JPS6237283B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high temperature air mixed steam generator for modifying the properties of wet saturated steam generated in a boiler.

The steam generated from a small standard boiler that is not equipped with a steam heater is wet saturated steam with poor dryness. Modern steam boilers have become smaller, and the amount of water held in the can is small, making carry-over more likely to occur during high loads when the most heat is needed. to
It is 0.9 to 0.7%, which means that it retains a large amount of condensate (moisture) and uses wet steam with a small amount of latent heat required for heat exchange, resulting in large heat loss.

The amount of heat retained by such wet saturated steam depends on its dryness (x). The dryness (x) here indicates the weight ratio of steam (gas) in wet steam. For example, since the heat exchange heat transfer surface of a heating material appliance such as a heater or a steam iron is formed by a limited supply steam holding volume and a heat transfer area, it is difficult to prevent moisture from entering such heating equipment. When a large amount of moist saturated steam is supplied, the steam loses its latent heat and begins to condense inside the heating equipment, and the dryness (x) inside the equipment is 0.6~
It stands at 0.7%. In other words, when the same amount of steam is supplied, the proportion of steam in the internal volume of the equipment becomes smaller, and the latent heat that only steam can hold becomes smaller, resulting in a significant decrease in heat absorption and utilization efficiency. do. In order to compensate for this, there is no choice but to supply a larger amount of wet steam, which has the drawback of increasing the amount of steam used by the boiler, which is directly linked to fuel loss.

As described above, in a heat transfer surface having a fixed volume, the volume ratio occupied by steam (void ratio) has a decisive influence on the heat consumption amount and heat absorption efficiency of the heating device.

On the other hand, the moisture generated from the wet saturated steam forms a thick drain layer on the heat exchange heat transfer surface of the heating equipment.

Since this drain layer has extremely poor thermal conductivity, it has the drawback of significantly reducing the heat absorption and utilization efficiency of the equipment.

This invention solves the above-mentioned drawbacks.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments shown in the accompanying drawings.

In FIG. 1, a steam boiler body a mainly consists of a heat insulating exterior body 1 and a water tube body 3 disposed in an internal firebox 2 thereof. The lower header 4 of the water pipe body 3 and the Hotwell tank 5 installed outside the machine are connected by a water supply pipe 7 via a boiler water supply pump 6.
The hot water in the Hotwell tank 5 is supplied to the water tube body 3 up to a predetermined water level and stored. Furthermore, the water pipe body 3 and header 4 are connected by a plurality of vertical water pipes 8, so that canned water can be circulated.

An oil burner 9 is placed facing one end of the lower part of the exterior body 1, and the combustion of the oil burner 9 heats the firebox 2 to approximately 1200°C. In the process of the high-temperature combustion gas moving in the direction of the arrow within the firebox 2, the canned water within the water tube body 3 is heated and evaporated, reaching a predetermined selected pressure within the steam chamber 10 above it. The upper part of the water pipe body 3 is connected to a main steam pipe 11, and the main steam pipe 11 further has a wet steam supply circuit 13 whose one end is opened in the suction mixer 12.
is connected to. In order to adjust the temperature, pressure, and transition of wet steam generated in the steam room 10, a boiler source pressure gauge 14, a main steam valve 15, a steam pressure adjustment valve 16, a wet steam mixing inlet check valve 17, and a wet steam thermometer are installed. 18, wet steam pressure gauge 19, etc. are installed in sequence. The pressure of the wet saturated steam sent to the suction mixer 12 through the wet steam supply circuit 13 is 5 kg/m ²
The steam temperature at that time is 158℃.

An outer box 20 of an air preheater b made of a heat insulating material is freely installed above the exhaust port 33 opened at the upper part of the exterior body 1. The lower part of the outer box 20 of the air preheater b is the exhaust gas supply port 2.
1, and an exhaust gas outlet 22 is opened at the top of the outer box 20. Air preheater outer box 20
A plurality of air heating tubes 24 held by upper and lower holders 23a and 23b are disposed inside. In order to increase the heat receiving area of the plurality of air heating tubes 24, it is desirable that each thin tube is arranged in a meandering shape. One end of the air heating tube 24 is connected to the air pressure feeding circuit 2
5, and an air pumping device 26 such as a compressor is attached to the end of the air pumping circuit 25. At predetermined positions of the air pressure feeding circuit 25, air pressure regulating valves 2 are sequentially installed in the air pressure feeding direction.
7, Air inlet thermometer 28, Air inlet pressure gauge 2
9. Air inlet check valves 30 are each installed to ensure smooth supply of air and to adjust the temperature and pressure of the air. The other end of the air heating tube 24 is connected to a heated air pressure feeding tube 31 , and the end of the heated air feeding tube 31 communicates with the suction mixer 12 . An exhaust pipe 32 is attached to the upper part of the exhaust gas outlet 22.

