SYNGAS COOLER ANNULAR SEAL
Publication Date: 2013-Jun-06
The IP.com Prior Art Database
Annular seals are used in syngas coolers in the annulus space between the tube cage and the vessel to prevent the leakage of corrosive syngas and to create an airtight space for nitrogen pressurization to prevent burst of the tube cage. New designs of seals are disclosed in this publication that use the concept of interference fit to create air- tight sealing surfaces, one with a circular bump at the sealing surface and the other with a labyrinth type of sealing surface. In another configuration a spring loaded pillow seal is envisaged. Other configurations disclosed include flexible fabric seals, hula seal and vertical bellows seals, which can be used depending on the design requirement. A flapper check design is also disclosed that allows for controlled leakage of nitrogen gas. The mating surfaces in the various seal configurations could be lined with removable wear-resistant insert rings or segments, as required, for easy maintenance and better performance. To provide for additional flexibility in terms of controlled leakage, hybrid bypass designs including both bellows and fabric or braided metal seals could be used.
This publication relates to syngas cooler annular seal.With today’s growing awareness of human caused climate changes there is a big interest to replace fossil fuels with renewable fuel sources, such as biomass fuels. The temperature level for many biomass gasification processes is in the region of 800-900°C . Since the gas contains different contaminants it has to be cleaned before the gas can be used as a fuel in a gas turbine.
The key issue is that all of these cleaning processes, even so called hot gas clean up, will require temperatures far below those of the gasification process, therefore demanding gas cooling. Gas cooling is also a way to make use of the sensible heat in the syngas, for example by producing steam. The most common types of gas cooler used in gasification systems are conventional convection cooler, either the fire-tube boiler design or the water-tube boiler design, with water/steam as cooling agent, as shown in Figure 1. Syngas cooler annular seal is a controlled leakage seal or baffle for the lower annular section of the syngas cooler, as shown in the figure. It will allow nitrogen to leak through at a target leak rate to maintain a pressure differential across the tube cage housing the hot syngas flow from the gasifier. It will also keep the region above it dry while the area below remains wet.
Figure 1 Typical syngas cooler showing annular seal
BRIEF DESCRIPTION OF DRAWINGS:
New configurations of annular seal for syngas cooler are disclosed with reference to the following drawings:
FIGURE 1 shows a typical syngas cooler with annular seal
FIGURE 2 shows spring-hinged pillow seal
FIGURE 3A shows finger seal configuration
FIGURE 3B shows labyrinth seal configuration
FIGURE 4 shows hula seal
FIGURE 5 shows vertical bellows seal
FIGURE 6 shows flexible fabric seal
FIGURE 7 shows the SGC flapper check seals
FIGURE 8 shows insert wear rings as shell or membrane attachment
FIGURE 9 shows bypass options for vertical bellows/flexible fabric seals
To prevent the leakage of corrosive syngas new sealing devices are disclosed in Figure 2 to Figure 9.Figure 2 illustrates a design configuration of a spring-hinged pillow seal. It consists of a hinge, seal plate and seal pad. The seal pad is affixed to the seal plate. The multiple seal plate segments are axi-symmetrically placed in the annular space. As shown in Figure 2, a spring affixed to a clamp on the downcomer is used to tension the seal plate. Spring tension is adjustable by nut on rod which penetrates the seal plate. The spring allows the nitrogen to exit annulus at start-up and maintain differential pressure during normal operations. The seal can be installed bi-directional. One side is pressure energized and the other side is control-pressure relieved. The segments are connected by a tongue and groove which helps better sealing of baffle when it is closed.
FIGURE 2 Spring-hinged pillow seal
Interference fit s...