Post on 25-Sep-2015
description
transcript
Co Processing of AFR in Holcim and its
Enhancement with CFD
Anne Dekeukelaere and Tom Lowes, CIE AFR BD
2
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
Scope of Paper
Holcim
Waste and co-processing
Rules of the game
Technical Issues
Computerized Fluid Dynamics
Conclusion
3
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
Who is Holcim?
With majority and minority interests in more
than 70 countries on all continents, Holcim is
one of the world's leading suppliers of
cement, as well as aggregates (gravel and
sand), concrete and construction-related
services.
Employees: 61,000+
Production capacity: > 160 Mio tons
Net sales 2005: 18.5 billion CHF
Member of World Business Council for
Sustainable Development (WBCSD)
Selected as an index component for the Dow
Jones Sustainability World Index and the
European Dow Jones STOXX Sustainability
Index
4
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
Holcim presence: balance between emerging and
mature markets
USA
Canada
Ecuador
Chile Brazil
Venezuela
Colombia
South Africa
Madagascar
Australia
New Zealand
Philippines
Vietnam
China
Lebanon
Austria
Germany
Switzerland
Belgium
France
Spain
Morocco
Guinea
Ivory Coast
Burkina Faso
Russia
Guayana
Peru
Czech Republic
Hungary Croatia Estonia
Italy
India
Argentina
Slovakia
Tanzania
La Reunion
Cambodia
Sri Lanka Egypt
Rumania Bulgaria
Uzbekistan
Malaysia
Thailand
Macedonia
Mexico
Honduras
El Salvador
Costa Rica
Nicaragua
Dominican Republic
Netherlands
Cyprus
Haiti
Singapore
Nigeria
Guatemala Caribbean
Azerbaijan
USA
Canada
Ecuador
Chile Brazil
Venezuela
Colombia
South Africa
Madagascar
Australia
New Zealand
Philippines
Vietnam
China
Lebanon
Austria
Germany
Switzerland
Belgium
France
Spain
Morocco
Guinea
Ivory Coast
Burkina Faso
Russia
Guayana
Peru
Czech Republic
Hungary Croatia Estonia
Italy
India
Argentina
Slovakia
Tanzania
La Reunion
Cambodia
Sri Lanka Egypt
Rumania Bulgaria
Uzbekistan
Malaysia
Thailand
Macedonia
Mexico
Honduras
El Salvador
Costa Rica
Nicaragua
Dominican Republic
Netherlands
Cyprus
Haiti
Singapore
Nigeria
Guatemala Caribbean
Azerbaijan
5
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
Cement industry characteristics
Cement Is an Energy and Capitally Intensive Industry and annually Holcim needs to acquire:-
@ 18 mtpa of coal or equivalent @ 12 Twh of Electricity
The high thermal Energy comes from the needs to sinter Limestone and Argillaceous Components (Al2O3, SiO2, Fe2O3) at @ 1450C to produce clinker, that is then ground to cement with gypsum and in some cases extenders
Energy costs run at @ 30 % of production costs and @ 65% of variable costs
At current UK Greenfield Site Costs 180 /tpa) to renew Holcim Global capacity would cost in excess of $ US 40 Billion
A typical New Plant is a calciner with 2.5 tpa capacity
6
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
Sustainable development and Holcims mission
Sustainable Development is a core
element of Holcims Mission:
Our mission is to be the worlds most respected and attractive company in our industry creating value for all our stakeholders.
Our goal is to continually demonstrate our
commitment to sustainable Environmental
Performance, and visibly play a leading
role in Social Responsibility within our
sphere of influence.
7
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
Holcim triple bottom SD
Because of its Energy Intensive nature and Size of
Installations, Holcim is very much aware and is
committed to the needs for Sustainable Development
Social progress
Economic growth
Environmental performance
Sustainable
Development
8
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
Our SD priorities
We have outlined strategies and set targets in
clearly defined priority areas including:
Occupational health and safety (OH&S)
Climate and energy
Community involvement
Stakeholder relations
Sustainable construction
9
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
Field for
AFR-BD
BUILDING
infrastructure
Natural
Resources ENERGY
fuels
Emissions CO2
Conservation of non-renewable natural resources
QUARRY
limestone
QUARRY
aggregates
MILL
cement
KILN
clinker
READY MIX
concrete Operations
Substitutes Recycled
building
materials
By-products
from other
industries
Alternative
fuels / waste
materials
Holcim is
increasing the
use of
alternative
fuels & raw
materials
Recovery from energy and material from selected waste leads to
the conservation of non-renewable natural resources
10
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
Emissions from fossil fuel and waste as fuel
Waste incineration & cement
manufacturing
Waste as fuel in cement
manufacturing
GHG
GHG
GHG Emissions
Waste
Incinerator Cement plant + Cement plant
Waste Fossil Fuels Waste Fossil Fuels Resources
11
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
The GTZ-Holcim partnership
GTZ is a German-based organization promoting international cooperation on sustainable development. It operates on a worldwide basis.
