JP4722840B2 - Device for splitting a two-phase stream into two or more streams having a desired gas / liquid ratio - Google Patents

Abstract

The invention is a device (30) for splitting a two-phase inlet stream (41) into two or more outlet streams (42, 43). The device can be designed to maintain close to identical vapor to liquid ratio in each of the outlet streams. The inlet stream to the device is routed via an inlet pipe (32) to a separator vessel (31). Below the inlet pipe entrance in the vessel an impingement plate (33) is provided to break down the high velocity of the stream and to direct the stream towards the inner walls of the separator where liquid will impinge and separate from the vapor phase. In the separator vessel, separation of the liquid and vapor phases is achieved. Inside the separator two vertical suction channels (34, 35) are located. These suction channels are in fluid communication with the two outlet pipes (44, 45) through which the outlet streams are leaving the separator. The lower ends of the suction channels are submerged in the liquid phase (39). The suction channels are provided with apertures (36) in the side walls. Vapor is flowing though the fraction of the apertures that are above the liquid surface in the separator. When vapor is flowing through these apertures a pressure drop across the wall of the suction channel is generated. Consequently liquid is lifted up into the suction channel. The liquid is mixed with the vapor inside the suction channel and the two-phase mixture is flowing upwards through the channel and is leaving the separator and two-phase stream splitter through the outlet pipes.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a two-phase inflow stream (eg, a stream consisting of a gas and a liquid) consisting of a light phase fluid (or a fluid consisting of a light phase) and a heavy phase fluid (or a fluid consisting of a heavy phase). Relates to a device for dividing the stream into two or more effluent streams. In this device, the gas / liquid ratio of each effluent stream is as desired. The flow rate of each effluent stream need not be the same. Without limitation, the present invention provides a two-phase process that flows in pipes or channels to be supplied to parallel heat exchangers, furnace tubes (or smoke tubes), air coolers, chemical reactors or piping equipment. Suitable for splitting a stream.

Related Art A large number of processing units are required to separate a two-phase stream, from a level that uses simple symmetric piping splits (or pipe splits) or T-tubes to higher performance two-phases. Various means are conventionally used up to the level of using a stream splitter.

  Devices for separating two-phase process streams can generally be divided into six types.

Type 1: Symmetric Piping Split Using Standard T-Tube Conventionally, when splitting a two-phase stream, a symmetric pipe split can be constructed using a standard T-tube. The two-phase stream is evenly distributed to each branch pipe according to the phase. An example of a symmetrical piping split that splits a two-phase stream into four effluent streams is shown in the isometric view of FIG. The two-phase inflow stream flows through the inflow pipe 1.

  The two-phase stream is sent to the first T-tube by the pipe 1, and the two-phase stream is divided into two outflow streams by the first T-tube. In the illustrated example, a 90 ° elbow 2 is arranged upstream of the T-tube 3. Due to the centrifugal force acting on the liquid, the liquid tends to flow near the outside of the inner wall of the elbow, while the gas tends to flow near the inside of the inner wall of the elbow. Thus, the elbow causes phase separation, causing gas and liquid to be distributed unevenly across the pipe cross section. In order to minimize the adverse effect on the separation function of the T-shaped tube 3 caused by the upstream elbow 2, it is necessary to provide the pipe 1 perpendicular to the surface defined by the illustrated T-shaped tube 3. . The two outflow streams separated by the T-tube 3 are further divided into two outflow streams by T-tubes 5a and 5b, respectively. An elbow 4a is provided on the upstream side of the T-shaped tube 5a, and an elbow 4b is provided on the upstream side of the T-shaped tube 5b. As in the case of the upstream elbow 2, in order to minimize the adverse effect on the separation performance of the T-tubes 5a and 5b caused by the upstream elbows 4a and 4b, the T-tubes 5a and 5b shown in FIG. It is necessary to provide the pipe 7 perpendicular to the two surfaces. Thus, by using a symmetric piping split, the incoming stream in pipe 1 is split into four product streams flowing in pipes 6a, 6b, 6c and 6d.

  Symmetric piping splits are considered the most widely used method for splitting a two-phase inflow stream into two or more outflow streams. So far, however, the principle of such symmetrical piping splits has not been able to distribute liquid and gas equally to each effluent stream, and in many cases each gas / liquid of the effluent stream The ratio was not the same. The main problem with symmetrical piping splits with standard T-tubes is that the stream splitting performance depends on the flow regime in the upstream pipe, and all the related The desired dispersed flow mechanism is not always maintained under certain conditions. A dispersed flow mechanism is a flow mechanism that exists in a flow channel or pipe, in which small droplets are uniformly distributed in a continuous phase of gas, or a flow in which small bubbles are distributed in a continuous phase of liquid. Mechanism (bubble flow). Also, the performance of a symmetric piping split can depend on piping provided upstream of the split. The main limitation of the symmetric piping split is that the flow rates of the effluent streams must be the same so that the gas / liquid ratio of each of the effluent streams is not significantly different. As other restrictions, it can only be divided into two, four, eight, sixteen, etc. outflow streams, and only a two-phase stream can be divided symmetrically. Therefore, such a symmetrical piping split cannot be divided into three, five, six, seven, nine... Effluent streams.

  The performance of a symmetrical piping split with a standard T-tube is thought to improve when chemicals are added that reduce the surface tension of the liquid upstream of the split. As the surface tension of the liquid is reduced, the dispersion flow mechanism will be achieved at a slower flow rate. Thus, acceptable performance of symmetrical piping splits is achieved over a wide range of gas and liquid flow rates. One example is described in US Pat. No. 5,190,105. In US Pat. No. 5,190,105, surfactant is injected from multiple injection wells upstream of the split that splits the two-phase stream of saturated vapor and water so that the quality (vapor The oil recovered from the oil reservoir is improved.

Type 2: Uses T-tube blades, baffles (or baffles) and pipe internals (or inserts) such as static mixers with special internals such as blades, baffles or static mixers By doing so, an attempt has been made to improve the division performance of a standard T-tube.

  A first example is described in US Pat. No. 4,396,063. In U.S. Pat. No. 4,396,063, a static mixer is placed upstream of a T-tube consisting of a Y-branch tube. In order to obtain good splitting performance with the same gas / liquid ratio in each effluent stream, it is preferable to use a dispersed flow. In a distributed flow mechanism, the two-phase mixture functions more or less as a single phase fluid. Small droplets will follow a gas flow at approximately the same speed, or a gas flow will follow a small droplet. Therefore, in a distributed flow mechanism, good splitting performance is often achieved with a T-tube. A static mixer is used upstream of the T-tube, thereby forming a protruding area on the surface of the inflow pipe perpendicular to the flow direction. When a liquid acts on such a surface, the liquid and the gas are separated. Therefore, if a static mixer is used, the desired dispersion flow mechanism (if present) will be disturbed, resulting in separation of undesirable liquids and gases. In addition, the use of a static mixer causes an additional pressure drop in the process system, which may increase the power consumption of the pump and / or compressor, resulting in additional operating costs. Static mixers are also susceptible to contamination due to contaminants such as scale and corrosion products.

  A second example is described in US Pat. No. 4,824,614. In the flow splitter of U.S. Pat. No. 4,824,614, the static mixer 22 is arranged in the inlet pipe upstream of the T-tube 14. At the T-tube 14, the incoming stream 30 is split into two outgoing streams 74 and 76. Between the static mixer 22 and the T-tube 14, a horizontal stratifier (or a stratification region) 24 is provided. In the stratifier, liquids from six different elevations are brought together. For example, fluid from the lowest first elevation will be sent to the effluent stream 76 and fluid from the second elevation will be sent to the effluent stream 76. Similar to the mixer of the first example, the mixer of the second example tends to cause undesirable separation of liquid and gas. Further, due to the static mixer, the operation cost may increase or it may be affected by dirt. Although not very practical, a stratifier to which such fluids are combined will only work if the gas and liquid are evenly distributed across the pipe cross section. U.S. Pat. No. 5,811,032 tests a mixer / stratifier assembly using a steam / water field. The test results show that steam and water can be better separated using a standard buffering tee than using a mixer / stratifier assembly. I understood.

