JP2002228142A - Variable pressure steam tracing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable pressure steam tracing apparatus wherein temperature of trace vapor can be set to be that matched to flow-point temperature of a fluid flowing through piping, and carbonization of a fluid in the piping due to excess temperature rise and abnormal rise of internal pressure can be prevented from happening. SOLUTION: An opening adjustment instruction 22 is outputted from a controller 23 to a pressure adjustment valve 21 based upon pressure 19 of trace vapor detected by a pressure meter 20 such that temperature of the trace vapor becomes that matched to a flow-point of a fluid flowing in the piping 13. Hereby, pressure control for the trace vapor is achieved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable-pressure steam tracing apparatus.

[0002]

2. Description of the Related Art FIG. 2 shows an example of a fuel supply system of an oil fired boiler. The fuel supply system of the oil fired boiler guides fuel stored in a service tank 1 to a burner 3 of the boiler 2. And a return line 5 for returning the fuel flowing through the supply line 4 to the service tank 1.
An injection pump 6 for pumping fuel is provided, an individual shut-off valve 7 is provided on the inlet side of each of the burners 3, a switching valve 8 is provided in the middle of the return line 5, and the service tank 1 is provided with: The storage tank 12 is connected via a replenishment line 11 provided with a supply valve 9 and a transfer pump 10 on the way.

When the fuel is preheated before the burner 3 is ignited, such as when the boiler 2 is started, first, the switching valve 8 in the return line 5 is opened and the shut-off valves 7 are closed. The fuel stored in the service tank 1 is
The fuel pumped by the operation of the fuel pump 6 is heated by a heater (not shown), returned from the supply line 4 to the service tank 1 via the return line 5, and circulated.

When the temperature of the fuel circulated between the supply line 4 and the return line 5 reaches a preset temperature, the switching valve 8 is closed and the shut-off valves 7 are opened, and the corresponding valves are opened. Fuel is injected from the burner 3 into the furnace of the boiler 2 and ignited by the burner 3 to perform combustion.

The service tank 1 is provided with a storage tank 12 by operating a transfer pump 10 if necessary.
Is supplied through the replenishment line 11.

By the way, as shown in FIG. 3, a steam pipe 15 into which trace steam from a trace steam source 14 is introduced extends along a pipe 13 constituting the replenishment line 11. A so-called steam tracing device is provided, which heats the pipe 13 by introducing trace steam from 14, and the steam tracing device heats and fluidizes fuel as a fluid. In recent years, vacuum residue oil such as asphalt obtained as a residue during petroleum refining is sometimes used as a fuel. Incidentally, in FIG.
Is a steam trap for discharging condensed water from the steam pipe 15 as drain.

[0007] The vacuum residue has a pour point temperature of about 2
It is very high, about 20 [° C], and when the boiler 2 is stopped,
In order to prevent solidification inside the pipe 13, heavy oil or the like is supplied into the pipe 13 from a purge line 17 indicated by a virtual line in FIG. 2, and waste oil is supplied from the replenishment line 11 through the supply line 4 and the return line 5. By discharging from line 18,
Purging the fuel such as reduced pressure residual oil remaining inside the pipe 13 is performed.

Here, the pour point temperature of heavy oil or the like used for purging the fuel such as the vacuum residue oil or the like is about 50 ° C., but by design, trace steam is generated based on a fluid having a high pour point temperature. As described above, when a fluid such as heavy oil having a pour point temperature lower than that of a fuel such as a vacuum residue oil flows as described above, in the conventional case, ON-OFF of the trace steam is performed.
Temperature control.

[0009]

However, when the trace steam is selected on the basis of a fluid having a high pour point temperature, as described above, when the fluid having a low pour point temperature flows, the ON- If the temperature control is performed with the temperature OFF, the temperature rise rate is large, and there is a possibility that carbonization or an abnormal increase in the internal pressure due to excessive temperature rise of fluid such as heavy oil in the pipe 13 may occur.

In the present invention, in view of such circumstances, the temperature of trace steam can be set to a temperature corresponding to the pour point temperature of the fluid flowing through the pipe. It is an object of the present invention to provide a variable-pressure steam tracing device capable of preventing an abnormal rise in the temperature.

[0011]

According to the present invention, a steam pipe is provided along a pipe through which a plurality of fluids having different pour point temperatures are switched and circulated, and trace steam from a trace steam source is introduced into the steam pipe. A variable-pressure steam tracing device adapted to heat piping, a pressure gauge for detecting the pressure of trace steam supplied to the steam pipe, and a pressure control valve for adjusting the pressure of trace steam supplied to the steam pipe And, so that the temperature of the trace steam becomes a temperature corresponding to the pour point temperature of the fluid flowing through the pipe, output an opening degree adjustment command to the pressure control valve based on the pressure of the trace steam detected by the pressure gauge,
And a controller for controlling the pressure of trace steam.

According to the above means, the following effects can be obtained.

When a fluid having a high pour point temperature flows through the pipe, an opening degree adjustment command is output from the controller to the pressure adjustment valve based on the pressure of the trace steam detected by the pressure gauge.
The pressure of the trace steam is controlled, and the temperature of the trace steam is adjusted to a temperature suitable for the fluid having a high pour point temperature flowing through the pipe.

