Gas Pumping Units Research Articles

AUTOMATED EMERGENCY SHUTDOWN SYSTEM OF A GAS PUMPING UNIT

Automated emergency stop system for gas pumping unit has been developed and tested. Block diagram of stop system has been charted and control program has been written. HMI-interface of operator control panel has been developed.

Behavior of Operational Depletion of Strength Characteristics of Gas Pumping Unit Turbine Disk Materials for Different Lifetime

The analysis of the initial level and kinetics of the mechanical characteristics depletion of the EI698-VD alloy was performed depending on the lifetime of the NK-family turbofan disks operating as a part of gas pumping units.

Комбінований метод нечіткої кластеризації даних в системах технічної діагностики

У статті наведено результати аналізу методів нечіткої кластеризації даних поточних спостережень в технічних системах. Запропоновано і протестовано комбінований підхід до нечіткої кластеризації даних з використанням комбінації алгоритму Густафсона-Кесселя, методу остовного лісу та фільтра Калмана, що може бути використаний в системах технічної діагностики (зокрема, діагностики стану основних параметрів технологічних процесів). Розглянуто можливість подальшого розширення функціональних можливостей наведеного комбінованого методу кластеризації з наданням йому адаптивних властивостей. Наведено результати тестування та визначено переваги запропонованого підходу.

Загальна оцінка потенціалу скорочення викидів парникових газів у нафтогазовій галузі України на період до 2040 року

We present the results of analysis of the state of greenhouse gas emissions in the oil and gas industry according to data of the last National Inventory Reports. It was shown that industry is a great source of methane leakage, responsible for 44% of total country's methane emissions in 2017. Carbon dioxide emissions from the industry make a marginal contribution to total country's carbon dioxide emissions, responsible for only 3% in 2017. It was established that the main priority for oil and gas industry is the reduction of methane emissions from natural gas activities, which is typical for gas industries in other countries. The experience of national and international programs and initiatives aimed at reducing methane emissions from oil and gas operations were used for forming the lists of measures and technologies advisable for introduction in Ukraine, concerning the hydrocarbons exploration, development, and production as well as their preparation to transportation, activities for the natural gas transportation and its underground storage, activities for the natural gas distribution and its consumption by the residential and commercial sectors. The necessity to solve in Ukraine the problem of monitoring of methane emissions and leakages in the oil and gas sector, which requires the improvement and standardization of their quantification, reporting, and verification, is mentioned separately, but this problem is not completely solved in any country of the world, which is connected with certain peculiarities of emissions sources. The article provides a comparative analysis of the results of cost calculations for the services of main pipeline transportation of natural gas with replacing existing gas-turbine gas pumping units by new gas-turbine or electric drive units. We present the external conditions for development of the oil and gas industry, for which overall estimates of greenhouse gas emissions by 2040 are calculated for two formed scenarios – with and without measures for emission reduction.

Выбор параметров и конструкции приводной ГТУ с воздушной турбинной теплоутилизирующей установкой в составе ГПА мощностью 16 МВт

The introduction of combined turbine units is a promising method to increase fuel efficiency (pumped natural gas) and improve the environmental performance of the gas turbine units (GTU) that are used to drive superchargers of gas pumping units (GPU). Such an installation consists of the main GTU operating on natural gas and an additional air turbine unit (ATU). The latter utilizes the heat of the combustion products leaving the gas turbine unit in a heat exchanger, behind which cooled air is mixed with flue gases. The efficiency of heat recovery is determined by solving a complex technical and economic problem of selecting the optimal weight-and-size parameters of the heat exchanger. When retrofitting a gas pumping unit, it is advisable to use a GTU that is slightly different in design and parameters as the basic gas turbine unit. The ATU does not have an operating equivalent. Its parameters should ensure achieving the maximum fuel efficiency factor of the combined installation, with acceptable weight-and-size parameters of the ATU and the heat exchanger. As an example of developing the GTU-ATU type installations, an option of modernizing a GTU for a 16 MW GPU is proposed, which constitutes the basis of the Gazprom fleet. A combined GTU-ATU is designed to include the main 16 MW GTU and an additional 1 MW ATU to drive the electric generator. The fuel efficiency factor of the GTU-ATU installation reaches 39.3%. The design of the developed ATU is simple and reliable. Plate-ribbed surfaces PlR-2/PlR-2 are used to achieve the optimum mass-and-weight and hydraulic parameters of the heat exchange. A layout of the units of the combined installation is proposed, in which acceptable hydraulic resistance in the pipelines is provided. The feasibility study shows that the project is economically feasible. The environmental effect of modernization using an ATU is characterized by a significant decrease in the temperature of flue gases and concentration of harmful emissions by 1.3 times.

