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Reactor temperature control

The batch process is similar to the semibatch process except that most or all of the ingredients are added at the beginning of the reaction. Heat generation during a pure batch process makes reactor temperature control difficult, especially for high soHds latices. Seed, usually at 5—10% soHds, is routinely made via a batch process to produce a uniform particle-size distribution. Most kinetic studies and models are based on batch processes (69). [Pg.27]

FIG. 8-53 The reactor temperature controller sets coolant outlet temperature in cascade, with primary integral feedback taken from the secondary temperature measurement. [Pg.749]

Failure of the reactor temperature controller and reactor-stripper level controller... [Pg.254]

Calibrate the reactor temperature controller. Conduct a pressure survey around the feed nozzle piping to verify its mechanical integrity. [Pg.270]

The chapter by Haynes et al. describes the pilot work using Raney nickel catalysts with gas recycle for reactor temperature control. Gas recycle provides dilution of the carbon oxides in the feed gas to the methanator, hence simulating methanation of dilute CO-containing gases which under adiabatic conditions gives a permissible temperature rise. This and the next two papers basically treat this approach, the hallmark of first-generation methanation processes. [Pg.8]

By maintaining the first-stage reactor just beyond the phase inversion point, the dispersed rubber phase is relatively rich in dissolved styrene. As polymerization subsequently proceeds in the LFR s, the dissolved styrene will react to form either a graft copolymer with the rubber or a homopolymer. The latter will remain within the rubber droplet as a separate occluded phase. Achieving the first-stage reactor conversion and temperature by recycling a portion of the hot second reactor effluent may permit simplification of the first reactor temperature control system. [Pg.106]

The pyrolysis of the plastics was carried out in a semi-batch reactor which was made of cylindrical stainless steel tube with 80mm in internal diameter and 135mm in height. A schematic diagram of the experimental apparatus is shown in Fig. 1, which includes the main reactor, temperature controller, agitator, condenser and analyzers. [Pg.429]

Two simple forms of a batch reactor temperature control are possible, in which the reactor is either heated by a controlled supply of steam to the heating jacket, or cooled by a controlled flow of coolant (Fig. 3.18) Other control schemes would be to regulate the reactor flow rate or feed concentration, in order to maintain a given reaction rate (see simulation example SEMIEX). [Pg.156]

Proportional band settings of the reactor temperature controller, circulating jacket water temperature controller, and cooling water flow controller arc 20, 67, and 200, respectively. [Pg.244]

Figure S.2b shows another common system where cascade control is used. The reactor temperature controller is the primary controller the jacket temperature controller is the secondary controller. The reactor temperature control is isolated by the cascade system from disturbances in cooling-water inlet temperature and supply pressure. Figure S.2b shows another common system where cascade control is used. The reactor temperature controller is the primary controller the jacket temperature controller is the secondary controller. The reactor temperature control is isolated by the cascade system from disturbances in cooling-water inlet temperature and supply pressure.
Note that in the floating-pressure application, there was only one manipulated variable (cooling-water flow) and one primary controlled variable (valve position). In the reactor temperature-control application, there are two manipulated variables and two controlled variables (temperature and refrigerant valve position). [Pg.265]

Reactor temperature is controlled through a cascade system. Circulating water temperature is controlled by makeup cooling water. The setpoint of this temperature controller is set by the reactor temperature controller. The circulation rate of process liquid through the cooler is flow-controlled. [Pg.296]

The reactor temperature controller (loop 2) is the primary controller, whereas the jacket temperature controller (loop 3) is the secondary controller. The advantage of the cascade control is that the reactor temperature control quickly reacts by the cascade system to disturbances in cooling fluid inlet conditions. The d3mamics of the transfer function G32 is faster than that of G 22-In the CSTR cascade control there are two control loops using two different measurements temperatures T and Tj, but only one manipulated variable Fj. The transfer function of the primary controller is the following ... [Pg.21]

In addition to the high-pressure assembly, the modified system incorporates a new real-time data collection system coupled with a PC based computer. Experimental parameters, such as the valve firing sequence and the reactor temperature-control program, can be set from the computer. Reactants are introduced through two high-spe pulse valves or two continuous feed valves that are fed by mass flow controllers. In high-speed transient response experiments, the QMS is set at a particular mass value and the intensity variation as a function of time is obtained. In steady-flow experiments. [Pg.184]

The polytropic mode this is a combination of different types of control. As an example, the polytropic mode can be used to reduce the initial heat release rate by starting the feed and the reaction, at a lower temperature. The heat of reaction can then be used to heat up the reactor to the desired temperature. During the heating period, different strategies of temperature control can be applied adiabatic heating until a certain temperature level is reached, constant cooling medium temperature (isoperibolic control), or ramped to the desired reaction temperature in the reactor temperature controlled mode. Almost after the... [Pg.166]

