Oil Free Compression on a Natural Gas Pipeline

Oil entrainment in the natural gas stream together with maintenance associated with oil systems have been long standing problems in booster compressors on a natural gas pipeline system. The use of dry gas shaft seals and active magnetic bearings will effectively eliminate the use of oil systems in gas compression. The paper will deal with the history of TransCanada PipeLines’ past experiences with oil eliminating devices, the theory of dry gas seals and magnetic bearings, the effects on rotor dynamics of magnetic bearings and the recent installation of a set of seals and bearings in a booster compressor unit, in service on the TransCanada PipeLines system.

Thermal Stability Concerns of Navy Aviation Fuel

The U.S. Navy’s concerns about the thermal stability of aviation fuel stem from a combination of increased performance requirements of engines and potential degradation in fuel quality. The results of recent atomizer fouling tests with hot fuel are presented. These are combined with similar results from Air Force programs and analyzed with respect to the impact on engine performance and reliability.

Gas Turbine Uses Coal Fuel With Indirect Heat Transfer via Circulating Ceramic Beads

This paper defines a gas turbine power system in which the heat from coal combustion is transferred to a clean working gas by contact with a recirculated stream of hot ceramic beads. The beads are first heated by direct contact in a pressurized coal combustion zone and then the hot beads are separated, freed of coal ash and contacted directly with a pressurized gas such as air going to a gas turbine. Separate zones are used for combustion and for contact with the clean gas to be heated, and these two zones are kept separated by an intermediate column of beads at each transfer point. Similar technology is well known and used commercially in the petroleum industry, for example, in catalytic cracking of oil to make gasoline. Hot clean gas from the operation is used to generate power in an expander, while the products from coal combustion are handled by conventional methods for environmental control. The system offers the simplicity and efficiency typical of gas turbines and avoids the large use of water typical of steam power systems. Low investment is expected, together with minimal environmental impact.

Trends in Design and Development of Mechanical Drive Power Turbines

The power turbines that are used with aero-derivative gas generators have been upgraded in response to performance improvements in these gas generators. The manner in which power turbine designs have evolved to cope with higher temperatures and greater work extraction levels is explained. The test program for the latest design is described and typical performance and mechanical development results are presented.

The Application of a Unique Flow Modeling Technique to Complex Combustion Systems

This paper describes the application of a unique three-dimensional water flow modeling technique to the study of complex fluid flow patterns within an advanced gas turbine combustor. The visualization technique uses light scattering, coupled with realtime image processing, to determine flow fields. Additional image processing is used to make concentration measurements within the combustor.

A Model for Bluff Body Flame Stabilization

Previous work on bluff body stabilization mechanisms is reviewed, and existing models are categorized in tabular form, showing the underlying assumptions and resulting equations. Lacunae in existing models are discussed, particularly their reliance on characteristics such as laminar flame speed which is difficult to predict for the conditions encountered in turbojet afterburners. A model for bluff body flame stabilization is proposed based on the stirred reactor approach. In addition to the effect of temperature, pressure and geometry, it includes chemical effects such as vitiation and fuel-air equivalence ratio. Blow off velocities predicted by the model are compared to experimental data for various conditions.

Design and Testing of an Ultra-Low NOx Gas Turbine Combustor

The design and initial rig testing of an ultra-low NOx gas turbine combustor primary zone are described. A lean premixed, swirl-stabilized combustor was evaluated over a range of pressures up to 10.7 × 105 Pa (10.6 atm) using natural gas. The program goal of reducing NOx emissions to 10 ppm (at 15% O2) with coincident low CO emissions was achieved at all combustor pressure levels. Appropriate combustor loading for ultra-low NOx operation was determined through emissions sampling within the primary zone. The work described represents a first step in developing an advanced gas turbine combustion system that can yield ultra-low NOx levels without the need for water injection and selective catalytic reduction.

Modelling of Component Faults and Application to On-Condition Health Monitoring

Fault matrices can be predicted for any gas turbine, making use of well established component matching techniques and corrections for component deterioration. Quantification of deterioration levels is difficult and more than one component may be subject to in-service deterioration. Computer models of a twin-spool gas generator have been used to predict the effects of varying levels of component performance loss, and these are used to evaluate fault matrices for use with engines in the field.

Erosion and Corrosion Considerations for PFBC Gas Turbine Expanders

Considerable interest has been developed over the past few years in the application of gas turbines to expand the hot, dirty flue gases from pressurized fluidized-bed combustors (PFBCs) burning coal. Although no full-size gas turbine has yet operated on a PFBC, firm commitments have been made to build commercial PFBC-GT power plants. In addition, there are a number of projects at various stages of development aimed at operating gas turbines on dirty fuels ranging from the expansion of flue gas from the combustion of pulverized coal, to the direct firing of coal-water mixtures. Common concerns of all these applications include erosion and corrosion of the gas turbine hot gas path components. This paper attempts to provide an overview of results of research and testing so far reported in these areas, and to make an assessment of the engineering trade-offs required for the successful operation of PFBC gas turbine expanders.

Simulation of the Heat Transfer in a Gas Turbine Combustor Fueled With Coal-Water Mixture: Part 1 — Model Development and Verification

It is possible to disperse high concentrations of finely pulverized beneficiated coal in water to produce a stable coal-water slurry fuel (CWF). One of the potential applications of CWF is as a fuel in gas turbines. This represents a relatively novel, developing technology. Coal beneficiation to the level needed for gas turbine application (< 1 percent ash) requires fine grinding of the coal particles to less than 15 μm necessitating increase in water content of the slurry to avoid increased CWS viscosity due to the finer particles. The gas turbine cycle is capable of accommodating an increased water content of the fuel without a significant loss in efficiency. The objective of the present study is to develop and verify a computer model to simulate the heat transfer processes taking place in a gas turbine combustor (GTC) burning a CWF. The model predicts the species and the temperature distribution throughout the GTC, the heat flux patterns and the contribution of both convection and radiation to the total heat transfer rate. Model verification includes cases of cold flow without combustion, combustion without heat release, combustion without convection and/or radiation, verification of exchange areas and an overall energy balance check.