When it comes to natural gas operation, it is imperative to talk about the problem of natural gas transportation issues. Natural gas transmission difference refers to the difference between the input trade measurement value and the output trade measurement value appearing in the transportation process of the fluid medium.
Natural gas transportation issues Transmission difference is an important indicator to determine the gas transmission cost of natural gas management enterprises. Whether the enterprise can effectively control the natural gas transmission difference will directly determine the operating cost of natural gas enterprises, which will affect the core competitiveness of the enterprise’s market.
- 1 Causes of natural gas transportation issues :
- 1.1 The difference between actual temperature pressure and standard temperature pressure produces a difference in transmission
In the Standard Reference Conditions for Natural Gas, the measurement conditions for natural gas should be 101.325kPa and 20°C, but in the actual measurement of natural gas, it is difficult to meet the reference standard conditions in both temperature and pressure. If the natural gas operator fails to install temperature and pressure compensation when measuring natural gas, it will inevitably lead to the deviation of the measurement results of natural gas from the actual value. Generally speaking, every 1 kPa increase in pressure in natural gas measurement conditions will cause natural gas to lose 1% of gas volume, and similarly, 1% of gas will be lost at 3°C.
When gas companies measure natural gas with a gas supply pressure of 2kPa or small merchants with a gas supply pressure of 2~3kPa, for cost reasons, the selection of metering instruments is a leather film meter without temperature difference compensation, which means that the gas company is bound to face 2%. Loss of loss. In addition, although the average temperature difference in each region is obvious throughout the year, the annual temperature difference in most parts of China is relatively obvious, so the loss caused by combining pressure factors and temperature factors has brought a huge burden to the cost of gas companies to a large extent and natural gas transportation issues.
- 1.2 Insufficient handover of natural gas transportation produces transmission difference
At this stage, the main conveying methods used by natural gas management enterprises when transporting natural gas are pipe transportation and trough transportation. Tank transportation is to canning the liquefied natural gas of the tank truck, but in the process of canning of liquefied natural gas, the actual loading and unloading volume is bound to be less than the procurement volume of the contract due to subjective or objective factors such as equipment, operation, etc.
Usually, when signing a contract with an upstream enterprise, the gas company will indicate that the settlement should be made within ±1% according to the purchase volume stipulated in the contract, which means that if the upstream enterprise consciously or unconsciously causes natural gas losses within a reasonable range during the loading and unloading process, even if the loss is relatively large and more natural gas transportation issues.
Small also causes gas companies to bear the corresponding loss of transmission. In terms of pipeline transmission, ultrasonic flowmeters are usually used to measure natural gas, but the relevant parameters of this type of flowmeter can be artificially controlled, so if upstream enterprises have subjective improper profit psychology, only need to set parameters that are beneficial to themselves will also lead to the transmission difference of gas companies. Loss and more natural gas transportation issues.
- 1.3 Pipeline network damage caused by poor transmission
The transmission difference caused by the destruction of the pipeline network is a common reason for the natural gas transmission difference in gas companies. Especially in recent years, it has frequently been exposed that the violent construction of construction units in China has led to the excavation of the natural gas pipeline network, which has caused very serious consequences.
For example, in 2019, a unit brutally excavated a natural gas pipeline under the condition of handling relevant procedures in Caidian District, Wuhan City, causing some civil, industrial and commercial users in Caidian District to cut off gas and fined 100,000 yuan by the law enforcement department. In 2018, when an excavator in Zunyi city was under construction at the intersection, it inadvertently dug the natural gas pipeline below, and the natural gas at the scene was sprayed out several meters high.
All of these will lead to the natural gas transmission problem of gas companies, and will not only cause losses to gas companies, but also pose a serious threat to the lives and property safety of the surrounding people. Of course, the transmission difference caused by the damage of the pipeline network not only comes from external damage, but also from internal damage caused by low construction quality and level of pipeline network and inadequate daily maintenance. All of these will lead to the emergence of natural gas transportation issues.
- 1.4 Transmission difference caused by downstream metering error
The downstream metering instrument is a common phenomenon which is important natural gas transportation issues. Usually, the dermal membrane surface will be accompanied by the aging of the dermal membrane with the increase of the service life, and the measurement value will gradually decrease. Especially if the replacement of the corchnocodum surface is not timely, the probability of measuring errors on the corchnocosa surface beyond the normal service life will be greatly increased. According to relevant statistics, this error can even reach 16%.