  A third example is described in US Pat. In U.S. Pat. No. 5,811,032, various internals used in standard tees are tested by using air and water in the laboratory. Also, various internal tests have been conducted in the field to divide the steam / water mixture and lead it to parallel injection wells to improve oil recovery in the oil reservoir. Note that a static mixer provided upstream of the standard T-tube, a vertical flow baffle provided upstream of the standard T-tube, and two outflow branches of the standard T-tube. Tests were conducted on a flow restriction or nozzle and three common pipe inserts used in the section. In addition, a test is also performed on such a combination of three types of internal. As a result, it was found that the splitting efficiency was slightly improved only in the case of the static mixer and the vertical baffle. When a flow restriction or nozzle is used at the two outflow branches, the splitting efficiency is somewhat improved for the flow mechanism used in the test, but the liquid distributed unevenly in the cross-section of the inflow pipe and In the case of gas, it is not clear what the driving force is to distribute the liquid uniformly in the nozzle and outflow branch. No flow experiments have been performed in the laboratory with respect to dispersed flow mechanisms or bubble flow mechanisms (where there are droplets in a continuous phase of gas or where bubbles exist in a continuous liquid). The flow mechanisms evaluated are laminar, wavy laminar, slag and annular flows, which are predicted by using a two-phase flow map by Ovid Baker (" "How to size process piping for two-phase flow", hydrocarbon processing, October 1969, pp. 105- 116). Thus, when the flow rate is low and the ratio of the liquid is small, it is only found that the division performance of the standard T-tube with the internal or the standard T-tube without the internal is improved. Has been. Tests have not been performed on the preferred mechanisms with high flow rates, i.e. dispersed and bubbly flows. If the test is performed with a dispersed flow and a bubbly flow, the results may be different.

  Instead of using a special internal with a standard T-tube, an example of greatly improving the T-tube has been suggested. Examples of improved T-tubes are described in Japanese Patent (JP-A2) 62059397, US Pat. No. 4,528,919 and US Pat. No. 4,512,368.

Type 3: Predicting the flow mechanism utilized in the device industry that relies on the flow mechanism formed upstream of the split is difficult due to the lack of accuracy of the flow regime map. Most flow mechanisms are primarily based on two-phase flow mechanism data for air and water provided in small diameter pipes (pipes having a diameter of less than 2 inches). Therefore, the flow mechanism map is inaccurate in a high temperature, high pressure hydrocarbon / hydrogen system such as a hydroprocessing unit.

  In addition to the inaccuracy of the flow mechanism map, thermodynamic models that predict the quantity and nature of liquids and gases are also inaccurate. This is true, for example, for complex hydrocarbon systems where hydrocarbons are characterized by the use of pseudo components, and for complex hydrocarbon systems where equations of state are used to predict evaporation degree and fluid properties. Make an important sense.

  Also, the piping system of a processing plant has pipe fittings such as expansion, contraction, elbow, check valve, and is often complicated. As the two-phase stream passes through such pipe fittings, the general flow mechanism is distributed, so long straight piping is required to re-form the general flow mechanism. For example, as described above, the elbow tends to separate phases such that a dense liquid phase flows near the outside of the inner wall of the elbow and a light liquid phase flows near the inside of the inner wall of the elbow.

  For these three reasons, it is usually difficult to accurately predict the actual flow mechanism of a pipe or flow channel. Thus, it is usually difficult to maintain a single flow mechanism for all relevant operating conditions of the processing unit due to variations in operating conditions such as temperature, pressure, flow rate, fluid chemical composition, and the like. Nevertheless, many two-phase stream strippers are designed to work for only one flow mechanism.

  A first example of a two-phase stream splitter is described in US Pat. No. 4,516,986. Such a splitter comprises an internal pipe 12 inserted into the main pipe. A baffle 13 is disposed in an annular region provided between the internal pipe and the main pipe. The flow mechanism intended for the main pipe is an annular flow mechanism in which liquid flows through an annular ring near the pipe wall and gas flows at a high speed through the center of the pipe. A portion of the liquid flowing near the pipe wall will be collected in the closed end space 14. Liquid flowing out of the closed end space 14 flows through the external line 15 through the control valve 23. The gas obtained from the annular gas space 30 downstream of the baffle 13 is sent through the branch pipe 11. In the branch pipe 11, the gas and the liquid from the control valve are combined. A flow meter 20 provided to the two-phase stream of the branch pipe 11 is used to control the liquid flow. However, it is not described how the gas / liquid ratio can be accurately measured with a flow meter. Usually, to measure the gas / liquid ratio, the gas flow and the liquid flow must be measured separately. With other flow mechanisms other than the annular flow, such as slag flow, the splitting performance of the device may deteriorate. Even when the main flow mechanism in the main pipe 10 is an annular flow, the flow is disturbed by pipe fitting such as an elbow on the upstream side of the splitter. Therefore, although a straight piping part is required, this piping part will occupy an additional space with a processing unit. Moreover, there is a limit in the flow velocity range. If the total flow velocity is below the design value, the pressure drop across the baffle 13 will suddenly decrease and the pressure drop provided at the control valve 23 will decrease. At some point, the control valve may be fully open, making it impossible to control the fluid velocity. When equipment and control valves are used, the system is not as simple and robust as other two-phase splitters, increasing the pressure drop across the splitter. Larger pressure drops typically increase costs associated with processing unit transfer (or pumping) and / or compression. The patent specification describes how two effluent streams are generated. If more than two effluent streams are needed, more than one split system in series will probably be needed. In cases where many effluent streams are required, the split system can be somewhat complicated and the required pressure drop can be excessive.

  A second example of a two-phase stream splitter is described in US Pat. No. 4,800,911. In U.S. Pat. No. 4,800,911, the horizontal header 16 is provided with outflow branch pipes 14a, 14b, 14c. The outflow branch pipe on the upstream side is provided at a higher position, and the height of the outflow branch pipe gradually decreases toward the downstream side. If the flow mechanism in the header is an annular flow, the thickness of the annular liquid ring portion must be approximately the same at each outlet branch point having various heights, so that each The gas / liquid ratio in the branch stream is required to be the same. As mentioned above, it is unlikely that the flow mechanism is maintained in one certain flow mechanism in all relevant operating conditions. Furthermore, even if an annular flow can be maintained in the main line, it is expected that the gas / liquid ratio will affect the overall flow rate in each branch line. The higher the flow velocity in the branch line, the more gas will be drawn into the pipe and the higher the ratio of gas to liquid. If the flow mechanism of a certain mode of operation is different from what is expected, for example laminar flow, the phases will be distributed to the outflow bifurcations significantly unbalanced.

  A third example of a two-phase stream splitter is described in US Pat. No. 4,574,837. Certain phase separation in the horizontal main pipe 10 described in US Pat. No. 4,574,837 is believed to be known. Since the main pipe is provided with openings of various heights, the fluid flows through the branch pipe 13 after flowing through the annular chamber 12. By selecting the appropriate flow area of the openings in the top and bottom of the pipe 10, the gas / liquid ratio of the stream in the branch pipe is set. If the flow region in the upper opening is faster than the flow region in the opening at the bottom of the pipe, the ratio of gas to liquid is higher in the branch pipe. Such devices work only for laminar and waved laminar mechanisms. Also, with such a device, the stream can be split at the desired gas / liquid ratio only if the liquid level in the main pipe is known in advance. As a result, the device can only work for slow flow rates and can only work for defined gas / liquid ratios and properties. Most industrial applications are characterized by high flow rates and highly variable gas / liquid ratios and properties.

  Other examples of stream splitters are described in US Pat. No. 4,574,827 and US Pat. No. 5,437,299. The splitter described in US Pat. No. 4,574,827 and US Pat. No. 5,437,299 relies on some flow mechanism formed upstream of the split.

Type 4: Device Utilizing Centrifugal Force US Pat. No. 5,059,226 describes a two-phase flow splitter utilizing centrifugal force. The centrifugal splitter has a fluid inlet 28 in the tangential direction leading to the vortex chamber 23. At the bottom of the vortex chamber there is a central hub 38 and vane 39 that guide the swirling gas and liquid through the outlet opening 36 to the outlet channel 37. However, it is not easy to understand what the driving force for distributing the liquid phase is. Also, only one inlet 28 is provided on one side of the device, and the fluid inlet is not symmetrical. Although the liquid swirls along the inner wall of the vortex chamber, it cannot be expected that the flow and liquid layer / film thickness will be uniform due to the asymmetric design. As a result, some vanes 39 collect more liquid than other vanes 39, so that liquid is not optimally distributed to the outlet chamber 37.

