a thesis presentation on applications of woody biomass in a small scale gasification presented by:...

A thesis presentation on Applications of woody biomass in a small scale gasification Presented By: Daya Ram Nhuchhen (st109625) Committee Members: Dr. P. Abdul Salam (Chairperson) Prof. Sivanappan Kumar (Member) Dr. Charles O. P. Marpaung (Member) 1

Contents of Presentation Statements of study Objectives of study Rationale of the study Methodology of study and major findings on Specific objective 1 Specific objective 2 Specific objective 3 Conclusions Recommendations Statements of study Objectives of study Rationale of the study Methodology of study and major findings on Specific objective 1 Specific objective 2 Specific objective 3 Conclusions Recommendations 2

Statements of study More evidences of climate change and its impacts are coming forth as an challenge to human sustainability Adopting the low carbon technologies, low carbon fuels, and clean energy resources are the options to promote low carbon economy Individual, institutional, and community level efforts towards low carbon society are necessary to reduce global emissions AIT, promoting as a green institution needs to assess the locally available renewable energy resources with its potential applications to replace the existing fossil fuels consumption The woody biomass wastes are one of the prominent sources of energy which is being collected and dumped without its potential utilizations in AIT 3

Objectives of the study Overall Objective A. To investigate the woody biomass potentials at AIT and its usage in thermal and electrical applications Specific Objectives 1. To estimate the woody biomass potential in AIT and its characterization 2. To develop and test two stage air supply biomass downdraft gasifier and gasifier engine with heat recovery system 3. To estimate the possible GHG emissions reduction opportunities using potential woody biomass to promote low carbon campus 4

Rationale of study Woody biomass potential at AIT would be known in terms of theoretical biomass potential, technical biomass potential and technical energy potential to add energy value to waste biomass materials The best operational air supply combination for long two stage air supply gasifier would be determined to get maximum heating value of producer gas The heat recovery opportunity from producer gas would be studied Potential areas to utilize available biomass source would be determined and analyzed GHG emissions reduction opportunity to promote low carbon campus 5

Methodology of study and Results & discussions Specific objective 1 Specific objective 2 Specific objective 3 6

Specific objective: 1- Methodology Methodology of study Theoretical Biomass Potential Technical Biomass Potential Technical Energy Potential Characterization of woody biomass Moisture content variation after different period of time 7

Monthly variation of potential of woody biomass (as received) 8 Total biomass potential with uncertainty of measurement 3.47% Potential of dry and wet tree branches with uncertainty of measurement 4.17%

Quantification of woody biomass energy 9

Specific Objective: 2 Methodology 10 Framework of experimental set up Biomass gasifier engine energy conversion system with heat recovery

Experimental set up 11 Two stage air supply downdraft gasifier Diesel engine Heat exchanger

Experimental works 12 1. Two stage air supply gasifier operation with primary and secondary air inlet including heat exchanger 2. Operation of diesel engine with diesel fuel as single fuel mode 3. Operation of diesel engine with duel fuel mode with producer gas 4. Thermal application of woody biomass waste from AIT 5. Thermal and electrical application of woody biomass waste from AIT To obtain the characteristics of gasifier and the best air supply combination on primary and secondary air supply To determine increased efficiency of gasification due to HE To obtain the characteristics of gasifier and the best air supply combination on primary and secondary air supply To determine increased efficiency of gasification due to HE To obtain the operational characteristic of diesel engine such as diesel consumption, exhaust gas composition, operating efficiency of engine etc.. To obtain the operation characteristic of diesel engine in dual fuel mode and compared with single fuel mode (diesel only), keeping air flow to gasifier at 100 LPM on both ports To determine increased efficiency of gasifier engine system due to HE To obtain the operation characteristic of diesel engine in dual fuel mode and compared with single fuel mode (diesel only), keeping air flow to gasifier at 100 LPM on both ports To determine increased efficiency of gasifier engine system due to HE To obtain average the producer gas flow rate, its heating values, and efficiencies To obtain overall thermal application possibilities To obtain average the producer gas flow rate, its heating values, and efficiencies To obtain overall thermal application possibilities To obtain the characteristics of gasifier engine system with heat recovery for electrical and thermal applications To obtain overall thermal and electrical applications possibilities To obtain the characteristics of gasifier engine system with heat recovery for electrical and thermal applications To obtain overall thermal and electrical applications possibilities Eucalyptus wood Woody biomass at AIT

