Mixer heat exchanger

The methods of mechanical micromachining and micro EDM have been extensively applied to the fabrication of components such as micro heat exchangers, mixers, and reaction channels as well as chemical microsystems with integrated heat exchange, reaction, mixing, and distribution elements (Figure 10). 

One optimum requires a uniformly distributed entropy production rate in a heat exchanger, mixer, or separator. Consider the example of countercurrent and cocurrent heat exchangers shown in Figure 4.11. Temperature profiles... 

In micro-process technology, micro-structured process components such as heat exchangers, mixers or reactors are being developed in which very intensive heat and mass transfer can be realized. In many cases, under defined conditions, this allows process intensification with drastically reduced residence times for the reacting components and simultaneously a considerable increase in selectivity and yield. Due to the low degree of hold-up, hazardous components can be handled safely, even under extreme pressure and temperature conditions. 

Figure 10.31 shows all of the possible heat exchangers, mixers, and splitters, embedded within a single superstructure. A close examination of this superstructure identifies five altemative embedded substructures, including sequences in parallel, series, and combinations thereof, including the possibility of bypasses. 

One optimum requires a uniformly distributed entropy production rate in a heat exchanger, mixer, or separator. Consider the example of countercurrent and cocurrent heat exchangers shown in Figure 4.4. Temperature profiles show that the driving force AP or 1/AP is more uniformly distributed in the counter-current than in the cocurrent flow operation. This is the basic thermodynamic reason why a countercurrent is better than a cocurrent operation. The duty of the exchangers depends on the flow rate and Met and outlet temperatures T and T2 of cold streams. The duty is the amount of heat transferred from the hot fluid to cold... 

Conventional process equipment, such as heat exchangers, mixers, etc., vork in the turbulent flo v regime, where there is very good mixing by the turbulent eddies present in the flow. 

For each of these intensification challenges, the objective to be reached (volume reduction, reduced size/capadty ratio, etc.), and also the constraints (fixed productivity, fixed performance, quality specifications, etc.) can be identified and quantified with respect to technical and economic data. Unfortunately, the means to tackle these issues are much more complex to define since they can be of very different natures operating conditions (temperature, pressure, concentrations, etc.), physical or chemical parameters (solvents, catalysts, etc.), equipment (heat exchangers, mixers, columns, etc.), process parameters (reflux ratio, feed strategy of semi-batch reactors, separate unit operations or multi-functional reactors, separator types, etc.). In... 

The production of methylamines from methanol and ammonia is economically affected by the ratio of the demands of the three products (monomethylamine, dimethylamine, and trimethylamine). The recycle of trimethylamine will reduce the production of dimethylamine and trimethylamine relative to the production of monomethylamine. Similarly, the dilution of the reaction mixture with water will result in a relative increase in the production of monomethylamine. A mixer-heat exchanger-mixer portion of a methylamine plant is a proposed capital investment which would allow the relative production of the methylamines to be varied to meet changes in demand. 

Washing light hydrocarbons with water is a common refinery practice. It finds application on the feed to catalytic polymerization plants. It is used to remove any entrained caustic from the mercaptan removal facilities as well as any other impurities such as amines which tend to poison the polymerization catalyst. Another use for water wash is in alkylation plants to remove salts from streams, where heating would tend to deposit them out and plug up heat exchanger surfaces. Water washing can be carried out in a mixer- settler, or in a tower if more intimate contacting is necessary. 

Compact heat exchangers MicroChannel heat exchangers Rotor/stator mixers Rotating packed-bed Centrifugal adsorber... 

Table 1.2 Key data for production of polymers in the compact reactor/mixer/heat exchanger, termed micro reactor, by cationic polymerization yielding propylene, piperylene, butylenes, etc. [50].

As an example, a compact high-throughput turbulent flow reactor/mixer/heat exchanger was used for various applications, including polymer and rubber manufacture [50]. Further applications refer to emulsification and intensified heat exchange. 

The whole set-up for partial oxidation comprises a micro mixer for safe handling of explosive mixtures downstream (flame-arrestor effect), a micro heat exchanger for pre-heating reactant gases, the pressure vessel with the monolith reactor, a double-pipe heat exchanger for product gas cooling and a pneumatic pressure control valve to allow operation at elevated pressure [3]. 

D Microfab Micro Mixer-Micro Heat Exchangers... 

A chip-type micro reactor array comprises parallel mixer units composed of inverse mixing tees, each followed by a micro channel that it is surrounded by heat exchange micro channels (so called channel-by-channel approach similar to the tube-in-tube concept). Such an integrated device was developed as a stack of microstructured plates made of a special glass, termed Foturan (Figure 4.26). The integrated device was attached to PTFE tubes of various lengths. 

Reactor 28 [R28] Multi-channel Integrated Mixer-Heat Exchanger... 

Reactor type Multi-channel integrated mixer-heat exchanger Hydraulic diameter of cooling channel 900 pm... 

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