Recovery agitation

Maximize slop oil recovery. Agitate sludge with air and steam to recover residual oils. 

Sherwin TS, Green SM, Khan A, Chapman DS, Dannenberg B. Does adjunctive midazolam reduce recovery agitation after ketamine sedation for pediatric procedures A randomized, double-bhnd, placebo-controlled trial. Ann Emerg Med 2000 35(3) 229-38. 

Comparative studies Propofol and ketamine have been compared in procedural sedation in the Emergency Department [34. Patients were randomized to propofol 1+0.5 mg/kg every 3 minutes if needed ( =50) or the same doses of ketamine ( =47). There was a higher rate of subclinical respiratory depression with ketamine, but the number of clinical interventions in the two groups was the same. Recovery agitation was more common with the ketamine group than propofol (17% versus 4%), but procedural pain was less common (2.1% versus 6.0%). Recall and patient satisfaction were similar (13% versus 12% and 100% versus 100%). 

This carbon dioxide-free solution is usually treated in an external, weU-agitated liming tank called a "prelimer." Then the ammonium chloride reacts with milk of lime and the resultant ammonia gas is vented back to the distiller. Hot calcium chloride solution, containing residual ammonia in the form of ammonium hydroxide, flows back to a lower section of the distiller. Low pressure steam sweeps practically all of the ammonia out of the limed solution. The final solution, known as "distiller waste," contains calcium chloride, unreacted sodium chloride, and excess lime. It is diluted by the condensed steam and the water in which the lime was conveyed to the reaction. Distiller waste also contains inert soHds brought in with the lime. In some plants, calcium chloride [10045-52-4], CaCl, is recovered from part of this solution. Close control of the distillation process is requited in order to thoroughly strip carbon dioxide, avoid waste of lime, and achieve nearly complete ammonia recovery. The hot (56°C) mixture of wet ammonia and carbon dioxide leaving the top of the distiller is cooled to remove water vapor before being sent back to the ammonia absorber. 

The pot extractor is a batch extraction plant in which extraction and solvent recovery from the exhausted soHds can be carried out in a single vessel. These extractors are normally agitated vessels having capacities in the range of 2 to 10 m, beyond which the battery system becomes a preferred technical alternative. 

Enclosed agitated filters are useful when volatile solvents are in use or when the solvent gives off toxic vapor or fume. Another significant advantage is that their operation does not require any manual labor. Control can be manual or automatic, usually by timers or by specific measurements of the product. Most filters are made of mild steel, with the exposed surfaces protected by lead, tile, mbber lining, or by coating or spraying with other substances as necessary. Filtration areas up to 10 m are available and the maximum cake thickness is 1 m. Apphcations are mainly in the chemical industry for the recovery of solvents. 

Electrolysis. GalHum can be extracted by direct electrolysis of the aluminate solution at a strongly agitated mercury cathode. The recovery from a sodium gallate solution resulting from the carbonation process is another possibiHty. This process is probably no longer operative because of the environmental problems associated with the mercury. 

A 95% yield of pure anthraquinone was obtained. This is an almost quantitative yield based on the 100% content of the anthracene used. The cmde anthraquinone was then purified. To a jacketed steel kettie, provided with an agitator, was added cmde anthraquinone and nitrobenzene. Under agitation, the charge was heated at 130—140°C until a complete solution resulted. Under slow agitation, the solution was cooled to 30 °C and the resulting slurry of anthraquinone was filtered on a pressure filter. The cake was washed twice with nitrobenzene, then was reslurried on the filter with nitrobenzene, sucked dry, and transferred to a vacuum dryer where the nitrobenzene was distilled. The dried anthraquinone was discharged to suitable containers. A 99% yield of pure anthraquinone was obtained equal to a recovery of approximately 90% based on the cmde anthraquinone. 

Lime-Sulfuric. Recovery of citric acid by calcium salt precipitation is shown in Figure 3. Although the chemistry is straightforward, the engineering principles, separation techniques, and unit operations employed result in a complex commercial process. The fermentation broth, which has been separated from the insoluble biomass, is treated with a calcium hydroxide (lime) slurry to precipitate calcium citrate. After sufficient reaction time, the calcium citrate slurry is filtered and the filter cake washed free of soluble impurities. The clean calcium citrate cake is reslurried and acidified with sulfuric acid, converting the calcium citrate to soluble citric acid and insoluble calcium sulfate. Both the calcium citrate and calcium sulfate reactions are generally performed in agitated reaction vessels made of 316 stainless steel and filtered on commercially available filtration equipment. 

Butyl slurry at 25—35 wt % mbber continuously overflows from the reactor through a transferline to an agitated flash dmm operating at 140—160 kPa (1.4—1.6 atm) and 55—70°C. Steam and hot water are mixed with the slurry in a nozzle as it enters the dmm to vaporize methyl chloride and unreacted monomers that pass overhead to a recovery system. The vapor stream is compressed, dried over alumina, and fractionated to yield a recycle stream of methyl chloride and isobutylene. Pure methyl chloride is recovered for the coinitiator (AlCl ) preparation. In the flash dmm, the polymer agglomerates as a coarse cmmb in water. Metal stearate, eg, aluminum, calcium, or zinc stearate, is added to control the cmmb size. Other additives, such as antioxidants, can also be introduced at this point. The polymer cmmb at 8—12 wt % in water flows from the flash dmm to a stripping vessel operated under high vacuum to... 

The mbber is then separated from its solvent by steam stripping. The viscous cement is pumped into a violently agitated vessel partly full of boiling water. The hexane flashes off and, together with water vapor, passes overhead to a condenser and to a decanter for recovery and reuse after drying. Residual unpolymerized ethylene and propylene appear at the hexane condenser as noncondensibles, and are recovered for reuse after drying. The polymer, freed from its carrier solvent, falls into the water in the form of cmmb. 

In practice, the taffy process is generally employed for only medium molecular-weight resins (1) (n = 1-4). The polymerization reaction results in a highly viscous product (emulsion of water and resin) and the condensation reaction becomes dependent on agitation. At the completion of the reaction, the heterogeneous mixture consists of an alkaline brine solution and a water—resin emulsion and recovery of the product is accompHshed by separation of phases, washing of the taffy resin with water, and removal of water under vacuum. 

Simard et al. [Can. J. Chem. Eng., 39, 229 (1961)]. Continuous extraction of uranium from aqueous nitrate solutions into kerosine -t- trihiityl phosphate and from sulfate solutions containing tricaprylamine unbaffled vessel, propeller agitated. Process details for high recovery and low reagent costs. 

Continuous recovery requires AA crystals having an average diameter of ca. 40-50 nm.5 Such crystals are obtained by continuously introducing die hot hydrolysate containing 10-20% AA into an agitated crystallization vessel while maintaining an average temperature of 20-30°C. The slurry obtained from the crystallization vessel is filtered to collect die AA crystals, and the filtrate which contains the HMDA acid salt is continuously neutralized with calcium hydroxide. The calcium salt formed is removed by filtration, and the HMDA in the filtrate is isolated by distillation. 

A commonly used extraction technique involves shaking soil with a suitable solvent on a mechanical shaker at about 300 rpm. After extraction, the soil extracts are collected by centrifugation followed by decantation or filtration. This technique could be used for any amount of soil samples (from 10 to >100g). Soil samples greater than 100 g require efficient agitation to achieve acceptable recoveries. 

---