After heating the canned water in the firebox 2, the high-temperature combustion gas enters the air heating chamber 34 through the exhaust gas supply port 21 of the air play heater outer box 20 through the upper exhaust port 33 of the exterior body 1, and is sent to an air pumping device such as a compressor. The initial air at about 30°C pumped from the air heating chamber 34 heats the air in the air heating tube 24 to about 170 to 200°C with the waste heat of about 240°C in the air heating chamber 34.
Heated air at a temperature of 170 to 200° C. is sent to the suction mixer 12 at a constant pressure of 4.2 Kg/m ² through an air pumping circuit 25. The air pressure feeding circuit 25 includes a heated air outlet thermometer 35 of the preheater 20 in the order of circuit flow;
Outlet pressure gauge 36, auxiliary heated air release adjustment valve 3
7, heated air outlet check valve 38, heated air mixing inlet pressure gauge 39, heated air mixing inlet thermometer 4
0 and a heated air mixing inlet check valve 41 are respectively provided.

The above-mentioned auxiliary heating air release regulating valve 37 is used when steam is not used much.
This valve is provided to prevent the air temperature from decreasing due to a decrease in the flow velocity of the air inside the heated air pressure feed pipe 31, by opening the air release regulating valve 37 and releasing a small amount of heated air into the atmosphere. By improving the flow, the temperature of the pumped heating air can be maintained at 170 to 200°C at all times.

While supplying wet steam at 158°C at a constant pressure of 5Kg/ ^m2 through the steam pressure regulating valve 16, 4.2Kg/ ^m2
The high-temperature air at a pressure of 170 to 200° C. is sucked into the suction mixer 12 to mix the wet steam and the high-temperature air. This gas mixture is sent via steam supply piping 42 to an indirect heating device such as a heater or steam iron 43.

In the suction mixer 12, the pressure and temperature of two gases, namely wet saturated steam and high-temperature heating air, are the same and are mixed, so the kinetic energy (e=m ₀ ) of both gases is ² /2g) are equal. Also, each gas does not transfer external work or heat when it expands, so it conserves its kinetic energy, and even in a mixture of different gases, the kinetic energy is evenly distributed by colliding with each other. Even if the weight of the molecules differs, the above value of e=m ₀ ² /2g will be preserved for all types.
(Dalton's Law) In other words, in the case of the present invention, the temperature within the heating device is equal to the temperature at the time of mixing.

Also, the suction mixer 12 controls the wet saturated steam pressure (5Kg/m ² ) and the lower air pressure (4.2Kg/m 2 ).
m ² ) are suction-mixed, the air pressure feeding circuit 25
It has been experimentally confirmed that the air pressure on the suction mixer 12 side is the same as the pressure of wet saturated steam (5 kg/m ² ). Therefore, the heating device 4
During the heat exchange within 3, the steam component of the mixed steam is deprived of latent heat, and the amount of heat (sensible heat) held by the saturated water (drain water) remains.

High-temperature heated air has the property of adsorbing more condensed moisture in the form of bubbles due to its retained temperature and heat capacity, and the higher the temperature it has, the more moisture it retains in the form of bubbles. This effectively promotes heat absorption up to the heat absorption utilization range of the heating equipment. It is clear from the discharge state of the steam drain, for example, that heat exchange is efficiently achieved within the heating device when mixed steam is supplied. That is, when only wet saturated steam is supplied to the supply pipe 42 under the conditions of supply pressure Pw = 5Kg/m ² and supply steam rate of 1100Kg/H per hour, the steam drain pressure gauge 44 indicates a back pressure of 2.5Kg/m ² . Pressure is generated and the temperature of the steam drain discharged is 138°C as measured by the steam drain thermometer 45.
The temperature inside the tank rose to 98℃, and a self-evaporation phenomenon occurred. On the other hand, when the mixed steam of the present invention is supplied to the supply pipe 42 under the same conditions as above, the steam drain pressure is 0 kg/m, and the temperature of the steam drain is also 94°C as measured by the thermometer 45.
showed that. When this discharged steam drain was discharged untreated into the Hotwell tank 5 in the same manner as described above, the temperature inside the Hotwell tank was 85°C.

As described above, it has been found that when mixed steam is supplied, sufficient heat exchange is achieved within the heating equipment, and the absorption efficiency of the heating equipment can be maintained at a high level by the mixed steam itself. Also, the steam drain
Since it is recovered at a temperature below 100℃, heat loss during drain recovery can be minimized.

Also, if only heated air is sent to the supply piping,
Although the temperature of high-temperature air shows a rapid tendency to decrease before it reaches the heating equipment, the temperature of the high-temperature air can hardly be lowered by supplying it to the heating equipment in the form of a gas mixture of moist saturated steam and heating air. do not have. Note that 46 is a baffle plate.

Furthermore, FIGS. 2 to 4 show other embodiments of the air preheater b.

Figures 2 and 3 show a smoke tube type air preheater, in which a large number of smoke tubes 47 are arranged horizontally inside an outer box b, and in the process of transferring exhaust gas to the smoke tubes 47, the adjacent compressed air The compressed air inside the heating heater 48 is heated.

