KR101009212B1 - Method of producing steam in a gas tube steam boiler and gas tube steam boiler for implementing said method - Google Patents

Abstract

The present invention relates to a steam head on the water surface, bounded by a heat exchange chamber (2) filled with water forming a water surface (2A), and a cylindrical wall (1) and a top plate (4) having a generally vertical axis (10). A space 5, a steam outlet 6 in communication with the steam head space 5, a gas tube 3 extending through the heat exchange chamber 2 and the steam head space 5, and a gas tube 3. Means for supplying heated gas to the gas tube 3 to generate steam flow from the water surface 2A by heat exchange between water and water, and directing the steam flow from the water surface 2A to the steam outlet 6. And steam flow conduits 7 ′ and 7 ″ disposed in the steam head space 5, so that the steam flow flows in the transverse direction, preferably generally perpendicular to the gas tube 3. At least one of the three) extends transversely through the conduit, the structure of the conduit being at least half of the steam of the flow, Preferably the entirety is constrained to flow along the flow path, the flow path being between the first point of the wall 1 and the second point of the wall 1 which is horizontally opposite to the first point when projected onto the horizontal plane. It has a length at least equal to the shortest distance of and the distance relates to a gas tube steam boiler, which is the diameter (D) of the circular cylindrical wall when the wall 1 is of circular cylindrical shape.

Steam boiler, gas tube, steam flow, heat exchange chamber

Description

FIELD OF THE INVENTION A method for producing steam in a gas tube steam boiler, and a gas tube steam boiler using the method.

The present invention relates to a method of producing steam in a gas tube steam boiler and to a gas tube steam boiler using the method.

With this method and apparatus, it is important to optimize energy transfer from gas tubes to water and steam in order to reduce the overall size of the boiler for a given energy output. Typically, key design factors include input gas temperature, exhaust gas temperature, and desired maximum energy output. That is, feed water temperature, steam pressure, temperature, and mass flow. Preferably the steam should be dry, more preferably superheated.

A gas tube steam boiler with a baffle plate that provides an annular opening along the boiler wall, wherein the gas tube is confined to flow from the water surface to the annular opening and from there to the centrally located steam outlet. It is known that steam boilers are provided in US 1,546,665. In this structure, most of the generated steam will pass through the gas tube only a distance corresponding to approximately 1/2 of the diameter of the gas tube boiler, so that the heat exchange between the gas tube and the generated steam will be insufficient.

Although not entirely, especially in marine boilers, the size of the boilers is very important because of the limited effective space, and one object of the present invention is therefore to provide an apparatus and method of the type which reduce the space requirements of the boiler.

According to the invention this object is

A heat exchange chamber filled with water forming a water surface, a steam head space above the water surface, bounded by a cylindrical wall and top plate having a generally vertical axis, a steam outlet in communication with the steam head space, and the heat exchange Providing a gas tube steam boiler comprising a seal and at least one gas tube extending through the steam head space;

Supplying heated gas to said gas tube to generate steam flow from said water surface by heat exchange between said gas tube and said water in said heat exchange chamber,

Directing the steam flow through the steam head space from the water surface to the steam outlet, in which at least half of the steam in the flow of the head space, preferably generally entirely along the flow path Constrained to flow transversely, preferably in a direction that is generally orthogonal to the flow path, the flow path being a first point of the wall and a second point of the wall horizontally opposite to the first point when projected on a horizontal plane. Having a length at least equal to the shortest distance therebetween, the distance being the diameter of the circular cylindrical wall when the wall is circular cylindrical, whereby residual heat of the gas tube is transferred to the steam flow. Is achieved by.

The heat transfer from the gas tube to the steam in the steam head space is significantly improved here, so that the efficiency of the boiler is increased, while the generated steam is dried and possibly overheated to have higher quality.

In a presently preferred embodiment of the method according to the invention, the horizontal projection of the flow path is at least twice the distance. In this way the contact between the gas tube and the steam flow from the water surface to the steam outlet is increased to increase heat transfer in the steam head space.

