Biomass Gasification presentation

BIOMASS GASIFICATION

BIOMASS GASIFICATIONGroup Members:Pritish ShardulMohit Meena

Guide: Mr. Ganesh Kale, Senior Scientist, NCL, Pune

IntroductionGasificationis a process that convertsorganic or fossilbased carbonaceous materials mainly intocarbon monoxide, hydrogenand carbon dioxideToday there is a huge demand for fuel because of the increasing population. Biomass is renewable resource and is available very easily. It is the third among the primary energy sources after coal and oilThe gasification of biomass allows the production of a synthesis gas or syngas, consisting primarily of H2, CO, CH4, CO2 and N2, which further has a variety of uses

IntroductionA thermodynamic analysis of the process of biomass gasification was conducted to find the Thermoneutral Points (TNPs) for different gasifying agents for different compositions of the input streams to the gasifierReaction TNPs (R-TNPs), Process TNPs (P-TNPs) with and without Heat Exchanger were calculated and product gas compositions at TNPs were analysed for syngas production, syngas ratio, %CO2 conversion and heat utilities during the course of this study

IntroductionIt is assumed that the exit products of the coal gasifier are in thermodynamic equilibrium.HSC Chemistry software is well known software that uses the Gibbs free energy minimization algorithm to find the equilibrium product composition from a feed mixture and has been used in gasification studies earlier[Kumabe K, Hanaoka T, Fujimoto S, Minowa T, Sakanishi K. Co-gasification of woody biomass and coal with air and steam. Fuel 2007;86:6849.]We have also used HSC Chemistry 5.11 for our calculations

Literature SurveyWe downloaded many abstracts and shortlisted around 80 relevant abstractsWe sorted out the shortlisted abstracts in the following divisions- Thermodynamic Analysis- Experimental- Modelling- Reviews- Theoretical

Biomass SelectionWe chose Rice husk as the biomass to be gasified.Composition by weight: 47.8% C, 5.1% H, 38.9% O, 0.1% N(Ref : Jenkins, B.M. & Ebeling, J.M, Correlation of physical & chemical properties of terrestrial biomass with conversion, symposium, Energy from biomass & waste, Pg no-371)Weight for 1 mole of rice husk is calculated to be 25.105 gramsWe calculated the compositions in moles for one mole of carbon in biomass as follows,For 1 mole carbon, 0.6402 moles of H2, 0.3052 moles O2, 0.0008 moles N2Temperature range considered in this study is 500-1000 C

MethodologyPART A : R-TNP AnalysisFor a particular feed condition, we calculated the output composition of the reactor using 'Equilibrium Compositions' module of HSC Chemistry 5.11 at temperatures ranging from 500 to 1000 C, with intervals of 50 C and constant pressure of 1 bar

Using those compositions and 'Reaction Equations' module of HSC Chemistry 5.11, we calculated the reaction enthalpy at respective temperatures

Methodology (cont.)PART A : R-TNP AnalysisBy plotting the graph of Enthalpy vs. Temperature we calculated the R-TNP's of the reaction

We calculated the product gas compositions at the R-TNP's and analysed the parameters: Syngas, Syngas Ratio, %CO2 Conversion, Heat utility (without HE), Reduced Heat Utility (with HE)

1. Gasifying Agent: CO2We defined the parameter CCBR (CO2 to Carbon in biomass molar ratio)We varied CCBR in the input of the gasifier. Values of CCBR are: 0, 0.5, 1, 1.5, 2, 2.5, 3, 4, 5From the graphs of enthalpy change vs. temperature for all the CCBR, we found that thermoneutral points (TNPs) can be obtained for all the CCBR considered except 0 and 0.5 Thermoneutral temperature decreased with increase of CCBR

Reaction TNPs

Reaction TNPs

CCBRR-TNPoCCO2(g)molesCO(g)molesH2O(g)molesH2(g)molesCH4(g)molesN2(g) molesCmoles1728.48310.49891.49240.12030.50240.00870.000801.5688.10060.96061.5180.17070.44950.00990.00080.01152665.29041.43241.5380.20760.41360.00950.00080.02022.5648.50941.91141.55120.2360.38610.00890.00080.02853635.37412.39381.56360.25880.36450.00840.00080.03424615.22673.36781.58090.29390.33150.00740.00080.043956004.34891.59210.32020.30660.00660.00080.0524

Reaction TNPs

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CCBRR-TNPoCSyngas(moles)SyngasRatio% CO2Conversion1728.48311.994820.33665250.1151.5688.10061.967470.29609435.95732665.29041.951620.26893428.382.5648.50941.937330.24892323.5443635.37411.928090.23310920.20674615.22671.912350.20965915.80556001.89870.19257613.022

