Laboratory Scale Reactor

Our ultimate objective is to produce automatically with laboratory-scale reactors polymers with pre-defined molecular characteristics in reasonable amounts for test purposes. Whatever control is exercised over the chemistry of a polymerization to introduce novel structural features into polymer chains, the final molecular weight distribution (MWD) of the product is always of importance hence attention has been given to... 

Another advantage of the micro-LC approach is that the required sample size is minimal, so the sample can be drawn from a 1-1 laboratory scale reactor without influencing the reactor composition. The ISCO pLC-500 microflow syringe pump has proven to be reliable and reproducible in evaluations in our laboratory. Capillary liquid columns have been fabricated on planar devices such as silicon to form a miniaturized separation device.19... 

Apparatus. Since all the polymer modification reactions presented in this paper involved gas consumption, an automated gas consumption measuring system was designed, fabricated and used to keep constant pressure and record continuously the consumption of gas in a batch type laboratory scale reactor. Process control, data acquisition, and analysis was carried out using a personal computer (IBM) and an interface device (Lab-master, Tecmar Inc.). 

Thus, for this reaction, a substantial temperature difference exists between the solid surface and the bulk fluid. It has a far greater influence on the observed rate than the corresponding concentration difference. Differences of this magnitude can clearly lead to complications in the analysis of data obtained in laboratory scale reactors. If such differences will exist at the operating conditions to be employed in a commercial scale reactor, the design engineer must be sure to take them into account in his analysis. 

Coughlin MF, Kinkle BK, Bishop PL (2003) High performance degradation of azo dye Acid Orange 7 and sulfanilic acid in a laboratory scale reactor after seeding with cultured bacterial strains. Water Res 37 2757-2763... 

Laboratory Scale Reactors Involving Probe Systems... 

Laboratory-Scale Reactors. Laboratory-scale sterns consisted of small continuously stirred tank reactors (CSTR) with 3.5-liter worlong volumes and were constructed and operated as previously described (62). The digester inoculum for these systems was obtained from the anaerobic digestion of municipal sewage sludge from the Denver... 

The results remained irregular during this entire period and lacked reproducibility. An important progress however was that during this time my associate Stern developed a laboratory scale reactor which made it possible to work easily at pressures of a hundred odd atmospheres, a reactor of which we soon had two dozens and more in continuous... 

The effectiveness of a fixed-bed operation depends mainly on its hydraulic performance. Even if the physicochemical phenomena are well understood and their application in practice is simple, the operation will probably fail if the hydraulic behavior of the reactor is not adequate. One must be able to recognize the competitive effects of kinetics and fluid dynamics mixing, dead spaces, and bypasses that can completely alter the performance of the reactor when compared to the ideal presentation (Donati and Paludetto, 1997). The main factor of failure in liquid-phase operations is liquid maldistribution, which could be related to low liquid holdup in downflow operation, or other design problems. These effects could be critical not only in full-scale but also in pilot- or even in laboratory-scale reactors. 

The surface to volume ratio of a laboratory-scale reactor is many times greater than that of a plant-scale reactor. This has two effects -... 

Any heat losses from the sample, either into the environment or the test vessel wall, act to reduce the sample temperature. This can lead to a serious underestimation of the rate of reaction. The final temperature attained by the runaway will be less in the laboratory-scale reactor than at plant-scale, and this could cause other reactions (such as decompositions) to be missed entirely on the smaller scale. See Figure A2.1. 

Tertiary screening or traditional laboratory-scale reactors are used to evaluate the secondary leads. Depending on the richness of the data generated in the secondary screen, the tertiary screen may be focused on more complete analysis, or may be focused on other aspects of catalyst performance such as lifetime, susceptibility to poisons, or hydrodynamics. 

For the present case study, a 16-channel laboratory-made parallel reactor was used (Fig. 10.6). Other laboratory-scale reactors were also used with the same libraries to check the specificity of each testing system [13]. 

PACKED BED PLUG-FLOW CATALYTIC REACTOR 9.8.1 Laboratory Scale Reactor... 

