Volume percent

The non-hydrocarbon components of crude oil may be small in volume percent, typically less than 1 %, but their influence on the product quality and the processing requirements can be considerable. It is therefore important to identify the presence of these components as early as possible, and certainly before the field development planning stage, to enable the appropriate choice of processing facilities and materials of construction to be made. 

Weight percent (% w/w), volume percent (% v/v) and weight-to-volume percent... 

The units of concentration most frequently encountered in analytical chemistry are molarity, weight percent, volume percent, weight-to-volume percent, parts per million, and parts per billion. By recognizing the general definition of concentration given in equation 2.1, it is easy to convert between concentration units. 

A stock solution is prepared by weighing out an appropriate portion of a pure solid or by measuring out an appropriate volume of a pure liquid and diluting to a known volume. Exactly how this is done depends on the required concentration units. For example, to prepare a solution with a desired molarity you would weigh out an appropriate mass of the reagent, dissolve it in a portion of solvent, and bring to the desired volume. To prepare a solution where the solute s concentration is given as a volume percent, you would measure out an appropriate volume of solute and add sufficient solvent to obtain the desired total volume. 

Usually, free-radical initiators such as azo compounds or peroxides are used to initiate the polymerization of acrylic monomers. Photochemical (72—74) and radiation-initiated (75) polymerizations are also well known. At a constant temperature, the initial rate of the bulk or solution radical polymerization of acrylic monomers is first order with respect to monomer concentration and one-half order with respect to the initiator concentration. Rate data for polymerization of several common acrylic monomers initiated with 2,2 -azobisisobutyronittile (AIBN) [78-67-1] have been determined and are shown in Table 6. The table also includes heats of polymerization and volume percent shrinkage data. 

The specifications for drilling fluid hematite have been set by the API and are Hsted in Table 2 (24). Hematite is used most frequently in high density oil-based muds to minimise the total volume percent soflds (26). The abrasivity of hematite limits its utiUty in water-based muds. 

The chemical and mechanical dispersion of the drilled soHds tends to increase the percentage of smaH-sized soHds in a mud as drilling progresses. The incorporation of a limited amount of drilled soHds (several volume percent) is an economical way of increasing the density of low density muds, but it also reduces penetration rates hence, drilled soHds are usually kept to a minimum. The common clay and formation soHds encountered in normal drilling operations are as foUows ... 

The hot mixes are designed by using a standard laboratory compaction procedure to develop a composition reflecting estabUshed criteria for volume percent air voids, total volume percent voids between aggregate particles, flow and stabdity, or compressive strength. Tests such as the Marshall, Unconfined Compression, Hubbard-Field, Triaxial Procedure, or the Hveem stabdometer method are used (109). 

Two sets of fi and g are given in the article for each second-order group to cover both upper (u) and lower (/) hmits (z) in volume percent units. A study of this method for about 80 organic compounds in 14 famihes shows absolute errors of 0.15 percent and 2.3 percent for the lower and upper hmits, respectively. The upper limit predic tion should not be used for ethers. 

A third fundamental type of laboratory distillation, which is the most tedious to perform of the three types of laboratory distillations, is equilibrium-flash distillation (EFV), for which no standard test exists. The sample is heated in such a manner that the total vapor produced remains in contact with the total remaining liquid until the desired temperature is reached at a set pressure. The volume percent vaporized at these conditions is recorded. To determine the complete flash curve, a series of runs at a fixed pressure is conducted over a range of temperature sufficient to cover the range of vaporization from 0 to 100 percent. As seen in Fig. 13-84, the component separation achieved by an EFV distillation is much less than by the ASTM or TBP distillation tests. The initial and final EFN- points are the bubble point and the dew point respectively of the sample. If desired, EFN- curves can be established at a series of pressures. 

TBP cut point between the heavy distillate and the bottoms = 650°F. Percent overflash = 2 volume percent of feed. 

In general, the effect of percentage of mixer volume occupied by the batch on the adequacy of mixing shoiild be borne in mind, particularly when any change from the recommended volume percent is considered. 

Flammable Limits Flammable limits, or the flammable range, are the upper and lower concentrations (in volume percent) which can just be ignited by an ignition source. Above the upper limit and below the lower hmit no ignition will occur. Data are normally reported at atmospheric pressure and at a specified temperature. Flammable hm-its may be reported for atmospheres other than air and at pressures other than atmospheric. 

Much later (Marcinkowsky and Berty 1973) it was proven that ethane did indeed have an effect. In the study of the inhibitor action of chlorinated hydrocarbons it was discovered that these compounds chlorinate the silver catalyst and ethane removes the chlorine from the catalyst by forming ethyl chloride. Since the inhibitor was in the 10 ppm range and similar quantities were used from the ethane present in about one volume percent, the small difference could not be calculated from material balance. The effect of ethane was only noticed as significant by the statistics, which justifies the statement made by Aris (1966) that, The need for sophistications should not be rejected unsophisticatedly. ... 

Comparison of the volume/volume composition data with the relative pressure data shows that although C2-C4 hydrocarbons are present to the greatest volume percent, their actual pressures are an order of magnitude lower than the C5 plus hydrocarbons. Hence, the C5 plus hydrocarbons would be adsorbed in preference to the C2-C4 hydrocarbons and would displace them over a number of cycles. It is apparent therefore that the C5 plus hydrocarbons must be considered the primary target gases for pre-adsorption in guard bed systems... 

Where the oxidant concentration is continually monitored, a safety margin of at least 2 volume percent below the measured worst credible case LOG shall be maintained, unless the LOG is less than 5 volume percent, in which case, the equipment or piping shall be operated at no more than 60% of the LOG. 

Wliere the oxidant concentration is not continually monitored, the oxidant concentration shall be maintained at no more than 60% of the LOG or 40% of the LOG if the LOG is below 5 volume percent. If the oxidant concentration is not continually monitored the oxidant concentration shall be checked on a regularly scheduled basis. 

There is a relationship between the MIL of a gas or vapor and the quenching distance, as shown in Figure 4-5 (van Dolah and Burgess 1974). These data are for a large variety of chemicals with oxygen varying between 21 and 100 volume percent and pressure between 0.1 to 2 atmospheres. 

Notr The above data are from tests in a straight 3-inch diameter pipe using a test gas consisting of 4.3 volume percent propane mixture in air, initially at 23 psia. 

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