Abstract：
In long distance natural gas pipelines, the energy consumption of the natural gas compressor units account for
more than 95
%
, and their energy consumption has a great influence on natural gas enterprises. Domestically the industry
standard SY/T 6637-2012 is used to test and calculate the practical performance curve and the energy efficiency status. In
recent years, the standard has been used to calculate the polytropic efficiency of compressors and the unit efficiency. But the
calculated results weren’t consistent with the contributed data by foreign manufacturers. This inconsistence greatly influenced
the accuracy of gas pipeline optimization models and foreign advanced pipelines as the yardstick of energy management. By
the comparison and analysis of domestic and foreign standards, it was found that standard SY/T 6637-2012 is quite different
from the mainstream international standards in terms of variable index, enthalpy value and variable compression work
calculation. In view of the differences, the comparison and calculation were carried out, and the results were verified twice
with factory data and actual field data. The results show that: (1) In terms of enthalpy of gas, the error of calculating enthalpy
by the looking up the chart method is 6.55
%
, and the error of calculating method of BWRS, RKS and PR is 1.75
%
, 2.75
%
and
0.57
%
, respectively. (2) In the calculation of variable compression work, SY/T 6637-2012 didn’t consider the compressibility
of gas, modify the results, and add the variable compression work correction factor. (3) In the calculation of polytropic
efficiency, based on the calculation results of NIST software, the calculation deviations of SY/T 6637-2012, BWRS, RKS,
PR and CTO were 6.12
%
, 2.27
%
, 3.26
%
, 0.12
%
and 0.53
%
respectively. Based on the above analysis, SY/T 6637-2018 has
been released and implemented in March 2019. After one year application, the calculation method is consistent with the man
ufacturers' and foreign standards, and the calculation results are consistent. The test method is suitable for the actual situation
of domestic stations and yard energy consumption meters and installation location, and provides a reliable energy efficiency
calculation method for natural gas pipeline compressor units.
