Comparison of biomethane and syngas production as energy vectors for heat and power generation from palm residues: A

techno-economic, energy and environmental assessment

Juan Camilo Solarte Toro, Yessica Chacón Pérez, Carlos Ariel Cardona Alzatek

K.,Full professor of Chemical EngineeringInstituto de Biotecnología y Agroindustria

Departamento de Ingeniería QuímicaUniversidad Nacional de Colombia Sede Manizales1

o Introduction

o Objective

o Methodology

o Results

o Conclusions

o Acknowledgements

o References

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Research group on Chemical, Catalytic and Biotechnological Processes

Outline

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Research group on Chemical, Catalytic and Biotechnological Processes

Introduction: Energy demand and Oil-based economy

220

230

240

250

260

190

320

389

475

555

0 200 400 600

2000

2012

2020

2030

2040

Non-OECD OECD

US Quadrillon BTU

Figure 1. World energy consumption 2000 – 2040. (IEO, 2016)

3800

4000

4200

4400

4600

2012 2013 2014 2015 2016

Mill

ion

tonn

es

Oil consumption Oil production

Figure 2. Worldwide oil production and consumption (BP, 2017)

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Research group on Chemical, Catalytic and Biotechnological Processes

Introduction: Oil-based economy environmental effects

Environmental problemsOil-derived products

The obtained products from crude-oil and its derivatives have caused some environmental damages through greenhouse gases emissions, solid waste generation and natural resources pollution

Introduction: Energy security and Energy production5

Research group on Chemical, Catalytic and Biotechnological Processes

Figure 4. World net electricity generation by energy source includingHydropower (blue), IEO, 2016

The renewables use will increase in the next years to enhance the energy security of developed and non-developed countries

Energy SecurityEnergy Security

Affordable supply

AvailabilityReliable supply

Energy matrix diversification

Figure 3. Energy security concept

0

10

20

30

40

2012 2020 2025 2030 2035 2040

Trill

ion

kWh

Renewables Natural Gas Nuclear Coals

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Research group on Chemical, Catalytic and Biotechnological Processes

Introduction: Oil palm residues as renewable biomass in Colombia.

Figure 5. Oil palm crop in Colombia Figure 6. Biomass from oil palm crop

Colombia is the 5th worldwide producer of palm oil. However, a great amount of lignocellulosic residues are generated during its production.

Electricity

Heat

Chemicals

This work aims to compare from technical, economic, energy and

environmental perspective the heat and power generation using syngas

and biomethane as fuels produced from the gasification and anaerobic

digestion of the oil palm rachis produced in the central zone plantations

of Colombia.

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Research group on Chemical, Catalytic and Biotechnological Processes

Objective

• Proximate analysis

• Lignocellulosiccontent

Characterization of OPR

• Syngas production

• Biomethaneproduction

• Cogenerationsystem

Process design and simulation

• Thermal efficiency

• Net energy balance

Energy assessment

• CAPEX and OPEX

• CO2 emissions

Economic and environmental assessment

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Research group on Chemical, Catalytic and Biotechnological Processes

Methodology

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Research group on Chemical, Catalytic and Biotechnological Processes

Raw material characterization

Figure 7. Oil palm rachis (OPR)

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Chipper

Downdraftgasifier

AIR

SYNGASCleanning  system

CHAR, ASHES

OPR

Figure 8. Process flow diagram of of the OPR gasification using a downdraft gasifier

Research group on Chemical, Catalytic and Biotechnological Processes

Processes description: Syngas production

Reduction

C + CO2 2COC + H2O CO + H2

C + 2H2 CH4CH4 + H2O CO + 3H2CO + H2O CO2 + H2

Pyrolysis

C6H8.72O4.10 2.2C + 0.9CO2 + 0.64H2 + 2.2H2O + 0.002CH4 + 0.5TAR

Combustion

CH4 + 1.5O2 CO + 2H2O2CO + O2 2CO22H2 + O2 2H2O

TAR + 2.9O2 6CO + 3.1H2

ER = 0.5ER = 0.5

García et al. 2015.

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Milling

Grinding

OPR

AnaerobicDigestor

WATER

LHWPretreatment

SUBSTRATE

BIOGAS

DIGESTATE

INOCULUM

Flash

WATER

Dehydrator

CONDENSATE

AIR

Off‐gas

Scrubber

BIOMETHANE

Stripper

Figure 9. Process flow diagram for the biomethane production with LHW pretreatment.

