Authors: S. Ripandelli, A. Corrente, V. Russo, A. De Martiis

Graphic abstract

Abstract

In the Oil & Gas field and for these applications is common the mist mineral oils generation (i.e. aerosol), with the risk of emission to the atmosphere with consequent air pollution. In a gas turbine, oil mist mainly comes from the lubricating fluid spilling out of the seals of the bearings placed along the shaft. Aerosol emissions are composed of a widely distributed oil particles of varying sizes, ranging from 0.01 micron to 10 micron. Because the toxicity of oil, auxiliary systems like the Oil Mist Eliminator (OME) are designed and used to remove it from air and to restrict aerosol emissions to the atmosphere. In the last years, it becomes more important to understand how much efficient these auxiliary systems are, indeed, there are regulated limits to the total amount of oil that can be released into the atmosphere. This limit is recommended to be lower than 5 mg/m3 in accordance with OSHA Permissible Exposure Limits. Literature shows that researchers are still involved in studying “solid” procedures to make a comprehensive and standard method for qualitative and quantitative analysis. In this paper we analyzed a FTIR based analytical laboratory method, employing C2Cl4 for liquid-solid extraction, to quantify the amount of oil emitted into atmosphere. The choice to employ FTIR is mainly due to its simplicity and rapidity, thinking about the possibility to apply this technique not only at laboratory, but even on field to evaluate and to monitor emission at operative conditions.

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Authors: S. Ripandelli, V. Russo, A. Corrente

Abstract

Auxiliary systems like the Synthetic Oil Mist Separator (SOMS) are used as an essential service to gas turbines. They are designed mainly to restrict aerosol emissions to the atmosphere. Aerosols emissions from gas turbines are composed of small oil particles of varying sizes, ranging from 1nm to 1000 nm. For this application, the aerosol is called “oil mist” because the temperature of the fluid is lower than vapor temperature during the dispersed phase resulting in the mist. It is a sub product of the gas turbine during operations. The amount of oil mist produced is influenced by time and other operational conditions of the gas turbine (rpm, energy production, wear, etc.). In this study we analyzed oil mist production from a gas turbine on site at two different operational conditions: Core Idle, when the gas turbine did not produce energy, and Full Load during energy production. The SOMS was designed to collect and separate oil from air, by coalescence, whereby millions of oil droplets moving through the SOMS and the microfiber cartridges combine together to form larger in size drops. These larger drops drain downwards and are collected at the bottom of the SOMS. Knowing the actual efficiency of the SOMS at operational conditions of the gas turbine is important, due to environmental limitations for emissions. Indeed, there are regulated limits to the total amount of oil that can be released into the atmosphere in these applications. This limit is recommended to be lower than 5 mg/m³ [1] in accordance with OSHA Permissible Exposure Limits (PEL). Nevertheless, it is not trivial to estimate the actual amount of oil released into the atmosphere. Literature shows that researchers are still involved in studying procedures to make a comprehensive and standard method for qualitative and quantitative analysis. In this paper we present our approach and results for in situ measurements. The measurement methods presented here were first evaluated at laboratory on a SOMS. Then these methods were used to evaluate the performance of the SOMS in situ on a gas turbine under operational conditions. Based on these results we believe that this protocol can be a good candidate to become a standard for in situ measurement of the efficiency of SOMS. Currently, many other improvements are under investigation.

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Authors – Team of the R&D Centre: S. Ripandelli, A. Corrente and V.Russo

Short Abstract

In the field of industrial filtration one of the critical points is the pressure drop (i.e. Dp is usually expressed in mbar) at filters items. An high Dp means an higher energy consumption and as consequence an higher cost.

In general Filter is composed by an housing (i.e. steel vessel) and one or more cartridges, capable to carry out the separation of the species, make with different filtration media. There are two contribution to the total Dp: Dp_V due to vessel and piping, and Dp_C due to the flow through the cartridges. It is important to know the two contributions separately for a correct design, in order to propose new technical solutions having an higher efficiency.

Filters R&D team built a new model to estimate this pressure drop and validated it thanks to the new LUBE Oil test bench (called Blue Edge at scale 1:1). Researchers extrapolated data about pressure drop of a filter hosting three Filters pleated cartridges [type F – hydraulic filtration] at different flow rate and oil viscosity.

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