ENERGY PRODUCTION FROM BIOMASS

Transcription

1 ENERGY PRODUCTION FROM BIOMASS B. Aylin Alagöz, Ph.D. Prof. Dr. Orhan Yenigün Prof. Dr. Ayşen Erdinçler Boğaziçi University Institute of Environmental Sciences İstanbul, Turkey

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4 Global Clean Energy Expected Growth 2005 to 2015 Biofuels are a growth industry in the world energy markets, especially ethanol and biodiesel.

5 ENERGY from WASTE (EfW) or WASTE to ENERGY (WtE) In 2012, the global market for waste-to-energy technologies was valued at USD 24 billion, an average annual increase of 5% from The waste to energy market is expected to reach a market size of USD 29 billion by 2015 at a Compounded Annual Growth Rate (CAGR) of 5.5% (Frost & Sullivan, 2011). The main drivers for this growth could be summarized in an increasing waste generation, high energy costs, growing concerns of environmental issues, and restricted treatment capacities. WtE would help solve these issues by reducing the waste volume and cutting down on greenhouse gas emissions.

6 ENERGY from WASTE (EfW) or WASTE to ENERGY (WtE) Process of generating energy in the form of electricity and/or heat from the wastes. There are a number of new and emerging technologies that are able to produce energy from waste and other fuels without direct combustion. Energy from waste technologies Thermal Non-Thermal

7 Bioenergy Conversion

8 Anaerobic Digestion Producing renewable energy Preventing transmission of disease Lower capital cost Production of an odorless, humus-like, biologically stable end product Hydrolysis Acidogenesis Acetogenesis Methanogenesis H 2 CO 2 NH 3 Carbohydrates Proteins Lipids Sugars Amino acids Fatty acids Alcohols Carbonic acids Volatile fatty acids NH 4 H 2 S CH 4 CO 2 Acetic acid

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12 What is meant by Biomass? Materials produced by metabolic activities of biological systems and/or products of their decomposition or conversion Materials based on carbon compounds High chemical and energetic value

13 Feedstocks for AD Organic fraction of MSW Sewage sludges Manure Fruit and vegetable processing wastes Slaughterhouse and poultry wastes Algae biomass Yard waste Energy crops and crop residues Waste paper

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16 Biogas Around the World World Bioenergy Association estimates the global substrate potential for biogas production 10,000 TWh. Total World Production is estimated to between TWh.

17 In the Europe...

18 Why the biomass renewable energy sources are quite important for Turkey? 65 Mtons of agricultural wastes generated annually from cultivation The predictions show that the annual sludge production will reach up to 911 ktons by year 2040.

19 Biomass Energy Potential Turkey possesses a variety of biomass resources like forests, agriculture and animals. Although traditionally animal dung has been used for heating and cooking purposes for many years, it is slowly being converted to modern uses of biomass energy. Type of Biomass Annual biomass potential (million tons) Energy potential (Mtoe)* Annual crops Perennial crops Forest residues Residues from agro-industry Residues from wood industry Animal wastes Other Total

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23 Biogas Cycle Solar energy Photosynthesis Animal husbandry Crop harvesting Industrial processing Human consumption Energy crops Biofertilizer H 2 O CO 2 Organic wastes Anaerobic digestion Biogas Electrical and/or thermal energy

24 Benefits of Co-digestion Crop or Crop residues High C/N ratio high carbon content Low alkalinity Lack of macro/micro nutrient Wastewater Sludge Lower C/N ratio high ammonia Higher alkalinity Rich in macro/micro nutrient Improve the C/N ratio, buffering capacity and more biodegradable substrate

25 Aim of this Study to investigate thoroughly: the biogas production potential of the anaerobic co-digestion of wastewater sludge with several agricultural products such as; energy crops cloverleaf, wheat, grass agro-wastes and manure nutshell, potato peel, olive bagasse, barley and maize silage 25

26 MATERIALS AND METHODS Sludge Substrates: Seed Sludge (Inoculum) Wastewater Sludge Inoculum: from the full-scale anaerobic digester of a big yeast factory in İzmit-Turkey Wastewater Sludge : from the recycling line of one of the largest advanced biological wastewater treatment plant located in İstanbul

27 Sludge Characteristics Parameter Unit Inoculum Sewage Sludge TS mg/l VS mg/l MLSS mg/l MLVSS mg/l COD mg/l scod mg/l TKN mg/l NH 4+ mg/l TP mg/l PO -3 4 mg/l SO -2 4 mg/l Alkalinity (as CaCO 3 ) mg/l ph Conductivity ms/cm Salinity Total Coliform cfu/100ml 2*10 6 2x10 6 Fecal Coliform cfu/100ml 2.2* x10 5 Fecal Streptococ cfu/100ml 3.2* x10 4

