Of contacting devices

Chen [133] highlights the long-term growth of the technically popular use of bubble cap trays, valve and sieve trays, followed by the increased popularity of packed columns accompanied by the development of random and structured packings. There are some applications in chemical/ petrochemical/petroleum/gas treating processes where one type of contacting device performs better and is more economical than others. Chen [133] points out ... 

Select the type of contacting device plates or packing. 

Over the past 20 years, most of the bubble-cap trays have been replaced by other types of contacting devices. New columns are usually equipped with either valve trays (see Fig. 1-3) or sievilrays (see Fig. 1-1), sometimes called perforated trays. In valve trays, the valve opens wider as the vapor velocity increases and closes as the vapor velocity decreases. This feature of opening and closing allows the valve to remain immersed in liquid and thereby preserve a liquid seal over wide ranges of liquid and vapor flow rates. c 2... 

HL were set in the control circuit, that is, 1 clear water pump Ml, 2 clear water pump M2, indicating lamps HLl, HL2 and HL3 were also set in the aeration air blower M3. The above instruct lights were controlled auxiliary switch of contact device KM 1, KM2 and KM3. The overload protection of M1, M2, M3 and M4 were realized by four thermal relay FRl, FR2, FR3 and FR4. Overload protect was composed by closed-switch of contact KMl and intermediate relay KAl, KAl has also played the role of voltage conversion, the 220 V AC signal was converted into DC 24 V signals, which was sent into the PLC to complete overload control. 

An enormous amount of work has gone into the study of contacting devices, and the literature on their performance characteristics is extensive. Most of the work dealing with laiger equipment has been based on plant observations, but a significant portion of it has been based on controlled experiments in commercial-scale equipment by Fractionation Research, Inc. (FRI). The methods for analysis and design of distillation columns, present in this section, are based on a combination of fundamental research papers, results released by FRI, and many repotted plant tests. 

Various types of contacting devices used for the absorption of chlorine are discussed in Section 9.1.10.3B. Eductors are frequently used with low-pressure chlorine. Emergency vent scrubber columns usually are of lined carbon steel or a PVC7FRP composite. Internals may be rubber-coated or CPVC, and packing usually is ceramic, CPVC, or PVDF rings. Polypropylene is an alternative. 

Different Types of Contacting Devices and Commercial Availability... 

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