Four years ago, the International Energy Agency (IEA) asked “are we entering the golden age of gas?” Today, the North American shale gas boom, expansion of LNG trade, and new LNG and natural gas fuel systems, technology advancements, and delivery and storage enhancements support a resounding “Yes!” answer to that question.
A natural financial incentive
Along with others, these developments have triggered a substantial international downward movement in cost, as well as stabilization in natural gas prices, spurring its use due to a significantly widening price gap between oil and natural gas.
In other parts of the world, particularly Asia and Europe, natural gas use has been growing as an important fuel for power generation and transportation. Technological developments in pipeline safety and gas compression have facilitated the widespread transport of gas on land. The advancement of liquefaction technology, allowing for the secure growth in LNG production at competitive prices, has been a significant contributor. This has made it possible to ship natural gas far and wide, in an economical and safe manner.
LNG growth factors
Figure 1. Fuel cost per hour with natural gas blending (courtesy of Parker Hannifin field integration partner).
Global natural gas demand is expected to grow by 20% from 2013 to 2019, according to Jérôme Ferrier, President of the International Gas Union (IGU). LNG growth factors include:
- The desirability of larger process train sizes, made possible by the development of larger cryogenic heat exchangers
- The emergence of new geographic locations, predominantly inland, for liquefaction plants. These plants are enabling small, unconventional drill sites and waste, bio and landfill-based gas production sites to purify and transport gas easily in remote locations with no pipeline infrastructure.
- An increase in new LNG customers with different LNG specifications
- An expanding range of LNG applications, from unconventional drilling and transport to floating production, storage, and offloading (FPSO) vessels
Another significant growth factor is the development of a comprehensive, mobile-ready LNG transport and delivery system. Here, lighter weight tank technologies are inspiring more confidence from OEMs and end users in both stationary and mobile applications. This is because the new tank systems offer greater thermal efficiency, durable submerged cryogenic pumps, and efficient vaporization and regulation systems, that guarantee a steady flow of gas.
Pure natural gas or blended dual-fuel?
The availability of a wide range of natural gas engines with advanced fuel control systems for natural gas, as well as reliable and clean dual-fuel enabled engines, are key to selecting the best fuel option for a specific application.
In the U.S. and other industrialized nations, older diesel engines are increasingly restricted to emergency standby or limited duty service due to air emission concerns. The newer Tier 4 compliant engines come with complex and expensive emissions control technologies. Consequently, the natural gas-fueled spark-ignition (SI) engine is now the engine of choice for the higher duty cycle stationary power market. This is not true for applications such as drilling and pumping, or mobile applications such as construction, mining, rail, or marine. However, recent fuel system breakthroughs, as well as emission concerns, are increasingly motivating some users in certain segments to make the switch to natural gas SI engines for new purchases. In these cases, a pure natural gas based control system is the preferred option.
When selecting a pure natural gas engine, users must choose between rich burn and lean burn engines.
- Rich-burn engines have a thermal efficiency of approximately 36%. They easily achieve compliance with emission regulations using an oxidation catalyst and provide diesel-like performance. However, they have lower fuel efficiency.
- Lean burn engines can achieve a thermal efficiency as high as 42%, leading to significant savings. Additionally, the engine emissions are low and offer easy compliance. NOx emissions are the critical driver for a lean burn.
For the existing large installed base of diesel engines in the world, there are considerable price and environmental advantages to adopting dual-fuel engine technology. Dual-fuel systems blend two fuels together for use. This is different from bi-fuel, where an engine can run on two fuels, but only one at a time: for instance, 100% natural gas or 100% diesel. Because the cost to convert the entire engine to run efficiently on 100% natural gas is very high, dual-fuels provide a cost-effective compromise, allowing users to enjoy the lower operating cost benefits of natural gas fueling without extraordinary investment.
To learn more about Parker's solutions with the alternative fuel products such as LNG and CNG fuels, visit our website.
Article contributed by Veriflo Division of Parker Hannifin