КОНЦЕПЦИЯ ПРИМЕНЕНИЯ КОМПОЗИЦИОННЫХ МАТЕРИАЛОВ ДЛЯ ОПТИМАЛЬНОГО ПРОЕКТИРОВАНИЯ ОСЕВОГО ВЕНТИЛЯТОРА СИСТЕМЫ ОХЛАЖДЕНИЯ ГАЗОТУРБИННОЙ УСТАНОВКИ В СОСТАВЕ ГАЗОПЕРЕКАЧИВАЮЩЕГО АГРЕГАТА «УРАЛ»

The concept of the use of composite materials (СM) for the optimal design of an axial fan (AF) for the cooling system of a gas turbine installation (GTI) as part of the Ural gas pumping unit (GPU) is proposed. GPU of the Ural series developed by PJSC “Research and production association ”Iskra” are intended for the reconstruction of existing and equipping newly built workshops of compressor stations (CS) of gas pipelines, booster compressor stations (BCS), and underground gas storages (UGS). GPU depending on power are equipped with gas turbine units (GTU) based on aircraft or ship engines. The types and manufacturers of compressors used are determined by the purpose of the unit and the required characteristics. A weak link in the design of the AF is the high sensitivity of the impeller to impact axial load and the low adaptability of its production and repair. Thus, in the studied axial high-load fan system, the authors proposed a technology for manufacturing impeller vanes from metal and coatings from CM. The design of the AF with a coaxial arrangement of industrial blades has a number of its own characteristics. Fiberglass and non-ferrous metals, aluminum alloys and a brushless electric motor with rolling bearings are widely used in the designed design. In the developed AF design, the blades of its impeller can be oriented at different angles of attack, forming a different range of aerodynamic characteristics. A series of computational experiments was carried out to determine the aerodynamic and strength characteristics of the AF. In accordance with the results of numerical modeling and experimental testing at the stand, the performance of the AF structure was confirmed.

The Implementation of the Encapsulated Electric Driven Gas-Pumping Units At the Facilities of Jsc «Gazprom»

Invention proposes analysis of electric drive structures with alternating current machines of megawatt class for integrated versions of oil and gas industry units. The main advantages of encapsulated machines in electric drives of gas pumping units were reviewed. Features of integrated electric motors with turbocompressors on main gas pipelines of Russia are considered. The main advantages of new single-body units are analyzed - direct connection "engine-supercharger" on the basis of high-speed electric machines, exclusion from the arrangement of multiplier units, application of magnetic suspension of rotors, elimination of lubrication system and seal maintenance systems, reduction of probability of occurrence of emergency modes and surge, improvement of energy indicators and dynamics, significant reduction of areas for installation of units. Intelligent system of automatic control of encapsulated electrically driven units and examples of projects of modernization of electrically driven compressor stations on main gas pipelines of Russia are presented. Effective results of implementation of non-reductive and oil-free technologies to increase functional capabilities, reliability, resource, energy efficiency and environmental friendliness of the most important electromechanical systems in the fuel and energy complex of the country are shown.

Mode diagnostics of pipeline systems of the energetics

The paper proposes a method for diagnosing gradual failures in pipeline power systems, based on tracking the dynamics of flow regime parameters. The method also makes it possible to promptly adjust the coefficients of a mathematical model of the system objects. Conclusions are made based on the analysis of the entire set of measurements, which are considered random variables due to measurement errors. Conclusions are made based on the analysis of the entire set of measurements, which are considered random variables due to instrumental errors. Examples of a gas pumping unit and a complex looped gas pipeline system are given. Calculations are performed using standard software.

