Regenerator system, reactor-heat

This reactor-heat regenerator system offers several important benefits. Temperature profiles inherently favor approach to chemical equilibrium and maximum use of the gaseous reducing agent over a wide range of operating rates. Yet, with the considerable heat capacity of the... 

Snamprogetti s dehydrogenation process consists of a fluidized-bed reactor and regeneration system. Here too, the coke buildup is very low and the regeneration loop is actually a means of supplying heat to the reactor. 

A fluidi2ed-bed catalytic reactor system developed by C. E. Lummus (323) offers several advantages over fixed-bed systems ia temperature control, heat and mass transfer, and continuity of operation. Higher catalyst activity levels and higher ethylene yields (99% compared to 94—96% with fixed-bed systems) are accompHshed by continuous circulation of catalyst between reactor and regenerator for carbon bum-off and continuous replacement of catalyst through attrition. 

In this section we develop a dynamic model from the same basis and assumptions as the steady-state model developed earlier. The model will include the necessarily unsteady-state dynamic terms, giving a set of initial value differential equations that describe the dynamic behavior of the system. Both the heat and coke capacitances are taken into consideration, while the vapor phase capacitances in both the dense and bubble phase are assumed negligible and therefore the corresponding mass-balance equations are assumed to be at pseudosteady state. This last assumption will be relaxed in the next subsection where the chemisorption capacities of gas oil and gasoline on the surface of the catalyst will be accounted for, albeit in a simple manner. In addition, the heat and mass capacities of the bubble phases are assumed to be negligible and thus the bubble phases of both the reactor and regenerator are assumed to be in a pseudosteady state. Based on these assumptions, the dynamics of the system are controlled by the thermal and coke dynamics in the dense phases of the reactor and of the regenerator. 

The preheated process and natural gas mixture enters the catalytic reduction system through a four-way flow reversing valve (9) and is further preheated as it flows upward through a packed-bed heat regenerator (10) before entering the reduction reactor (11). 

BRS—boron recycle s) em BTRS—boron thermal regeneration s) em CCW—component coolir water HX—heat exchanger RCS—reactor coolant system RHRS—residual heat removal system RMW—reactor makeup water RWST—refuelii water storj e tank WPS (L)—waste processii system (liquid)... 

Several competing fluidized-bed processes UNIPOL and BP processes compete Partial oxidation of butane competes with fixed-bed process Supplanted by fixed-bed process Highly exothermic, well suited to fluid bed Reactor/regenerator system Raises octane content while reducing benzene Converts olefins to C5+ hydrocarbons Ammoxidation of m-xylene Means of low-temperature oxidation with favorable heat transfer So far unable to displace fixed-bed in-furnace process... 

Heat regenerators are encountered in a number of large-scale industrial processes, such as open-hearth furnaces, liquefaction of a vapor, and the separation of its components in the liquid state. A hot gas, possibly leaving a reactor, is passed through a checkwork of bricks, or even a bed of stones, so that the heat is removed from the gas and stored in the solid. Then, a cold gas is passed through this bed, normally in the opposite direction, so that the gas is preheated before it enters the reactor. Derive a dynamic model for the system. Carefully define your terms and list your assumptions. 

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