EICS Offers Ultralow Emission Option

Published on Sep 03, 2013

This article was previously published in the August 2013 issue of The American Oil & Gas Reporter. It is reproduced here with permission.

By Darrell Schmitt and Thomas Martino

As producing and midstream companies work to reduce emissions in compliance with federal and state regulatory requirements, the challenge becomes maintaining continuous compliance while maximizing the operational and economic performance of equipment and assets.

For engines operating in gas compression and production applications, as with those in other oil and gas applications, electronic engine control systems are the key enabling technology for achieving the dual (and sometimes competing) goals of optimizing performance while lowering emissions.

State-of-the-art engine integrated control systems (EICS®) are engineered to continuously maintain engine performance at optimum levels while achieving ultralow emissions, even with changing operating and fuel quality conditions.

By integrating all key engine operational controls in a single user-friendly system, the technology is designed to generate and maintain operational efficiency throughout the life of the engine and its systems, allowing operators to meet emission regulations while optimizing output and saving time and resources. The engine control modules (ECMs) of the newest EICS technology integrate components that manage: Ignition and timing, Air-to-fuel ratio, Speed governing, Diagnostics, Efficiency, and Regulation and reporting with local/remote user interfacing.

The technology can be packaged for performance to include the ECM; an air/fuel-management, electronic fuel control regulator (D-EPR); an air/fuel management mixer; electronic governing, suction/discharge pressure-based speed control; capacitive discharge ignition; and a color graphic display for operator interface and diagnostics. For emissions control, an integrated catalyst/sensor package can be added to the EICS performance package at any time.

By combining these key components into a single system, EICS technology is designed to save costs and labor associated with installing and calibrating separate products. The system is preconfigured, precalibrated, and dyno-tested for a specific engine model, which is done using various combinations of engine load, speed and fuel quality. When these targets are manipulated and held constant, target tables can be developed that include multiple air/fuel set points and ignition-spark tables.

Normally, when the instruments are supplied separately and then configured to work together, more often than not, they tend to “fight” one another. But integrating all the components within a single “smart” controller ensures that all functions and instrumentation work in harmony and in accordance with the operating and emissions performance requirements. Some original engine equipment manufacturers have come to this conclusion after trying to create functional systems with separate component parts. More so than any other major part, the engine must operate correctly or the operating performance will suffer, and/or the emissions coming out of the engine exhaust stack will increase, thereby adversely impacting economics. Incorporating all the functionalities of the component pieces into one integrated system not only improves efficiency and performance of the engine, but also allows advanced diagnostics capabilities on the entire control system.

The integrated packages come complete with all necessary mounting hardware and harnessing, and require minimal onsite setup, so that the operator can install the system and be ready for startup on the same day. Unless there is a diagnostic problem, the operator does not need to be on the site while the EICS runs, and he can monitor its progress and operations remotely thru an RS-485 communications connection.

The EICS uses a color graphic display as an operator interface that includes diagnostic fault codes and messages that immediately tell the user if and what the problem is, and guides him toward a corrective solution quickly, which ultimately saves both time and money.

Complying With RegulationsAlthough fairly new to upstream oil and gas compression and production operations, EICS technology has been applied in other industries for years in engine systems for fork lifts, power generation and off-road equipment. The latest EICS systems are purpose-engineered for the atural gas compression industry, but have been developed utilizing the same proven technology base.In nonattainment areas such in Harris County, Tx. (encompassing the Houston metropolitan area), new compression equipment entering service must meet a lower emissions standard of 0.5 grams of nitrogen oxide and 2.0 grams of carbon dioxide per brake horsepower an hour (bhp/hr), in most cases.

The EICS emissions package has been designed to meet these standards so that it can be used to maintain ultralow emission rates for a sustained period in nonattainment areas. However, even the most reliable piece of equipment eventually will require maintenance or repairs, just as any other engine system does. But if, for instance, an operator needs to replace an oxygen sensor, he will not have to retest to see if the engine is meeting emissions, because the system already is precalibrated to achieve those preset targets.

The EICS performance package was designed with fuel efficiency in mind while not sacrificing engine power. In field testing, a standard compressor engine equipped with EICS technology and the EICS emissions package is designed to operate in areas that need to meet 0.5 gr/Bhp an hour NOx and 2 gr/Bhp an hour CO2.

Even though some production companies will not need to meet nonattainmentarea emission standards, the technology was designed to optimize the performance of an engine to have better uptime by reducing downtime and lost production because of diagnostic issues.EICS offers automatic speed control, based on either suction pressure or discharge pressure. A target set point is developed to enable the engine to efficiently operate at varying rpm (from a minimum to a maximum target) to maintain a given pressure. That equates into extended runtime, eliminates excessive downtime, and translates to extended engine life. Because of the reduced downtime, there are fewer trips to the site.

