Batch recycle

Appropriate setting of two on-off valves (Fig. 1) allows the system to be operated either as a batch recycle reactor or as a continuous-flow steady-state recycle reactor. 

OS 46] ]R 18] ]P 34] The initial yield of batch-recycle processing was 96% (micro mixer 93%) and the yield of the second recycle process was 80% (micro mixer 83%) [120]. Hence the yields were comparable. For the batch recycling, the yields of the third and fourth runs were also determined, being 78 and 63% (no micro mixer data here). 

Korbach and Stewart [Ind. Eng. Chem. Fundamentals, 3 (24), 1964] have studied the vapor phase hydrogenation of benzene in a batch recycle reactor. 

The catalyst components are generally dissolved in methyl acetate which acts as both reactant and solvent. Other solvents may be used and in fact, upon several batch recycles where lower boiling products are distilled off, the solvent is an ethylidene diacetate-acetic acid mixture. Any water introduced in the reaction mixture will be consumed via ester and anhydride hydrolysis, therefore anhydrous conditions are warranted. Typical batch reaction examples are presented in Table 1. There is generally sufficient reactivity when carbon monoxide and hydrogen are present at 200-500 psi. Similar results were obtained from the pilot plant using a continuous stirred tank reactor (CSTR). The reaction can also be run continuously over a supported catalyst with a feed of methyl acetate, methyl iodide, CO, and hydrogen. 

Hydrogenation runs were carried out in a dead-end 300 cm3 batch autoclave manufactured by Autoclave Engineers, Erie, Pa. Description of the experimental setup has been given elsewhere (Ref. 8). The batch -recycle... 

Oxidation of hydrogen on a Pt/alumina particle in a batch recycle-flow reactor liraCek et al. (23) X... 

ELECTRODIALYTIC BATCH RECYCLE RECOVERY OF A FEW SODIUM SALTS OF LACTIC, ITACONIC, AND CITRIC ACIDS FROM AQUEOUS SOLUTIONS AT DIFFERENT pH VALUES AND 33"C ... 

Most of the experiments were carried out in a pilot-scale reactor (Fig. 8.25). For each experiment, four pieces of coated monoliths were stacked carefully in line and mounted in a 2 m- high heated column of 50 mm diameter. The preheated liquid feed was distributed via a spray nozzle. After each pass, the liquid was collected in the liquid-supply vessel and was circulated continuously through the reactor (batch-recycle mode). The preheated countercurrent nitrogen stream was fed after one pass to a condenser to separate the liquid, and then vented. The condensables were collected in a phase separator, from where the water could be tapped off, whilst the... 

The reactor can be operated in a batch recycle mode. One of the advantages of SPE HDH technology is that separation and recycling of a supporting electrolyte are unnecessary, which can greatly reduce process cost. 

Fig. 19.9 Sketch of the flow undivided electrochemical reactor working in batch recycle mode designed for the hydroxylation of chlorobenzene and phenol (Hsiao et al. 1993)...

Drain the high-boiling residue and get ready for next batch recycle the center cut and prepare to charge fresh feed 3 h... 

Figures 22a, b provides a schematic representation of the pilot scale reactor. Essentially it is a rectangular parallelepiped limited by two parallel windows made of borosilicate glass and operated as a slurry reactor inside the loop of a batch recycling system. Irradiation of one of the reactor faces is obtained using two tubular lamps that were placed along the focal axis of two parabolic reflectors made of specularly finished aluminum (Brandi et al., 1996, 1999, 2002). The specific information concerning the experimental device is presented in Table 9, and more details can be found in Satuf et al. (2007b).

Simulating batch and semicontinuous processes to determine rate-controlling steps and investigate batch-to-batch recycles and heat recovery ... 

Using a batch recycle mode, oily wastewater was treated in the photoassisted advanced oxidation systems. Their results indicated that UV/H2O2 oxidized oily compounds into organic acids with the efficiency being greater at acidic pH. The oxidation rate was enhanced in the presence of Fe " ". 

A. E. Cassano, T. Matsuura, and J. M. Smith, Ind. Eng. Chem., Fund. Quart., 7, 655 (1968). Fig. 12-1 Batch recycle reactor of tubular-flow type... 

A batch recycle reactor (Fig. 12-1), operated differentially and used for the gas-phase photolysis of acetone, has a volume of 62.8 cm, while the total volume of the system is 6,620 axr. Runs at 97°C and 870 mm Hg pressure were made at different initial concentrations of acetone in helium. Typical data for conversion to C2H6 are as given below for varying initial concentrations (gram moles per liter). The products of photolysis are primarily CjHe and CO, according to the overall reaction... 

Table 4 Catalyst Activity (mmol H2) in Batch Recycle 140°/400 psig/65 mg(1.86% loading)... 

With feed and bleed or batch recycle systems some or all of the water that has already been processed by the stack is mixed with feed and returned via a recirculation pump. Recycle is inherently less efficient than once-through flow in both stack utilization and in energy consumptions since the same solution must be pumped and desalted repeatedly and then remixed with a more concentrated solution. However, the increased flexibility in process control makes recycle systems attractive for small-scale operations where stacks are over-sized to handle varying loads. Feed and bleed is useful for operations where the enriching stream needs to be as concentrated as possible. Ten-fold enrichment or 90% recovery of some feed waters as diluate can be achieved by concentrate recirculation if solubility limits of the dissolved substances are not exceeded in the concentrate stream. 

DiGiano (1996) suggested a batch-recycle membrane test as an alternative. The test operates in batch mode by recirculating both feed and permeate. The advantage of this test is the lower feed volume required (3 L versus 60 to 200 L for the RBSMT). Moulin (1993) described a dynamic membrane test, that allows determination of the suitability of a membrane to obtain the required health standards (cytotoxicity). 

DiGiano F.A, (1996), Evaluation of Natural Organic Matter Fouling in Bench-scale, Batch Recycle Tests of Nanofiltration, ICR Workshop on Bench-scale and Pilot-scale Evaluations, AWAVA, Cincinnati, Ohio, March 1996. 

Electrochemical flow cells commonly suffer from the problem that the conversion per pass is low. Eor this reason, it is common to run such cells with an electrolyte reservoir and to recirculate the electrolyte repeatedly through a cell or group of cells and back to the reservoir. If the electrochemical process including the flow cell is operated batchwise, it is known as a batch recycle process (Figure 17.4a). The reagent concentration in the reservoir decreases with time and the process is stopped when... 

The batch recycle differential reactor is used to obtain adsorption rate data to evaluate various kinetic models for cadmium ion adsorption on Sol-AD-lV. Approximately 0.25 g of the solid extractant is placed between glass beads inserted in a glass tube of 1.0 cm internal diameter. Solutions of various cadmium ion concentrations (25 to 300 mg/1) are contacted in a batch mode over 720 minutes, with intermediate sample taken for atomic absorption spectroscopic measurements of the cadmium ions. The external mass transfer resistances are minimized by operating at 16 ml/min. Results of the experiments are shown in Figure 7.23. 

FIGURE 7.23 Kinetic data of Cd + adsorption on Sof-AD-IV with batch recycle differential reactor. (From J. S. Lee, S. Gomez-Salazar, and L. L. Tavlarides. Reactive and Functional Polymers 49 159-172, 2001. With permission.)... 

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