Precipitators continuous stirred tank reactors

Subsequent laboratory continuous stirred tank reactor (CSTR) tests showed that in generating the waste solids CaSOi was being precipitated along with the CaSC>3 even though the solution was not saturated with respect to CaSOi. Thus suggesting the possibility that the precipitation of CaSO involved the formation of some sort of solid solution in the CaSC>3 1/2 H2O lattice. 

Figure 4.15 Particle size distribution of protein aggregate in a continuous stirred-tank reactor comparison of model with experimental data. 0.15kg/m A, 300kg/m O, 25.00kg/m. [From The Formation and Growth of Protein Precipitates in a Continuous Stirred-Tank Reactor, C.E. Glatz, M. Hoare, and J. Landa-Vertiz (1987), AIChE J. 32(7), pp. 1196-1204. Reproduced by permission of the American Institute of Chemical Engineers. 1987 AIChE.]...

Herein are reported Mossbauer results obtained for an unpromoted and potassium promoted precipitated iron catalyst that was activated and used for synthesis in a slurry phase, continuous stirred tank reactor at high conversion and under industrially relevant conditions. Strict measures were observed to prevent oxidation of the catalyst samples. The results reported here compare the iron phases present initially and as the two iron catalysts are utilized for FT synthesis. 

In the following discussion, we will detail the results and operational experiences the enhanced SBCR system. Objectives of the ran were to 1) test the new slurry level control system 2) compare the performance of a precipitated Fe/K Fischer Tropsch Synthesis (FTS) catalyst in the enhanced SBCR and a continuous stirred tank reactor (CSTR) and 3) determine the effectiveness of the catalyst/wax filtration system. 

Maruscak, A., Baker, C.G.J. and Bergougnou, M.A. (1971) Calcium carbonate precipitation in a continuous stirred tank reactor. Canadian Journal of Chemical Engineering, 49, 819-824. 

The simplest continuous reactor to consider is that of a constantly stirred tank reactor (CSTR) or precipitator, also called a mixed suspension, mixed product removal crystallizer (MSMPR) [98], shown in Figure 6.23. This tsrpe of precipitator has a constant volume, V, with an input flow rate equal to its output flow rate, Q. The population iJofR) in the precipitator is that which leaves as product. In this case, the population balance is used at steady state (i.e., drjfjdt — 0) ... 

The experimental equipment used in studying the continuous oxalate precipitation and the separation of the precipitate from the liquid is depicted schematically in Figure 3. The equipment allowed for options of filtering or settling the precipitate and the use of either one or two stirred tank reactors. The following variables were studied ... 

Numerous variations of the interfacial process have been published. The reactions can be carried out in batch in stirred tank reactors or continuously in series of CSTRs and tubular reactors. Intensive mixing with dispersion and redispersion is required throughout the reaction stages. After the reaction is complete, the brine phase is separated and the polymer solution washed to remove residual amine and base. Several processes for devolatilization are in use, including solventless precipitation, steam precipitation, spray drying, falling-strand devolatilization, and vacuum extrusion in devolatilizing extruders. 

The slurry from the ERH sump is pumped to one of two continuously stirred reactors (two for each ERH, four for the plant) to complete the hydrolysis, if necessary. Because the sodium hydroxide dissolves any aluminum present in the munitions, converting it to aluminum hydroxide, the aluminum hydroxide is prevented from clogging downstream components by neutralizing the completely reacted hydrolysate with hydrochloric or sulfuric acid, causing the dissolved aluminum to form a precipitate, which is then filtered (Step 7). The hydrolysate is sent to holding tanks to await secondary treatment in the SCWO reactors. 

Processes for precipitation of solid products from dissolved reactants are almost always carried out in stirred tanks. The reactors are operated either semi-batchwise or continuously. In both operation modes, one reactant is added to a stirred solution containing an excess of the other reactant. The functions of the stirrer are mixing of the reactants, suspension of the formed solid particles, and promotion of heat transfer to the wall. 

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