High Efficiency Absorption

Air streams from the digestion system, vacuum cooler, concentrator, and other areas where fluorine is evolved are connected to a highly efficient absorption system, providing extremely high volumes of water relative to the stream. The effluent from this absorption system forms part of the recycled water and is eventually discharged as part of the product used for fertilizer manufacture. The Minnesota plant requires a constant recirculating water load in excess of 3000 gpm (11.4 m /min), but multiple use and recycle reduce makeup requirements to less than 400 gpm (1.5 m /min) or a mere 13% of total water use. 

Monsanto Enviro-Chem offers NOx abatement technology that is licensed from Rhodia of France. It includes a High Efficiency Absorption (HEA) section for extended absorption and a catalytic reduction section (SCR) for Catalytic Destruction ofNOx (i.e., the DCN technology)99. 

Reproduced by permission of Monsanto Enviro-Chem Systems, Inc.) a DCN Destmction by Catalysis of NOx HEA High Efficiency Absorption... 

Two examples of the NOx treatment process unite that combine the high efficiency absorption columns and SCR reactor implemented by Uhde and Rhone-Poulenc are described in the next section. 

The principle of the high-efficiency absorption (HEA) column is liquid-phase oxidation and absorption. The product is a dilute nitric acid, which is recycled to tiie main absorption system. The nonabsorbed gases are heated and directed to the catalytic reactor (Rhone-... 

The process is a double-pressure 0.5/1.5 MPa process. A high-efficiency absorption tower ensures 99.9% efficiency. After treatment the gas contains 40 ppmv of NOy. The double catalyst system (1 step-. Pt-RH, 11 step ... 

The coolant for the HTGR is helium. The helium is not corrosive has good heat properties, having a specific heat that is much greater than that of CO2 does not condense and can operate at any temperature has a negligible neutron absorption cross section and can be used in a direct cycle, driving a gas turbine with high efficiency. 

Available in metal and plastic, used in large and small towers for distillation, absorption, scrubbing, liquid extraction. High efficiency, low HETP, low pressure drop. Limited data available. 

Yet another alternative is the thin-film solar cell. This cannot use silicon, because the transmission of solar radiation through silicon is high enough to require relatively thick silicon layers. One current favourite is the Cu(Ga, InjSci thin-film solar cell, with an efficiency up to 17% in small experimental cells. This material has a very high light absorption and the total thickness of the active layer (on a glass substrate) is only 2 pm. 

The inhibitor should not decompose during the life of the pickle nor decrease the rate of scale removal appreciably. Some highly efficient inhibitors, however, do reduce pickling speed a little. It would be expected that since the hydrogen evolution is reduced the amount of hydrogen absorption and embrittlement would also be reduced. This is not always the case thiocyanate inhibitors, for example, actually increase the absorption of hydrogen. 

We have also tried the trapping reactor system, in which ammonia is trapped on the catalyst/adsorbent and microwave is irradiated intermittently. However, due to the small specific surface area and the small ammonia adsorption capacity on the employed CuO, the trapping system was not effective compared to the continuous irradiation. Further study should be made to develop a material having high ammonia adsorption capacity and high efficiency for microwave absorption. Supported CuO on high surface area material or preparation of high surface area CuO can be effective. 

In these dye-functionalized dendrimers, light absorbed by the numerous peripheral coumarin-2 units is funneled to the coumarin-343 core with remarkably high efficiency (toluene solution 98% for the first three generations 93% for compound 8). Given the large transition moments and the good overlap between donor emission and acceptor absorption, energy transfer takes place by Forster mechanism [34]. 

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