Simulation solutions target compressors, consumption and emissions

Paul Boughton

Plant simulation is a critical part of any plant management strategy today and process companies are turning to the most sophisticated solutions on the market. Sean Ottewell reports.

Using dynamic modelling and simulation, Aspen Technology’s version 8.6 of its aspenONE software addresses a number of significant issues for the process issues. 

Among a raft of new features included in v8.6 is Activated Dynamics Analysis, which allows dynamic modelling of compressors - a high value task requiring both expertise and experience. V8.6 of Aspen HYSYS software automates dynamic modelling with a single button click to speed up model setup and enable more process engineers to perform compressor operability screening. All companies operating compressors, especially those processing gas in upstream and midstream, will benefit from better flow assurance and reduced maintenance cost. AspenTech says that no similar capability is available in the market.

The new version also includes expanded pressure safety valve design and rating in Aspen Plus and Aspen HYSYS. In v8.6 new fire analysis scenario calculations - accounting for latent heat and temperature change - and rupture disk sizing have been added.  All functionality is available in both Aspen Plus and Aspen HYSYS, improving chemical and energy operators’ compliance with API 520 and 521.

Furthermore, new detailed unit rate estimating in Aspen Capital Cost Estimator (ACCE) extends the software’s scope further into the detailed estimating phase of a project.  ACCE v8.6 enables easy adjustment of labour and material unit rates as well as materials of construction. The result is expected to enable organisations to achieve up to 10% accuracy or better, reducing project risk and improving decision making around the use of capital.

Explaining the benefits of v8.6, AspenTech executive vice president of products Manolis Kotzabasakis said: “AspenTech continues the high pace of innovation with the release of aspenONE Engineering version 8.6 software.  Delivering on the Unified Engineering Environment first introduced with Version 8, breakthrough features such as Activated dynamics, pressure safety valve sizing, and addition of detailed costs to conceptual estimates are industry firsts that translate into day-to-day productivity improvements for our customers. More than ever, our customers require the capabilities of a unified engineering environment to be successful.”

Commenting on the new Activated Dynamics Analysis compressor surge feature, Ian D Wyatt, principal engineer with WS Atkins, said: “[This] is an innovative screening tool before full dynamic compressor modelling. It provides us with a good starting point to perform a compressor study across a range of scenarios. The data is presented in a well-organised manner, and pre-made results displays are convenient.”

“The new safety environment in Aspen Plus v8.6 will not only allow us to standardise our relief system documentation company-wide, but it will also provide us with the confidence that the calculation methodologies across the company are high-quality and accurate by using conditions already captured in our current process models,” added Shashank Shah, senior principal engineer with Arkema.

For Yokogawa, new solutions aimed at optimising process industry plant operations are a priority. These are provided as part of the company’s VigilantPlant Services suite that supports safe, stable and highly efficient plant operations. The technology underlying these solutions is Yokogawa’s newly developed Mirror Plant online simulator.

The simulator can visualise the internal state of a plant process and make near-term predictions on plant behaviour. Described by Yokogawa as an industry first, this simulator operates in synchronisation with the plant control system and features the level of performance required in commercial plants.

Based on real-time manufacturing process information and using a proprietary function for adjusting model parameters, Mirror Plant precisely simulates the state of a plant. Using plant models, it visualises the current state of the plant, the state of the plant up to several hours in the future, and the state at plant locations where it is not possible to measure temperature or pressure. It then displays these results on screen at a Centum VP integrated production control system operator terminal or at a standard PC. Mirror Plant also has an alarm function that can alert operators to potential problems. 

The simulation models used in Mirror Plant are built based not on statistical data from plant operations, but on physical laws. Thus, says Yokogawa, processes can be theoretically verified, and the simulator can be used for a broad range of applications such as identifying problems in a process. The optimum operating conditions can then be identified before making changes to items such as the production volume or the feed material composition. 

Mirror Plant was developed based on the OmegaLand integrated dynamic simulation environment and its core technology, the Visual Modeler plant simulator. Both software packages were developed by Yokogawa’s subsidiary, Omega Simulation.

Meanwhile Finnish company VTT has successfully completed a project with Japanese cement manufacturer Ube Industries to develop a simulation model that helps to identify the best operational practices needed to reduce both energy consumption and emissions. 

The work was based on VTT’s existing modelling tool KilnSimu. This models the chemical reactions and phase changes in a rotary kiln, as well as their thermal and energy balances. With Ube Industries, the simulation was coupled with other modelling tools and modified to meet the company’s process parameters and operational experience.

The customised KilnSimu tool predicted successfully cement clinker crystal formation and composition. It also estimated reliably the circulation of harmful sulphate and chlorine species both in the pre-calciner and in the rotary kiln. In addition, it showed how to control the secondary air and fuel inlets to minimise the kiln’s energy consumption. The model is now helping Ube Industries to optimise and control its process operations.

“For cement manufacturers, improvement of the process’s thermal efficiency is highly desirable. KilnSimu is a very powerful and useful tool for analysing the whole cement process. With it we can estimate the quantitative effect of process improvements,” noted a Ube spokesman.

Ube has three cement facilities in Japan with a combined production capacity of nine million tonnes/ year. Ube’s Process Technology Research Laboratory now uses KilnSimu to model the whole cement manufacturing process, from the pre-calciner subsystem to the rotary kiln and the clinker cooler unit.

Vessel designer saves €232,000/year with Autodesk software

Cameron Process Systems designs oil and water treatment vessels, which are complex as they can have more than 150 nozzle connections each. The speed up the design process the company recently made the move to digital prototyping with Autodesk Inventor. The new software has enabled the company to reuse designs and reduce errors. 

“With Inventor, we’ve built libraries of models that we can reuse quickly,” says Gary Foucault, Cameron’s design manager. “That’s a big help when you’re building vessels as complicated as ours. The 3D models have also helped us to reduce design errors and communicate our ideas more clearly to field installers and clients.”

Originally, the many nozzle variations meant that the modelling process lasted 3-4 weeks. Hoping to further expedite the design and drafting phase, Foucault closely examined the XML data being generated by the COMPASS calculation software and realised that all the data needed to generate models was already in the application. ”We just needed an intelligent, automated way to pull out the relevant data and use it to generate 3D models, drawings, schedules and part lists,” he added. 

With Autodesk Inventor Engineer-to-Order, Cameron can now automatically create drawings that offer multiple views of a vessel, nozzle schedules, and complete parts lists pulled from the company’s parts database. 

“With Autodesk Inventor Engineer-to-Order, our office is saving about US$60,000/year (€47,000) in avoiding errors in our nozzle schedules and parts lists. Multiply that by four other offices and we’re looking at savings of up to US$ 300,000/year (€232,000),” concluded Foucault.