PID temperature controller

The catalytic reforming of CH4 by CO2 was carried out in a conventional fixed bed reactor system. Flow rates of reactants were controlled by mass flow controllers [Bronkhorst HI-TEC Co.]. The reactor, with an inner diameter of 0.007 m, was heated in an electric furnace. The reaction temperatoe was controlled by a PID temperature controller and was monitored by a separated thermocouple placed in the catalyst bed. The effluent gases were analyzed by an online GC [Hewlett Packard Co., HP-6890 Series II] equipped with a thermal conductivity detector (TCD) and carbosphere column (0.0032 m O.D. and 2.5 m length, 80/100 meshes), and identified by a GC/MS [Hewlett Packard Co., 5890/5971] equipped with an HP-1 capillary column (0.0002 m O.D. and 50 m length). 

Fig. 6.11. Performance of the digital PID temperature controller of the differential mixed-signal architecture in the tracking mode...

The converted temperature signal serves as input to the digital PID temperature controller so that the temperature control loop is closed (see Sect. 6.3.3 for a detailed description of the temperature control loop). 

FIG. 8-50 The response of a heat exchanger varies with flow in both gain and dynamics here the PID temperature controller was tuned for optimum response at 50 percent flow. 

Tj 0 is the jacket-inlet temperature, which is the manipulated variable in a PID temperature control loop, as will be discussed in Section 13.6.7. Integration of Eq. (13.70) gives the distribution of temperature along the jacket. In particular, the temperature at outlet is given by... 

TPSR for the catalysts deactivated by SO was made with a quadrupole mass spectrometer (MMPC-2(X)D, VG Quadrupoles). Deactivated catalysts were placed in a quartz U-shaped reactor of 1/4" O.D. The reactor was surrounded by a cylindrical electric furnace which was controlled by a PID temperature controller with a K-type thermocouple. After the reactor was fully purged with He (99.9999%) at 50°C, its temperature was ramped from 50 to 800°C at a heating rate of 10°C/min for identification by the mass spectrometer of compounds desorbing from the catalyst surface, e.g. H O, CO, COj, CH4, SOj and SO3. 

Various values for the control loop rate were used to evaluate the ability of the system to maintain real-time PID temperature control of the microreactor heaters. 

Furthermore, due to the absence of external heat sources, a metallic-shielded heating tape controlled by a PID temperature controller was wrapped all around the external surface of the reactor body, in order to carry out the thermal pretreatment of the membrane. 

Plastic Temperature. Correct temperature and uniformity are crucial for a consistent process. Monitoring of plastic temperature is difficult and rarely utilized in the industry. Control of temperature is done via thermocouples partially embedded into the barrel wall, usually three to four along the length of the barrel. The actual molten plastic is not monitored for temperature and >90% of the temperature values provided as data are barrel wall temperatures that can be off by 25°C (45°F). Temperature control is done via proportional-integral-derivative (PID) controllers or PID algorithms on computer controlled presses. Calibration of thermocouples is seldom done. PID temperature control of the nozzle tips is also important, yet 40% of the industry uses variacs. 

In order to minimize the temperature variation effects on the differential manometer pressure measurements, the whole apparatus is immersed in an oil bath maintained in constant temperature, by means of a PID temperature controller. The bath temperature variations are minimized by insulating the space over the bath and keeping its temperature constant to 0.1 °C by means of a PD temperature controller and an air circulation fan. In addition, the room temperature over the insulating cover is kept constant to 1 °C. 

An electronic PID temperature controller is at steady state with an output of 12 mA. The set point equals the nominal process temperature initially. At t = 0, the set point is increased at the rate of 0.5 mA/min (equivalent to a rate of 2°F/min). If the current settings are... 

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