Estimation of the driven gas turbine unit technical performance using the standard measuring systems

In large pipeline gas transport systems the operation and maintenance of gas pumping units are carried according to the current number of equivalent working hours of centrifugal gas compressors and gas turbines. Modern terms of lean production require the maintenance procedure to be done according to the current technical performance of equipment. The paper presents a designed and verified methodology of technical performance estimation of gas turbine units using the standard measuring systems. This method includes a verified high-order mathematical model based on the gas dynamic function for the precise analytical description of turbomachinery aerodynamics. The models are defined for different types of multi-shaft gas turbines. In this article the results of technical performance estimation of different gas turbine units are discussed.

Modeling of the modes of natural gas transportation by main gas pipelines in the conditions of underloading

The current state of transit of natural gas through the Ukrainian gas transmission system (GTS) is estimated in the paper. The prerequisites for further reduction of the GTS load in the coming years are considered, in particular in the direction of Europe through the gas measuring station "Orlivka" (south direction), taking into account the construction of alternative bypass gas pipelines. On the basis of the review of literature sources on the problem of efficient operation of gas pipelines under conditions of underloading, a method for determining the capacity and energy consumption of the gas pipeline for a given combination of working gas pumping units (GPU) was developed. The Ananyev-Tiraspol-Izmail gas pipeline at Tarutino-Orlivka section was selected as the object of research. The methodology includes the calculation of the physical properties of gas by its composition, the calculation of gas compression, the calculation of the linear part, the gas flow to the compressor station's own needs, and the calculation of the total power of the gas-pumping units under the specified technological limitations. With the help of the original software developed in the MATLAB programming language, cyclical multivariate calculations of the capacity and energy consumption of the gas pipeline were carried out and the operating modes of the compressor shop were optimized in the load range from 23 ... 60 million m3/day. Optimization criterion is the minimum total capacity of the GPU. Variable parameters at the same time are the speeds of the superchargers, different combination of working GPU, load factor. According to the results of the optimization graphical dependences were constructed: the optimum frequency of the rotor of the supercharger on the performance of the pipeline; changes in power and pressure depending on the performance of the pipeline when operating a different combination of superchargers. Recommendations have been developed to minimize fuel gas costs at the compressor station.

INVESTIGATION OF THE AMPLITUDE STABILITY RELATION OF A MATHEMATICAL MODEL OF A CENTRIFUGAL PUMP OF A PUMPING UNIT AS AN OBJECT OF CONTROL WITH A DEGREE OF GAS PRESSURE

Using the experimental data obtained intheprocesso fchange inthetime of the degree of increase in gas pressure, as well as the performance of the centrifugal supercharger of the gas pumping unit, . Digitization of graphs of change of degree of increase of pressure of gas, and also productivity of the centrifugal supercharger of gas-pumping unitis made with the help of software Graph2Digit. The digitization wasper formed with a sampling period of 0.3 s. The number of values forth edegree of increase of gaspressure, as well as the performance of the centrifugal pump gas pumping unitis 581 each.
 The experimental data are divide dinto ranges (1 - 811 sec - 818 sec; 2 - 818 sec - 825 sec; 3 - 811 sec - 831 sec; 4 - 825 sec - 831 sec; 5 - 827 pp. - 832 pp .; 6 - 829 pp. - 831 pp.). In the course of the study, the mathematical expectation for each of the intervals, as well as the spectral density equation for the degree of gas pressure increase and the spectral density equation for the performance of the centrifugal supercharger of the gaspumping unit, were determined at appropriate intervals.
 Using there lation between the spectral densitiesand the fact function of the Matlab software product, which factorizes fractional-rational expression, the gear function saredetermine date achinter valand the stability stocks are determine dusing the Nyquist criterion.
 The plot of the stability reserve of the centrifugal supercharger of the gas pumping unit as an object of control from the mathematical expectation, which is obtained on the basis of the spectral density ratios, is made. This dependency is approximated by the CurveExpert Professional software to select the optimalma them at icalmodel.
 From the set of results, the one with the high estcorrelation coefficient and the small eststandard error isselected.