When an EICS-equipped compressor engine is used on wells with fluctuating pressures, the system will adjust the engine speed automatically to compensate for those fluctuations, and will maintain the pressure within the limits set. If the EICS operates within those set points, the system will continue to run and production will go smoothly. The system offers an automatic speed control mode, which reduces shutdowns.

Optional Emissions PackageFor maximum emissions control, the EICS emissions package can be added to include the catalyst/sensor kit (including a post-catalyst oxygen sensor that includes a temperature monitor) to operate at optimum performance of the catalyst’s “sweet spot.” This metal substrate device has a specific wash coat of precious platinum based metals–the “secret sauce”–that absorbs and releases oxygen in the catalyst area. When the exhaust coming from the engine flows across this material at a specific temperature, it causes a chemical reaction that splits off oxygen molecules, so that what comes out of the exhaust is as close to clean air as possible.

The EICS catalyst is loaded heavily with precious metals and a wash coat specifically designed to be used with the system to optimize emissions performance. The EICS controls the fuel and air mixture to the engine through a dithering strategy of the fuel. It richens and then leans the fuel mixture through the fuel control system so that the catalyst can absorb and release oxygen as designed.

The EICS also has the capability to work with bifuel applications using field gas as the primary fuel. For instance, the engine can be started with propane, then once the field is operating and begins flowing natural gas, the EICS can switch to controlling the fuel coming out of the well.

The operator does not have to program this option beforehand in most cases, and once the natural gas fuel pressure reaches a certain critical point, the system automatically switches over. The EICS has to recognize a change in fuel quality through a switching device, which automatically adjusts maps to maintain engine operations.

Artificial LiftEICS technology is being used not only with compressors in gas fields, but also in artificial lift applications in oil fields. Houston’s Diverse Energy Systems is using the bifuel application on EICS packages it operates in conjunction with its FlowFast™ jet pumps in unconventional wells in North Dakota’s Bakken/Three Forks horizontal play, as well as in conventional vertical wells in Texas.

The company had a few issues with the application initially because of improper installation, but the system has worked well otherwise. Diverse Energy Systems estimates that the bifuel application saves its customers $10,000-$16,000 a month on diesel and electricity costs (as much $192,000 in annual savings).

The company primarily uses Caterpillar 3306™ and 3406™ engines. The EICS system allows the engines to burn high Btu associated gas–up to 2,250 Btu–with little to no conditioning of the gas, giving operators a viable and versatile new option to flaring that can provide considerable cost savings in locations that have no electricity or cannot use diesel fuel or flare associated gas.

Produced gas sourced directly from the well is not stable and Btu levels can fluctuate significantly, causing erratic engine performance and increased maintenance and repair costs. Diverse Energy Systems is overcoming this challenge by equipping its field gas-fired engines with an EICS.

By combining numerous engine control and optimization capabilities into a complete integration package precalibrated for the specific engine model, the EICS enables the engines to accommodate wide variations in fuel composition and speed/load ranges without the need for manual field adjustments. It maintains efficiency even in the toughest jet pump and gas lift applications, while ensuring emission compliance, which is further enhanced by reducing the volumes of flared gas in a lease site.The system’s built-in communication capabilities, air/fuel ratio control, and diagnostics functions all provide key benefits for Diverse Energy Systems’ customers.

An EICS can be installed by one person in only a few hours. Once in place, it requires little maintenance and can be monitored remotely, freeing operators to focus more of their time on core value-adding activities.

With emissions regulations expected to continue to tighten and production costs increasing, integrated engine control is becoming ever-more critical to the economic operation of compression and production equipment. The technology has been developed to increase engine efficiency without losing power, reducing and monitoring emissions, decreasing downtime during production, and reducing costs and downtime.

The technology will continue to evolve to provide effective and autonomous control of engine performance in even the most demanding applications, including meeting emission regulations in nonattainment areas.

Darrell Schmitt is the EICS product sales manager at FW Murphy, responsible for the air-fuel ratio, EICS and ignition product lines. Schmitt has worked with operators and users around the globe since 1978 to assist in applying monitoring, protection and control technology to improve the operational efficiency and emissions compliance on spark-ignited, reciprocating, internal combustion engines. Schmitt now is focused primarily on applying state-of-the-art industrial ignition systems, air/fuel ratio, and integrated control systems for spark-ignited gaseous fueled engines.

Thomas Martino is the FlowFast™ jet pump product manager at Diverse Energy Systems. This role provides him the opportunity to deal directly with clients to bringing them reductions in lease operating expenses, increased production, and in general, solving problems both on the surface and down hole. Martino started his career in 1989 in natural gas compressor packaging. His 24 years in the oil and gas industry have been spent learning, operating and maintaining reciprocating oil field equipment.