Diluent recovery

Distillation required - energy intensive Low reactor utilization Energy-intensive diluent recovery... 

The treated oil-bitumen is collected in the bottom of the vessel, while the vapors exit at the top. The contact temperature in the vessel is approximately 150 C (300 T), and the total area of the three trays is approximately 3.34 m (36 sq ft). The treated oil, which should contain less than 0.5% (v/v) water, is then pumped from the bottom of the evaporator, fan-cooled and sent to the treated-oil storage tank (T-2). The water-diluent vapors are also fan-cooled, sent to an accumulator, and then transferred to a gravity separator for diluent recovery. Water is sent to the produced-water tank (T-3) before being processed through the IGF unit. 

The current oil sands bitumen upgrading processes for the production of synthetic crude oil (Table 4) begin with diluted bitumen being processed through the diluent recovery units. The diluent recovery units are atmospheric distillation units that serve three purposes 1) distill off diluent naphtha and return it to the froth treatment process 2) distill off light gas oil and send it directly to a light gas oil hydrotreater and 3) produce hot atmospheric topped bitumen as feedstock for vacuum distillation unit and downstream bitumen conversion processes. 

Diluent Although extensive precautions are taken to avoid loss of diluent from the plant, this can never be totally prevented. Apart from the fugitive losses of diluent, a loss occurs in the heavy ends fraction of the diluent recovery operation. Since the LIPP process does not use a diluent except for some flushing, the amount of diluent lost is drastically reduced. 

The Mitsui CX process is typical of a modem slurry process for HDPE production (Figure 2.37). It consists of two CSTRs (hexane is used as diluent), a centrifuge to separate the diluent from the polymer, a dryer to remove the residual diluent, and a diluent recovery system to separate the low molecular weight polymer or wax that is dissolved in the diluent. The two polymerization reactors can be operated in series or in parallel. When run in... 

In this type of process, polymerization takes place in liquid propylene without the use of an inert diluent. This is a significant simplification over the traditional diluent slurry process, as propylene can be separated from the polymer by flashing, and there is no need for the extensive diluent recovery system. 

Good temperature control due to high turbulence and heat-transfer coefficients, and heat removal by the latent heat of vaporization of inerts and monomers. Lower operational costs due to lack of diluent recovery operations and, in the case of fluidized-bed reactors, due to the absence of moving parts. 

This technology accoxmts for an annual production of 4-5 million tons of HDPE. The process involves polymerization of ethylene at temperatures below the melting point of the polymer using a solid catalyst to form solid polymer particles suspended in an inert hydrocarbon diluent. Recovery of polymer (by filtration, centrifugation, or flashing) is economic. The chromium oxide-on-silica catalyst developed by Phillips yields polymers which can be easily extruded and blow-moulded. The process is unable to produce copolymers of density below 0.937 g/cm. For a density of 0.92 g/ cm or below, the polymer swells, becomes sticky, and starts to dissolve in the reaction diluent. 

Vacuum flashing of an effluent from thermal conyersion allows recovery of a distillate that is sent to the FCC and replaced as diluent by a product of lesser quality coming from the FCC, (HCO or LCO). 

The derivatives are hydroxyethyl and hydroxypropyl cellulose. AH four derivatives find numerous appHcations and there are other reactants that can be added to ceUulose, including the mixed addition of reactants lea ding to adducts of commercial significance. In the commercial production of mixed ethers there are economic factors to consider that include the efficiency of adduct additions (ca 40%), waste product disposal, and the method of product recovery and drying on a commercial scale. The products produced by equation 2 require heat and produce NaCl, a corrosive by-product, with each mole of adduct added. These products are produced by a paste process and require corrosion-resistant production units. The oxirane additions (eq. 3) are exothermic, and with the explosive nature of the oxiranes, require a dispersion diluent in their synthesis (see Cellulose ethers). 