In a presently preferred embodiment of the method according to the invention, the steam outlet is located away from the axis of the wall, preferably near the wall of the head space, along all gas tubes before the steam flow leaves through the steam outlet. Restrict to flow sideways.

In a presently preferred embodiment of the method according to the invention, the horizontal projection of the flow path is from or near the first point of the wall passing through the axis to a second point of or near the wall opposite to the first point. Extends, preferably backwards from the second point and backwards at least near the first point. In this way the steam flow is preferably passed through all gas tubes at least twice before leaving through the steam outlet.

In a presently preferred embodiment of the method according to the invention, the steam flow rate is lower when flowing from the second point to the first point than when flowing from near the first point to the second point, the water surface and the steam outlet Provide a relatively high velocity, preferably approximately 15 m / s to 30 m / s, more preferably 15 m / s to 25 m / s, at a portion of the distance between the water surface and the steam outlet Over the remainder of the path, the gas tube passes through the gas tube at a reduced rate, preferably approximately 10 m / s to 15 m / s, whereby the high velocity provides turbulence around the gas tube to ensure high heat transfer and in steam It is possible to ensure that droplets hit the tube and evaporate.

In a presently preferred embodiment of the method according to the invention, the hot gas for the gas tube is provided from the combustion chamber when burning fuel such as oil, carbon dust, natural gas, etc. High temperature exhaust gases from internal combustion motors or gas turbines, or gases supplied from gas engines or oil-based engines used in ship propulsion or power generation, heating processes, industrial equipment and power plants, and the like may also be used. When using hot gas from the combustion chamber, the combustion chamber may be provided in contact with the water in the heat exchange chamber to deliver additional heating from the combustion chamber directly to the water.

The second aspect of the present invention,

A heat exchange chamber filled with water to form a water surface,

A steam head space above the water surface, bounded by a cylindrical wall and a top plate having a generally vertical axis,

A steam outlet in communication with the steam head space,

At least one gas tube extending through the heat exchange chamber and the steam head space,

Means for supplying heated gas to the gas tube for generating steam flow from the water surface by heat exchange between the gas tube and the water in the heat exchange chamber,

A steam flow conduit disposed in the steam head space for directing the steam flow from the water surface to the steam outlet, such that the steam flow flows transversely, preferably generally perpendicular to the gas tube; At least one of the gas tubes extends transversely through the conduit, the conduit configured such that at least half, preferably generally all, of the steam of the flow flows along the flow path, the flow path being in a horizontal plane. Has a length at least equal to the shortest distance between a first point of the wall and a second point of the wall that is horizontally opposite to the first point, the distance being the distance of the circular cylindrical wall if the wall is circular cylindrical. A gas tube steam boiler comprising a steam flow conduit, of diameter.

Such a gas tube steam boiler is particularly suitable for carrying out the method.

According to a third aspect of the present invention,

A heat exchange chamber filled with water to form a water surface,

A steam head space above the water surface, bounded by a circular cylindrical wall and a top plate having a generally vertical axis,

A steam outlet in communication with the steam head space,

At least one gas tube extending through the heat exchange chamber and the steam head space,

Means for supplying heated gas to the gas tube for generating steam flow from the water surface by heat exchange between the gas tube and the water in the heat exchange chamber,

A steam flow conduit disposed in said steam head space for directing said steam flow from said water surface to said steam outlet,

The steam flow conduit comprises a generally horizontal first plate disposed at a vertical distance h1 below the top plate, the first plate providing a first steam flow gap between the first plate and the wall. It relates to a gas tube steam boiler, having a first gap forming edge spaced apart from the wall.

Preferred embodiments of gas tube steam boilers according to the second and third aspects of the invention are shown in the claims 11 to 21 and 23 to 31 below, the advantages of which will become apparent from the detailed description which follows.

The invention will now be described in more detail with reference to the embodiments shown by way of example in the drawings.

1 schematically shows a vertical cross-sectional view taken along the A-A cross section of a boiler according to a preferred embodiment of the present invention.

