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Various governmental agencies involved with environmental protection and with occupational safety and health have promulgated regulations limiting the allowable concentrations of gaseous pollutants in the ambient air or in emissions to the ambient air. Such regulations involve a number of different expressions of concentration. Some express the allowable concentrations as volume of a specific gaseous pollutant per million volumes of ambient air or, more simply as parts per million by volume (ppmv). Others express the allowable concentrations as mass of a specific gaseous pollutant per volume of ambient air or usually as milligrams per cubic meter (mg/m³). The equations for conversion between ppmv and mg/m³ depend on the temperature at which the conversion is wanted (usually about 20 to 25 °C). At an ambient air pressure of 1 atmosphere of 101.325 kiloPascal (kPa), the general conversion equation is: ppmv = (mg/m³) × (0.08205) × (T) / (M) and for the reverse conversion: (mg/m³) = (ppmv) × (M) (12.187) / (T) where: ppmv = air pollutant concentration, in parts per million by volume mg/m³ = milligrams of air pollutant per cubic meter of air T = ambient air temperature, in kelvins (K) = 273.15 + °C 0.08205 = Universal Gas Law constant, in [atm·L]/(mol·K) M = molecular weight of the air pollutant (dimensionless) Notes: -- Pollution regulations in the United States typically reference their air pollutant limits to an ambient temperature of 20 to 25 °C as noted above. In most other nations, the reference ambient temperature for pollutant limits may be 0 °C or other values. -- 1 percent by volume = 10,000 ppmv -- atm = absolute atmosperic pressure in atmospheres -- mol = gram mole -- L = liter

Would it help you to know that Frederick Seitz, past president of the National Academy of Science (USA), thinks that globing warming theory is based on flawed ideas? Would it also help you to know that Rcihard Lindzen, the Alfred Sloan Professor of Meteorology at the Massachussetts Institute of Technology (MIT), is one of the most outspoken skeptics of the global warming theory? If you need further confirmation that the global warming theory is flawed, read this article: A.B. Robinson, N.E. Robinson and Willie Soon, "Environmental Effects of Increased Atmospheric Carbon Dioxide", Journal of American Physicians and Surgeons (2007) 12, 78-90.

Various governmental agencies involved with environmental protection and with occupational safety and health have promulgated regulations limiting the allowable concentrations of gaseous pollutants in the ambient air or in emissions to the ambient air. Such regulations involve a number of different expressions of concentration. Some express the allowable concentrations as volume of a specific gaseous pollutant per million volumes of ambient air or, more simply as parts per million by volume (ppmv). Others express the allowable concentrations as mass of a specific gaseous pollutant per volume of ambient air or usually as milligrams per cubic meter (mg/m³). The equations for conversion between ppmv and mg/m³ depend on the temperature at which the conversion is wanted (usually about 20 to 25 °C). At an ambient air pressure of 1 atmosphere of 101.325 kiloPascal (kPa), the general conversion equation is: ppmv = (mg/m³) × (0.08205) × (T) / (M) and for the reverse conversion: (mg/m³) = (ppmv) × (M) (12.187) / (T) where: ppmv = air pollutant concentration, in parts per million by volume mg/m³ = milligrams of air pollutant per cubic meter of air T = ambient air temperature, in kelvins (K) = 273.15 + °C 0.08205 = Universal Gas Law constant, in [atm·L]/(mol·K) M = molecular weight of the air pollutant (dimensionless) Notes: -- Pollution regulations in the United States typically reference their air pollutant limits to an ambient temperature of 20 to 25 °C as noted above. In most other nations, the reference ambient temperature for pollutant limits may be 0 °C or other values. -- 1 percent by volume = 10,000 ppmv -- atm = absolute atmosperic pressure in atmospheres -- mol = gram mole -- L = liter

Calculating the viscosity of a blended liquid consisting of two or more liquids having different viscosities is a three step procedure. The first step involves calculation of the Viscosity Blending Index (VBI) of each component of the blend using the following equation (known as a Refutas equation): (1) VBI = 14.534 × ln[ln(v + 0.8)] + 10.975 where v is the viscosity in centistokes and ln is the natural logarithm (Loge). The second step involves using this blending equation: (2) VBIBlend = [wA × VBIA] + [wB × VBIB] + ... + [wX × VBIX] where w is the weight fraction (i.e., % ÷ 100) of each component of the blend. In using the above blending equation, it is necessary that all viscosities are determined at the same temperature, for example, 100 oC. The third and final step is to determine the viscosity of the blend by using the invert of equation (1): (3) v = ee(VBI - 10.975) ÷ 14.534 − 0.8 where VBI is the Viscosity Blending Index of the blend and e is the transcendental number 2.71828, also known as [[Euler's number]].

