Chalmers Gasifier
Experiences from the first 5 years of operation in Chalmers gasifier
Henrik Thunman
Chalmers University of Technology
Commercialization ~50 Persons research activity at Chalmers, GU, SP, MiUN are devoted to support the development
Chalmers 2‐4 MW Raw Gas Demonstration Plant
Chalmers Gasification Infrastructure
GoBiGas fas 2 Hisingen 80‐100 MW Biomethane
Commercial Plant
Göteborg Energi
GoBiGas Phase 1 Hisingen 20 MW Biomethane Pilot Plant
Göteborg Energi •
– Operated continuously November to the beginning of April ~ 4000h/year
•
Chalmers lab reactor
Boiler designed for 12 MWth
operated typically at 6‐8 MWth
Gasifier 2‐4 MW
‐ optional operation – Dual bed operation since start ~15000 h – where of ~2500 h with fuel to gasifier
3500 Million SEK
1400 Million SEK
13 Million SEK
2008
2013
2017
Processes to Consider
Specification of Chalmers Gasifier
Measurements
Variation possibilities
•
Fuel load 0 – 4 MW (0 ‐ 1 ton/h) –
•
Optional fluidization media
‐ Steam
‐ Flue gases
‐ Air (not yet tested)
Product gas composition and mass flow
•
Solid flux
Condensation of tars
•
Fuel feed
•
Temperatures
•
Pressures
•
In plant gas and bed sampling
‐ Dry pellets (tested: Wood and Bark)
‐ Wet biomass (tested: Wood chips)
•
Extraction of gas slip flow
Bed material (tested: silica sand, silica sand/Illmunite
bauxite, olivine)
Accumulated Time of Operation
•
Temperature in Gasifier 550‐900 C (tested 725 ‐ 860 C)
•
Residence time
•
Fuel
•
•
(tested: 0‐2.3 MW)
‐ Adjustable solid flux ‐ Adjustable bed height
with fuel ~2500 h
Devolatilization
Risk of agglomiration
Catalytic behaviour
Oxygen transport
Char Gasification
without fuel ~12000 h
200
700
350
800
Experimental
Experimental
Chalmers System
Gasification
900 1000
Temperature
Gas cooling and cleaning
Control room
Fuel tracking
Bed Sampling
Gas analysis
Gas Analysis
Gas Analysis
Tar Sampling
Raw Gas Contains:
H2,CO,CO2,H2O,(N2) and a large variety of organic compounds μ‐GC
μ‐GC
Tar Sampling
Improved Mass Flow Measurement of Fuel
Condensate
Cold Gas Contains:
H2,CO,CO2, (N2) and C1,C2,(C3) organic compounds
Cold Gas
0.6
Constant temperature (830 ̊C) and solids flow.
5.0
Comparison between Carbon Balance and Tar measurements show that:
Ych,F=0.18
0.5
Ych,F=0.18
Ych,F=0.16
4.0
Ych,F=0.16
Change in Steam‐to‐fuel ratio
Mass C3‐C6 ≈ Mass Tars
0.4
Over all reactions in Gasifier
Mole per kgdaf fuel
Elemental Composition of Raw Gas
1) C + 2H2O ‐> CO2 + 2H2
2) CxHyOz (+ aH2O) ‐> bCO2 + cH2
YO,G / YC,G
Chalmers Gasifier
Gas Analysis
Conversion to Simple Gas Components
Gas Analysis
YH,G / YC,G
Molar Percentage
Lab. Reactor
Gas Dryer
Gas Dryer
Helium injection, Improved steam flow measurement 0.3
2.0
Ych1,F=0
0.2
Ych1,F=0
Run
Run
Run
Run
Run
Run
0.1
0.0
0.0
3.0
0.4
0.8
YM,F+YS,F
#1
#2
#3
#4
#5
#6
1.0
1.2
0.0
0.0
0.4
0.8
YM,F+YS,F
1.2
Development of Representative Tar Measurements Water Concentration Measurements
Gas Volume Measurement
Wet Gas
Dry Gas
Naphthalene
5
4.5
Initial variation due to measurement methology
4
3.5
Condensate
10
15
Pyrene
Fluorantene
Phenanthrene
Anthracene
Fluorene
30
35
25
30
40
THz
Oven 350‐900 °C
35
Species in retention time order
Water Concentration Measurements with THz
40
Inert Gas (IR) or Insulation Material (Thz)
Gas Inlet >350 °C
Water Fraction
Gas Outlet
Raw Gas efficiency as Function of Char Gasification and Oxygen Transport
Typically level for wood
Time (min)
FTTHz
Windows
Pyrene
Fluoranthene
Phenantrene
