Client Reported
Upon introduction of the AWC800 thermoset polymer seal in place of the local urethane seal, shrinking has now been totally prevented. Metal-to-metal wear between the ram and barrel is also restricted due to the introduction of wear bands. Instead of shutting down 3 times per milling season, the cylinder lasts for five seasons without leaking.
- 4th mill – (1st repair) – lasted from 2007 – 2012, that’s equivalent to 5 milling seasons
- 4th mill – (2nd repair) – lasted from 2012 – present (cylinder isn’t leaking yet, reconditioning is done only for preventive maintenance), that’s 7 milling seasons and still counting.
- 1st mill and 2nd mill – (1st repair) – lasted from 2008 – 2017 (cylinder isn’t leaking yet, reconditioning is done only for preventive maintenance), that’s 9 milling seasons
- 3rd mill – (1st repair) – lasted from 2011 – 2016 (the main reason of reconditioning is not the quality of seal but the mechanical problem on the equipment that affects the rest of the parts of the equipment).
- 3rd mill – (2nd repair) – lasted from 2016 – present, that’s 4 milling seasons and still counting.
- 1st and 2nd mill – (2nd repair) – lasted from 2017 – present, that’s 2 milling seasons and still counting.
ROI
(1) Resealing Cost Savings
Under their old design, resealing costs per mill jack is Php. 16,000, multiplied by 2 (one roller: 2 cylinder), then multiplied by 3 (3 shutdowns), this would incur a total of Php. 96,000 cost/milling season.
The upgraded design provided by Piesco Hydraulics during 2007 cost Php. 280,000 however it lasted (without leaking) for 5 full milling seasons. Even then, the seals were replaced for preventive maintenance only (cylinder did not leak).
5 milling season seal cost (original design) = Php. 480,000
5 milling season seal cost (upgraded design) = Php. 280,000
Total Seal Cost Savings for 5 years (5 milling seasons) = Php. 200,000*
* savings from prevention of hydraulic oil loss, prevention of production loss from downtime, and savings from efficient extraction not yet included
(2) Savings from Prevention of Production Loss
Scenario A) Assuming that the operator chose to by-pass one of the roller systems, this will result in a lower percentage of juice extracted compared to a roller system with all the rollers operating. In this case, the average extraction loss% is 4.25%.
One ton of sugar cane = 85 kg of sugar produced; Sugar price = Php. 900.00 for 50 kg.
Milling speed = 200 tons of sugar cane/hour makes approx. 17,000 kg of sugar per hour.
4.25% of 17,000 kg = 722.5 kg per hour loss.
722.5 kg at Php. 900 / 50 kg = Php. 13,005 per hour loss.
12 hours per day, 150 days per standard milling season = Php. 23,409,000 production loss per season.
Scenario B) Assuming that the operator chose to stop production and have the seal repaired. The replacement takes 24 hours to undertake. Breakdown occurs three times per milling season. Therefore 72 hours of lost production per season.
One ton of sugar cane = 85 kg of sugar produced; Sugar price = Php. 900.00 for 50 kg.
Milling speed = 200 tons of sugar cane/hour makes approx. 17,000 kg of sugar per hour.
72 hours x 17,000 kg = 1,224,000 kg lost production per milling season = Php. 22,032,000
(3) Hydraulic Oil Cost Savings
Under Scenario A), the operator continues to allow hydraulic oil to leak until the next scheduled service, the resultant wastage amounts to several drums worth of lost oil and therefore prove very expensive. It was calculated that the loss of oil rate was around 2.5 ltr per hour of operation. As previously stated, the milling season is approx. 1,800 hours. Oil leaking rate = 20 liters / 8 hours = 2.5 liters / hour x 1800 hrs = 4,500 liters.
- One hydraulic oil 210 ltr drum cost = Php. 15,000
- Therefore, total savings per milling season is Php. 321,428 (Php. 15,000 x 4,500/ 210)
- This does not take into account the additional process required to remove the leaked oil from the juice process
(4) Savings from Effective Extraction
Under Scenario A) or B), the inefficient performance of mill jack/cylinders results in poor extraction. This is because insufficient press loading from the leaking mill jack would not force the required and expected amount of juice to be extracted per sugarcane batch.
The very first repair done by Piesco Hydraulics was on the Mill Jack Cylinders (2 units) of the 4th roller of Tandem B. The 4th roller is critical as it does the final and finishing juice extraction operation.
Piesco Hydraulics improved the performance of 4th roller mill jacks which then resulted in efficient extraction. Because the improvement was recognized as substantial, they also assigned the repair of the remaining 1st, 2nd and 3rd roller to Piesco Hydraulics on the following years.
(5) Effi
cient extraction = Dry bagasse to feed the boiler
The efficient extraction of the juice from the sugar cane will leave behind dry bagasse.
Dry bagasse can be used as fuel to heat the boiler. If the bagasse is too wet (the juice is not entirely extracted), there are two possible actions:
- subjecting the wet bagasse to a separate dewatering process, or
- directly using the wet bagasse to heat the boiler and add bunker fuel for effective combustion.
The installation of another dewatering station and the use of more fuel for bunkers entail additional costs for the plant. For this reason, the bagasse must be already sufficiently dry as it passes through the last roller mill. Piesco has been able to improve the performance of its roller mills, and the resulting bagasse is already sufficiently dry as fuel. Therefore no further dewatering costs or fuel for bunkers are required.
Repair of other rollers
Given the remarkable improvement and cost-saving using Chesterton thermoset polyurethane seals distributed and installed by Piesco Hydraulics Philippines, the customer decided to handover the complete set of roller mills for future upgrades and on-going repair.