The Holcim-GTZ partnership has produced guidelines on Co-Processing of Waste Materials in Cement Production.
The purpose of these guidelines is:
to reduce deficiencies in waste management;
to provide objective information about co-processing in the cement industry;
to propose realistic and achievable standards, suitable for and acceptable to all stakeholders involved;
to enable capacity building and to offer a joint platform for institutions and
companies active in the field of co-processing.
See www.coprocem.com
12
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
Scope of Paper
Holcim
Waste and co-processing
Rules of the game
Technical Issues
Computerized Fluid Dynamics
Conclusion
13
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
What is co-processing?
Co-Processing refers to the use of waste materials in
industrial processes, such as cement, lime, or steel
production and power stations. It is a recovery of energy or
material from waste. The cement industry is the only industry which does both at the same time
Calciners all Shapes
and Sizes,
depending on
Manufacturer, need
CFD to otimise for
AFR and PC
14
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
Waste and co-processing
What is AFR Co Processing in Holcim :- It is the preservation of natural raw materials by the use of
Industrial Waste or by products as a source of Energy and or Raw Materials for Cement Production, without:-
- Increase in Emissions
- Degradation of Cement Quality
This is no easy task plus as most of the Holcim World is a sold
out market and wastes are not coal or well prepared raw materials.
Considerable effort and expertise has needed to be developed and investments made to ensure Emissions and Cement Quality Standards are maintained as well minimal production loss occurring
15
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
Waste and co-processing
What is AFR Co Processing in Holcim (Contd) :-
The minimisation of the impact on production is done via the
consideration of the details of the total process from the
service(TSS) to the Country/Community in helping with their
waste problem to the final cement product and its customers
Holcim has developed a series of AFR Co Processing Business
Units Globally to acquire and prepare AFR for the Cement
Process
Holcim has developed detailed understandings and capital
investment required to process waste into a fuel for all types of
cement plants, in order to ensure its Co Processing Goals are
achieved Globally
16
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
Holcim is increasing its thermal substitution rate
Acid tar deposit Landfilling Industrial wastes Hydrocarbon sludge's
Plastics mixtures
Used tires
Thermal Substitution Rate by Alternative Fuels
0
5
10
15
20
25
30
35
40
Africa Asia-Pac Europe LatAm NthAm Group
% t
he
rma
l e
ne
rgy
fro
m a
lt.
fue
l
1990 2005 2008 Forecast
22
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
Waste Management Hierarchy
Cement
Industry
25
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
Scope of Paper
Holcim
Waste and co-processing
Rules of the game
Technical Issues
Computerized Fluid Dynamics
Conclusion
27
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
The 9 principles of our AFR policy
Elements of
sustainability
I. Act as a partner to society by offering waste
management solutions
II. Keep our environment safe
III. Add value to our core business
What we will do IV. Ensure occupational health & safety
V. Refuse the listed banned wastes
VI. Guarantee the quality of our products
How we will do it VII. Comply with the relevant regulations and
promote best practices
VIII. Monitor and control the inputs, process, products
and emissions
IX. Communicate transparently
When using AFR our goal is to:
No Increase
in Emissions
No volatile
organics in
ARM and
EMR
Consistent
with GTZ PPP
29
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
Scope of Paper
Holcim
Waste and co-processing
Rules of the game
Technical Issues
Computerized Fluid Dynamics
Conclusion
30
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
Technical Issues
The Technical Issues associated with the use of AFR are significant but fascinating.
Investment in the appropriate Preparation and Handling systems ($$$s) application of Rigorous QA/QC and OH&S protocols are necessary precursors of a good Co processing operation.
Once these are taken care of then the main issues to be taken care of are:-
Combustion/Emissions
Cement Quality
Production
31
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
AFR Combustion /Emissions
Issues come from several areas:-
Ensuring that the AFR has sufficient TOM&T (Temperature,
Oxygen, Micro mixing and Time )for high DREs, hence avoiding increased organic emissions.
