Control energy conservation

Advances in fundamental knowledge of adsorption equihbrium and mass transfer will enable further optimization of the performance of existing adsorbent types. Continuing discoveries of new molecular sieve materials will also provide adsorbents with new combinations of useflil properties. New adsorbents and adsorption processes will be developed to provide needed improvements in pollution control, energy conservation, and the separation of high value chemicals. New process cycles and new hybrid processes linking adsorption with other unit operations will continue to be developed. 

In addition to energy conservation, the variable speed drives offer better control because of a faster response, ie, reduced dead band. They are also sometimes chosen for safety reasons because of elimination of the control station and accompanying valving. The capital saved by use of a smaller motor and elimination of the control valve partially compensates for the cost of the drive. 

A very important feature of solid-state technology is energy conservation in the process of speed control. The slip losses that appear in the rotor circuit are now totally eliminated. With the application of this technology, we can change the characteristics of the motor so that the voltage and frequency are set at values just sufficient to meet the speed and power requirements of the load. The power drawn from the mains is completely utilized in doing useful work rather than appearing as stator losses, rotor slip losses or external resistance losses of the rotor circuit. 

Variable voltage (fixed frequency) static control Figure 6.40 Energy conservation through static control... 

Control of the compressor is achieved by engaging the required number of cylinders. In. say. a 16-cylinder compressor if we engage only four cylinders, the compressor will run at 25 7r capacity, and if w c engage eight cylinders, the compressor will run at. 5()C< capacity. Electrically operated solenoid valves are provided for capacity control. Energy can be conserved by using static controls, as discussed in Section 6.15. 

This part-also deals w ith static controls and drives, soft starting and process control through solid-state technology (phasor and field-oriented controls) using IGBTs as well as energy conservation,... 

Centrifugal (radial inflow) turboexpanders are well adapted to such energy conservation schemes and, with recent developments that have increased their reliability, are suitable for unattended service on a 24-hour, 7-day week operational basis. Some of the recent developments include better shaft seals, thrust bearing monitoring, and superior control devices. 

Shinskey, F. G., Energy-Conserving Control Systems for Distillation Units, Chemical Engineering Progress, May 1976. 

Sittig, Marshall. 1979. Fertilizer Industry Processes, Pollution Control and Energy Conservation. Park Ridge, N.J. Noyes Data Corporation. 

Zilko, P. S., Apply Demand Controls for Energy Conservation, Specifying Engr., p. 74, Eeb. (1981). 

Plant safety, energy conservation, pollution control and environmental compliance... 

In order to achieve economy in the use of water it will have to be re-cooled. This is achieved by transferring heat to the ambient air by means of cooling ponds, towers, tanks or mechanical coolers. Temperature regulators may assist control and conserve energy. 

There are comparable incentives to develop new process-related materials that are more selective as catalysts, extractants, or separation membranes and more effective in controlling flow in porous media. In addition, the development of materials that are less energy intensive in terms of production and use is a goal equivalent to other means of energy conservation. 

Column pressure is normally controlled at a constant value. The use of variable pressure control to conserve energy has been discussed by Shinskey (1976). 

SHINSKEY, F. G. (1976) Chem. Eng. Prog. 72 (May) 73. Energy-conserving control systems for distillation units. SHINSKEY, F. G. (1984) Distillation Control, 2nd edn (McGraw-Hill). 

The energy conservation is written for a control volume surrounding a moving premixed flame at velocity Sa into a fuel-air mixture at rest. The equation is given below ... 

Figure 8.9 Control volume energy conservation for a thermally thick solid with flame spread steady velocity, Up...

---