Sustainable Energy Technologies MSE Biomass Eduard Latõšov

Nature of biomass Contents Resources Utilisation Technologies Planning Summary

Nature of biomass

Biomass, mainly in the form of wood, is the oldest form of energy used by humans. Traditionally, biomass has been utilized through direct combustion, and this process is still widely used in many parts of the world. Source: Fireplace-Part-1-of-2.aspx Read more: Biomass resource facilities and biomass conversion processing for fuels and chemicals, Ayhan Demirbaş, Energy Conversion and Management Volume 42, Issue 11, July 2001, Pages 1357–1378

Source: Nature of biomass

Source: Traditionally, direct combustion. Now….

Nature of biomass Traditionally, direct combustion. Now….

Nature of biomass Classification

Nature of biomass Manual for biofuel users Author: Villu Vares, Ülo Kask, Peeter Muiste, Tõnu Pihu, Sulev Soosaar, Tallinna Tehnikaülikool, Author of foreword: Gudrun Knutsson Classification

Manual for biofuel users Author: Villu Vares, Ülo Kask, Peeter Muiste, Tõnu Pihu, Sulev Soosaar, Tallinna Tehnikaülikool, Author of foreword: Gudrun Knutsson Nature of biomass Classification

Nature of biomass Sustainable?/!

Nature of biomass The critical difference between biomass fuels and fossil fuel, is that of fossil and contemporary carbon. Burning fossil fuels results in converting stable carbon sequestered millions of years ago into atmospheric carbon dioxide (when the global environment has adapted to current levels). Burning biomass fuels however, returns to the atmosphere contemporary carbon recently taken up by the growing plant, and currently being taken up by replacement growth. Source: Sustainable?/!

Source: Nature of biomass Sustainable?/!

Nature of biomass

Sustainable?/!

Nature of biomass Properties

Nature of biomass Components of solid fuel Properties

Nature of biomass The following relationship is valid between the ash content in the dry matter and that in the as-received fuel: A = Aar x 100/(100 – Mar), where A is the ash content and M the moisture content. As the moisture content of fuel varies a lot, in reference tables the content of ash and volatiles is given on dry matter basis. Properties Components of solid fuel

Nature of biomass The calorific value is usually expressed in MJ/kg or kJ/kg The net (lower) versus gross (higher) calorific values The higher calorific value is calculated assuming that the water vapour in flue gas both from the fuel moisture content and as a combustion product of hydrogen has completely condensed. The condensation heat of water vapour in flue gases is not taken into account for calculation of the lower calorific value. The higher the moisture content and hydrogen content are, the bigger is the difference between the gross (higher) and net (lower) calorific values. Properties Calorific value

Nature of biomass Mostly, the flue gas is discharged from the boiler to the stack at the temperature of over 100 °C, i.e., at the temperature much higher than the dew-point and under such conditions the condensation energy of water vapour remains unused. Properties Calorific value

Nature of biomass Properties Calorific value

Nature of biomass Properties The calorific value can be either that of a moist (ar), dry (d) or dry ash-free (daf) fuel. The calculation formulae for the net (lower) and gross (higher) calorific values are (Hd – hydrogen content by the weight % in dry fuel; calorific value in MJ/kg): Calorific value

Nature of biomass Fusibility of ash 1 – the initial state: before heating the peak of ash cone is sharp; IT – initial point of deformation: the sharp peak is rounding; ST – softening temperature, the ash cone deforms to such extent that the height of the structure reduces to the size of its diameter (H = B); HT – the point of formation of hemisphere or, the cone collapses and becomes dome- shaped (H = 1/2·B); FT – flow temperature, the liquid ash dissipates along the surface. beginning of deformation (initial temperature) IT = 1150 – 1490 °C; softening temperature ST = 1180 – 1525 °C; the point of hemisphere formation HT = 1230 – 1650 °C; flow temperature FT = 1250 – 1650 °C.

Nature of biomass Fusibility of ash SLUGGING PROBLEMS

Resources

The global distribution of photosynthesis, including both oceanic phytoplankton and terrestrial vegetation. Dark red and blue-green indicate regions of high photosynthetic activity in ocean and land respectively.

Resources The earth's natural biomass replacement represents an energy supply of around EJ (3×10 21 J) a year, of which just under 2% in 1998 was used as fuel. It is not possible, however, to use all of the annual production of biomass in a sustainable manner. One analysis provided by the United Nations Conference on Environment and Development (UNCED) estimates that biomass could potentially supply about half of the present world primary energy consumption by the year Source: Ramage J, Scurlock J. Biomass. Renewable energy-power for a sustainable future. In: Boyle G, editor. Oxford: Oxford University Press; 1996

Utilisation

TOTAL Comparison of primary bioenergy demand in this roadmap and global technical bioenergy potential estimate in 2050 Source:

Bioenergy for Heat and Power Utilisation

Bioenergy for Heat and Power

Utilisation Bioenergy for Heat and Power Organisation for Economic Co-operation and Development List available here:

Utilisation Bioenergy for Heat and Power Roadmap vision of world final bioenergy consumption in different sectors

Utilisation Bioenergy for Heat and Power

Utilisation Bioenergy for Heat and Power CO2 emission reductions from bioenergy electricity and bioenergy use in industry and buildings compared to a business as usual scenario (6°C Scenario)

Cumulative technology contributions to power sector emission reductions in ETP 2014 hi-Ren Scenario, relative to 6DS, up to 2050 Utilisation

Biofuels for Transport Utilisation

Biofuels for Transport

Utilisation Biofuels for Transport

Technologies

… different technologies. Focus on direct burning.

Boiling point 100 o C pressure 760 mmHg = 0,101 MPa Boiling – without temperature increase evaporation You 2260 kJ/kg to evaporate 1 kg of H2O at 100 o C Liquid Steam Technologies Rankine cycle

Blue area – heat losses in condenser, red area – useful energy of turbine. Goal – increase red area. How? 1). Decrease condensing process (4-5) temperature (lowering the condenser pressure). 2). Increase vaporization temperature (depends on pressure). Process (1-2). 3). Increase steam superheating temperature. Superheating process (2-3). Technologies Rankine cycle

Planning

Overview of possible operating parameters and generating costs for bioenergy electricity by 2030 Overview of bioenergy power plant conversion efficiencies and cost components Capital and O&M costs

Planning CHP HEAT ONLY CHP versus HEAT ONLY

Bioenergy electricity generation costs 2010 and 2030, compared to coal and natural gas based power generation Planning LCOE

Liquid fuels

Summary Cons Energy intensive to produce. In some cases, with little or no net gain. Land utilization can be considerable. Can lead to deforestation. Requires water to grow Not totally clean when burned (NOx, soot, ash, CO, CO2) May compete directly with food production (e.g. corn, soy) Some fuels are seasonal Heavy feedstocks require energy to transport. Overall process can be expensive Some methane and CO2 are emitted during production Not easily scalable Disadvantages

Pros Truly a renewable fuel Widely available and naturally distributed Generally low cost inputs Abundant supply Can be domestically produced for energy independence Low carbon, cleaner than fossil fuels Can convert waste into energy, helping to deal with waste Summary Advantages

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