一、引言目前,管输天然气的贸易结算大都采用换算到标准状态(1个标准大气压、20℃)下的标况体积流量。通常情况下,当气体压力接近于标准大气压时,可以近似地作为理想气体处理,理想气体遵循状态方程PV=n RT(式中:P——气体的绝对压力;V——气体的体积;n——物质的量;R——普通气体常数;T——气体的绝对温度)。标况下体积流量V0为V0=V1×P1P0×T0T1 I. INTRODUCTION At present, the trade settlement of pipelines for natural gas mostly adopts the standard volume flow rate converted to the standard state (1 standard atmospheric pressure, 20 ℃). Normally, when the gas pressure is close to normal atmospheric pressure, it can be approximated as the ideal gas. The ideal gas follows the equation of state PV = n RT (where P - the absolute pressure of the gas; V - the volume of the gas; n - amount of substance; R - ordinary gas constant; T - absolute temperature of the gas). Under the condition of the volume flow V0 is V0 = V1 × P1P0 × T0T1