Type 5: Device that disperses a flow using external energy An example of a device that disperses a flow using external energy is described in European Patent (EP-B1) No. 0003202. A rotary stirrer and motor 32 provided on the shaft 28 are used upstream of the split that divides the inflow stream into the outlet channels 4a, 4b and 4c, thereby dispersing the liquid and gas mixture. Yes. In such a device, the device is considered to function regardless of variations in flow rate and fluid properties because the distributed flow mechanism is generated by a mechanism applied to the shaft 28. The main problem associated with this type of device is that it facilitates a good seal between the shaft 28 and the pipe / bend 21 when high pressures such as hydrocracking (up to 300 bar) are used. It cannot be achieved (it cannot be cheaply designed). There are also high initial costs, maintenance costs for rotating machines, and power consumption for the motor.

Type 6: A device that separates the gas and liquid phases into the effluent stream after separating the gas and liquid in the inflow stream , using a conventional gas / liquid separator and conventional instrumentation in FIG. Fig. 4 shows a first example of a flow splitter that splits a two-phase inflow stream into three outflow streams. The gas phase is transferred to the control valves 15a, 15b and 15c provided in parallel via the gas outflow line. Control valve position or lift (or valve opening) is controlled by flow controllers 16a, 16b and 16c so that the gas through each control valve has the desired flow rate. Flow is measured using conventional techniques such as a combination of a ΔP transmitter and an orifice plate or a venturi tube. The flow controller is connected to the pressure controller 17. The pressure controller changes the flow settings for the flow controllers 16a, 16b and 16c so that the desired pressure is maintained at the separator 10. The liquid phase 13 is transferred via a liquid outflow line 18 to control valves 19a, 19b and 19c provided in parallel. The position or lift (or valve opening) of the control valve is controlled by flow controllers 20a, 20b and 20c so that the liquid passing through each control valve has the desired flow rate. Flow is measured using conventional techniques, such as a combination of a ΔP transmitter and an orifice plate, for example. The flow controller is connected to the pressure controller 21. The level controller changes the flow setting values for the flow controllers 19a, 19b, and 19c so that a desired level is maintained in the separator 10. The combination of the gas stream transferred from valves 15a, 15b and 15c and the liquid stream transferred from valves 19a, 19b and 19c results in three two-phase effluent streams 22, 23 and 24. .

  The instrumentation used in the two-phase stream splitter as shown in FIG. 2 is somewhat complicated. This is because the components such as the transmitter, the control valve and the controller are complicated and not only have a large number of them, but also can be a failure and a malfunction. If the control system fails or fails, the downstream stream system will be compromised if the gas to liquid ratio is too high or too low. For example, when the ratio of the gas to the liquid in the stream flowing in the pipe suddenly increases, the pipe is overheated, so that the pipe may be torn or coke may accumulate in the furnace pipe. Also, for example, if the reactor is operated in a state where the ratio of gas to liquid is low, coke may accumulate suddenly in the catalytic hydrogen treatment reactor provided in parallel, and as a result, even in a short time. Will run out of hydrogen. Furthermore, if the control system becomes complicated and the size of the separator vessel 10 increases, the cost of the splitter will increase.

  A second example is described in US Pat. No. 4,293,025. The two-phase flow splitter described in US Pat. No. 4,293,025 includes a separator vessel 10 with a two-phase inlet nozzle 11. Since the buffer plate 14 is arranged below the inlet nozzle, the incoming stream supplied at a high speed is weakened. The separator is provided with two or more chimneys 12. The upper end of the chimney is open so that gas can flow into the chimney. The chimney is provided with an opening 13 through which liquid can flow into the chimney. A cap 16 is disposed above the upper end of the chimney so that liquid is not directly guided from the upper end of the chimney. The liquid flow supplied to each chimney is determined by the liquid head above the opening and the flow surface (or flow area) of the opening. When the liquid level in the vessel is a predetermined level, the liquid flow flowing to each chimney is substantially constant. Therefore, such a two-phase stream splitter is a liquid head whose driving force distributes the liquid into parallel effluent streams, and in such a splitter, each effluent rather than a constant gas / liquid ratio. In the stream, the liquid flow is constant. Another problem associated with stream splitters where the propelling force being dispensed is a liquid head is that the range of liquid flow is limited. The area of the opening 13 needs to be sized so that the liquid level is intermediate at the designed liquid flow rate. When the liquid flow rate is increased by, for example, 50% in one mode of operation, the liquid level will be approximately 2.25 times higher than the designed liquid level, so that the liquid will flow out of the chimney and the liquid will be desirably distributed into the effluent stream. Will not be. If the liquid flow is, for example, 50% slower than the designed liquid flow, the liquid level will be only about 25% of the expected liquid level. Low liquid levels result in poor liquid dispensing performance due to high sensitivity to waves, uneven equipment and other manufacturing tolerances. Providing an opening at a higher position can increase the liquid flow range of the splitter, but the liquid distribution performance at the design point is reduced compared to a splitter with an opening only at one height. It will be.

  Other examples of splitters in which the propulsive force for uniformly distributing the liquid into each effluent stream is at the liquid level are US Pat. No. 4,662,391, Japanese Patent (JP-A2) 03113251 and Japanese Patent ( JP-A2) 02197768.

A third example of a stream splitter that separates the liquid and gas phases is disclosed in US Pat. No. 5,250,104. In such an example, the two-phase mixture flowing in the pipe 14 is separated by the separator 12. The gas phase is divided into two streams by a T-tube 20. The two gas streams pass through orifices 22 and 24, respectively. The pressure drop ΔP _V of the gas flow as it passes through the orifice is approximately proportional to the square of the volume flow rate of the gas. The pressure drop ΔP _L of the liquid flow as it passes through the liquid lines 32 and 34 is due to the difference in height between the liquid level at the sump (or sump) 30 and the liquid level at the liquid tube ends 40, 42. It consists of a static term ΔP _SL and a friction term ΔP _FL . ΔP _FL is approximately proportional to the volume flow rate of the liquid. Since the gas and liquid passages provided in the splitter are parallel passages, the pressure drop is the same:

Flow face of the air orifice and liquid tubes are those having a size for a certain gas flow rate Q _V and a certain liquid flow rate Q _L. For example, if the actual gas flow is 50% faster during certain operating modes, ΔP _V will be 125% higher than expected. Since the liquid flow does not change, ΔP _FL also does not change. In order to satisfy the equation (1), ΔP _SL needs to be increased by 1.25 × ΔP _V. Therefore, the liquid level in sump 30 needs to be significantly reduced, and at some point there may be no liquid level in the sump, causing both gas and liquid to enter liquid lines 32 and 34. In such a case, the liquid distribution to the parallel lines 32 and 34 is insufficient. On the other hand, if the gas flow is reduced by, for example, 50% from the gas flow designed for a certain mode of operation, the ΔP _V will be 75% less than expected. In such a case, the liquid level in sump 30 rises considerably and overflows from the sump, causing liquid to flow to orifices 22 and 24, resulting in uneven distribution. Such a splitter will only work properly if the gas and liquid flow rates are at the designed (or intended) flow rates. Since most industrial applications usually have the characteristics of large variations in liquid and gas flow rates and large variations in liquid properties such as density, viscosity and surface tension, as well as gas properties, the liquid flow and flow rates of such splitters The flow range is insufficient.

SUMMARY OF THE INVENTION The present invention is a device that splits a two-phase inflow stream into two or more outflow streams. Such a device can be designed such that the gas / liquid ratio (or ratio of gas to liquid) of each effluent fluid is approximately constant.

  One embodiment of the inventive splitter is shown in FIGS. 3A, 3B and 3C. The inflow stream is sent to the separator vessel via the inflow pipe. A buffer plate (or impingement plate) is provided below the inlet of the inflow pipe of the vessel. The buffer plate reduces the high speed of the stream and directs the stream to the inner wall of the separator, so that the liquid collides with the inner wall of the separator and the liquid and gas phase are separated. In the separator vessel, the liquid phase and the gas phase are separated.

