Abstract:
A vessel comprises a probe oriented downward from an outside surface of the vessel to an inside surface of the vessel. A method of operating a vessel, the vessel comprising a vessel wall having an inside surface and an outside surface, comprises: defining a hole extending through the vessel wall, the hole being oriented at a downward angle from the outside surface to the inside surface; and placing a probe in the hole; and preventing slag buildup around the probe during operation of the vessel.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The subject matter disclosed herein relates to a probe for a vessel. 
         [0002]    A gasifier is a type of vessel, or reactor, used for partial oxidation of a fossil fuel, such as coal or a heavy fuel oil, to produce energy. A vessel wall of a gasifier may comprise a shell lined on the inside with an insulating refractory lining. The refractory lining may comprise a plurality of layers. Conditions in the vessel may reach well over 700° C. during operation. The gasification process is monitored and regulated using probes or flanges that penetrate the shell and refractory lining. The tip of a probe may be located at or near the hot inner surface of the refractory lining, so as to determine if conditions in the vessel are appropriate. 
         [0003]    A probe may be inserted through the vessel wall and refractory lining through a hole, or opening, in the vessel wall and refractory lining that is oriented perpendicular to the vessel wall and the vessel center line. The hole is large enough to accommodate the probe, with additional space to prevent damage to the probe during expansion and contraction of the refractory lining at high temperatures. Different layers of the refractory lining may expand at different rates; the probe may be caught between two differently expanding layers, resulting in breakage of the probe. The extra space in the hole that allows for thermal expansion of the refractory lining may allow slag that is produced in the slagging vessel to flow inside the hole and come in contact with the probe. Slag penetration may cause damage to the refractory lining and corrosion of the probe&#39;s protective encasement or sheath. If the protective exterior of a probe is penetrated, any internal wires and materials may be damaged beyond use. Slag may also freeze in the hole, filling the space that allows for thermal expansion of the refractory lining, and causing the probe to break during expansion or contraction of the refractory lining. 
         [0004]    There exists a need in the art for a probe configuration for a slagging vessel that will prevent damage to the probe. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0005]    According to one aspect of the invention, a vessel comprises a probe oriented downward from an outside surface of the vessel to an inside surface of the vessel. 
         [0006]    According to another aspect of the invention, a method of operating a vessel, the vessel comprising a vessel wall having an inside surface and an outside surface, comprises defining a hole extending through the vessel wall, the hole being oriented at a downward angle from the outside surface to the inside surface; and placing a probe in the hole; and preventing slag buildup around the probe during operation of the vessel. 
         [0007]    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 
         [0008]    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: 
           [0009]      FIG. 1  is an embodiment of a vessel comprising an angled probe. 
           [0010]      FIG. 2  is an embodiment of a hole in a vessel wall for an angled probe. 
           [0011]      FIG. 3  is an embodiment of a method for producing a vessel comprising an angled probe. 
       
    
    
       [0012]    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 
       [0013]    A probe, examples of which may include but are not limited to a thermocouple, a chemical sensor, an optical sensor, or a pressure sensor, inserted in a hole that is oriented downward from the outside of a vessel wall to the inside of a vessel wall reduces slag flow into the hole by the force of gravity. The vessel lining grows upwards and outwards radially during thermal expansion; because the angled hole is oriented in the same direction as the lining growth, the angled hole moves with the lining as it expands and contracts. Therefore, the angled probe requires less additional space to allow for the expansion and contraction of the refractory lining. As the size of the hole in the lining is reduced, the amount of slag that penetrates the hole is also reduced. An angle of about 15 to about 45 degrees from the plane orthogonal to the vessel centerline may be implemented for the angled thermocouple probe in some embodiments. The reduction in the size of the hole is dependent on the penetration angle of the probe. A hole oriented perpendicular to the vessel wall may have a diameter of about 50 mm (2 inches). For an example hole at an angle of 45 degrees, the hole size may be reduced by as much as approximately 12 mm (0.5 inch), yielding an angled hole diameter of approximately 38 mm (1.5 inches), reducing slag fill volume by about 40%. 
         [0014]      FIG. 1  shows an embodiment of a vessel  100  with an angled probe. One probe is shown in the embodiment of  FIG. 1  for illustrative purposes; a slagging vessel may comprise any appropriate number of probes. The vessel wall  108  comprises three layers: outer shell  103 , outer refractory layer  102 , and inner refractory layer  101 . Although three layers are shown in the embodiment of  FIG. 1 , a vessel wall may comprise any appropriate number of layers. Probe  104  extends through a hole (shown below in  FIG. 2 ) that is oriented downward from outer shell  103  through the refractory layers  101  and  102  to hot inner surface  106 . Angle  107  between the plane  109  orthogonal to the vessel center line  105  and the probe  104  may be about 15 to about 45 degrees in some embodiments. Angle  107  reduces slag flow into the hole, as slag does not flow significantly against gravity. 
         [0015]    Angle  107  is oriented in the same direction as the movement of the slagging vessel refractory lining layers  101  and  102  during thermal expansion. Refractory lining layer  101  is at a higher temperature than refractory lining layer  102  during operation of the vessel; therefore, the upward and outward expansion of refractory lining layer  101  may be greater than the expansion of refractory lining layer  102 . The angle of angled probe  104  allows angled probe  104  to move with the expansion of the refractory lining layers  101  and  102 . Because the angled probe  104  is oriented in the same direction as the movement of the lining, the probe opening may move with the lining as the lining expands and contracts. This reduces the likelihood of breakage of the probe  104  caused by lining layers  101  and  102  expanding differently at high temperatures, extending the life of probe  104 . 
         [0016]    Referring to  FIG. 2 , which shows an embodiment of a hole in a refractory layer of a vessel wall for an angled probe, hole  201  the refractory layer  202  contains probe  203 , with extra space  204  to allow for expansion and contraction of refractory layer  202 . Additional space  204  may be reduced by about 40% by volume for angled probe  203 , as the angle probe moves in the same direction as the refractory layer  202  during thermal expansion. The reduction of additional space  204  reduces the amount of slag that may flow into hole  201 . 
         [0017]    Reduced slag infiltration into the refractory layers results in reduced damage to the refractory lining and extended life of a probe. Increasing the probe life contributes to increased reliability for the vessel by allowing for accurate monitoring of the conditions inside the vessel. Increased probe life also reduces planned and unplanned maintenance outages and vessel shutdowns, saving costs associated with loss of production and maintenance. 
         [0018]      FIG. 3  shows an embodiment of a method  300  for operating a vessel having an angled probe. In block  301 , a hole in the vessel wall is defined that is angled downward from the outer surface of the slagging vessel wall to the inner surface of the vessel wall is provided through the vessel wall. In block  302 , a probe is placed in the angled hole. The angle of the hole may be about 15 to about 45 degrees from the plane orthogonal to the vessel centerline in some embodiments. In block  303 , slag buildup is prevented on the probe during operation of the vessel. 
         [0019]    Although an angled probe has been discussed above in the context of a gasifier for illustrative purposes, an angled probe may be incorporated into any type of vessel, examples of which may include, but are not limited to, a slagging vessel, a coal-fired boiler, a solid waste incinerator, a shaft furnace, or a thermal oxidizer. 
         [0020]    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.