Gas composition & LHVs of gas variation with air supply 13 The gas composition & heating values depend on air flow combination at PAS, & SAS The average heating value of producer gas is 4.5MJ/Nm 3 The best combination of air flow was observed at PAS (100 LPM) and SAS (80 LPM) Uncertainty 0.082 MJ/Nm 3 Gasifier system: Eucalyptus wood Gas composition LHVs of producer gas

Share of energy input in engine 14 Gasifier engine system: Eucalyptus wood Producer gas energy share of 40 70 % with diesel saving of 0.18 0.42 ml/s 5 6 kW e

Sankey diagram: Gasifier system 15 Gasifier without heat recovery Gasifier with heat recovery 14 % of total heat content of producer gas or 2 % of total power input Gasifier system: woody biomass at AIT

Sankey diagram: Gasifier engine system 16 Gasifier engine system: woody biomass at AIT

Specific Objective 3: Methodology 17 Gasifier system Gasifier engine system GHG emissions reduction by generated electricity, thermal energy, and saved diesel from the system were calculated

No emissions benefit by replacing natural gas based electricity in Thailand CO 2 emissions reduction opportunities 18 Energy/fuel/GHGsGasifier system Gasifier engine system Thermal energy (GJ/year)63430 Electrical energy (kWh/year)-45,490 Cooking: LPG (only) Amount saved (kg/year) (thermal)13,399635 Amount saved (kg/year) (electrical)-9,892 Equivalent tCO 2 /year (thermal)401.896 Equivalent tCO 2 /year (electricity)-26 Heating: Fuel oil(only) Amount saved (kg/year)15,687744 Amount saved (kg/year) (electrical)-11,582 Equivalent tCO 2 /year (thermal)492.326 Equivalent tCO 2 /year (electricity)-26 Electricity: Natural gas (only) Amount of natural gas saved (kg/year) (thermal)13,204626 Amount of natural gas saved (kg/year) (electrical)-9748 Equivalent tCO 2 /year (thermal)361.686 Equivalent tCO 2 /year (electricity)-26 Benefits of dual fuel electricity generation Dual fuel emission (tCO 2 /year)-44 Diesel saved (kg/year)-6,866 Equivalent tCO 2 /year of saved diesel-23 Single fuel emission (tCO 2 /year) (producer gas mode)-67

Opportunities to be a low carbon campus: Thermal application 19 LPG consumptions can be replaced by thermal energy from gasifier system in each of sectors but AITCC will be the best option as the excess energy can also be used to replace fuel oil or LPG with more emissions reduction and money saving opportunity: Promoting low carbon hotel as a part of low carbon campus 84 tonnes CO 2 emissions in 2010

Conclusions Theoretical biomass potential, technical biomass potential, and technical energy potential of woody biomass were found 1,596 kg /day 238 kg per day, and 4.07 GJ/day The highest heating value of producer gas (LHV 4.72 MJ/Nm 3 and HHV 5.10 MJ/Nm 3 ) was observed at PAS (100 LPM) and SAS 80 (LPM) The overall gasifier engine system efficiency of was 13.86% at electrical load of 10.54 kW e with diesel saving of 0.42 ml/s The best possible option to install the gasifier system is AITCC to promote low carbon hotel as the producer gas energy of 634 GJ per year can be utilized for both cooking and heating water with emissions reduction and financial benefits opportunities of 41,944 kg CO 2 and 428, 406 Baht per year 20

Recommendations for further studies Study on gasifier engine system with thermal heat recovery at engine exhaust gas can be carried out to use recovered heat a as heat medium in vapor absorption cycle to develop small scale renewable energy based cogeneration (power and cooling) system. The longer reactor in gasifier may have higher temperature drop along the reactor and cause deficiency of thermal energy for reduction reactions. It results low CO values in producer gas. Therefore, study can be carried out to optimize and locate the best position of air supply in such long reactor by varying air supply port. The study can be done to design and install gasifier system for thermal applications in AITCC to replace LPG and fuel oil to promote low carbon hotel as an option for low carbon campus 21

Thank you for your kind attention!!! 22 Queries ???

