JPH0243103B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hot water boiler suitable for use when a large scale supply of hot water is required, such as in an oil field.

Conventionally, hot water boilers of this kind having various structures and types have been known, one example of which is illustrated in FIGS. 1 and 2. To briefly explain this, Fig. 1 shows a once-through type hot water boiler, and the reference numeral 1 in the figure is a water supply pipe that supplies cold water with a water supply pump 2, and the water is fed into the combustion chamber 3 through this water supply pipe 1. The cold water is heated in the combustion chamber water-cooled wall tube 4 and the convection evaporation tube 5 to become hot water, which is sent to the outside via the hot water outlet tube 6. In addition, a temperature detector 7 is arranged in the middle of this hot water outlet pipe 6,
It is configured to send a temperature signal of hot water to the controller 8. This controller 8 is
A fuel supply pipe 10 that supplies fuel to the burner 9 for combustion by injecting fuel into the combustion chamber 3.
It controls the opening and closing of a fuel control valve 11 provided in the middle of the hot water, thereby playing the role of controlling the temperature of the hot water to a desired value.

However, in such a once-through type, the metal temperature of the water-cooled wall tube 4 of the combustion chamber increases due to the low load and low heat transfer coefficient within the tube. It is necessary to increase the flow velocity in the pipe 4, enlarge the combustion chamber 4, or lower the maximum load, and furthermore, it is necessary to control the temperature of hot water using a signal from a temperature sensor 7 installed in the hot water outlet pipe 6. The disadvantages are that the detection delay is large and it is difficult to properly control the temperature.

In particular, in such a direct temperature detection method using the temperature detector 7 installed in the hot water outlet pipe 6, non-periodic heat conduction occurs through the wall of the thermometer facing into the hot water outlet pipe 6 and the wall of the thermometer protection tube. Therefore, it is unavoidable that a time delay of several seconds to several minutes usually occurs, and this time delay makes it difficult to quickly and appropriately control the hot water temperature based on the control of the amount of fuel supplied to the combustion chamber 3. It was hot.

The hot water boiler shown in FIG. 2 is of a natural circulation type, and has a pair of upper and lower hot water drums 12.
and a water drum 13, both drums 1
Cold water is circulated through a convection heat exchanger tube 5 interposed between 2 and 13 to heat it. however,
In a hot water boiler with such a structure, since the purpose is to store and supply hot water having a desired temperature in the upper hot water drum 12, there is no water surface in the upper drum and there is no water surface in the water cooling wall tube 3 of the combustion chamber. Since the water is not boiled, the circulation capacity is small, and the heat transfer coefficient inside the tube is also small.As a result, the metal temperature always tends to rise, making it necessary to lower the load or enlarge the combustion chamber 4. However, like the once-through type described above, it also had the disadvantage that it was difficult to control the temperature of the hot water.

Conventional hot water boilers of this kind are often used for small-scale applications, and minor defects can be ignored, but those for large-scale installations with a large demand for hot water, such as those used in oil fields, do not suffer from such problems. This is unacceptable and it is desirable that some kind of countermeasure be taken.

The present invention has been made in view of the above circumstances, and the upper drum is configured as a brackish water drum, and a water surface is clearly provided in the brackish water drum so that the effect as a natural circulation boiler is exhibited. A chamber separated by a weir is provided above the upper drum, a hot water outlet is provided in this chamber, and a pressure detector is provided above the upper drum to detect the vapor pressure within the drum. With a simple configuration in which the controller determines the hot water temperature based on the pressure-temperature characteristics from the signal and controls the hot water temperature by adjusting the fuel supply amount, hot water at the desired temperature can be easily and appropriately delivered in large quantities. It is also possible to increase the heat load of the boiler to achieve high performance.
Furthermore, the present invention provides a hot water boiler that enables easy and reliable temperature control of hot water by determining the hot water temperature from the steam pressure in the brackish water drum.

Hereinafter, the present invention will be explained in detail using embodiments shown in the drawings.

Figures 3 and 4 show an embodiment of the hot water boiler according to the present invention, and in these figures, parts that are the same as or correspond to those in Figures 1 and 2 are given the same numbers. Therefore, the explanation will be omitted.

Now, according to the present invention, of the upper and lower drums provided as a natural circulation type, the upper drum is configured as a brackish water drum 20 like a general steam boiler, and a water surface 28 is provided in this brackish water drum 20. water supply control to maintain the reference water level.
Furthermore, a cold water inlet 22 is provided opposite to the hot water layer 21 formed below the drum and connected to the water supply pipe 1, and a partition wall 23 is provided on the side inside the drum 20, and a water surface 28 of the hot water layer 21 is provided. A weir 24 is formed to store only nearby hot water, and this weir 2
Hot water is supplied from a hot water outlet 25 opened opposite to the hot water outlet 4. Here, the partition wall 23 has a substantially L-shaped cross section and is disposed along the longitudinal direction of the brackish water drum 20 which has a horizontally cylindrical shape, and the inlet 22 and outlet 25 are located inside the drum 20, respectively. below, to the sides of the weir 24, and correspondingly formed in the end wall of the drum 20. However, it goes without saying that the positions at which these openings 22 and 25 are formed are not limited to this. moreover,
26 in the figure is a pressure detector provided corresponding to the steam chamber 27 formed above the brackish water drum 20, and the pressure shown in FIG. 5 is determined by the steam pressure signal detected by this pressure detector 26. - The fuel supply amount is controlled by the controller 8 based on hot water temperature conditions obtained from temperature characteristics.