Moreover, when the people apply metering instruments, there are many phenomena that some people deliberately destroy instruments to achieve the purpose of stealing gas. There are even a few people who change natural gas pipelines in order to reduce gas metering, which not only leads to poor transmission in gas companies, but also brings serious safety hazards to the surrounding people.
- 2 Control measures of natural gas transmission
- 2.1 Implement the responsibility system for loss management
For gas companies, implementing the responsibility system for transmission management is an important means to strengthen the level of natural gas transmission management to lower the natural gas transportation issues.
Because for gas companies, transmission control is not a matter of one department, including gas pipeline construction, equipment maintenance, financial statistics and other departments must cooperate to achieve the transmission control goal more effectively.
Therefore, this requires that gas companies can formulate the responsibility system for loss management internally, clarify the responsibility of loss control of various departments and posts within the enterprise, and set the goal of loss control. Each department and position shall compile the transmission control plan according to the post responsibilities to reduce natural gas transportation issues.
At the same time, the gas company should also set up an incentive mechanism within the enterprise to praise the employees who can put forward rational and innovative suggestions for improving the management level of the enterprise’s transportation difference, mobilize the internal transport management activity of the gas company with material and spiritual rewards, and improve the level of transportation management.
- 2.2 Strengthen the supervision of tank transportation and pipeline transportation
In the process of tank transportation or pipeline transportation, objective natural gas transmission is inevitable, and what gas companies need to do is to minimize the transmission gap. In terms of tank transportation, gas companies can arrange tank transportation during the peak period of gas use, and directly introduce liquefied natural gas into the medium pressure pipe network after unloading it into gasified natural gas, which can reduce the first-class transmission difference. In terms of pipeline transportation and natural gas transportation issues.
Gas companies can follow up upstream enterprises irregularly, grasp the changes in parameters, and require the upstream to send the changes in parameter indicators regularly. In terms of poor management and transportation supervision, gas companies must take the initiative in order to achieve restrictions on upstream enterprises, so as to minimize the cost increase caused by natural gas transportation issues.
- 2.3 Strengthen the regulation of natural gas pipeline network
The most basic requirement for gas companies to avoid the natural gas transportation issues caused by the natural gas pipeline network is to strengthen the control of the construction, acceptance and other links of the natural gas pipeline network, and further optimize the design of the pipeline network. For projects with obvious construction hazards, it must be immediately stopped and rectified.
Only priority should be given to ensuring the construction of the natural gas pipeline network. Only by the quality of workmanship can we avoid the internal transmission risk of natural gas pipeline network. In terms of external transmission control cases, gas companies should set up systematic and perfect scheduling and inspection mechanisms. In this regard, gas companies can use SCADA systems to achieve the purpose of collecting and monitoring and controlling natural gas data, so that gas companies can respond to the leakage pipeline network in a timely manner, and Put forward a solution as soon as possible.
On the one hand, reduce the transmission gap as much as possible, and on the other hand, reduce the serious accidents that may be caused by natural gas spills. Protect the lives and property of the people around the pipeline network. However, the operating and application cost of SCADA system is relatively high for domestic gas companies at present, so it is more suitable for some gas companies with relatively strong financial strength.
Of course, in addition to relying on the system, the gas company should also carry out daily inspection of the core parts of the gas pipeline network, especially the implementation of the review responsibility system for cross-construction monitoring. Once there is a problem, the reviewer should also bear joint and several responsibilities, so as to strengthen the implementation of the function of the reviewer.
- 2.4 Increase the management of downstream metering instruments
To solve the problem of downstream metering instrument transmission, gas companies should actively build a more perfect metrology management system. On the one hand, it is to deepen the transformation and design of metering instruments and improve the service life of metering meters.
At the same time, meter reader should grasp the use of the skin film watch when reading, and replace the seriously aging skin film watch in time. On the other hand, it is necessary to post a seal prohibiting modification in the prominent position of the metering instrument, and prohibit users from carrying out instrument modification without permission. At the same time, it is necessary to strengthen the restrictions on users’ gas pipelines, and severely punish users who change gas pipelines privately to reduce natural gas transportation issues.
- 3 Conclusion
Although natural gas transmission is an inevitable additional cost for gas companies, for gas companies supported by modern management concepts, it is imperative to further improve their market core competitiveness and cost management level. Gas companies must set up corresponding control plans according to the causes of natural gas transmission differences, so as to better avoid the generation of transmission differences and lay a solid cost foundation for the development of gas companies.