Raffinate condensation

Feedstock Reactions Catalyst References Acetone Condensation-hydrogenation (bifunctional catalysis) Pd on sulfonated PS-DVB [6] Methanol, Raffinate II Condensation, hydrogenation Pd on sulfonated PS-DVB [61] Dioxygen dissolved in water Hydrogenation Pd on sulfonated PS-DVB [8]... 

The aromatics-laden solvent leaves the bottom of the column as a liquid. The vapors leaving the top of the column, the aromatics raffinate, have almost no aromatics left. They are cooled and condensed to a liquid and used elsewhere, normally as a gasoline blending component. 

The anolyte is evaporated to increase the chloride concentration from 75-250 gdm and cobalt, and most of the iron, is then extracted by the organic solvent. The nickel containing raffinate is diluted by condensate from the evaporation and returned to the Ni-cathode compartments in the diaphragm electrolytic cells for precipitation of nickel. Stripping of cobalt from the organic solvent is performed with the weakly acidic condensate. The strip liquor is fed to the Co-cathode compartment in the electrolytic cells. 

Process modihcations use tetraethylene glycol as the extraction solvent and a mixture of light aliphatics and benzene as the wash solvent to the main extractor. Water condensate from the steam distillation is used to extract residual solvent from the raffinate and extract streams, so distillation for drying the extraction solvent is eliminated. Solids are removed from the recycled extraction solvent by filtration, while acids and high molecular weight fractions are removed by a solid adsorbent bed. Obviously, these processes are expensive and complicated. Most of the effort focuses on the recovery and not on the extraction. 

The extract is pumped from the bottom of D-l to a stripper D-2 with 35 trays. The stripped solvent is cooled with water and returned to D-l. An isoprene-acetonitrile azeotrope goes overhead, condenses, and is partly returned as top tray reflux. The net overhead proceeds to an extract wash column D-3 with 20 trays where the solvent is recovered by countercurrent washing with water. The overhead from D-3 is the finished product isoprene. The bottoms is combined with the bottoms from the raffinate wash column D-4 (20 trays) and sent to the solvent recovery column D-5 with 15 trays. 

The raffinate phase containing asphalt and a small amount of solvent flows from the bottom of the rotating disc contactor to the asphalt mix heater. The hot, two phase asphalt mix from the heater is flashed in the asphalt mix flash tower where solvent vapor is taken overhead, condensed, and collected in the low pressure solvent receiver. The remaining asphalt mix flows to the asphalt stripper where the remaining solvent is stripped overhead with superheated steam. The asphalt stripper overhead vapors are combined with the overhead from the deasphalted oil stripper, condensed, and collected in the stripper drum. The asphalt product is pumped from the stripper and is cooled by generating low pressure steam. 

Description Hydrocarbon feed is preheated with hot circulating solvent and fed at a midpoint into the extractive distillation column (EDC). Lean solvent is fed at an upper point to selectively extract the aromatics into the column bottoms in a vapor/liquid distillation operation. Nonaromatic hydrocarbons exit the column top and pass through a condenser. A portion of the overhead stream is returned to the column top as reflux to wash out any entrained solvent. The balance of the overhead stream is the raffinate product, requiring no further treatment. 

Kvaerner Prcess Technology/ Union Carbide Corp. 2-Propylheptanol Raffinate 2 Rhodium-catalyzed, low pressure oxo process uses improved aldol condensation step 1 1994... 

MTBE separation in practice, this section has only one distillation column, operating under pressure so as to use a water-cooled condenser. It separates MTBE at the bottom, and methanol and unconverted C4. at the top. This is because the azeotropes formed by these hydrocarbons with alcohol have boil ing points lower than that of the azeotrope formed by methanol and ether. The latter has a boiling point of 51.6 C at 0.1 10 Pa. Its weight composition for each of its components is 14 and 86 per cent (30 to 70 at 0.8.10 Pa). Raffinate treatment this section comprises two-step water scnibltiag of the raffinate to remove the methanol, followed by fractionation of the water/methanol mixture. The alcohol recovered is recycled to the reactor. 