Reaction TNPs

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Gasifying Agent: CO2 - TrendsSyngas, Syngas Ratio and % CO2 conversion decreased with increase in CCBRHeat utility (without HE) increased linearly with increase in CCBRHowever, Heat utility (with HE) decreased then remained constant with the increase of CCBR

Reaction TNPs

Reaction TNPs

Reaction TNPs

Configuration (Heat Utility) without Heat Exchanger

Heat Utility at Reaction TNPs

Configuration (Reduced Heat Utility) with Heat Exchanger

Heat Utility at Reaction TNPs

2. Gasifying Agent: H2OWe defined the parameter HCBR (H2O to Carbon in biomass molar ratio)We varied HCBR in the in the input of the gasifier. Values of HCBR are: 0, 1, 2, 3, 4From the graphs of enthalpy change vs. temperature for all the HCBR, we found that no thermoneutral points can be obtained for any of the HCBR considered

Reaction TNPs

3. Gasifying Agent: CO2 & H2OWe defined the parameter GaCR (Gasifying Agents to Carbon in Biomass molar ratio)We varied GaCR from 1 to 4 in the input of gasifier and considered different combinations of CCBR and HCBR for each GaCRFor GaCR = 1, R-TNPs were obtained only for 1/0For GaCR = 2, P-TNPs were obtained only for 2/0For GaCR = 3, P-TNPs were obtained for 3/0, 2.5/0.5For GaCR = 4, P-TNPs were obtained for all combinations which had CCBR greater than or equal to 3

Reaction TNPs at GaCR = 1




GaCRCCBR/HCBRTNPoCCO2(g)molesCO(g)molesH2O(g)molesH2(g)molesCH4(g)molesN2(g) molesCmoles11/0728.4830.49891.49240.12030.50240.00870.001022/0665.2901.43241.5380.20760.41360.00950.0010.020133/0635.3742.39381.56360.25880.36450.00840.0010.034232.5/0.5718.7302.05041.44850.56120.57670.00110.001044/0615.2273.36781.58090.29400.33150.00740.0010.043943.75/0.25612.9653.22571.50540.40320.45770.01450.0010.004443.5/0.5647.9933.04121.45330.57430.55470.00550.001043.25/0.75728.6112.80311.44650.80770.58160.00040.001043/1858.2852.52391.47611.08650.55370.000010.0010

Reaction TNPs

GaCRCCBR/HCBRTNPoCSyngas(moles)SyngasRatio% CO2Conversion11/0728.4831.994820.33665250.11522/0665.2901.951620.26893428.3833/0635.3741.928090.23310920.2066732.5/0.5718.7302.02520.39813617.98444/0615.2271.912350.20965915.80543.75/0.25612.9651.963140.30406513.9813343.5/0.5647.9932.008040.38171113.1085743.25/0.75728.6112.028110.40208113.7507743/1858.2852.02980.3751115.87

Reaction TNPs

GaCR = 4 - TrendsR-TNP first slightly decreased with HCBR then increasedSyngas increased (from 1.9124 to 2.0298 moles per moles of Biomass) with increase in HCBRSyngas ratio showed a maxima (of 0.403) at HCBR = 0.714% CO2 conversion first decreased then increased with increase in HCBRHeat utility (with HE) increased with increase in HCBRHowever, Heat utility (without HE) first decreased slightly and the increased with increase in HCBR







MethodologyPART B: Process TNP Analysis (without HE) We calculated the Biomass preheating value for temperatures between 500 to 1000 C, with intervals of 50 C. Cp value of Rice husk was taken as 2.094 J/gK [Kaupp (1984)]We then calculated the preheating value of gasifying agents (CO2 and H2O) for respective temperatures. Cp value of CO2 and H2O was taken from Perry's Chemical Engineers' Handbook 7eWe then calculated the Process enthalpy (without Heat Exchanger) as the sum of Reaction enthalpy, Biomass preheating and Gasifying Agents preheating(Figure 1)

Configuration (Heat Utility) without Heat Exchanger

Methodology (cont.)PART B: Process TNP Analysis (without HE)We plotted the graph of Process enthalpy without heat exchanger vs. Temperature and calculated the P-TNP's without HE

We calculated the product gas compositions at the P-TNP's and analysed the parameters: Syngas, Syngas Ratio, %CO2 Conversion, Reaction Enthalpy at P-TNP's