METHOD OF ESTIMATING THE TECHNICAL STATE OF THE COMBUSTION CHAMBER OF A GAS TURBINE INSTALLATION ON THE BASIS OF ARTIFICIAL INTELLIGENCE

Reliable and efficient operation of the gas-pumping unit to a large extent depends on the technical state of the combustion chamber. The poor technical state of the combustion chamber reduces not only the efficiency of the gas pumping unit, but also increases the harmful emissions to the environment of harmful substances such as nitrogen and carbon oxides. Therefore, the determination of the technical state of the combustion chamber by the results of observations on the operation of the gas turbine installation is an actual scientific task.
 As a result of the analysis of literary sources and experimental studies, it is established that the mediated parameters characterizing the technical state of the combustion chamber are the total concentration of nitrogen oxides and the mean square value of the vibration velocity of the combustion chamber body. Over time, the elements of the combustion chamber are degrading, which leads to a change in the signs of the technical state of the combustion chamber. Indicators of a technical state form a plane of signs, which, with the help of the neural network Kohonen, are divided into three areas, each of which corresponds to a certain technical state of the combustion chamber - "good", "acceptable", "permissible". A method for constructing separate curves based on genetic algorithms is developed to distinguish the areas of technical states. The equation of separate curves is taken as a polynomial of a certain degree. The developed method on the basis of the class separation criterion determines not only the parameters of the equation of a separate curve but also the structure of such an equation by minimizing the class separation criterion. With the help of the developed software of the task of the technical condition assessment of the combustion chamber, the plane of the signs is divided into three classes and separate split curves are constructed.

Use of compressed gas heat utilizers in gas-compressor units

The study considers the possibility of using the Ranque-Hilsch vortex tube in the construction of a heat exchanger for heating fuel gas to ensure normal operation of the gas-pumping units used to pump gas into the underground gas storages. According to the results of the gas-hydrodynamic and thermal methods for calculating structural elements, a final equation was obtained describing combined operation of the vortex tube and heat exchanger. The calculation method allows taking into account the impact of the main temperature and design parameters. The results of technical and economic calculations and thermal modeling based on the SOLIDWORKS program make it possible to judge the effectiveness of the proposed design.

Analysis of energy characteristics of absorption water-ammonia refrigeration machines in the waste heat recovery systems of gas turbine installations on gas main pipelines

One of the promising ways to reduce operating losses in main gas pipelines is pre-cooling of compressed gas using heat-using absorption water-ammonia refrigeration machines (AWRM), which utilize the waste heat of the exhaust products of the combustion of gas pumping units. The object of research is the energy characteristics of the AWRM in a wide range of operating parameters (outdoor temperatures), which are currently not studied. A methodology for modeling AWRM modes is developed, analytical studies are conducted and the results are obtained in a wide range of outdoor temperatures. The study is conducted using theoretical analysis of AWRM cycles in a wide range of outdoor temperatures and temperatures of the cooling object. The analysis of the calculation results showed that in the range of design parameters there is a maximum energy efficiency AWRM. The most obvious is the presence of a maximum for operating conditions at cooling medium temperatures of 20…32 °С and low temperatures of the cooling object (minus 25 °С). As the temperature of the cooling object decreases, the maximum energy efficiency shifts to the region of high temperatures of the heating medium, and its numerical values decrease. At heating source temperatures from 90 °С to 130 °С, the electric power of the circulation pump has a maximum value. Subsequently, with an increase in the temperature of the heating source, its asymptotic decrease and slow decrease are observed. In this case, the greatest changes occur at elevated temperatures of the cooling medium (32 °С). The simulation results allow to determine the most energy-efficient operating modes of the AWRM with various sources of thermal energy (temperatures from 90 to 160 °С) and to develop cooling systems for a wide temperature range (minus 30…15 °С). To achieve such optimal conditions, an appropriate combination of the composition of the working fluid and the temperature of the heating source is necessary.

