Cooling or heating systems

Establish process control systems capable of maintaining conditions within safe limits (may include emergency cooling or heating systems). 

Thermosets unlike thermoplastics require heating in the mould and not cooling. The demoulding temperature is therefore the temperature the mould is set at for crosslinking. More details on controlling the cooling or heating systems can be found in Chapter 8. 

A versatile Laser-SNMS instrument consists of a versatile microfocus ion gun, a sputtering ion gun, a liquid metal ion gun, a pulsed flood electron gun, a resonant laser system consisting of a pulsed Nd YAG laser pumping two dye lasers, a non-resonant laser system consisting of a high-power excimer or Nd YAG laser, a computer-controlled high-resolution sample manipulator on which samples can be cooled or heated, a video and electron imaging system, a vacuum lock for sample introduction, and a TOF mass spectrometer. 

Fig. 6 shows both the actual cycle (shown in dashed lines) and the idealised cycle, which consists of two isosteres and two isobars. Heat flows in J/kg adsorbent q) are shown as shaded arrows. For most purposes, analysis of the ideal cycle gives an adequate estimate of the COP and cooling or heating per kg of adsorbent. An accurate calculation of the path of the actual cycle needs information on the dead volume of the whole system and of the heat transfer characteristics of the condenser and evaporator. General trends are more apparent from an analysis of the idealised cycle. 

In predicting the time required to cool or heat a process fluid in a full-scale batch reactor for unsteady state heat transfer, consider a batch reactor (Figure 13-2) with an external half-pipe coil jacket and non-isothermal cooling medium (see Chapter 7). From the derivation, the time 6 to heat the batch system is ... 

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. 

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