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Energy Conservation
Tips on Steel re-rolling mill |
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| Furnace : |
- Control Excess air with oxygen at 3% level in flue gases.
A 10% drop in excess air amounts to 1% saving of fuel in
furnaces. For an annual consumption of 1000 kilo liters
of furnace oil, means a saving of over Rs. 1 lac.
- Normally flue gas temperature is beyond 5500C. To recover
waste heat install recuperator of required capacity.
- Install missing doors of the furnace and ensure sealing
to avoid radiation losses.
- Do not heat stock on visual inspection basis. Install
temperature instruments to control furnace temperature at
soaking and heating zones in order to achieve.
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a. Fuel saving.
b. Reduction in scale loss.
c. Eliminate probability of total material rejection.
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- Put cap on burner block holes after removing the burner
if not in use. This will avoid ingress of excess air.
- Install Flow meters and pressure gauges at furnace oil
service tank exit.
- Hire a suitable flue gas analyzer and check all the parameters
at least once in a month for proper combustion in the furnace.
Ideally once a batch.
- Close furnace doors properly after charging the blooms
into the furnace.
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| Insulation : |
- Improve insulation & refractory of the furnace. Re-line
the doors and insulate hot lines also.
- Insulate valves and flanges to minimize the heat loss.
Insulation is to be of boxed type for maintenance ease.
Observation shows that a furnace operating at a temperature
of 10000C and keep its doors open results in a fuel loss
of 1 Ltr./hr. For a 1000 hrs. furnace operation this translates
into a loss of approx Rs. 1 Lac per year.
- Improve insulation if the surface temperature exceeds
600C. Ensure that proper insulating material and thickness
is provided for proper insulation.
- Arrange or ask for Industrial training programme on refractories
in your cluster once in a year.
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| Recuperator : |
- · Overhaul the recuperator of re-heating furnace
at regular intervals to ensure recovery from flue gases
and improve the combustion. Ideally once in six months.
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| Fuel Handling and Operation : |
- For efficient combustion pre-heat the oil to have temp
between 1050-1100C at burner tip and optimize air to fuel
ratio.
- To stop abrasive particles FO filtration system should
have filter mesh sizes as follows.
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a. Between Lorry & main storage tank-mesh size 10
b. Between service tank & pre-heater- mesh size 40
c. Between pre-heater and burner- mesh size 100
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- Provide water draining facility and regularly drain water.
This reduces sludge formation and other problems like erosion
of burners and damage to the refractories.
- It is preferred to have parallel FO pumps of smaller
capacity than one pump of larger capacity to avoid unnecessary
re-circulation of huge quantity of FO.
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| Burners : |
- Use thin film burners in place of conventional burners.
Burners should be dismantled and cleaned frequently, preferably
once in a shift. Good thin film burners have been developed
by PCRA & IIP Dehradun which increases energy transfer
from primary air to fuel oil to 70%.
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| Flue Gases : |
| · Use high temperature flue gas to increase the stock
temperature from 4500 upto 7000C before entering the dryer.
This decreases the process time and increases production. |
Power Factor :
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- Improve power factor by regular checking of current of
all the capacitors and their timely replacement.
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Motors :
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- Avoid idle running of rolling mill motors & fans.
- Provide canopy on all outdoor motors.
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Lighting : |
- Replace 40W Tube light by slim 28W Tube light and electromagnetic
choke with electronic choke.
- Replace 400 Watt Mercury Vapour lamps with 250 Watt sodium
vapour lamps or 250 W metal hallide lamps.
- Replace 250 Watt Mercury Vapour lamps with 150 Watt sodium
vapour lamps or 150 W metal hallide lamps.
- Provide more transparent sheet instead of asbestos sheets
to use natural light.
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| Contract Demand : |
- Provide demand controller with an alarm provision in
case it exceeds contracted demand.
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General
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- Wherever possible try to produce particular type of product
for longer period. This increases productivity.
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