1. Gasifying Agent: CO2We varied CCBR in the input of gasifier from 0 to 5

From the graphs of enthalpy change vs. temperature for all the CCBR, we found that TNPs can be obtained for all the CCBR except 0 and 5

Process TNPs without Heat Exchanger

CCBRTNPoCCO2(g)molesCO(g)molesH2O(g)molesH2(g)molesCH4(g)molesN2(g) molesCmoles0.5714.9310.30810.87680.11710.49270.01510.0010.31655.6050.79930.80630.2050.40240.01630.0010.37811.5619.5461.31190.72020.2660.34260.01570.0010.45222591.7311.8320.63270.31340.2970.01480.0010.52052.5568.2572.35420.54920.35240.25970.01390.0010.58273547.1932.87710.46970.3860.22780.01310.0010.644509.4523.91890.33030.4420.17480.01160.0010.7393


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CCBRTNPoCSyngas(moles)SyngasRatio% CO2Conversion0.5714.9311.36950.5619338.381655.6051.20870.4990720.071.5619.5461.06280.47570112.542591.7310.92970.4694178.42.5568.2570.80890.472875.8323547.1930.69750.484994.09664509.4520.50510.5292162.0275


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Gasifying Agent: CO2 - TrendsP-TNPs, Syngas and %CO2 conversion decreased with increase in CCBRSyngas Ratio showed a minima (of 0.469) at CCBR =2.056Reaction Enthalpy at P-TNPs was calculated and it showed a decrease with increase in CCBR






2. Gasifying Agent: H2OWe varied HCBR from 0 to 4 in the input of gasifier

From the graphs of enthalpy change vs. temperature for all the HCBR, we found that TNP can be obtained only for HCBR = 1, in the range of 500-1000 CHCBRTNPoCCO2(g)molesCO(g)molesH2O(g)molesH2(g)molesCH4(g)molesN2(g) molesCmolesSyngasmolesSyngasRatio% CO2Conv.1580.0120.43410.21640.52540.77040.17210.0010.17750.98683.5647.46


3. Gasifying Agent: CO2 & H2OWe varied GaCR from 1 to 4 in the input of gasifier

For GaCR = 1, P-TNPs were obtained for all the combinations of CCBR and HCBR consideredFor GaCR = 2, P-TNPs were obtained for three combinations 2/0, 1.5/0.5, 1/1For GaCR = 3, P-TNPs were obtained for two combinations 3/0, 2.5/0.5For GaCR =4, only 1 P-TNP was obtained for 4/0

Process TNPs at GaCR = 1




GaCRCCBR/HCBRTNPoCCO2(g)molesCO(g)molesH2O(g)molesH2(g)molesCH4(g)molesN2(g) molesCmoles11/0655.6050.79930.80630.2050.40240.01630.0010.378110.5/0.5623.69800.63110.47790.36990.64280.06360.00100.327410/1580.0120.43410.21640.52540.77040.17210.0010.177522/0591.7311.8320.63270.31340.2970.01480.0010.520521.5/0.5560.2561.58020.37080.57870.45120.05510.0010.493821/1518.7731.28830.17260.86080.50590.13660.0010.402533/0547.1932.87710.46970.3860.22780.01310.0010.6432.5/0.5514.0182.56690.25870.71740.32830.04710.0010.627244/0509.4523.91890.33030.4420.17480.01160.0010.7393


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GaCRCCBR/HCBRTNPoCSyngas(moles)SyngasRatio% CO2Conversion11/0655.6051.20870.4990720.0710.5/0.5623.69801.12071.345051-26.2210/1580.0120.98683.560074-22/0591.7310.92970.4694178.421.5/0.5560.2560.8221.216828-5.3466721/1518.7730.67852.931054-28.8333/0547.1930.69750.484994.09666732.5/0.5514.0180.5871.269037-2.67644/0509.4520.50510.5292162.0275


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Gasifying Agent: Both -TrendsP-TNPs and Syngas production decreased with increase in HCBR for both GaCR 1 and 2Syngas ratio showed an increase with increase in HCBR for both the GaCRReaction enthalpy at P-TNPs decreased with increase in HCBR

Process TNPs without HE at GaCR = 1 & 2




MethodologyPART C: Process TNP Analysis (with HE)We calculated the Product Gas Cooling Energy released at respective temperature. Product gas consisted of CO2(g), CO(g), C, H2O(g), H2(g), CH4(g) and N2(g). Cp values of all the components were taken from Perry's Chemical Engineers' Handbook 7eWe then calculated the Process enthalpy (with Heat Exchanger) as the sum of Reaction enthalpy, Biomass preheating, Gasifying Agents preheating + Product Gas Cooling (Figure 2)