Due to the strong interaction between the physical and chemical mechanisms, particularly when catalyst deactivation is present, the parameter estimation becomes very difficult. The kinetic parameters are normally obtained from laboratory scale reactors and when used in pilot plant studies, have to be tuned (1, 2) or even re-evaluated (3, 4) to obtain reasonable predictions. The transport parameters are estimated... 

One of the first fluidized bed photocatalytic reactors was presented by Dibble and Raupp (1992), who used silica-supported titania catalysts in order to degrade TCE with an AQE of 13%. Here, the UV sources in this bench-scale reactor were located externally to the reactor. Catalyst loss was prevented in this laboratory-scale reactor by introducing a second glass frit located at the reactor outlet. 

The segmented reactor is not an ideal reactor for intrinsic kinetic measurements. because gas-liquid and the interparticle resistances in this reactor are difficult to eliminate. However, the laboratory-scale reactor can duplicate the... 

As an example, the experimental data using stirred semi-batch laboratory-scale reactor [7] was obtained from the catalytic degradation of various plastics over spent FCC... 

The large-scale operation should be conceptually built first, considering all requirements necessary to produce products in an industrial operation. The shape and nature of the substrate, e.g., continuous sheet of film or fibers, large or small disks, etc., dictate what kind of operation could be feasible in the industrial scale operation. From the conceptual operation, the key factors of LCVD process should be extracted, and then a laboratory scale reactor should be designed and constructed. In other words, a specific laboratory reactor should be built for a specific industrial scale operation. When this approach is followed, the scale-up of a successful laboratory operation is actually the scale-back to the original conceptual operation. 

On the scale-back process, the key factor is to not change the luminous gas phase as much as possible, which could be done by multiplying the unit process in the laboratory scale reactor in a larger volume vessel, instead of increasing the size of the unit process, e.g., the size of electrodes, the distance between electrodes, and so forth. 

In addition to the laboratory-scale reactors described here, there are numerous more specialized reactors in use. However, as mentioned previously, the performance of these reactors must lie somewhere between the mixing limits of the PFR and the CSTR. Additionally, when using small laboratory reactors, it is often difficult to maintain ideal mixing conditions, and the state of mixing should always be verified (see Chapter 8 for more details) prior to use. A common problem is that flow rates sufficiently large to achieve PFR behavior cannot be obtained in a small laboratory system, and the flow is laminar rather than turbulent (necessary for PFR behavior). If such is the case, the velocity profile across the reactor diameter is parabolic rather than constant. 

Metal- and alloy-containing membranes are currently applied mainly in ultrapure hydrogen production. Pilot plants with palladium alloy tubular membrane catalyst were used in Moscow for hydrogenation of acetylenic alcohols into ethylenic ones. In the Topchiev Institute of Petrochemical Synthesis, a laboratory-scale reactor of the same type was tested... 

TCS synthesis laboratory scale experiments generally yield higher TCS selectivities than do industrial reactors, because of the more defined conditions over the whole of the reacting silicon bed in the laboratory scale reactor. The TCS selectivity losses in the industrial reactor result from regions of imperfect fluid-bed conditions, with significantly increased temperature and significantly lower HCl flow rate than desired. 

As mentioned earlier, both chemical (catalyst, surfactants, stabilizers) and physical (fluid dynamics, energy dissipation rates, circulation time and so on) factors control the performance of the suspension polymerization reactor. It is first necessary to examine the available experimental data to clearly understand the role of these chemical and physical factors. The available data indicates that the yield of usable polymer beads in laboratory scale reactor is more than 85%. Laboratory experiments were then planned to examine the sensitivity of the yield to various parameters of the polymerization recipe under the same hydrodynamic conditions. These experiments showed that the yield is relatively insensitive to small deviations in the chemical recipe. Analysis of the available data on pilot and plant scale indicated a progressive decrease in the yield of usable polymer beads from laboratory to pilot to plant scale. This analysis and some indirect evidence suggested that it may be possible to re-design the plant-scale reactor hardware to generate better fluid dynamics and mixing to increase the yield of particles in the desired size range. 

LWS laboratory scaled reactor, TWS-1 pilot plant, TWS-2 pilot plant for whole tyres, PE polyethylene, + trace detection... 

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