Feature

Accelerating from Day One

Posted on 01 February, 2010 | Tags: Operation Optimization

Refineries and petrochemicals plants are facing many challenges in these very uncertain times. While many companies are reducing or deferring capital expenditures, all companies are trying to ensure that available capital is spent effectively, that operational readiness is achieved as quickly as possible, and that full production is sustained. This article is focused on key technologies that can accelerate the design, start up and sustained safe operation of process units to improve operational readiness from day one

 

The traditional approach to bringing a new unit online often relies on a phase where design and operational deficiencies are addressed during initial operation. This typically leads to a costly, prolonged and unstable startup that defers operating profits for long periods of time and which can ultimately have a significant financial impact. It also increases the vulnerability of the  plant to incidents during startup and initial operation. Often, technologies, which are critical for optimizing the performance of the plant, such as advanced process control, are not even contemplated until many months or years after initial startup.
There is a new approach, which is focused on achieving operational readiness and faultless startup. This approach takes advantage of design, construction  and training best practices and focuses on a smooth handover from the engineering contractor to the owner/ operator as a critical success factor.
Best practice suggests the formation of a cross functional Capability Development Team. This team must focus on unique technologies and knowledge to prepare plant assets for initial and sustained operation. A clear understanding of the process behavior is critical to the process and equipment design, control system design and the definition of plant operating procedures. Increasingly, technology is being used throughout the plant lifecycle to facilitate knowledge capture and transfer, including safety and reliability considerations.
A key element to operational readiness is handling infrequent and abnormal operating conditions effectively. This is of particular concern in starting up a new unit. The Abnormal Situation Management (ASM) consortium has been studying these issues for over a decade and provides best practices, guidelines and technologies for improving the operator's ability to correctly identify and respond to a variety of situations. The goal of the Honeywell led consortium is to reduce unplanned outages and process variability that decrease profits and increase the risk to plant employees and local communities.

Design Readiness
During the plant design phase, members of the Capability Development Team use engineering tools (such as process simulators) to develop the project requirements, process layout, equipment design, control system strategy, operating strategy, safety strategy, schedule, purchasing plan and capital cost estimates. A cohesive suite of integrated engineering and data management tools enable a consistent engineering workflow and plant design process to ensure alignment between the stakeholders in the decision making process. Considering that 60% of capital investments are made during the early project phases, engineering tools that create plant simulation models will have a positive economic impact on critical decisions that drive the project cost and schedule. The opportunities for process enhancement and project improvement decay rapidly with time in this phase as capital investments are committed to purchasing and construction.

Capital Cost Optimisation
In plant design, steady state process simulation is used to evaluate various operating scenarios to solve equipment-rating problems. The benefits include minimised capital expenditures while minimising process bottlenecks. Dynamic simulation is another well accepted tool because of the positive economic impact it can have on capital cost decisions.

Control System Development
The automation system is a critical way to the process and is key to the operator's success in meeting operating objectives and avoiding plant upsets. Simulation helps create realistic operating scenarios that enable engineers to assess the system configuration under dynamic conditions rather than the traditional method of static checkout. In this way, engineers can assess the ability of

• Graphics using ASM guidelines to present a clear picture of the process.
• Alarms to effectively bring the operator's attention to a potential upset.
• Regulatory controls to maintain the plant within its operating envelope increasing reliability.
• Safety systems to protect the plant from straying outside safe bounds of operation.

Procedure Development
The operator-training simulator can also be used as a platform for developing operating procedures. Operator actions captured during the simulated startup document the sequence of tasks that need to be performed when the plant goes online and can be improved with repeated simulation trials. This sequence can then be automated using procedural operations tools to improve the consistency of executing procedures.
In summary, the use of these technologies mitigates project risks, delays and the heavy cost of onsite resolution. Simulation also optimises committed capital costs and accelerates the initial plant startup, resulting in earlier profit recognition.

Operational Readiness
The ASM consortium reports that 40 percent of unscheduled shutdowns are caused by human error. In most cases, these abnormal situations could have been prevented if people had the knowledge, skills and confidence to respond quickly in an emergency situation. This research highlights the need for training as a critical investment to achieve a flawless start up and maintain best in class reliability. In the process industries, managers cannot afford to let staff 'learn from their mistakes.' Errors can cost production, revenue and even lives.

Operator Training Simulators
A key technology to enable this learning is an effective and comprehensive operator training simulator that accurately reproduces plant behaviours. This enables operators to interact with the 'process' without the fear of 'breaking something' and helps employees make well informed decisions by preparing them ahead of time through hands on training. Dynamic simulators are critical to educating trainees to the behaviour of the plant and learn how best to respond to various operating scenarios.
In addition to helping the operator learn the routine and common operation of the unit, operator training simulators enable staff to

• Recognise the onset of an upset.
• Experience the full severity of the upset in a simulated environment to reinforce its significance without harming production or the facilities.
• Be familiar with the tools provided with the automation system such as procedural operations and APC.
• Follow procedures to minimise the impact of the upset.
• Avoid similar upsets in the future.

