Perspectives and Experience With Wet Gas Compression

2016 ◽  
Author(s):  
Grant O. Musgrove ◽  
Melissa A. Poerner ◽  
Griffin Beck ◽  
Rainer Kurz ◽  
Gary Bourn
Keyword(s):  
Oil And Gas ◽  
Liquid Mixtures ◽  
General Definition ◽  
Limited Information ◽  
Process Gas ◽  
Wet Gas ◽  
Gas Compression ◽  
Process Fluid ◽  
Separation Equipment ◽  
Definition Of

In oil and gas applications, gas-liquid mixtures of a process fluid are commonplace and the phases of the mixtures are separated upstream of pump or compressor machinery. Considering compressors, the separation of phases is important because the liquid causes the compressor to operate significantly different than with dry to affect the range, performance, and durability of the machine. Even with separation equipment, liquid can be ingested in a compressor by liquid carryover from the separator or condensation of the process gas. Additionally, there is no single definition of what is considered a wet gas. In this paper, the definition of wet gas from multiple applications is reviewed and a general definition for wet gas is formulated. The effects of wet gas on reciprocating, screw-type, and centrifugal compressors are reviewed to provide insight into how their operation is affected. The limited information for screw compressors is supplemented with multiphase effects in screw pumps.

An Approach to Compact, Wet Gas Compression

2010 ◽  
Author(s):  
Jose´ L. Gilarranz R. ◽  
H. Allan Kidd ◽  
Gocha Chochua ◽  
William C. Maier
Keyword(s):  
High Speed ◽  
Oil And Gas ◽  
Integrated Approach ◽  
Separation Unit ◽  
Compression System ◽  
Wet Process ◽  
Process Gas ◽  
Wet Gas ◽  
Sea Bed ◽  
Gas Compression

In recent years, several papers have been written regarding the use of centrifugal compression technology to handle applications in which the process gas entering the equipment contains a significant amount of liquids, and can therefore be considered a wet gas. One such application that is currently being considered by many oil and gas operators is the installation of processing and compression equipment on the sea bed, to directly handle the process gas stream in close proximity to the wellhead. Other applications also exist topside, in which the operator would benefit from the installation of additional compression and processing capabilities at brown field facilities. Most of these existing installations have limited space for expansion and have strict size and weight limitations that have to be met by the additional equipment. This, in many cases, hinders the utilization of traditional compression and processing equipment, which is typically arranged using the large and heavy multi deck approach. A novel integrated compression system (ICS) has recently been developed to address the current need for compact compression systems that can handle wet process gas. The ICS makes use of centrifugal compressor stages driven directly by a high-speed, close-coupled electric motor, and incorporates a proprietary integrated centrifugal gas-liquid separation unit within the compressor case. This compact compression unit is packaged with process gas coolers in a single-lift module, providing a complete compression system that can be applied to all markets — upstream, midstream and downstream. With this integrated approach, the total footprint and weight of a conventional module or equipment layout can be greatly reduced. This paper is part of a series of publications that will describe the attributes of the new integrated compression system, and will serve to introduce the ICS and the benefits associated to the integration of the centrifugal separator into the compressor casing. The paper will focus on the OEM’s approach to Wet Gas Compression, with emphasis on the benefits of handling the liquid and vapor phases as separate streams, making the system more efficient and reliable than alternate solutions, including the ones that handle the wet gas directly. Finally the paper will provide a comparison between a traditional compression train and the new ICS to show how the latter system offers significant size and weight advantages.

Liquid CO2 Formation, Impact, and Mitigation at the Inlet to a Supercritical CO2 Compressor

2016 ◽  
Author(s):  
Melissa Poerner ◽  
Grant Musgrove ◽  
Griffin Beck
Keyword(s):  
Critical Point ◽  
Oil And Gas ◽  
Critical Parameters ◽  
Ambient Conditions ◽  
Performance Impact ◽  
Two Phase ◽  
Power Cycle ◽  
Wet Gas ◽  
Gas Compression ◽  
Liquid Co2

