As part of our diverse activity in risk engineering, the Department Manager investigated and discovered that using the same technique with which we analyze processes to answer the question “is it safe?”, we can analyze processes to answer the question “is it efficient?”.
Through this new perspective we examine how the control system and the operators in the control room and on the field manage the process and suggest optimal methods for effective energetic management of the process.
Assimilation of economic analysis within the process effectiveness analysis, enables us to identify the optimal route through which to execute the production process by:
- Saving – saving electricity and resources such as fuel for transportation.
- Returning energy – using residual energy, returning within a process (such as heat replacements between feeding and exiting a refinement tower).
- Green planning – using the planning to reduce energy consumption.
- Economic fuel – transitioning to cheaper fuel.
In effect, at an energy consuming plant there are a number of systems for creation and supply of energy that exist concurrently. Some of them operate around the clock, others operate intermittently and other production units only operate as backup.
The energy control system ensures that:
- An operation regime is designed to operate the energy production units so that the cost is as low as possible.
- In routine operation and without faults, the energy production system operates as planned in optimal economic effectiveness as much as possible under the environmental regulation.
- During a fault the operation regime changes its goal to business survivability, meaning the duty to supply energy for continued production trumps over the efficiency considerations and sometimes even environmental considerations.
From this we can conclude that the more we can prevent and reduce faults and the more we can shorten their duration (dead time) we will earn energetic efficiency.
Energy control analysis
Using the statistical tools of risk engineering, and presenting the failure ways through incident trees and faults trees, enables identification of the root causes for each scenario and suggesting solutions.
- Improving reliability of instruments – easy to suggest and expensive to execute a comprehensive increase in the SIL value (an accepted index for instrument reliability). Correct analysis of the root causes for a failure enables focusing the treatment to the critical points.
- Redundancy – correct planning of redundancy directs and routes the operation regime to the desired alternatives.
- Preventive maintenance to critical equipment – equipment reliability can be significantly improved by conducting maintenance within the MTBF (Mean Time Between Failures) window. Correct planning of critical equipment maintenance enables improvement of energetic efficiency for practically free.
Scenario example: faults to temperature control at a spray water temperature controller
We identified that a single thermometer at a spray water temperature controller is responsible for the facility working at low efficiency for 15 days per year on average.
Improving the redundancy of the said thermometer will reduce the likelihood for a fault and the timeframe for identifying the fault so that the average disturbance time will decrease to half a day per year, and reduce the need to use a more expensive electricity system (Israel Electric Corporation instead of self-production).
|Down time before
|Down time after