An often-used method for the limitation of the heat release rate is an interlock of the feed with the temperature of the reaction mass. This method consists of halting the feed when the temperature reaches a predefined limit. This feed control strategy keeps the reactor temperature under control even in the case of poor dynamic behavior of the reactor temperature control system, should the heat exchange coefficient be lowered (e.g. fouling crusts) or feed rate too high. [Pg.169]

To implement the GMC, an energy balance around the reactor is required it gives the relation between the reactor temperature (controlled variable) and the jacket temperature (manipulated variable). Based on the assumption that the amount of the heat accumulated in the walls of the reactor... [Pg.107]

In the following, the model-based controller-observer adaptive scheme in [15] is presented. Namely, an observer is designed to estimate the effect of the heat released by the reaction on the reactor temperature dynamics then, this estimate is used by a cascade temperature control scheme, based on the closure of two temperature feedback loops, where the output of the reactor temperature controller becomes the setpoint of the cooling jacket temperature controller. Model-free variants of this control scheme are developed as well. The convergence of the overall controller-observer scheme, in terms of observer estimation errors and controller tracking errors, is proven via a Lyapunov-like argument. Noticeably, the scheme is developed for the general class of irreversible nonchain reactions presented in Sect. 2.5. [Pg.97]

Returning now to the issue of reactor temperature control, we can generally state that reactors with either substantially reversible or endothermic reactions seldom present temperature control problems. Endothermic reactions require that heat be supplied to generate products. Hence, they do not undergo the dangerous phenomenon of runaway because they are self-regulating, that is, an increase in temperature increases the reaction rate, which removes more heat and tends to decrease the temperature. [Pg.2]

This section has presented a brief review of some of the important kinetic concepts encountered in reactor analysis, modeling, and control. These concepts must be understood within the context of how they affect reactor temperature control and other aspects of reactor control. We recognize that many excellent reference books on chemical reaction engineering are available. These books cover the topic of kinetics and a host of other reactor design concepts in extensive depth. Our intention is not to attempt to provide anything like the scope of that material, so we assume some familiarity with it. A short list of excellent reference books includes... [Pg.14]

The key to reactor temperature control is to provide an excess of heat transfer area so that disturbances can be handled. [Pg.43]

A relay-feedback test on the reactor temperature controller is used to obtain the ultimate gain and frequency (K, = 64 and Pv = 10 min), using a 50 K temperature transmitter span and assuming the maximum cooling water flow is twice the steady-state value. The Tyreus-Luyben settings give oscillatory response, so the controller gain is reduced by factor of 2 (Kc = 10, t = 1320 s). [Pg.126]

There are two controllers. The proportional reactor level control has a gain of 5. The reactor temperature controller is tuned by running a relay-feedback test. The manipulated variable is the cooling water flowrate in the condenser. With a 50-K temperature transmitter span and the cooling water control valve half open at design conditions, the resulting tuning constants are Kc = 4.23 and = 25 min. [Pg.150]

REACTOR TEMPERATURE CONTROL USING FEED MANIPULATION... [Pg.154]

The reactor is the jacket-cooled CSTR with an irreversible, exothermic, liquid-phase reaction A —> B, which was considered in Section 3.1. In that section the flowrate of the cooling water Fj to the jacket was the manipulated variable for the reactor temperature controller (TR <— Fj control). In this section we explore the use of the flowrate of the fresh feed F() to control reactor temperature (TR <— F0 control). [Pg.154]

The flowrate of the cooling/heating medium is usually the manipulated variable that is changed by a reactor temperature controller, either directly or through a... [Pg.154]

Greg Shinskey1 presents a practical discussion of some of the advantages and problems of this control structure. The use of a valve position control (VPC) structure is recommended. A reactor temperature controller sets the coolant valve position. Then a VPC looks at the position of the coolant valve and adjusts the flowrate of the reactor feed to keep the coolant valve near its wide open position. [Pg.155]


See other pages where Reactor temperature control is mentioned: [Pg.193]    [Pg.95]    [Pg.111]    [Pg.56]    [Pg.7]    [Pg.189]    [Pg.215]    [Pg.107]    [Pg.24]    [Pg.27]    [Pg.31]    [Pg.136]    [Pg.137]    [Pg.141]    [Pg.154]    [Pg.155]    [Pg.163]   
See also in sourсe #XX -- [ Pg.174 ]

See also in sourсe #XX -- [ Pg.16 ]

See also in sourсe #XX -- [ Pg.174 ]

See also in sourсe #XX -- [ Pg.664 ]




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