Configuration (Reduced Heat Utility) with Heat Exchanger

Methodology (cont.)PART C: Process TNP Analysis (with HE)We plotted the graph of Process enthalpy with heat exchanger vs. Temperature and calculated the P-TNP's with HE We calculated the product gas compositions at the P-TNP's and analysed the parameters: Syngas, Syngas Ratio, %CO2 Conversion, Reaction Enthalpy at P-TNP's

1. Gasifying Agent: CO2We varied CCBR in the input of gasifier from 0 to 5

From the graphs of enthalpy change vs. temperature for all the CCBR, we found that TNPs can be obtained for all the CCBR except 0

Process TNPs with Heat Exchanger

CCBRTNPoCCO2(g)molesCO(g)molesH2O(g)molesH2(g)molesCH4(g)molesN2(g) molesCmoles0.5812.2390.10061.36650.04230.58380.00690.0010.0261720.6740.51931.44810.12340.49650.01010.0010.02261.5686.3570.97151.4940.1730.44690.010.0010.02452664.591.43741.52670.20860.41240.00950.0010.02642.5648.3851.91241.5490.23620.38590.00890.0010.02973635.5222.39261.56630.25850.36470.00840.0010.03274615.7143.36311.59070.29310.33210.00740.0010.03885600.674.34231.60630.31910.30770.00660.0010.0448


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CCBRTNPoCSyngas(moles)SyngasRatio% CO2Conversion0.5812.2391.95030.42722379.881720.6741.94460.34286348.071.5686.3571.94090.2991335.23332664.591.93910.27012528.132.5648.3851.93490.24912823.5043635.5221.9310.23284220.24664615.7141.92280.20877615.92255600.671.9140.19155813.154


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Gasifying Agent: CO2 - TrendsP-TNPs, Syngas production, Syngas ratio and % CO2 conversion decreased with increase in HCBRReaction enthalpy at R-TNPs increased and went from exothermic region to endothermic regionReaction enthalpy for CCBR = 2.68 was zero. Thus, R-TNP and P-TNP is same for CCBR 2.68






2. Gasifying Agent: H2OWe varied HCBR in the input of gasifier from 0 to 4

From the graphs of enthalpy change vs. temperature for all the HCBR, we found that TNPs can be obtained for all the HCBR except 0


HCBRTNPoCCO2(g)molesCO(g)molesH2O(g)molesH2(g)molesCH4(g)molesN2(g) molesCmoles1713.03300.29000.67880.35131.22620.03130.00100.00002651.6260.56810.39731.07651.49430.03460.00103611.4970.71610.24781.93011.63750.03620.00104581.2060.79820.16472.84891.71690.03710.0010

Process TNPs with Heat ExchangerHCBRTNPoCSyngas(moles)SyngasRatio% CO2Conversion1713.03301.9051.806423712651.6261.89163.76113871.5953611.4971.88536.60815276.134581.2061.881610.4244180.045

Gasifying Agent: H2O - TrendsP-TNPs and Syngas Production decreased with increase in HCBRSyngas ratio and % CO2 Conversion increased with increase in HCBRReaction enthalpy at P-TNPs decreased with increase in HCBR






3. Gasifying Agent: CO2 & H2OWe varied GaCR from 1 to 4 in the input of gasifier

For all the GaCR, P-TNPs were obtained for all the combinations of CCBR and HCBR considered

Process TNPs GaCR = 1

GaCRCCBR/HCBRTNPoCCO2(g)molesCO(g)molesH2O(g)molesH2(g)molesCH4(g)molesN2(g) molesCmoles11/0720.6740.51931.44810.12340.49650.01010.0010.022610.5/0.5709.5680.41551.05570.22340.85890.02880.001010/1713.03300.29000.67880.35131.22620.03130.00100.0000

Process TNPs with Heat Exchanger at GaCR = 1GaCRCCBR/HCBRTNPoCSyngas(moles)SyngasRatio% CO2Conversion11/0720.6741.94460.34286348.0710.5/0.5709.5681.91460.81358316.910/1713.03301.9051.806423-

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GaCRCCBR/HCBRTNPoCCO2(g)molesCO(g)molesH2O(g)molesH2(g)molesCH4(g)molesN2(g) molesCmoles22/0664.591.43741.52670.20860.41240.00950.0010.026421.5/0.5652.731.26541.20430.3750.70440.03030.001021/1659.9591.05030.91770.59170.98440.0320.001020.5/1.5659.8440.81780.6490.82541.24820.03320.001020/2651.6260.56810.39731.07651.49430.03460.0010