Cycle efficiency is one of the critical parameters linked to the success of implementing a Supercritical Carbon Dioxide (sCO2) power cycle in a Concentrating Solar Power (CSP) plant application. Ambient conditions often change rapidly during operation, making it imperative that the efficiency of the plant cycle be optimized to obtain the maximum power production when sunlight is available. Past analyses have shown that operating the cycle at the critical point provides the optimum efficiency for dry operation. However, operation at this point is challenging due to the dramatic changes in thermophysical properties of CO2 near the critical point and the risk of the fluid having a two-phase, gas-liquid state. As a result, there is a high likelihood that liquid can form upstream of the primary compressor in the sCO2 power cycle. This paper explores the potential for liquid formation when operating near the critical point and looks at the influence of liquid on the compressor performance. The performance impact is based on industry experience with wet gas compression in power generation and oil and gas applications. Options for mitigating liquid effects are also investigated, such as upstream heating, separation, or compressor internal controls (blade surface gas ejection). The conclusions of the paper focus on the risk, estimated impact on performance, and summary of mitigation techniques for liquid CO2 entering a sCO2 compressor.

Measured Thermodynamic Effect of Wet Gas Compression

2018 ◽  
Author(s):  
Sarah Simons ◽  
Ryan Cater ◽  
Klaus Brun ◽  
Grant Musgrove ◽  
Rainer Kurz
Keyword(s):  
Centrifugal Compressor ◽  
Liquid Volume ◽  
Reciprocating Compressor ◽  
Volume Fractions ◽  
Process Gas ◽  
Wet Gas ◽  
Gas Compression ◽  
Thermodynamic Effect ◽  
Thermodynamic Effects ◽  
Multi Phase

Significant work has been performed to qualify and quantify the effects of operating with wet gas in a centrifugal compressor system [1, 2]. Of particular interest is the sharp decrease in the isentropic efficiency of the machine when operating with process gas containing various liquid volume fractions. However, it is unknown how much of the performance losses are due to aerodynamic effects, such as blade profile and flow separation losses, rather than the basic thermodynamic effects of compressing a multiphase gas that has a higher density, integral wet-cooling, and contains small amounts of high-density droplets. Previous studies showed that the overall efficiency losses exceeded those expected from purely thermodynamic effects so aerodynamic effects have been principally blamed for the lower efficiency. However, no test data exists in the public domain that quantifies these losses and it is experimentally difficult to perform this type of testing in centrifugal compressor. Therefore, a series of tests was performed on a reciprocating compressor with power and efficiency recorded through dynamic pressure measurements obtained inside the compression cylinder, torque measured on the shaft, and enthalpy rise measurements obtained outside the cylinders. Using this approach one can eliminate (or differentiate) the aerodynamic effects of wet gas compression, such as valve losses, thus allowing the direct determination of the thermodynamic losses of wet gas compression. Specifically, when there is multi-phase flow entering the machinery, there is the thermodynamic effect of how a mixture of water and air behaves when being compressed [from a process perspective] and the aerodynamic effect of moisture encountering the blades of a centrifugal compressor [performance loss] or the valve passages of a reciprocating compressor [pressure loss]. Directly instrumenting the internals of a reciprocating compressor cylinder allows the evaluation of the thermodynamic performance of multi-phase compression separate from any aerodynamic penalties. This paper describes the tests performed in a reciprocating compressor open test loop operating with varying amounts of liquid volume fractions (LVFs) of water in the process gas (air). The data was reduced using Pressure-Volume card measurements inside and outside the cylinder, enthalpy rise, as well as torque to determine the impact of volume fraction on compression power and efficiency. Additionally, the valve losses, system efficiencies, and peak compression “spike” were evaluated in relations to the LVFs.

Integrated Wet Gas Compressor Test Facility

2015 ◽  
Author(s):  
Øyvind Hundseid ◽  
Lars E. Bakken
Keyword(s):  
Oil And Gas ◽  
Volume Fraction ◽  
Operating Conditions ◽  
Torque Control ◽  
Test Facility ◽  
Total System ◽  
Wet Gas ◽  
Gas Compression ◽  
Wide Range ◽  
The Impact