- Need 2 secs > 800C and 1% O2 micro mixed with the fuel to
ensure all organic bonds and broken and combusted
Controlling the total metals inputs to ensure that emissions limits
are met.
Ensuring that the impact traditional raw materials and their
impact on SO2, CO, VOC Dioxins, plus other micro pollutants
are fully understood and tracked
- Need to ensure that these impacts are separated from AFR, as
this has led to erroneous conclusions on the impact of AFR on
emissions being reported
32
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
AFR Combustion /Emissions
For AFR via the Flame, the TOM&T is far in excess of what is needed for complete combustion, even with the most strong
organic bond.
The US EPA require a demonstration of a DRE of 99.99% for
Haz waste in both the flame and calciners to get a permit
A recent test burn carried out by SINTEF for pesticides on the
Holcim Plant in Vietnam resulted in > 99.9999, with numbers < 9
coming from LODs
33
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
AFR Combustion /Emissions
The next slides
Shows how emissions of D&Fs, VOC and HCl with Haz waste firing into the burning at 20% TSR with 1.5% Cl
has no influence on these emissions.
How the 40% TSR with tyre chips in a calciner has no
impact on D&Fs, but give indications how insufficient test points could give erroneous conclusions due to the
impact of organic in the raw materials
How in the trials above the tyre chips drop the overall
NOx emissions
Dioxins, HCl and VOC vs Baseline and RLF
0
5
10
15
20
25
RLF RLF B RLF B B RLF RLF RLF B RLF RLF
Baseline or RLF
HC
l, V
OC
pp
m
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
Dio
xin
s n
g/N
m3
te
q
HCl VOC's Dioxins & Furans Linear (VOC's) Linear (HCl)
40% TSR from tyre Chips in Calciner with RT @
2secs
The variation is due to the
variation of organic C in the raw
materials
Drop in NOx by 27% with Tyres Chips at an 24%
Overall TSR
38
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
AFR Combustion /Emissions
The WHO safe limit for Daily Dioxin intake is 1 pg/kg.bwt.day
At 0.1 ng TEQ/Nm3 at 10% O2 and dioxin trail with a stack dilution factor to the MEI of 100,000 results in 100 times lower than the WHO.
The emission from the Cement Industry stacks that comes closest to WHO Air Quality standards is NOx, with between 5 and 20% of the limit for the MEI resulting from plume dispersion modelling.
AFR normally drop the NOx emission, a typical drop of 20% with 20% TSR, as demonstrated means no emission of NOx from the AFR hence more than compliant with the Incinerator limit of 200 mg/Nm3 from the AFR
This indicates that there can often be an overall reduction in emissions with AFR and a positive impact on the Integrated Environmental Index, as is in fact needed in the UK to get and AFR Permit
39
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
AFR Combustion /Emissions
Metals emissions are normally not a problem as the Cement Industry can normally readily meet the 2000/76/E directive for :-
Class 1 0.05 mg/Nm3 at 10% O2 Class 2 0.05 mg/Nm3 at 10% O2 Class 3 0.5 mg/Nm3 at 10% O2
This is because of the high retention factors for metals within the clinker generally > 99%, that means little goes up the stack.
For the more volatile metals (Hg, Cd and Tl) with lower retention factors the specification of AFR is controlled to ensure that these emissions limits are readily met
Holcim's average Hg emission throughout the group is < 0.02 mg/Nm3 at 10% O2, coming primarily from coal and raw materials
The WHO annual AQS limit for the MEI is 1ug/Nm3 , the above emission by stack dispersion modelling is < 1% of the AQS
41
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
Cement Quality
There is little impact of AFR on Cement Quality providing the
guidelines are followed:-
There are two main potential problem areas for the cement plant
and its customers are:-
Variable burning
- Taken care of via QA/QC and CAPEX
Change in clinker chemistry that impact on key properties
- Taken care of via specification of AFR, ensure no metal in clinker is >
0.2% from fuel,and raw materials, plus adjustment of raw materials as
needed e.g
- Limiting MBM or sewage sludge so that P2O5 does not go > 0.3% in
the clinker
- Increase in raw material LSF by 4% to incorporate 20% TSR with rice
hulls
42
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
Cement Quality
The impact of metals contained in the clinker can cause concern
and phrases such as pollutants not transferred to the product appear in EU missives.
Metals may be pollutants once they go up the stack and hazardous
in their powder form, but in capsulated in the clinker mineral
structure they are primarily inert and do not leach.