Scopes and limitations of the study Specific objective 1 Determination of woody biomass potential limited to availability of biomass tree residues (dry wood branches, fresh tree branches, fresh tree leaves, dry leaves, and grasses in AIT premises) Characterizations of woody biomass will be based on its heating values and proximate analysis The theoretical & technical biomass potential, and technical biomass energy potential will be determined 23

Scopes and limitations of the study (Cond.) Specific objective 2 Biomass downdraft two stage air supply gasifier with heat recovery and gasifier engine system will be developed and tested using Eucalyptus wood and woody biomass from AIT The Eucalyptus wood based tests are limited to their performance study of systems whereas the tests using the woody biomass from AIT are to investigate potential thermal and electrical energy generation Specific objective 3 Total CO 2 emissions reduction potential from available producer gas will be investigated Study on replacement of LPG, and fuel oil used for cooking and heating water at AIT will be carried out to reduce stationary combustion based emissions as a option for Low carbon campus Pre feasibility study of different energy systems for available producer gas will be carried out to estimate CO 2 emissions reduction potential by using RETScreen 24

Collection of woody biomass waste The collection and management of woody biomass waste at AIT is responsible to Decoration and Cleaning (DC)unit of Sodexo, AIT The quantification of such collected biomass is carried out by counting number of trucks thrown in the dumping side Each trucks has a capacity of loading around 100 kgs 25 DC unit, Sodexo Zonal division for cleaning and decoration of AIT (12 zones) Collection Loaded on truck Dumping area 100 kg per truck Record data: Number of truck dumped/week

Variation of moisture content Moisture content is the major factor to be studied to identify, select, and implement any biomass conversion energy system 26 November December

Theoretical potential of woody biomass (as received) 27

Characterization of woody biomass 28

Comparison of experimental and with estimated HHVs values 29

Correlation development for estimating higher heating values based on proximate analysis: novel approach HHVs of biomass are very important parameter for analysis of any bio-energy system Cussion bomb calorimeter/ TGA methods are used to find heating values experimentally, However, the experimental methods are complex, time consuming, and need high level skills to conduct experiment, Many correlations have been developed for various solid fuels and present the relations based on the linear and non linear effect of proximate components Therefore, this study developed the correlations to find HHVs for biomass based on the effect of ratio of different proximate values 30

Proposed correlations S.N.Proposed relation (on dry basis) 1HHV = a + b FC/VM 2HHV = a + b VM/FC 3HHV = a + b FC/Ash 4HHV = a + b Ash/FC 5HHV = a + b VM/Ash 6HHV = a +b Ash/VM 7HHV = a + b FC/VM + c VM/FC 8HHV = a + b VM/Ash + c Ash/VM 9HHV = a + b FC/Ash + c Ash/FC 10HHV = a+ b FC/VM + c VM/Ash 11HHV = a+ b VM/Ash +c Ash/FC 12HHV = a+ b Ash/FC + c FC/VM 13HHV = a+ b VM/FC + c Ash/VM 14HHV = a+ b Ash/VM + c FC/Ash 15HHV = a+ b FC/Ash+ c VM/FC 16HHV = a+ b FC/VM + c VM/Ash +d Ash/FC 17HHV = a+ b VM/FC + c Ash/VM + d FC/Ash 18HHV = a+ b (FC+VM)/Ash 19HHV = a+ b (FC + Ash)/VM 20HHV = a+ b (Ash + VM)/FC 31 250 published data of proximate analysis and validation & comparative study using 10 experimentally determined values Case 1: Linear relations (5.63 23.459 MJ/kg ) Case 2: Non linear relations of selected relation from case 1 Principle of correlation development: Least sum square error Error e = E M Determination of constant coefficients are based on least value of sum of e 2 for 250 data Microsoft Excel: Solver Tool

