Fuel Gas Consumption Research Articles

Modeling Gas Compressor Station Operation to Minimize Fuel Costs for Surge Zone Protection

Gas transportation through the pipeline network requires high pressure; otherwise, movement will be impossible. Due to friction with the walls of the pipes, the gas loses both speed and pressure. Therefore, it is necessary to increase the pressure in the main pipeline, which can extend for thousands of kilometers. For this purpose, compressor stations are located along the main network, facilitating the gas transport process by raising it to the required pressure. Compressor stations mainly consume the transported gas, with approximately 5% expended on gas compression. This article presents a study on the fuel cost for compressor stations, using mathematical models to optimize the operation of gas compressor units. The objective is to minimize gas consumption as a fuel and provide an optimization method with control over blower revolutions and valve installations to ensure safe transportation. Mathematical modeling of the described process detected the technically unjustified fuel gas consumption during the operation of gas compressor units at a specific compressor station under consideration. The paper proposes a method for minimizing costs, which can serve as the basis for providing recommendations to engineers-dispatchers. Compressor stations of the type under study lack measuring instruments for mass flow; therefore, the methods such as PID controllers, MPC, or neural networks are not applicable here.

Rapid Prediction of Hot-Air Temperature of Kalugin Top Combustion Hot Blast Stove by Means of Computational Fluid Dynamics Numerical Simulation

Based on the three-dimensional (3D) steady-state CFD numerical simulations conducted previously on an industrial Kalugin top combustion hot blast stove, a two-dimensional (2D) transient CFD numerical model for a single channel (hole) of a column of checker bricks in the regenerator of the same hot stove was established in the present work. The average mass flowrate and temperature of the flue gas flowing into the checker brick holes during the combustion period predicted by the 3D model were used as the inlet boundary conditions of the 2D model. Inside the hole of the checker bricks, processes of fluid flow and heat transfer of the flue gas during the combustion period and those of cold air during the hot-air-supply period were simulated using the 2D model for multiple operation cycles (combustion and hot-air-supply periods) of the hot stove, enabling rapid predictions of hot-air temperature under different operating conditions. The simulation results show that when the fuel gas flowrate and air consumption coefficient during the combustion period are controlled within the range of 80,000–100,000 Nm3/h and 1.02–1.28, respectively, a hot-air temperature in the range from 1273 °C to 1295 °C can be obtained during the hot-air-supply period. Applying this optimized operating condition to the industrial hot stove investigated in this study can achieve significant effects of reducing fuel gas flowrate by 8.6% and increasing hot-air temperature by 32 °C. In addition, a regression analysis on the numerical simulation results and the data measured from the industrial hot stove yields a roughly linear relationship between the dome temperature during the combustion period and the hot-air temperature during the hot-air-supply period, that is, the hot-air temperature would be increased by about 16 °C for every increment of 10 °C in the dome temperature, for instance. Therefore, the influences of the operating parameters on heat transfer characteristics in the regenerator and on hot-air temperature obtained in the present work provide a useful reference for guiding the hot stove operation optimization to achieve significant energy saving and emission reduction through facilitating more efficient combustion to minimize fuel gas consumption in steel plants.

Development of technology for cascade gas pressure reduction in long gas pipelines of gas distribution stations

The work developed and proposed for implementation an energy-saving technology of pipeline transportation of natural gas along long-distance branch pipelines connecting main gas pipelines and gas distribution stations. This technology consists in a step reduction of operating pressure in the gas pipeline branch with the help of linear reducing stations, with partial heating of gas due to heat exchange between the gas pipeline and the ground. The authors of the article present the results of practical approbation of the cascade gas pressure reduction technology in the operating off-take gas pipeline with the confirmed effect of reducing fuel gas consumption in the gas distribution station preheaters. The optimal parameters of gradual gas pressure reduction using linear reduction points were determined by calculation. Graphical dependencies, which determine the peculiarities of changes in temperature modes of pipeline gas transportation depending on the given pressure drop in linear pressure reduction stations for the conditions of pilot testing of the energy-saving method, have been obtained. A scheme of uniform location of linear pressure reduction stations with definition of the optimal pressure reduction mode is proposed.