Calculating the viscosity of a blended liquid consisting of two or more liquids having different viscosities is a three step procedure. The first step involves calculation of the Viscosity Blending Index (VBI) of each component of the blend using the following equation (known as a Refutas equation): (1) VBI = 14.534 × ln[ln(v + 0.8)] + 10.975 where v is the viscosity in centistokes and ln is the natural logarithm (Loge). The second step involves using this blending equation: (2) VBIBlend = [wA × VBIA] + [wB × VBIB] + ... + [wX × VBIX] where w is the weight fraction (i.e., % ÷ 100) of each component of the blend. In using the above blending equation, it is necessary that all viscosities are determined at the same temperature, for example, 100 oC. The third and final step is to determine the viscosity of the blend by using the invert of equation (1): (3) v = ee(VBI - 10.975) ÷ 14.534 − 0.8 where VBI is the Viscosity Blending Index of the blend and e is the transcendental number 2.71828, also known as [[Euler's number]].

A vapor-liquid separator drum is a vertical vessel into which a liquid and vapor mixture (or a flashing liquid) is fed and wherein the liquid is separated by gravity, falls to the bottom of the vessel, and is withdrawn. The vapor travels upward at a design velocity which minimizes the entrainment of any liquid droplets in the vapor as it exits the top of the vessel. The size a vapor-liquid separator drum (or knock-out pot, or flash drum, or compressor suction drum) should be dictated by the anticipated flow rate of vapor and liquid from the drum. The following sizing methodology is based on the assumption that those flow rates are known. Use a vertical pressure vessel with a length-to-diameter ratio of about 3 to 4, and size the vessel to provide about 5 minutes of liquid inventory between the normal liquid level and the bottom of the vessel (with the normal liquid level being at about the vessel's half-full level). For the maximum design vapor velocity (which will set the drum's diameter), use the Souders-Brown equation: Vmax = (k) [ (dL - dV) / dV ]^0.5 where: Vmax = maximum design vapor velocity, ft/sec dL = liquid density, lb/ft3 dV = vapor density, lb/ft3 k = 0.35 (when the drum includes a de-entraining mesh pad) The drum should have a vapor outlet at the top, liquid outlet at the bottom, and feed inlet at somewhat above the half-full level. At the vapor outlet, provide a de-entraining mesh pad within the drum such that the vapor must pass through that mesh before it can leave the drum. Depending upon how much liquid flow you expect, the liquid outlet line should probably have a level control valve. As for the mechanical design of the drum (i.e., materials of construction, wall thickness, corrosion allowance, etc.), use the same methodology as for any pressure vessel.

Here are the governing relationships for the makeup flow rate, the evaporation and windage losses, the draw-off rate, and the concentration cycles in an evaporative cooling tower system: M = Make-up water in gal/min C = Circulating water in gal/min D = Draw-off water in gal/min E = Evaporated water in gal/min W = Windage loss of water in gal/min X = Concentration in ppmw (of any completely soluble salts … usually chlorides) XM = Concentration of chlorides in make-up water (M), in ppmw XC = Concentration of chlorides in circulating water ©, in ppmw Cycles = Cycles of concentration = XC / XM ppmw = parts per million by weight A water balance around the entire system is: M = E + D + W Since the evaporated water (E) has no salts, a chloride balance around the system is: M (XM) = D (XC) + W (XC) = XC (D + W) and, therefore: XC / XM = Cycles = M / (D + W) = M / (M – E) = 1 + {E / (D + W)} From a simplified heat balance around the cooling tower: (E) = © (ΔT) (cp) / HV where: HV = latent heat of vaporization of water = ca. 1,000 Btu/pound ΔT = temperature difference from tower top to tower bottom, in °F cp = specific heat of water = 1 Btu/pound/°F Windage losses (W), in the absence of manufacturer's data, may be assumed to be: W = 0.3 to 1.0 percent of C for a natural draft cooling tower W = 0.1 to 0.3 percent of C for an induced draft cooling tower W = about 0.01 percent of C if the cooling tower has windage drift eliminators Concentration cycles in petroleum refinery cooling towers usually range from 3 to 7. In some large power plants, the cooling tower concentration cycles may be much higher. (Note: Draw-off and blowdown are synonymous. Windage and drift are also synonymous.)

