Plate recuperators

Recent developments in manufacturing technologies (laser welding) have allowed the manufacture of cost-effective recuperators based on the spiral concept (Figure 10) or the folded-plate recuperator (14-15). 

Figure 26.4 Multi-plate air-to-air heat exchanger (Courtesy of Recuperator Ltd)...

Recuperator LP inlet Common manifold for all modules. Baffle plates above, below and between modules. Linear seals defining a multiple sided polygonal cylinder. One manifold per module. Single horizontal top plate above modules. Segmented cylindrical piston rings between module and top plate, and at I.D. at top plate. Eliminates linear seals and baffle plates between modules Uses same type seal as turbine exhaust... 

The efficiency of the GT-MHR (GT-MHR = Gas Turbine-Modular High Temperature Reactor) is 47 % at the gas turbine-inlet temperature of 850 C, lit. ETZEL-1994, table 1. The gas turbine cycle includes a compact plate fin recuperator. An important design feature in that project is that all part of the gas turbine and the heat exchangers, as well as the generator, are located in the power conversion vessel. 

The following are some important design criteria for water injection systems. Arrangement of the nozzles. The nozzles should be located on the roof or on the outlet end wall of the cooler. There should be several nozzles, whose jets should not overlap. Wetting the clinker must not begin earlier than at least five rows of plates past the recuperative zone and must be completed at least five rows ahead of the discharge end of the grate, so as to ensure that recuperation will not be impaired and that all the water will have evaporated before the clinker leaves the cooler. 

Two types of filters are used for lees filtration diatomaceous earth rotary vacuum filters and plate-and-frame filters (using 1-1.5 kg of perlite/hl of lees filtered). These two methods extract clear juice (less than 20 NTU), without clogging, at a rate of 1-2 hFh/m. Their recuperation rate is near 90% when the lees to be filtered contain 10% solids. There is practically no juice loss (Dubourdieu et al, 1980 Serrano et al., 1989). The juice obtained can be blended with clear juice from natural settling without a quality difference detectable by tasting or analysis. 

Components such as the compact plate-fm recuperator and the dry helium seals on the turbomachine have never been used under the helium conditions of the PBMR. 

Reference 9- 58 provides a summary of open literature for heat transfer and pressure drop correlations/test data for offset strip and wavy fin surface geometries. Only one set of test data for a fixed offset strip geometry have been identified for HeXe gas mixtures in the PrandtI/Reynolds regime being considered for the recuperator. Reference 9- 59 provides a summary of test data for various gas mixtures of HeXe for an interrupted plate fin geometry. 

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