  Two suction channels provided vertically are arranged inside the separator. Such a suction channel is in fluid communication with the two outlet pipes. The effluent stream will be discharged from the separator via such effluent pipe. The lower end of the suction channel is immersed in the liquid phase. An opening is provided in the side wall of the suction channel. The gas flows through an opening located above the liquid level (or liquid level) in the separator. When the gas passes through the opening, a pressure drop occurs in the suction channel wall. As a result, the liquid is sucked into the suction channel and mixed with the gas in the suction channel. The resulting two-phase mixture flows upward in the channel and is discharged from the separator and two-phase stream splitter via an outlet pipe.

  The liquid level in the separator is mainly determined by the flow rate of the gas entering the vessel. If the gas flow rate is slow, the liquid level increases, and if the gas flow rate is fast, the liquid level decreases. Depending on the liquid flow rate, the liquid level is not significantly affected.

Unlike the prior art as described above, the present invention has the following advantages:
A) In the splitter of the present invention, the gas / liquid ratio of each of the effluent streams can be kept substantially constant. Alternatively, the splitter of the present invention can be designed such that the gas / liquid ratio of each of the effluent streams has a particular different value.
B) The splitter of the present invention can be designed regardless of the intended split ratio. Further, in the present invention, the splitter can function even when the actual division ratio in a certain operation state is different from the intended division ratio.
C) The splitter of the present invention works equally well whatever the flow mechanism in the inlet pipe.
D) The splitter of the present invention is not sensitive to (or sensitive to) the layout upstream or downstream of the piping system. For example, performance is not affected by pipe fittings such as elbows or valves upstream of the splitter.
E) Using the splitter of the present invention, multiple effluent streams can be formed. Although symmetric piping splits using impact tees can form two effluent streams, four effluent streams or eight streams,... Three effluent streams, six effluent streams, seven streams or nine streams, etc. can be formed.
F) The splitter of the present invention has a simple and robust design. The instrument is not used and has no moving parts. Little maintenance is required and there is no need for plant operators to pay attention.
G) The splitter of the present invention is an open system and is hardly affected by dirt. Using a splitter in the processing unit does not affect the concept of overpressure protection. In the hydrogen treatment unit, the relief valve (or safety valve) arranged on the downstream side of the splitter protects the equipment arranged on the upstream side of the splitter from overpressure.
H) No matter how large the downstream pressure drop, the splitter pressure drop is small (˜0.05 bar at design conditions).
I) The splitter of the present invention is compact and has a cost-effective design.

BACKGROUND OF THE INVENTION Upstream of various industrial process equipment, it is required to split a two-phase stream into two or more effluent streams such that each effluent fluid has the same gas / liquid ratio. Examples include the following:
In process furnaces, parallel furnace tubes are most often used for process fluids to avoid excessively large furnace tube diameters and to allow economical furnace designs. Yes. Therefore, it is necessary to divide and supply the supply stream to parallel furnace tubes provided on the upstream side of the furnace.
• Modern processing plants often use heat exchangers connected in parallel, such as a combined shell and tube heat exchanger. The use of heat exchangers connected in parallel in this way is to avoid an excessively large tube bundle diameter and / or to optimize heat integration in the processing plant. It is.
・ Bundled air coolers are often arranged in parallel. This is because the bundle size is limited, and when the length of the inflow header is excessively long, the fluid distribution to the parallel air cooler pipes is insufficient.
• Chemical reactors such as trickle bed reactors (or trick bed reactors) can be configured in parallel. For high pressure applications, parallel configuration can reduce the reactor diameter and lower the overall reactor cost. When retrofitting (or upgrading) a processing plant that needs to add more catalyst to an existing plant, from an economic perspective, adding a new chemical reactor in parallel to an existing chemical reactor rather than in series Is often very attractive. This is because, when adding a new reactor in series to an existing reactor, the pressure drop across all reactors is considerably increased, necessitating replacement / upgrade of pumps and / or compressors, increasing costs. On the other hand, when a new chemical reactor is added in parallel, the pressure drop is actually reduced, and the plant throughput can be increased even with the same pump and compressor.

  So far, it has hardly been possible to split a two-phase stream into a plurality of effluent streams with equal liquid / gas ratios. If the effluent liquid / gas ratios are not equal, the following results will be produced:

Because the heat capacity of the furnace gas is greater than the heat capacity of the liquid, a furnace tube that accepts a stream with a high gas to liquid ratio will be hotter than a furnace tube that accepts a stream with a low gas to liquid ratio. As such, the maximum allowable tube material temperature can even fall below the estimated heat exchange for the furnace. In this case, the furnace cannot transfer the heat originally intended, and as a result, the production rate of the processing unit is lowered. In hydrocarbon treatment, the higher the tube metal temperature, the greater the coke generation rate at the wall of the tube. As a result, it is necessary to stop the unit for removing the coke from the furnace tube early. Also, when gas and liquid are distributed to parallel furnace tubes with an automatic control system (flow control valve), if the control system fails, one or more furnace tubes may not suddenly pass the liquid flow. As a result, the furnace tube may overheat and burst.

If the gas / liquid ratio is not equal between the heat exchanger and the air cooler in parallel, the total heat transfer capacity is considerably reduced. This is especially true for critical applications where the temperature of the cold stream and the temperature of the hot stream are very close. For example, the heat transfer system is composed of two parallel heat exchangers A and B, where the heat exchanger A receives a stream with a high gas to liquid ratio and the heat exchanger B is a liquid Consider the case of accepting a stream with a low gas to gas ratio. Since the propulsive force ΔT of the heat exchanger A is lower due to the lower heat capacity of the stream, the amount of heat transfer in the heat exchanger A is smaller. Since the propulsive force ΔT of the heat exchanger B is higher due to the higher heat capacity of the stream, the amount of heat transfer exchange in the heat exchanger B is higher. In this case, more heat transfer in the heat exchanger B is not enough to compensate for the lower heat transfer in the heat exchanger A, and overall the total amount of heat transferred in the heat exchanger is Will be reduced. If the heat transfer is less than that expected in a heat exchanger, the production rate of the process will slow down and may result in severe economic consequences.

  In some cases, non-uniform distribution of liquids in parallel heat exchangers can cause fouling, blockage and / or corrosion. For example, one example is the case of using parallel heat exchangers that vaporize liquid. Process plants are designed to not completely vaporize (or evaporate) in heat exchangers, since process streams that do not typically vaporize are not contaminated. That is, the “dry spot” is not reached. When a “dry spot” occurs at a certain location of the heat exchanger, the contaminants that are originally dissolved or dispersed in the liquid are accumulated on the heat transfer surface because the liquid disappears. With one of the heat exchangers in parallel receiving a liquid that is well below expectations, such a heat exchanger will have a dry spot, even if not anticipated at the time of plant design. As a result, the problem of fouling and / or blockage in the heat exchanger will be exacerbated and subsequently the heat transfer rate will be reduced and the unit for cleaning the heat exchanger will have to be shut down early.

As another example, a case where a bundled air cooler for a product is used in a hydrogen treatment unit can be mentioned. As the reactor effluent cools, ammonia salts such as NH ₄ Cl and NH ₄ HS accumulate, which can cause serious corrosion and plugging problems. Therefore, washing water is added to dissolve the ammonia salt. When a process stream containing cleaning water is divided and supplied to parallel bundled air coolers, the distribution of cleaning water may be inadequate, and in bundles of air coolers where little or no cleaning water is supplied. Corrosion and blockage problems arise.

In parallel chemical reactors (eg, trickle bed reactors) provided in a chemical reactor hydroprocessing unit, it is very important that the same gas / liquid ratio be obtained at the inlet of each reactor. In a hydroprocessing reactor in which a hydrocarbon component and hydrogen react in the presence of a solid catalyst (for example, a hydrocracking reactor), if the ratio of gas to liquid in the feed supplied to the reactor is small, the hydrogen content in the reactor is reduced. Pressure is lowered. As a result, the reaction rate becomes low, the coke accumulation rate becomes high, and the catalyst is deactivated. Also, if the ratio of gas to liquid in the feed supplied to the reactor is small, the result is that the expensive loading of the catalyst molecules in the reactor is impaired, even with a short operating time.

