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.

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.

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.

Development of a New Hot Gas Double Axial Valve and Design Concept for a Coaxial Valve

The hot gas double axial valve is a newly developed shut-off valve for high temperature and high pressure helium, which can be used in the new generation of helium cooled nuclear plants, including the modular reactor. It is the safety shut-off valve in the secondary circuit after the heat-exchanger. At first it will be used in the German project PNP (nuclear process heat for the gasification of coal), but it can also be used for the other high temperature systems such as the closed cycle nuclear gas turbine, chemical plants or for industrial processes. Its state of development, test results, and the present prototype design are discussed. A further concept for a coaxial valve will be shown, which may be of interest for certain types of modular reactors and also for closed cycle nuclear gas turbines.

Electricity From Coal: The British Gas/Lurgi Gasification for Combined Cycle Power Generation

It is widely accepted that coal gasification combined-cycle plants represent an environmentally superior alternative to conventional coal fired power plants with flue gas desulfurization. Purpose of this paper is to show that technology is available for all steps required to convert coal to electricity, including treatment of waste streams. Based on examples for power plants in the 200–800 MW range using current and as well as advanced gas turbines, it is shown that under both European and US-conditions cost of electricity from this (new) route of coal based power generation is certainly no higher — and probably even lower — than from conventional PC (pulverized coal) power plants equipped with equivalent environmental control technology. Thus, this technology is likely to be a prime contributor when it comes to enhance environmental acceptability of power plants in general, and to help solve the acid rain problem in particular. In addition the versatility of the proposed technology for repowering, decentralized application and district heat system is explained.

Correlation of Pneumatic Particle Erosion With the Micro-Mechanical Properties of a High Temperature Alloy

Although reasonable correlation may be obtained between the pneumatic particle erosion behavior of many metals and alloys with corresponding hardness measurements, this relationship does not necessarily agree at elevated test temperatures. It is shown that, for the case of a Ti-6A1-4V alloy, there is a significant difference when both the erosion and the hardness tests are conducted at temperatures above and below about one-half of the absolute melting temperature of this alloy. This circumstance, at the present time, is attributed to the change in the ductility of the alloy with test temperature. It is also shown that a measure of the strength and ductility may be obtained from the elevated temperature hardness measurements. A preliminary model relating the erosion rate with the strength and uniform elongation obtained through microhardness measurements is presented.