Development and Research of a Regression Model for Assessing the Efficiency of Gas Compressor Units Operating Modes

This article addresses the issue of improving the energy efficiency of gas transportation equipment in main gas pipelines. To ensure the operation of gas compressor units (GCUs), transported gas is used, and as a result, compressor stations (CSs) consume a significant amount of fuel gas for their own needs. Therefore, increasing the length of main gas pipelines requires a high degree of fuel gas utilization efficiency. The article demonstrates the principles of using GCUs for gas transportation and the operating modes of GCUs. An analysis of methods for assessing the efficiency of GCU operation is conducted. To obtain a forecast of GCU operating modes, a mathematical model for evaluating the efficiency of GCU operating modes is proposed based on real statistical data of equipment operating mode parameters during industrial operation of GCUs in main gas pipelines. The regression model for GCU operating efficiency obtained from calculating the dependency of fuel gas consumption on pressure drop and transported gas flow inadequately reflected the GCU operating mode. To improve accuracy, a regression model for assessing the efficiency of GCU operating modes is developed based on quadratic dependencies on pressure drop, transported gas flow, and gas temperature at the inlet, satisfying the dispatcher control of GCU efficiency.

Feasibility Study of Harnessing Low Wind Speed Turbine as Hybrid Power Source for Offshore Platforms

In this study, the viability of harnessing wind energy for offshore oil and gas (O&G) platforms as a micro-grid solution in low wind speed regions to power O&G platforms is explored. However, wind, as a renewable energy, is known to be highly variable and is unable to provide standalone power reliably within a micro-grid solution due to the variation of the wind speed at hub height, which subsequently leads to a variation of the power outcome. Here, a hybrid power generation concept is developed in which one gas turbine generator (GTG) is replaced with a floating horizontal axis wind turbine (WT) system. By setting up this system, the reduction of the maintenance costs of the GTGs and the reduction of fuel gas consumption reduces carbon dioxide (CO2) emissions. In addition to this, the fuel gas savings in terms of the business side of such a solution provide a positive revenue impact. In this feasibility study, a technical framework is developed, followed by an economic framework. In the technical framework, wind assessments are performed to obtain the annual energy production for the selected field. Furthermore, an economic framework is established for both conventional and hybrid concepts in two scenarios: greenfield and brownfield, where the incremental net present value (NPV) and levelized cost of energy are calculated. The resultant difference in NPV for hybrid power generation compared to conventional power generation was found to be between 22% and 37%. The levelized cost of energy (LCOE) for WT is USD 165.52/MWh, which is 39% lower than for conventional, gas turbine-only operations. The LCOE for the hybrid approach is lower than for the conventional scenario by 22%. In conclusion, the hybrid micro-grid concept solution can harness wind energy from low wind regions with better economic benefits compared to conventional methods through the proper selection of the WT system, its floating substructure, and efficient micro-grid system for powering oil and gas platforms.

Optimal Operation of an Industrial Natural Gas Fired Natural Draft Heater

In this work, a custom dynamic mathematical model of an industrial vertical-cylindrical type natural gas fired natural draft heater is developed using gPROMS® ProcessBuilder®. The integrated model comprises sub-models for each of the distinct sections of the fired heater which are connected by mass and energy flows. The temperature profiles of the tubular coils and the process fluid, a heat transfer fluid (HTF) are modelled using the distributed parameter system (DPS) in the axial direction (1D). The flue gas temperature in each section is modelled using the lumped parameter approach. Published empirical methods and correlations are used for estimating some unknown model parameters. The resulting model is a system of partial differential-algebraic equations (PDAEs) and serves as a basis for conducting an optimisation study to aid decision-making and to identify the best operating conditions within the specified constraints that minimise the daily operational costs. Through process simulation studies, the model predictions are adjusted to closely approximate collected actual plant data. It is demonstrated through the optimisation study that significant reduction in fuel gas consumption can be achieved compared to the current operating consumption levels. The developed models can be extended for use by other hydrocarbon processing plant operators with slight modifications, by specifying geometric parameters, HTF thermophysical properties, fuel gas composition and properties, among others.