FIG. 1A schematically shows the boiler of FIG. 1 viewed from above and shows lines taken in cross section in FIGS. 1 and 2.

FIG. 2 schematically shows a vertical cross sectional view taken along B-B perpendicular to the cross section of FIG.

Figure 3 schematically shows a perspective view of a baffle plate structure.

4-7 show four other possible structures of the boiler steam head space according to the invention.

The gas tube steam boiler shown in FIG. 1 has a heat exchange chamber 2 filled with water forming a water surface 2a, a cylindrical wall 1 having a generally vertical axis 10, a top plate 4, and a diameter D It comprises a steam head space (5) above the water surface, bounded by). The steam outlet 6 is connected to the steam head space 5, and several gas tubes 3 extend through the heat exchange chamber 2 and the steam head space 5. In order to generate steam flow from the water surface by heat exchange between the gas tube 3 and the water of the heat exchange chamber 2, the heated gas flows through the gas tube 3.

1 to 3 and 5, the steam flow from the water surface flows along a conduit bounded by baffle plates 7 'and 7 " 3) in the transverse direction, all the steam in the flow flows horizontally between the two baffle plates 7 'and 7 "upside down between the upper baffle plate 7" and the upper plate 4 It is restricted to flow in the opposite horizontal direction and to exit through the steam outlet 6.

As shown in Figs. 2 and 3, each of the two baffle plates 7 'and 7 "covers an area smaller than the cross-sectional area of the steam head space 5, and the two baffle plates 7' and 7" are separated. The edges extend vertically from the top plate 4 to the lower baffle plate 7 ′ in a vertical direction and extend in a horizontal direction across all of the individual positions on the cylindrical wall of the steam head space 5. Connected to the field.

The gas tube 3 extends upwards from the bottom of the boiler or from the combustion chamber 14, as shown in FIG. 2, through the heat exchange chamber 2 and the steam head space 5 filled with water, with a steam head space ( In 5) the gas tube 3 extends through the holes of the plates 7 'and 7 "and the top plate 4 so that the gas escapes through the gas exhaust port 11.

The heat exchange between the gas tube and the water will produce steam entering the steam head space 5 at the water surface, and the plate 7 ′ has a gap forming edge 12 as the steam moves to the left as shown in FIG. 1) and move to right between the two plates 7 'and 7 "as shown in Figure 1, and turn the gap forming edge 13 to move between the plate 7" and the top plate 4 Go to (6). In this way, the steam is forced to move laterally relative to the gas tube 3 a distance corresponding to approximately twice the diameter of the boiler 1. Small steam leakage between the openings of the plates 7 'and 7 "and the gas tube 3 will not be a problem because the steam in this small gap will be in close proximity to the tube wall and heated in place. In order to provide sufficient heat exchange between the steam flows, at least half of all steam in the flow of the head space is restricted to flow transversely, preferably in a direction orthogonal to the gas tube along the flow path, the flow path being It has a length at least equal to the diameter of the circular cylindrical wall when projected onto the horizontal plane, which allows the present invention to provide the above-described US, in which less than half of steam flows a distance corresponding to less than 3/4 of the diameter of the circular cylindrical wall. 1,546,665.

When steam leaves the water, it typically contains small water droplets, and the water droplets impinge upon the gas tubes 3 and evaporate by a pressurized flow across the gas tubes 3 at a relatively high flow rate, The relatively high velocity of steam also provides heat exchange between the steam and gas tubes in the steam head space 5, which heat exchanges the gas tubes 3 in the open steam head space without plates 7 ′ and 7 ″. This is increased in comparison with conventional boiler structures, where the flow flows slowly parallel to the steam outlet from the water surface to the steam outlet, which is mainly parallel to the current, and also to avoid the high concentration of water droplets in the steam leaving the steam outlet 6. The distance between the water level and the top plate, which is generally relatively long, can be reduced.