The potential production increase from new and existing oil and gas fields worldwide is huge. In some areas, stringent requirements for field recovery specified in the production licence call for the development and utilisation of novel technology concepts. Enhanced recovery may be achieved with wellhead boosting. For specific systems, the booster is preferably installed subsea, either on a single production well or a cluster of these. Development of rotor-dynamic multiphase pumps for topside and subsea applications was initiated at the mid-1980s. A wide range of these pumps are currently installed and in operation worldwide. They typically cover the gas volume fraction (GVF) range from 0 to 0.70. The ability to increase pressure is limited above GVF 0.9, clearly restricting the area of application. In essence, the development of wet gas compressors covering GVFs from 0.95 to 1.0 has been limited to the centrifugal concept, although an axial contra-rotating concept is available. Two new subsea compression systems will be installed, commissioned and in operation from 2015 for the Gullfaks and Åsgard fields on the Norwegian continental shelf (NCS). Their compressors are based on centrifugal and axial technology respectively. Subsea compression is currently being evaluated for several other field developments. The centrifugal compressor has proved to be a robust concept and dominates in the oil and gas industry. Both inert low-pressure and high-pressure real hydrocarbon fluid tests have shown that understanding of the fundamental wet gas compression mechanisms is limited. Evaluating the ability of the centrifugal stage to handle wet fluids has therefore been of specific interest. A wet gas test rig has been designed and built at the NTNU. Its objectives are to validate a wet gas compression system and to determine capabilities and constraints related to the impact of impellerstage performance: • fluid behaviour and dynamics • corrosion and erosion tolerance • surge suppression and stall avoidance • transient operating conditions, including fluctuations in GVF • novel high-precision shaft torque control (static and dynamic) • electric motor and driver response and interactions • total system control. The article focuses on the ongoing test campaigns and related challenges, including test facility design. Understanding the challenges involved is essential for identifying concept constraints at an early stage and ensuring system reliability and availability.

Prospects for Sub Sea Wet Gas Compression

2008 ◽  
Author(s):  
Lars Brenne ◽  
Tor Bjo̸rge ◽  
Lars E. Bakken ◽  
O̸yvind Hundseid
Keyword(s):  
Oil And Gas ◽  
Development Program ◽  
Oil And Gas Industry ◽  
Full Scale ◽  
Gas Field ◽  
Gas Industry ◽  
The North ◽  
Wet Gas ◽  
Gas Compression ◽  
Petroleum Sector

Wet gas compression technology renders possible new opportunities for future gas/condensate fields by means of sub sea boosting and increased recovery for fields in tail-end production. In the paper arguments for the wet gas compression concept are given. At present no commercial wet gas compressor for the petroleum sector is available. StatoilHydro projects are currently investigating the wet gas compressors suitability to be used and integrated in gas field production. The centrifugal compressor is known as a robust concept and the use is dominant in the oil and gas industry. It has therefore been of specific interest to evaluate its capability of handling wet hydrocarbon fluids. Statoil initiated a wet gas test of a 2.8 MW single-stage compressor in 2003. A full load and pressure test was performed using a mixture of hydrocarbon gas and condensate or water. Results from these tests are presented. A reduction in compressor performance is evident as fluid liquid content is increased. The introduction of wet gas and the use of sub sea solutions make more stringent demands for the compressor corrosion and erosion tolerance. The mechanical stress of the impeller increases when handling wet gas fluids due to an increased mass flow rate. Testing of different impeller materials and coatings has been an important part of the Statoil wet gas compressor development program. Testing of full scale (6–8 MW) sub sea integrated motor-compressors (dry gas centrifugal machines) will begin in 2008. Program sponsor is the A˚sgard Licence in the North Sea and the testing takes place at K-lab, Norway. Shallow water testing of a full scale sub sea compressor station (12.5 MW) will begin in 2010 (2 years testing planned). Program sponsor is the Ormen Lange Licence.

scholarly journals DEFINITION AND MEASUREMENT OF RISK IN COMPLIANCE MANAGEMENT

2020 ◽  
Vol 11 (2) ◽  
pp. 150-159
Author(s):  
A. M. Krepysheva ◽  
A. A. Sergievskaya ◽  
M. A. Storchevoy
Keyword(s):  
Risk Management ◽  
Mobile Communications ◽  
Oil And Gas ◽  
Mining Industry ◽  
Oil And Gas Industry ◽  
Organizational Structures ◽  
General Definition ◽  
Compliance Management ◽  
Risk Appetite ◽  
Definition Of

