Natural Gas Transportation requires Natural Gas to be in its Liquid state, liquefying Natural Gas requires decreasing temperature to a very low level. This requires severe temperature and pressure conditions. This pap...Natural Gas Transportation requires Natural Gas to be in its Liquid state, liquefying Natural Gas requires decreasing temperature to a very low level. This requires severe temperature and pressure conditions. This paper will discuss a risk assessment study on a Node in the plant of Natural Gas, which is the propane heat exchanging unit, which decreases the temperature of the flow gradually at the beginning to remove heavy liquids. Risk assessment study is applied using three methods, HAZOP, DMRA and LOPA.展开更多
This paper proposes a differential mode measurement and control system(DMCS)for differential MEMS resonant accelerometer(DMRA),which operates the differential resonators of the DMRA at different vibration modes.Unlike...This paper proposes a differential mode measurement and control system(DMCS)for differential MEMS resonant accelerometer(DMRA),which operates the differential resonators of the DMRA at different vibration modes.Unlike traditional DMRA,the first resonator of the differential resonator operates in the first-order mode(R1M1),and the second resonator operates in the second-order mode(R2M2).Within the measurement range of DMRA,the frequencies of the two resonators will not cross,so there will be no mutual interference.This ensures the structural symmetry of the DMRA while avoiding the measurement dead zone phenomenon caused by the coupling of the differential vibration beam at similar resonant frequencies.The structural symmetry of the differential resonator ensures good temperature consistency of the differential vibration beam,and the consistency of the temperature frequency coefficient matches well,which enables the differential resonator to strongly suppress the temperatureinduced common-mode effects.During the temperature cycling process between-20℃ and 80℃,the equivalent acceleration drift of R1M1 and R2M2 were 341.6 mg and 414.6 mg,respectively.After using the differential temperature compensation algorithm,the equivalent acceleration drift was reduced to 1.19 mg.The minimum Allan variance measured statically at room temperature decreased from 1.42μg@0.85 s for R1M1 and 1.52μg@0.85 s for R2M2 to 0.23μg@7.15 s,indicating a significant improvement in the long-term stability of DMRA.In addition,the differential measuring method also eliminated common mode ambient noise in low frequency range,ultimately achieving a noise level of 220 ng=ffiffiffiffiffi Hz p@(0.2–0.8 Hz)for a prototype device with a measurement range exceeding±5 g.展开更多
文摘Natural Gas Transportation requires Natural Gas to be in its Liquid state, liquefying Natural Gas requires decreasing temperature to a very low level. This requires severe temperature and pressure conditions. This paper will discuss a risk assessment study on a Node in the plant of Natural Gas, which is the propane heat exchanging unit, which decreases the temperature of the flow gradually at the beginning to remove heavy liquids. Risk assessment study is applied using three methods, HAZOP, DMRA and LOPA.
基金supported in part by the National Key Research and Development Program of China under Grant 2022YFB3207301Shandong Provincial Natural Science Foundation under Grant No.ZR2024ZD08.
文摘This paper proposes a differential mode measurement and control system(DMCS)for differential MEMS resonant accelerometer(DMRA),which operates the differential resonators of the DMRA at different vibration modes.Unlike traditional DMRA,the first resonator of the differential resonator operates in the first-order mode(R1M1),and the second resonator operates in the second-order mode(R2M2).Within the measurement range of DMRA,the frequencies of the two resonators will not cross,so there will be no mutual interference.This ensures the structural symmetry of the DMRA while avoiding the measurement dead zone phenomenon caused by the coupling of the differential vibration beam at similar resonant frequencies.The structural symmetry of the differential resonator ensures good temperature consistency of the differential vibration beam,and the consistency of the temperature frequency coefficient matches well,which enables the differential resonator to strongly suppress the temperatureinduced common-mode effects.During the temperature cycling process between-20℃ and 80℃,the equivalent acceleration drift of R1M1 and R2M2 were 341.6 mg and 414.6 mg,respectively.After using the differential temperature compensation algorithm,the equivalent acceleration drift was reduced to 1.19 mg.The minimum Allan variance measured statically at room temperature decreased from 1.42μg@0.85 s for R1M1 and 1.52μg@0.85 s for R2M2 to 0.23μg@7.15 s,indicating a significant improvement in the long-term stability of DMRA.In addition,the differential measuring method also eliminated common mode ambient noise in low frequency range,ultimately achieving a noise level of 220 ng=ffiffiffiffiffi Hz p@(0.2–0.8 Hz)for a prototype device with a measurement range exceeding±5 g.
