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Opportunities and developments on the intensification of chemical and geochemical processes by gravity pressure vessel technology

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A multitude of chemical reactions rely on high temperatures and pressures to attain suitable kinetics and reach desirable conversions, which are commonly delivered in autoclave reactors. Traditional reactor designs (e.g. CSTRs) have large energy demands (due to pressurization and mixing demands, and heat losses) and costly construction specifications (to meet pressurized vessel codes and safety provisions), which make certain processing routes prohibitively expensive. An alternative reactor technology, which cleverly applies the principles of process integration and process intensification [1], is the Gravity Pressure Vessel (GPV). This is a special kind of autoclave with a built-in heat exchanger, plug flow configuration, and gravity driven pressurization/depressurization. Residence time is controlled by the reactor length that can reach up to 2400 m, resulting in hydrostatically built pressures that can exceed 120 bar. By continuously recycling exothermic reaction heat, up to 70% of the energy can be conserved, and high end temperatures can be achieved (up to 500 °C). In the case of slurry flow, the generated turbulence promotes particle-particle interaction, removing passivating layers and autogenously milling the reacting material, permitting post-processing separation of the mineral phases into valuable product streams. The first patent of the GPV technique was granted in 1981 (US4272383) for wet-air oxidation of sewage sludge. This process was in operation for 12 years in Apeldoorn (the Netherlands), reducing chemical oxygen demand (COD) by >70% and generating up to 10 MW in heat output. Recently, Innovation Concepts B.V. patented the ‘CO2 Energy Reactor™’ (WO2011/155830A1), an application of GPV to mineral carbonation. This is an economically viable, socially acceptable and environmentally sustainable process that permanently sequesters CO2; an alternative to underground storage. It utilizes alkaline minerals (virgin or waste-derived), rich in calcium (e.g. wollastonite, steel slags and incineration ashes) or magnesium (e.g. olivine, serpentine, asbestos and mine tailings) as carbon sinks. Besides carbon capture, valuable product streams also emerge: precipitated carbonates, amorphous silica, and enriched metal residues. This solution results in the stabilization or detoxification of hazardous industrial wastes, and in the valorisation of abundant low-value minerals. The GPV technology is also being developed for the oil sands industry. Bituminous sands are a type of unconventional petroleum deposit consisting of a mixture of sand, clay, water, and a dense and extremely viscous form of petroleum (the bitumen or “tar”). GPV technology is a sustainable solution to one main problem area: oil sand tailings treatment. Wet-air oxidation permits the conversion of MFT (Mature Fine Tailings) to TTT (Thermally Treaded Tailings), wherein residual bitumen in MFT is used as energy source for the process. The outcome is reduced settling time, metals oxidation, reduced contaminants leaching, and freed water that can be re-used in the separation process. This work reports on the technical aspects of the GPV technology, and on the latest developments, challenges and outlook for its adaptation to the considered applications and adoption by the mainstream industry. [1] Santos, R.M., Van Gerven, T. (2011) Process intensification routes for mineral carbonation. Greenhouse Gases: Science and Technology 1(4), 287–293.
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Opportunities and developments on
the intensification of chemical and
geochemical processes by
gravity pressure vessel technology
Rafael M. Santos, Tom Van Gerven
KU Leuven, Dept. Chemical Engineering, Leuven, Belgium
Pol Knops, Keesjan Rijnsburger
Innovation Concepts B.V., Gorinchem, The Netherlands
Fourth European Process Intensification Conference
(EPIC 2013)
Outline
Working principle
History
Opportunities under consideration
Mineral carbon sequestration
Asbestos remediation
Oil sand tailings treatment
Developments of Innovation Concepts
Working Principle
Gravity pressure vessel (GPV) step by step
GPV 1
B
A
A: Incoming material
B: DownComer tube
Pressure increases
Pre-heating medium
0 meter
-1200 meter
GPV 2
B
A
A: Incoming material
B: DownComer tube
C: Gas injection
Exothermic reaction -> Energy production
C
C
C
C
C
C
D
GPV 3
B
C
C
C
A
D
A: Incoming material
B: Downcomer tube
C: Gas injection
D: Upcomer tube:
Releases energy to downcomer
Pressure decreases
Leaves the reactor
E
D
GPV 4
B
C
C
C
A
C
E
E
E
A: Incoming material
B: Downcomer tube
C: Gas injection
D: Upcomer tube:
E: Surrounding tube
Start-up heating (ignition).
Steady-state (autothermic) cooling
and energy harvesting.
Advantages
obuilt-in heat exchanger: heat conservation,
utilization and recovery.
ohydrostatic pressurization: low energy demand.
Advantages
oturbulent three phase flow: promotes heat and
mass transfer, autogeneous milling and
passivating layer erosion.
Advantages
oplug flow configuration: continuous process, no
moving parts.
ounderground installation: safe/inexpensive
reactor design.
Input Output
Low P Gas
Surface level
Underground
History
Patent 4,272,383, McGrew (1981)
“Method and apparatus for effecting subsurface,
controlled, accelerated chemical reactions”
Sewage Sludge Wet Oxidation:
Longmont, Colorado (USA)
Moved to Apeldoorn
Apeldoorn (The Netherlands)
VerTech process
1992-2004 US 4,272,383
History
VerTech Process
Throughput 120 m3/hr
Energy production
Recovery
9.5 MW(th)
50% @ 260 °C
Energy density 340 J/kg
Gas injection O2: 2.4 tonne/hr
Max. temp
Depth
270 °C
1200 m
Installation
Conventional drilling:
Straight, 30”
Commissioning
Identification:
Accelerate reaction kinetics.