28 Characteristics of Biomass Products Biomass TS (%) VS (%) Nitrogen Weight (%) Carbon Weight (%) Hydrogen Weight (%) Clover Wheat Nutshell Potato Peel Olive Bagasse Maize Silage Grass Barley Silage Manure Wastewater Sludge

29 Analytical Methods Parameter Method and Special Instruments Parameter Method and Special Instruments ph ORP Conductivity COD TOC TS/VS VSS TVS Alkalinity 4500-H B Method Electrometric (APHA, AWWA- WPCF-2006) ORION SA 520 ph meter 2580 B Method (APHA, AWWA-WPCF-2006) ORION SA 520 ph meter 2510 B Method (APHA, AWWA-WPCF-2006) WTW LF 320 Conductivity meter 5220 D Method Closed Reflux, Colorimetric (APHA, AWWA-WPCF-2006) HACH COD Digester, HACH DR/3 Spectrophotometer 5310 A Method (APHA, AWWA-WPCF-2006) 2540 B (APHA, AWWA-WPCF-2006) 2540 D and E (APHA, AWWA-WPCF-2006) 2540 G (APHA, AWWA-WPCF-2006) 2320 B Method Titration (APHA, AWWA-WPCF- 2006) TKN Ammonia-N Nitrite, nitrate Phosphate Chloride Sulfate 4500 E Method Titration (APHA, AWWA-WPCF-2006) Gerhardt Vapodest Digester Apparatus 4500 E Method Titration (APHA, AWWA-WPCF-2006) Gerhardt Vapodest 12 Distillation Apparatus 4500 Method (APHA, AWWA-WPCF-2006) 4500-P E Method Ascorbic Acid (APHA, AWWA- WPCF-2006) HACH DR/3 Spectrophotometer 4500-Cl B Method Argentometric (APHA, AWWA- WPCF-2006) 4500-SO4-2 E Method Turbidimetric (APHA, AWWA- WPCF-2006) HACH DR/3 Spectrophotometer CST CST Instrument (Vesilind, 1988) VFA Gas Chromatograph HP 5890 CH 4, CO 2, O 2 Gas Chromatograph HP 6850

30 Reactor Conditions for Batch Tests Batch fed anaerobic reactors (ph around 7) 2.5 L with 1.6 L active volume 40 days of digestion Mesophilic conditions at 37 C 6.5% of initial TS contents of the reactors Inoculum to Substrate Ratio: 1/2 The bottles equipped with a V shape gas collection ports at the top. One opening for MiliGascounter (MGC) to measure the amount of biogas produced. One opening to take samples for gas composition (CH 4 and CO 2 ) analysis by HP 6850 Gas Chromatograph. (Carboxen 1010 plot GC column 30 m x 0.53 mm) equipped with a thermal conductivity detector.

31 Reactor Contents Reactors R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 Content Inoculum Inoculum + WAS Inoculum + WAS + Cloverleaf Inoculum + WAS + Wheat Inoculum + WAS + Nutshell Inoculum + WAS + Potato Peel Inoculum + WAS + Olive Bagasse Inoculum + WAS + Maize Silage Inoculum + WAS + Grass Inoculum + WAS + Barley Silage Inoculum + WAS + Manure

32 Reactor Conditions Initial ph values of the reactors were adjusted to about 7. Final ph values of the reactors ranged between The initial alkalinity concentrations in the reactors ranged between mg CaCO 3 /L. Final alkalinity concentrations ranged between mg CaCO 3 /L.

33 RESULTS AND DISCUSSION

34 Microbiology Results of the Reactors Reactors Total Coliform Initial [cfu/100ml] Total Coliform Final [cfu/100ml] Fecal Coliform Initial [cfu/100ml] Fecal Coliform Final [cfu/100ml] Fecal Streptococ Initial [cfu/100ml] Fecal Streptococ Final [cfu/100ml] R1 2.0x x x x R2 2.0x x x x R3 2.5x x x x R4 4.2x x x x R5 1.8x x x x R6 3.1x x x x R7 2.0x x x R8 2.5x x x x R9 5.0x x x x R10 1.7x x x R11 2.5x x x x10 4 1

35 Gas Analyses The daily gas production and gas content (CO 2 % and CH 4 %) are the major parameters indicating the efficiency of anaerobic digestion process. The highest methane contents of 59% and 58 % were obtained in reactors R3 and R8 containing wastewater sludge and co-substrates clover leaves and maize respectively. The lowest methane content of 39% was obtained in reactor R5 having nutshells.