The article is devoted to the problem of defining and measuring risk in compliance management - an important management function of a company aimed at complying with laws and ethical norms. A general definition of risk from the theory of probability and various approaches to understanding risk in the literature on risk management are considered, then the definition of compliance risk and ways to managing this risk in compliance management are explored. The problem of quantitative measurement of compliance risks and some methods of its solution are described. The authors analyze the approaches of several international companies (in the mining industry, oil and gas industry, mobile communications, FMCG) to measuring or assessing compliance risks, as well as organizing compliance risk management in practice (organizational structures, processes, etc.). The work also discussed the concept of risk appetite, that characterizes the willingness of an organization to take on a certain positive level of risk, while logically it is poorly compatible with the concept of compliance risk as a risk of violation of the legislation.

Wet Gas Compression: Test Conditions and Similitude

2017 ◽  
Author(s):  
Dagfinn Mæland ◽  
Lars E. Bakken
Keyword(s):  
Oil Recovery ◽  
Performance Prediction ◽  
Oil And Gas ◽  
Mechanical Design ◽  
Performance Testing ◽  
Volume Ratio ◽  
Centrifugal Compressors ◽  
Wet Gas ◽  
Gas Compression ◽  
Compressor Design

Wet gas compression of gas/condensate/water provides a business opportunity for oil and gas producers. There are several opportunities of particular note: 1) As well tail-end production commences, the installation of sub-sea compressors will provide enhanced oil recovery and, if the subsea compressor is capable of handling liquids, the subsea process complexity can be dramatically reduced, thus decreasing capital investments and possibly operational costs. 2) Topside and Onshore projects can also be dramatically simplified. This is the case for both new installations and modification projects for which wet gas compression is a suitable solution. However, there are several challenges that need to be addressed before wet gas compression, by means of centrifugal compressors, can be considered as a robust commercial solution for future projects. This relates to the robustness of the mechanical design, effects on electrical systems, and issues related to performance. This paper will focus on challenges related to performance prediction and testing. For conventional dry gas compressor design, performance prediction is usually undertaken by the compressor manufacturer, utilising in-house know-how in impeller design and selection. This specialised knowledge is potentially unsuitable for predicting wet gas performance in the design phase; hence, a wet gas compressor design may not meet design requirements specified by the customer. It is typical that agreements on performance testing of centrifugal compressors state that these are to be conducted according to an international standard such as ASME PTC10 or ISO 5389. These standards require that the compressed gas is dry. However, for wet gas compressors, no such internationally established standards exist for performance evaluation. Several of the requirements stipulated in the standards are challenging to apply to wet conditions and they do not ensure similar conditions. Such parameters including the maximum permissible deviation in the specific volume ratio, Mach number and Reynolds number. It is clear that the path towards a standard for wet gas performance testing will require a substantial amount of effort in order to establish new requirements related to wet gas similarity. Based on wet gas compressor test experience, challenges and requirements related to low pressure inert fluid, compared with full pressure actual fluid tests, are analysed and discussed.

scholarly journals A remark on local fractional calculus and ordinary derivatives

2016 ◽  
Vol 14 (1) ◽  
pp. 1122-1124 ◽  
Author(s):  
Ricardo Almeida ◽  
Małgorzata Guzowska ◽  
Tatiana Odzijewicz
Keyword(s):  
Fractional Calculus ◽  
Fractional Derivative ◽  
Short Note ◽  
General Definition ◽  
Local Fractional Derivative ◽  
Fundamental Properties ◽  
Local Fractional Calculus ◽  
Definition Of

AbstractIn this short note we present a new general definition of local fractional derivative, that depends on an unknown kernel. For some appropriate choices of the kernel we obtain some known cases. We establish a relation between this new concept and ordinary differentiation. Using such formula, most of the fundamental properties of the fractional derivative can be derived directly.

scholarly journals AB0677 REVISING THE DEFINITION OF REACTIVE ARTHRITIS AND DIFFERENTIATION FROM UNDIFFERENTIATED SPONDYLOARTHRITIS

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 1633.2-1634
Author(s):  
F. Cosan ◽  
O. M. Gedar
Keyword(s):  
Causative Agent ◽  
Reactive Arthritis ◽  
Case Reports ◽  
Experimental Studies ◽  
Classification Criteria ◽  
General Definition ◽  
Parasitic Infections ◽  
Undifferentiated Spondyloarthritis ◽  
Classical Definition ◽  
Definition Of