As part of the Applications of the AFR Policy, Holcim will be
taking regular clinker sample and carrying out leaching tests
Holcim in its survey of 64 kilns has not found a trend between AFR
and metals in clinker, indicating that the clinker metals are coming
primarily from the raw materials, the data from this survey is shown
on the next slide, where although the % TSR has gone from 10 to
20% over 6 years the metals in the clinker remain essentially the
same
43
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
Cement Quality
44
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
Production
The biggest concern of the Cement Plant Manager with using AFR is its impact on Production rate.
QA/QC, Preparation and Handling resolves a lot of basic potential problems, however natural laws come into force that need innovative solutions to mitigate production loss.
Generally AFR is wetter than coal/petcoke and cannot be readily dried
1tph of extra H2O in the system generally equates to 2 tph production loss, if the process is fan limited
Hence flow bottlenecks have to be found and eliminated or exhaust fan capacity increased, etc
Water decreases flame temperature and hence reducing heat transfer and potentially reduces kiln output rate as a function of TSR burner configuration
Generally AFR is coarser than coal/petcoke and hence combusts more slowly and again potentially reduces production rate as a function of TSR and calciner configuration
45
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
Production
Burner and Calciner Configurations and Design need to be considered to maximise % AFR as a function of its type, properties and quality
The Cement Plant is not a ideal experimental tool, due to:-
Needs to Produce Lead time Cost of the modifications
Holcim over the last 2 years have found that working with CINAR on the use of Computerised Fluid Dynamics (CFD) to optimise the Combustion and Heat Transfer process in both the Burner , Kiln and Calciner a low cost shortcut to increasing the use of AFR
46
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
Scope of Paper
Holcim
Waste and co-processing
Rules of the game
Technical Issues
Computerized Fluid Dynamics
Conclusion
47
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
Computerized Fluid Dynamics (CFD)
Over the last 2 years Holcim with CINAR have used CFD to:-
Optimise AFR injection points into calciners and increase the % AFR
Assess the impact of AFR and burner modification on emissions as a prerequisite to applying and getting permit for trial
Assess the impact of AFR into mid kiln on emissions Assess how micro mixing of O2 with the AFR can be optimised to
get better combustion using Swirling Air and Mixing Fan system Develop the optimum burner and calciner configurations for an
8000 tpd plant for 65% TSR from Rice husks and Palm Kernel Shells in Indonesia
- This is Holcim biggest Biomass projects involving @ 400,000 tpa of Biomass
Assess how the impact on Kiln hood geometry and flow misalignment around the burner resulting in high CO and kiln build ups can be best overcome.
- Typical prediction are shown on the next slides
49
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
51
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
Computerized Fluid Dynamics (CFD)
The Tertiary Air take off from the side of the kiln hood is producing
more flow around the burner on one side than the other
Apart from giving poor combustion on one side of the burner, it also
induces a swirling flow that moves the coal into a low O2 region
which produces more CO and build up.
The cheapest potential solution is a wedge in the cooler throat to
direct more flow to side the has the lowest air flow.
This has to be done before AFR via the burner can be considered.
Without CFD the cause or the solution would not have been
obvious
CFD to a powerful tool ,do not just play with it USE IT, as Holcim
has/is doing in North America, Spain, Mexico, Switzerland and the
Philippines, with planned activities in other GCs.
52
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
Scope of Paper
Holcim
Waste and co-processing
Rules of the game
Technical Issues
Computerized Fluid Dynamics
Conclusion
53
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
Compared to other cement producers:
Holcim realized that AFR is a complete business line and not just a
procurement activity - Communication / lobbying - Marketing and channel management / customers - Production - HR
Holcim is driving the AFR market development
A comprehensive know how of all aspects of co-processing is available
Main competitive advantages of Holcim AFR business
compared to other players in the value chain
Compared to other waste management solutions than co-processing in cement kilns:
Kilns are available (with potential global coverage)
Know How in co-processing is available
Co-processing is an increasingly accepted sustainable waste
management solution
Strong public private partnerships of Holcim
54
Holcim Group Support AD/TML Global Fuels Conference London 5th Feb
Benefits of co-processing
Provides a permanent solution to waste management
problems
Lessens reliance on fossil fuels
Preserves natural resources
Reduces emissions and greenhouse gases
Saves on fuel costs
In short . . .
Co-processing is the environmentally-friendly
alternative for responsible industries.