-
[LEFT][FONT=Arial][COLOR=black][B]Reactors[/B][/COLOR][/FONT][/LEFT]
[SIZE=2][COLOR=black]A. The rate of reaction must be established in the laboratory and the residence time or space velocity [/COLOR][/SIZE]
[COLOR=black][SIZE=2]will eventually have to be determined in a pilot plant.[/SIZE][SIZE=2]B. Catalyst particle sizes: 0.10 mm for fluidized beds, 1 mm in slurry beds, and 2-5 mm in fixed beds.[/SIZE][/COLOR][LEFT][SIZE=2][COLOR=black]C. For homogeneous stirred tank reactions, the agitor power input should be about [/COLOR][/SIZE][/LEFT]
[COLOR=black][/COLOR]
[LEFT][SIZE=2][COLOR=black]0.5-1.5 hp/1000 gal (0.1-0.3 kW/m3), however, if heat is to be transferred, [/COLOR][/SIZE]
[SIZE=2][COLOR=black]the agitation should be about three times these amounts.[/COLOR][/SIZE]
[SIZE=2][COLOR=black]D. Ideal CSTR behavior is usually reached when the mean residence time is 5-10 times[/COLOR][/SIZE]
[SIZE=2][COLOR=black]the length needed to achieve homogeneity. Homogeneity is typically reached with[/COLOR][/SIZE]
[SIZE=2][COLOR=black]500-2000 revolutions of a properly designed stirrer.[/COLOR][/SIZE]
[SIZE=2][COLOR=black]E. Relatively slow reactions between liquids or slurries are usually conducted most[/COLOR][/SIZE]
[SIZE=2][COLOR=black]economically in a battery of 3-5 CSTR's in series.[/COLOR][/SIZE]
[SIZE=2][COLOR=black]F. Tubular flow reactors are typically used for high productions rates and when the [/COLOR][/SIZE]
[SIZE=2][COLOR=black]residence times are short. Tubular reactors are also a good choice when significant[/COLOR][/SIZE]
[SIZE=2][COLOR=black]heat transfer to or from the reactor is necessary.[/COLOR][/SIZE]
[SIZE=2][COLOR=black]G. For conversion under 95% of equilibrium, the reaction performance of a 5 stages[/COLOR][/SIZE]
[SIZE=2][COLOR=black]CSTR approaches that of a plug flow reactor.[/COLOR][/SIZE]
[SIZE=2][COLOR=black]H. Typically the chemical reaction rate will double for a 18 °F (10 °C) increase in [/COLOR][/SIZE]
[SIZE=2][COLOR=black]temperature.[/COLOR][/SIZE]
[SIZE=2][COLOR=black]I. The reaction rate in a heterogeneous reaction is often controlled more by the rate of[/COLOR][/SIZE]
[SIZE=2][COLOR=black]heat or mass transfer than by chemical kinetics.[/COLOR][/SIZE]
[SIZE=2][COLOR=black]J. Sometimes, catalysts usefulness is in improving selectivity rather than increasing[/COLOR][/SIZE]
[SIZE=2][COLOR=black]the rate of the reaction.[/COLOR][/SIZE][/LEFT]
-
[LEFT][FONT=Arial][B][COLOR=black]Refrigeration and Utilities[/COLOR][/B][/FONT]
[SIZE=2][COLOR=black]A. A ton of refrigeration equals the removal of 12,000 Btu/h (12,700 kJ/h) of heat[/COLOR][/SIZE]
[SIZE=2][COLOR=black]C. Cooling tower water is received from the tower between 80-90 °F (27-32 °C)[/COLOR][/SIZE]
[SIZE=2][COLOR=black]and should be returned between 115-125 °F (45-52 °C) depending on the size[/COLOR][/SIZE]
[SIZE=2][COLOR=black]of the tower. Seawater should be return no higher than 110 °F (43 °C)[/COLOR][/SIZE]
[SIZE=2][COLOR=black]D. Heat transfer fluids used: petroleum oils below 600 °F (315 °C), Dowtherms[/COLOR][/SIZE]
[SIZE=2][COLOR=black]or other synthetics below 750 °F (400 °C), molten salts below 1100 °F (600 °C)[/COLOR][/SIZE][/LEFT]
[SIZE=2][COLOR=black]E. Common compressed air pressures are: 45, 150, 300, and 450 psig[/COLOR][/SIZE][SIZE=2][COLOR=black]F. Instrument air is generally delivered around 45 psig with a dewpoint 30 °F below the coldest expected ambient temperature.[/COLOR][/SIZE]
[SIZE=3][COLOR=red][B]End article [/B][/COLOR][/SIZE]
[SIZE=3][COLOR=#ff0000][/COLOR][/SIZE]
[CENTER][SIZE=3][COLOR=red][B]Experienced-Based Rules of Chemical Engineering[/B][/COLOR][/SIZE][/CENTER]
[SIZE=3][COLOR=red][/COLOR][/SIZE]
[SIZE=3][COLOR=red][/COLOR][/SIZE]
[CENTER][SIZE=3][COLOR=red][B]By Eng. Chris Haslego[/B][/COLOR][/SIZE][/CENTER]
-
-
-
-
-
-
-
-
thanks you for sharing....
