Jennifer Dyment reports on optimising plant performance with robust column analysis
Sophisticated analysis leads to vital discoveries and opens up a world of opportunities. Being able to deliver intelligent insights into plant behaviour and tackle complex operational issues with the use of advanced technology can add significant value to the entire production lifecycle.
Leading chemical and energy companies today are using innovative techniques to reduce energy costs, maximise asset effectiveness and equip engineers to make better operational decisions.
Distillation columns are notoriously difficult to operate and product quality and overall equipment effectiveness can vary based upon multiple factors, such as the age of equipment, feed conditions and even weather conditions.
Distillation is one of the most common capital and energy intensive separation processes. The capital cost is largely dependent on the column’s height to diameter ratio and structural material as well as the type of separation internals chosen.
Up to 40% of the total energy consumption can be incurred by a typical chemical plant in the distillation units alone, so optimising plant performance with robust column analysis can make a dramatic difference to bottom-line profitability.
According to a recent paper on Optimizing Multicomponent Distillation Configurations published by the US Department of Energy, “there are tens of thousands of suboptimal distillation columns in operation in the U.S. consuming approximately 2-3 Quads [quadrillion BTUs] of energy per year. In addition, the equipment dedicated to separations contributes 40 – 70% of the capital and operating costs in a typical processing plant”.
Whether you are planning to change the feedstock, increase capacity or just troubleshoot an existing problem, the first step in the process is to understand the operations more effectively. Advances in AspenTech’s simulation tools enable engineers to gain better insights into column behaviour based on current operating conditions and allows them to see the column as part of the wider production process.
The use of intuitive, interactive and visual graphics for tray and packing analysis and the resulting hydraulic plots for every stage gives greater detail on the hydraulic behaviour of the individual stages while simultaneously providing a view of the performance of the whole column.
The aspenONE Engineering suite contains software simulation tools that can now be used to rigorously model distillation column operations and help engineers to optimise separation processes and dramatically improve overall column performance.
Users of the software can easily calculate operating parameters and behaviour based on inputs of column size, feed conditions, packing and/or tray configuration and physical properties, including the heat and material balances, thermodynamic and equilibrium limits and much more.
Improved analysis capabilities can now enable engineers to gain deeper insights into key processes and allow them to problem solve and make better, faster decisions. With the new Column Analysis technology in Aspen HYSYS and Aspen Plus, engineers can readily analyse hydraulic performance and test operating parameters, resulting in up to 20% improvements in energy savings and millions of potential dollars in improved product quality and throughput.
With Aspen HYSYS and Aspen Plus, engineers can see precisely what is happening within the column. The column analysis functionality is an easy-to-use interactive visualisation tool that has been tested for ease of workflow to save time and effort. The tool includes enhanced validated calculations for improved accuracy of the hydraulic results of trayed and packed columns.
For example, if a chemical company is trying to push production capacity of a de-ethaniser unit in an ethylene plant, a column that was previously performance within hydraulic constraints may start to experience loss of separation efficiency.
By simply using the internals information supplied by the column vendors in combination with process data, it is easy to identify the operational issue which could be tray flooding. The flooding can be handled by changing the feed conditions like temperature or adjusting reflux or condenser pressure.
The effects of changing the column operation on downstream operations can be evaluated with an interactive solver. Once you understand the operating range, you can explore ways of improving the process operations and quickly communicate your findings with the hydraulic plots or a PDF report.
Column analysis in Aspen HYSYS and Aspen Plus intelligently provides warnings to help engineers identify the root cause of the operational issue while minimising the need for expensive physical inspection. Engineers can understand the operating range to improve the column operations and communicate their findings with peers with visualisations that clearly articulate the problems and the risks involved.
Optimising plant performance
By being able to see exactly what is going on inside the distillation column and rigorously model the unit, engineers and operators can quickly troubleshoot column issues, optimise operations and minimise capital used in revamps.
AspenTech’s cutting edge software modelling tools for column analysis offer an interactive capability with enhanced calculations and visualisations for the hydraulic behaviour of trayed and packed columns.
Today, it is possible to look at the column as part of the larger process with an interactive solver for quick evaluations of multiple operating cases. Operators can now gain a thorough understanding of the behaviour of columns to address or avoid operational mishaps with hydraulic plots, as well as understand the impact on downstream operations.
Advanced column analysis capabilities can reduce the use of energy and emissions and optimise overall operating expenses. The tools within the aspenONE Engineering suite are ideal for achieving robust column analysis, which create intelligent insights that drive superior performance for your asset.
Jennifer Dyment, Product Marketing, AspenTech.