Repeated practice on an operator training simulator helps the operator to recognize a stimulus and respond instinctively. Benefits include

• Faster startups accelerate initial profit recognition.
• Improved plant reliability protects profits and avoids penalties.
• Improved plant performance maximises profits without compromising plant reliability.
• Better product quality control avoids penalties without unnecessary give aways.
• Improved plant safety avoids costly injuries, damage, environmental penalties and material loss.

Operational Effectiveness
The ASM consortium has developed a set of guidelines and technologies that incorporate process domain knowledge and can be customized for the plant and process unit.

These tools help operators make sound decisions during real time operating scenarios by presenting:

• Operating graphics and boundaries that focus attention to critical data.
• Alarm strategies that adapt to changing operating modes.
• Procedural operations that guide the operator through complex sequences.
• Models for prediction of equipment performance.
• Safe operational boundaries and notification of excursions.
• Warnings based on relationships between real time operating data before they become alarms, trips, and incidents.
  These tools protect plant profitability and enhance the operator's ability to see important data and make well informed decisions during operation, thereby avoiding process upsets and maximising plant availability.

Operations Monitoring
Much experience is gained in the early operation of the unit. It is critical to have tools in place to set the correct expectations and capture knowledge gained.
A key area for defining and sustaining performance is to ensure that the plant is consistently operated within the correct limits. Equally important as a means of capturing knowledge and lessons learned is the ability to identify excursions beyond de ned limits and the reason for the excursion. Having these solutions in place during initial commissioning efforts provides an effective way to focus attention on safe operation and issues, which need to be addressed.
In addition, technologies, which assist in capturing and recording operating knowledge, are critical tools for continuous improvement efforts. Tools to capture shift level logs and operating conditions provide the ability to identify issues to be resolved and can help point to additional training and communications needs.

Production Optimisation
Several key technologies are routinely applied to refinery and petrochemicals plants to optimise performance and monitor the performance of the plant. These tools are commonly applied long after the plant is operational and these delays can cause a significant loss of value during the window of operation when optimisation is not applied.

Advanced Process Control
The use of multi variable predictive control (MPC) applications provides tremendous capabilities for controlling and optimising the performance of complex process units. These applications provide minute by minute monitoring and control using models of the interaction between key variables. These models are typically developed by performing online plant step tests that create small perturbations in process conditions and identifying the resulting dynamic relationships. A dynamic simulator can be used to reduce the plant step test time by enabling models to be identified  before the plant is put in operation, resulting in faster realisation of APC benefits. These models can be quickly updated against the live plant once start up and initial stabilisation is achieved. This also offers the benefit of enabling earlier training in the use and behaviour of the advanced control solution.
Simulation and optimization models can be used in a tiered control strategy that is built upon a strong foundation of many integrated advanced controllers throughout the plant. The financial payback of the advanced process control and optimisation strategy will typically be achieved very rapidly as a result of improved control and optimised production.
Remote Performance Management Even with the plant running smoothly, there is a need for ongoing vigilance. With tens of thousands of data points to monitor, though, process engineers can be flooded with data and starved of information. Remote performance monitoring and management technologies enable a highly secure, collaborative environment, configured and customised to a customer's specific workflow, and enable designated experts, wherever they might be, to review key operating parameters and make recommendations.

Expected Benefits
While each facility has its own opportunities, financial characteristics and challenges, it is easy to recall a tough startup or a harmful incident that one never wants to repeat. Reflecting on what went wrong helps put everything in perspective when considering the motivation for implementing procedures, tools, and training that improve operational readiness and effectiveness from day one.
Here are some of the key benefits that can be achieved by leveraging these key technologies:
 

• Improved capital cost management with fewer bottlenecks.
• Improved operator training and readiness.
• Improved automation systems and tools to provide clear, early identification of problems.
• Effective, automated procedures for startup and shutdown.
• Use of operations monitoring tools to capture knowledge of unit performance and support continuous improvement.
• Early application of advanced process control.
  For a 100000 bpd refinery that makes USD 5 margin per bbl, it only takes one day of schedule improvement to save USD 500000 during startup. Additional savings and increased revenues are possible due to the early application of APC tools and the ability to operate the unit at planned production rates much earlier than using the traditional approach.

Conclusion
With a renewed focus on making every dollar count, new approaches are required that take advantage of key research, technologies and best practices to improve the readiness and operational effectiveness of a new process unit. These improvements are achieved throughout the lifecycle of the unit from design through unit optimization and have a significant impact on the return on capital employed.

Patrick Kelly
is Vertical Marketing Manager with Honeywell
E-mail : patrick.kelly@honeywell.com