## Blog Archives

## Transportation, storage, pipelines

## THE LIQUEFIED HYDROCARBONS EVAPORATION MATHEMATICAL MODELING AT THE REZERVOIR THERMAL INSULATION DAMAGE

The paper deals with insulated tanks of liquefied gas operation under normal conditions and in violation of the thermal insulation.

It is shown that the most widely used for double-walled tanks as an insulating material the pearlite filling is used. Over time, the operation undergoes pearlite precipitation, which leads to distortion of insulating performance of the entire system. The resulting voids increase the heat leakage to the tank and accelerates the evaporation process, which inevitably forces the refrigeration compressors working to work with overdrive. The greater the void area formed by precipitation in the heat insulation, the higher the probability of an emergency.

In order to develop a mathematical model of the thermal contact with the vessel environment is made up of the heat transfer interconnected system of equations through the bottom, a side wall, roof and mass transfer equation. The approximation methods for solving differential equations and models built on these thermal processes isothermal storage are analyzed.

A mathematical model to estimate the heat transfer coefficient at draft pearlite by up to 38% of the height of the inner tank is created. The value of the additional heat input, depending on the climatic conditions of the region is established. The analytical ratio to determine the additional evaporation from the surface of the liquid gas in the tank on the depth of precipitated thermal insulation is developed. A comparison with the standard indicators is done.

## THE PIPELINE GAS TURBINE SET RELIABILITY PARAMETERS ESTIMATION

The article deals with reliability assessment of gas pumping units of the gas pumping system of Russia by the GTC-10 as example. The park structure of gas pumping unit types is presented. It is shown that the aggregates of this type are of the very large group of gas pumping equipment.

It has been established that a significant part of gas pumping units is worn-out. About 8% of GPA worked more than 100 thousand hours, 45% – 50÷100 thousand hours. By the example of one of the subsidiaries of PJSC “Gazprom” the analysis of quantitative indicators MTBF GTC-10 are done. The empirical reliability function, the density of developments units to failure after major repairs distribution, the failure rate are built.

According to the renovated GPA parameter “the failures distribution density” the kind of the distribution law is determined. It is shown that it is the law of the Weibull distribution.

Analysis of statistical data on the operation of gas pumping units showed that the entire life cycle of work can be divided into three characteristic regions – running, normal operation, the period of wear and aging. For each time period, the Weibull distribution parameters are defined and presented in tabular form.

In the end of the article the conclusions about an increased failure rate of GPA at the equipment running and aging steps are done. The identification of patterns is recommended to be taken into account when planning repairs, vibration surveys and findings of gas pumping units in reserve.

## ENERGY SAVING TECHNOLOGY SELECTION MODE WORK COMPRESSOR STATIONS IN REPAIR GAS PIPELINE

One of the priority directions of scientific and technical PJSC “Gazprom” is to improve the technology gas trunkline by finding and developing new ways to get added value of natural gas saving.

To maintain the efficiency of gas mains to carry out spot repairs on the results of in-line inspection. In recent years, in PJSC “Gazprom” a significant rate being diagnostics and repair of trunk pipelines.

During repair work on gas pipelines is a very urgent problem of rational use of the gas pipeline section to be disconnected. In general, according to official statistics, emissions of road works 75% of total emissions by the PJSC “Gazprom”.

Development of gas to gas-compressor units are always justified in referring to providing pumping large volumes of gas availability possible the widespread use of this method without additional variable operating costs. The lower the pressure at the outlet the compressor station, the more will reduce the gas pressure shut down for repair of the gas pipeline and therefore achieve the greatest depth of the development of gaz. It should take into account the operating conditions of an opportunity of stable work of gas pumping units in unsteady regime that is in the fall of the inlet pressure to the minimum allowable value of creating the lowest possible outlet pressure gas compressor units.

In this, based on experimental data solved the complex problem of the development of gas and two heterogeneous working “in parallel” aggregates and reduce the emission of methane into the atmosphere.

## MEASURES TO IMPROVE ENERGY EFFICIENCY TECHNOLOGICAL PROCESS LINEAR INDUSTRIELLE SENDING STASJONER (LPDS)

Currently relevant is the question of enhancing the efficiency of the main oil pipelines.

The share of energy costs in the pipeline transport of oil is 30% and this figure continues to grow. This growth is caused by the increase in oil production and a correspondingly increased volumes. The dependence of energy consumption in freight rail turnover is a power-law dependence. Therefore, with an increase of turnover of oil specific energy consumption is not reduced, but increases in proportion to the turnover to the extent of 1.75. For this reason, it is necessary to carry out activities for energy efficiency and energy savings.

The primary power consumer in the pipeline transport are pumping units at OPS and LPDS. When monitoring operational characteristics of pump units is possible, energy savings of 9 to 21 % of the costs of energy for oil transportation: the upper point is due to structural changes in pumps, the lower only through the maintenance of the units in their actual condition.

Comprehensive monitoring of the technical state of each pump unit one step closer to the technology improvement of trunk pipeline transportation of oil.

The article describes the technical energy saving measures to improve energy efficiency of technological processes LPDS, developed and justified measures to improve the energy efficiency of pumping units.

## ORDER STATISTICS IN HEAT SYSTEMS

In the article the analytical solutions for the increasing of accuracy of technological flows discharge by using stationary flowmeters are proposed. The calculations are realized for determination of heat system water discharge.

The data base analysis by Kendal coefficient using is done. The result has shown the high level of statistical significance of correlation between the measurements of stationary and master flowmeters. For such the data base the measurements ranking methods may be realized.

This method realization is proposed in two variations. The first one is the searching of interrelation between the measurements of stationary and master flowmeters. In the article is shown, that the mathematical model based on independently ranked data, has higher accuracy than data base straight calculations. But this model can be recommended only for data base under normal distribution.

Otherwise the next variant is recommended – as nonparametric method with the principle of statistical series numerating. Every value has the own number. So the statistical series become ranking, and the every value number becomes its rank.

The both methods were realized for creating the model on the data base of heat system. The model describes the interrelation between the measurements of stationary and master flowmeters.

In the article is shown, that the realization of this methods increased the accuracy of discharge determination to 0,995.