PSI - Issue 59

Ya. Grudz et al. / Procedia Structural Integrity 59 (2024) 750–756

751

2

Ya. Grudz et al. / Structural Integrity Procedia 00 (2019) 000 – 000

From the point of view of the service process, the city's gas supply system is an extremely complex technical network with a branched and ringed gas transportation network, which consists of various types of gas pipelines as its elements, gas distribution stations and gas distribution points connected by complex functional dependencies. Therefore, the process of preventive maintenance of such a network should be considered as a multifactor optimization task in the conditions of a centralized service system. The process of managing the technical condition of objects in the area of centralized maintenance of the gas supply system, which includes independent and permanently operating objects, should be considered. Independent subsystems mean independence from their failures - an assumption that is basic, as a rule, when considering the reliability of pipeline systems from the position of a systems approach. Assessment of the energy efficiency of gas transportation for the purpose of a suitable technical or technological decision to ensure the reliability of gas supply is considered by Grudz (2012) and Grudz et. al. (2012). As you know, to assess the energy efficiency of a technical system in which energy and work are transformed, the concept of the coefficient of useful activity of the system, which is determined by the ratio of the useful work performed to the total energy consumption, is generally accepted. The purpose of the research is to assess the energy efficiency of gas networks and their elements and establish factors that have an impact on reducing energy costs for gas transportation. 2. Research results and their discussion The overall value of the efficiency coefficient for the entire technical system can be determined by utilizing the values of all constituent elements of the efficiency coefficient in accordance with the established principle Based on the classical definition of the efficiency factor, to calculate its value in the conditions of the gas transportation system and the gas network as its element, it is necessary to establish the amount of useful work and the total energy consumption. The work performed to move a given amount of gas over a certain distance at predetermined values of pressures and temperatures can be considered useful. If the transported amount of gas is attributed to a unit of time, then the useful work will be considered as power consumption, which for the flow of the medium in the pipes is expressed by dependence (Grudz et. al. (2014a) N Q g H k      , (2) where Q - consumption of the environment by density  ; H - head losses associated with the work of resistance forces to ensure the given flow rate. It is obvious that for a gas pipeline that transports a compressed medium, the pressure loss should be replaced by a difference in operating pressures at the beginning and at the end of the gas pipeline n 1 2 1 ....      n i (1)

P P

T T

( z P P  

)

N Q 







st

sr

(3)

.

k

st

sr

p

k

sr

st

The volume flow rate of the gas pipeline under operating conditions is a variable value along the length of the route even with the stationary nature of gas movement. Therefore

P P

T T

M Q





Q

z R T Q   

z

 









st

sr

st

st

(4)

sr

sr

sr

st

P



sr

st

sr

sr