ConditionsLiquid Hot

Water (LHW)

Anaerobicdigestion

Temperature (°C) 175.0 55.0

Pressure (bar) 10.0 1.0

Liquid solid ratio (%v/w) 8.0 46.9*

°Substrate inoculum ratio in %wt volatile solids (Cowmanure was used as inoculumn)

Table 1. Pretreatment and Anaerobic digestion operating conditions

Research group on Chemical, Catalytic and Biotechnological Processes

Processes description: Biomethane production with pretreatment stage

Biogas upgrading according to Cozma et al 2015.

Item Value Item Value

Compressors - Pr 10.0 Turbine – Pr 5.0

Compressor - ns 85.0% Turbines - ns 90%

Intercooler - Pd 1.0% Reheater - Pd 2.0%

Boiler – Pd 5.0% Turbine – Tmax in 1600.0 K

Air – fuel ratio 6.4 Equivalence ratio 4.0

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LPcompressor

AIR

IntercoolerCombustor

Heat exchanger

HPturbine

HPcompressor

SYNGAS/BIOMETHANE

Reheater

LPturbine Load

HP steam gen IP steam gen LP steam gen

HPturbine

IPturbine

HP pump IP pump

FLUE GAS

LP pump

FEEDWATER

Firing System

SYNGAS/BIOMETHANE

HP‐STEAM IP‐STEAM

Load

LP‐STEAM

Figure 10. Process flow diagram of cogeneration plant. Based on Zheng and E. Furimsky, 2003

Table 2. Main characteristics of the simulated gas turbine

Research group on Chemical, Catalytic and Biotechnological Processes

Processes description: Cogeneration system (CHP Plant)

Pr: Pressure ratio; Pd: Pressure drop, ns: Isentropic efficiency; T max in: Inlet temperature

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Research group on Chemical, Catalytic and Biotechnological Processes

Simulated scenariosScenario 1: Oil palm rachis gasification and syngas production to be used as fuel for heat and power generation inthe CHP plant

Scenario 2: Anaerobic digestion of the oil palm rachis without pretreatment and biomethane production to be usedas fuel for heat and power generation in the CHP plant

Scenario 3: Anaerobic digestion of the oil palm rachis with pretreatment and biomethane production to be used asfuel for heat and power generation in the CHP plant

Gasification Cogeneration Heat & Power

Anaerobic digestion Cogeneration Heat & Power

Liquid Hot water Anaerobic digestion Cogeneration Heat & Power

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Item Unit ValueRaw materials

OPR USD/ton 19.40Utilities

Low Pressure steam USD/ton 1.57

Mid Pressure steam USD/ton 8.18

High Pressure steam USD/ton 9.86

Fuel USD/MMBTU 7.21Electricity USD/kWh 0.10Cooling water USD/m3 0.05Potable water USD/m3 0.74

OperationOperator USD/h 2.56Supervisor USD/h 5.12

Table 3. Sales Prices used in the economic analysis

Research group on Chemical, Catalytic and Biotechnological Processes

Energy, Economic and Environmental Analysis

Environmental Assessment

Global warming potential calculation based on the CO2 emmission of each process

Economic conditions

Annual Interest Rate: 17%Tax rate: 25%

Period: 10 yearsMethod: Straight line

Energy assessment

Gas turbine thermal efficiency Net energy value

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Table 4. Chemical composition analysis of the OPR.

Research group on Chemical, Catalytic and Biotechnological Processes

Results: OPR characterization

Component

Content (% w/w)

Empty Fruit Bunches (EFB)

Palm Press Fiber (PPF)

Oil Palm Fronds (OPF),

db.

Oil Palm Rachis, db

(OPR)

Moisture 65.00 40.00 N.A 9.68Extractives N.A 2.52 N.A 15.16Oil N.A 3.48 N.A N.ACellulose 15.47 24.00 41.90 40.81Hemicellulose 11.73 14.40 36.00 22.48Lignin 7.14 12.60 22.00 16.84Ash 0.67 3.00 N.A 4.76

The OPR chemical composition is similar to other oil palm biomass that have been used for biofuels and power generation. Thus this one can be used in biotechnological processes

Bioethanol Production.

Biogas Production.

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Table 5. Proximate analysis of the OPR.

Research group on Chemical, Catalytic and Biotechnological Processes

Results: OPR characterization

Component

Content (% w/w)

Pinus Patula Coffee cut stems Oil Palm Rachis, db (OPR)

Moisture 9.21 8.70 11.71Fixed Carbon 17.64 14.57 14.73Volatile Matter 82.14 83.14 80.46Ash 0.25 2.29 4.814HHV (MJ(kg) 19.97 17.52 18.56

The OPR proximate analysis indicates that this raw material has a comparable calorific value with other biomass used in thermochemical applications such as Pinus Patula and Coffee Cut Stems

Gasification for syngas production.