On the other hand, when a fluid having a low pour point temperature flows through the pipe, an opening adjustment command is output from the controller to the pressure control valve based on the pressure of the trace steam detected by the pressure gauge, and the trace The steam pressure is controlled, and the temperature of the trace steam is adjusted to a temperature suitable for the fluid having a low pour point temperature flowing through the pipe.

As a result, even when the trace steam is selected based on the fluid having a high pour point temperature, when the fluid having a low pour point temperature flows, the ON-O of the trace steam is performed.
Rather than performing temperature control with the FF, temperature control by trace steam pressure control becomes possible, avoiding an increase in temperature rise rate, and causing excessive temperature rise of the fluid inside the piping, resulting in carbonization and abnormal internal pressure rise. Disappears.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an example of an embodiment of the present invention. In the figure, the parts denoted by the same reference numerals as those in FIGS. 2 and 3 represent the same parts, and the basic structure is shown in FIGS. 3 is the same as the conventional one shown in FIG. 3, but is characterized by a pressure gauge 20 for detecting the pressure 19 of the trace steam supplied to the steam pipe 15 as shown in FIG. Tube 1
And a pressure control valve 21 for adjusting the pressure 19 of the trace steam supplied to 5, and the pressure gauge 20 detects the temperature of the trace steam to be a temperature corresponding to the pour point temperature of the fluid flowing through the pipe 13. This is characterized in that an opening degree control command 22 is output to the pressure control valve 21 based on the pressure 19 of the trace steam, and a controller 23 for controlling the pressure of the trace steam is additionally provided.

Next, the operation of the illustrated example will be described.

During normal operation, the fuel such as vacuum residual oil is supplied to the service tank 1 from the storage tank 12 by the operation of the transfer pump 10 as necessary.
When the replenishment is performed via the pressure gauge 20, the opening degree control command 22 is output from the controller 23 to the pressure control valve 21 based on the pressure 19 of the trace vapor detected by the pressure gauge 20, and the pressure of the trace vapor is set to, for example, 15 [Kgf / m ² ] (≒ 15 × 9.8
[Pa]), and the temperature of the trace steam is
The temperature is adjusted to a temperature corresponding to the pour point temperature (about 220 [° C.]) of the fuel such as the vacuum residue oil which is circulated through the tank.

On the other hand, when the boiler 2 is stopped, in order to prevent the solidification of fuel such as reduced pressure residual oil inside the pipe 13, FIG.
Medium, a fluid such as heavy oil is supplied into the pipe 13 from the purge line 17 indicated by the phantom line, and discharged from the waste oil line 18 through the supply line 4 and the return line 5 from the replenishment line 11 so that When purging the remaining fuel such as reduced pressure residual oil, the controller 23 outputs an opening control command 22 to the pressure control valve 21 based on the pressure 19 of the trace steam detected by the pressure gauge 20, Is 5 [kgf / m ² ] (≒ 5 × 9.8 [P
a)), and the temperature of the trace steam is adjusted to the pour point temperature of a fluid such as heavy oil flowing through the pipe 13 (about 50 [° C.]).
Temperature).

As a result, even when a trace steam is selected based on a fluid having a high pour point temperature (such as reduced pressure residual oil), when a fluid having a low pour point temperature (such as heavy oil) flows, Rather than performing temperature control by ON / OFF of the trace steam, temperature control by pressure control of the trace steam becomes possible, so that the temperature rise rate is prevented from increasing, and excessive temperature rise of fluid such as heavy oil inside the pipe 13 is performed. This prevents carbonization and abnormal increase in internal pressure.

In this way, the temperature of the trace steam is
Can be set to a temperature corresponding to the pour point temperature of the fluid flowing through the pipe 13, and it is possible to prevent carbonization and abnormal increase in internal pressure due to excessive temperature rise of fluid such as heavy oil inside the pipe 13.

The variable-pressure steam tracing apparatus of the present invention is not limited to the above-described illustrated example, and various changes can be made without departing from the scope of the present invention.

[0024]

As described above, according to the variable pressure steam tracing apparatus of the present invention, the temperature of the trace steam can be adjusted to the temperature corresponding to the pour point temperature of the fluid flowing through the pipe, An excellent effect of preventing carbonization and abnormal increase in internal pressure due to excessive temperature rise of the fluid in the above can be achieved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an example of an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram illustrating an example of a fuel supply system of a boiler provided with a steam trace device.

FIG. 3 is a schematic configuration diagram of an example of a conventional steam trace device.

[Explanation of symbols]

 13 piping 14 trace steam source 15 steam pipe 19 pressure 20 pressure gauge 21 pressure control valve 22 opening control command 23 controller

Claims (1)

[Claims] 1. A steam pipe is arranged along a pipe through which a plurality of fluids having different pour point temperatures are switched and circulated, and trace steam from a trace steam source is introduced into the steam pipe to heat the pipe. A variable-pressure steam tracing device, comprising: a pressure gauge for detecting the pressure of trace steam supplied to a steam pipe; a pressure regulating valve for regulating the pressure of trace steam supplied to a steam pipe; Controller that outputs an opening adjustment command to the pressure control valve based on the pressure of the trace steam detected by the pressure gauge so as to have a temperature corresponding to the pour point temperature of the fluid circulated through the controller, and controls the pressure of the trace steam. And a variable-pressure steam tracing device.