KR20080022967A - Steam generator to contain and cool synthesis gas - Google Patents

Abstract

A syngas cooler is provided to extend the service life of a unit and reduce fuel cost by recovering heat removed from a vaporizer enclosure region and transferring the recovered heat to a steam and water system of a vaporizing power plant. A syngas cooler(10) comprises: a body having an inlet(14) and an outer(36) formed thereon; a fluid-cooling internal flue formed in the body to contain syngas(12); a fluid-cooling external flue or enclosure region(28) formed in the body to receive syngas from the internal flue; a radiant heat transfer surface formed within the internal flue to cool syngas; and a transfer unit for transferring syngas from the external flue to the outlet. The syngas cooler further comprises a water tank(38) formed in a bottom part of the syngas cooler to contain and cool solids contained in syngas, and a solid discharge port(40) for removing solids from the syngas cooler. The fluid-cooling internal flue includes an internal enclosure wall(18) made of fluid-cooling tubes. The fluid-cooling external flue includes an external enclosure wall(30) made of fluid-cooling tubes. The radiant heat transfer surface includes fluid-cooling wing wall surfaces(20) which is integrally suspended to an inner part of the syngas cooler, and which are partially exposed to syngas flowing in.

Description

Syngas cooler {Steam generator to contain and cool synthesis gas}

1 is a side cross-sectional view schematically showing a first embodiment of a radiant syngas cooler according to the present invention.

FIG. 2 is a cross-sectional view of FIG. 1 as seen from line 2-2 of FIG. 1.

3 is a side cross-sectional view schematically showing a second embodiment of a radiant syngas cooler having a convection heating surface according to the present invention.

4 is a side cross-sectional view schematically showing a third embodiment of a radiant syngas cooler having an integrated vaporizer according to the present invention.

The present invention relates to the field of coal gasification, and more particularly to a syngas cooler to be used to contain and cool syngas to be produced in a coal gasification process.

Power plants for the Integrated Gasification Combined Cycle (IGCC), which burn solid fuels, should typically have a higher cost than competing solid fuel technologies, such as the pulverized coal combustion Rankine cycles. On the other hand, it has low reliability and work efficiency. The first component to make a more competitive IGCC includes an uncooled vaporizer and a radiant and convection syngas cooler. The radiative syngas cooler structure has a practical limit on the overall outer diameter due to the containment pressure and the limitations of the ship size at most plant sites. As a limitation to the diameter of such vessels, it is necessary to minimize the overall height of the radiant syngas cooler to maximize the radiant heat transfer steam generating surface to be used for cooling the gas.

US Patent Application No. 4,768,470, filed by Ziegler, uses a coaxial fuel structure with steam generating wall surfaces that shorten the overall height of the chiller. This structure has separate years with separate water circuits to provide separate disassembly and removal and inspection of internal and external flues. Another structure developed by The Hok Kok and Wilcox Company, Canada in 1992 is a single wall of steam generating wall with a secondary steam generating surface ("wing wall") suspended inside the year that lowers the chiller height and maximizes the surface area. Use year. Other companies, such as GHH Mann, use a similar structure.

Current solutions still do not reduce the cost of these components to competitive levels. The radiant single cooler for cooling syngas for power plants using large commercial gas turbines may exceed 150 ft. Some power plant structures use two coolers with reduced overall heights while increasing costs. In addition, pre-vaporizers, radiative coolers and convective coolers are provided in the plant design to substantially improve the plant's operational efficiency at substantial cost.

Current solutions for convection syngas coolers require a separate component from the radiant cooler with a cooling year connecting the two components. Convection chiller structures include water and steam tube structures (water or vapor in the tube, gas on the outside) (cell oil company) and flame tube structures (gas inside the tube, water on the outside) (Steinmueller, others ). These structures require pressure vessel enclosures and water / steam systems separately from radiative coolers. Gas flue and turbulence generated at the inlet in convection coolers create a source of fuel material that can cause operational difficulties.