Background:Reactive arthritis (ReA) is defined by 1999 ACR criteria as arthritis preceding a bacterial genitourinary (GUS) or gastrointestinal (GIS) infection in 3 days-6 weeks and evidence of triggering infection. Recently, ReA is classified as SpA and patients who do not fulfill SpA criteria are classified as undifferentiated spondyloarthritis (USpA) according to ASAS/EULAR SpA classification criteria.Objectives:In several case reports which are associated with other infective agents are reported and the definition is extended for some clinicians so that SpA which is occurred after any infection is called as ReA. On the other hand, some researchers still accept the classical definition of ReA. The problem with the heterogeneity of opinions and unstandardized definition of ReA hinders studies about pathogenesis and standardization of treatments. In this study, we aimed to determine the spectrum of the use of the definition of reactive arthritis in publications in PubMed between 2009-2019.Methods:The ReA keyword is searched in PubMed for the years between 2009-2019. 248 different publications have been identified and included in this research. 89 articles, 47 reviews, 108 case reports, 2 guidelines, and 2 editorials reviewed for the definition of ReA.Results:Only 42.7% (106 patients) of these publications meet the classical definition which suggests ReA after only GIS and GUS infections. In 4 (1.6%) of the publications ReA was defined after GIS, GUS and oropharyngeal infections; in 3 (1,2%) of the publications after any bacterial infection; in 9 (3.6%) of the publications after any infection. In 8 (3.2%) of the publications, ReA and USPA was used correspondingly. In 39 (15,7%) of the publications the term agent related, ReA was used without making a general definition for ReA. 79 publications (31,9%) have not defined ReA.According to causative agent and ReA relationship, in 64 (24,6%) general infective agents, in 75 (30,2%) classical agents, in 22 (8,9%) other bacterial agents, in 23 (9,3%) streptococcus, in 10(4%) intravesical BCG, in 6 (2.4%) HIV, in 6 (2.4%) tuberculosis, in 12 (4,8%) clostrudium difficle, in 2 (0.8%) parasites were reported. In 31 (12,5%) of the publications the causative agent for the ReA was unknown, the diagnosis was made clinically.Conclusion:In this study, it is aimed to draw attention terminology intricacy and the need for the standardization of the definition of ReA and USpA. It is clear that to standardize the definition of Rea and USpA is necessary. Between 2009-2019 there are reported cases diagnosed as ReA associated with bacterial infections (especially with Clostridium difficile, streptococcus and tuberculosis infections), and viral infections (by a majority with HIV), and parasitic infections. It is not clear if we need to define them classically or define them as USPA. Another important consideration is the necessity of extended laboratory investigations to find out the real causative agent even if the patient is clinically diagnosed with ReA. The requirement of the differentiation between ReA and USpA must be revealed for therapeutic researches.References:[1]A proposal for the classification of patients for clinical and experimental studies on reactive arthritis. Pacheco-Tena C, Burgos-Vargas R, Vázquez-Mellado J, Cazarín J, Pérez-Díaz JA. J Rheumatol. 1999 Jun;26(6):1338-46.[2]The Assessment of SpondyloArthritis International Society classification criteria for peripheral spondyloarthritis and for spondyloarthritis in general. Rudwaleit M, van der Heijde D, Landewé R, Akkoc N, Brandt J, Chou CT, Dougados M, Huang F, Gu J, Kirazli Y, et al. Ann Rheum Dis. 2011;70:25–31.Disclosure of Interests:None declared

scholarly journals A lattice-theoretic characterization of pure subgroups of Abelian groups

2021 ◽  
Author(s):  
M. Ferrara ◽  
M. Trombetti
Keyword(s):  
Abelian Group ◽  
Abelian Groups ◽  
Subgroup Lattice ◽  
General Definition ◽  
Short Paper ◽  
Theoretic Characterization ◽  
Definition Of

AbstractLet G be an abelian group. The aim of this short paper is to describe a way to identify pure subgroups H of G by looking only at how the subgroup lattice $$\mathcal {L}(H)$$ L ( H ) embeds in $$\mathcal {L}(G)$$ L ( G ) . It is worth noticing that all results are carried out in a local nilpotent context for a general definition of purity.

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