Heat Recovery Eng 060829
Transcript of Heat Recovery Eng 060829
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DMESTON
The EdmestonHeat Recovery SystemCarbon Black - Glass - Steel
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Edmeston provides you with the most efficientHeat Recovery Systems for optimum fuel savings
Source: China Carbon Black Institute 2001
Edmeston is an engineering company established in1984 and belonging to the Sandvik Group.
Edmeston designs and sells advanced equipment andsystems for the manufacture of sulphuric acid, sodiumhydroxide etc, as well as heat recovery systems for theglass, carbon black and steel industries.
EDMESTONs major business lines:
Edmeston Heat Recovery Systems for
- Carbon Black
- Glass, INKA
- Iron and Steel
Edmeston SX Systems for Sulphuric AcidIndustry
Our business is based on:
- A unique know-how in developing and manufacturingvarious steel grades, possessed by our parentcompany Sandvik
- Our own strong process and material technologyknow-how
- Our capabilities in design, manufacturing andmarketing
Our business is focused on:
- Development and delivery of advanced, customizedequipment and systems
- Supporting our customers in construction andcommissioning
- Providing cost effective and technically optimizedsolutions
For further information please visit the Edmestonhomepage atwww.edmeston.com
ENERGY SAVING -MORE IMPORTANT THAN EVER
With increasing oil prices and higher environmental taxesmany industrial processes can make substantial costsavings by installing a heat recovery system. During thelast 15 years, oil prices have increased 60-70%. Theincentive to recover energy is and will become more andmore evident.
Heat recovery also means lower exhaust gas volumesand lower emissions to the atmosphere. Heat recoverygives direct savings in terms of lower fuel consumptionas well as indirect savings in lower environmental impact.
Last, but not least, it facilitates smaller and moreeconomic furnaces.
Thus, heat recovery is a key factor to stay competitive inan even harsher economic environment.
The example below illustrates the substantial annualsavings achieved by preheating the combustion air in acarbon black plant.
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OIL PRICE 1988-2003USD / barrel
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Annual Saving at different oil pricesCarbon Black 100 tubes Air Preheater (kUSD/year)
1 kUSD = 1000 USD
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Preheating temperature (C)
AnnualSaving(kUSD
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34 USD / barrel
20 USD / barrel
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A carbon black 800C Air preheater for lower fuel consumption
and energy saving
OUR SOLUTIONS
A heat recovery system from fluid gases often consistsof a recuperator, i e a heat exchanger absorbing andtransferring heat into another fluid.
If the heat is directly returned into the primary process,typically by preheating the combustion air, energy saving
is achieved.Preheating the combustion air in the carbon blackprocess or in a glass furnace results in considerablesavings.
Depending on current oil prices, a typical pay back timeof the investment is 1 - 2 years.
Heat recovery systems from Edmeston cover a widerange of industrial applications and technical solutionsfor different temperature ranges. Our solutions are basedon Sandviks high temperature materials with proven
reliability and long lifetime.
In some applications it is possible to achieve a lifetimeof 10 years or more.
CARBON BLACK AIR PREHEATERS
The technology gives a possibility to preheat cold air to800-900 C by taking the heat from the exhaust gasfrom the carbon black reactor. The preheated air is thenused as combustion air in the burner.
Our scope of supply is shown below:
Edmeston provides two types of air preheaters:double and single shell design.
The figure illustrates the basic principles of the two typesof airpreheaters:
The double shell type is of a non-fouling design. Itconsists of one inner and one outer shell. The air ispreheated in the annular air gap, minimizing the thermalgradient in the upper part. This reduces the foulingtendency.
This type is widely recognized for its low maintenancecosts and few production stops.
The number of cleanings due to fouling is minimized.
Both the single and the double designs are equipped withan air cooled double bottom tube sheet. This design hasproved itself to secure maximum lifetime for the bot-
tom part.
The air is flowing in counterflow to the carbon blackgas inside the fire tubes and passing through bafflesplaced all the way downstream.
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Air inletAir outlet
Filter
Air Preheater
Quench water
Reactor
Our scope of supply
Additives
Natural gas
Carbon Black
ApplicationType of
recuperatorHeat transfer
by
Flue gas inlet
temp oC
Preheat tempoC
Carbon Black Tube BundleRadiation +Convection
900 - 1030 650 - 900
GlassTube bundle orDouble Shell
Radiat ion 1250 - 1400 400 - 800
Mineral Wool Tube Bundle Radiation 1100 - 1400 550 - 650
Iron and steel Tube BundleRadiation +Convection
700 - 1100 400 - 650
CB gas in
Air in
Air out
CB gas out
Coolingair out
Coolingair in
CB gas in.
Air in Air out
CB gas out
Coolingair in
Coolingair in
DOUBLE SHELL SINGLE SHELL
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One unit ready for delivery
Top and bottom view of a carbon black airpreheater during assembling
Edmeston has supplied air preheaters to the carbon blackindustry since 1992. So far around 20 units have beeninstalled worldwide.
