Transient temperature excursions in adiabatic packed bed reactors. The pseudohomogeneous model

Thesis/Dissertation · Sat Dec 31 23:00:00 EST 1977

OSTI ID:6900996

Mehta, P S

Transient temperature excursions occurring during an exothermic reaction in an adiabatic packed bed reactor as a result of a sudden drop in feed temperature can exceed significantly the steady-state adiabatic temperature rise. This could cause reduced catalytic activity by sintering, upset the reactor control, trigger undesired dormant reactions, and damage the reactor. A theoretical study of the dynamic behavior of a plug flow pseudo-homogeneous reactor by the method of characteristics showed that the maximum transient temperature increase depends mainly on the magnitude of the inlet disturbance, the activation energy of the reaction, and the adiabatic temperature rise. Its sensitivity to these parameters may be used to define parametric sensitivity under transient conditions. Reactors shorter than a certain critical length do not exhibit this behavior. For a zero-order reaction, increasing the duration of a ramp decrease in inlet temperature tended to dampen the phenomenon. The effect of isothermal intraparticle diffusional limitations on the transient response to a step disturbance was examined for a first-order reaction.

• OSTI ID: 6900996
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
320303 -- Energy Conservation
Consumption
& Utilization-- Industrial & Agricultural Processes-- Equipment & Processes
42 ENGINEERING
420200* -- Engineering-- Facilities
Equipment
& Techniques
ACTIVATION ENERGY
ADIABATIC PROCESSES
CHEMICAL REACTION KINETICS
CHEMICAL REACTORS
CRITICAL SIZE
ENERGY
FABRICATION
KINETICS
MATHEMATICAL MODELS
PACKED BED
REACTION KINETICS
SINTERING
SIZE
TEMPERATURE EFFECTS
TRANSIENTS