The current solution for the vaporizer is to have a refractory enclosure to be uncooled and cooled. Uncooled enclosures (General Electric, Conoco, and others) will experience failures and frequent replacements. Typically, high efficiency as such a structure requires pre-carburet trains and gas turbines that burn oil or gas at high cost during the replacement time. Slow heating and cooling for the uncooled structure of the thick refractory extends downtime for repairing or replacing the refractory. Existing chiller vaporizer structures (Cell Oil Company, Future Energy, Inc.) use a separate water or steam generating circuit with a refractory coating to enclose and receive the vaporizer gas. Some of these systems are used with low pressure, forced circulation cooling water systems that dissipate heat out of the plant steam / water system, and with reduced efficiency. Conventional techniques for receiving molten slugs and hot solid fuel gases in combustion environments similar to those of these steam-using surfaces with integrated downstream cooling circuits are known as Cyclone ^TM Combustion Boilers (The Hancock and Wilcox Company). It is provided.

Therefore, the development of economical, compact, reliable and robust syngas coolers determines the future of commercial IGCC systems.

Accordingly, one aspect of the present invention relates to a syngas cooler that removes heat from syngas to be produced by a gasification process. Such a syngas cooler cools a fuselage having an inlet and an outlet, a fluid-cooled internal flue to be provided in the fuselage to receive the syngas, and a fluid-cooled external flue to be provided in the fuselage to accommodate the syngas at the internal flue Radiation heat transfer surfaces located within the internal flue and transport means for transporting syngas from the external flue to the outlet.

Another aspect of the present invention further relates to a syngas cooler as described above, which uses an assembly of convective heat surfaces located within the outer flue for cooling the syngas.

Another aspect of the invention relates to syngas coolers used in combination with integrated vaporizers as well as radiant and convective heat surfaces within the same fuselage.

New and various features of the invention are pointed out in the appended claims as part of the specification. In order to aid the understanding of the present invention, operational and operational advantages will be described with reference to the accompanying drawings and through the preferred embodiments of the invention illustrated.

Referring to the accompanying drawings, like reference numerals refer to like or functionally similar parts throughout the several views. In particular, FIG. 1 is a schematic side cross-sectional view of a first embodiment of the present invention, illustrating a radiant syngas cooler 10. Typically, the syngas cooler 10 is a cylindrical vessel having a longitudinal axis vertically. In this embodiment, the cooler 10 is supplied with hot syngas 12 from a vaporizer (not shown) to an inlet 14 provided on top of the cooler 10. Gas 12 is injected into the internal flue or enclosure region 16 provided in the cooler 10. The internal flue is preferably formed of a cylindrical inner enclosure wall 18 and consists of a typical fluid-cooling tube. The active fluid in the tube consists of water, steam or mixtures thereof. In addition to the fluid-cooling tube forming the inner enclosure wall 18, the inner flue 16 also includes a plurality of fluid-cooled wing wall surfaces 20 suspended inside the cooler 10, including a wing wall 20. The main part of the c) is exposed to the incoming syngas to heat the active fluid (water, steam, or mixtures thereof) to be transported through the wing wall 20. In general, the wing wall 20 is composed of flat tube banks provided adjacent to each other and includes an injection and discharge manifold or header portion 22 for dispensing or concentrating active fluid to be transported through the wing wall 20. Equipped. The number and arrangement of wing walls 20 to be provided is determined by heat transfer and other requirements. Therefore, FIG. 2 shows an arrangement of six wing walls 20 arranged around the vertical axis in the longitudinal direction of the cooler 10. The number of wing walls 20 is large and small is provided according to specific heat transfer and cooling conditions. . As the hot syngas 12 flows down through the internal flue 16, it cools down into the inner enclosure wall 18 and the wing wall 20, and the syngas 12 in the bottom region 24 of the internal flue 16. ) Moves through the one or more openings 26 provided in the inner enclosure wall 18 and actually moves upwards by changing the 180 ° advancing direction, and then the outer enclosure wall having a structure similar to the inner enclosure wall 18. It moves to the outer flue or enclosure region 28 formed by the 30. Thus, the outer flue 28 is actually annular. Manifold or header portion 32 is provided to facilitate the formation of opening 26 as needed. Syngas 12 is then conveyed upwards through external flue 28 and discharged out of cooler 10 by means of syngas outlet 36 through one or more openings 34.

