Energy efficiency is one of the key elements of the IPPC Directive and is an important aspect when considering the options in Best Available Techniques (BAT).
The energy demand in certain process systems can be a huge component of the total costs of operating the plant. For example, some pumping systems may account for over 25% of the total energy usage on certain industrial installations. Yet, initial procurement and installation costs are used widely as the primary criteria for equipment or system selection, despite the fact that the initial purchase price of a piece of equipment may be insignificant when compared with the total lifetime operating cost. Under these circumstances, procurement and installation costs in isolation may be simple to use, but will lead to poor long-term decisions!
This is where life-cycle cost (LCC) analysis can be a valuable management tool to help maximise capital investment and plant efficiency.
The life cycle cost of a piece of equipment is the total "lifetime" cost to purchase, install, operate, maintain and dispose of the item. LCC analysis is a useful comparative tool between a series of technology or operating alternatives and can indicate the most cost-effective solution, in order that the least long term cost of ownership can be achieved.
Components of such an LCC analysis include usually initial purchase costs, installation and commissioning costs, operating costs (including energy costs), environmental costs, maintenance costs, decommissioning and disposal costs. LCC uses net present value (NPV) concepts, which consider discount factors, cash flow and time. Consideration must be given to whenever costs occur during the life cycle of the equipment or project, while statistical equipment failure rates add further economic reality.
For more information on life-cycle cost analysis, please refer to, for example, www.barringer1.com/lcc.htm
A number of LCC analysis tools exist and the methodology can be a very complex process. For this reason, the ESA and FSA Mechanical Seals Divisions have developed a simple, generic LCC software tool, specifically for sealing technology in rotating equipment (theSeal Life-Cycle Cost Estimator). This tool allows you to estimate life-cycle costs for sealing solutions on a comparative basis to assist in decision-making when specifying capital projects or upgrading existing rotating equipment technology.
You may compare up to 3 scenarios using a variety of arrangements including single seals, dual seals, single seals with dry-running secondary containment, non-contacting gas seals, compression packing, and sealless pumps. Most of the fields have been pre-loaded with default values, but you may over-write any of these at any time without adverse effect on the calculations.
LCC will be influenced of course by the reliability of the selected sealing solution. You are encouraged to think carefully about the individual MTBR values that are most appropriate for each scenario, and if necessary contact your mechanical seal, packing, or pump supplier for guidance.
Energy can be a large component of LCC. In the case of Mechanical Seals and Packings, the energy calculated is that of the seal or packing only, not the equipment in which it is installed. In the case of Sealless Pumps, the energy calculated is NET of the energy consumed by an equivalent piece of conventionally sealed equipment. Thus, the Sealless Pump LCC result is not the entire cost, but it is comparative to the Seals and Packing LCC.
The spreadsheet for the Seal Life-Cycle Cost Estimator is available at the following location on the FSA web site:
You can save the spreadsheet to your computer to use "locally" for additional analyses. However, please return to the site regularly to take advantage of refinements and improvements made to the Life Cycle Cost Estimator over time.