Process TNPs with Heat Exchanger at GaCR = 2GaCRCCBR/HCBRTNPoCSyngas(moles)SyngasRatio% CO2Conversion22/0664.591.93910.27012528.1321.5/0.5652.731.90870.58490415.6421/1659.9591.90211.072682-5.0320.5/1.5659.8441.89721.923267-63.5620/2651.6261.89163.761138-


GaCRCCBR/HCBRTNPoCCO2(g)molesCO(g)molesH2O(g)molesH2(g)molesCH4(g)molesN2(g) molesCmoles33/0635.5222.39261.56630.25850.36470.00840.0010.032732.5/0.5623.3462.1841.28070.46120.62170.02860.0010.006732/1627.5971.93111.03470.71310.85850.03420.001031.5/1.5630.181.65360.81130.99151.07820.03510.001031/2628.6761.35870.60571.2871.28170.03570.001030.5/2.5622.8461.04680.41711.59931.46850.03610.001030/3611.4970.71610.24781.93011.63750.03620.0010

Process TNPs with Heat Exchanger at GaCR = 3

GaCRCCBR/HCBRTNPoCSyngas(moles)SyngasRatio% CO2Conversion33/0635.5221.9310.23284220.2466732.5/0.5623.3461.90240.48543812.6432/1627.5971.89320.8297093.44531.5/1.5630.181.88951.328978-10.2431/2628.6761.88742.116064-35.8730.5/2.5622.8461.88563.520738-109.3630/3611.4971.88536.608152-



GaCRCCBR/HCBRTNPoCCO2(g)molesCO(g)molesH2O(g)molesH2(g)molesCH4(g)molesN2(g) molesCmoles44/0615.7143.36311.59070.29310.33210.00740.0010.038843.5/0.5605.1413.12711.33230.52350.56670.02490.0010.015843/1603.9922.8591.1040.7880.77810.0370.001042.5/1.5607.8812.55440.90821.0930.97220.03740.001042/2608.6112.23330.72921.41431.15070.03750.001041.5/2.5606.3341.89760.56451.75021.31410.03780.00104 1/3601.5611.54670.41542.10111.46320.03780.00104 0.5/3.5593.7881.18050.2822.4671.5980.03750.001040/4581.2060.79820.16472.84891.71690.03710.0010


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GaCRCCBR/HCBRTNPoCSyngas(moles)SyngasRatio% CO2Conversion44/0615.7141.92280.20877615.922543.5/0.5605.1411.8990.42535510.6542943/1603.9921.88210.7048014.742.5/1.5607.8811.88041.070469-2.17642/2608.6111.87991.578031-11.66541.5/2.5606.3341.87862.327901-26.506741/3601.5611.87863.522388-54.674 0.5/3.5593.7881.885.666667-136.140/4581.2061.881610.42441-



3. Gasifying Agent: Both - TrendsSyngas decreased with increase in HCBRSyngas ratio increased with increase in HCBR% CO2 conversion and Reaction enthalpy at P-TNPs decreased with increase in HCBR





ConclusionsSandeep et. al. varied SBR (Steam to Biomass Ratio) from 0.75 to 2.7. The hydrogen yield is found to be 104g/kg of biomass at SBR of 2.7. Significant enhancement in H2 yield is observed at higher SBR compared with lower range SBR REF: Sandeep, K., Dasappa, S., Oxysteam gasification of biomass for hydrogen rich syngas production using downdraft reactor configurationInternational Journal of Energy Research 2013In our study, for SBR = 3, hydrogen yield is found to be 130.45g/kg of biomass

ConclusionsExothermal regions were obtained in the biomass gasification with no oxygen in the input streamBiomass Gasification can be done auto thermally even without any input of external oxygen or airInbuilt oxygen content in biomass is large enough to carry out the gasification processThe product gas for some of the feed conditions can be used for Fischer Tropsch process in petroleum industries

GaCRCCBR/HCBRSyngas(moles)without HESyngasRatiowithout HESyngas(moles)with HESyngasRatiowith HE10/1--1.9051.80642321.5/0.50.8221.216828--21/10.67852.9310541.90211.07268220.5/1.5--1.89721.92326732.5/0.50.5871.269037--31.5/1.5--1.88951.32897831/2--1.88742.11606442.5/1.5--1.88041.07046942/2--1.87991.57803141.5/2.5--1.87862.327901

Syngas Ratio between 1 to 3For Fischer Tropsch

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Biomass Gasification presentation

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