Bleed stream

In the one-stage process (Fig. 2), ethylene, oxygen, and recycle gas are directed to a vertical reactor for contact with the catalyst solution under slight pressure. The water evaporated during the reaction absorbs the heat evolved, and make-up water is fed as necessary to maintain the desired catalyst concentration. The gases are water-scmbbed and the resulting acetaldehyde solution is fed to a distUlation column. The tad-gas from the scmbber is recycled to the reactor. Inert materials are eliminated from the recycle gas in a bleed-stream which flows to an auxdiary reactor for additional ethylene conversion. 

The reaction is initiated with nickel carbonyl. The feeds are adjusted to give the bulk of the carbonyl from carbon monoxide. The reaction takes place continuously in an agitated reactor with a Hquid recirculation loop. The reaction is mn at about atmospheric pressure and at about 40°C with an acetylene carbon monoxide mole ratio of 1.1 1 in the presence of 20% excess alcohol. The reactor effluent is washed with nickel chloride brine to remove excess alcohol and nickel salts and the brine—alcohol mixture is stripped to recover alcohol for recycle. The stripped brine is again used as extractant, but with a bleed stream returned to the nickel carbonyl conversion unit. The neutralized cmde monomer is purified by a series of continuous, low pressure distillations. 

Uranium is subsequendy stripped reductively from the loaded solvent using a bleed stream of the raffinate acid to which ferrous iron has been added to reduce uranium to its nonextractable, quadravalent state. Raffinate is acid from which uranium has already been extracted. By controlling the organic-to-aqueous volume phase ratios in the extraction and stripping circuits, uranium is concentrated by a factor of approximately 70. 

The turbine applied to driving mechanical equipment is not operated (very often) with extraction or bleed streams. Here again, this depends upon the plant steam balance, and this is one of the fine features of steam turbine drive. The flexibility of design and application allow it to be set in the proper place for the economic balance of a system. The decision as to condensing or noncondensing should not be... 

Refining operations have two principal wastestreams, waste electrolyte and cathode and anode washwater. Spent electrolyte is normally recycled. A bleed stream is treated to reduce copper and impurity concentration. Varying degrees of treatment are necessary because of the differences in the anode copper. Anode impurities, including nickel, arsenic, and traces of antimony and bismuth, may be present in the effluent if the spent electrolyte bleed stream is discharged. Tables 3.14 and 3.15 present classical and toxic pollutant data for raw wastewater in this subcategory. 

A bleed stream from the absorption part of the process is dewatered and dried. The crystals of magnesium sulfite and magnesium sulfate are then calcined solid magnesium oxide is returned to the scrubbing process, and sulfur dioxide which is released with the calcination is then converted into a salable product such as sulfuric acid. 

After the zinc has been removed, the sulfuric acid rich solution is returned to dissolve the next batch of sludge. Over time, the sodium concentrations will read unacceptable levels in the electrolyte. A bleed stream from the zinc cells is constantly being neutralized and filtered. The saturated sodium sulfate solution thus created is crystallized out as sodium sulfate anhydrous for sale to the pulp and paper industry. Table one shows a complete mass balance for a typical batch. 

The Sumitomo Metal Mining Co. in Japan uses a 40% solution of tri- -octylamine in xylene to separate cobalt and nickel in chloride media.44-163 194 The traces of zinc that are present are coextracted with the cobalt and, owing to the strong extraction of zinc, remain in the organic phase when the cobalt is stripped with water (cf. Figure 11). The zinc is then removed from a bleed stream of the organic phase by deprotonation stripping with sodium hydroxide solution ... 

If all cells are recycled back into the fermenter, the cell concentration will increase continuously with time and a steady state will never be reached. Therefore, to operate a CSTF with recycling in a steady-state mode, we need to have a bleeding stream, as shown in Figure 6.19. The material balance for cells in the fermenter with a cell recycling unit is... 

No one as yet has developed an algorithm suitable for a general separation problem rtiich uses flash units, bleed streams, mixers, etc., as well as "list splitter" columns in the solution. Such an algorithm would have to handle partial splits. At best the algorithms for a total flowsheet might give an approach but not a solution to this much more general problem. 

Consider gaseous purges or liquid bleeds if some components tend to accumulate in recycles. Minimize purge and bleeding streams. 

Calculate outlet flow rates for impurities in purge or bleed streams. 

The excess of reactant at the reactor inlet should be realized by means of recycles, and not by feeding fresh reactant above the stoichiometric ratio. If an excess of reactant is imposed by technological reasons, this part must be removed in purge or bleed streams and becomes an optimization variable. 

The tar and liquor plant handles the flushing liquor that circulates between the byproduct plant and the primary cooler. It also processes the wastewater that results from recovery of the coal moisture and chemically bound water in the coal. The flushing liquor flows into tar decanters, where the tar separates from the water and is pumped to storage for later sale. Heavier solid particles separate from the tar and are removed as tar decanter sludge. After withdrawal of a bleed stream that contains ammonia, the aqueous liquor is pumped back to the primary cooler. Following removal of tar particles, the wastewater stream is steam stripped. An alkali, such as sodium hydroxide, is added to decompose ammonia compounds dissolved in the liquor. The ammonia vapor is recovered and combined with the rest of the ammonia recovered from the coke-oven gas. 

The total gas stream to a reactor unit is 5000 scfh of fresh feed, 12,500 scfh of recycle, and 100 scfh for an instrument bleed stream. If the standard deviation of each measurement is 5 percent of the individual flow, what are the 95 percent... 

Bulky polyaromatic molecules tend to concentrate in recycle streams and are known to be prime coke precursors, as demonstrated in model studies by Latif (60). However, by means of a relatively small bleed stream, the concentration of these polyaromatic species can be contained at a low level, thereby minimizing their deleterious effect on catalyst stability. Alternatively, they can be substantially removed by adsorption on an active-carbon column. 

Description The flowsheet shown is only one of several possible schemes. The raw materials to a free-standing glycol plant are refined ethylene oxide and pure water. These are mixed with recycle waters and pumped from a feed tank (1) to the hydration reactor after being preheated with hot recycle water and steam. When the glycol unit is part of a combined oxide/glycol plant, it is economically desirable to feed it bleed streams from the ethylene oxide... 

The equilibrium relationship between the various reactor components and water will be the important design factor in this unit. Physical and thermal data for all the flow streams will be needed. Build up of inerts is controlled by a bleed stream. The composition of the latter must be known to determine the requirements for in auxiliary reactor designed to complete the oxidation of unconverted ethylene. 

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