Anthony Brough, P.E. provides business development support for CRDX. He can be reached at abrough@CRDXS.com.

Anthony Brough

For many of us in the large rotating equipment market, gas turbines are our main area of focus, and for good reason. Gas turbines are manufactured using leading-edge metallurgy, coatings, and aero-centric geometries to efficiently deliver rotational power at very high temperatures and pressures. But many times, the receiving end of this rotational power is equally impressive compressors, deployed for a variety of critical industrial processes.

The centrifugal compressors market is served by over 20 OEMs globally, producing over 2,000 units per year. In 2022, the value of this market (not including related aftermarket repairs) was approximately US$3.4 billion.

This market overview focuses on units rated above 1 MW and does not address positive displacement, diaphragm, or axial compressors.

There are two types of centrifugal gas compressors: in-line (also called beam-type or between-bearings type) and integrally geared. In-line compressors have one or more impellers in a single casing, generally with the impellers located between two radial bearings on a single shaft. An exception to this rule is the single-stage gas pipeline compressor with an overhung impeller (both radial bearings on the same side of the impeller) and axial inlet. All impellers within an in-line compressor casing rotate at the same speed.

In contrast, integrally geared compressors have two or more impellers, each located in its own casing with each casing mounted on a single gearbox with a single bull gear driving each impeller through a pinion gear. This arrangement allows each impeller to rotate at a different speed. The required total pressure ratio is achieved by having the gas move through two or more single-stage compressors in series. 

Incorporates a single impeller on an overhung shaft with the gas inlet oriented directly into the impeller eye, with the gas discharging radially. Due to reduced gas turning this design is more efficient than beam-style compressors and can achieve efficiencies above 90%.

Incorporates one or more impellers mounted on a single shaft between two bearings. The casing split is vertical, which allows for better sealing at higher pressures, up to 1,000 bar.

A type of radially split-barrel compressor with one to four impellers mounted between two bearings. Generally used for multistage pipeline boosting applications.

A design featuring a high-speed variable frequency motor driving one or more compressor impellers in a hermetically sealed casing that uses magnetic bearings. Benefits include reduced weight and footprint compared to traditional designs and no possibility of oil or gas leaking into the environment.

TYPICAL APPLICATIONS FOR CENTRIFUGAL COMPRESSORS

Applications served by centrifugal compressors (as segmented in this report) fall into three oil and gas sectors and one industrial sector:

These compressor applications are seen in oil and gas production operations, both onshore and offshore. They include initial processing operations done close to the point of extraction, including the dehydration and separation of liquids. Also included in upstream activity are compressors used in LNG liquefaction plants. (Note, some view LNG liquefaction as a downstream activity, but for the sake of this article, we are including them in the upstream segment.)

There are thousands of compressors used in gas transportation via pipeline as well as compressors used in underground gas storage applications. This segment also includes fuel gas compressors for gas-fueled power plants.

Compressors may also be used in refining and petrochemical production processes. These applications also include compression needs for fertilizer production and its precursors (ammonia, urea, nitric acid, etc.).

Compressors used in other industrial applications, including air separation, CO

, compressed air energy storage, and plant/process air compressors over 10,000 m

The more than 20 OEMs that serve the centrifugal compressor market manufacture multiple configurations of these compressors including: 

While many of the OEMs in this market primarily serve a regional customer base, for example, those in Russia, China, and India, other OEMs serve the market on a global basis. Many of the globally diverse OEMs have broad product lines, like those mentioned above, while others have a narrower focus on specific product types.

A detailed review of these OEMs, the market segments they serve, and the product types they offer are included in Dora Partners & Company's annual 

. The largest OEMs serving this market include Baker Hughes, Siemens, Elliott Group, MAN Energy Solutions, Solar Turbines, Mitsubishi, Atlas Copco, and Shenyang Blower Works.

A detailed analysis of the market suggests that the annual OEM revenue for centrifugal compressors is more than US$3.4 billion per year. In 2022, approximately 2,300 units were ordered from the OEMs included in our study.

