ON THE ANALYSİS OF OPERATİNG PRACTİCES OF LİQUEFİED GAS PİPELİNES
Authors: Togrul Karimov Togrul Karimov 
Published: March 2022

The commissioning of high-productivity fields in the Caspian Sea over the years since the signing of the Treaty of the Century serves to accelerate the development of our country by demonstrating to the world the growing energy potential of Azerbaijan. The measures taken after the contract years of our country include the commissioning of the Baku-Tbilisi-Ceyhan, Baku-Tbilisi-Erzurum oil and gas pipelines, the development of the Shah-deniz gas, Azeri-Chirag oil and Umid gas condensate fields, has become an oil and gas exporter to a number of countries based on the implementation of the TANAP and TAP projects within the Southern Gas Corridor project. The effective development of large-scale gas and condensate fields discovered in the deep waters of the Caspian Sea, which has been declared the 21st century in the world and entered into with major gas contracts, depends on the organization of safe and reliable operation of gas transportation systems. The main criteria for technical decisions made in connection with the preparation and transportation of gas during the development of gas condensate fields are the requirements for the operation of gas pipelines. It is also important to choose the right diameter of the pipeline. Larger diameters will incur additional costs and corrosion erosion in the pipeline, while smaller ones will not only limit the yield of production wells, but also increase pressure losses. On the other hand, if the transport distance of condensable gases is limited under certain wellhead pressures, the pipeline will be filled with condensate and gas transportation will be difficult. Therefore, process equipment and pipelines should be selected in such a way that it is possible to produce well products at all stages of field development. Azerbaijan's proven gas reserves are not the limit of 2.6 trillion m3. Many fields are still being assessed, and some fields are being explored, which is expected to increase resources. Therefore, the diversification of routes, the reliability of the complex for the transportation and storage of hydrocarbon resources is one of the main conditions for ensuring energy security. Accidents in the collection and transportation system as a result of complications arising from the physicochemical and rheological properties of hydrocarbons during transportation and storage, along with the loss of valuable raw materials, also damage the ecological condition of the environment. Elimination of the consequences of accidents and damage to the environment, as well as the restoration of the normal operation of the transport system requires additional financial resources. Thus, both hydrocarbon losses occur and the environment is polluted, as well as additional funding The cost increases due to the expenditure of funds. Analysis shows that in many cases, the difficulties and complexities that occur during the collection, transportation and storage of hydrocarbons are due to their multi-component and multi-phase, as well as structural structure.
The sources of technological gas losses are indicated, and it was noted that the losses are due to the non-compliance of the equipment used in gas transportation processes and the technologies used in these systems with modern requirements. Due to the unsatisfactory operation of these instruments and equipment, a large amount of the liquid phase remains in the gas and is transferred together with the gas to the transport system. During transportation, as a result of the thermobaric effect of the environment, the thermodynamic parameters of the gas change, and the process of condensation of hydrocarbon condensate and water vapor in a liquid, i.e., phase transitions, leads to a change in the density and composition of the gas. This, in turn, leads to a difference between the amount of gas delivered and received. The value of gas losses in transport systems due to phase transitions varies depending on the season. On the other hand, retrograde phenomena such as condensation and evaporation can also occur under certain thermobaric conditions. That is, evaporation can occur with an increase in pressure, and condensation - with a decrease in pressure. At the same time, the lower temperature of the gas enriches it with water vapor and heavy hydrocarbons. Given that the main condition for the condensation of liquid vapor in a gas depends on the degree of saturation of the gas with vapor, and changes in pressure and temperature during transportation are of great importance. Since the phase transitions due to pressure and temperature changes during transportation were observed with hydrocarbon losses, gas losses were estimated based on the physicochemical analysis of gas samples taken from high and low pressure gas pipelines to assess these losses. According to operational data, the technological state of gas pipelines was studied. Timely and accurate assessment of the technological state of gas pipelines for reliable and safe operation is also very useful in terms of reducing hydrocarbon losses. The analysis showed that, in addition to monitoring the transport parameters, the effectiveness of quality and operational control over the operation of the gas pipeline can be improved on the basis of constant monitoring of the quality and composition of the gas. In other words, the properties of the gas component change along the pipeline can be used as a source of information. The discovery of a significant difference between the components of the gas at the beginning and end of the pipeline confirms the above. During the transportation of gases through the pipeline, the release of the liquid phase in the pipelines, such as water and condensate, due to incomplete completion of their preparation stage, complicates the operational process. Therefore, the transportation of gases and their various mixtures requires a proper assessment of the internal condition of the pipelines and the prevention of additional energy costs. Taking into account structural changes during the transportation of gases, including their various mixtures, the application of new methods for monitoring the operation of a gas pipeline, based on a change in the composition of the gas component, is considered for diagnosing the technological state of the gas pipeline. In order to prevent local erosion-corrosion spills in pipelines during gas transportation, in the first place, the separation of mixtures in the form of separate phases during transportation should not be allowed. According to the available data, the correlation between the corrosion rate in gas pipelines and the motion mode of the mixture in pipelines is very strong. In this regard, the removal of the liquid phase from the gas flow from inside the gas pipelines is accompanied by an increase in the efficiency of the system due to the protection of pipelines and auxiliary structures from corrosion.
Keywords: separation, gas, pipeline, condensate, temperature, liquid additives, atmosphere.