Forecasting error and selection 32 Low AAE indicates the less error in forecasting whereas the more positive value of ABE represents overestimation and more negative is indication of underestimation compared to experimental values. Therefore, the relation with less AAE and ABE closed to zero is selected as the best option The mean absolute error gives the possible error in forecasted values in term of MJ/kg The values MAE, AAE, and ABE for linear and non linear correlations were found 1.31 MJ/kg, 8.67 % & 1.55% and 0.98 MJ/kg, 5.85%, & 0.80 respectively

Major findings of objective 1 Moisture contents of woody biomass were found approx. up to 80% The total theoretical biomass potential = 47.877 tonnes/month Technical potential of woody biomass = 7.136 tonnes/month (THBP current usage removed moisture in 10 days) Total energy potential from woody biomass = 122.158 GJ/month (Notes: It is assumed that ratio of dry and wet sticks are 20 and 80 % of total woody biomass) (HHVs were determined by averaging the values of two analyzed months: for dry and fresh branches in November and December) 33

Apparatus and materials 34 Two stage air supply gasifier Heat exchanger ParticularsSize NamePerkin Diesel Engine No. of cylinders3 Orientation of cylinders Vertical Bore Stroke91.4127 mm Compression ratio18.5:1 Combustion typeDirect injection Maximum revolution 2300 RPM Maximum power36.6 kW Fuel capacity2.5 liter Diesel engine specification

Apparatus and materials 35 Cyclone separator Water sprayer

Apparatus and materials 36 On line gas analyzerTar measurement units

Apparatus and materials 37 Raw materials Woody biomass at AIT (2 2 2 cm) Properties ( % by weight on wet basis) Eucalyptus wood Woody biomass at AIT Moisture content, % 10.17 9.43 Ash content, %0.75 0.73 Volatile matter, %74.25 74.74 Fixed carbon, %14.84 15.09 Higher heating value, MJ/kg 18.50 18.39 Proximate analysis Ultimate analysis Element ( % by wt dry basis) Eucalyptus wood b Woody biomass at AIT b Carbon, C 45.12 43.89 Hydrogen, H 4.62 5.38 Oxygen, O 50.26 40.17 Nitrogen, N 0.00 - Sulfur, S 0.00 - a Sompop (2008), b Correlation based O=100 C H N S Eucalyptus wood (2 2 2 cm)

Installation of heat exchanger 38 Inner structure Installation Completion of installation Under test

Temperature distribution along gasifier 39 Gasifier system

Variation of producer gas composition 40 Effect of total air supply Gas composition depends on different combination of air flow Effect of secondary air supply variation More CO at higher secondary air flow Gasifier system

Tar content of producer gas The tar content is important factor to be considered for engine applications (< 100 mg/Nm 3, Source: Basu, 2010) The cleaning and cooling of producer gas was done by using cyclone separator and water sprayer (< 45 0 C) to make suitable for engine applications The tar was measured at outlet of water sprayer No tar was observed in the producer gas 0.318 m 3 gas flow in 3 hrs of operation However, it observed negligible condensate on collector tank on next day 41 Gasifier system

Performance of heat exchanger The average effectiveness of heat exchanger was observed 0.62 Maximum heat recovered was found 1.465 kW 42 SN Air supply Produc er gas Water flow Temperature, 0 C Effectivene ss LPMkg/hr Gas_ in T Gas_ out T W_ inT W_ outT e = q/q max 114014.3036.94306.999.231.247.00.62 216016.3431.57315.6108.331.354.00.64 318015.9730.80342.2122.630.856.20.66 420018.5838.19360.6131.430.355.30.60 522018.3337.54366.8141.433.851.70.59 624019.2234.15371.1141.232.053.00.61

Impact of heat recovery Gasifier system 43 Gasifier system: Cold gas efficiency (increases around 2 -4 %) Heat recovery system

