Recycle internal

Circulating fluidized-beds do not contain any in-bed tube bundle heating surface. The furnace enclosure and internal division wall-type surfaces provide the required heat removal. This is possible because of the large quantity of soflds that are recycled internally and externally around the furnace. The bed temperature remains uniform, because the mass flow rate of the recycled soflds is many times the mass flow rate of the combustion gas. Operating temperatures for circulating beds are in the range of 816 to 871°C. Superficial gas velocities in some commercially available beds are about 6 m/s at full loads. The size of the soflds in the bed is usually smaller than 590 p.m, with the mean particle size in the 150—200 p.m range (81). 

Large amounts of sodium sulfate are produced as a by-product of many diverse industries. Some of this material is recycled internally, some is upgraded and sold as a product. Most is disposed as a waste in landfills, or discharged to deep-wells, or bodies of water. [129,269]... 

Lindroos, L. (2002). Balance of arsenic and recycling. International Research Group on Wood Preservation, Doc. No. IRGAVP 02-50189. 

In most foundries, casting sands are recycled internally until they can no longer be used for casting. At that time, many of the sands, such as those from iron foundries, are landfilled as nonhazardous waste. Casting sands used in the production of brass castings may be contaminated with lead and must be disposed of as hazardous waste. Methods which can be employed to reduce the toxicity or volume of these wastes are discussed below ... 

The leakage-flow of non-contact gap and labyrinth seals can be considerable, and must be recycled internally. It should be noted that labyrinth compressors use this type of seal on the rods, also. 

Fandel G, Stammen M (2004) A general model for extended strategic supply chain management with emphasis on product life cycles including development and recycling. International Journal of Production Economics 89 293-308... 

K. J. Thome-Kozmiensky, Pyrolysis of wastes. Recycling International, EF-Press, Berlin 1985. 

T. L. Pohlen, M. Farris n, Reverse Logistics in Plastic Recycling, International Journal of Physical Distribution Logistics Management, 22(7), 35-47 (1992). 

In the above equations, M is the mass flow rate of the stream indicated by its subscript, oris the ratio of the total plant capacity (X,) that is sold as product while (l-o) is the ratio of X, that is regarded as waste stream. Zn is the proportion of the waste stream that is untreated while Zu is the proportion that is treated. Z21, Z22 and Z23 are the ratios in which the untreated waste is split to be recycled internally, to be sold to a neighboring plant and to be disposed off respectively. In a similar way, Z31, Z32 and Z33 are the ratios in which the treated waste is split to be recycled internally, to be sold to the market and to be disposed off respectively. The renewable and non-renewable feed streams are represented by Ri and M respectively. In equation 10.24, is the ratio of the amount of the nonrenewable feed (sum of A, and ) to the... 

A dip tube was added to the reactor vessel so that the F-T catalyst slurry could be recycled internally via a natural convection loop. The unreacted syngas, F-T products, and slurry exited into a side port near the top of the reactor vessel and entered a riser tube. The driving force for the recirculation flow was essentially the difference in density between the fluid column in the riser (slurry and gas) and that of the dip-tube (slurry only). The dip tube provided a downward flow path for the slurry without interfering with the upward flow of the turbulent syngas slurry mixture. Thus, to some degree, back mixing of the slurry phase and wall effects in the narrow reactor [3] tube were minimized. 

H. Thumm in Recycling International, 4th International Recycling Congress, EF-Verlag, Berlin 1984, pp. 1074-1077. 

Some processes are evaluated with the tacit assumption that compounds recycled internally stay within the process. Almost always a makeup stream of the recycling compound is introduced (although perhaps intermittently). A makeup stream should be a clear indication that the recychng compound is leaving the process. If the recychng compound has a high enough PEI, then analyses must take it into account in order to be complete. 

The concept of thermochemical H2 production from H2O was first given in the 1960s. In thermochemical H2O decomposition, H2O splits into H2 and O2 using a series of chemical reactions. AU chemical intermediates are recycled internally within the process so that H2O is the only raw material and H2 and O2 are the only products (Orhana, Dincer, Rosen, Kanoglu, 2012 Rosen, 2010). 

Figure 15.32 Schematic of dual-ion composite oxide-molten carbonate electrol3de showing how CO2 is ferried across the membrane anion, which is recycled internally.

Anon. (2001), Infinity and beyond. Carpet recycling, International Carpet Bulletin -(ICB) March, 8-10. 

He noted that the cost of large volume very low level waste disposal in Centre de I Aube is too expensive and that other solutions are being sought. Limited experience exists in France of metal recycle internal to nuclear industry - it has been handled on a "case by case basis" - there is no national scheme for handling such wastes. He discussed press reactions to radioactive sources found... 

For high-activity catalysts, the required heating time of a particle has to be relatively short. This is especially true for systems in which the products and selectivity are sensitive to temperatures. For high-velocity operations, solid particles are recycled internally or externally back into the reactors. The temperature of the particles in the reactor is usually different from that from recycle. It is imperative that particles of two different temperatures rapidly mix so that the tempera-... 

Materials Efficiency Use of internally recyclable materials Good. Majority of waste products recycled internally. 

During extended natural periods of drought there is little or no measurable water loss or CO2 assimilation. The plants apparently maintain a favorable carbon balance by continually recycling internal CO2 through the CAM pathway (Szarek et al., 1973). It is a unique property of the CAM plants that they are able to persist for extended periods without net CO2 exchange (see Fig. 6.7). 

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