Heating-cooling system

Limit temperature of heating medium Use split heating/cooling system to eliminate heat transfer to unwetted surface Heat with sparged steam/tempered water Avoid splashing of material onto unwetted heating surface... 

The reactor to be used is a 4m3 stainless steel stirred tank following DIN-Standards [20]. It is equipped with a indirect heating cooling system using a monofluid (water-diethylene glycole mixture) circulating in a heat exchanger... 

The specific heat of reaction is 125 kj mol"1 (aromatic compound) and the specific heat capacity of the reaction mixture is 2.8kjkg 1 K"1. What maximum temperature (MTSR) could the reaction mass reach if the heating cooling system fails to stabilize at 125 °C ... 

The analysis of the incident showed that this reactor was equipped with an indirect heating-cooling system with oil circulation and computerized temperature control. In this plant, to obtain a nervous temperature control, the control algorithm of the cascade controller (see Section 9.2.4.3) was adjusted to have an on-off behaviour, by calculating the set temperature of the jacket proportional to the squared difference between the actual and set values of the reaction medium temperature as... 

In order to control the reaction course and so avoid a runaway incident, it is essential to understand how heating-cooling systems of reactors work and what their performance is. These topics are reviewed in this chapter, where different heating and cooling systems are reviewed from the particular implications on process safety. In the first section, the different heating and cooling techniques... 

Table 9.2 Valve switching for a single circuit heating cooling system.

Figure 9.5 Heating cooling system with single circuit. The valves are as flows (1) steam inlet, (2) cooling water outlet, (3) purge, (4) cold water inlet, (5) condensate outlet.

Figu re 9.6 Single-circuit heating cooling system with steam, water, and brine. 

Figure 9.8 Heating cooling system with secondary circulation loop.

To illustrate some of the design and control issues, a vessel size (DR = 2 m, VR = 12.57 m3, jacket heat transfer area Aj = 25.13 m2) and a maximum reactor temperature (7j) ax = 340 K) are selected. The vessel is initially heated with a hot fluid until the reaction begins to generate heat. Then a cold fluid is used. A split-range-heating/ cooling system is used that adds hot or cold water to a circulating-water system, which is assumed to be perfectly mixed at temperature Tj. The setpoint of a reactor temperature controller is ramped up from 300 K to the maximum temperature over some time period. 

Figure 13.7 Configuration of the heating/cooling system for VCM polymerization.

LeLann et al. [6] discuss tendency modeling (using approximate stoichiometric and kinetic models for a reaction) and the use of model predictive control (linear and nonlinear) in batch reactor operation. Studies of a hybrid heating-cooling system on a 16-L pilot plant are presented. 

In this option, a higher concentration, 60 gm/liter at 60 C, is achieved by a heat/cool system, as shown in Fig. 11-2. The short contact time for heating to achieve dissolution and cooling to a stable temperature, 1 minute total, is consistent with chemical stability. 

Filter (air) - A device that removes contaminants, by mechanical filtration, from the fresh air stream before the air enters the living space. Filters can be installed as part of a heating/cooling system through which air flows for the purpose of removing particulates before or after the air enters the mechanical components. 

Supply Duct - The duct(s) of a forced air heating/cooling system through which heated or cooled air is supplied to rooms by the action of the fan of the central heating or cooling unit. 

To provide temperature control, the barrel is divided into zones. Each of these zones is fitted with its own external heating/cooling system. The smallest machine will have three zones and larger machines may have twelve. A temperature sensor and associated equipment, usually a microprocessor-based controller for each of the zones developing a temperature profile to provide the best melt. Target for these controllers is to measiue the melt temperatures that are important rather than the cylinder temperatures. 

What types of gating and ruimer systems exist What types of heating/cooling systems are available ... 

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