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Värmeåtervinning av gruvventilationsluft - LKAB i Kiruna
Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
2011 (Swedish)Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesisAlternative title
Heat recovery of mine exhaust air - LKAB in Kiruna (English)
Abstract [sv]

For att brytning under jord ska vara mojlig maste stora mangder frisk luft pressas

ned till brytningsnivan, vilket gors fran olika gruvventilationsstationer. For att undvika

nedisning i schakten varms tilluften upp till 1

. innan luften transporteras ned

i berget. Idag sker denna uppvarmning av varmebatterier som nyttjar spillvarme

fran kulsinterverken. Finns ett extra varmebehov spetseldas det med olja.

Franluften ar fuktig och varm. Det ar darfor intressant att undersoka om det

skulle kunna vara mojligt att installera varmevaxling pa gruvventilationsstationerna

och nyttja varmen i franluften fran gruvan till att varma tilluften. Varmevaxlarsystem

som undersokningen grundar sig pa ar av typen batterivarmevaxlare.

Batteritillverkaren skickade ett forslag pa batterityp som skulle klara de krav

som stallts och en oert for detta system. Det system som valdes hade 4 tilluftsbatterier

av storleken 4500x2000 mm och 3 franluftsbatterier av storleken 8000x2200

mm. Varje tilluftsbatteri hade en dimensionerad eekt av 661 kW och varje franluftsbatteri

var dimensionerat till 882 kW.

Berakningar pa energibesparingen i olja som varmevaxlingen kunde medfora

gjordes. Dessutom raknades det ocksa pa hur mycket spillvarmesenergi som kunde

sparas genom att installera varmevaxling. Berakningarna genomfordes pa sammanlagt

9 gruvventilationsstationer, dels varje station for sig, dels om era stationer


Den energi som station 1arligen kunde bespara i olja var ungefar 4,7 GWh per

ar. Skulle varmevaxling installeras pa 9 stationer skulle energimangden insparad

olja bli ungefar 29 GWh per ar.

Den energi som kunde sparas in i station 1 i form av spillvarme var 0,6 GWh

per ar. Skulle varmevaxling installeras pa 9 stationer skulle den ersattningsbara

spillvarmen vara ungefar 18 GWh per ar.

De ekonomiska berakningarna gjordes i tva fall. Ett da berakningarna endast

byggde pa fortjansten av insparad olja och ett fall da det aven beraknades att den

insparade spillvarmen kunde saljas till TVAB.

Den totala installationskostnaden per station beraknades till cirka 4,3 miljoner

kr och vid berakning pa bara fortjanst av olja skulleaterbetalningstiden for 1 station

bli ungefar 1,4 ar. Med 9 stationer skulle aterbetalningstiden bli 3,6 ar.

Tas forsaljning av spillvarme med i beaktning och adderas till fortjansten av

olja sa blir aterbetalningstiden for 1 station anda 1,4 ar, men for installation pa 9

stationer blir aterbetalningstiden 2,4 ar.

De problem som skulle kunna uppsta ar problem med nedsmutsning, nagot som

skulle kunna forebyggas genom storre lamelldelning i batterivarmevaxlarna samt

skyddsmalning med Heresite pa franluftsbatterierna. Utbyggnad av franluftskanalen

maste ocksa goras da franluftsbatterierna ar for stora for att fa plats i den kanal

som nns idag.

Berakningarna bygger i alla stationer pa en franluftstemperarur pa 8

. och

en relativ fuktighet pa 100 procent. Samma sorts batterivarmevaxlare har alltsa

anvants i berakning av de olika stationerna. Vid en ytterligare projektering foreslas

att exakta varden for varje station skickas in till batteritillverkaren sa att stationsprecisa

batteriprestandakurvor kan beraknas fram.

Rekommendation ar att en forsta installation av varmevaxlarsystem genomf

ors pa KV10 da dar nns gott om plats nns for installation av tilluftsbatterier

samtidigt som den har nast hogst franluftstemperatur.

Abstract [en]

In order to make underground mining production, large amounts of outdoor air

must be pushed down to the mining level. At the LKAB facility in Kiruna this is

done by a number of mining ventilations stations. The air has to be heated before

it is transported down to the mining levels. This is done in order to prevent icing in

the shaft. Today, the heating of the air is done by using waste heat from the pellet

mills and if extra heating is needed, due to lower outdoor air temperatures, oil is


The exhaust air from the underground is moist and warm. It is therefore interesting

to investigate if it is possible to install a heat exchanger in the mine ventilation

stations and use the heat in the exhaust air to heat the supply air. The heat recovery

system which has been investigated in this study is a type of coil heat exchanger.

Heat exchanger manufacturer has submitted a proposal on the type of coil

heat exchanger that could withstand the specic demands and oer a price for the

system. The chosen heat recovery system has four supply exchangers with the size

4500x2000 mm and 3 exhaust exchangers with size 8000x2200 mm. Each Supply

air coil had a power of 661 kW and each exhaust exchanger was sized at 882 kW.

Analyses were made to estimate reductions in the use of oil by implementing

the heat recovery system. In addition, also the amount of waste heat energy that

could be saved by installing the heat exchangers was calculated. The calculations

were carried out on a total of 9 mining ventilation stations.

The energy that the rst installed station could save in form of oil during a

year has been estimated to 4,7 GWh. If heat exchangers were installed in all the 9

stations the energy reduction would be approximately 29 GWh per year.

The energy that could be saved at station 1 in the form of waste heat was 0.6

GWh per year. If heat exchangers were installed at all the 9 stations, the recoverable

waste heat was calculated to be approximately 18 GWh per year.

The nancial analyses were made for two cases. One that was based only on

prots from the saved oil and, the other also by selling of the saved waste heat to


The total installation cost per station was estimated at to around 4.3 million

skr. Considering the saved amount of oil the payback time for a single station was

found to be approximately 1.4 years. For all the 9 stations the payback time was

estimated to be 3.6 years.

If sale of waste heat is included and added to the analysis, the payback time

for a single ventilation station is 1,4 years and for an installation in all the stations

the payback time is 2,4 years.

The problems that could arise are due to contamination, which could be prevented

by greater spacing of the battery heat exchangers and protective coating

with Heresite. Expansion of the exhaust duct must also be made when the exhaust

air coils are too big to t in the available channel .

The calculations are based on the assumptions that the temperature of the

exhaust air is 8

. and the relative humidity is 100 % in all stations. The same

kind of coil heat exchanger has therefore been used in the calculation of the dierent

stations. In the next design step it is proposed that more accurate values for

each station are provided to the heat exchanger manufacturer to improve design

performance of the recovery system.

A futher recommendation is that the rst installation of the heat exchange

system should be implemented in ventilation station KV10 where there is plenty of

space available for a heat exchanger system, and KV10 also has the second highest

exhaust air temperature.

Place, publisher, year, edition, pages
2011. , p. 92
National Category
Energy Engineering
URN: urn:nbn:se:umu:diva-58990OAI:, id: diva2:550508
External cooperation
Educational program
Master of Science Programme in Energy Engineering
Available from: 2012-09-07 Created: 2012-09-07 Last updated: 2012-09-07Bibliographically approved

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