Effect of Combustible Fractions of a Sustainable Producer Gas Fuel on Spark Ignition Engine Combustion, Performance and Emission – An Experimental Analysis

This article addresses the effect of combustible components (hydrogen and methane) of a producer gas fuel on in-cylinder combustion, performance, and emissions of a modified spark ignition engine. Owing to the fluctuating tendency of an onsite gasifier produced producer gas composition, a dynamic behavior in engine combustion and performance was expected. Thus, the present study was motivated to investigate the magnitude of the engine response variables against the known fluctuating producer gas composition trend. Experiments were conducted using bottled fueled producer gas on 359 cm3 engine capacity at a compression ratio of 11:1 and 1500 rpm. Further, the engine was operated under naturally aspirated mode and close to stoichiometry. The analysis based on acquired in-cylinder data revealed that, the fractions of hydrogen and methane have a profound effect on combustion duration and specific fuel consumption. Further, the producer gas blends, leading to reduction in fuel gas consumption were identified. On emission front, carbon-monoxide and nitric oxide pollutants were predominant but within prescribed central pollution control board norms of India, especially at full load engine condition and hydrogen enriched blend respectively.

Pinch Analysis Application for Fouled Crude Distillation and Condensate Fractionation Units of a Refinery

Preheat trains of each Crude Distillation Unit (CDU) and Condensate Fractionation Unit (CFU) of a refinery in Malaysia were experiencing severe fouling. This led to lower heat recoveries of the pump arounds and higher fuel gas consumptions in the furnace and the reboiler of the units. Consequently, potential energy recovery options and possible fouling mitigation strategies needed to be explored. Adding few new heat exchangers to increase heat recovery in the below pinch region has been found to potentially reduce the fuel gas consumption by about 7 – 10 %, depending on crude scenarios. Further analysis of the preheat trains showed that heat exchangers at the higher temperature end of the network (above Pinch region) experiencing more severe fouling than the others. These heat exchangers were then recommended to be cleaned more frequently or to be modified to become less susceptible to fouling. This approach of adding new heat exchangers in the below pinch region and doing more frequent cleaning in the above pinch region could be seen as a practical application of the Plus/Minus principle of Pinch Analysis. More detailed process engineering calculations needed in the next phase of this project for actual implementations and detailed economic evaluation.

Development of the system of energy and resource saving during the operation of the gas pumping unit

The object of research is the fuel gas system of a gas turbine engine. The study of the use of secondary energy resources of the gas-pumping unit at the compressor station of the main pipeline has been carried out. The work of a gas turbine engine, including the work of the fuel gas system, is considered. The main drawback of the fuel gas system is revealed – ineffective use of excess gas pressure. An informational analysis of the options that eliminate the identified drawback is carried out. It is shown that in order to eliminate the disadvantage, it is advisable to use a turbo-expander at the compressor station to utilize the excess pressure of the fuel gas. It is also shown that the operation of a fuel gas turboexpander to drive an additional air compressor as part of a gas turbine engine is impractical. An expander-generator set with the generation of additional electricity at the compressor station is recommended for use. Modeling the operation of the utilization system made it possible to recommend constructive proposals for its improvement. A schematic diagram of a system for the complex utilization of excess pressure of fuel gas and heat of combustion products from the operation of a gas turbine engine is proposed. The system of complex utilization includes parts-generator unit, heat exchanger for cooling process gas and heat exchanger for firing gas. Regenerative heating of fuel gas up to 250 °С reduces energy consumption for heating it up to the ignition temperature. A model of a robot installation of the type GPU 16/56-1.44 (Ukraine) is carried out. It is determined that when a component engine of the J-59 (Ukraine) type with a shaft power of 16 MW operates, it is possible to additionally receive 102 kW of electricity and save 64 m3/h of fuel gas. It is revealed that the subcooling of the process gas does not play a significant role in reducing energy consumption during its transportation. It is recommended to use the process gas to heat the cold fuel gas stream downstream of the turboexpander to positive temperatures. The integrated utilization system is not a simple connection of an expander-generator set and two heat exchangers along the flow of the fuel gas. As a result of its operation, a significant reduction in the consumption of fuel gas and electricity is achieved. The disadvantages that hinder the implementation of a comprehensive disposal system are identified. This is the use of equipment for generating electricity at a compressor station. It is uncharacteristic for the operation of the station and requires additional qualifications in service. It is also required that the characteristics of industrial expander-generator sets correspond to the fuel gas consumption of a gas turbine engine.