Impact of heat recovery: Gasifier engine system 44 Gasifier engine system: Overall gasifier engine system (Less than 3%) Decreasing trend of % increased in efficiency with higher electrical load increased in efficiency Heat recovery system

Diesel fuel consumption and fuel saving 45 Equal share of producer gas and diesel energy input Gasifier engine system

Efficiencies of system 46 Brake thermal efficiency Engine generator efficiency 8.1% Overall gasifier engine efficiency 6.04 % Single: 25.26% Dual: 22.19% Single: 21.47% Dual: 19.02% 13.86 % (PS) 11.69% at 11.14 kW e (Hla, 1999) Gasifier engine system

Specific energy consumption: CI engine power generation system 47 Higher energy consumption due to low engine efficiency at part load condition Gasifier engine system

Engine exhaust gas composition 48 Fraction of producer gas composition was observed in engine exhaust and decreases at higher engine loads Comparison CO 2 emissions between single and dual fuel mode of engine operation Gasifier engine system

Exhaust gas temperature and heat loss 49 Exhaust gas temperatures are larger in dual fuel mode Thermal power loss from exhaust gas Gasifier engine system Single and Dual fuel mode

CO 2 emissions and emission intensity of gasifier engine system 50 CO 2 emissions CO 2 emissions intensity

Experimental results of gasifier and gasifier engine system using woody biomass at AIT 51 ParametersValues Producer gas yield, Nm 3 /kg14.45 LHV of gas, Nm 3 /hr4.13 Operating power, kW e 5.85 Diesel fuel consumption, kg/hr1.47 Exhaust gas temperature, 0 C289.27 Engine generator efficiency, %14.75 Gasifier engine efficiency, %9.33 Share of producer gas (16.57 kW), %43.37 Heat recover (HE), kW0.87 Effectiveness of heat exchanger, e0.63 Overall gasifier engine efficiency with HE, %10.71 % increased in efficiency by HE, %14.82 Gasifier system Gasifier engine system Woody biomass at AIT

Linear extrapolation of results 52 Parameters Gasifier systemGasifier engine system Experimented values Air supply rate (LPM)100, 80 (180) Producer gas flow rate (Nm 3 /hr)14.8614.45 Producer gas yield (Nm 3 /kg of feedstock)1.871.8 Biomass consumption (kg/hr)7.958.04 Lower heating values (MJ/Nm 3 )4.24.1 Higher heating values (MJ/Nm 3 )4.54.4 Thermal power (kW)17.34- Electrical power (kW)-5.85 Hot water (kW)0.810.87 Share of producer gas (%)-43.37 Diesel consumption (ml/s)-0.57 Diesel saving (ml/s)-0.292 Total thermal energy per month (MJ/month)42,3402030 Total electrical energy per month (MJ/month)-13,647 Total biomass available (kg/hr)9.92 Linear extrapolation Producer gas flow (Nm 3 /hr)18.5417.86 Thermal power (kW)21.63- Electrical power (kW)-5.85 Hot water (kW)1.011.07 Share of producer gas (%)-53.51 Diesel saving (ml/s)-0.360 Total thermal energy per month (MJ/month)52,8142,504 Total electrical energy per month (kWh/month)-3,791 Total thermal energy per year (GJ/year)634498

Ideal CO 2 emissions reduction opportunity: (Energy equivalent) 53 5.15% of total AIT emission (14,895 tCO 2 /year) 4.2 % of total

Fossil fuels consumption at AIT 54 Monthly LPG consumptions in residential areas Monthly fuel oil and LPG consumptions for cooking and heating purpose in commercial sectors at AIT Total LPG based Energy = 822 GJ/yr Total Fuel oil based Energy = 412 GJ/yr Total stationary combustion based CO 2 emission of 84 tonnes / year Total fossil based Energy = 1234 GJ/yr

Base load electricity demand in AIT 55 Average base load were determined by using electricity consumption (kWh), reported by Autchara (2010) Approx. 19 kW e Approx. 10- 12 kW e

56 Design of electricity generation system based on electrical load demand Exceeded Electrical load demand at different field of studies cannot be satisfied by single fuel producer gas engine system