According to the above-described configuration, the load in the combustion chamber 3 can be increased as in a general steam boiler, and boiler water can be boiled in the combustion chamber water-cooled wall tube 4 and convection evaporation tube 5, Regardless of the load, the heat transfer coefficient within both tubes 4 and 5 can be maintained high, and the effect as a natural circulation type can be exhibited. Further, the steam generated in the pipes 4 and 5 described above becomes a steam/water mixture flow and is guided into the brackish water drum 20, heating the cold feed water flowing into this drum 20, and further heating the water surface of this hot water layer 21. Near 28, hot water is maintained at a saturated temperature by the steam above it. Then, as shown in FIG. 4, the hot water maintained at the saturation temperature passes over the upper edge of the partition wall 23, flows into the inner chamber of the weir 24, and is stored at the outlet 25 and the outlet pipe 6. It is sent to the outside via.

On the other hand, the temperature control of the hot water taken out to the outside through the weir 24 in the brackish water drum 20 described above is as follows:
As mentioned above, instead of the conventional direct temperature detection method which has a large time delay, we skillfully utilize the correlation characteristic between the pressure P and temperature T that is uniquely determined as shown in Fig. 5. The controller 8 adjusts the amount of fuel supplied to the combustion chamber 3 according to the hot water temperature condition determined based on the above characteristics based on the vapor pressure signal detected by the pressure detector 26. It is configured as follows. In particular, this type of pressure detection can be performed within 1/100 seconds at the latest because steam and pressure are transmitted at the speed of sound in the water in the pipe, and confirmation of hot water temperature using this steam pressure signal also requires signal processing. It is easy to perform and enables hot water temperature control without time delay.

Therefore, according to such a configuration, the heat load of the combustion chamber is allowed to be the same as that of a normal steam boiler,
Moreover, it can provide a hot water boiler that is economical and has excellent operational efficiency, especially when supplying hot water that requires large-scale demand such as in oil fields. Since temperature can be determined by simple comparison from pressure-temperature characteristics through pressure detection, the delay in temperature detection of hot water is greatly improved.
This has the advantage that temperature controllability can be significantly improved.

It goes without saying that the present invention is not limited to the structure of the embodiment described above, and that the shape, structure, etc. of each part can be modified and changed as necessary. For example, the lower drum 13 may not be necessary depending on the type of convection evaporation tube 5.

As explained above, according to the hot water boiler according to the present invention, of the pair of upper and lower drums, the upper drum is used as a brackish water drum, and is configured to exhibit the effect of a general natural circulation boiler, In the inner chamber of the weir formed by the partition wall installed above the drum, only hot water whose temperature is raised to near the saturated temperature by contacting the saturated steam above near the water surface of the hot water layer inside the drum is stored. Furthermore, a pressure detector is installed above the upper drum to detect the saturated pressure. Based on the vapor pressure signal, the controller determines the temperature of the hot water from the pressure-temperature characteristics. Based on this difference, the temperature of the hot water is determined. The temperature of hot water is controlled by adjusting the amount of water supplied.
Despite its simple configuration, it is possible to easily and reliably obtain a large amount of hot water at the desired temperature. By detecting the pressure and determining the hot water temperature, there are various excellent effects such as being able to easily and appropriately control the temperature of hot water without time delay.

[Brief explanation of the drawing]

1 and 2 are schematic configuration diagrams illustrating a conventional hot water boiler, respectively, FIG. 3 is a schematic configuration diagram illustrating an embodiment of a hot water boiler according to the present invention, and FIG. 4 is an enlarged view of the main parts thereof, FIG. 5 is a characteristic diagram showing the relationship between pressure and temperature. 1... Cold water supply pipe, 2... Water supply pump, 3...
Combustion chamber, 4... Combustion chamber water-cooled wall tube, 5... Convection evaporation pipe, 6... Hot water extraction pipe, 8... Controller, 9
... Burner, 10 ... Fuel supply pipe, 11 ... Fuel control valve, 13 ... Water drum, 20 ... Brackish water drum, 21 ... Hot water layer, 22 ... Cold feed water inlet, 2
3... Partition wall, 24... Weir, 25... Hot water outlet, 26... Pressure detector, 27... Steam room, 28
...Water surface.

Claims (1)

[Claims] 1. In a drum-type natural circulation hot water boiler that supplies hot water stored in an upper drum to the outside, the upper drum functions as a brackish water drum that stores saturated steam above it, and in this brackish water drum, an upper part of the A weir is provided in the section to take out only the hot water near the water surface that comes into contact with the saturated steam and is heated to near the saturated temperature, and a hot water outlet is connected to the chamber partitioned by this weir. 1. A hot water boiler characterized in that the temperature of the hot water is controlled by detecting the saturated steam pressure of the hot water, determining the hot water temperature based on pressure-temperature characteristics, and adjusting the amount of fuel supplied to the combustion chamber.