Sand screening plants – gravel pits
SERVELECT has carried on power efficiency works in over 40 sand screening plants – gravel pits. Our experience and effects produced in reducing the consumption lead to the following conclusions:
- Most of the consumers in this field use low efficiency electrical installations and equipments ;
- The functioning period is seasonal, depending on the orders;
- When taking energetic efficiency measures, the consumptions drop with approximately 40%, even if the production activity is increased or preserved;
Results obtained under SERVELECT involvement:
• Most of the gravel pits have an individual transformer, and active and reactive losses occur; these losses are billed both during activity and stagnation periods; thus, during stagnation periods and despite the consumer’s lack of activity, he shall pay amounts varying between 1000 – 2500 RON for transformer losses;
• SERVELECT provides services for reactive losses compensation which substracts the reactive transformer losses from the bill;
• By choosing the optimal energy billing rate and observing the consumption timetables, the amounts to be paid drop with 5 – 20%;
• The compensation of the consumed inductive reactive energy eliminates the reactive energy costs from the bill; the power coefficient of a gravel pit is under 0,4 which leads to penalties of 3 times the usual price when paying the reactive energy!
• Mounting frequency drives on water pumps regulates the water flows and reduces water consumption (paid if taken from rivers); when adjusting the revolution, the electrical energy consumption drops up to 35%;
• Maintenance of electrical equipments: although the electrical engines are usually rewound, the disadvantage of this method is more than obvious; a rewound engine uses much energy, has bigger reactive losses, warms up more rapidly and takes higher maintenance costs in time;
• 20% of the costs of a new engine, with higher energetic performances, are covered by the price of recycling the old engine!
• The energetic performance difference at a 55 kW engine, from 87% at the old one, to 93% at the new one, 10-hour functioning daily, 100 days a year, leads to a 30% energy saving out of the new engine’s price, as amortization!
• If the process (conveyor belts) permits the mounting of frequency drives for engine monitored feeding, the revolution adjustment saves important electrical energy.
• The electrical distribution panels play an important part in feeding electrical engines as they comprise short circuit and overload protection. When the protection is faulty, the engines break down. SERVELECT ensures replacement of electrical engines, mounting of converters, replacement of electrical distribution panels and processes automation!
• Processes automation: the HMI SCADA interface controls the sand sorting process and prevents blockings, overloads on the conveyor belts or grinders by measuring the processed quantity of sands;
These statements are certified with the results obtained in different locations, case studies with calculation abstracts and energetic audit drafting!