Support Shelves for Gasifier Dome and Thermocouple

Abstract

A gasifier lining comprises a first support shelf located directly under a dome area of the gasifier lining; and a second support shelf located directly under a thermocouple that penetrates the gasifier lining. A method of producing a gasifier comprising support shelves comprises providing a first support shelf directly under a thermocouple insertion area in a lining of the gasifier; and providing a second support shelf in the lining of the gasifier directly under a dome area of the gasifier.

Description

BACKGROUND OF THE INVENTION

The subject matter disclosed herein relates to gasifier vessel design.

A gasifier is a type of reactor used for partial oxidation of a fossil fuel, such as coal or a heavy fuel oil, to produce energy. A gasifier vessel comprises a wall, which may be an outer shell lined on the inside with an insulating lining. The insulating lining may comprise a plurality of layers. Conditions in the vessel may reach well over 700° C. during operation, which may cause thermal expansion in the plurality of lining layers. The various layers of the gasifier lining may expand at different rates. The effects of differential expansion are felt most in the dome area at the top of the gasifier, which experiences the total vertical expansion of the entire gasifier wall located below the dome. The expansion differential between the outer shell and the inner layers of the gasifier lining in the dome area may be about 3 inches in some embodiments, causing pressure between the inner layers and the outer shell, and possible damage to the gasifier lining.

The gasification process is monitored and regulated by thermocouples that penetrate the shell and the lining. The tip of the thermocouple is located at or near the hot inner surface of the gasifier lining, so as to measure the temperature of the gasification process and determine if conditions in the vessel are appropriate. Thermal expansion of the lining may cause stress in the area of insertion of the thermocouple. The thermocouple may be caught in between two lining layers of the gasifier that are expanding at different rates, resulting in possible breakage of the thermocouple.

Incorporation of a shelf into the gasifier wall is known to absorb movement from thermal expansion of the section of lining located below the shelf, protecting and supporting the section of the lining located above the shelf. However, there is a need in the art for support for the dome and thermocouple insertion areas of a gasifier lining.

BRIEF DESCRIPTION OF THE INVENTION

According to one aspect of the invention, a gasifier lining comprises a first support shelf located directly under a dome area of the gasifier lining; and a second support shelf located directly under a thermocouple that penetrates the gasifier lining.

According to another aspect of the invention, a method of producing a gasifier comprising support shelves comprises providing a first support shelf directly under a thermocouple insertion area in a lining of the gasifier; and providing a second support shelf in the lining of the gasifier directly under a dome area of the gasifier.

These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is an embodiment of a gasifier comprising support shelves for the dome and thermocouple.

FIG. 2 is an embodiment of a method for producing a gasifier comprising support shelves for the dome and thermocouple.

The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings.

DETAILED DESCRIPTION OF THE INVENTION

A support shelf absorbs movement from thermal expansion of the section of the gasifier lining below the shelf, protecting the section of the lining above the shelf. The thermocouple insertion area and the dome area of the gasifier lining are particularly sensitive to stress caused by thermal expansion; support shelves located below the thermocouple insertion area and the dome in the gasifier lining reduce stress in the dome and thermocouple areas. This results in increased lifespan and decreased maintenance for the dome area and thermocouple insertion area. The support shelves also divide the lining of the gasifier into segments, allowing the lining to be maintained and replaced in segments instead of as a whole, thus lowering maintenance time and costs for the lining.

FIG. 1 shows an embodiment of a gasifier 100 with a wall that comprises four layers: first refractory layer 101, second refractory layer 102, outer refractory layer 103 and outer shell 104. In the dome area 107, there may be a fiber layer (not shown) between the outer refractory layer 103 and the outer shell 104. The fiber layer cushions the expansion of layers 101, 102, and 103 of the dome 107 against pressure from the outer shell 104, as the outer shell 104 expands less than layers 101, 102, and 103. The outer shell 104 may comprise a metal vessel in some embodiments. Although three refractory lining layers are shown in the embodiment of a gasifier shown in FIG. 1, a gasifier may comprise any appropriate number of lining layers. Support shelves 105 and 106 extend partially through the refractory lining of gasifier 100. Support shelf 105 is located directly under the tangent line and base structure of dome 107, supporting and protecting dome 107, as vertical expansion of the portion of the gasifier lining below shelf 105 is absorbed by shelf 105. Gasifier 100 may comprise any appropriate number of shelves to support the dome 107; shelf 105 is shown for illustrative purposes. Support shelf 106 supports the area of insertion of thermocouple 108, absorbing the movement from thermal expansion of the portion of the gasifier lining located below support shelf 106. Support shelf 106 may be located directly beneath special refractory blocks that form the thermocouple assembly. While one thermocouple 108 and associated shelf 106 is shown in FIG. 1, a gasifier may comprise any appropriate number of thermocouples and associated support shelves.

The support shelves 105 and 106 may comprise metal in some embodiments. The metal shelves may be made of metal of a grade similar to the vessel shell, or from other high temperature alloys, such as alloy 800, in some embodiments. The support shelves may not extend to the hot face surface, or the shelves may become too hot. The shelves may be approximately 2 to 4 inches wide, embedded inside the third refractory layer. The shelves may comprise a horizontal plate, about 0.5 to about 1.0 inches thick.

Use of support shelves below dome 107 may reduce the upward expansion of the dome 107 to less than about one inch, and the thickness of the fiber layer between refractory layer 103 and outer shell 104 in dome 107 may be decreased accordingly. With less fiber for insulation, the dome temperature may be increased; the temperature limit of a typical fiber layer is 2600° F., although some fibers may be used up to 3400° F. Higher temperatures may lower the probability of dew point condensation and corrosion. The elevated temperatures made possible by minimization of fiber in the dome also allows for gasification of high dew point gases or feedstocks, which require higher temperatures for gasification.

Reduction of movement in the area of insertion of the thermocouple 108 greatly reduces pressure on the thermocouple 108, which may damage the thermocouple 108, and also reduces the probability of breakage of the thermocouple 108 caused by uneven thermal expansion of the refractory layers 101-103 and outer shell 104. Increased reliability of the thermocouple 108 allows for better detection of problems in the gasification process, improving the overall lifespan of the gasifier.

FIG. 2 shows a method of producing a gasifier comprising support shelves. In block 201, a support shelf is provided in the gasifier wall directly under a thermocouple insertion area. In block 202, a support shelf is provided directly under the dome area of the gasifier.

While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.

Claims

1. A gasifier lining, comprising:

a first support shelf located directly under a dome area of the gasifier lining; and

a second support shelf located directly under a thermocouple that penetrates the gasifier lining.

2. The gasifier lining of claim 1, further comprising a plurality of support shelves located directly under the dome area of the gasifier vessel.

3. The gasifier lining of claim 1, further comprising a plurality of thermocouples supported by a respective plurality of shelves.

4. The gasifier lining of claim 1, wherein the first and second support shelf are metal.

5. The gasifier lining of claim 1, wherein the lining comprises a plurality of layers.

6. A method of producing a gasifier comprising support shelves, the method comprising:

providing a first support shelf directly under a thermocouple insertion area in a lining of the gasifier; and

providing a second support shelf in the lining of the gasifier directly under a dome area of the gasifier.

7. The method of claim 6, further comprising providing a first plurality of thermocouples supported by a respective plurality of shelves.

8. The method of claim 6, further comprising providing a second plurality of support shelves located directly under the dome area of the gasifier vessel.

9. The method of claim 6, wherein the first and second support shelf are metal.

10. The method of claim 6, wherein the lining comprises a plurality of layers.