Heat transfer analysis of submerged combustion vaporizer under subcritical pressure and comparison with supercritical pressure

The boiling heat transfer under subcritical pressure is used in the vaporization process of submerged combustion vaporizer (SCV). In this paper, the SCV heat transfer calculation model is established by using the method of enthalpy segmentation. Based on this model, the temperature field, heat transfer characteristics and influencing factors of SCV under subcritical pressure are analyzed. The results show that the heat transfer inside tube under subcritical pressure is mainly single-phase convective heat transfer, the boiling heat transfer takes up a small proportion of tube length, but the enhancement degree is higher. In terms of the influence of operating load, 0.3 times standard load is the load threshold value of the SCV in calculation, on both sides of the threshold value, the flow boiling heat transfer coefficient shows an opposite correlation with the operating load. Due to the dominant role of nuclear boiling, the average heat transfer coefficient under subcritical pressure is higher than that under supercritical pressure, but the corresponding fuel gas consumption increase as well. Therefore, the SCV units operating under subcritical conditions can get better heat transfer performance by increasing the pressure to near critical level.

Effect of air combustion preheater on furnace efficiency by using refinery simulator

One of the basic crude oil refining steps is the heat up to high temperature about 3700 C, which is done in the furnace. The balance between fuel and air required to combustion provide an economical and efficient heating.
 In this research operating data of heating up the furnace are collected by using an interactive simulator of Drilling System Company (ORTIS) which gives a flexibility of operation cannot be obtained in real furnace, these data are related to find the operation paths under different control system of manual, automatic and working automatic without pre-heating are used .
 Using of combustion air preheater, by exchanging heat with the flue gases, leading to increase furnace heating efficiency from 85% to 93% also the fuel supplied to the burners is more less than working without preheater.
 As the simulator used in this research very closed to real operating system of furnace which cover all the variables of furnace inside temperatures, excess air analyzer, and fuel gas control and inside pressure control.
 The using of interactive simulator is very useful in stating the right operating conditions. The use of pre-heating of combustion air is best economical method to reach heating the crude oil to the required temperature with minimum fuel gas consumption, which directly affects the efficiencies of the furnace in each case.

Determination of the efficiency of the gas-pumping unit of the compressor station according to the data of its operation

For the first time, the article analyzes the efficiency of the booster compressor station's TCU based on the data of its operation based on the gas-dynamic processes that take place in the gas compressor impeller. The limiting modes and the possibility of work of a multistage booster compressor station of a gas field at a late stage of its operation at low reservoir pressures have been determined, which makes it possible to carry out a set of measures for the choice of equipment and modes of work TCU. The implementation of the measures makes it possible to minimize the negative impact work of TCU on the environment and to optimize the material and monetary costs of natural gas transportation. On the basis of the presented algorithm, a method has been developed for calculating the efficiency of the gas-pumping equipment of the second stage of a compressor station, which pumps natural gas from a group of gas fields at a late stage of their operation into the main gas pipeline. As an approbation of the proposed methodology, the dispatching data of the second stage of the compressor station in two versions: operation with one and with two gas compressor units are considered. The calculation results are presented in tables. It is concluded that, regardless of the fact that the inlet pressure is low, and the flow path of the gas compressor is seven-stage, the work of friction forces and the work of thermal forces in the impeller of the gas compressor are relatively small relative to the value of adiabatic work, which is directly used to compress natural gas. The design and geometrical dimensions, the number of blades for each stage of the gas compressor, based on the operating conditions, are well chosen. The indicator efficiency of the gas compressor is 71%. The fuel gas consumption of the blower drive for pumping 1000 m3 is 17 m3. During the operation of a compressor station with two gas compressor units, the productivity of one compressor decreased to 75 thousand m3 / hour with an average productivity of the compressor station of 150 thousand m3 / hour. In this case, the gas compression ratio increased to ε = 3.2, and the polytropic index decreased from 1.44 to 1.34. The work of the frictional forces and the work of thermal forces are even smaller in comparison with the adiabatic work, and the indicator efficiency of the gas compressor increased to 85%. Therefore, the operation of a compressor station with two TCU is more efficient than with one. However, the fuel gas consumption of the blower drive for pumping 1000 m3 when the compressor station operates with two TCU is 23 m3, and the effective power on the blower shaft is 3750 kW, which is much less than the nominal value. This means that efficient operation of two blowers in parallel is impossible due to insufficient productivity of the natural gas field. This increases the consumption of fuel gas, which leads to an increase in emissions of carbon dioxide into the atmosphere. Therefore, for the effective operation of the compressor station, it is necessary to reconstruct the first stage in order to increase its productivity, to increase the working pressure at the inlet to the compressor of the second stage of the booster compressor station

