Securing funding for your pilot plant can often be the most difficult obstacle to overcome when scaling up your process technology. While a pilot plant generally serves as a key stepping stone in taking a process from bench scale to full production, there usually still is strong pressure to minimize its cost. However, by skimping too much on the funding, you may build a pilot unit that does not give enough useful data for the construction of a production plant.
On the other hand, keeping costs reasonable could make the difference between your project getting cancelled or delayed due to capital restraints and smoothly moving through the capital approval process. This article will cover eight factors to consider when determining areas for cutting costs while developing your pilot plant.
Always keep in mind the goals of your particular project when considering this list. These factors often involve tradeoffs. Having a clear priority on what outcomes you need will determine which areas you can re-evaluate and which are set in stone.
Evaluating Pilot Plant Costs
To get a better handle on the potential costs of your pilot plant, review your project and assess each of the following factors:
1. Operating cost. Can you shift capital cost to operating cost? Because a pilot plant is a temporary operation, you could get by with less automation and more manual operator intervention. This can significantly reduce both instrumentation and equipment cost but might demand more attention from operators to keep the pilot plant running. Just be careful not to sacrifice the robustness of your overall system. People can be inconsistent and potentially can act as a new source of process upsets, increased transient states, or required startups and shutdowns.
For example, imagine a production-scale plant will be processing 120 mt/day of a dry flowable bulk solid. At production levels, this will require extensive solids-handling equipment including truck unloading, silos and conveyance. However, at a pilot level, you probably wouldn’t need full-scale solids-handling equipment and might get by with an operator with a shovel. Often solids-handling issues are well understood and so reducing equipment and using labor can save money with little risk. In a full-scale facility, solid handling isn’t trivial and still can pose unwelcome surprises. For tips about dealing with solids, see CP’s Solid Advice column. Purchase smaller, less expensive equipment to fully vet the technology or, depending upon run time, it might make sense to have an operator manually load a hopper.
2. Required production rates. When deciding upon the production rate of your pilot plant, you must strike a balance between cost and accuracy. Will your pilot plant reflect operating conditions of full production and to what degree? A 1,000:1 difference between production and pilot rates is too big to give much confidence in most situations. A 2:1 ratio provides an immense amount of confidence but would be a waste of money. Good engineering judgment and cost/benefit analysis are critical when making this choice.
It’s wise to keep in mind areas where a professional can assist. Knowing which unit operations are most likely to change with scale and how to combat this is key. For instance, if you have a packed-bed reactor with a heat-transfer jacket, a smart decision would be to choose a defined tube diameter and length. You would then use your pilot plant to vet this fixed tube diameter and length with a single large tube. The full-size production scale might require 150 tubes, but each individually should function exactly like the one in the pilot plant. This will give everyone involved a high confidence around the reactor.
3. Materials of construction. You might be able to economize by using a material that has a “good” or “fair” rating, based upon the particulars of your process and how long the pilot plant needs to run. The best way to confidently make this call before building the pilot plant is via coupon testing at lab scale.
Additional coupon testing in your pilot plant for production-grade equipment can also contribute to long-term savings. This helps ensure that any materials tradeoffs you might be considering won’t raise glaring issues. Nearly identical materials can lead to drastically different outcomes.