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Scenario Fuel yield [kg fuel/kg OPR]

Total steam yield [kg steam/kg OPR]

1 3.60 3.50

2 0.21 2.75

3 0.26 2.37

Scenario Fuel LHV [kJ/kg] Thermal Efficiency [%] Generated Power [MW] NEV [kJ/kg OPR]

1 6.98 41.8 23.7 28574

2 26.1 39.5 20.2 26603

3 47.4 52.2 43.5 23432

Research group on Chemical, Catalytic and Biotechnological Processes

Results: Energy assessment

Table 6. Mass indicators calculated.

Table 6. Energy indicators calculated.

OPR gasification produces more fuel (i.e. syngas) and steam than its

anaerobic degradation

Technical Ranking.

Scenario 1

Scenario 2

Scenario 3

Biomethane from scenario 3 has a higher calorific value than syngas. Nevertheless, this one has better energy and mass indicators than the other two scenarios

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Research group on Chemical, Catalytic and Biotechnological Processes

Results: Economic and Environmental assessment

Figure 11. Economic analysis of each scenario according to the OPEX (gray bars) and CAPEX (black

line).

Scenario Global Warming Potential

1 1023.56 kg CO2/ton OPR

2 1294.77 kg CO2/ton OPR

3 1346.93 kg CO2/ton OPR

Table 6. Global warming potential of each scenario

Economic & Environmental

Ranking.

Scenario 1

Scenario 2

Scenario 3

Syngas production has the lowest total capital cost and environmental impact.

Biomethane production has higher capital cost than syngas due to during its

production more equipments and goods are employed

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Research group on Chemical, Catalytic and Biotechnological Processes

Conclusions

o Oil palm rachis (OPR) is a suitable raw material to be used in both thermochemical and biochemical applications due to its chemical composition, calorific power and physical structure

o Syngas production from the OPR gasification is more feasible to be used as fuel than biomethanedue to its production scheme is more simplified. Therefore, biomass gasification can be proposedas better option to take advantage of residues with high calorific values and produce heat as wellas power. However, some technical aspects such as tar generation must be considered during itsindustrial implementation

o Anaerobic digestion (AD) process is an essential part of the future biorefineries and a technologythat can be improved through the raw materials pretreatment.

C. S. Goh, H. T. Tan, and K. T. Lee, “Pretreatment of oil palm frond using hot compressed water: Anevaluation of compositional changes and pulp digestibility using severity factors,” Bioresour. Technol., vol.110, pp. 662–669, 2012

Statistical Review of World Energy,” London, UK, 2017 International Energy Outlook (IEO), “World Energy Outlook 2016,” 2016 P. Kaparaju, M. Serrano, A. B. Thomsen, P. Kongjan, and I. Angelidaki, “Bioethanol, biohydrogen and

biogas production from wheat straw in a biorefinery concept,” Bioresour. Technol., vol. 100, no. 9, pp.2562–2568, 2009.

L. F. Gutiérrez, Ó. J. Sánchez, and C. A. Cardona, “Process integration possibilities for biodieselproduction from palm oil using ethanol obtained from lignocellulosic residues of oil palm industry,”Bioresour. Technol., vol. 100, no. 3, pp. 1227–1237, 2009.

L. V. Daza Serna, J. C. Solarte Toro, S. Serna Loaiza, Y. Chacón Perez, and C. A. Cardona Alzate,“Agricultural Waste Management Through Energy Producing Biorefineries: The Colombian Case,” Wasteand Biomass Valorization, pp. 1–10, 2016.

C. A. García, R. Betancourt, and C. A. Cardona, “Stand-alone and biorefinery pathways to producehydrogen through gasification and dark fermentation using Pinus Patula,” J. Environ. Manage., 2015.

L. Zheng and E. Furimsky, “ASPEN simulation of cogeneration plants,” Energy Convers. Manag., vol. 44,no. 11, pp. 1845–1851, 2003.

P. Cozma, W. Wukovits, I. Mămăligă, A. Friedl, and M. Gavrilescu, “Modeling and simulation of highpressure water scrubbing technology applied for biogas upgrading,” Clean Technol. Environ. Policy, vol.17, no. 2, pp. 373–391, Feb. 2015.

20 References

Comparison of biomethane and syngas production as energy vectors for heat and power generation from palm residues: A techno-economic, energy and environmental assessment

Juan Camilo Solarte Toro, Yessica Chacón Pérez, Carlos Ariel Cardona Alzate

E-mail address: ccardonaal@unal.edu.co (C.A. Cardona)Universidad Nacional de Colombia sede Manizales

THANKS!!

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