When the water in the boiler 1 does not boil, the water level inside the boiler corresponds to the level measured by other traditional equipment, such as the pressure difference between the two well-known levels, water level glasses and the like. However, the actual water level seen inside the boiler will be high due to the presence of a large amount of steam bubbles inside the water zone, and the water level will vary somewhat depending on the heat load and steam pressure. The highest water level will be around the gas tube 3, so that the gas tube is wetted by the water up to this water level, which is typically at the designated surface, which will be described later in cold conditions, It is about 250 mm above the measured water level.

The overall height h of the steam head space 5 is equal to the distance h1 between the top plate 4 and the first plate 7 "and between the first plate 7" and the second plate 7 '. Is divided by the distance h2 and finally the distance h3 between the second plate 7 'and the water surface in cold conditions.

In a preferred embodiment the distances h1 and h2 are such that the steam velocity between the top plate 4 and the first plate 7 "is approximately 10 m / s to 15 m / s and the two plates 7 'and 7". Steam speeds in between are dimensioned to be approximately 20 m / s to 30 m / s. In other words, the distance h1 is approximately twice the distance h2. The distance h3 should be sufficient to ensure that in all situations the actual water level is approximately 200 mm below the second plate 7 'while boiling at full load.

In the steam head space, as described above, the flow of steam perpendicular to the gas tube 3 is relatively fast between the two plates 7 'and 7 "and slightly slow between the top plate 4 and the plate 7". There will also be any cross flow to the gas tube 3 between the water surface and the plate 7 ′. Compared with the traditional situation where the steam head space 5 moves steam at a low speed, generally parallel to the tube, the steam speed provides a higher heat transfer coefficient from the gas tube 3 to steam. In fact, the heat transfer is almost identical to the heat transfer present in the heat exchange chamber 2 filled with water, in which the water is in direct contact with the gas tube 3.

The steam produced is actually superheated as well as free of water droplets when leaving the boiler via steam outlet 6. This overheating will ensure that salt does not leave the boiler, and as a result will not cause deposits in the steam pipe from the boiler to the user. In addition, possible steam outlet valves behind the steam outlet can be dimensioned at higher steam rates. That is, the size of the valve can be reduced, thereby saving both the space and the weight and cost of the steam outlet valve. In addition, the entire heating surface can be reduced due to increased heat transfer. That is, the tube length, the number of tubes, and the height of the boiler are reduced, reducing both the weight and cost of the boiler.

In the table below the treatment data for the gas tube steam boiler according to the invention is shown.

Boiler steam capacity kg / h 3700 Working pressure of steam barg 6.5 Saturation point ℃ 167 Fuel flow (HFO) kg / h 250 Flue gas flow kg / h 3900 Smoke tube dimensions mm ø18 × 2 Number of smoke tubes pcs 300 Overall tube length [from furnace top to boiler top] mm 1440 Boiler shell (inner diameter) mm ø1276 h1 (distance between boiler top plate and upper baffle plate) mm 125 h2 (distance between two baffle plates) mm 75 h3 [distance between bottom baffle plate and measured water level] mm 450 Boiling up (wet heating surface above measured water level) mm 250 Wet tube length mm 1040 2. Pass maximum steam speed (between two baffle plates) m / s 16 3. Pass maximum steam speed (between upper baffle plate and boiler top plate) m / s 10 Steam space volume load (up to measured NWL) h ^-1 1100 Inlet gas temperature (deviating furnace) ℃ 1360 Gas velocity (at the tube inlet) m / s 107 Gas temperature in the smoke tube at the actual water level (on the wet heating surface) ℃ 550 Outlet gas temperature ℃ 400 Outlet steam temperature ℃ 220

The table below compares a traditionally sized gas tube steam boiler (designated 'standard') with a gas tube steam boiler (designated 'new') according to the present invention. Both boilers are designed to have the same steam capacity, thermal efficiency (ie, the same salt pipe gas outlet temperature), and the same pressure drop.

division unit Standard new Tube dimension mm 18 × 2 18 × 2 Number of tubes pcs 375 300 Wet tube length mm 1370 1040 Length to normal water level (measured value) mm 1120 790 Steam space up to the measured water level mm 840 650 Overall tube length mm 1960 1440 Overall tube length in the boiler m 735 432

As a direct result of using the present invention, it can be seen that approximately 40% (approximately 240 kg) of the tubes of the standard boiler design can be saved. The shorter tube length also shortens the boiler height by 520 mm, providing a difference in plate weight of approximately 200 kg when boiler diameter 1300 mm and plate thickness 12 mm.

