Energy
Energy Saving Initiatives - Rotating Equipment in all Industries
The first quarter of 2006 has seen an unprecedented increase in the cost of power in the UK. In some areas British industry has seen the cost of electricity rise from £24 to £63/megawatt hour.
For industry to survive, it has become imperative that prime mover power requirements used in manufacturing are drastically reduced to stem the flow of wasted energy. This does not mean that manufacturers have to reduce product output but simply to review and improve the efficiency of their equipment. Great savings are to be had in even the best run sites.
Historically, large amounts of equipment installed in UK industry was carried out when the economy was thriving 20 or 30 years ago and energy was relatively cheap. Little thought was given to plant efficiency and operational philosophy. Oversized pumping equipment was installed to ensure it met duty requirements with plenty of capacity to spare. In some instances boiler feed and cooling water pumps operated in parallel to safe guard failure to the system. This was both expensive in power and drastically reduced mean time between failure(MTBF) due to equipment operating well away from their best efficiency point (BEP).
Over the years, experience has shown that pump reliability and BEP operation often run hand in hand. Pump Supply & Repair Group has helped a number of its customers in this area. Please take a moment to review the following examples and select an area we may be able to help you with:
Power and Reliability Improvements
1) Paper Manufacturer- Lancashire, Boiler Feed Pumps
Boiler plant - 2 boilers operating @ 15 bar. Total evaporation load 35 T/hr.
The plant has 4 off Grundfos CRE 32-12 feed pumps. 3 duty and 1 standby.
Third pump operating as a running emergency back up in case one of the others fails in service and boiler plant is forced to shut down. All pumps are fitted with inverter drives but left operating at full speed (50 Hz). Delivery pressure in the feed main 20.7 bar. Total feed capacity available approaching 60 Tones/hour.
Observations/Issues
Pumps are expensive to run, unreliable and requiring a major overhaul every 12 months.
Solution
Following a site investigation, the duty pump requirements were reduced to 2 pumps operating at reduced speed and the 3rd unit was placed on emergency standby operated by a pressure switch in the feed main. This pump would only start if feed main pressure drop occurred. Duty pumps now operating around BEP improving MTBF.
Annual Energy savings:
Based on £24/mW hr. £9,900 - Based on £63/mW hr. £26,000
Savings on annual repairs: £3,600
2) Chemical Manufacturer - Warrington, Cheshire
Plant has total of 3 KSB WKF 65/11 duty of 45m^3/hr @ 440m. 1 duty/ 1 assist / 1 standby.
Observations/Issues
The boiler and steam drum pressure is 26 Bar G we are therefore reviewing the need for the pump to produce 440m discharge pressure. In conjunction with this point we are looking into the operation of the 3 pumps which currently run on a duty - assist - standby. The site also has a requirement at weekend for 5-10m^3/hr @ 440m
Solution
Following a site investigation the following options have been proposed,
- De-stage the units to give a revised discharge pressure of 32 Bar G. This would provide significant cost savings based on the revised power absorbed on the units. Also looking into the supply of EFF 1 motors to replace the existing motors
- As there are occasions when there is a requirement for two pumps running, PSRG are reviewing the options of fitting an inverter on the secondary pump to meet the demands should the first unit be unable to meet the system requirements.
- Currently the existing units are used to meet the weekend requirements which entail a large flow being sent down the bypass line. Given the low duty requirements a pump selected solely for this duty would have a pay back of approximately 8 months which would include the capital cost and the first year energy cost.
Annual Energy Savings: Proposal 1 £26,460, Proposal 2 £18,800, Proposal 3 £19,000
3) Power Station, Staffordshire
Liquid Ring Vacuum Pumps (LRVP) to maintain the condenser vacuum
Each turbine set has three LRVP units each operating continuously with a 150kw Drive
Observations/Issues
After carrying out on site performance tests it was identified certain pump were achieving poor vacuum and volume figures
Solution
The three pumps were removed in stages at shut down dates and were replaced on a service exchange program with pumps fully overhauled by PSRG and performance tested at our workshop. On re-installing the units on site it has been found that the client can achieve the required vacuum level with two pumps only. Client is now running two duty pumps and one on a standby basis saving both reduced energy and service liquid costs.(Water)
Annual Energy Savings: Energy - £96,000
4) Utility Company - Warrington, Cheshire
Service provider for water services undertaking a program of pump refurbishment incorporating energy improvements
Observations/Issues
A KSB 160 KW submersible unit was identified as being a significant user of energy and it was identified as requiring refurbishing incorporating energy saving initiatives.
Solution
One New Impeller was sourced and prepared by grit blasting, chemically treated to remove salt deposits within the steel, grit blasted to achieve the correct surface profile and two coats of Belzona 1341, Energy Efficient Supermetal Glide applied. The unique hydrophobic nature of the Belzona 1341 system makes water simply runs off. Wear by abrasion is minimized by its encapsulated blend of lubricating and abrasion resistant fillers. When applied to fluid flow equipment, Belzona 1341 can reduce power consumption, increase efficiency, lower maintenance costs, and improve hydrodynamic performance. Belzona 1341 is suitable for contact with potable water. It is certified to ANSI/NSF Standard 61, and satisfies the U.K. Drinking water inspectorate requirements.
Annual Energy Savings: Currently being measured. Normally in the region of 4-5% of power consumption
5) Power Station - Dartford, Kent
Contract to undertake the repair of various pumps at the Power Station
Observations/Issues
Part of the establishment of scope of work of the job specification included discussions with PSRG addressing 1) The build up of scale on pump internals, 2) Applying an energy efficient coating. Previously pumps had to be chemically treated in situ to eradicate the limescale, however the chemical attacked the parent metal which shortened the life of the pump and reduced the performance.
Solution
PSRG proposed the application of Belzona 1341 Supermetal Glide which has been proven to minimise the build up of limescale and has excellent energy efficient properties. The unique hydrophobic nature of the Belzona 1341 system makes water simply roll off. Wear by abrasion is minimized by its encapsulated blend of lubricating and abrasion resistant filler. When applied to fluid flow equipment, Belzona 1341 can reduce power consumption, increase efficiency, lower maintenance costs, and improve hydrodynamic performance. Belzona 1341 is suitable for contact with potable water. It is certified to ANSI/NSF Standard 61.
Annual Energy Savings: Currently being measured. Normally in the region of 4-5% of power consumption
Asset Management
PSRG offer the customer total pump management. Using our own in house tracker system, PSRG can provide a customer with invaluable information identifying poor performing pumps or pump locations with high failure rates. Common causes of failure such as bearings, mechanical seal, erosion, cavitation, dry running etc. are also highlighted to the customer and an agreed programme of improvement implemented to increase the Mean Time Between Failure, which in turn increases plant availability and the customer's profitability.
Site surveys are also offered to identify pumps which may be obsolete and therefore affect the pump's turnaround time due to spares availability thus causing unnecessary plant downtime. This service will also identify assets which may have been installed in a manner which is detrimental to the performance thus causing premature failure. An additional benefit of the survey is to highlight Energy Savings which may be achieved through Variable Speed Drive, Efficiency Coating, etc.
From the customer historical information and the information gathered through the survey PSRG can then submit a proposal for Condition Monitoring focusing on the critical assets whether that be Health & Safety, Production or Repair Cost.
