Patent Application
20120131852
The invention relates generally to gasifiers, and more particularly to moisture removal at or near the exit of a quench chamber.
In a normal coal gasification process, wherein a particulated carbonaceous fuel such as coal or coke or a carbonaceous gas is burned, the process is carried out at relatively hot temperatures and high pressures in a combustion chamber. When injected fuel is burned or partially burned in the combustion chamber, an effluent is discharged through a port at a lower end of the combustion chamber to a quench chamber disposed downstream of the combustion chamber. The quench chamber contains a liquid coolant such as water. The effluent from the combustion chamber is contacted with the liquid coolant in the quench chamber; so as to reduce the temperature of the effluent.
When the fuel is a solid such as coal or coke, the gasifier arrangement permits a solid portion of the effluent, in the form of ash, to be retained in the liquid pool of the quench chamber, and subsequently to be discharged as slag slurry. A gaseous component of the effluent is discharged from the quench chamber for further processing. The gaseous component, however, in passing through the quench chamber, will carry with it a substantial amount of the liquid coolant. A minimal amount of liquid entrained in the exiting gas is not considered objectionable to the overall process. However, excessive liquid carried from the quench chamber and into downstream equipment, is found to pose operational problems.
In conventional systems, a baffle is placed in the gas exiting path in the quench chamber. Consequently, as liquid-carrying gas contacts the baffle surfaces, a certain amount of the liquid will coalesce on the baffle surfaces. However, the rapidly flowing gas will re-entrain liquid droplets by sweeping droplets from the baffle's lower edge.
There is a need for an improved quench chamber assembly configured to more effectively remove entrained liquid content substantially from the effluent gas.
In accordance with one exemplary embodiment of the present invention, a gasification assembly comprises a quench chamber having a liquid coolant disposed therein; a dip tube configured to couple a combustion chamber to the quench chamber and configured to direct syngas from the combustion chamber to the liquid coolant and produce a cooled syngas; and a transfer pipe in fluid communication with the cooled syngas, configured to transfer the cooled syngas to a downstream scrubber component, wherein the transfer pipe further comprises an excess moisture removal device, configured to remove moisture from the cooled syngas.
These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
In accordance with the exemplary embodiments disclosed herein, a gasifier having a quench chamber assembly configured to reduce temperature of syngas downstream of a gasification chamber is disclosed. The gasifier includes a quench chamber containing a liquid coolant disposed downstream of the gasification chamber. A syngas generated from the gasification chamber is directed via a dip tube to the quench chamber to contact the liquid coolant and produce a cooled syngas. A baffle is disposed proximate to an exit path of the quench chamber. In some embodiments, a draft tube may be disposed surrounding the dip tube such that an annular passage is formed between the draft tube and the dip tube. The cooled syngas is directed through the annular passage (if present) and impacted against the baffle so as to remove entrained liquid content from the cooled syngas before the cooled syngas is directed through the exit path. In some embodiments, a deflector plate is disposed between the liquid coolant and the exit path of the quench chamber and configured to remove entrained liquid content from the cooled syngas and prevent sloshing of liquid content to the exit path. In some embodiments, the baffle is asymmetric or symmetric, either open or angular, to remove entrained liquid content from the cooled syngas. In other embodiments, the baffle itself can have channels or cut-outs and overlays to remove entrained liquid and prevent sloshing of liquid content to the exit path. In other embodiments only dip tube is present and the annular section is formed between the dip tube and the quench chamber wall. The provision of asymmetric or symmetric shaped baffle, deflector plate, swirl generator, or combinations thereof substantially reduces entrainment of liquid content in the syngas directed through the exit path to the downstream components (e.g., scrubber assembly, etc.). An entrainment mitigation mechanism, or moisture removal device, is provided at, or along, the transfer pipe exiting the quench chamber. Specific embodiments are discussed in greater detail below with reference to
Aspects of the present invention relate to a gasification component, namely, a gasification quench chamber assembly, which includes the quench chamber, proper, and other appurtenances such as the quench chamber exit pipe, or transfer line. Quench is typically presented downstream of the gasification chamber and used to reduce the temperature of the manufactured syngas as well as remove (at least partially) solids/fines. In some embodiments, there may be a radiant syngas cooler located intermediate the gasification chamber and the quench chamber. As is typical, the syngas is introduced into the quench chamber via a dip tube. The quench chamber contains a liquid coolant, which reduces the temperature of the syngas. After quenching, the syngas rises up, due to buoyancy. Other features found in quench chambers include an entrainment baffle(s), or splash plate(s), present near the exit of the dip tub. The purpose of the entrainment baffle(s) is ostensibly to knock off water droplets, which are entrained with the outgoing syngas. As the entrainment baffle(s) is not 100% efficient in removal of the liquid from the syngas, liquid is still present in the syngas exiting the quench chamber via the exit pipe. The amount of fines and liquid entrainment in the outgoing syngas also poses a significant challenge in the instrumentation and/or measuring the amount of liquid getting entrained in the quench chamber exit pipe.
