A key objective of Celanese is to drive energy efficiency and cost reduction in its plants. In line with this, the company has become a partner in the Better Plants Challenge of the U.S. Dept. of Energy.
One way to attain such benefits is to engage the entire operations organization in energy reduction. At Celanese, energy optimization historically was a management or engineering responsibility. However, we realized that process operators took care of real-time control of energy but usually weren’t actively optimizing consumption.
Celanese discovered that these operators, if given access to real-time information on energy consumption as well as targets for the key energy consumers, could optimize energy use in the plants more effectively.
As a result, the company created energy dashboards to provide operators with access to real-time energy consumption and dynamic energy target information — thus giving them appropriate knowledge and tools to reduce energy use. We’ve found these energy dashboards are a great way to get energy information into the hands of the people who can respond immediately.
Celanese implemented the first energy dashboard in 2013; now six sites have dashboards in place. We currently are working to roll out the dashboard concept to three more sites in 2017–18.
A large chemical plant’s energy systems are complex. The optimum ranges of process energy consumption change often, based on production rate and many other factors such as equipment use or product mix. The operators responsible for continuously monitoring the processes and process equipment sometimes are best positioned to make decisions and take immediate action on energy usage and optimization in their sections of the plant. Although Celanese plant operating personnel understood the importance of energy management, the existing control screens, i.e., the human/machine interfaces (HMIs), didn’t give them the level of information required to optimize energy in real time.
To improve this situation, Celanese upgraded the process control HMIs so the operators could get a better understanding of process energy flows and optimum energy targets in real time — and empowered them to take appropriate action to ensure the processes maximize energy efficiency and reliability.
Visualization was crucial for imparting better understanding, so we created energy dashboards. These provide a simple and continuous in-plant display of energy consumption and target ranges with the capability also to view the individual drivers that impact overall energy consumption.
The development of the energy dashboards included three main phases — evaluate, implement and sustain.
During the evaluate and implement phases, a cross-functional internal group of process engineers, operators, and six-sigma black belts collaborated to map the energy users and key drivers, analyze energy data, develop the energy models, and set up the dashboards in the plant. The six-sigma black belts leveraged their statistical expertise to do the statistical modeling that identified the process variables affecting energy consumption.
The plants already had in place the required equipment, supervisory control and data acquisition (SCADA), HMI and data historian systems as well as the necessary statistical software packages. All that was needed was to apply internal resources, including Celanese’s six-sigma and process experts.
Some of the relationships between energy and the processes weren’t readily apparent. So, the six-sigma experts collected feedback from engineers and operators. This enabled them to accurately model the key energy consumption drivers, establish the data collection protocols and statistical models, and develop the displays. Statistical modeling and regression of the key process inputs identified energy-consumption target ranges.
In the sustain phase, the operations teams developed a process to cover energy-related issues at shift-handoff and routine production meetings so that energy discussion became part of the regular cadence of plant operations. Leveraging existing meetings and systems ensured sustainability of the energy review and use of the dashboards. In addition, to share energy best practices in the plant, sites developed an operations energy playbook based on actions taken from the dashboard information.