While the invention has been described above in connection with preferred embodiments, many variations can be envisaged without departing from the following claims. Among such variations, the omission of the second plate 7 ′ results in a simpler structure, but still a flow path in which most of the steam in the flow of the head space 5 has a length corresponding to the diameter of the boiler 1. To provide steam flow through the steam head space 5 from the water surface to the steam outlet 6 in a limited way to flow laterally through the gas tube. This possibility is shown in FIG. 4, and the preferred embodiment described above is schematically shown in FIG. 5. Other possibilities include steam flow from the water surface to the steam outlet, limited by a first plate with a central hole through which steam passes and a second plate on the first plate, as shown in FIGS. 6 and 7. Provided, wherein the second plate provides an annular opening along the boiler wall, restricting steam flow across the gas tube first radially outward and then radially inward towards the centrally located steam outlet 6. do.

In the embodiment of FIG. 7, the steam flow is confined to a spiral flow path by a spiral plate located between the central tube and the outer wall of the boiler 1, which steam flow is again opposite at least the wall of the boiler 1. It has a length corresponding to the distance between the two points.

Claims (31)

Steam head space 5 above the water surface 2a, bounded by a heat exchange chamber 2 filled with water forming the water surface 2a, and a cylindrical wall 1 and a top plate 4 having a generally vertical axis. A steam outlet 6 in communication with the steam head space 5, at least one gas tube 3 extending through the heat exchange chamber 2 and the steam head space 5, and the top plate 4. A first plate 7 "disposed downwardly at a vertical distance h1, said first plate 7" being a first steam flow gap between said first plate 7 "and said wall 1; Providing a gas tube steam boiler comprising a steam flow conduit having a first gap forming edge 13 spaced from said wall 1 to provide a gas flow conduit, said steam flow conduit comprising: Disposed in the steam head space 5 to direct the steam flow from 2a) to the steam outlet 6, the steam flow being At least one of the gas tubes 3 extends in a transverse direction through the conduit so as to flow transversely to the gas tube 3, the conduit in which at least half of the steam of the flow is along the flow path. The flow path is configured to flow, the flow path being a first point of the wall 1 when projected onto a horizontal plane, and a second point of the wall 1 that is horizontally opposite to the first point with respect to the generally perpendicular axis. Has a length at least equal to the shortest distance therebetween, the distance being the diameter of the circular cylindrical wall 1 when the wall 1 is circular cylindrical, and the first plate 7 "is the steam head space 5 Each of the edges of the first plate 7 "extending from the first gap forming edge 13 is connected to each other by vertical plates 9 to form a tube, Vertical plate 9 is a cylinder of the steam head space 5 Providing a gas tube steam boiler, which extends horizontally across all of the individual locations on the wall 1, Supplying heated gas to the gas tube to generate steam flow from the water surface by heat exchange between the gas tube and water in the heat exchange chamber; Directing the steam flow from the water surface through the steam flow conduit of the steam head space to the steam outlet, wherein at least half of the steam in the flow of the head space is transverse to the gas tube along the flow path Restricted to flow, the flow path having a length at least equal to the shortest distance between a first point of the wall and a second point of the wall horizontally opposite the first point when projected on a horizontal plane, the distance being If the wall is a circular cylindrical, the diameter of the circular cylindrical wall; The residual heat of the gas tube is thus transferred to the steam flow. How to generate steam. The method of claim 1, Residual heat of the gas tube is transmitted to the steam flow through the steam outlet to the extent that all the steam leaving the steam space is overheated How to generate steam. The method according to claim 1 or 2, The length of the flow path is at least twice the distance How to generate steam. The method according to claim 1 or 2, The steam outlet is located away from the axis of the wall How to generate steam. The method according to claim 1 or 2, The flow path extends from or near the first point of the wall passing through the axis to a second point or