From a unit quantity perspective, the industrial segment is the largest, but most of these units are smaller and less expensive than the compressors used in the other segments. Units used in upstream applications are generally the most expensive, followed by those used in the midstream and downstream segments. From a total revenue perspective, downstream is the largest application segment.

There are significant differences in driver types across the application segments, with gas turbines frequently being used in the midstream and upstream segments, and steam turbines often being used in the downstream segment. Electric motors are used in all segments with almost all units in the industrial segment using this driver type.

From a geographic perspective, the largest destination region is Asia-Pacific, followed by the Americas. 

Unlike many pieces of rotating machinery, such as gas turbines, reciprocating engines, and reciprocating compressors, centrifugal compressors have very few, if any, parts that are life- or wear-limited and require replacement on a scheduled basis. A well-designed and maintained centrifugal compressor can run for decades with very little corrective maintenance. As a result, most aftermarket revenue associated with centrifugal compressors comes from both parts and services that are required when something fails or revamps the equipment to modernize it or change its capabilities.

Dora Partners has estimated that 2023 will result in new unit orders of more than US$3.6 billion, with a relatively consistent growth forecast over the next 10 years. Overall, the market is expected to grow most rapidly in the Asia-Pacific region and the industrial market segment.

Upcoming market trends include growth in LNG production, carbon capture and storage, subsea compression, and hydrogen/ammonia applications, as worldwide decarbonization initiatives advance across the globe.

Note: Dora Partners & Company’s detailed report provides a much deeper evaluation of each market segment, product strengths for each of the main OEMs, and a 10-year forecast segmented by upstream, midstream, downstream, and industrial sectors. The report includes regional and OEM market share information, application, and trend observations. In addition, OEM profiles are provided detailing product and market strengths for the top nine compressor OEMs.

About the Authors: Anthony Brough is the Principal Consultant at Dora Partners & Company, and Tony Ruegger is the Senior Consultant at Dora Partners & Company.

Articles

A high-level overview of the centrifugal compressors market.

Centrifugal Compressors: The 'Business End' of Many Critical Industries

Hydrogen is the most abundant element in the universe. As a carbon-free energy source, it represents one of the paths to a decarbonized energy supply. Flipping the switch to a decarbonized, green tomorrow would be wonderful. The reality is that a number of considerations, technical advancements, socio-economic hurdles, and resource limitations need to be navigated first. This article explores the current state of hydrogen as a fuel supply; what can be accomplished within today’s installed base of power generation; identifies intermediate hydrogen-based carbon reduction solutions; and outlines the advancements necessary to realize the vision of an entirely hydrogen-fueled gas turbine power generation fleet.

When looking for carbon-free energy sources, the most apparent options are solar, wind, hydro, and nuclear. Yet each of these present unique constraints when asked to satisfy the world’s growing demand for electricity. With their fuel flexibility and high efficiencies, gas turbines have increasingly been relied upon to meet the growing global demand for power. Hydrogen represents a means to leverage this installed base to supply car-bon-free electricity in a less disruptive manner than a complete transformation to new power generating technologies. Fueling gas turbines with pure hydrogen produces only water vapor with zero CO

Hydrogen has been successfully blended with the fuel supply in gas turbines for decades. Recent field demonstration tests have shown successful operation at up to a 44% blend of H

 by volume for aeroderivative gas turbines, and up to 20% for large heavy-frame gas turbines. One concern with combusting hydrogen is increased NO

 emissions due to increased flame temperature. Studies have demonstrated negligible change to NO

Table 1: Hydrogen vs. natural gas properties

Gas turbine OEMs are projecting the capability to operate on 100% hydrogen without impacting NO

 formation, primarily through advancements in combustor design and minor if any changes to existing SCR reliance.

The key to unlocking the full potential of hydrogen as a carbon-free energy source is to convert unused solar, wind, hydro, and nuclear energy available during low-demand periods to hydrogen via water electrolysis. The stored hydrogen produced can then be utilized as an alternate fuel by gas turbines to generate carbon-free electricity during high-demand periods.

