GB2436370A - Horizontal calming baffle for smoothing fluid flow - Google Patents

Abstract

The calming baffle smooths liquid and gas flows. It consists of parallel horizontal beams which help to control turbulent flow typically created in an oil and gas separator inlet device. The design means that it is able to cope with a large range of flow rates, downstream turbulence and shear is further minimised, can cope well with sloshing, requires little to no maintenance or spare parts, has no moving parts and does not suffer from clogging like other similar devices. It is particularly useful in the oil and gas industry where turbulent flows can lead to inefficiencies in two and three phase separator vessels. The arrangement has a singular layer of baffles for the liquid phase but is double layered for the gas phase.

Description

<p>1 2436370 Horizontal Calming Baffle The calming baffle has been

primarily developed for the smoothing of liquid and gas flow for use within two and three phase separation vessels in the oil and gas industry.</p>

<p>l'he horizontal baffle assembly can be fitted shortly after the inlet device in a separator to complete the inlet-processing zone.</p>

<p>Vanes have been seen in many industrial applications as useful for redirecting fluid flow. Typically the leading edge of a vane will be used in a gas or liquid stream to redirect the flow so that the stream will follow the surface of the vane. The shape of the vane redirects the flow downstream or to the trailing edge of the vane. From here the flow direction is governed by the characteristics of the trailing edge. In the oil and gas industry perforated plates are commonly used. Typically the flow is forced through holes in the perforated plate.</p>

<p>The bulk liquids from an inlet device fall under gravity through a space within the inlet-processing zone, into a region bounded by the horizontally mounted distribution baffles. The purpose of the distribution baffle is to quieten the liquid flow prior to its entry into the liquid / liquid separation region, thus maximising liquid / liquid separation and suppressing the liquid surface turbulence particularly reducing the velocities in the horizontal plane. The horizontal baffle provides a high degree of surface control of the gas / oil interface, giving both secondary smoothing and flow distribution to the liquid flow. Its format has been developed in house using laboratory and computational experiments.</p>

<p>The horizontal baffle is a fully cross sectional assembly. As such, the baffle can play an extremely important part in also enhancing the gas distribution through the separator, minimising mal-distribution on the downstream demisting equipment, thus maximising gas / liquid separation. The separation efficiency is maximised because the baffle takes away the incoming momentum of the flow reducing the turbulence further downstream improving the laminar flow characteristics. By providing bulk degassing in the inlet processing zone of the separator there is also a positive effect on foam reduction, by removing the bulk of the primary cause of foam, i.e. gas in the oil.</p>

<p>The calming baffle assists in promoting rapid foam drainage back into the liquid.</p>

<p>The calming or re-distribution baffle is quite different in performance, both in stationary and dynamic (sloshing) situations compared with other "industry standard baffles" such as perforated plates. During sloshing the liquid will not travel back up the vessel due to the arrangement of the baffle thus reducing the risk of disturbing the inlet distribution. The calming baffles are comprised of two sets of horizontal beams with varying aspect ratios, depending upon the application, giving a much lower pressure drop in comparison, even when the aspect ratio or NFA (Net Free Area) is the same. There is a lower pressure drop in the calming baffle as opposed to the perforated plate due to the lack of sharp orifices. Perforated type baffles have a tendency to suffer from clogging. Due to its large openings the distribution baffle does not suffer from solid blocking and as such is ideal for any "dirty" duties.</p>

<p>The essential features of the baffle are the horizontal beams which each contain two 900 bends and three significant outer faces (those more exposed to the flow). The larger of these faces is the middle side which opposes the oncoming flow. The arrangement has a singular layer of baffles2for the liquid phase but is double layered for the gas phase. As each beam is made of just one piece of material then there is no need for attachment apart from to the supports thus making the structure more secure and more resistant to erosion. The horizontal beams are supported and held in place using thinner vertical beams behind. Typically the baffle covers the height and width of a vessel but removing some of the beams due to current internals in the separator will not significantly reducc the performance of the device. The construction of the baffle is typically stainless steel although any other suitable metal could be used.</p>

<p>The baffle contains no moving parts and has no set maximum and minimum energy boundaries allowing the baffle to perform well under large and small velocities. As the construction has no moving parts there is little wear occurring and no need for maintenance or spare parts.</p>

<p>Introduction to Drawings</p>

<p>The invention will now be described by way of example only and with reference to figures 1 to 3 of the accompanying drawings. In the figures I refers to the horizontal beams height and 2 to the horizontal beams width.</p>

<p>Figure 1 shows an isometric view of the calming baffle. The horizontal beams height will change slightly depending on the height of the vessel while the beam width remains fairly consistent. The distance between the beams depends on the conditions of the particular vessel but the area that is contained within the liquid section of the vessel should typically have a 50% open area while that contained in the gas zone should typically have a 22% open area. Both of these open areas are dependent and change depending on vessel flow conditions.</p>

<p>Figure 2 shows a side view of the calming baffle. The 900 angle can be clearly seen in item 1. The device forces fluid to travel through a parallel set of vanes and in a set direction.</p>

<p>Figure 3 shows a side view of the flow acting on a horizontal calming baffle. The theoretical flow is incoming at an angle and the baffle arrangement is altering the direction.</p>

Claims (1)

1. <p>Claims 1. Calming of liquid and gas zones.</p>

   <p>2. Improves laminar flow characteristics.</p>

   <p>3. The process will not suffer from clogging.</p>

   <p>4. The design requires no spare parts andlor maintenance within it operating life.</p>

   <p>5. The baffle has no moving parts.</p>

   <p>6. The process remains unaffected for a range of operating conditions.</p>

   <p>7. Large open area to reduce shear.</p>

   <p>8. The process prevents large amounts of backwash e.g. due to sloshing.</p>