Resin recovery system

Morrow makes a point of calling the system designed at CPRR a "resin recovery system, to stress the fact that it will work on about five different resins. Currently PET and HDPE can be processed together and are easily separated because of their different densities. The center hopes to add polystyrene and polyvinyl chloride to the mixed plastics stream they process. But, with the present technology, PET and PVC cannot be run together since they have similar densities. 

Uranium ores are leached with dilute sulfuric acid or an alkaline carbonate [3812-32-6] solution. Hexavalent uranium forms anionic complexes, such as uranyl sulfate [56959-61-6], U02(S0 3, which are more selectively adsorbed by strong base anion exchangers than are other anions in the leach Hquors. Sulfate complexes are eluted with an acidified NaCl or ammonium nitrate [6484-52-2], NH NO, solution. Carbonate complexes are eluted with a neutral brine solution. Uranium is precipitated from the eluent and shipped to other locations for enrichment. Columnar recovery systems were popular in South Africa and Canada. Continuous resin-in-pulp (RIP) systems gained popularity in the United States since they eliminated a difficult and cosdy ore particle/leach hquor separation step. 

The USEPA surveys identified four resin adsorption systems in the pesticide industry [7]. Phenol, pesticide, and diene compounds are all effectively removed by these systems. At least one system realized a significant product recovery via regeneration and distillation. The design surface loading rates vary from 1.0 to 4.0 gpm/ft with empty bed contact times of 7.5 to 30 minutes. 

The Lyondell plant (ARCO Chemical Company) operates one of the first industrial scale chromate recovery systems in the U.S. The chromate recovery system is located in the ethylene plant of the Channelview, Texas, chemical complex. It was designed to treat a 1100 GPM cooling tower blowdown stream containing a 20-25 ppm chromate (CrO, ). A strongbase anion resin is used to selectively remove the chromate. This unit was placed in service in June, 1976. Information presented in this paper is based upon operating experiences. Economic considerations are also included. 

Recovery System (MARS) for recovery of phenol from resin production condensates. Journal of Membrane Science,... 

Recoveiy of solvent vapor (dicfaloromethane, CH2CI2) fiom air by pressure swing adsorption (PSA) was studied, using two columns packed with high silica zeolite and resin as adsorbent Gravimetric measurements wete made for dichloromethane on the adsorbents. Computer calculations were carried out to simulate the experimental results using the Stop-Go method to show the calculated results coincide well with experimental results. The method is useful to predict the performance of a solvent recovery system operated by PSA... 

After these preheat treatment processes, the two treated (cross-linked) PMS resins were pyrolyzed at 1273 K. Resin recovery after preheat treatment and ceramic yield of these cross-linked resins at 1273 K are summarized in Table 19.2. Use of the reflux system is effective to increase resin recovery and ceramic yield. Figure 19.4 shows the overall ceramic yield of the starting PMS with different thermal histories. The dotted line indicates the intrinsic ceramic yield from PMS by direct pyrolysis up to 1273 K (about 30%). The filled circle indicates the ceramic yield at 1273 K with two-step pyrolysis, in which reflux treatment is the first step. Overall ceramic yield begins to increase at 423 to 523 K, and is saturated (approximately 75%) at 623 K. Even when a preheat treatment step on PMS is a simple heat treatment in an open argon gas flow (open circle), the overall... 

Frederico CF, Ludmila PA, Boam SZ, and Andrew L. Pilot scale application of the membrane aromatic recovery system (MARS) for recovery of phenol from resin production condensates. J. Memb. Sci. 2005 257 120-133. 

Spray Drying. The spray drying of aminoplasts requires careful contrd because of the low softening temperature and the hygroscopidty of the resins. Atomization, mr temperature, air pattern in the drier, and the temperature and humidities of the recovery system must be carefully controlled. 

Some concern has been expressed tiiat the Murphy CPBA system for total T4 is not operating optimally as a true satmation analysis and that T4 disequilibrates between TBP and the resin, so that the final result is dependent on the TBP capacity of a serum as well as its total T4 concentration (M2). However, recent studies have indicated that dissociation of the protein-T4 complex is too slow to have a significant effect on the resin separation system (C19). In other words, the use of resins in the CPBA system to separate bound and free T4 is quite valid. Nevertheless, some workers have looked to other media to effect this separation, e.g., Sephadex (C22), but this is not an ideal way, as Sephadex has an affinity for T4 (C19). Columns of Sephadex have also been used to good effect as a substitute for ethanol in separating the T4 from the serum (B14, S7), and such techniques are much simpler than the original and furthermore, result in an almost constant 100 recovery of the T, in the serum compared with the low and variable recovery with ethanol. 

Tetrahydrofuran (THF) is produced by decarbonylation of furfural to furan followed by catalytic hydrogenation. THF is applied as a solvent for resins and plastics, film castings and adhesives. THF also acts as a solvent in different fine organic syntheses on a commercial scale and as a chemical intermediate. Environmental demands increase the THF application cost because THF users must install solvent recovery systems. A high price and environmental considerations will limit the future growth of THF market. 

Decisions made in each of the previous areas influence the layout and sizing of the resin distribution system. It must accommodate all of the requirements of the storage, blending, drying, and scrap recovery operations while taking into account resin characteristics and plant layouts. It is typically one of the final items designed aft er many other system decisions have been made. 

For many fabric recycling processes such as nylon depolymerization and polymer resin recovery, it is desirable or required to sort the feedstock according to the type of fibers. For carpet, the sorting is according to the type of the face fiber. A melt point indicator is an inexpensive instrument that can identily most fiber types, but it is generally slow and cannot distinguish between nylon 6,6 and polyester. Infrared and Raman spectroscopy are much more effective. Table 6.1 compares the various carpet identification systems. ... 

Conifers and some hardwoods containing significant amounts of resinous components are best pulped by the kraft process. The free resin acids and fatty acids are neutralized by the alkali, their esters are saponified, and the alkali is lost in the tail-oil recovery system. 

In many solvent recovery systems, adsorption represents only one step in a complex series of chemical engineering operations. The design of a eomplete system for recovering methylene chloride and methanol from air emitted from a dryer in a resin processing plant has been described by Drew (1975). The overall solvent recovery system includes a water scrubber to remove resins and cool the air to 100°-110°F a standard 2-bed carbon adsorber unit designed for 95% solvent removal efficiency a condenser and decanter to handle the vapors that are stripped from the carbon by steam an extraction column in which water is used to remove the water soluble methanol from the methylene chloride phase a stripping column to remove dissolved methanol and methylene chloride from the waste water and a drying column to remove water from the recovered methylene chloride. These items of equipment and operations are representative of those required for complete solvent recovery systems however, each system must, of course, be tailored to the profierties of the specific solvent involved. 

The PolyMag Additive Process enables the automated separation of mixed resin regrind. This innovative system reduces the cost of waste in multimaterial, co-molding operations. This paper will describe the process and applications for post-industrial resin recovery and recycling. 

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