Today, the United States utilizes approximately 10 quadrillion BTU/yr of natural gas to produce electricity, according to the U.S. Energy Information Administration. Total hydrogen production is approximately 1 quadrillion BTU/yr. Of this, green hydrogen production capability is only 269 trillion BTU/yr. Note that the vast majority of hydrogen produced today is NOT used to generate electricity—nearly all in the United States is used in refining petroleum, treating metals, producing fertilizer, and processing foods. Petroleum refineries use it to lower the sulfur content of fuels. With the introduction of the Inflation Reduction Act (IRA), the hydrogen industry is poised to take the biggest steps seen to date toward closing this production gap, with a $3/kg tax credit available for green hydrogen production and lesser amounts for more carbon-intensive forms of hydrogen production.

Figure 1: The hydrogen color wheel. Courtesy of MHI.

As the availability of hydrogen continues to grow, opportunities will arise for power utilities to introduce it as a carbon-free fuel stream for their gas turbine fleets. Making the change from natural gas to 100% hydrogen in a single step may not be feasible in the near term given the required energy consumption and lack of availability of hydrogen. A reasonable approach may be to introduce it in increasing volume in blends aligned to availability in given geographic areas. The following factors should be considered when approaching these blending opportunities: hydro-gen supply and storage, fuel conditioning and blending skid design, gas turbine capability and period of use, and personnel safety and training.

Table 2 provides a mathematical model of a blending application for a 60Hz GE LMS100 PA+ gas turbine genset operating in simple cycle mode. Figures presented are based on published full-load, beginning-of-life performance for the LMS100 PA+, based on data from GE Gas Power. Based on the relative density and LHV differences between natural gas and hydrogen, one can see the total flow more than triples as you approach 100% hydrogen operation. (This model assumes the line pressure does not change across the range of blending %.) An important consideration for retrofit applications is accommodating this increase in volumetric flow once the 75% blending threshold is approached, where total flow is approximately doubled. Existing piping infrastructure supplying the genset, as well as the fuel delivery piping at the combustors, will need to be evaluated for the increased relative pipe velocities this will result in.

Table 2: Model of a hydrogen-blending application. Courtesy of CRDX.

Assuming the hydrogen delivered in the Table 2 example is green or pink hydrogen, another interesting point is the amount of water required. These figures represent the theoretic water necessary to produce hydrogen, which are significant in and of themselves, but do not take into consideration any losses encountered during the purification process of the water to meet a given electrolyzer application. For instance, if sea water is considered as the water source, a desalination process is necessary as well as a deionizing process. Considerations and technical advancements in this area will be necessary to introduce green or pink hydrogen at the scale necessary for power industry consumption.

Blue hydrogen, and turquoise hydrogen (further down the road) represent alternate sources of carbon-free hydrogen that are based on the conversion of natural gas with some form of carbon sequestration. For blue hydrogen, carbon capture and sequestration systems are added to the existing grey hydrogen reforming process to eliminate CO

 emissions. For turquoise hydrogen, a pyrolization process produces hydrogen and carbon in the form of carbon black versus CO

. The carbon is immediately sequestered and available for alternate usage points, replacing more carbon intensive sources.

Hydrogen represents a promising way to reduce the carbon footprint of the power industry. Growing advancements in hydrogen production technologies coupled with strong support from the federal government by way of the IRA bring the opportunity to deliver solutions to the forefront. State and local incentives likewise serve as a catalyst for adoption.

Figure 3: H-Cubed hydrogen blending by CRDX

Recent in-the-field hydrogen-blending demonstration projects on both aeroderivative and heavy-frame gas turbines indicate the power sector is ready to take the next step. Implementing a gradually increasing hydrogen-blending strategy for the gas turbine fleet represents an opportunity to realize these benefits today while laying the framework to support a carbon-free energy sector of the future. 

Gus Graham is Business Development Manager at Carbon Reduction Systems (CRDX), a technology-based manufacturing company developing products and services for reducing the use of carbon-based fuels and their emissions. Visit www.crdxs.com or call +1 518-765-8329.

Hydrogen plays a significant role in decarbonizing power generation.