Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
On the temperature correction in measuring natural gas volumes for household consumers
Submission Author:
Lidiane Mendonça Penna Francisco , RJ
Co-Authors:
Lidiane Mendonça Penna Francisco, Manoel Antônio da Fonseca Costa Filho
Presenter: Lidiane Mendonça Penna Francisco
doi://10.26678/ABCM.COBEM2023.COB2023-1689
Abstract
This study evaluates the technical and economic feasibility of implementing a temperature correction factor in all consumers’ measurers in a Brazilian metropolitan region. Residential consumers’ measurers of the natural gas network are volumetric, and diaphragm-type, so they are impacted by the ambient temperature fluctuations, but no correction is practiced. Natural gas distribution companies operate with volumes of gas expressed in standard-state conditions, complying with the regulations in force. The volumes of gas received in the Regulating Measuring Stations (RMSs) are corrected to the standard state, but for the small consumers, their gas volume mechanical meters do not permit to apply corrections. Consequently, there are differences between the corrected gas volumes received through the RMSs and the gas volumes delivered to the small consumers. The correction factors for gas volume measurements are often determined based on the annual average values of the atmospheric pressure and ambient temperature. Here, they were generated on an hourly base and a comparison was performed between using hourly or average values. Hourly ambient temperatures were obtained from the nearest weather station, as an hourly average within at least a ten-year period. Different physical relations for temperature correction were tested, searching for an equilibrium between accuracy and simplicity. Uncertainty analyses were performed to compare the measurement errors with the proposed corrections. The error parameters presented in the Regulation INMETRO 156/2022 were considered, and the measurement uncertainty evaluation followed the worldwide used guide ISO GUM 2008. This study assumes that the measurer is located indoors, so the occasional heating due to sunlight exposure is not considered. For the low-consumption homes, there is not a satisfactory cost-benefit relation in implementing the temperature correction, since the meters have a fixed rate for minimum consumption and the measurement error would be included. On the other hand, the economic feasibility of inserting temperature corrections was achieved for commercial natural gas consumers. The gas utilities in Brazil are equipped, almost in their entirety, with mechanical gas meters. An obvious and high-cost solution is to replace all mechanical gas meters with others that enable temperature correction. The proposed methodology for reducing the errors associated with using mechanical gas meters for domestic consumers is a viable alternative for faster and more effective measures.
Keywords
natural gas network, natural gas, Measurement uncertainty, volumetric gas meter