The distance between the inner enclosure wall 18 and the outer enclosure wall 30 as well as the distance between the outer enclosure wall 30 and the fuselage 38 forming the cooler 10 can be approached and inspected when the cooler 10 fails. It will be big enough. Individually, the enclosure walls 18, 30 forming the inner and outer flues 16, 28 are preferably provided with independent fluid circuits to provide separate dismantling, removal and inspection. All water / steam generation surfaces will be arranged in a natural circulation scheme to eliminate the need for forced circulating systems with circulation pumps. Solids contained in the high temperature syngas 12 flowing downward through the inner flue 16 will be separated from the syngas 12 in the bottom region 24, and the syngas 12 will be the outer flue 28. Change the direction of travel upwards by about 180 °. The solid may be dropped into the water tank 38 provided at the bottom of the cooler 10 so that the solid may be cooled and removed through the solid discharge outlet 40. The soot blower 42 is provided in the opening portion 26 to be provided in the bottom region 24, so that if it is necessary to prevent the accumulated solids from being plugged, the syngas 12 moves 180 ° from the external flue 30. To be converted.

The combination of inner and outer flues 16, 28 with wing walls 20 located within the inner flue 16 actually lowers the overall height of the cooler 10 rather than the individual structure. With independent inner and outer flues 16,28 with spaces for dismantling and removal, the inner wall 16 accepts wing wall header portions 22 and connects within inner flue 16 (not shown). ), Especially at the bottom of the internal flue 16.

Depending on the amount of heat in the syngas 12 to be supplied to the cooler 10, an additional heat surface is required and a second embodiment of the invention is illustrated in FIG. 3 to achieve this. As is well known to those skilled in the art, the second embodiment shares a number of structural features in the first embodiment of FIG. 1, and in particular the convective heat surfaces arranged in the outer flue 28 as shown. 50). This convective heat surface 50 may be cooled with water or steam and arranged in one or more tube banks to allow syngas 12 to flow out of the tube. A bank of convective heat surface 50 is provided inside the outer flue 28 around the periphery of the cooler 10. In one aspect of this embodiment, the need for a separate cooling system, using the same fluidic circuit (integrated cooling) as the convective heat surface 50 is used on the steam generating surface consisting of internal and external enclosure walls 18 and 30 To exclude. Optionally, a separate fluid circuit is used for the convective heat surface 50. After flowing to the convective heating surface 50, the syngas 12 exits the external flue 28 via the opening 34 and exits the cooler through the gas outlet 36. Soot blower 52 may be provided for cleaning convective heat surface 50 to prevent plugging.

The convective heat surface 50 is not only a convective cooler component to be removed from the radiative cooler 10 but also a need for diverting connection years, the same pressure vessel, integral cooling in the case described above, and a separate cooling system. Exclude. The syngas 12 flowing upwards over the convective heat surface 50 located in the outer flue 28 in the radiative cooling section (inner flue 16) minimizes gas turbulence at the inlet to the outer flue 28. To actually move vertically. This minimizes the potential of uncontrollable ash plugs and allows for cleaning with a soot blower 52 adjacent the convective heat surface 50. This structure has particular advantages over turbulent flow and incidental uncontrollable plugging problems that will result from inconsistent injection into the tube into the injection tubesheet of the combustion tube cooler structure.

The simplified structure and equipment to be used for the gasification system can be achieved by means of the third embodiment of the present invention as shown in FIG. As shown, this assembly extends into a tube of enclosure walls 18 and forms an internal flue 16 upwards to form a fluid-cooling vaporizer enclosure region 60 in the upper region of the cooler 10. do. Therefore, the integrated vaporizer 60 is located in the cooler 10 to supply syngas 12 to the internal flue 16. The tube forming the enclosure wall 62 of the vaporizer enclosure region 60 protects the surface of the tube from molten slug and maintains the vaporizer enclosure region 60 at an appropriate temperature that may occur in the vaporization reaction. Has

The vaporizer enclosure region 60 according to the invention overcomes the problem by combining not only uncooled refractory vaporizers but also cooled vaporizers according to the prior art. The present invention improves on the conventional cooled vaporizer structure integrated in the same fluid-cooling circuit as the cooling circuit for the vaporizer enclosure region 60, eliminating the need for a separate cooling system. This structure recovers the heat removed in the vaporizer enclosure area 60 and transfers it to the vapor and water systems of the vaporization power plant, thereby extending the service life of the unit and providing fuel savings and improving efficiency.

While particular embodiments of the present invention illustrate and describe the application of the principles of the present invention in detail, they may be modified within the scope of the following claims without departing from these principles of ordinary skill in the art. In some embodiments of the invention, any feature of the invention is used with the advantage of not being used in correspondence with other features. Accordingly, all modifications and embodiments are intended to be within the scope of the following claims.

