Overview of Important Considerations in Wet Gas Compression Testing and Analysis
During upstream production of natural gas fields, it is common that a gas-liquid mixture of product is brought to the surface. The mixture, termed wet gas, is generally made up of mostly gas with a small amount of liquid, typically up to 5% by volume of the mixture. Because of the difficulties of compressing wet gas, the practical approach has been to separate the liquid and gas phases before compression. However, large separation equipment is unfavorable for subsea installations because of the cost to place machinery on the sea floor. Instead, a compressor designed for wet gas operation is preferred because it eliminates the need for large separation equipment leading to plant simplification and cost reduction. To address this design need, researchers have been active in addressing the challenges with wet gas compression. As result, experimental work has been conducted to study the effects of wet gas on compressor aerodynamic and mechanical performance. This experimental research has presented many challenges in recreating wet gas conditions and quantifying the effect of the liquid on the compressor performance. The results from this testing have helped to characterize the performance effects. But so far each work has focused on a range of test variables without identifying those that have the largest effect on compressor performance. This paper aims to provide the reader with an overview of the completed wet gas research, the challenges associated with doing the experimental work, and a discussion of the resulting trends observed in most of the wet gas research. This will include an in-depth review of relevant literature on wet gas compression testing and performance, a discussion of the important
An Investigation of the Use of Wet Compression in Industrial Centrifugal Compressors
Industrial centrifugal compressors generally comprise a number of low pressure ratio intercooled stages. This is done primarily for the purpose of reducing the compressor power requirements and improving the operating range of the multi-stage compressor. In recent years, however, rapid increases in the per-kilowatt-hour prices both domestically and worldwide has led to renewed research efforts to further reduce the power requirements of this type of compression equipment. Several attempts have been made to use direct water injection as a means to overspray the compressor inlet to further reduce its power requirement. This paper presents an investigation into the use of this technology in industrial centrifugal compressors. A simple numerical method is presented for the computation of wet compression processes. The method is based on both droplet evaporation and compressor mean-line calculations. An assessment, based on the developed model, of the effectiveness of evaporative processes in reducing the compressor power consumption per stage is presented. The impacts on stage efficiency and operating range are also presented.Copyright © 2006 by ASME
Mechanics of deformable directed surfaces
Abstract The paper develops a simple, yet complete and consistent non-linear dynamic thermo-elastic shell theory based on the concepts of a two-dimensional directed continuum. The constitutive equations are postulated in a general form. Stress-strain relations are derived using the equation of energy balance and the two entropy production inequalities, which are rewritten in a special form. The linear theory is discussed in detail. The structure of the stress-strain relations is presented in the most general form and then specialized to concrete examples, in particular, to the classical shell theory, using their invariance properties with respective to certain symmetry groups. The elastic moduli are determined by demanding the coincidence of the frequency dispersion surfaces obtained using the two-dimensional theory with the lowest foils of the corresponding surfaces resulting from the three-dimensional theory of elasticity.