Anthracene
Acenaphthylene
20
Acenaphthene
1-MethylNaphthalene
o-Cresol
m/p-Xylene
5
o-Xylene
Benzene
1
0.5
Toluene
1.5
2-MethylNaphthalene
Indene
m/p-Cresol
g/m3
2
25
Present variation due to measurement methology
3
2.5
Acenaphthylene
20
Balance
Species
Biphenyl
Naphthalene
Mean +- Std
15
Fluorene
Indan
10
3.5
Acenaphthene
o-Xylene
Toluene
m/p-Xylene
5
Phenol
40
Benzene
m-Cresol
p-Cresol
0
2,5/3,5-Xylenol
o-Cresol
0.5
Phenol
1
Biphenyl
Indene
2
1.5
1-Methylnaphthalene
2-Methylnaphthalene
g/m3
3
2.5
Residence time of Fuel in the Gasifier
Cold flow model
Fuel Tracking
Gasifier
Low Steam Flow
Separate of Bed Circulation and Fuel Transport
High Steam Flow
Bed Materials influence on Char Gasification (Silica sand ~25 min)
With Baffel
Without Baffel
Can Ash deposits give the same effect?
Primary and Secundary measuremnt
Catalytic Cracking of Tars
Flue Gas
Tar “Free” Flue Gas Product Gas
Ash disposal
Tar “Free” Product Gas Flue Gas
Ash Disposal
180‐250 °C
Flue Gas
180‐250 °C
230‐300 °C
830‐870 °C
900 °C
Bed Material
Biomass
830‐870 °C
Steam
Air
850‐900°C
Heat
850 °C
Raw Gas
700‐780 °C
870 °C
Air
Biomass
Bed Material
810‐850 °C
Steam
Air
Organic free, oxidized fines
750‐800 °C
Air
Biooil and Tars
900 °C
Organic rich (Tars and Char), reduced fines
Air
Fuel
Char Coal
Steam
Air
Gasifier
Organic free, oxidized fines
Only primary measures
General Conclusion Naphthalene
Naphthalene
30
•
Raw gas produced by the devolatilzation in a dual fluidized bed is enough for all proposed biofuel processes
•
Future plants with higher biofuel to biomass ratio needs that some of the Char is gasified
•
Introduction of an known amount of inert gas (e.g. Helium) with the fluidization gas make it possible relate the measured gas components to converting fuel
•
To enable a closure of the mass balance the raw gas need to be converted to a few simple gas components, for example, CO2 and H2O by combustion with an known amount of oxygen
•
A closure of the mass balance reveal that standard analysis of cold gas and tars miss hydrocarbons in the range C3 to C6, which in amount will be of the same order as the measured Tars
•
Catalytic material used for Primary reduction of Tars transport in most cases oxygen in a dual fluidized bed gasification system => need for gasification of Char
27,91
0,47
total tar concentration (g/mn3)
Solvent
Benzene
Solvent
Benzene
In
Gas Cleaning
Primery and Secondary
Exemple of Results
Ut
Cleaned
Raw Gas Biooil (RME)
30 °C
25
13,21: Total tars
2,60: Benzene
20
15
13,21
2,60
10
8,71
2,37
5
4,81
2,24
1,27
1,05
800°C
880°C
0
Raw gas
700°C
750°C
General Conclusion (cont.)
•
Bed material transport also other species between the reactor, for example, when using silca sand as bed material “all” sulfur is released as H2S in the gasifier
independent in which reactor it is initially release
•
Measurement of the water concentration in the raw gas can be done with a high frequency with THz waves and revile the characteristics of the process •
By controlling the fluidization and introducing baffles the residence time of fuel in the gasifier can be disconnected from the circulating bed material •
Potassium combined with certain bed materials can increase rate of char gasification in steam with a factor 10
•
By dividing the dual fluidized gasifier into two consecutive dual fluidized beds the management of heat and oxygen transfer can be arranged so it is possible to convert all hydrocarbons to CO and H2