomass in a specific reactor (called gasosphère) in order to obtain a combus:ble gas.

5 2. Wet biomass BiomethanaUon: organic material undergoes an anaerobic fermenta:on in a digester, and gives a methane- rich biogas. - > to produce heat - > to produce electricity

6 3. Biofuels! Biodiesel: created from a reac:on between oil (rapeseed, sunflower) and alcohol. [Yellow rape fields]! Bioethanol : created from a mixture of fermented sugar and gasoline.

7 Biomass producuon: - > Plants absorb carbon dioxide (CO 2 ) and renew the stock of oxygen in our atmosphere. Photosynthesis produces the main cons:tuent of plants: the carbohydrates. - > CO 2 emissions from wood- fire boiler and combus:on of biogas are neutral as far as greenhouse effect is concerned.

8 The funcuoning of biomass boilers OperaUng principles: The biomass combus:on can insure the produc:on of hot water for hea:ng or con:nual supply of hot water. In order to achieve this, the biomass generator provides thermal energy to a heat transfer fluid. In this case, it uses water. A biomass boiler consists: - Furnace in which you can see the fuel degrada:on and the igni:ng flame. This fireplace is previously supplied with biomass by a conveyor system from the fuel storage silo - A combus:on chamber - A heat exchanger: where the thermal energy produced from biomass in the chamber and the flue gases will be exchanged with the coolant (water)

9 ! Wood log boiler: Different types of biomass boilers: The use of firewood is oven reserved for auxiliary hea:ng, because of the need to load the equipment with logs several :mes a day. However, technologies more and more efficient can jus:fy the choice of central hea:ng with logs, especially when hea:ng needs are important and when the resource is abundant and cheap.

10 Different types of biomass boilers:! Shredded wood boiler or wood chip boiler: The wood chip boiler has a higher comfort in use than the wood log boiler: the opera:ng principles are similar to an oil or gas boiler and it is fully automa:c. However, the investment is quite high and the bulky fuel requires a storage silo. This type of boiler can only be considered for at least 250m ² of living space.

11 Different types of biomass boilers:! Granules or pellets boiler: Fully automated, these boilers are fired by wood pellets that are stored in a silo. They are sent by a worm in the furnace. The supply, the burning and the smoke extrac:on are done automa:cally. This type of boiler has a high efficiency (90%) which is similar to a fuel boiler or an oil boiler. The granules have a higher calorific value than the chips but they are more expensive.

12 Several kinds of biomass fuels for boilers 1. Barks of trees, a basic waste of wood industry: - > Be2er for high powerful systems.

13 2. Sawdust: Come from the cu_ng of tree trunks. Easier to use in a smallest hea:ng system.

14 3. wood pellets: Come from sawdust compacted. More used in small and middle biomass boilers.

15 4. wood chips: Come from the crushing of wood witch and also come from recycling programs.

16 5. Other kinds of biomass fuels: - > From agriculture - > Ethic problema:c

17 Values of different kinds of biomass fuels

18 PosiUve and negauve aspects of biomass PosiUve aspects:! Biomass is considered as being carbon dioxide (CO 2 ) neutral.

19 ! Renewable source of energy! PosiUve impact on the local economies: Local jobs in produc:on, transporta:on, collec:on, packaging and selling.! Local producuon reduces the cost of transport and the risks related to fossil fuels in foreign country (Middle- East, Russia). Wood energy is cheaper than gas and fuel oil, at equivalent calorific value. Wood energy price doesn t fluctuate much (1) [Wood pellet factory] [Oil refinery]

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21 ! Biomass is a solu:on to use organic waste as combus:ble material: - Agricultural residues (manure) - Wood residues (sawdust, wood- pellet, unusable part of trees) - Human ac:vity residues (sludge, household waste)

22 NegaUve aspects:! Storage space for wood energy ; fill the wood- burning furnace manually.! Overexploita:on of the woody biomass would be harmful for the natural environment! Household waste contain inert components which must be treated aver burning

23 ! The net calorific value of biomass is low contrary to fossil fuels: - From 8000 to kj/kg for household waste - From 5760 to kj/kg for wood residues. Wood- pellets have the highest calorific value concerning wood products : kj/kg - From to kj/kg for wood log - About kj/kg for fuel oil (1kwh = 3600 kj)

24 ! Biofuels (agrofuels) : Biomass is interes:ng when it comes from by- products (wood residues, waste). Biofuels (rape) come from energy crops and these crops may occupy areas to the detriment of food- producing farming, forests, swamp and so on. - > It can be a threat for the ecosystem, the carbon sink, the price of food products and the water reserves. [Yellow rape fields:]

25 SoluUon for our engineering school: Wood- pellets boiler Boiler cost : around Storage space : around Power : 1,5 MWa2

26 Thank you for listening