Dehumidification is the removal of a solute liquid vapor from a gas phase by the solute condensing into its liquid phase. The removal of water vapor in air by condensation on a cold surface is dehumidification. The reverse of dehumidification is humidification. In this unit operation, the flow of the solute is from the liquid phase evaporating into the gas phase. The end result of this movement is saturation of the gas. For example, during heavy rains, the atmosphere may become saturated with water vapor, the degree of this saturation being measured by the relative humidity. Liquid extraction is the removal of a solute component from a liquid mixture called the raffinate using a liquid solvent. In this operation, the solvent preferentially dissolves the solute molecule to be extracted. 

Raffinate-2 as a raw material is converted to C5 aldehydes and finally to Cio alcohols by sequential hydroformylation, aldol condensation, and hydrogenation [268]. Union Carbide and Davy Process Technology have developed a hydro-... 

It Is possible, of conrse, that the solvatu might be less volatile than the raffinate and more volatile than the extract, or vice versa. In any event, the total fuel equivalent is determined by ndding the appropriate subeel of Eqs, (22.2-9)-(22.2-12), These equations assume thet ihe overhead condensers in the recoveiy distillations accrue neither penalty (refrigamtion) nor credit (hent recovery), If this is not the case, the appropriate adjustments may be made in the manner described in the paragraphs on distillation. 

In liquid-liquid extraction the solvent must nearly always be removed from the extract or raffinate or both. Thus auxiliary stills, evaporators, heaters, and condensers form an essential part of most extraction systems and often cost much more than the extraction device itself. As mentioned at the beginning of this section, if a given separation can be done either by extraction or distillation, economic considerations usually favor distillation. Extraction provides a solution to problems that cannot be solved by distillation alone but does not usually eliminate the need for distillation or evaporation in some part of the separation system. 

Solvent extraction (3) Liquid-liquid extraction is used to separate water and AA. The top of the extractor is forwarded to a solvent separator. The extractor bottom Is sent to the raffinate stripper (5) to recover solvents. Crude acrylic acid (CAA) is separated from the solvents by distillation. The overhead vapor is condensed in an internal thermoplate condenser. The two-phase condensate is separated. The organic phase is recycled. The aqueous phase is sent to the raffinate stripper (5). The column bottom, mostly AA and acetic acid, is routed to the CAA separator (4). 

In the butene isomerization section (1), raffinate-2 feed from OSBL is mixed with butene recycle from the butene distillation section and is vaporized, preheated and fed to the butene isomerization reactor, where butene-2 is isomerized to butene-1 over a fixed bed of proprietary isomerization catalyst. Reactor effluent Is cooled and condensed and flows to the butene distillation section (2) where it is separated into butene-1 product and recycle butene-2 in a butene fractionator. Butene-1 is separated overhead and recycle butene-2 Is produced from the bottom. The column uses a heat-pump system to efficiently separate butene-1 from butene-2 and butane, with no external heat Input. A portion of the bottoms is purged to remove butane before it is recycled to the isomerization reactor. 

During the decontamination steps, acid streams containing small amounts of actinides and fission products are produced. These streams are evaporated to concentrate the metal ions and recycle them. Nitric acid is recovered from the condensates and recycled. Excess HNO3 may be destroyed by formaldehyde. Fission product concentrates are routed to the aqueous raffinate of the first extractor of the partitioning cycle which contains > 99% of the FP. This constitutes the high level liquid waste (HLLW, or alternatively called HAW, high active waste). All other liquid wastes can be subdivided into intermediate level waste... 

Definition Complex bik. solid obtained by blowing air through a heated residuum or raffinate from a deasphalting process with or without a catalyst process is principally one of oxidative condensation which increases the m.w. 

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