INTEGRATED GASIFIER, RADIANT SYNGAS COOLER AND SUPERHEATER CONFIGURATION
Publication Date: 2014-Aug-27
The IP.com Prior Art Database
Improve the heat transfer efficiency in radiant syngas cooler (RSC) by using forced convection heat transfer (including radiation) and to utilize the heat available in the gasifier to superheat the saturated steam generated in RSC. The configuration provides forced convection heat transfer through the RSC by forcing the syngas through annular passages formed between two sets of water tubes. The saturated steam produced in RSC is sent through a bundle of tubes surrounding gasifier to produce superheated steam. This bundle of tubes around the gasifier superheater section utilizes a part of heat from the gasifier along with the enthalpy left in the syngas after the heat transfer in RSC to produce the superheated steam.
The idea is to make a compact radiant syngas cooler (RSC) and integrate the superheater by utilizing the heat from the gasifier. Compact RSC configuration is made by changing the heat transfer mode to forced convection (and radiation) instead of radiation/ natural convection. The configuration allows syngas to pass through narrow passages to make the forced convective heat transfer mode dominant. In the present concept, the number of defined flow passages is two. The first passage is similar to existing passages with platen tubes arranged in radial/ segmented configuration and is expected to have a similar heat transfer mode and flow pattern. Natural convection (and radiation) are the predominant mode of heat transfer in the first passage. A small liquid pool is maintained at the bottom to collect the solids. Unlike existing configurations where the syngas enters the quench through the RSC cone, in this concept syngas is forced to pass in upward direction through an annular passage formed by the platen tubes and the membrane tubes.
In the second passage, the gaps are adjusted and velocities are maintained to ensure that the forced convection (and radiation) mode of heat transfer is dominant. A sufficient gap is maintained to avoid the effects of solids clogging and obstructing the flow passage. A bell shape structure is provided at the passage bottom to ensure that the deposition of fly ash particles is as minimal as possible. The annular gap is extended to the top of the gasifier thereby allowing the syngas to flow through the annulus gap up to the top of the gasifier. There is also a set of water tubes provided circumferentially along the gasifier shell to superheat the steam. Steam generated from RSC could be fed into the superheater section to generate the superheated steam.
Superheated steam is generated by utilizing the heat available in the gasifier through the shell and the enthalpy that the syngas carries after exiting the RSC. As there is a provision to cool the gasifier, the gasifier could possibly be operated at much higher temperatures and less refractory. Syngas exits out of gasifier and RSC at the top, while the syngas can be directly taken to a scrubber.
Technical advantages of this process may include: Improved efficiency of RSC by...