Pound-mass

Double-Absorption Plants. In the United States, newer sulfuric acid plants ate requited to limit SO2 stack emissions to 2 kg of SO2 per metric ton of 100% acid produced (4 Ib /short ton Ib = pounds mass). This is equivalent to a sulfur dioxide conversion efficiency of 99.7%. Acid plants used as pollution control devices, for example those associated with smelters, have different regulations. This high conversion efficiency is not economically achievable by single absorption plants using available catalysts, but it can be attained in double absorption plants when the catalyst is not seriously degraded. 

Ibm avoirdupois) pound-mass/foot kilogram/meter (kg/m ) 1.66018463 X 10 ... 

By mathematical manipulation, numerous additional relationships can be derived from those given in Table 2-19. Of particular significance are expressions that relate enthalpy H and internal energy U to the measurable variables, P, V, and T. Thus, choosing the basis as one pound mass,... 

British thermal unit per pound-mass 2300 joules per kilogram... 

The English system of units is complicated compared to the metric system. In the English system, the units of mass are pounds-mass (Ibm) and the units of weight are pounds-force (Ibf). By definition, a weight (i.e., force) of one Ibf equals the force produced by one Ibm under the acceleration of gravity. Therefore, the constant, g, which has the same numerical value as g (32.17) and units of Ibm-ft/lbf-sec, is used in the definition of weight ... 

Misunderstanding often arises from the fact that the pound which is the unit of mass in the fps system has the same name as the unit of force in the engineering system. To avoid confusion the pound mass should be written as lb or even lbm and the unit of force always as lbf. 

Non-coherent system employing pound mass and pound force simultaneously... 

Two units which have never been popular in the last two systems of units (Sections 1.2.3 and 1.2.4) are the poundal (for force) and the slug (for mass). As a result, many writers, particularly in America, use both the pound mass and pound force as basic units in the same equation because they are the units in common use. This is an essentially incoherent system and requires great care in its use. In this system a proportionality factor between force and mass is defined as gc given by ... 

G is the superficial mass velocity in pounds mass per hour per square foot... 

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