Integrate and recover exothermic reaction heat.
Valorize low value residues into products.
Approach:
Focus towards full scale installation.
Build on existing R&D.
Harvest past experience.
Opportunities
Opportunities
Mineral carbon sequestration:
Natural minerals: olivine, wollastonite, serpentine.
Industrial residues: slags, ashes, tailings.
Waste remediation:
Asbestos containing-materials (mining tailings
and construction materials).
Oil sand tailings.
Mineral Carbon Sequestration
Olivine:
(Mg,Fe)2SiO4 + 2CO2 => 2(Mg,Fe)CO3 + SiO2
[∆H = -89 kJ/mol CO2]
Wollastonite:
CaSiO3 + CO2 => CaCO3 + SiO2
[∆H = -87 kJ/mol CO2]
Serpentine:
Mg3Si2O5(OH)4 + 3CO2 => 3MgCO3 +2H2O + 2SiO2
[∆H = -64 kJ/mol CO2]
Reaction rate
T.A. Haug, 2010.
PhD Thesis
, NTNU.
S.J. Gerdemann et al., 2003. S
econd Annual Conference on Carbon Sequestration,
Alexandria, VA, USA.
Time (hr) pH
Temperature (°C) Pressure (atm)
Mineral Carbon Sequestration
Reaction profile
Temperature profile
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
Conversion
200
150
100
50
0
Temperature C)
Carbonation conversion profile
reactor length (m) reactor length (m)
0 500 1000 1500 2000 0 500 1000 1500 2000
heat
10 μm, 0.7 kg/kg
Mineral Carbon Sequestration
R.M. Santos et al. 2012.
11th International Conference on Greenhouse Gas Control Technologies
, Kyoto, Japan.
Autothermic map
(a) 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
10 4% 5% 100% 99% 96% 92% 89% 85% 82% 79%
20 4% 4% 4% 85% 80% 76% 72% 68% 65% 62%
30 4% 4% 4% 4% 69% 65% 61% 58% 55% 53%
40 4% 4% 4% 4% 4% 57% 54% 51% 49% 47%
50 - - - - - 4% 49% 46% 44% 42%
60 - - - - - 4% 4% 42% 40% 39%
70 - - - - - 4% 4% 4% 37% 36%
80 - - - - - 4% 4% 4% 4% 34%
(b) 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
10 29 34 79 97 114 129 142 153 163 171
20 28 29 32 92 104 114 122 130 137 143
30 28 28 29 32 93 102 109 115 120 125
40 28 28 29 30 32 93 99 104 109 113
50 - - - - - 32 91 96 101 104
60 - - - - - 31 32 90 94 98
70 - - - - - 30 31 33 88 92
80 - - - - - 30 30 31 33 87
particle diameter (μm)
solids loading (kg,solids/kg,liquid)
solids loading (kg,solids/kg,liquid)
particle diameter (μm)
carbonation conversion
outlet temperature (°C)
Outlet carbonation conversion (%)
Mineral Carbon Sequestration
R.M. Santos et al. 2012.
11th International Conference on Greenhouse Gas Control Technologies
, Kyoto, Japan.
Carbonation products
Fully carbonated olivine
Fresh milled olivine
Mineral Carbon Sequestration
amorphous silica (SiO2) magnesite (MgCO3)
Asbestos Remediation
Chrysotile (white asbestos): Mg3(Si2O5)(OH)4
Tremolite: Ca2Mg5Si8O22(OH)2
Fibre cement (historical): 90% cement, 10% chrysotile
http://en.wikipedia.org/wiki/File:
Chrysotile_SEM_photo.jpg http://en.wikipedia.org/wiki/File:
Wellasbestdach-233-3354_IMG.JPG
Asbestos Remediation
Oil sand tailings: sand, clay, water and residual
bitumen (‘tar’).
MFT (Mature Fine Tailings) + O2 =>
TTT (Thermally Treaded Tailings)
Aim:
reduce settling time;
oil and metals oxidation;
reduce contaminants leaching;
free water for re-use;
autothermic process.
Oil sand tailings Treatment
http://en.wikipedia.org/wiki/File:
Syncrude_mildred_lake_plant.jpg
Oil sand tailings Treatment
P. Knops. 2011.
RemTech 2011
, Banff, Canada.
Temperature (°C)
350
300
250
Time (min)
60
30
60
30
60
30
% COD reduction
86.3%
85.3%
82.9%
81.2%
70.6%
69.6%
COD reduction test
Oil sand tailings Treatment
P. Knops. 2011.
RemTech 2011
, Banff, Canada.
Settleability test
Developments
Split into various stages:
Patent application
Batch autoclave
Research consortium
Continuous autoclave
Pilot reactor
Full scale
Batch rocking autoclave (now under testing)
Simulate GPV characteristics:
Tubular hydrodynamics.
Transient T and P.
Generate fundamental understanding:
Reaction rates.
Particle exfoliation.
Passivating layers.
Product mineralogy.
Developments
Consortium agreement:
- Sibelco (olivine producer)
- Steel company (CO2 producer)
- Institute for Sustainable Process Technology (ISPT)
- KU Leuven
- Dutch University
- Innovation Concepts (technology holder)
Developments
Learn more about us:
set.kuleuven.be/mrc/sim2
www.innovationconcepts.eu
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