If the viscous bitumen in a tar sand formation can be made mobile by an admixture of either a hydrocarbon diluent or an emulsifying fluid, a relatively low temperature secondary recovery process is possible (emulsion steam drive). If the formation is impermeable, communication problems exist between injection and production weUs. However, it is possible to apply a solution or dilution process along a narrow fracture plane between injection and production weUs. 

The polymerization of ethylene can also occur in a liquid-phase system where a hydrocarbon diluent is added. This requires a hydrocarbon recovery system. 

If diluent is being added to the feed, evaluate the optimum point for minimum pressure drop and maximum heat recovery. 

The bacterial culture converts a portion of the supplied nutrient into vegetative cells, spores, crystalline protein toxin, soluble toxins, exoenzymes, and metabolic excretion products by the time of complete sporulation of the population. Although synchronous growth is not necessary, nearly simultaneous sporulation of the entire population is desired in order to obtain a uniform product. Depending on the manner of recovery of active material for the product, it will contain the insolubles including bacterial spores, crystals, cellular debris, and residual medium ingredients plus any soluble materials which may be carried with the fluid constituents. Diluents, vehicles, stickers, and chemical protectants, as the individual formulation procedure may dictate, are then added to the harvested fermentation products. The materials are used experimentally and commercially as dusts, wettable powders, and sprayable liquid formulations. Thus, a... 

A special technique was developed for rare-earth samples in which rapid hydration and carbonation occurred. The rare-earth oxalates were found to be more stable than the oxides and were used as sample material. In the rare-earth processing procedures that include an oxalate precipitate, the oxalate can be used as sample material. The advantages are that no diluent is required, weighing is eliminated, and recovery of the rare earths is simplified. 

Recovery — Recovery control (RC) solutions were prepared in 10/90 v/v ACN/water. Recovery evaluation (RE) samples were prepared in human plasma. Aliquot of RC solutions into assay plates followed sample preparation procedure steps 1 and 2. Instead of adding 50 pL of diluent, wells containing RC solutions were dried down under a steady stream of room temperature N2. The dried wells were then reconstituted with 250 pL of diluent. Reconstituted RC solutions were directly injected onto an HPLC analytical column, bypassing the extraction column. RE samples were aliquoted into an assay plate following normal sample preparation. RE samples were analyzed using the full extraction procedure (with extraction column). The analyte was tested at three concentration levels and the internal standard was tested at one. Mean extraction recovery for fenofibric acid varied from 93.2 to 111.1%, and mean extraction recovery for the Pestanal internal standard was 105.2%. 

Microbial recovery studies of membrane filtration method challenged with less than 100 CPU of each organism listed in USP-25, EP-2002 and in-house microbial isolates. Two lots of (Product Name) (Batch Numbers) have been validated in triplicate for each organism. Validation mimicked the test proper in every detail, such as in the volumes of media used, quantities and dilutions of product and diluents. 

This method is applicable both for ancillary and main recovery. For the latter, however, a closed cycle is avoided by introducing large amounts of fresh air into the driers, as a diluent. 

The Purex process, ie, plutonium uranium reduction extraction, employs an organic phase consisting of 30 wt % TBP dissolved in a kerosene-type diluent. Purification and separation of U and Pu is achieved because of the extractability of U02+2 and Pu(IV) nitrates by TBP and the relative inextractability of Pu(III) and most fission product nitrates. Plutonium nitrate and U02(N03)2 are extracted into the organic phase by the formation of compounds, eg, Pu(N03)4 -2TBP. The plutonium is reduced to Pu(III) by treatment with ferrous sulfamate, hydrazine, or hydroxylamine and is transferred to the aqueous phase U remains in the organic phase. Further purification is achieved by oxidation of Pu(III) to Pu(IV) and re-extraction with TBP. The plutonium is transferred to an aqueous product. Plutonium recovery from the Purex process is ca 99.9 wt % (128). Decontamination factors are 106 — 10s (97,126,129). A flow sheet of the Purex process is shown in Figure 7. 

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