Повышение эффективности газоперекачивающих агрегатов: проблемы и решения

The paper describes the process of initiating a project to improve the efficiency of gas turbine plants for driving centrifugal superchargers at compressor stations. The study shows the main trends of increasing the efficiency of gas turbine drives of gas pumping units, gives the constructive-functional appearance of the modern gas turbine drive of the gas pumping unit, and proposes a method for increasing its efficiency.

EVALUATION OF THE PROSPECTS FOR PRELIMINARY COOLING OF NATURAL GAS ON MAIN PIPELINES BEFORE COMPRESSION THROUGH THE DISCHARGE OF EXHAUST HEAT OF GAS-TURBINE UNITS

For the transportation of natural gas through pipelines, gas pumping units (GPU) are installed at numerous compressor stations (CS), the energy carrier for which, in most cases, is transported natural gas. 0.5 ... 1.5 % of the volume of transported gas is consumed (burned) by the pumping unit drive. The situation with the replacement of existing equipment with modern equipment is associated with significant investments, on the one hand, and the uncertainty with the transit of Russian natural gas through gas transmission systems of Ukraine in the near future. More promising is the way to increase the efficiency of the GPU cycle through the use of circuits with preliminary cooling of the compressed gas. The aim of this research is studying the prospects for the application of technology for pre-cooling technological natural gas before compression in a gas pumping unit based on heat-using absorption refrigeration machines. To analyze the effect of pre-cooling of technological natural gas on the compressor stations of main gas pipelines, gas pumping units – GTK-10I were selected. The calculation of GPU power consumption and fuel gas consumption at various temperatures of the process gas at the inlet to the supercharger was performed. The calculation of the operating parameters of the gas pumping unit is performed and the energy and financial prospects of the technology for cooling the process gas before compression in the GPU CS are shown. For the current economic situation (July 2019) in the Ukrainian gas market, the daily decrease in operating costs in standard gas pipelines with a decrease in gas temperature before compression in the gas pumping unit by 20 K ranges from 1800 USD to 3360 USD. A scheme of a recycling plant based on absorption water-ammonia refrigeration machine (AWRM) is proposed, which in the range of initial data allows to reduce the temperature of technological natural gas before compression by 11 ... 13 ° C.

Development of a method for optimizing operation of centrifugal gas superchargers under conditions of uncertainty

A problem of development of a method of optimal control of operation of natural gas superchargers by a criterion which both minimizes fuel gas consumption and takes into account power of nitrogen oxide emissions into atmosphere has been formulated. Technical conditions of gas pumping units, restrictions on technological parameters and the requirement to provide a planned indicator of gas pumping by a group of parallel-operated superchargers were taken into consideration. Technical condition of each unit or its assembly is assessed based on certain attributes. If observation of such attributes is made for a certain period of time, a set of attributes is obtained. Using an artificial neural network of Kohonen type, the set of attributes (images) is divided into three classes. A certain number of points is assigned to each class. This number characterizes technical condition of the class. The number of points assigned determines utilization of each supercharger. This is taken into account when limiting overall performance of the supercharger group. Formalized record of the optimal control problem contains dependences that are approximated by a polynomial of a specified order. This results in an empirical model whose structure is determined using an apparatus of genetic algorithms. For a series of reasons (errors in measuring technological parameters, errors in measurement methods, external effects, limited scope of experimental material, etc.) identification of values of empirical model parameters is based on inaccurate information. Therefore, parameters of empirical models are treated as fuzzy quantities. Based on the adopted concept, a formalized record of the problem of optimal control of operation of natural gas superchargers was obtained. Implementation of the study results will help save fuel gas and reduce nitrogen oxide emissions into environment

Применение воздушных турбинных теплоутилизирующих установок для модернизации газоперекачивающих агрегатов с газотурбинным приводом

