DECOMPRESSION ENERGY RECOVERY DEVICE IN GAS PIPELINE

PROBLEM TO BE SOLVED: To make it possible to continue stable supply of gas while a secondary pressure of a governor is free from the influence of energy recovery, and to ensure setting of a temperature of the gas decompressed in an expansion turbine and returned to a secondary pipeline to be not less than a set temperature (0°C).SOLUTION: A decompression energy recovery device 1 comprises: an expansion turbine 10; a first gas line 11 connecting a primary pipeline P1 to an inlet of the expansion turbine 10; a second gas line 12 connecting an outlet of the expansion turbine 10 to a secondary pipeline P2; and a cold recovery heat exchanger portion 13 recovering cold of gas the temperature of which falls by energy recovery by the expansion turbine 10. A back pressure regulating valve 14 is provided downstream of the cold recovery heat exchanger portion 13 in the second gas line 12 for detecting the gas temperature and regulating a back pressure of the expansion turbine 10, and the gas temperature in the second gas line 12 is set to be not less than a set temperature (for example, 0°C) by regulating the back pressure by the back pressure regulating valve 14.SELECTED DRAWING: Figure 1 【課題】ガバナの二次圧がエネルギー回収の影響を受けること無く、安定したガス供給の継続を可能にする。膨張タービンで減圧して二次側パイプラインに戻すガスの温度を確実に設定温度（０℃以上）にする。【解決手段】減圧エネルギー回収装置１は、膨張タービン１０と、一次側パイプラインＰ１と膨張タービン１０の入口を繋ぐ第１ガスライン１１と、膨張タービン１０の出口と二次側パイプラインＰ２を繋ぐ第２ガスライン１２と、膨張タービン１０によるエネルギー回収によって温度低下したガスの冷熱を回収する冷熱回収用熱交換部１３とを備える。第２ガスライン１２における冷熱回収用熱交換部１３の下流側に、ガス温度を検出して膨張タービン１０の背圧を調整する背圧調整弁１４を設け、背圧調整弁１４による背圧調整によって第２ガスライン１２のガス温度を設定温度（例えば０℃）以上にする。【選択図】図１