Gasification Kinetics of Coal and Biomass

Estefania AlbaMerced RamirezJoshua Felton

Outline1. Objective2. Introduction/Background3. Methodology4. Results5. Conclusion

Objective1. The goal of this research

project is to study the effect of blending biomass with coal on the gasification reactivity.

Gasification of coal and biomass can increase efficiency and reduce carbon dioxide emissions.

IntroductionWorld Primary Energy Production by Source 1990, 2006. (Quadrillion Btu)

BackgroundBiomassCoal

ADVANTAGES•Enormous world stock•High energy density•Relatively low cost•No seasonal limitations

DRAWBACKS•Environmentally harmful compounds (S, N,CO2)•Low H/C ratio•Non renewable source

ADVANTAGES•Economic way to dispose waste•Content less pollutants•Carbon neutral •High H2 contentDRAWBACKS•Low energy density•Seasonal limitation•Poor reliability in supply•High moisture content

Background

Gasification is an endothermic reaction between a carbonaceous fuel and a gas in a reactor where the oxygen supply is limited (partial oxidation).

Combustion is an exothermic reaction between a fuel and an oxidizer.

Fuel + oxygen (limited) + Steam/CO2 →hydrogen + carbon monoxide + (some water and carbon dioxide + light

hydrocarbons )

Fuel+ oxygen →heat + water+ carbon dioxide

Methodology

Biomass has a fibrous structure which makes it hard to grind

Hammer mill

Coal is easier to grind due to Coalification

Ball mill or Bar/rod mill

Coal: Bituminous coal (Pittsburgh #8)

Milled to: < 140 mesh(<105 μm)Biomass: Switchgrass

Milled to:60-120 mesh (250-125 μm)120-200 mesh (125-74 μm) < 200 mesh (< 74 μm)

MethodologyProximate analysis determines the percentage composition of moisture, volatile matter, fixed carbon and ash

MethodologyUltimate analysis determines the elemental

composition

MethodologyDrop Tube Furnace

Feeder

Collection Probe

Furnace

Methodology

Sample Biomass: 60-120 mesh Coal: < 140 mesh

Blend ratio (Energy basis)

Method1. Moisture 107℃ in N2 (Flow rate100 ml/min)

2. Volatile 950 ℃ in N2 (Flow rate100 ml/min)

3. Char 950 ℃ in CO2 (Flow rate100 ml/min)

The Thermo Gravimetric Analyzer is used to determine the rate of reaction

Coal % Biomass %100 070 3040 600 100

Results

Calorific Value  Btu/lb kJ/kgSwitchgrass, <200 6996.8

16274.5

Switchgrass, 120x200 7294.3

16966.6

Switchgrass, 60x120 7307.7

16997.7

Coal < 140 8836.520553.

9

Proximate Analysis  Moist % Vol % FC % Ash %

Switchgrass, <200 9.1 67.2 12.7 10.9

Switchgrass, 120x200 9.5 72.9 12.8 4.8

Switchgrass, 60x120 9.9 73.9 12.5 3.7

Coal <140 10.0 39.9 41.3 8.9

Ultimate analysis dry ash free basis

  C % H% N % S % O %Switchgrass, <200 50.5 7.6 1.8 0.7 39.5Switchgrass, 120x200 49.4 6.7 1.5 0.7 41.7Switchgrass, 60x120 47.6 6.9 1.1 0.6 39.8

Coal <140 74.2 5.4 1.0 1.2 18.2

Results

ConclusionA blend of 60% biomass and 40% coal: reacts faster than other blends

Use of biomass in thermochemical processes can

increase efficiency reduce CO2 emission reduce emission of other environmentally harmful

compounds

AcknowledgementsEberly College of Science Daniel J. LarsonCollege of Earth and Mineral

SciencesWilliam E. EasterlingDr. Sarma PisupatiAime Hilaire TchapdaBrandon EmigJody MarkleyDerek JamesUBMS Staff