DETAILED DESCRIPTION The splitter of the present invention can be designed to obtain the required split ratio (or distribution ratio). The split ratio is defined as the total mass flow of the effluent stream divided by the total mass flow of the inflow stream. For example, in the present invention, not only can the division ratio be designed to be 50% / 50%, but the division ratio can also be designed to be 5% / 95%. A two-phase splitter is an open system that uses no control valves and has a low overall pressure drop. Therefore, it is not the two-phase splitter itself that determines the split ratio, but the hydraulic capacity of the downstream flow system. Even if the split ratio deviates from the split ratio intended by the two-phase splitter, approximately the same gas / liquid ratio can be obtained in each of the effluent streams by appropriate design of the splitter. The reason is as follows:

  For example, the stream splitter is designed so that for the suction channel A and the suction channel B, the two-phase inflow stream is split into two outflow streams with a split ratio of 30% / 70% respectively. A case will be described as an example. In general, in such a design, the openings of the two suction channels have different sizes, and the cross-sectional areas of the two suction channels are different. In some modes of operation, the split ratio may be 40% / 60% instead of the 30% / 70% intended for a two-phase splitter. In this case, an amount of gas exceeding the initial expectation flows into the suction channel A from the opening provided in the side portion. As a result, the pressure drop from the outside to the inside of the suction channel A becomes larger, and as a result, more liquid is sucked into the suction channel. Further, due to the lower split ratio, an amount of gas less than the initial expectation flows into the suction channel B through the opening on the side of the suction channel B, and the outside of the suction channel B. The pressure drop from the inside to the inside becomes smaller. As a result, less liquid will be drawn into the suction channel. In this way, a design is made to compensate for different division ratios.

  If the split ratio for a given suction channel in an operating mode is higher than expected, more gas will flow and more liquid will flow. Similarly, if the split ratio for a given suction channel is less than expected, less gas will flow and less liquid will flow. As a result, the ratio of gas to liquid in the outlet pipe is not significantly affected by changes in the split ratio.

  In FIG. 4, a process flow diagram of a processing system with heat exchangers, instrumentation and furnace tubes installed in parallel is shown, but FIG. 4 shows the same gas / liquid in each of the effluent streams. A first example is shown for the performance in which the ratio is maintained. The heat exchanger into which the hot streams 58 and 65 flow and the furnace 61 are used to heat the cold two-phase feed stream 50. First, the splitter 51 of the present invention splits the cold stream 50 into three streams 52, 53 and 54. The effluent stream 52 flows through the train A consisting of the shell side of shell and tube heat exchangers 55 a, 55 b, 55 c and 55 d and the conduit 67 of the furnace 61. The effluent stream 53 flows through the train B, which consists of the shell side of the shell and tube heat exchangers 56 a, 56 b, 56 c and 56 d and the line 68 of the furnace 61. The effluent stream 54 passes through the train C, which consists of the tube side of the shell and tube heat exchangers 57a, 57b and 57c and the control valve 69. Outflow stream 62, outflow stream 63, and outflow stream 60 are combined to form product stream 64. Table 1 shows the flow rates and properties of the gas and liquid designed in the splitter 51.

  The splitter 51 is designed so that the division ratio with respect to the train A, the train B, and the train C is 40% / 40% / 20%, respectively. The aim is that each of the effluent stream 52, effluent stream 53 and effluent stream 54 has the same gas / liquid ratio. If the actual split ratio is the same as the designed split ratio of 40% / 40% / 20%, the gas / liquid ratio of the three effluent streams 52, 53 and 54 will be approximately the same. However, it was found that the pressure drop at a given flow rate in train A was 20% greater than expected. The difference in flow resistance was attributed to the different piping layouts of the two parallel trains A and B and slightly different heat exchanger and furnace designs. It was also found that the pressure drop at a given flow rate in train C was 30% greater than originally expected. The lower flow resistance for tray C was attributed to the higher flow conditions controlled by control valve 69. Due to the different flow resistance of the parallel flow system, the split ratio was different from what was expected.

  In the following, the difference in the gas / liquid ratio of each of the parallel trains resulting from the different expected flow resistances of train A and train C is evaluated using nine sets of gas and liquid flow rates. The set of gas and liquid flow rates evaluated and the results are shown in Table 2. The gas flow and liquid flow represent 50%, 100% and 200% of the designed gas and liquid flow rates, respectively. Table 2 also shows the results obtained from the evaluation, ie, ΔP in the splitter, ΔP in the three trains, gas / liquid ratio and% DVLR for streams 52, 53 and 54. Note that% DVLR is defined by the following formula:

ここで、ＶＬ_ｉおよびＶＬ_ｆｅｅｄは、それぞれ、流出ストリームｉの気体／液体比（即ち液体に対する気体の体積割合）および流入供給ストリームの気体／液体比（即ち液体に対する気体の体積割合）であり、Ｎｓｐｌｉｔは、スプリッターから得られる流出ストリームの数である。

Where VL _i and VL _feed are the gas / liquid ratio of effluent stream i (ie, the volume ratio of gas to liquid) and the gas / liquid ratio of the incoming feed stream (ie, volume ratio of gas to liquid), respectively. Nsplit is the number of effluent streams obtained from the splitter.

  As can be seen from Table 2, the given splitter design showed excellent performance over a wide range of gas and liquid flow rates, even when the downstream flow resistance was different from the original expectations.

  The gas / liquid ratio varies between 1.3 and 21.5, and the pressure drop in the train varies from 1.3 bar to 20.9 bar. The average% DVLR produced by more than 20% flow resistance of train A and less than 30% flow resistance of train B is as low as 2.97%.

  Splitter performance may be affected by mechanical errors in the manufacture and installation of the splitter. In particular, the performance of the splitter is affected by the relative height of the suction channel and the flow surface of the suction channel opening.

A second example of the application of the splitter of the present invention is shown in the process flow diagram of FIG. The existing trickle bed 75 packed with 190 m ³ catalyst particles is too small to obtain the desired product at the desired speed. Therefore, it is necessary to add 90 m ³ catalyst additionally. Instead of providing a new catalyst in series with the existing reactor, a new reactor 74 is provided in parallel with the existing reactor 75. The splitter 71 of the present invention is used to split the two-phase feed stream 70 into two effluent streams 72 and 73 that are sent to reactors 75 and 74, respectively. The division ratio divided into the reactor 74 and the reactor 75 is 32% / 68%. Downstream of the reactor, the effluent stream 76 from the reactor 74 and the effluent stream from the reactor 75 are combined to obtain a product stream 78. Although the suction channels of the splitter 71 are intended to be the same height, in this second example, the suction channel A corresponding to the stream 72 is 10 mm higher than the suction channel B corresponding to the stream 73. ing. Further, the flow surface of the opening of the suction channel A is 2% larger than the intended area, and the flow surface of the opening of the suction channel B is 2% smaller than the intended area. Yes. Due to the difference in the height of suction channel A and suction channel B and the flow area of the opening, the ratio of gas to liquid is higher in stream 72 than in stream 73.

  The splitter 71 is designed for gas and liquid flow rates as well as gas and liquid properties as shown in Table 3.

  In the following, the differences in gas / liquid ratio and% DVLR (defined by equation (2)) caused by errors in manufacturing and installation as described above are evaluated over a wide range of operating conditions. The operating conditions evaluated (shown in Table 4) correspond to 50%, 100% and 200% of the intended flow rates of gas and liquid, respectively. Table 4 shows the results obtained from the evaluation, ie, ΔP in the splitter, ΔP in the reactor, gas-liquid ratio (volume ratio) and% DVLR for streams 72 and 73.

  As can be seen from Table 4, excellent splitting performance was shown over a wide range of gas and liquid flow rates, even when there were errors in manufacturing and installation.

  In the two examples shown in FIGS. 4 and 5, the splitter is designed such that each effluent stream has the same gas / liquid ratio, but different effluent streams with different gas / liquid ratios are formed. Stream splitters can also be designed to For example, a two-phase inflow stream is divided into three outflow streams so that the split ratio is 20% / 20% / 60% and the gas / liquid ratio (volume ratio) is 10/12/20. Splitting splitters can be designed. It should be noted that in most industrial applications where a two-phase stream splitter is used, it is desirable that the gas / liquid ratio of each effluent stream be the same.