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38 MECHANICAL: High Pressure Homogenizer Stirred Ball Mill Lysate Centrifuge Mechanical Jet Technique Ultrasound Pulsed Electrical Field THERMAL: Microwave Steam Explosion Liquid Hot Water Sludge Pre-treatment Methods CHEMICAL: Acid Treatment Alkali Treatment Ozone Fenton Process BIOLOGICAL: Enzyme Treatment

39 Ultrasonication Microwave Disintegration Alkali Pre-Treatment Pulsed Electric Field Application

40 Ultrasonication Ultrasonic treatment acts to mechanically disrupt the cell structure and floc matrix. Cavitation: the bubbles form, grow and undergo violent collapse. Chemical reactions: OH, HO2, H radicals and hydrogen peroxide can be formed.

41 Microwave The application of microwave irradiation for sludge pre-treatment : releases intracellular bound water and generally involves heating in the range of C. causes to a rotation of dipole molecules under an oscillating electromagnetic field provides rapid, energy-efficient heating of water to the boiling point where the cells of microorganisms are ruptured and the bound water is released.

42 Determination of Optimum Power Output and Amplitude Volume (ml) Power Output (W) Amplitude (%) Ultrasonic Power (W) Power Density (W/mL) Power Intensity (W/cm 2 ) Sample Volume (ml) Power Density (W/mL) Sonication Duration (min) SE (kj/kg TS) dt Power dt Density c Power Volume p Power Intensity Area P t SE V TS 0 M

43 SCOD (mg/l) Disintegration Degree (%) Variation of SCOD and disintegration degree with specific energy SV (mm/h) kj/kg TS 2177 kj/kg TS 4354 kj/kg TS 8708 kj/kg TS kj/kg TS kj/kg TS Specific Energy (kj/kg TS) kj/kg TS kj/kg TS Time (h) DD COD Specific Energy (kj/kg TS) SCOD SCOD Ultrasonic NaOH SCOD SCOD % Effect of Ultrasonic Disintegration on Sludge Settling Properties

44 MLSS, MLVSS (mg/l) TS, VS (mg/l) MLVSS/MLSS Effect of Ultrasonic Disintegration on Solids Concentration Specific Energy (kj/kg TS) TS TVS Specific Energy (kj/kg TS) MLSS MLVSS MLVSS/MLSS

45 Effect of Ultrasonic Disintegration on Particles Size Distribution Power Density (W/mL) Sonication Duration (min) d (0.1) (µm) d (0.5) (µm) d (0.9) (µm)

46 Selection of Appropriate Substrates Biogas Production from Different Codigestion Scenarios Effect of Single/Combined Sludge Pre-treatments Higher Organic Removal Higher Biogas Production Reactors Content R1 R2 R3 R4 R5 R6 R7 Inoculum Inoculum + Wastewater Sludge (ISR:1/1) Inoculum + Olive Pomace (ISR:1/1) Inoculum + Wastewater Sludge + Olive Pomace (ISR:1/1) Inoculum + 15 min Ultrasonically Pre-treated Wastewater Sludge + Olive Pomace Inoculum + 30 min Ultrasonically Pre-treated Wastewater Sludge + Olive Pomace Inoculum + 30 min Microwave Pre-treated Wastewater Sludge + Olive Pomace

47 Parameters Reactors R1 R2 R3 R4 R5 R6 R7 VS removal (%) Total VS removal (g) CH 4 percentage (%) Ultimate Biogas Production (L) Ultimate CH 4 Production (L) , Ultimate Biogas Yield (L/g VS removed) Ultimate CH 4 Yield (L CH 4 /g VS removed)

48 Conclusions Comparison of different batch reactor operations showed that: Anaerobic co-digestion of wastewater sludge and agricultural wastes was a more efficient option than single substrate systems from the point of biogas production. Applied pre-treatment methods enhanced the anaerobic biodegradation of the organic wastes by: Increasing the solubility of the organics and speeding up the hydrolysis step.

49 Conclusions (cont.) The anaerobic co-digestion of sewage sludge with the agricultural biomass resulted in higher methane yields compared to that of a single-substrate digestion of the sludge (except nutshell). Methane yields increased about 11-67% depending on the type of the biomass. Methane yields obtained from agricultural waste materials were compatible with those obtained from energy crops except cloverleaf.

50 Conclusions (cont.) The cloverleaf is found to be a very efficient co-substrate for the biogas production. The highest biogas and methane yields were obtained from reactor R3 having a mixture of wastewater and cloverleaf to be 0.59 L/gVSadded and 0.28 L CH4/gVSadded, respectively. The cumulative biogas production was almost ten times higher for this reactor R3 than mono-sludge digestion reactor R2. Methane yields obtained from agricultural waste materials were compatible with those obtained from energy crops except cloverleaf.

51 B. Aylin Alagöz Bogazici University Institute of Environmental Sciences Hisar Campus, Turkey Tel: Fax: