Module 1a Biomass Introduction

Transcription

1 Module 1a Biomass Introduction Contents 1. Biomass as sustainable energy source/carrier 2. Rationale for renewable energy 3. Biomass as a fuel or feedstock for chemicals slide 2/22 1 1

2 Biomass or not? slide 3/22 What is biomass? All living plant matter as well as organic wastes derived from plants, humans, marine life, and animals Biomass is storage of sunlight energy CO O sunlight 2 H 2 O catalysts C H 12 O 2 slide 4/22 2

3 Why biomass? Bioenergy Cycle slide 5/22 The short carbon cycle slide /22 3

4 Commercial Carbon Cycle slide 7/22 Why biomass? No net CO2 emissions: CO2 released by combustion of biomass is balanced by the CO2 fixation during growth in a relatively short time cycle, varying from one to several hundreds of years Advantages Disadvantages - abundantly available - low efficiency (solar energy to biomass - locally available as waste energy) (0.7%) - simple storage - storage as solid with low density - conversion to heat and power - not for urban environments - efficient instrument for extracing - diverse and inhomogeneous fuel type low concentration CO 2 from air - ecological impact sometimes not good slide 8/22 4

5 Power chain from original sources Photosynthesis storage from previous era s fossile fuels combustion - not durable - not sustainable biomass - food (muscular power) - biomass fuel P O W Photovoltaic and artificial photosynthesis E R Uneven heating up of oceans and atmosphere - Solar ponds - Focussed - Wind - Waves - Hydropower - Temperature gradients in ocean slide 9/22 3 WHY RENEWABLES? Two main reasons: To decrease fossil fuel derived carbondioxide emissions and, To offer new energy sources given the limited fossil fuel reserves. Greenhouse gas emissions and climatic changes During the last century the global temperature has risen by 0. C. Greenhouse gas emissions could significantly affect the earths climate. Renewable energy is an insurance agains possible global warming through these gases. Limited fossil fuel reserves The known coal reserves can supply the current global economy for 1500 years With a 5% economic growth, the coal reserves will last for only 87 years. Gas and oil reserves will be consumed in the next 50 years. These circumstances will create a competitive market for renewables. slide 10/22 4 5

6 Global Energy Sources 2002 slide 11/22 Expected energy consumption Source: Shell Global Solutions slide 12/22

7 Renewable Energy Use 2001 slide 13/ Energy scenario 2000 (forecast of the Shell group) Sustainable growth: 2% per jaar Renewable 500 Water/nuclear gas coal oil 0 traditional biomass Year slide 14/22 7

8 Biomass fuel upgrading Biomass consists of: combustables + water + ash Biomass is not economically combustable with a moisture content of over 0%, because heat of water evaporation approaches net heat of combustion Wet Biomass Dewatering Dry Biomass Drying Solar drying water vapour Mechanical liquid water Vapour recompression, multiple effect etc. liquid water Water separation during upgrading liquid water slide 15/22 8 Wet Biomass biological supercritical gasification HTU Pressure cooker P = 1 bar, T = 20-0 C P = 150 bar, T = 300 C phase separation water and ash Biogas (CH4), bio-ethanol phase separation water and ash Biocrude (hydrophobic oil) Pressure cooker P = 300 bar, T = 00 C phase separation water and ash H 2-rich gas 9 slide 1/22 8

9 Dry Biomass direct Slow flash combustion pyrolysis pyrolysis ash ash char+ gas ash Charcoal gasification direct pressing ash Bio-oil (organic liquid + water) fuel gas or synthesis gas liquid fuels hydrocarbons methanol etc. Vegetable oil Biodiesel 10 slide 17/22 Biomass constraints Sustainable Development Move toward sustainable energy production Energy Security Reduce dependence on imported oil Rural Economic Growth Provide new crops/markets for rural business Land Use Better balance of land use slide 18/22 9

10 Environmental issues Air Quality Reduce NOx and SO2 emissions Global Climate Change Low/no net increase in CO2 Soil Conservation Soil erosion control, nutrient retention, carbon sequestration, and stabilization of riverbanks. Water Conservation Better retention of water in watersheds Biodiversity and Habitat Positive and negative changes slide 19/22 Barriers using biomass Road transport Water competition Energy input Fire and diseases Food competition Bio diversity Erosion Limited growth ~ 20 t/ha/y Landscape nature Soil exhaustion, C, minerals Agro chemicals needed Side effects political issues slide 20/22 10

11 Bioenergy has arrived to the national and international Agendas Bioenergy is clearly multidisciplinary Energy Environment Agronomy Land tenure Health Economics Rural development Climate change Biodiversity farmers Commodities Markets Etc slide 21/22 THANKS FOR YOUR ATTENTION TERIMAH KASIH 11