One of the urgent tasks of further developing natural gas transportation systems is the need to increase fuel efficiency and to improve environmental performance of the gas turbine units (GTU) that are used to drive superchargers of gas pumping units. Outdated GTUs with low efficiency are being replaced by units of a new generation, including those of the regenerative cycle. However, this requires significant capital expenditures, thus, the possibilities of upgrading the existing units are also being investigated. A significant proportion of the energy generated by the gas combusted in driven GTUs is lost in the form of heat of the exhaust combustion products. These gases have a temperature not lower than 670 K. To utilize the heat of the exhaust combustion products, it is proposed to compliment the main GTU by an air turbine heat recovery unit (ATU) that is simple in design and inexpensive in production. This well-known idea has not yet been realized in practice, thus there are no recommendations on the use of a GTU-ATU as a drive for natural gas superchargers. It is shown that to ensure the possibility of upgrading drive gas turbines at a minimum cost, it is advisable to use an ATU that is kinematically independent of the GTU. The ATU’s power is used to cover the own needs of the compressor station and other purposes. The calculations show that under equal conditions, the combined GTU-ATU is inferior in efficiency to the GTU of the regenerative cycle. However, it provides a much smoother flow of the efficiency parameter depending on the operation mode, which is important for gas pumping units. The potential of using the ATU for the modernization of drive GTUs is estimated. It is noted that in addition to generating additional power, the use of ATU’s can decrease the flue gas temperature and the mass concentration of harmful emissions.

OPTIMIZING THE MODES OF COMPRESSOR STATIONS UNDER THE CONDITIONS OF THEIR PARTIAL LOAD

The principle of construction of stochastic and deterministic mathematical models for prediction of operating modes of gas pumping units at compressor stations of main gas pipelines and their optimization in conditions of incomplete loading of the gas transmission system is proposed. Calculation of the parameters of the technological mode of operation of the compressor stations of gas pumping units is based on the use of combined characteristics of centrifugal superchargers, the processing of which by means of mathematical statistics allowed to obtain analytical expressions for the characteristics models. The calculation method can be implemented for forecasting the operation modes of the compressor station in conditions of both single-stage and multi-stage compression of gas. The source data for the calculation comprise the upstream and downstream pressure and temperature of gas, the volume of pumping and physical properties of the gas. In order to predict operating modes of compressor stations, the optimal distribution of load between workshops equipped with multi-type gas-pumping units is carried out provided that the energy consumption is reduced to compress the given volume of gas under known boundary conditions. The principle of constructing an optimality criterion for conditions of incomplete loading of the gas transmission system is shown.
 To illustrate the proposed method of optimizing the operation modes of compressor stations under incomplete loading, we give an example of the calculation of optimal operating modes of a hypothetical two-seater compressor station with various types of aggregates. The calculation is based on the construction of analytical mathematical models of their characteristics on the criterion of minimum capacity for gas compression at a given output and upstream and down stream pressures at the station.

OPTIMAL DISTRIBUTION OF PARALLEL WORKING EQUIPMENT WITH REGARD TO ENVIRONMENTAL TAXES UNDER UNDERSTANDING CONDITIONS

For a case where the compressor station, where the parallel-supplied gas-pumping units operate, has an excess capacity, the problem of optimal choice of the number of aggregates by a certain criterion arises. The prevailing criterion has two components. The first component is the cost of the fuel gas consumed by the compressor station. The second component is the ecological tax charged for the release of nitrogen oxides into the environment. To calculate the second component, an empirical model is synthesized in the form of a polynomial of a given degree which parameters and structure are determined using genetic algorithms. Such a model characterizes the dependence of the power of emissions of nitrogen oxides on the technological parameters that characterize the process of combustion of natural gas in the combustion chamber.
 In the generated problem of power emissions are calculated by the average values of technological parameters, which generates their fuzziness. Each parameter is characterized as the fuzzy value by a triangular membership function that is approximated by the Gaussian function.
 The formalized problem of choosing the optimal number of parallel operating units has in its composition the optimality criterion as fuzzy value and the limitations are determined by the given volume of pumped natural gas by the compressor station and the maximum allowable number of aggregates in each group of superchargers.
 The introduction of fuzziness generates a discrete nonlinear programming problem with linear constraints. For its solution, the method of boundaries and branches is used, on the basis of which algorithms and software are developed. The software is tested on the developed example, where the data used to determine the operation of the compressor station is used.