Optimization of Thermal Parameters of the Coke Oven Battery by Modified Methodology of Temperature Measurement in Heating Flues as the Management Tool in the Cokemaking Industry

Coke production is still of great economic importance due to its crucial role in the steel production process. The reliability of the operation of coke oven batteries depends on the maintenance of good technical condition of their ceramic massif, which in turn requires ensuring proper operation of the heating system and maintaining temperature stability in the heating flues. Regularly performed temperature measurements in heating flues due to the size of the battery and the dynamics of accompanying processes do not reflect the actual thermal state of the object at a given time. Corrections commonly introduced to the results of temperature measurements in heating flues, taking into account so-called reversion, significantly improve the accuracy of the obtained measurement results. However, still the interpretation of the results of temperature measurements in the coke oven battery heating flues does not take into account its changes during the coking cycle, even though they reach up to 60 K. The article discusses the usability of the introduction of a new, additional correction to the temperature measured in the heating flues enabling a more precise assessment of the current thermal state of the coke oven battery. The use of the method will allow for reduction of the fuel gas consumption and limitation of emissions resulting from its combustion and can be used as an effective tool for decision making.

Influence of neodymium magnet field on fuel gas metering with diaphragm gas meters

The article deals with the problem of illegal fuel gas consumption among individual consumers in households, especially with regard to gas theft using neodymium magnets attached to diaphragm gas meters. First, the author presents a historical outline of the use of neodymium magnets for the purpose of illegal consumption of fuel gas. The current legal status regarding the requirements for gas meters resistance to tampering and the activities of the Oil and Gas Institute – National Research Institute (INiG – PIB) and Distribution System Operators aimed at eliminating the possibility of illegal gas consumption with the use of neodymium magnets were discussed. Currently possible methods of confirming gas theft using gas meters exposed to the magnetic field of neodymium magnets were presented. Next, the methods of performing at the INiG – PIB laboratory expert examinations of gas meters suspected to be used for illegal gas consumption after their removal from the distribution network were described, and the criteria for assessing these gas meters were given. Based on the expert examinations of gas meters carried out at the Laboratory of Flow Metrology INiG – PIB in the years 2006–2020, a summary of the share of gas meters tampered with the use of neodymium magnets and gas meters with an increased remanence level was presented in relation to performed in a given year expert examinations of gas meters suspected to be used for illegal gas consumption. The methods of counteracting the theft of fuel gas with diaphragm gas meters tampered with the use of neodymium magnets were shown. It has been proved that at present the EC type examination certificate (MID Directive) and the certificate of compliance with the requirements of EN 1359 or OIML R 137-1 & 2 specification do not confirm gas meters resistance to gas theft involving the use of a strong magnetic field. Requirements for new diaphragm gas meters in terms of their resistance to neodymium magnets were presented, and updated criteria for the evaluation of the test results of gas meters exposed to these magnets were given. Finally, a conclusion was proposed regarding the necessity to include provisions on the resistance of diaphragm gas meters to magnetic field in the relevant normative documents for gas meters in order to provide a systemic safeguard for the parties to fuel gas supply contracts.