57 Pre-feasibility study using RETScreen ParametersValuesUnits Common terms Equivalent full load hours90% Based case fuelDiesel Fuel cost (diesel)0.99$/liter Electricity cost0.1$/kWh Proposed case fuelProducer gas Producer gas (CO, CH 4, CO 2, H 2 ) (16.4, 1.5, 14.4, 12.9) % by Vol. Temperature of producer gas37C Heating values of gas3.823MJ/m 3 Inflation rate3.5% Project life20years Annual O & M cost 1,200 (100 12) $ Debt ratio0% Based case electricity generation fuel Natural gas Climate locationBangkok Peak process heating load3kW Gross electrical load5kW Heat rate of reciprocating engine14MJ/kWh Heat recovery efficiency50% Initial installation cost2,100$/kW ResultsValuesUnits Base case annual diesel consumption3,413Liters Total heating energy24MWh Annual electricity energy44MWh Heating capacity from heat recovery7.2kW Energy from fuel required0.1GJ/hr Heating values of gas3,823MJ/m 3 Fuel required for power144,342m 3 /year Fuel required for heating 3,426 m 3 /year Net annual GHGs reduction31t-CO 2 Annual gasoline not used12,596Liters Initial cost10,500$ Annual O & M cost1,200$ Annual saving cost7,759$ Pre tax IRR63.8% Simple payback period1.7Years Case I: Cogeneration using producer gas (Heating and Power) Limiting constraints: 162,447 m 3 /yr

ParametersValuesUnits Base case annual fuel consumption 6,826Liters Total heating energy47MWh Annual electricity energy61MWh Heating capacity from heat recovery 18kW Energy from fuel required0.2GJ/hr Share of producer gas150,322m 3 /year Share of diesel18,303Liter Net annual GHGs reduction8.4t-CO 2 Annual gasoline not used3,433Liters Initial cost18,900$ Annual O & M cost19,934$ Annual saving cost12,890$ Pre tax IRRnegative% Simple payback periodNAYears 58 Pre-feasibility study using RETScreen Case II: Cogeneration dual fuel mode (Heating and Power) Limiting constraints: 162,447 m 3 /yr ParametersValuesUnits Common terms Equivalent full load hours90% Based case fuelDiesel Fuel cost (diesel)0.99$/liter Electricity cost0.1$/kWh Proposed case fuelProducer gas Producer gas (CO, CH 4, CO 2, H 2 ) (16.4, 1.5, 14.4, 12.9) % by Vol. Temperature of producer gas37C Heating values of gas3.823MJ/m 3 Inflation rate3.5% Project life20years Annual O & M cost1,200 (100 12)$ Debt ratio0% Based case electricity generation fuel Natural gas Climate locationBangkok Peak process heating load6kW Gross electrical load7kW Heat rate of reciprocating engine18MJ/kWh Heat recovery efficiency50% Share of diesel fuel55% Share of producer gas45% Reciprocating engine capacity9kW Initial installation cost2,100$/kW

Input and outputValuesUnits Base case fuel- propane (LPG)17,384kg/year Annual fuel cost11,010$/year Annual producer gas available146,202m 3 /year Initial incremental costs7000 (350*20)$ Annual maintenance cost600 (5012)$ Pre tax IRR157.4% Simple payback period0.7Years Net annual GHGs reduction52.3t-CO 2 59 Pre-feasibility study using RETScreen Case III: LPG - producer gas: replacement Case III: LPG - producer gas: replacement

Conclusions (Cond.) Up to 1.47 kW of hot water was recovered with average percentage increased in cold gas efficiency of 5.23 % whereas the percentage increased in overall gasifier engine system efficiency varied with electrical power output 84 tonnes of CO 2 emissions caused by LPG and fossil fuel consumption at AIT in 2010 can be reduced by approximately 46.23% with respect to overall thermal energy from producer gas, considering conversion efficiency of 90% Electricity using gasifier engine system can satisfy the base loads of various field of studies saving grid based electricity. However, dual fuel mode electricity has more emissions than natural gas based grid electricity though it saves primary energy 60

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