Further, FIG. 4 shows a plurality of compressed air heating coils 50 arranged in a helical manner around the outer periphery of a large number of vertical smoke pipes 49.
The figure shows air preheaters arranged in a shape.

As described above, this invention provides an insulating outer box having an exhaust gas supply port on one side and an exhaust gas discharge port on the other side, which is installed above the exhaust port of a steam boiler, and the inside of the insulating outer box. An air heating chamber is formed by disposing an air heating path with a large heat receiving area, one end of the air heating path is connected to an air pressure feeding device, the other end is connected to a heated air pressure feeding pipe, and the heated air pressure feeding pipe is The tip is attached to a mixer, and the mixer is configured to mix the steam used in the boiler with heated air at a higher temperature than this steam temperature, so that the wet saturated steam generated in the boiler is reformed. The mixed steam can be supplied to each heating device as a higher calorie dry mixed steam, and the mixed steam is supplemented with high temperature heated air in an amount proportional to the wetness of the wet saturated steam, and the gas is added to the generated steam. In other words, the same effect as increasing the dryness of the generated steam outside the boiler body regardless of the boiler function can be obtained, while at the same time the steam flow rate is greatly accelerated and the amount of condensate generated in the steam supply piping is also reduced. Furthermore, this mixture of steam is the gas (steam and hot air) at the heat transfer surface of the heating equipment.
By increasing the volume ratio (void ratio) occupied by
A larger amount of heat can be supplied to the heat transfer surface. At this time, the formation of the drain layer on the heat transfer facepiece can be minimized, which greatly improves the efficiency of heat absorption and effective utilization of the heating equipment, resulting in less heat consumption and a significant reduction in fuel costs. Moreover, from heating equipment that receives heat exchange by receiving mixed steam supply,
The steam drain can be discharged at a temperature of 100℃ or less, and since it can be installed above the boiler exhaust port, it can be used inexpensively in any steam boiler regardless of the model without modifying the existing steam boiler. Since the air heating device outside the boiler is installed, the heat-receiving area of the air heating path inside the outer box can be arbitrarily increased depending on the case.Furthermore, since the air heating path is at a lower temperature than the inside of the furnace, damage to the air heating path due to heat can be minimized, making it possible to As a result, the durability of the high temperature air mixed steam mixed steam generator itself can be improved. Furthermore, since waste heat is used, there is no need for any extra expense to obtain high-temperature air. In addition, before supplying mixed steam at the start of operation, only high-temperature air is forced into the supply piping to discharge residual condensate in the piping and heating equipment, reducing heat loss during steam startup supply. Also, it has excellent effects such as being able to completely eliminate the causes of water hammer and the like.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a sectional view of the used state, FIG. 2 is an enlarged sectional view of a smoke tube type air preheater, and FIG. FIG. 4 is an enlarged sectional view of the corrugated tube type air brake heater. a...Steam boiler body, b...Air preheater, 20...Outer box, 21...Exhaust gas supply port,
22...Exhaust gas discharge port, 24...Air heating pipe, 26...Air pressure feeding device, 31...Heating air pressure feeding pipe, 33...Exhaust port, 34...Heating chamber, 3
7...Discharge adjustment valve, 47...Horizontal smoke pipe, 49...
Vertical smoke pipe, 50...Heating coil.

Claims (1)

[Scope of Claims] 1. A heat insulating outer box 20 having an exhaust gas supply port 21 on one side and an exhaust gas discharge port 22 on the other side is installed above the exhaust port 33 of the steam boiler. The inside of the outer box 20 is an air heating chamber 34 in which an air heating path 24 with a large heat receiving area is arranged, one end of the air heating path 24 is connected to the air pressure feeding device 26, and the other end is connected to the heated air pressure feeding pipe 31. The heating air pressure feeding pipe 31 is connected to a mixer 12, and the tip of the heated air pressure feeding pipe 31 is attached to a mixer 12, in which the steam used in the boiler and the heated air having a temperature higher than the steam temperature are mixed. High temperature air mixed steam generator. 2. The high temperature air mixed steam generating device according to claim 1, wherein the air heating path 24 is a plurality of meandering thin tubes. 3 The air heating path 24 includes a plurality of spiral thin tubes 5
The high-temperature air mixed steam generator according to claim 1, wherein the temperature is 0. 4. The high-temperature air/mixed steam generator according to claim 1, wherein the air heating path 24 is a slit adjacent to a large number of horizontal smoke pipes 31 arranged in multiple layers in the horizontal direction. 5. The mixer 12 is configured to mix high-temperature heating air and humid steam while supplying humid steam generated from a steam boiler at a constant pressure, and to also suck pressurized air at a pressure lower than the steam pressure. The high temperature air mixed steam generator according to claim 1, which is a suction mixer. 6. The high-temperature air mixed steam generator according to claim 1, wherein the heated air pressure feed pipe 31 is provided with an auxiliary heated air release regulating valve 37 that can be opened and closed as appropriate.