Cross Cutting Technology

A number of cross-cutting systems, such as steam, compressed air, fan and pump, systems are commonly operational in iron and steel mills. A number of measures can be implemented in order to assure optimal performance of these systems and thereby save energy. Some of the common measures are provided in this section.

Cross Cutting TechnologyTechnologies & Measures

Technology or MeasureEnergy Savings PotentialCO2 Emission Reduction Potential Based on LiteratureCostsDevelopment Status
Preventive and Predictive Maintenance

Several estimates US flag  Preventive maintenance is estimated to reduce fuel consumption by 0.09 GJ/t-product and electricity consumption by 0.05 GJ/t-product.

US flag  Emissions reductions are estimated to be around 15 g CO2/t-product.

Annual operating and retrofit costs are estimated to be 0.03/t-product and $0.02/t-product, respectively.

Energy Monitoring and Management System

An additional 0.5% improvement in overall energy efficiency can be realized.
Fuel and electricity savings are estimated to be in the range of 0.02 and 0.01 GJ/t-product.

Emission reduction potential is estimated to be 3.7 kg CO2/t-product.

Retrofit capital costs are $0.23/t-product.

Software Tools to Boost Steam System Efficiency

US flag Cumulative energy savings of around 20130 TJ/y have been enabled in various plants with the use of these tools.

US flag Approximately 1.5 million tons of CO2/y savings have been realized with the use of such tools.

US flag  Use of these tools have enabled cumulative savings in excess of US $101 million/y in various plants.

Process Heating Assessment and Survey Tool

With the use of this tool, various alternatives resulting in 39 GJ/h savings have been identified for a reheating furnace

US flag  Cumulative annual energy savings of 5270 TJ/y have been realized with the use of this tool

US flag In the US, cumulative emission reductions of 273 640 t-CO2/y have been realized with the help of this tool.

US flag Cumulative cost savings of around US $39 million/y have been realized with the use of this tool.

Insulation of Steam Lines

Insulation can typically reduce energy losses by 90%.

US flag Payback times between 10 to 13 months have been reported In one steel plant it was found that for every 100 feet of piping insulated, energy savings could be upto $19,000 each year (Worrell, et al., 2010. p. 52).

Checking and Monitoring Steam Traps

Energy savings for a regular system of steam trap checks and follow-up maintenance is estimated to be up to 10%

Using automatic monitoring it is estimated that an additional 5% cost over steam trap maintenance can be saved, with a payback time of 9 months.

Recovery of Flash Steam

Depending on the pressures involved, the flash steam contains approximately 10% to 40% of the energy content of the original condensate.

The economics of heat recovery projects are most favorable when the waste steam heat content is high and the flow is continuous. Average payback time for this measure is around 9 months.

Motor Maintenance

The savings associated with an ongoing motor maintenance program could range from 2% to 30% of total motor system energy use.

Variable Speed Drives on Flue Gas Control, Pumps and Fans

US flag  Energy saving potential is estimated to be 0.02GJ/t-product (US EPA, 2010)
Electricity savings are estimated to be between 20 – 50% of pump energy consumption (Worrell, et al., 2010. p. 64).

EU Flag A plant in Germany saved 3.2 GWh/y and 325 GWh/y with the installation of VSDs (IPPC, 2009). 

Implementation costs are estimated between $1.3/t-product (APP, 2010) to $2.0/t-product.

EU Flag  Investment costs for the German plant was €67 thousand. It provided annual savings of €32.5 thousand, giving a payback time of 2.1 years, and a RoI of 48%. (IPPC, 2009)

Fan System Assessment Tool

US flag Cumulative annual energy savings of 52.8 TJ/y have been realized with the use of this tool.

US flag Cumulative COsavings of 3022 t-CO2/y have been realized with the help of this tool.

US flag Cumulative cost savings of around US $346 thousand/y have been realized with the use of this tool.

Proper Fan Sizing

US flag  In one plant installation of a smaller vent blower resulted in electricity savings of 896 MWh/y.

US flag The smaller fan system enabled cost savings of $35,840/y and had a payback time of 5 months.

Efficient Pumps and Motors

Replacing a pump with a new efficient one reduces the energy use by 2% to 10%.
Higher efficiency motors have been shown to increase the efficiency of the pump system by 2 to 5%.

For a given duty, a pump that runs at the highest speed suitable for the application will generally be the most efficient option with the lowest initial cost.

Proper Pump Sizing

Correcting pump oversizing can save 15% to 25% of electricity consumption for pumping on average for the U.S. Industry.

Multiple Pumps for Varying Loads

In a pulp and paper plant, installation of a smaller pump (pony pum) reduced the overall energy consumption of the pumping system by 58%.
The Installation of parallel systems for highly variable loads on average would save 10% to 50% of the Electricity consumption for pumping for the U.S. Industry.

Impeller Trimming

By reducing the impeller diameter from 320 mm to 280 mm, energy savings between 25 to 30% have been realized in plants in the US and the UK.

Maintenance costs were reduced by impeller trimming.

Precision Castings, Surface Coatings or Polishing

Energy savings are 36 MWh (or 2%) per year.

Additional cost of coating would be paid back in 5 months.

Auditory Rotary Machines for Pump Efficiency

Energy savings depend on how the pumps are operated.  A reduction of 20-30% in electricity use is estimated.

$63,000-$65,000/year reduction in power costs.

AIRMaster+ Software Tool for Improved Compressed Air System Performance

US flag This tool has helped realize cumulative savings of 992 TJ/y in various plants in the US.

US flag Cumulative emission reductions are estimated at 55 thousand tonnes of CO2/y.

US flag Cumulative cost savings in excess of US $5 million/y have been realized with the help of this tool.