  The separation of gas and liquid performed in the separator of the present invention is not necessarily the same as in a conventional phase separator. It is sufficient to separate the bulk portion of the liquid from the gas. Since the gas is evenly distributed, the smaller liquid delivered with the gas will be distributed to the suction channel. Therefore, the separator of the two-phase steam splitter can be designed so that the gas linear velocity is higher than that of the conventional phase separator and the cross-sectional area is reduced. Also, the liquid residence time required by the separator of the two-phase stream splitter is considerably shorter than the liquid residence time required by a conventional separator equipped with an instrument as shown in FIG. ing. Conventional separators with instrumentation have a liquid residence time of 5 to 20 minutes, thus allowing a response time to the level control system, and workers in the event of an automatic control system failure. Manual operation is possible. In a two-phase stream splitter, the level (or liquid level) is corrected to some degree quickly and is mainly set by the gas charge. Therefore, the liquid residence time in the separator of the two-phase stream splitter is as short as 5 seconds. Overall, the two-phase stream splitter separator is much more compact than the conventional phase separator used in the equipment industry. For example, the size and cost of the pressure vessel of the splitter 51 of FIG. 4 designed for the gas and liquid flow rates and characteristics shown in Table 1 can be compared to the pressure vessel of a conventional phase separator as shown in FIG. Compared. This conventional phase separator is designed for gas and liquid flows and their characteristics as shown in Table 1. The results are shown in Table 5.

  The cost shown in Table 5 is the cost of a vessel provided with an internal such as a suction channel. Installation costs for foundation work, installation, insulation work, piping and instrumentation are not included. Therefore, in general, the total installation cost is 3 to 4 times the equipment cost shown in Table 5. As can be seen from Table 5, the splitter of the present invention is more compact and less costly than using a conventional phase separator.

  3A, 3B, 3C, 6A, 6B, 7A, 7B, and 8 show another structure of the splitter of the present invention. Such drawings are merely used to illustrate the present invention and alternative embodiments thereof, and are therefore intended to limit the inventive concepts disclosed herein or to be used as construction drawings. is not. In other words, the drawings do not limit the scope of the present invention. The relative dimensions shown in the drawings are not equivalent to, nor are they proportional to, commercial or industrial aspects.

  Reference will now be made to the drawings in which aspects of the invention are shown. The splitter 30 shown in FIGS. 3A, 3B, and 3C is a splitter that divides the incoming stream 41 into two outgoing streams 42 and 43. The splitter 30 includes a vessel 31 having an inflow pipe 32 and two outflow pipes 44 and 45. The inflow pipe 32 is connected to the wall portion of the vessel 31, and a seal is formed to prevent fluid leakage. The lower end of the pipe 32 is open so that the inflow stream 42 can enter the vessel 31. The buffer plate 33 and the side wall 40 constitute a flow channel. In such a flow channel, since the incoming stream 41 is divided into two streams, the two streams are guided toward the cylindrical wall portion of the vessel 31. Each suction channel consists of a circular tube having an open upper and lower end. The lower end of the suction channel is immersed in the liquid 39. The upper end or outlet of the suction channel 34 is connected to the outflow pipe 44, and the upper end or outlet of the suction channel 35 is connected to the outflow pipe 45, so that two flow channels discharged from the vessel 31 are connected. Is formed. A seal for preventing fluid leakage is formed between the wall portion of the vessel 31 and the outflow pipes 44 and 45. The suction channel 34 is provided with an opening 37 on the side of the pipe, and the suction channel 35 is provided with an opening 36 on the side of the pipe.

  During operation (or operation), the two-phase inflow stream 41 flows into the vessel via the pipe 32. Such a two-phase jet impinges on the buffer plate 33, thereby reducing the high speed of the stream, leading the stream toward the cylindrical wall of the vessel, and the liquid phase 39 and the gas phase in the vessel 31. 38 is separated. The liquid phase is collected in the heavy phase collection region at the bottom of the vessel while the gas phase is collected in the light phase collection region at the top of the vessel. The gas 38 flows through a part of the openings 36 and 37 on the side of the suction channel located above the liquid level. Since the gas flows through the opening in this manner, a pressure drop occurs from the outside of the suction channel toward the inside of the suction channel, and the liquid is sucked into the suction channel. The liquid 39 flows through the opened lower ends of the suction channels 34 and 35, or flows through a part of the openings 36 and 37 located below the liquid surface of the vessel 31. In the suction channel, liquid and gas are mixed. The resulting two-phase mixture flows upward in the direction of its outlet in the suction channel, so that the two-phase mixture is discharged from the vessel 31 via the outflow pipes 44 and 45.

  The inflow inlets are preferably arranged symmetrically between the suction channels as shown in FIG. 3A. Such a symmetrical arrangement minimizes the cross-sectional area of the vessel required for gas / liquid separation and delivers small droplets to more evenly occupy the gas passages. The splitter is preferably designed so that the incoming stream that is fed impinges on the plates and walls as shown in FIGS. 3B and 3C. When the supplied inflow stream collides with the plate and the wall, the liquid and the gas phase are easily separated, and the high-speed inflow jet reaches the liquid level of the vessel, so that the liquid again entrains. It will accompany or wave.

  The total area of the suction channel opening is selected so that the liquid level in the vessel is at the desired level. As the area of the opening increases, the pressure drop of the gas decreases. In that case, the liquid level will be higher so that the reduced pressure drop matches the vertical height required to aspirate the liquid. Conversely, as the area of the opening decreases, the liquid level decreases. The area of each suction channel opening can be used to set the gas / liquid ratio of the effluent stream obtained from the suction channel. When the area of the opening of the suction channel A is larger than the area of the opening of the suction channel B, the gas / liquid ratio of the effluent stream obtained from the suction channel A is equal to the gas / liquid ratio of the effluent stream obtained from the suction channel B. It becomes larger than the liquid ratio. The cross-sectional area and shape of each suction channel will affect the liquid level in the vessel and the gas / liquid ratio of each effluent stream.

  The opening of the suction channel shown in FIG. 3A is a circular hole. However, the opening may be a vertical slot (or a vertical slot). Alternatively, the opening may have other shapes such as a V shape, a triangular shape, a rectangular shape, a polygonal shape, and an elliptical shape. The opening region may not extend evenly in the height direction of the suction channel. For example, the suction channel may be provided so that the opening near the bottom has a smaller area and the opening near the upper end has a larger area.

  The suction channel shown in FIGS. 3A and 3B has a circular cross section, but may have various other cross sectional shapes such as a triangle, a rectangle, an ellipse, and a polygon. Also, the cross section of the suction channel may vary along the length of the suction channel.

  The bottom of the suction channel shown in FIG. 3A is open to allow liquid to flow. However, in most cases, the dividing performance can be improved by closing the bottom of the suction channel and allowing all of the liquid to flow from the side opening of the suction channel located below the liquid level.

  The suction channel of the splitter shown in FIGS. 3A and 3B is provided vertically. However, the suction channel may not be entirely vertical. It is sufficient for the suction channel to have a vertical element. That is, it is sufficient that the liquid passes upwardly through the opening area into which the gas flows, and then the liquid flows to the outlet of the suction channel leading to one of the outlet pipes 44 and 45.

  The splitter vessel 31 of FIGS. 3A, 3B, and 3C is a cylindrical vessel having an upper end close to an ellipse, and is provided horizontally. However, the separator or vessel of the present invention may have any shape and geometry. Examples of vessel shape and geometry include a vertical cylindrical vessel, a spherical vessel, a box vessel with a rectangular cross-section, and the like.

  As shown in FIG. 3, the inflow stream and the outflow stream flow in and out through the upper wall portion of the vessel 31. However, the inflow stream and the outflow stream may flow in and out through other wall portions such as a bottom wall portion or a side wall portion.

  An improved splitter of the present invention is shown in FIGS. 6A, 6B and 6C. The splitter 80 consists of a vertical cylindrical vessel. In such a splitter, the inflow stream 88 flows from the side wall of the vessel 81 through the pipe 87. A vertical splash plate 86 is provided downstream of the inlet into which the incoming stream 88 flows. The splitter has three effluent streams 91, 92 and 85. The outflow stream 91 flows out from the upper part of the vessel 31 through the outflow pipe 99. The outflow pipe 99 is connected to the suction channel 82 so that leakage does not occur. The suction channel 82 has a circular cross section and is tapered such that the cross section of the channel decreases downward. The suction channel 82 is provided with four slots 94 vertically. The bottom of the suction channel 82 is opened to allow liquid to flow. Outflow stream 92 flows out of the side of vessel 31 through outflow pipe 98. A 90 ° bend 97 is used, and an outflow pipe 98 is connected to the suction channel 83 so that leakage does not occur. The suction channel 83 has a square cross section. The suction channel 83 is provided with a V-shaped slot 93. The bottom of the suction channel 83 is open to allow liquid to flow. Outflow stream 85 flows out from the bottom of vessel 31 via outflow pipe 100. A 180 ° bend 96 is used, and the outflow pipe 100 is connected to the suction channel 84 so that leakage does not occur. The suction channel 84 has a circular cross section and is provided with a square opening 95. Since the bottom of the suction channel 84 is closed to prevent liquid flow, all liquid will flow through the square opening 95.

  During operation (or operation), the two-phase inflow stream 88 flows into the vessel 81 via the pipe 87. Such a two-phase jet impinges on the splash plate 86, thereby reducing the high velocity of the stream and causing some phase separation. In the vessel 81, the liquid phase 90 and the gas phase 89 are separated. The liquid phase is collected at the bottom of the vessel while the gas phase is collected at the top of the vessel. The gas flows in through openings 94, 93 and 95 provided on the sides of the suction channels 82, 83 and 84, respectively. Since the gas flows through the opening in this manner, a pressure drop occurs from the outside of the suction channel toward the inside of the suction channel, and the liquid is sucked into the suction channel. The liquid 90 flows in from the opened lower ends of the suction channels 82 and 83, or flows in from the openings 94, 93, and 95 located below the liquid level in the vessel 81. In the suction channel, the liquid and the gas are mixed to obtain a two-phase mixture. Then, the two-phase mixture flowing in the suction channel is discharged from the vessel 81 through the outflow pipes 98, 99 and 100.

  The splitting performance of the present invention quantified as% DVLR (defined by equation (2)) will be reduced in applications where the ratio of gas to liquid is high. In applications where the ratio of gas to liquid is high, the splitting performance of the present invention can be significantly improved by providing an internal in the suction channel to increase the pressure drop of the two-phase flow in the suction channel. An example of improving the splitting performance by increasing the pressure drop by internal is to use one or more orifices in the suction channel. Note that the use of internals in the suction channel will affect the two-phase flow pattern of the suction channel. For example, using an orifice can avoid undesirable slag flow. Incidentally, when a slag flow occurs, liquid slag and gas pockets periodically flow in the suction channel. The internal suction channel not only improves splitting performance for applications with a high gas to liquid ratio, but also somewhat improves splitting performance for applications with a lower gas to liquid ratio. Will be. Incidentally, for example, the splitters 51 and 71 shown in FIGS. 4 and 5, respectively, are splitters in which an internal for improving the division performance is not included in the suction channel.

  The splitters 30, 51, 71 and 80 shown in FIGS. 3A, 3B, 3C, 4, 5, 6, 6A, 6B and 6C all have separate separators or vessels. However, the present invention may be used integrally with other process equipment such as shell and tube heat exchangers and chemical reactors.

  7A and 7B show an example of the splitter of the present invention integrated with a chemical trickle bed 110. FIG. 7A shows the bottom of the trickle bed. A cylindrical pressure shell 101 having a hemispherical head 102 is filled with catalyst particles 103, and the catalyst particles 103 are supported by a catalyst support grid or screen 104. The catalyst support grid / screen is designed so that gases and liquids pass through the screen while preventing catalyst particles from passing through the screen. Below the catalyst support grid / screen, two vertical suction channels 107 are arranged. Each suction channel is provided with eight slots 108. The suction channel is also provided with an internal to increase the pressure drop in the suction channel. Such an internal is composed of four orifices 109, 110, 111 and 112 respectively provided in the suction channel. Each suction channel 107 is connected to the outflow nozzle 105 by a channel 106 provided with a bend so that no leakage occurs.

  During operation (or operation), gas and liquid simultaneously flow downward through the bed of catalyst particles 103 and the catalyst support grid / screen 104. Below the catalyst support grid / screen 104, a space for separating the liquid phase 113 and the gas phase 114 is provided. The liquid phase 113 is collected at the bottom of the reactor. The gas flows from a part of the slot 108 above the liquid level. As the gas flows in from the slot, a pressure drop occurs from the outside of the suction channel toward the inside of the suction channel, and the liquid is sucked into the suction channel. The liquid 113 flows from the opening of the lower orifice 112 or flows from a part of the slot 108 below the liquid level. Liquid and gas are mixed in the suction channel. The resulting mixture will flow through the suction channel and orifice and then be discharged from the reactor 110 via the nozzle 105.

FIG. 8 shows an example of a splitter of the present invention integrated with a shell and tube heat exchanger 120. A shell and tube heat exchanger consists of the following elements:
A head 122 provided with a cover plate 128, a tube-side inlet nozzle 129 and a tube-side outlet nozzle 130;
A shell 121 provided with an inlet nozzle 131 and two outlet nozzles 125
A U-tube bundle consisting of a U-tube 124, a tube sheet 135 and 13 flow baffles 132.

  Space for the two-phase splitter of the present invention (space on the side of the shell downstream of the last flow baffle, downstream of the 180 ° vent of the U-tube 124) In order to provide space, the length of the shell 121 is slightly longer than in the case of a normal heat exchanger design. The splitter consists of two substantially vertical suction channels 126 with holes 127 in the wall. The bottom of the suction channel 127 is open so that liquid can flow.

  During operation (or operation), the fluid supplied to the tube side flows into the heat exchanger from the nozzle 129, flows so as to pass through the U-shaped tube, and is then discharged from the heat exchanger through the nozzle 130. . The fluid supplied to the shell side flows from the nozzle 131 into the heat exchanger. The fluid provided on the side of this shell may be a single phase stream or a two phase stream. The fluid provided to the shell side flows outside the U-tube. Since the flow baffle 132 forms several orthogonal flow sections, the fluid provided to the shell side will flow in the flow baffle 132 in a direction orthogonal to the tube. After passing through the last provided flow baffle, the two-phase stream flows into the separation space where the liquid 133 and the gas 134 are separated. The liquid phase 133 is collected at the bottom of the shell 121. The gas 134 flows into the suction channel through a part of the hole 127 located above the liquid level. As gas flows from such holes, a pressure drop occurs from the outside of the suction channel toward the inside of the suction channel, and liquid is sucked into the suction channel. The liquid 133 flows from the open bottom end of the suction channel 126, or flows from a part of the hole 127 located below the liquid level. In the suction channel, the liquid and the gas are mixed. The resulting mixture will flow through the suction channel and orifice and then be exhausted from the heat exchanger 120 via the nozzle 125.

  In the example shown in FIGS. 4 and 5, the two-phase inflow stream is divided into the downstream piping system and the process equipment provided in parallel. However, the present invention may be used in process equipment, in which case gas and liquid can be evenly distributed to parallel passages provided in the equipment. For example, the invention can be used in the inflow header (or inlet header) of a heat exchanger or air cooler, in which case gas and liquid are evenly distributed to parallel tubes provided in the heat exchanger. Can be distributed.

  In all examples of the invention described herein, only one suction channel is connected to one outflow pipe. However, one or more suction channels may be provided for one effluent stream. When one or more suction channels are provided for one effluent stream, the suction channels provided in the effluent stream are not necessarily the same. For example, in a splitter designed to split a two-phase inlet stream into two outlet streams, all three suction channels are connected to the first outlet stream and another two suction channels are connected to the second outlet stream. Thus, a total of five different sized suction channels may be used. In some cases, splitting performance may be improved by using different suction channels for the same effluent stream.

  In all examples of the application of the invention described herein, only one incoming stream is provided to the splitter. However, there may be one or more inflow streams provided to the separation vessel of the splitter. Such an inflow stream may also use a single phase inflow that provides only gas or a single phase inflow that provides only liquid.

  Although the splitter of the present invention has the ability to separate a two-phase gas-liquid mixture, it may also be used for other applications. For example, to separate a two-phase mixture of immiscible liquids (eg, a two-phase mixture of a hydrocarbon liquid phase and an aqueous liquid phase) into two or more effluent streams, each with an oil / water ratio as desired. The splitter of the present invention can be used.

  In general, the following are relevant to the present invention:

  The present invention relates to a splitting device that splits a two-phase inflow stream consisting of a light phase and a heavy phase into two or more effluent streams each having a desired light phase / heavy phase ratio. The dividing device is composed of one or more separation vessels or separation containers. In the vessel, the light and heavy phases are partially or completely separated. The vessel is provided with at least two hollow suction channels having a lower end and an open upper end.

  The plurality of openings provided in the side portions of the respective suction channels are provided at at least different heights between the lower end portion and the upper end portion. The lower end of such a channel is immersed in the heavy phase while the open upper end of the suction channel is immersed in the light phase. The opened upper end of the suction channel is connected to the downstream system by the flow channel so that no leakage occurs.

  In operation, the suction channel must have a vertical element so that at least part of the opening area is located above the interface level. In operation, since the light phase flows into the suction channel from a part of the opening region located above the interface level, a pressure drop occurs from the outside of the suction channel toward the inside of the suction channel. Therefore, due to this pressure drop, the heavy phase will be sucked into the suction channel through the open lower end and the opening located below the interface level. In the suction channel, the heavy phase and the light phase are mixed. The two-phase stream will flow through the suction channel and the flow channel to the downstream system.

  An internal or flow restriction may be provided inside the suction channel to increase the pressure drop and change the two-phase flow mechanism in the suction channel.

  The internal may be an orifice with a circular flow opening.

  The bottom of the suction channel may be closed, in which case all the heavy phases will flow from the suction level side openings located below the interface level.

  The vessel or container may be used for other process equipment used for other purposes such as performing chemical reactions or heat exchange in addition to the purpose of splitting the stream.

  The downstream system may be a parallel flow tube of equipment in which a splitter is integrated.

  Further, the downstream system may be a processing facility including piping, an instrumentation device, and equipment.

  The suction channel may have a circular cross section.

  The opening provided in the side of the suction channel may be a circular hole or a rectangular slot.

  The vertical distance from the bottom of the suction channel to the highest opening is preferably 100 mm to 1500 mm.

  The no-slip two-phase flow velocity at the upper end of the suction channel is preferably 0.5 m / s to 15 m / s in at least one operation mode.

  One or more suction channels may be connected to each downstream system.

  The device of the present invention can be advantageously used to split a two-phase gas / liquid mixture and supply it to a parallel heat exchanger.

  The device of the present invention can be advantageously used to split a two-phase gas / liquid mixture and supply it to a parallel furnace tube.

  The device of the present invention can be advantageously used to split a two-phase gas / liquid mixture and supply it to a parallel chemical reactor.

  The device of the present invention can be advantageously used to split a two-phase gas / liquid mixture and feed it to a parallel air cooler.

  The device of the present invention can be advantageously used to distribute gases and liquids to parallel heat exchange tubes or heat exchange channels provided in a two-phase heat exchanger or air cooler.

FIG. 1 represents the prior art. FIG. 1 is an isometric view of a piping system using a symmetric piping split, where the incoming stream is divided into four outgoing streams by using three standard tees. FIG. 2 represents the prior art. FIG. 2 is a process flow diagram of a gas / liquid splitter with instrumentation used to split the incoming stream into three outgoing streams. FIG. 3A represents one embodiment of the present invention and is a side view of the embodiment taken along line AA. FIG. 3B represents one embodiment of the present invention and is a side view of the embodiment taken along line BB. FIG. 3C represents one embodiment of the present invention and is a side view of the embodiment taken along line CC. FIG. 4 is a process flow diagram illustrating an example of the application of the splitter of the present invention. The splitter is used to split the two-phase stream into three and send it to three parallel systems consisting of a heat exchanger, instrumentation and furnace tube. FIG. 5 is a process flow diagram illustrating an example of the application of the splitter of the present invention. The splitter splits the two-phase stream into two and sends them to the two trickle bed reactors. FIG. 6A represents a further aspect of the present invention and an alternative suction channel design (cross-sectional view taken along line AA). FIG. 6B represents a further embodiment of the present invention and an alternative suction channel design (side view taken along line BB). FIG. 6C represents a further aspect of the present invention and an alternative suction channel design (side view taken along line CC). FIG. 7A represents a further embodiment of the invention, showing a splitter integrated with the chemical reactor (side view of the bottom of the chemical reactor). FIG. 7B represents a further embodiment of the present invention, showing a splitter integrated with a chemical reactor (cross-sectional view of the suction channel of FIG. 7A taken along line AA). FIG. 8 represents a further embodiment of the present invention, showing a splitter integrated with a shell and tube heat exchanger (side view of heat exchanger and splitter).

Claims (18)

To divide one or more two-phase inflow streams consisting of a gas light phase fluid and a liquid heavy phase fluid into two or more two-phase outflow streams each having a desired light phase / heavy phase ratio. Stream splitting device of
A phase separation vessel or phase separation container, and comprising two or more suction channels or conduits provided at least one for each of the effluent streams;
The phase separation vessel or phase separation container is
One or more inlet stream inlets for the inlet stream,
A heavy phase collection region, and a light phase collection region located at a higher level than the heavy phase collection region, and the suction channel or suction conduit comprises:
-At least one heavy phase inlet in communication with the heavy phase collection area;
At least one light phase inlet in communication with the light phase collection area and at a higher level than the at least one heavy phase inlet; and at least one effluent stream in communication with an effluent stream flow conduit downstream of the device Having an exit
A stream splitting device, wherein the at least one light phase inlet is disposed between the at least one heavy phase inlet and the at least one effluent stream outlet.   The suction conduit consists of an elongate tubular element defined by a wall provided with one or more openings, said tubular element being for example a pipe or duct having a circular or rectangular cross section. The device according to 1.   The device of claim 2, wherein the lower end of the tubular element is open.   The device according to claim 2 or 3, wherein the shape of the one or more openings is a shape selected from the group consisting of a circle, an ellipse, an oval, a rectangle and a triangle.   The device according to claim 1, wherein the light phase inlet and the heavy phase inlet are composed of a single opening.   The device of claim 5, wherein the width of the slot increases in a direction toward the outlet stream outlet.   7. A device according to any one of the preceding claims, wherein a flow restricting means is provided in the suction conduit so that the light phase pressure drop increases at the light phase inlet.   The flow restricting means comprises a transverse plate provided with one or more orifices such that the flow in the suction conduit is directed to the one or more orifices; The device according to claim 7.   9. A device according to any one of the preceding claims, wherein a flow buffering means is provided near the inlet stream inlet such that the incoming stream impinges on the flow buffering means.   The vertical distance between the bottom of the one or more heavy phase inlets and the top of the one or more light phase inlets is between 100 mm and 1500 mm. The device described.   An apparatus in which physical processing or chemical processing using a two-phase stream is performed, and a stream dividing device according to any one of claims 1 to 9, wherein the stream dividing device and an inlet of the apparatus or A processing facility that is connected to the outlet.   12. A treatment facility according to claim 11, wherein the apparatus comprises a furnace comprising a set of furnace tubes connected to the effluent stream outlet.   The processing equipment of claim 11, wherein the apparatus comprises a parallel heat exchanger connected to the effluent stream outlet.   The processing facility of claim 11, wherein the apparatus comprises a parallel chemical reactor connected to the effluent stream outlet.   12. A treatment facility according to claim 11, wherein the apparatus comprises a parallel air cooler connected to the effluent stream outlet. A reactor comprising the stream splitting device according to claim 1,
A reactor comprising an outer shell, wherein the phase separation vessel is disposed within the outer shell.   A heat exchanger comprising the stream splitting device according to any one of claims 1 to 9, comprising an outer shell, wherein a phase separation vessel is disposed in the outer shell. . To divide one or more two-phase inflow streams consisting of a gas light phase fluid and a liquid heavy phase fluid into two or more two-phase outflow streams each having a desired light phase / heavy phase ratio. The method of
-At least partially dividing the incoming stream into a heavy phase portion located in the heavy phase region below the phase boundary surface and a light phase portion located in the light phase region above the phase boundary surface; and By mixing the heavy phase fluid from the heavy phase portion with the light phase fluid from the light phase portion at two or more points in the light phase region, Forming a phase effluent stream.

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