Heat furnace reactors

If the system consists of a series of adiabatic reactors, there are two basic configurations. The first has heat exchangers or furnaces between each of the reactors to cool or heat the reactor effluent before it enters the next reactor. The second configuration uses cold shot cooling. Some of the cold reactor feed is bypassed around the upstream reac-tor(s) and mixed with the hot effluent from the reactor to lower the inlet temperature to the downstream catalyst bed. 

However, a small-diameter tube gives more pressure drop for a given flowrate through each tube and a given tube length. Of course, a larger number of parallel tubes that are shorter can be used to keep pressure drop at a reasonable level, but this increases the shell diameter of the reactor, which increases the cost. Mechanical problems also limit the minimum tube diameter. Typical tube diameter in cooled tubular reactors is 0.03 m. Typical tube diameter in a furnace-fired heated tubular reactor is 0.15 m. 

Reyes, F. and Luyben, W. L. (2000a). Steady-state and dynamic effects of design alternatives in heat-exchanger/furnace/reactor processes. Ind. Eng. Chem. Res., 39, 3335-3346. 

Conventional technology, which has been employed for over 25 years, uses three or four fixed bed reactors in series, these operating under adiabatic conditions. They are preceeded by heating furnaces that compensate for the overall endothermicity of the reaction. Catalyst performance was investigated separately in a pilot plant under isothermal conditions, employing ca. 300-400 g of catalyst. 

Step 3. The exothermic heat of reaction must be removed, and the reactor feed must be heated to a high enough temperature to initiate the reaction. Since the heat of reaction is not large and complete one-pass conversion is not achieved, the reactor exit temperature is only 32°F higher than the reactor inlet temperature. Since heat transfer coefficients in gas-to-gas systems are typically quite low, this small temperature differential would require a very large heat exchanger if only the reactor effluent is used to heat the reactor feed and no furnace... 

This reaction was studied [10-13] in a heated furnace (both horizontal and vertical) and a magnetically rotated dc plasma reactor. In the magnetically rotated dc plasma reactor Mahawili and Weinberg [10] found the reassociation of Cl radicals affects the global reaction rate at low oxygen concentration. Under these conditions, the reaction was zero order with respect to TiCl4 and oxygen... 

It has been suggested that the design and operational practices for cracking furnace reactors can be put to use for heat supply to inorganic membrane reactors [Tsotsis et al., 19931. Having sufficient electrical conductivity at typical reaction temperatures for dehydrogenation reactions, ceramic membranes allow the use of electric current through... 

Heat balance of the bench-scale reactor is maintained in one of two ways. If the feed material is of relatively high heating value (greater than 14.0 MJ kg l, 6000 Btu/lb), a small air cooler at the bottom of the furnace is used to maintain the vessel at the operating temperature. If the waste material is low in heating value, the melt temperature is maintained by an electrically heated furnace, or by adding auxiliary fuel to the waste,... 

Temperature uniformity within the reactor is one of the key parameters to be precisely controlled for CVD processes. For thin film deposition on the surface of silicon wafers, multizone (up to five zones) resistively heated furnaces are designed to enable a uniform temperature field for the deposition of the thin film, as shown in Figure 3.21. Several kinds of thermocouples (Types B, K, R and S) are available for CVD systems to measure temperatures. The features of these thermocouples are hsted in Table 3.5. Because the CVD processing atmosphere... 

A 24-in. long, 2.75-in. diameter Kanthal furnace heated the reactor. All thermocouples were Chromel-Alumel. Multiple-point recorders were used. Gases were analyzed using Fisher partitioners to obtain N2, C02, CO, and hydrogen by difference. Mass spectrometric and other gas chromatographic equipment were utilized when necessary. 

The reactor is a thin-walled stainless steel vessel 1-in. i.d. X 6-in. long and is contained along with its heating furnace and insulation by a 1-liter high pressure autoclave (not shown). The reactor internal pressure is balanced by adding C02 from an external source to the autoclave. 

The flowsheet (Figure 17.9) contains a feed-effluent heat exchanger (FEHE), furnace, reactor, quench unit and steam generator. The following controllers can be considered ... 

Description The technology encompasses two main processing areas reactor section and product distillation section. In this process, Cg aromatics feed stream is first mixed with hydrogen. The mixed stream is then heated against reactor effluent and sent through a process furnace. The heated mixture is fed into the DX reaction unit, where EB is de-alkylated at very high conversion,k and xylenes are isomerized to equilibrium. 

For resistance-heated furnaces on a modest scale (e.g., a 1-5 1 reactor), a simple, trapped, diffusion-pumped apparatus constructed of stainless steel or glass capable of achieving <10 mbar is sufficient. 

The energy source provides energy or heat required for precursors to react. For a hot-walled reactor system, heated furnaces are used for indirect heating of the substrate. The drawback of this mechanism is that the wall of the reactor chamber is also coated which lowers deposition efficiency... 

Crystalline boron carbide nanopartides have been obtained by Chang et al. [ 141 ] by heating a mixture of amorphous carbon and amorphous boron at 1550 °C in a conventional high-temperature furnace reactor. The average size of B4C partides was 200 nm. 

A feasibility scoping study enabled by process simulation is the preliminary evaluation of improvement ideas in the context of overall process with the main objectives to perform cost and benefit analysis and determine if major equipment can accommodate the improvement ideas. The major equipment includes furnaces, reactors, main fractionators and separators, compressors, special pumps, and major heat exchangers. Usually, the scoping study is not concerned with relative ancillary equipment such as receivers, drums, heat exchangers, pumps, piping, instruments, relief valves, and so on. 

The initiation temperature is achieved as rapidly as possible by lowering the reactor into a gas-heated furnace which is already at a temperature of about 1000°C. This minimizes pre-reaction , i.e. a series of slow local reactions which would dissipate some of the available heat before the point of rapid initiation. Thus the maximum temperature peak is achieved for the maximum duration, so allowing good settling and agglomeration of the uranium metal. 

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