Operation reactor design

When used to identify and evaluate significant risk contributors, as well as to assess the consequences of accident sequences, the PSA provides a comprehensive framework for making many types of decisions regarding reactor design, operation, and siting. These and other appi ications can be facilitated by the rational evaluation of the risks associated with a particular installation. 

The transformation of raw materials into products of greater value by means chemical reaction is a major industry, and a vast number of commercial prod is obtained by chemical synthesis. Sulfuric acid, ammonia, ethylene, propyl phosphoric acid, chlorine, nitric acid, urea, benzene, methanol, ethanol, ethylene glycol are examples of chemicals produced in the United States, billions of kilograms each year. These in turn are used in the large-scale manu ture of fibers, paints, detergents, plastics, rubber, fertilizers, insecticides, Clearly, the chemical engineer must be familiar with chemical-reactor design operation. 

The prinaples of latex reactor design, operation, and control will he illustrated by a consideration of the homopolymerization of styrene and vinyl acetate. Emulsion polymerization of vinyl acetate follows Case 1... 

Westerterp, K.R., Van Swaaij, W.P.M. and Beenackers, A.A.C.M. (1984), Chemical Reactor Design Operation , 2nd edition, John Wiley Sons, New York. 

This paper, which is divided into three sections, critically reviews the state-of-the-art of free-radical copolymerization kinetics, characterization, reactor design, operation and control from the view point of their possible implementation to industrial processes. 

Pollution Prevention Technologies Practices Batch operations Equipment parts cleaning Reactor design operation High-value waste Water usage Organic solvents pH control... 

Special thanks ie given to B. W. Herrman, Reactor Design Operation, for proof reewiing and commenting on the final copy. W. D. Hamilton, Plant Equipment Engineering Operation, is also recognized and acknowledged for... 

The simplicity of the reactor design, operation experience with pool-type research reactors and utilization in its construction of proven components (fuel rods, control rods and their driving mechanisms, heat exchangers, tanks, control systems) has allowed the designers to reduce the scope of the Research and Development Work. 

Nuclear Regulatory Commission, civilian agency following AEC to monitor nuclear materials and commercial nuclear power plants Nuclear Steam Supply System Office of Naval Reactors, Navy group responsible for reactor design, operation and safety Manhattan Project site for Large Scale Uranium Enrichment... 

Temperature control. Let us now consider temperature control of the reactor. In the first instance, adiabatic operation of the reactor should be considered, since this leads to the simplest and cheapest reactor design. If adiabatic operation produces an unacceptable rise in temperature for exothermic reactions or an unacceptable fall in temperature for endothermic reactions, this can be dealt with in a number of ways ... 

PVDE is manufactured using radical initiated batch polymerization processes in aqueous emulsion or suspension operating pressures may range from 1 to 20 MPa (10—200 atm) and temperatures from 10 to 130°C. Polymerization method, temperature, pressure, recipe ingredients, the manner in which they are added to the reactor, the reactor design, and post-reactor processing are variables that influence product characteristics and quaUty. 

Hydrothermal Synthesis Systems. Of the unit operations depicted in Figure 1, the pressurized sections from reactor inlet to pressure letdown ate key to hydrothermal process design. In consideration of scale-up of a hydrothermal process for high performance materials, several criteria must be considered. First, the mode of operation, which can be either continuous, semicontinuous, or batch, must be determined. Factors to consider ate the operating conditions, the manufacturing demand, the composition of the product mix (single or multiple products), the amount of waste that can be tolerated, and the materials of constmction requirements. Criteria for the selection of hydrothermal reactor design maybe summarized as... 

Wetox uses a single-reactor vessel that is baffled to simulate multiple stages. The design allows for higher destmction efficiency at lower power input and reduced temperature. Its commercial use has been limited to one faciHty in Canada for treatment of a complex industrial waste stream. Kenox Corp. (North York, Ontario, Canada) has developed a wet oxidation reactor design (28). The system operates at 4.1—4.7 MPa (600 to 680 psi) with air, using a static mixer to achieve good dispersion of Hquid and air bubbles. 

A commercial-scale lead Isasmelt reactor designed to treat 20 t/h concentrate and produce 60, 000 t/yr lead has been in operation at Mt. Isa since... 

Nuclear power has achieved an excellent safety record. Exceptions are the accidents at Three Mile Island in 1979 and at Chernobyl in 1986. In the United States, safety can be attributed in part to the strict regulation provided by the Nuclear Regulatory Commission, which reviews proposed reactor designs, processes appHcations forUcenses to constmct and operate plants, and provides surveillance of all safety-related activities of a utiUty. The utiUties seek continued improvement in capabiUty, use procedures extensively, and analy2e any plant incidents for their root causes. Similar programs intended to ensure reactor safety are in place in other countries. 

Account must be taken in design and operation of the requirements for the production and consumption of xenon-135 [14995-12-17, Xe, the daughter of iodine-135 [14834-68-5] Xenon-135 has an enormous thermal neutron cross section, around 2.7 x 10 cm (2.7 x 10 bams). Its reactivity effect is constant when a reactor is operating steadily, but if the reactor shuts down and the neutron flux is reduced, xenon-135 builds up and may prevent immediate restart of the reactor. 

Some reactors are designed specifically to withstand an explosion (14). The multitube fixed-bed reactors typically have ca 2.5-cm inside-diameter tubes, and heat from the highly exothermic oxidation reaction is removed by a circulating molten salt. This salt is a eutectic mixture of sodium and potassium nitrate and nitrite. Care must be taken in reactor design and operation because fires can result if the salt comes in contact with organic materials at the reactor operating temperature (15). Reactors containing over 20,000 tubes with a 45,000-ton annual production capacity have been constmcted. 

The same four operating steps are used with the complex batch reactor as with the simple batch reactor. The powerhil capabiUties of the complex batch reactor offset their relatively high capital cost. These reactors can operate at phenol to alkene mole ratios from 0.3 to 1 and up. This abiUty is achieved by designing for positive pressure operation, typically 200 to 2000 kPa (30 to 300 psig), and for the use of highly selective catalysts. Because these reactors can operate at low phenol to alkene mole ratios, they are ideal for production of di- and trialkylphenols. 

---