Polyethylene has a huge number of uses. This important plastic is found in everything from food packaging and household goods to car fittings and water pipes. The current annual worldwide demand for polyethylene (PE) is 92 million tonnes, with this figure set to climb to 113 million tonnes by 2021 according to experts from IHS Markit1. To be able to meet rising demand for this plastic going forward, the petrochemical industry needs plants that are engineered for high throughput and reliable performance with flexibility to cover the full range of product options. In other words, PE feedstock – natural gas and crude oil – have to be converted to PE as efficiently as possible in a number of processing steps.Polyethylene plant in Litvinov, Czech Republic
New concepts for multi-unit plants
“The main elements of a petrochemical complex are the steam cracker and the PE plant. The purpose of the steam cracker is to convert longer-chain hydrocarbons into short-chain building blocks like ethylene, while the PE unit assembles the building blocks into polyethylene suitable for many purposes, both routine and advanced,” explains Dr. Franz Dalitz, Product Manager at Linde Engineering Dresden. “Engineering these petrochemical plants is an extremely complex undertaking. And even more so in recent years as production plants have got bigger and bigger,” comments Sebastian Holz, Vice President of Sales and Products at Linde Engineering Dresden. “This intensifies the need to develop new concepts aimed at simplifying processes while also offering added value to companies.” Reducing complexity is essential from the very first step. In the past, customers typically had all plant units designed and built separately before assembling them as a complex. “A customer would choose a particular technology from a licensor and then engage a contractor to engineer the plant at a later date,” explains Dalitz. “If you look at the overall project flow, however, it makes more sense to involve a contractor at a much earlier stage,” according to the Linde expert. Especially if that contractor has a wealth of expertise across multiple technologies like Linde. This is part of what differentiates Linde from its competitors.
Building process know-how into the project at an early stage
The purpose of the new cooperation agreement between Linde Engineering and Univation Technologies is to add value to the customer by reducing project complexity, increasing efficiency, and reducing costs. Univation Technologies licenses the world’s leading polyethylene technology, the UNIPOL™ PE Process. The volume of polyethylene licensed around the globe using this process stands at approximately 49 million tonnes per annum. This corresponds to over one third of global demand for two commercially important types of PE: high-density polyethylene (HDPE) and linear low-density polyethylene (LLDPE). “The alliance means that we can build our vast and long-standing engineering and process expertise into a project at a very early stage. By generating design documents via coordinated systems, the customer can put a more accurate estimate on their plant costs at earlier stages”, says Semra Gercek, Technology Delivery Director at Univation. The engineering software and data processing tools of both companies are aligned to also reduce the likelihood of workflow or timeline errors and increase efficiency overall. “Since the timeline is always one of the key success factors for any project, this alignment is a real bonus for customers,” adds Dalitz.Ethylene Plant Tasnee, Al Jubail, Saudi Arabia
Integrating plant components for greater efficiency
The Univation-Linde Alliance also focuses on integration opportunities for PE plants and steam crackers. The companies offer both Linde’s steam cracker and Univation’s UNIPOL™ PE Process as an all-in-one, end-to-end package. The benefits include optimised use of resources and integration of process systems across the two plants. For example, enhanced efficiency systems reduce unit operations in the plant. This increases overall process efficiency and conserves fossil fuels. Exhaust emissions are also reduced as less gas needs to be flared off and less auxiliary fuel gas is needed. “As the leading polyethylene technology licensor around the world, we are constantly looking for ways to deliver more value for our licensors,” says Dr Steven F. Stanley, President of Univation. “This agreement with Linde allows us to take our solution-driven approach to the next level, covering the entire UNIPOL™ PE Process platform including back-integration into steam cracker operations and improved economics for both new plants and retrofit plants.”
Dovetailing in-depth process knowledge
Linde and Univation are tried-and-true partners. The two companies have been teaming up on various large-scale plant projects for almost forty years. “We are very familiar with the plant design of the UNIPOL™ PE Process, but we needed much deeper and more detailed insights into the technology to integrate it with our steam cracker. A contractor would not normally have access to that kind of information. Similarly, here at Linde, we don’t usually share details on our proprietary technologies either. But this cooperation agreement now allows us to work closely enough to dovetail our respective process steps,” explains Holz.
Revamps made easy
Customers considering plant revamps also stand to benefit from the Univation-Linde Alliance. A revamp might be necessary if a customer wishes to increase capacity, change the PE product or modernise, for example, to comply with new environmental regulations. With these kinds of projects, engineering experience and process know-how play an even greater role than in the case of new-builds. “With revamps, we need to examine each plant component and decide whether it can stay as is or must be modified or replaced. Step by step, we work out what components are limiting plant capacity, how a new catalyst will affect the overall process and which processes can be fine-tuned to make them more efficient,” explains Dalitz. This is where Univation and Linde’s bundled know-how – tailored to each individual project – contributes to planning and execution efficiency. And the technology benefits of PE unit/steam cracker integration are particularly evident in the case of revamps.
The sales teams of Univation and Linde are currently visiting conferences and customers around the world to explain the various facets of the cooperation and the new opportunities it opens up for customers.