NETL Research Adds To Knowledge of Hydrates

	Yi Zhang, a research associate in the Geosciences Division at the National Energy Technology Laboratory’s Office of Research and Development performs her doctoral research at NETL. She is preparing an experiment in one of the high-pressure reactors associated with NETL’s Hydrate Facility. She is studying the thermodynamics of hydrate formation by performing experiments on hydrate formation and dissociation from gases dissolved in aqueous systems and by improving theoretical models to predict and describe this phenomenon. This work will impact both the carbon sequestration science area and the natural gas hydrates research area.

NETL research is contributing to modeling the phase behavior of hydrates in nature.
Hydrates are seen as a possible source of great amounts of natural gas.

The NETL research has added to understanding the formation and stability of hydrates in nature and the impacts of these processes in engineered scenarios.

This work is important in determining the formation and dissociation of methane hydrate in production, climate change, and seafloor stability scenarios and carbon dioxide hydrate in sequestration scenarios when contact is possible with cold, water-containing systems.

The research was published in an article in Industrial & Engineering Chemistry Research in January. The manuscript was coauthored by Dr. Yi Zhang, who received her doctorate degree at the University of Pittsburgh based on this work, which was performed at NETL, Dr. Gerald Holder, US Steel Dean of Engineering at the University of Pittsburgh, who was her research advisor, and Robert P. Warzinski, her mentor at NETL.

The paper describes the formation of hydrate from a hydrate-forming gas dissolved in aqueous solution in the absence of any separate gas or liquid phase of the hydrate former. 

Experimental work was performed with carbon dioxide and theoretical predictions were made for this gas and for methane using a modified thermodynamic model.

NETL’s Laser Spark Plug Operates Smoothly in Tests

	Dr. Steven Woodruff adjusts the NETL laser spark plug to prepare it for installation on the Ricardo single cylinder, large bore engine for testing.

A laser spark plug developed at NETL has overcome one of the barriers to laser distribution through optical fibers.

Researchers in NETL’s Office of Research and Development have completed testing an end-pumped laser spark plug on a single cylinder research engine. The engine was operated on natural gas and also on natural gas augmented by 20 percent volume hydrogen.

In three days of testing, the engine operated smoothly through a range of operating conditions with multiple start-ups and shut-downs. The laser ignition approach can permit engine operation at higher efficiency, and with reduced emissions.

A barrier to laser distribution with optical fibers has been the high laser power required to initiate a laser spark. The spark plug developed by NETL overcomes that barrier in a unique way by utilizing a compact Q-switched laser located at the engine cylinder which is pumped by a diode laser from one end through an optical fiber. 
In this configuration, the laser power delivered is low enough to avoid damage to the fiber.

NETL is working with a CRADA partner to improve packaging and performance of the Q-switched laser and is seeking another CRADA partner to help develop its patented pump energy distribution system.

NETL Leads International Team On CO₂ Brinefield Storage

	Representatives of some of the institutions collaborating on the research include Duane H. Smith, seated, an NETL Geosciences Division Senior Scientist and Adjunct Professor in the Department of Physics at West Virginia University; Dustin Crandall, standing left, a National Research Council Associate at NETL; and Goodarz Ahmadi, Dean of Engineering at Clarkson University, as they examine a flow cell.

Researchers at NETL are leading an international team of collaborators on important research related to geological storage of carbon dioxide and increased oil production.

NETL, West Virginia University of Morgantown, W.V., and Clarkson University of Potsdam, N.Y., have been working together on a program of laboratory experiments, computations, and theory to develop more accurate and reliable equations for describing multiphase flow through porous media. The University of Utrecht in the Netherlands recently joined this effort and is working with scientists and engineers at the other three institutions.

Important applications include injection of water into oilfields to increase the production of petroleum, and injection of carbon dioxide into brine-saturated geologic strata to reduce atmospheric concentrations of carbon dioxide and global warming.

In the first stage of this new collaboration, experiments performed at NETL will provide values of parameters to use in a thermodynamic model of two-phase flow through porous media. The equations for the thermodynamic model previously had been developed in separate work at Utrecht and by the NETL-Clarkson-WVU group. 

Research Suggests Cement Plugs Will Resist Degradation by CO₂

	Barbara Kutchko, a researcher in NETL’s Office of Research and Development, uses a series of high-pressure vessels manufactured specifically for NETL's Geologic Sequestration Core Flow Laboratory. NETL is evaluating the potential for cement degradation to affect storage integrity for geologic storage of carbon dioxide.

NETL research shows that imperfections (air pockets, cracks, etc.) in the cement can lead to significant risk to storage integrity but chemical degradation of cement is unlikely to be extensive enough to present a significant risk to storage integrity of CO₂ under geologic sequestration scenarios.

The results were in excellent agreement with field samples from an enhanced oil recovery site that has been exposed to CO₂ for 30 years.  Both the nature and extent of reaction were as predicted by NETL’s laboratory experiments. 

These findings were presented by NETL researcher Barbara Kutchko at an invited seminar at Princeton University.

The cement used to install and/or plug existing wells is critical in preventing leakage of CO₂ to the surface under geologic sequestration scenarios.  

NETL has conducted laboratory experiments to determine the risk of storage loss due to chemical reaction between CO₂ and cement.  The recent experiment was one year in duration. Results were extrapolated to predict longer term behavior.