Study On Structure Of Gas-liquid Redistributor Apply To Offshore Packed Tower

Currently,it has become a trend that utilizing the deep gas floating production storage and offloading(FPSO)unit to explore offshore natural gas resources.And the pretreatment technology of the natural gas deacidification receives more and more attention.This technology is very mature on land,but the study about the tower and internal that used on FPSO unit is insufficient.The effect of a gas-liquid redistributor is to collect and distribute the nonuniform flow field in the packed deacidification tower,and it affects to gas-liquid mass transfer efficiency in the packing bed.In order to ensure the gas-liquid redistributor plays good performances in the offshore packed tower,its structure is supposed to get further study.This paper studied the structure design of gas-liquid redistributor used in offshore packed tower,using the method of combining hydraulics experiments and numerical simulation.A set of experimental equipment that can achieve different sloshing conditions or different bias current conditions and the corresponding numerical calculation model was established.The export flow’s uniformity and operating flexibility of the gas-liquid redistributor can be acquired by the result of experiments.The liquid level fluctuation and outlets’ velocity vector can be acquired by the result of simulation.A traditional trough plate gas-liquid redistributor was designed based on the structural design method of land,and the research about its performance under the conditions of static,sloshing and different bias current was carried out.The structural optimization schemes were proposed based on the analysis of the reasons for the decline of performance.The optimum structure form and structural parameters of the new type gas-liquid redistributor were determined by comparing the various optimization schemes.Then experiment and simulation were carried out to study the adaptability to ocean conditions of the new type gas-liquid redistributor,including the uniformity under different sloshing conditions,the ability of rectifying bias current,the adaptability to different sloshing periods and operating flexibility.All the above results show that traditional trough plate gas-liquid redistributor is influenced more by rolling and pitching.The reason is that the internal liquid is apt to flow when the trough plate gas-liquid redistributor is sloshing,leading to big liquid level differences and flow rate differences.So the traditional trough plate gas-liquid redistributor cannot be applied to the normal ocean conditions.The new type gas-liquid redistributor’s baseboard is divided reasonably.Not only can it meet the design requirements of gas channel and spray point,but also reduce the flow space of internal liquid.It’s helpful to maintain the uniformity of orifice flow under the condition of sloshing.Under the static condition,the uniformity of new gas-liquid redistributor’s flow rate is good,the effect of sloshing is very small,and the influence of the change of sloshing periods on distribution quality is also small.With the increase of bias current,the new gas-liquid redistributor’s rectification to regional bias current and differences of orifice flow rate is improved.But it is more suitable for medium and small degree of bias conditions.The operating load accounts for 61.5%~136.5% of the rated fluid and the operating flexibility of the new gas-liquid redistributor is about 2 under the normal sloshing conditions.The research contents and conclusions of this paper have indications to some extent for the design of high performance gas-liquid redistributor that used on FPSO unit.