Pulsed tubular reactors

Reflecting the importance of continuous emulsion polymerization processes, numerous investigations have been carried out to date, which are categorized into three groups (1) studies on the reactor configuration (stirred-tank reactors, tubular type reactors such as a simple tubular reactors, pulsed tubular reactors... 

Figure 8.9 Residence time distribution (RTD) for a pulsed tubular reactor. Average residence time = 60 min, with a pulsation rate of 99 spm. C is a dimensionless concentration of a non-reactive tracer solid line is experimental data dashed line is theoretical laminar-flow RTD. [23]...

Pulsed tubular reactor Styrene emulsion polymerization 174... 

Experiments were carried out in a pulse reactor system based on the TAP-2 reactor described by Cleaves et al. [3]. This consists of a small tubular reactor and a detector housed in a vacujun system pumped by a 1,500 Is" turbomolecular pump to a base pressure of... 

The tubular reactor consists of a stainless steel tube (3/8 OD) in which approximately 300 mg of 2% Rh/Al203 is held in place with glass wool and 22 mg of catalyst is loaded in DRIFTS cell. The temperatures are monitored with a K type thermocouple connected to an omega temperature controller. Both pulse and step reaction studies were carried out at 250 °C. 

The responses of this system to ideal step and pulse inputs are shown in Figure 11.3. Because the flow patterns in real tubular reactors will always involve some axial mixing and boundary layer flow near the walls of the vessels, they will distort the response curves for the ideal plug flow reactor. Consequently, the responses of a real tubular reactor to these inputs may look like those shown in Figure 11.3. 

The micro-mixer is supplied continuously with two carrier fluids, either two immiscible liquids or a gas and a liquid. During screening, pulses of the dissolved catalyst to be screened and the substrate are injected simultaneously by a pipetting robot. The pulses are then mixed in a micro-mixer and form short defined reacting segments that move along the tubular reactor. 

Due to the lack of published data on the special flow field generated in the LDPE tubular reactor by the end pulsing valve, the development of the mathematical model was preceded by a fluiddynamic study, with the aim of evidencing the influence, if any, of the pulsed motion on the axial mixing, the heat transfer coefficient and the pressure drop in the reactor. 

To illustrate the concepts of determining, non-determining and negligible processes, the mechanism of the pyrolysis of neopentane will be discussed briefly here. Neopentane pyrolysis has been chosen because it has been studied by various techniques batch reactor [105— 108], continuous flow stirred tank reactor [74, 109], tubular reactor [110], very low pressure pyrolysis [111], wall-less reactor [112, 113], non-quasi-stationary state pyrolysis [114, 115], single pulse shock tube [93, 116] amongst others, and over a large range of temperature, from... 

Description The clean tubular reactor (CTR) process is characterized by a nonfouling reactor for all grades. This is realized without pressure pulsing hence, constant pressure and temperature profiles produce a more consistent and better quality product. Also, the absence of mechanical fatigue and decompositions are important features. 

To illustrate how dispersion affects the concentration profile in a tubular reactor we consider the injection of a perfect tracer pulse. Figure 14-3 shows how dispersion causes the pulse to broaden as it moves down the reactor and becomes less concentrated. 

P14-7j A tubular reactor has been sized to obtain 98% conversion and to process 0.03 mV s. The reaction is a first-order irreversible isomerization. The reactor is 3 m long, with a cross-sectional area of 25 cm. After being built, a pulse tracer test on the reactor gave the following (data t = 10 s and = 65 s. What conversion can be expected in the real reactor ... 

The methanol synthesis activities of Samples 1-6 were determined before, during and after pulsing H2S end are tabulated in Table I. All the samples except 3 were in a single-pass tubular reactor. Sample 3 was tested in an internal recycle reactor, the amount of which (5 cm ) was about five times of those tested in the tubular reactor. For the same amount of fresh feed and pulsed H2S, the methanol yield of Sample 3 and its sulfur content were much lower than those of other samples. The typical effect of pulsing H2S to the feed gas stream is... 

In order to improve the flow characteristics through the tubular reactor, 10 lengths (each 50 cm) of static mixer elements were inserted at 100 cm internals along the tube. Residence-time distribution studies using a pulse of potasiun chloride as tracer shewed that this tubular reactor had the flow characteristics equivalent to a cascade of 35 stirred tanks in series. Thus for practical purposes, this tube can be considered to have flow characteristics equivalent to those of a plug flow reactor. 

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