Key ethylene trends

O&G. What are they key trends that you are seeing in the ethylene industry?

Giorgio Greco. The ethylene industry is undergoing a significant structural shift. Back in the 1990s, North America and Europe were home to over 70 percent of the world’s capacity in addition to being the biggest markets in terms of polyolefin demand. Since then trade flow patterns have evolved dramatically, indicating a fundamental shift in market dynamics – the Middle East is now emerging as the dominant net exporter of ethylene derivatives, while Europe and even North America are shifting to net importer roles. And Asia, although it is now making massive investments in ethylene assets, continues to be a growing net importer.

O&G. When exactly did the Middle East region enter the petrochemical sector?
GG. The Middle East’s strategy of building the petrochemical sector by leveraging its cost advantages began in the late 1970s, with Saudi Arabia’s strategic decision to add value to the associated gas that was previously being flared. The real cornerstone for this approach was the commissioning of SABIC’s joint venture capacities at Yanbu and Al Jubail in Saudi Arabia in 1985.

O&G.What would you say are the key distinguishing factors of ethylene plants compared to other units in the petrochemical industry?
GG.Ethylene plants are extremely capital and energy intensive. Temperatures vary along an ethylene plant from as high as 900°C down to cryogenic range (well below -100°C) while on the process side pressures range from atmospheric up to 40 bar, and can reach up to 120 bar for the steam system. All these factors contribute to making ethylene plants among the most complex in the petrochemical industry. In addition, because ethylene is a cost driven market, the full exploitation of economies of scale is exponentially escalating the size of compressors: 3D impellers with diameters of 1.7 m or more and megawatt steam turbines for mechanical drive well above 50 MW are becoming the norm in the industry.

O&G. What implications if any does all of this have for the technology being employed within the industry?

GG. The changes in market fundamentals are profoundly affecting technology. Large export oriented complexes enjoy major economies of scale, and are leading to increases in the viable commercial size of ethylene crackers. The one million ton per year plant size introduced into the industry less than five years ago is already the industry benchmark.

The technology implications are huge. Taking the Middle East as an example, since production in the region will be primarily for large export markets equipment has to be much larger and more efficient than ever before. In addition, in order to maximize production end users are demanding availability of up to five years or more for rotating equipment. This translates into a completely new approach for machinery design, including the extensive use of computational fluid dynamics, the optimization of aerodynamics for injection and discharge, new manufacturing technologies such as full milling single-piece impellers, and full testing capabilities for these large machines, from rotor to the complete train.

O&G. How are equipment suppliers like GE Oil & Gas handling capacity and performance challenges?

GG. At the core of a plant’s performance are steam turbines and compressors – machines for which GE has posted remarkable achievements in recent years. Our engineering teams work closely with customers and process licensors to constantly push the conventional limits of unit size and performance. Recent technology advances have extended ethylene plant capacity beyond 1.2 MTPY, with impeller dimensions of 1.8 m and mechanical drive steam turbines well above the 60 MW mark.

Compressor efficiency has increased two to six percent over the past five years through improvements in flow path design and manufacturing processes – including 3D impeller design and single-piece forged steel impellers. On the steam turbine side our R&D program is focused on getting ready for mechanical drive applications that go beyond 100 MW, as well as optimizing inlet systems to enhance efficiency.

Giorgio Greco is Downstream Marketing Manager for GE’s Oil & Gas business. Prior to joining GE in 2006, Giorgio worked within Snamprogetti’s Strategic Planning Office, later moving to Saipem after the merging of the two Engineering and Construction companies of the Eni Group.