vicinity of the wall opposite the first point. How to generate steam. The method of claim 5, The flow path extends backwards from the second point and extends at least back near the first point. How to generate steam. The method of claim 6, The flow velocity of the flow is lower when flowing from the second point to the first point than when flowing from the vicinity of the first point to the second point. How to generate steam. The method of claim 7, wherein The flow velocity of the flow is approximately 10 m / s to 15 m / s when flowing from the second point to the first point, and approximately 15 m / s when flowing from near the first point to the second point. s to 30 m / s How to generate steam. The method according to claim 1 or 2, The heated gas may include a) a combustion chamber, b) a gas turbine, c) an internal combustion motor, d) a gas engine or an oil-based engine for use in ship propulsion or power generation, heating processes, industrial equipment and power equipment, Supplied from any source How to generate steam. The method according to claim 1 or 2, The steam flow flows in a direction orthogonal to the gas tube (3) How to generate steam. The method according to claim 1 or 2, The entire steam of the flow is restricted to flow along the flow path How to generate steam. A heat exchange chamber 2 filled with water forming the water surface 2a, A steam head space 5 above the water surface 2a, bounded by a circular cylindrical wall 1 and a top plate 4 having a generally vertical axis, A steam outlet 6 in communication with the steam head space 5, One or more gas tubes (3) extending through the heat exchange chamber (2) and the steam head space (5); Means for supplying a heated gas to the gas tube (3) for generating steam flow from the water surface (2a) by heat exchange between the gas tube (3) and the water in the heat exchange chamber (2); A steam flow conduit disposed in the steam head space 5 for directing the steam flow from the water surface 2a to the steam outlet 6, The steam flow conduit comprises a generally horizontal first plate 7 "disposed at a vertical distance h1 below the top plate 4, wherein the first plate 7" is the first plate 7 ". And a first gap forming edge 13 spaced apart from the wall 1 to provide a first steam flow gap between the wall and the wall 1, The first plate 7 "has an area smaller than the cross-sectional area of the steam head space 5, and each of the edges of the first plate 7" extending from the first gap forming edge 13 is vertical. The plates 9 are connected to each other with the top plate 4 to form a tube, the vertical plate 9 crossing all between the individual positions on the cylindrical wall 1 of the steam head space 5. Extending in the horizontal direction Gas tube steam boiler. The method of claim 12, The steam flow conduit comprises a generally horizontal second plate 7 ′ disposed at a vertical distance h2 below the first plate 7 ″, wherein the second plate 7 ′ is the second plate. A second gap forming edge 12 spaced apart from the wall 1 to provide a second steam flow gap between 7 'and the wall 1; Gas tube steam boiler. The method of claim 13, The first gap and the second gap are positioned opposite each other with respect to the axis. Gas tube steam boiler. The method according to any one of claims 12 to 14, The steam outlet 6 is located at or near the wall opposite the first gap with respect to the axis. Gas tube steam boiler. The method according to claim 13 or 14, The distance h1 is such that the flow rate of the steam flow is lower in the conduit portion located between the top plate and the first plate than in the conduit portion located between the first plate and the second plate. greater than h2) Gas tube steam boiler. The method according to claim 13 or 14, All of the gas tubes 3 extend through the first plate 7 "and the second plate 7 '. Gas tube steam boiler. The method according to claim 13 or 14, The water surface under cold conditions of the water is located at a vertical distance h below the top plate 4, the distance h1 is approximately 15% to 25% of the distance h, and the distance h2 ) Is approximately 7% to 13% of the distance h Gas tube steam boiler. The method according to claim 13 or 14, The first plate 7 "and the second plate 7 'have an area smaller than the cross-sectional area of the steam head space 5, and the first gap forming edge 13 and the second gap forming edge 12 Each of the edges of the first and second plates extending from each other are connected to each other by vertical plates 9 to form a tube. Gas tube steam boiler. delete delete delete delete delete delete delete delete delete delete delete delete

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