We recently completed a detailed evaluation of EPS pickling and acid pickling capital costs and are sharing the results with you in this EPS Update. When examining all components of capital costs – equipment, facility, installation – the evaluation shows that a tension-leveling EPS Coil Line project costs roughly 30% less than a push-pull, tension-leveling acid pickling line project of comparable capacity.
COMPARISON BASIS: OUTPUT
A valid comparison of EPS and acid pickling capital costs rests on the assumption of comparable output. For EPS, we can accurately model output using both the EPS Operating Cost Calulator and experience from our own EPS production line. However, we have no such tool to model acid pickling – we needed actual operating data from an acid pickler. Fortunately, some acid picklers were willing to share such data with us in the context of their evaluating EPS technology as a better solution for pickling AHSS grades.
In reviewing the data, a specific acid pickle line utilizing four acid tanks and running low carbon strip offered the most detailed cost information. We characterize this line as ‘service center duty’ because, among other reasons, it does not include a tension leveler. This acid pickle line is located in North America and was supplied from a very reputable acid pickle line equipment manufacturer. Using the data on average product (thickness and width) and tons this acid line actually processes, we found, based on our experience operating our own EPS tension level coil line, that a 2 Cell EPS Coil Line is a close match in output. This gave us the solid basis for the comparison we were seeking.
COST FACTOR 1: EQUIPMENT
| While the selected acid pickling line doesn’t include a tension leveler, it is a full-featured line. Like the standard EPS Coil Line, it does not use an in-line welder or stitcher to join coil ends. The cost data showed its total equipment cost is comparable to the 2 Cell EPS Coil Line, however, that lack of tension leveling is an important difference that keeps this from being an ‘apples-to-apples’ comparison. |  |
The EPS Coil Line is a full tension line with a tension leveler: EPS is a ‘tight line’ process so its uncoiler and recoiler provide the same overall tension as the entry and exit bridle rolls of the tension leveler found in acid pickling lines. By contrast, the four tank acid pickling line of this study featured just a basic flattener with no tension leveling at all. Therefore, to keep the lines on an equal footing, the cost of a bridle roll tension leveling system (customary for a line like this) was added to the cost of the acid pickling line. That adjustment escalates the total cost of the acid pickling line such that the 2 Cell EPS Coil Line equipment cost is 25% less than the adjusted acid pickling line equipment cost.
COST FACTOR 2: BUILDING
This factor is straightforward: it’s simply the footprint of each pickling line. The drawing of the acid pickling line indicates the crane-served area of the line is 313 ft. x 80 ft. for a total area of 25,040 sq.ft. The comparable numbers for the two cell EPS Coil Line are 165 ft. X 75 ft. = 12,375 sq.ft. Yes, there is more to the building than the uncoiler-to-recoiler sections of the lines. There are line services that do not have to be ‘under crane ’ like acid regeneration and EPS water filtration. But such areas are essentially equivalent in size since the two lines have equivalent output.
So the important difference is 25,040 sq.ft. for acid and 12,375 sq.ft. for EPS: the acid pickling line requires 2X the under crane space as the EPS line does, so it has 2X the building cost. At a building cost of $100/sq.ft. (a reasonable number for an industrial building with foundations, columns and rails to support 50 ton cranes), that is a difference of $1,266,500 more for an acid pickling line.
 | COST FACTOR 3: INSTALLATION When it comes to installation costs, we are very confident of the EPS Coil Line cost data. After all, we’ve just recently installed a tension leveled EPS coil line in our own facility and have been involved in many more installations at customer sites. We were not as confident about the acid pickling line scope, but we got valuable help from those same acid picklers. |
Bottom Line: an EPS line costs approximately 30% less to install than an acid pickling line of comparable output. That difference is easy to understand, because the acid pickling line simply has more components to be installed and connected plus the acid pickling line is almost twice as long. The acid line has separate pre-wash and post-wash systems that the EPS line doesn’t, plus the bridle rolls for tension leveling. The acid line has heaters, scrubbers, fume extraction systems, plus many more sets of pinch rolls that are not needed for EPS. And finally, there is just more plumbing – valves, piping, filters, etc. – needed for an acid pickling line. The cost of installing all this additional acid pickling equipment really adds up.
SUMMARY
For pickling of low carbon coils up to 0.250”, EPS has the cost advantage over a tension-leveling push-pull acid pickling line of comparable capacity in each category:
- 25% lower equipment cost
- 30% lower installation cost
- A $1.27 million savings in building cost
Combining these factors together, the EPS line capital cost is roughly 70% of the acid pickling line costs. If you introduce high carbon, alloy steels, AHSS and silicon steels into the mix, the EPS capital cost advantage becomes even greater. Why? Because while the EPS line’s output would be lowered modestly for these grades, the acid pickling line’s output would drop dramatically (see details). To raise the acid line’s output back to parity would necessitate additional acid tanks, more building space and greater installation costs, while the EPS’s equipment cost would increase only marginally.
For more details of the study, please contact Chris Liefer at 618-282-4200 xt 103 or by email.