Efficient waste heat recovery in a cryogenic distillation air separation plant using heat pumps
The separation of the air in its components by cryogenic distillation has a high electric consumption due to the required air compression process. This work analyses the energy recovery of the heat dissipated at the intercooling stages of the main compressor by the integration of two types of heat pumps: an Absorption Heat Transformer (AHT) and a Vapour Compression Heat Pump (VCHP). The upgraded heat from the compressor is used in the regeneration of a Molecular Sieve used to eliminate some undesirable components before the distillation process. Real operation data from an air separation plant in Tarragona (Spain) is used to compare the two configurations using both types of heat pumps. The results show that the present consumption of thermal energy for the regeneration of the Molecular Sieve could be reduced up to 50%, when an AHT is coupled in series with the existing heating system and using first the waste heat at the desorber of the AHT and later at the evaporator of the AHT system with a Tcon=20°C. For the second configuration, the basic VCHP with a Teva=55°C and Tcon=120°C could reduce the thermal energy consumption almost up to 72% with a reduction of about 14% in the heat rejected to the ambient with respect to the current situation but with an additional expense in mechanical work for the heat pump of about 4%.
Single-Stage Vacuum Pressure Swing Adsorption for Producing High-Purity Oxygen from Air
The maximum oxygen concentration obtained using a conventional single-stage pressure swing adsorption unit is ca. 95% balanced mostly with argon. However, there are several applications requiring simple and compact units for producing high-purity oxygen (≥99%), such as medical, military, or aerospace. This article studies a single-stage vacuum pressure swing adsorption (VPSA) unit, loaded with silver-based zeolite AgLiLSX, for producing ca. 1 LSTP·min–1 of high-purity oxygen. The unit was designed on the basis of the experimental and simulation results obtained with a lab-scale unit. For a product concentration of 99.0%, the recovery obtained was ca. 8.0% with a productivity of 9.0 m3·h–1·ton–1.
List of the described Coleoptera ofTasmania.
The Coleoptera of Tasmania have never been considered as 
a whole since the time of Erichson, and no list or 
catalogue of the species has ever been compiled. About 
10,000 species have now been recorded from Australia and 
Tasmania, of which scarcely 400 have been described from 
Tasmania. A very imperfect knowledge of what species 
are confined to the island exists, as species supposed only 
to occur there, are constantly being found in Victoria and 
New South Wales, and even sometimes in Western Australia 
and Queensland; on the other hand, Tasmanian 
collectors frequently obtain mainland species which have 
never been recorded from Tasmania. 
I have considered it advisable, therefore, to prepare a 
list of the species hitherto recorded from Tasmania, adding 
to the list such species as I have seen in Tasmanian collections, 
or have myself taken in Tasmania. In this list, 
the genera and families are placed as far as possible in the 
order in which they appear in Masters' "Catalogue of the 
Described Coleoptera of Australia;" the species are placed 
alphabetically. All known synonyms have been omitted.