How to determine the mass flow rate of a gas through an orifice or leak at choked flow conditions is a question that is often raised by those unfamiliar with fluid flow mechanics. Here are the applicable equations:

Anyone interested in or involved with air pollution dispersion modeling is invited to visit the website at: ........ www.air-dispersion.com <== click here to learn about "Fundamentals of Stack Gas Dispersion" ... a very comprehensive reference book on dispersion modeling of continuous, buoyant pollution plumes. The website provides a brief description of the book, peer reviews published in technical journals, the book's complete table of contents, and other information. The website also provides access to information about the AERMOD, SLAB and DEGADIS dispersion models and other BREEZE software used by environmental professionals worldwide. Topics covered in the book include: classifying atmospheric stability; determining of buoyant pollution plume rise; Gaussian dispersion calculations and modeling; developing windspeed profiles; trapped pollution plumes; fumigated plumes; flare stack plumes; meteorological parameters, and much more. Copies of the book have been purchased in the U.S.A., Canada, Mexico, South America, Europe, Australia, Africa and Asia (in a total of 57 countries), and are available in over 130 libraries worldwide. Milton Beychok Newport Beach, CA 92660, USA Here is the front cover of the book:

Anyone interested in or involved with air pollution dispersion modeling is invited to visit the website at: ........ http://www.air-dispersion.com <== click here to learn about "Fundamentals of Stack Gas Dispersion" ... a very comprehensive reference book on dispersion modeling of continuous, buoyant pollution plumes. The website provides a brief description of the book, peer reviews published in technical journals, the book's complete table of contents, and other information. Topics covered in the book include: classifying atmospheric stability; determining of buoyant pollution plume rise; Gaussian dispersion calculations and modeling; developing windspeed profiles; trapped pollution plumes; fumigated plumes; flare stack plumes; meteorological parameters, and much more. Copies of the book have been purchased in the U.S.A., Canada, Mexico, South America, Europe, Australia, Africa and Asia (in a total of 56 countries), and are available in over 125 libraries worldwide. Milton Beychok Newport Beach, CA 92660, USA Here is the front cover of the book:

Richard Cates: A more correct expression of Bernoulli's Theorem is: P1/dg + V12/2g + Z1 = P2/dg + V22/2g + Z2 + Hf where: P1 and P2 = the static pressures at points 1 and 2 in the flow direction d = the fluid density g = gravitational acceleration P1/dg and P2/dg = the pressure heads at points 1 and 2 V12 and V22 = the fluid velocities at points 1 and 2 V12/2g and V22/2g = the velocity heads at points 1 and 2 Z1 and Z2 = the elevation heads at points 1 and 2 Hf = the frictional head loss between points 1 and 2 It is very important to note that: The above expression of Bernoulli's Theorem is only valid when P1 and P2 are in the SI metric pressure units of Newtons per square meter (N/m2) ... such as Pascals (Pa) since 1 Pa = 1 N/m2, or such as Bars since 1 Bar = 100,000 N/m2. When P1 and P2 are in the USA units of pounds per square foot (psf) then the pressure head terms become P1/d and P2/d. In other words, the gravitational acceleration (g) is not included in the pressure head terms ... however, it remains in the velocity head terms. The reason for the above differences in the pressure head terms between the SI metric expression and the USA expression is that the Newton (N) is a unit of force which includes the gravitational acceleration ... whereas the pounds per square foot (psf) is not a unit of force and does not include the gravitational acceleration. I hope this helps you, Milton Beychok (Visit me at http://www.air-dispersion.com)

Operator: A metric ton (i.e., a tonne) of refrigeration is equivalent to the amount of heat required to melt a metric ton (i.e., 1000 kg) of ice in 24 hours. Thus, a tonne of refrigeration is equivalent to removing 334,000/24 = 13,917 kJ/hour ... not 334,000 kJ/hour. Milt Beychok (Visit me at http://www.air-dispersion.com)

Yes, the vacuum pump must be kept running during the distillation. Any internal or external condenser is probably used to provide reflux to aid the distillation. Milt Beychok (Visit me at http://www.air-dispersion.com)

For those of you who may occasionally perform or review air pollution dispersion modeling studies:

I have used Netscape as my email client for 5 years now ... and I think it is far , far better that Outlook Express. Milt Beychok

Anyone interested in or involved with air pollution dispersion modeling is invited to visit the website at: ........ www.air-dispersion.com <== click here to learn about "Fundamentals of Stack Gas Dispersion" ... a very comprehensive reference book on dispersion modeling of continuous, buoyant pollution plumes. The website provides a brief description of the book, peer reviews published in technical journals, the book's complete table of contents, and other information. Topics covered in the book include: classifying atmospheric stability; determining of buoyant pollution plume rise; Gaussian dispersion calculations and modeling; developing windspeed profiles; trapped pollution plumes; fumigated plumes; flare stack plumes; meteorological parameters, and much more. Copies of the book have been purchased in the U.S.A., Canada, Mexico, South America, Europe, Australia, Africa and Asia (in a total of 56 countries), and are available in over 125 libraries worldwide. Milton Beychok Newport Beach, CA 92660, USA Here is the front cover of the book: