JP4467376B2 - Steam tracer - Google Patents

Description

  The present invention relates to a steam trace device for heating a pipe such as a fuel transport pipe.

  2. Description of the Related Art Conventionally, there is known a steam tracing device that prevents a transportation fuel (for example, crude oil) from clumping by placing a steam pipe along a pipe such as an outdoor fuel transport pipe and heating the pipe to keep it at an appropriate temperature. .

  The structure of this type of general steam tracing apparatus is shown in FIG. In the steam tracing device shown in FIG. 2, the steam pipe downstream from the steam supply valve 4 is divided into two, and one steam pipe 2 is arranged in the downstream (fuel supply) direction of the pipe 1 for transporting fuel such as crude oil. The steam trace device is a two-line type steam trace device in which the steam pipes 3 are arranged along the pipes 1 in the upstream direction of the pipes 1 and the corresponding portions of the pipes 1 are heated. Compared with the 1-line system, the 2-line system has the advantage that the number of installed steam supply valves and the supply steam system (line) can be reduced and the heating control can be performed efficiently, so that the equipment cost can be reduced.

  Steam (for example, auxiliary steam) from a steam supply source (for example, in-house boiler) (not shown) is supplied to the steam pipes 2 and 3 by opening the steam supply valve 4, and the steam passes through the steam pipes 2 and 3. As a result, the pipe temperature of the corresponding part rises. The steam passing through the steam pipes 2 and 3 is changed to drain such as condensate or condensed hot water and discharged from the drain traps 7 and 8.

  The drain traps 7 and 8 have a simple mechanism (with a float (valve element) that moves up and down according to the fluctuation of the liquid level inside, and when the drain accumulates, the float floats to discharge the drain). Float type drain traps that are easy to maintain are used.

  The temperature detectors 5 and 6 are installed at predetermined positions of the pipes 1 related to the steam pipes 2 and 3, detect the temperature of the corresponding part, and output the result to the control unit 9. The controller 9 recognizes the lower one of the detected temperatures as the current pipe temperature, and performs opening / closing control of the steam supply valve so as to reduce the difference between the temperature and the appropriate temperature (for example, 60 ° C.). Specifically, if the pipe temperature is lower than the appropriate temperature, the steam supply valve is controlled to be “open” to supply steam, and if higher than the appropriate temperature, the steam is controlled to be “closed” to shut off the supplied steam.

  As shown in FIG. 2, when the pipe 1 is arranged so as to be substantially linear and parallel to the ground within the range heated by the steam tracing device, it takes over the drain traps 7 and 8. The drain inflow pressure is substantially equal (pressure loss from the steam supply valve 4 to the drain traps 2 and 3 is substantially equal), and the amount of steam passing through the steam pipes 2 and 3 is substantially the same at the time of steam supply. The heat exchange with the corresponding part of the pipe 1 related to is also performed substantially equally. As described above, the opening and closing control of the steam supply valve 4 is performed according to the detected temperature, and the supply and shut-off of the steam are repeated as appropriate, so that the corresponding part of the pipe 1 where the steam pipes 2 and 3 are disposed is set to the appropriate (normal) temperature. Can be maintained.

  However, in the steam tracing device having the above-described configuration, there is a possibility that the pipe temperature cannot be properly maintained when the difference is widened in the pressure loss of the steam pipes 2 and 3.

  An example thereof will be described with reference to FIG. The pipe 1 shown in FIG. 3 includes a part (rising part) protruding partly in the upper direction on the downstream side. Therefore, a similar rising portion is included in the steam pipe 2 arranged along this.

  The pressure loss of the steam pipe 2 including the rising portion is larger than the pressure loss of the substantially horizontal steam pipe 3, and stays in the steam pipe 2 even when the steam is supplied (steam supply valve 4 is open). It becomes difficult to drain the drain that is. Therefore, compared with the steam pipe 3, the steam passage amount of the steam pipe 2 is reduced, and as a result, the heat exchange property is also deteriorated, and the temperature increase rate of the corresponding part of the pipe 1 is also deteriorated.

  In this case, the control unit 9 described above controls the steam supply valve 4 on the basis of the detected temperature (temperature lower side) related to the steam pipe 2. That is, the steam supply valve 4 is opened and steam is supplied until the detected temperature related to the steam pipe 2 reaches an appropriate temperature (for example, 60 ° C.). On the other hand, the detected temperature related to the steam pipe 3 with a low pressure loss and a good temperature rise rate reaches the appropriate temperature before the detected temperature related to the steam pipe 2 reaches the appropriate temperature. ) Continues, excess steam continues to be supplied to the steam pipe 3.

  As a result, the detected temperature related to the steam pipe 3 continues to rise even if it exceeds 60 ° C., and reaches a considerably high temperature (for example, about 90 ° C.) when the detected temperature related to the steam pipe 2 reaches an appropriate temperature. There is a risk that.

  The present invention has been made to solve the above-described conventional problems, and is capable of heating to a desired temperature even in a pipe including a portion that causes pressure loss such as a rising portion. The purpose is to provide.

In the steam trace device according to the present invention, the steam pipes separated into two lines via the steam supply valve are arranged along the pipes in the upstream direction and the downstream direction of the pipes, respectively. A temperature detector is installed at a predetermined position of the pipe, and the lower temperature detected by each temperature detector is recognized as the current pipe temperature, and the difference between the current pipe temperature and the appropriate temperature is reduced. in steam tracer that controls the opening and closing of the steam supply valve as said of the steam tube of the two lines, the larger drain occurring in the steam pipe of the pressure loss than the other hand is, the drain trap temperature adjustable the discharged Rutotomoni, drain occurring in the steam pipe towards the pressure loss is less than the other, is configured to be discharged by the float of the drain trap, Furthermore, when the drain that flows into the temperature-adjustable drain trap is a temperature that is equal to or lower than the discharge drain temperature that is set in the temperature-adjustable drain trap, the drain is always discharged regardless of the inflow amount. It characterized that you control the drain trap of the temperature adjustable.

The temperature control type (temperature control type) drain trap has a structure that operates the discharge valve and discharges the accumulated drain according to the drain temperature. Even if it exists, it can discharge | emit, without making a drain stay. Therefore, when steam is supplied (when the steam supply valve is “open”), it is possible to make the amount of new steam passed substantially the same as the steam pipe of the other line with less pressure loss. Thereby, the temperature increase speed of the piping corresponding part which concerns on each steam pipe can also be controlled substantially the same, and each applicable part can be controlled to appropriate (normal) temperature.

  Further, in consideration of maintainability and cost, the drain generated in the steam pipe having the smaller pressure loss than the other of the steam pipes of the two lines is discharged by a float type drain trap. It is preferable to do this.

  As described above, the steam tracing device of the present invention can heat and maintain a desired temperature even if the piping portion to be heated includes a special shape such as a rising portion. it can.

  Hereinafter, an embodiment of a steam tracing device according to the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram illustrating an application example of the steam tracing apparatus according to the present embodiment. In FIG. 1, a pipe 1 is a pipe installed outdoors for transporting fuel (crude oil in this embodiment) consumed in a power plant. In the pipe 1, steam pipes 2, 3 made of copper or the like separated into two lines in the downstream line from the steam supply valve 4 are connected to the pipe 1 in the downstream direction (fuel supply direction) and the upstream direction of the pipe 1, respectively. They are arranged in contact with each other.

  The steam supply valve 4 opens and closes based on an open / close control signal from the control unit 9, and in the case of “open”, steam (for example, auxiliary steam) sent from a steam supply source (for example, an in-house boiler) is supplied to the steam pipe 2. 3 and when it is “closed”, the supply is shut off.

  Drain traps 10 and 8 are connected to the end portions of the steam pipes 2 and 3, respectively. The drain trap is a device that automatically discharges condensate, hot water, and other drains generated in the steam pipe. As the drain is discharged from the drain trap, new steam can pass through the steam pipe. Therefore, when the drain is constantly discharged from the drain trap, the heat exchange between the steam and the pipes becomes frequent, and the pipe temperature can be raised.

  Generally, there are two types of drain traps, a float type and a temperature control (temperature adjustment) type, depending on the difference in drain discharge mechanism. In a conventional steam trace apparatus of this type, a float type is used for both of the two lines of steam pipes. The steam trace device of the present invention uses a temperature-controlled drain trap in the steam pipe having the larger pressure loss (pressure at which the outlet pressure of the steam supply valve (steam supply pressure) drops to the drain trap inlet). It has features that are not available in the past.

  Returning to FIG. 1 and continuing the description, a rising portion is included on the downstream side of the pipe 1, and the rising portion is similarly included in the steam pipe 2 disposed corresponding thereto. The loss is larger than that of the steam pipe 3. In the steam trace apparatus according to the present embodiment, a temperature-controlled drain trap 10 is used as the drain trap of the steam pipe 3. The other points are the same as those of the conventional steam tracing apparatus (FIGS. 2 and 3), and the same reference numerals are given to the common parts with FIGS. 2 and 3, and the description is omitted.

  Hereinafter, the heating operation of the pipe by the steam tracing device according to the present embodiment will be described.

  Information about the pipe temperature detected by the temperature detectors 5 and 6 is sent to the control unit 9. The controller 9 regards the lower one of the detected temperatures as the temperature to be adjusted (target temperature), and this temperature and a predetermined appropriate temperature (in this embodiment, 60 ° C. (crude point of crude oil (about 35 ° C.)). ) + 25 ° C.) The steam supply valve 4 is controlled so as to reduce the difference from this. Specifically, when the target temperature does not reach 60 ° C., an “open” command signal is output to the steam control valve 4, and the steam control valve 4 is opened in response to this, and steam from the steam supply source is steamed. Supply to tubes 2 and 3. On the other hand, when the target temperature exceeds 60 ° C., a “close” command signal is output to the steam control valve 4, whereby the steam control valve 4 is closed and the steam supply is shut off.

  When the steam supply valve 4 is opened and steam is supplied, the drain staying in the steam pipe 3 with a small pressure loss flows into the drain trap 8 and is discharged to the outside due to the supply pressure. Thereby, a new vapor | steam can pass the inside of the steam pipe 3, and the temperature of the applicable site | part of the piping 1 is raised in connection with it.

  On the other hand, in the steam pipe 2, the drain temperature of the drain trap 10, which is a temperature control type, is set in advance, and if the inflow drain temperature is lower than this, the drain is discharged even if the inflow amount is small. The discharge drain temperature is calculated so that the pipe temperature is set to an appropriate temperature (60 ° C.), and when steam is supplied (that is, when the pipe temperature does not reach 60 ° C.), the drain flowing into the drain trap 10 is discharged. Since this temperature is equal to or lower than the discharge drain temperature, it is always discharged regardless of the amount of inflow. Therefore, at the time of steam supply, like the steam pipe 3, new steam passes through the steam pipe 2, and the temperature of the corresponding part of the pipe 1 rises.

  Thus, at the time of steam supply, substantially the same amount of steam can be passed through the steam pipes 2 and 3, and the temperature of the corresponding part of the pipe 1 relating to each of the steam pipes 2 and 3 can be set to an appropriate temperature in substantially the same time. The temperature can be raised to (60 ° C.).

  As described above, according to the steam tracing device of the present embodiment, both the shapes of the rising portions and the like are included in the piping to be heated, so that both of the two lines of steam pipes have a large pressure loss difference. It becomes possible to control the temperature rising speed of the piping related to the line substantially the same.

  The steam trace device according to the present invention is not limited to the above embodiment, and various modifications can be made without departing from the gist of the present invention.

It is a figure which shows the application aspect of the steam trace apparatus which concerns on one Embodiment of this invention. It is a figure (the 1) which shows the application aspect of the conventional steam trace apparatus. It is a figure (the 2) which shows the application aspect of the conventional steam trace apparatus.

Explanation of symbols

1 Piping 2, 3 Steam pipe 4 Steam supply valve 5, 6 Temperature detector 7, 8 Drain trap (float type)
9 Control unit 10 Drain trap (temperature control type)

Claims (2)

Steam pipes separated into two lines via a steam supply valve are arranged along the pipes in the upstream and downstream directions of the pipe, respectively, and temperature is detected at a predetermined position of the pipe related to each steam pipe. Open / close control of the steam supply valve so that the lower one of the detected temperatures of each temperature detector is recognized as the current pipe temperature, and the difference between the current pipe temperature and the appropriate temperature is reduced. In the steam trace device that performs
Of steam tube of the two lines, the larger drain occurring in the steam pipe of the pressure loss than the other hand is discharged by the drain trap temperature adjustable Rutotomoni, steam pipe towards the pressure loss is smaller than the other The drain generated in the tank is discharged by a float drain trap,
Further, when the drain flowing into the temperature-adjustable drain trap is a temperature equal to or lower than the discharge drain temperature set in the temperature-adjustable drain trap, the drain is constantly discharged regardless of the inflow amount. A steam tracing device that controls a temperature-adjustable drain trap . The steam tracing device according to claim 1, wherein the steam pipe having a large pressure loss has a bent portion .

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