Aromatics oxidation in the furnace of sulfur recovery units: Model development and optimization

The frequent changes in the composition of acid gas feed to the Claus process cause flame instability and lead to the incomplete destruction of aromatic contaminants in feed that are benzene, toluene, ethylbenzene, and xylenes (BTEX). These aromatics cause frequent catalyst deactivation. The current literature lacks a reliable global kinetic model that can ease the computational burden of optimizing the process parameters to enhance flame stability and support BTEX destruction. In this paper, a kinetic model for BTEX oxidation is developed for the first time using a detailed reaction mechanism and is validated using plant data. The model is used to evaluate the effects of inlet air preheating, methane co-firing, and oxygen enrichment on BTEX destruction and furnace temperature. The simulation results ascertain that a favorable increase in the furnace temperature can be achieved with appropriate feed parameters such as feed temperature and O2 concentration to decrease BTEX emission from the furnace below 6 ppm. The model is used to conduct an optimization study that successfully demonstrates its capability to predict optimized inlet parameters for effective BTEX destruction, a high sulfur recovery efficiency, a low emission of CO and SO2, and a reduced fuel gas consumption in the Claus process plants.

Study of the operation of a 110 MW combined-cycle power unit at minimum loads when operating on the wholesale electricity market

Currently, all generating equipment with a capacity of more than 25 MW operates in the wholesale electricity market. The operation of combined cycle gas turbines is complicated by the implementation of daily load schedules. A distinctive feature of the operation of combined-cycle units is the presence of a gas and steam turbine in the cycle. In this paper, the variable operating modes of a combined cycle plant are considered. The minimum effective load of a gas and steam turbine is determined. An example of the real operation of a steam turbine that is included in a combined cycle plant 110 MW power unit at an operating combined heat and power is shown. The optimal minimum load of a combined cycle gas turbine unit has been determined. As a result of the research, the values of high and low pressure steam flow rates, fuel gas consumption, steam and gas turbine power were obtained. Based on the research results, the optimal minimum load of a combined cycle gas turbine unit was found - 40 MW. This load allows the main and auxiliary equipment to work without compromising reliability.

Experimental and simulation investigation of pulsed heat pipes in gas compressors

In natural gas pressure boosting stations, air coolers are used to reduce the gas temperature. Pressure drop as an essential factor in determining the energy performance of any pressure boosting station has a significant impact on the overall performance of the gas transmission. In this paper, a laboratory pilot is designed to investigate the effect of pressure drop reduction on the use of heating pipes at the air coolers. In addition, as a case for a gas pressure boosting station, its impact over energy performance index and pressure drop parameter has been calculated through simulating. The results show, implemented PHP tubes in an air cooler, lead to reduce tube length and improve pressure drop, 44.59, 40.4, 36.78, 23.34% in four gas flow rate. Also, this approach decreased fuel gas consumption more than 1,114,000 Sm3 and 3,889,440 kWh electrical consumption in air coolers, annually. Beside, investigation of energy performance indicators reveals that this approach might improve the total energy performance, thermal performance and electrical energy performance indices up to 3, 2.3 and 79%, respectively.

Heat Integration of a Boiler and Its Corresponding Environmental Study in an Oleochemical Production Plant: An Industry Case Study in Malaysia

The growing demands for oleochemical products are expected to reach approximately RM 157.59 billion by 2026 due to an increased drive from the food and beverages, chemicals, and pharmaceutical industries. However, this will lead to an increase in energy consumption and subsequent flue gas emission. Proper utilization of waste gas recovery systems is thus a major research area, focusing on reducing fuel consumption and emissions of greenhouse gases without affecting process performance. In this paper, a palm oil-based oleochemical plant is studied. The fuel consumption and emission of flue gas from a thermal oil boiler were measured and the feasibility of implementation of a waste heat recovery system and its environmental impact study. The results show that the implementation of such a system can reduce natural fuel gas consumption by 17.29% and approximately 149.29 t per annum of carbon dioxide gas (CO2). Moreover, the concentration of CO2 released into highly-populated communities is estimated through a Gaussian Plume Model at different wind speed conditions. The preliminary results show that the CO2 concentration at two locations—an apartment and a local school located within 1.5 km of the plant—is well below the concentration limit of 1.938 g/m3 recommended by the Wisconsin Department of Health and Services.

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