The sizes range from 76 to 144 tubes. The nominal airflow 10 000 28 000 Nm3/hr and the air preheattemperature 740 800C .
Edmeston also has a design concept for a 900
C air pre-heat temperature unit.
Our material selection is based on Sandviks hightemperature material technology. High temperatureresistant materials such as 253 MA etc are used in tubesand shells. Ferrules in fire tubes are made of GRX -a special and unique material with exellent hot corrosionresistance in reducing high carbon content atmospheres.
GLASS RECUPERATORS - INKA
Edmeston INKA glass recuperators have beendeveloped during more than 50 years of serviceexperience of the glass industry. More than 400recuperator systems have been installed over the yearsand the applications cover most glass types, such as con-tainer glass, C glass, E glass, technical glass, TV glass and
crystal glass.
Out of the 400 systems supplied, 40 % are of thecombined tube bundle and double shell types, 30 % aretube bundles and 30 % are double shell systems.
The heat recovery is recuperative (not regenerative ). Itis used for air preheating up to 800C, and for furnacesizes of 10-400 ton/day.
The recovery process is based on preheating air bytransferring heat from the exhaust gases to the cold air.
The preheated air is then transported back to the burnersin the glass furnace.
The exhaust gas flows inside the tube bundle and the airflows inside the tubes. Normally, parallel flow is usedbetween exhaust gas and air.
Edmeston glass recuperators can be designed as a tubebundle, as a double shell or as a combination of thesetwo types, as shown in the table below:
The energy saving potential is illustrated in the diagrambelow. For a typical flue gas temperature of 1350C andair preheat temperature of 800C, the energy saving is
about 45%.
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Tube Bundle andDouble Shell Tube Bundle Double Shell
Air preheat temp oC 800 750 550
Flue gas temp oC < 1450 < 1450 < 1200
Furnace size (ton/day) 50 - 400 50 - 400 10 - 70
Investment level, KUSD 125 - 1200 90 - 800 30 - 70
SAVINGS IN FUEL CONCUMPTION AT DIFFERENT FLUE GAS INLET ANDAIR PREHEAT TEMPERATURES
Calculation according to "The Handbook of Glass Manufacture"
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1000 1050 1100 1150 1200 1250 1300 1350 1400 1450 1500
Flue gas temperature (C) before air preheat
Fuelsaving(%)
600 C
700 C
800 C
900 C
A unit ready for delivery
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Cold Air
275oC Air
Flue gas
Hot air 800oC to
the burners
Soda Lime Glass Furnace Recuperator 230 ton/day
The picture shows a tube bundle and double shell air preheating system for a container glass furnace with the productioncapacity of 230 ton/day and a preheating temperature of 800C.
GLASS CASE HISTORY:
The following example is taken from a big container glass furnace showing the short pay back time for the investment:
Furnace production 230 ton glass/day or 84 000 ton glass/year
Energy consumption 2600 kcal/kg glass (no airpreheating)
Oil consumption 0,27 kg oil/kg glass 22 750 ton oil/year
Exhaust temperature 1350C
Air preheat temp 800C
Fuel saving 45% or 10 235 ton oil /year
Oil price 200 USD/ton
Saving: 2,05 MUSD/year
Investment 1,3 MUSD
Lifetime 10 years (one campaign)
Pay back time 8 months!
Waste gas outlet temperature 800C
Air flow 17 400 Nm3/hr
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Double shell recuperator assembly
A tube bundle system under construction
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A steel air preheater prior to installation
OTHER APPLICATIONS - IRON ANDSTEEL
Edmestons long experience of radiant heat recoverysystems in the glass and carbon black industries is alsoused in applications for the iron and steel industries.
The figure illustrates the basic principle of the
recuperators:
The furnaces often work at combustion airtemperatures as low as 400C. Raising the airtemperature with 100C results in about 6% fuel savings.This substantially reduces the operating costs of thefurnace.
Several references are available.
Recuperators for billet reheating furnaces
25 MW input power and a furnace temperature of1000C. The furnace is heated by natural gas and opengas burners. The flow is cross-parallel.
Air preheat temperature 400-450C
Waste gas inlet temperature 810-975C
Waste gas outlet temperature 522-655
CAir flow 26000-38 000 Nm3/hr
Waste gas flow 27000-40000 Nm3/hr
The recuperator was installed 1992 and is still inoperation.
DRI (direct reduction of iron)
Air inlet temperature 190C
Air outlet temperature 650C
Waste gas inlet temperature 1070C
Waste gas outlet temperature 800C
Air flow 74 000 Nm3/hr
Watse gas flow 94 000 Nm3/hr
The recuperator saving gives a pay-off time less thanone year of the investment.
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Flue gas in
Hot air out
Flue gas out
Cold air in
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EDMESTON
www edmeston com
EDMESTON AB (Head Office)Olof Asklunds gata 8S-421 30 VSTRA FRLUNDA, SwedenTel: +46-31 335 63 50Fax: +46-31 335 63 65E-mail: [email protected]
EDMESTON USc/o Sandvik Process Systems LLCTotowa, NJ 07512USAE-mail: [email protected]
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