The description of the three embodiments described the technical advantages over the prior art. From a commercial perspective, the combined internal and external flue with wing wall structure reduces costs by reducing the overall height of the radiant syngas cooler. Such cost savings can be achieved not only with the reduced cost of the outer container, but also with the cost of transportation, fuel delivery, steel, and construction of components on site. Minimize maintenance costs by providing separable internal and external years. This is important for vaporization process coolers that are exposed to corrosive environments and require more time to maintain than flue gas coolers used in conventional pulverized coal plants.

The combination of convective heat surfaces integrated into the radiative cooling enclosure eliminates the cost of separate components. The cost savings are substantial because the reduced gas flue, steam and water pipe costs, steel construction costs, and construction costs can be saved to save a separate pressure vessel. Because of the plugging of convective coolers to be reduced or eliminated, the savings from high efficiency in solid fuel can extend the service life of the unit, making it larger than the overall total cost of the convective cooler.

Incorporation of an integrated chiller eliminates the need for a separate pressure vessel and cooling circuit, providing cost savings with a separate chiller. Compared to uncooled carburettors, it is more expensive and has high efficiency using solid fuel, which actually exceeds the difference in cost.

The cost savings of a combination of three structures that eliminate the pre-component train are important. These savings extend beyond the construction costs associated with the structure and the separate components, including the steel structures and all supporting equipment surrounding the components. Therefore, an important basic improvement to be provided with the present invention is to solidify the individual component members in one integrated component to be compact, low cost, reliable and maintainable.

Claims (18)

A fuselage having an inlet and an outlet; A fluid-cooled internal flue provided in said body to receive syngas; A fluid-cooled external flue provided in the fuselage to receive syngas from the internal flue; A radiant heat transfer surface located within said internal flue to cool syngas; A syngas cooler for extracting heat from the syngas produced by the gasification process consisting of a transport means for transporting the syngas to the outlet in the external flue. The syngas cooler of claim 1, further comprising a water tank provided in a lower portion of the syngas cooler for receiving and cooling solids included in the syngas, and a solid outlet for removing solids from the syngas cooler. The syngas cooler of claim 1, wherein the fluid-cooled internal flue comprises an enclosure wall made of a fluid-cooled tube. The syngas cooler of claim 1, wherein the fluid-cooled external flue comprises an enclosure wall made of a fluid-cooled tube. The syngas cooler according to claim 1, wherein the radiant heat transfer surface is composed of a fluid-cooling wing wall which is integrally suspended inside the syngas cooler, and is exposed to the syngas into which an important part of the wing wall surface is introduced. 6. The syngas cooler according to claim 5, wherein the wing wall surface comprises a plurality of tube banks to be adjacent to each other. The syngas cooler of claim 1, wherein the syngas is turned 180 ° in a bottom region of the syngas cooler such that syngas is transported from the internal flue to the external flue. 8. The syngas cooler of claim 7, wherein the syngas is carried through one or more openings in an enclosure wall forming the internal flue. The syngas cooler according to claim 8, comprising soot blowing means adjacent to one or more openings in the enclosure wall forming the internal flue. 5. The syngas cooler of claim 4, wherein the vehicle for transporting syngas from the external flue to the outlet has one or more openings in the enclosure wall forming the external flue. The syngas cooler of claim 1, wherein the external flue substantially surrounds the internal flue. 2. The syngas cooler of claim 1 having a convective heat surface located within said external flue cooling said syngas. 13. The syngas cooler of claim 12, wherein the convective heat surface arranges one or more tube banks to allow syngas to flow out of the tube. 13. The syngas cooler according to claim 12, comprising soot blowing means adjacent to the convective heat surface to wash the convective heat surface. The syngas cooler of claim 1, further comprising an integrated vaporizer for fluid-cooling in the fuselage to produce the syngas, wherein the integral vaporizer supplies syngas to the internal flue. 16. The syngas cooler of claim 15, wherein the unitary vaporizer is located in an upper region of the syngas cooler and consists of an enclosure wall of fluid-cooling tubes. 17. The fluid-cooling inner flue of claim 16, wherein the fluid-cooling inner flue consists of an enclosure wall of fluid-cooling tubes, and wherein the fluid-cooling tube that forms the inner flue is directed upward to form the enclosure wall of the unitary vaporizer. Syngas cooler. 17. The syngas cooler of claim 16, wherein the fluid-cooling tube of the enclosure wall forming the unitary vaporizer is coated with a refractory material.

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