Aspects of the present invention increase the overall effectiveness and efficiency of the gasification system by improving upon the removal of entrained liquid from the generated syngas. Further aspects of the present invention address improved removal of entrained liquid while reducing manufacturing costs and/or operating expenses. Aspects of the present invention offer a simplified design, which additionally improve the life of the assembly and reliability, availability, and maintenance of the gasification plant.
The entrainment mitigation mechanisms depicted in
Referring to
The quench chamber 802 comprises a dip tube 806 which is configured to couple the gasification chamber 900 to the quench chamber 802 and is further configured to direct syngas 1000 from the combustion chamber 900 to a liquid coolant 804 contained in a portion of the quench chamber 802. The quench chamber 802 may further include an inlet line 805 for providing any requisite liquid coolant 804 to the quench chamber 804. By introducing the syngas 1000 to the liquid coolant 804, the syngas 1000 is cooled and exits the quench chamber as cooled syngas 1002 via the transfer pipe 870 towards the scrubber assembly 920. Upon the cooling of the syngas 1000 in the quench chamber 802, slag or fines 810, may precipitate out of the syngas 1000 thereby settling at the bottom of the quench chamber 804. The quench chamber 804 may further comprise at least one baffle 808 that aids in knocking out and/or off water droplets entrained in the exiting syngas 1002.
It should be noted that various configurations of quench chamber could be employed without departing from aspects of the present invention. For example, although
The transfer pipe 870 is configured to provide a means for transmitting the cooled syngas 1002 to the scrubber assembly 920 and other downstream components (not shown). The transfer pipe, or line, 870 further comprises an excess liquid removal device, or entrainment mitigation mechanism, 872 that is configured to further remove excess liquid (e.g., water, etc.) from the cooled syngas 1002 so that a cooled syngas 1006, with an even smaller amount of liquid, ultimately is conveyed to the downstream scrubber assembly 920 and other downstream components.
As shown in
In an embodiment a water injection line may also be provided, as denoted by 950 and 960. In this manner, water may be added along the line 870 in one or more locations. For example, as shown, the injection line may be located anterior to the 876 as denoted by 950. The injection line may be located within the moisture removal device 870. The water injection line may be located in either of these locations, or both locations, as well as any location along the transfer line 870.
Referring to
Clearly other configurations than those depicted in
Referring to
Referring to
Referring to
The centrifugal action or force and perforation embodiments are discussed above, in reference to
In accordance with one exemplary embodiment of the present invention, a gasification assembly comprises a quench chamber having a liquid coolant disposed therein; a dip tube configured to couple a combustion chamber to the quench chamber and configured to direct syngas from the combustion chamber to the liquid coolant and produce a cooled syngas; and a transfer pipe in fluid communication with the cooled syngas, configured to transfer the cooled syngas to a downstream scrubber component, wherein the transfer pipe further comprises an excess moisture removal device, configured to remove moisture from the cooled syngas.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.
