Total hydrocarbons

Ref 11. Total hydrocarbons (THC) reported as methane. Maximum 5 p.L/L nitrogen only. ... 

Value noted in combined total hydrocarbons and carbon dioxide. Value noted is combined carbon dioxide and carbon monoxide. ... 

Products of Incomplete Combustion Emission Limits. Products of iacomplete combustion typically are not directly measured duting the trial bum. Instead, levels of carbon monoxide (qv) emissions are used as an iadication of combustion efficiency. High combustion efficiencies are assumed to result ia acceptable levels of products of incomplete combustion. If carbon monoxide emissions are measured at less than 100 ppmv dry basis, the standard is met. However, if emissions are greater than 100 ppmv, no more than 20 ppmv of total hydrocarbons (qv) are allowed at the iaciaerator stack duting the trial bum. 

Each k is given by an Arrhenius expression, k = A exp(—F/i T), and the fraction of the tightly bound component is a parameter. For the high temperature results in Figure 6, some charring of toluene was observed at the highest wall temperature (790°C). The fraction of toluene remaining in the bed was deterrnined from gas-phase total hydrocarbon, O2, and CO2 measurements. 

Fig. 8. Transient NO emissions at synthetic wastes nitrogen contents of (D), 1% ( ), 3% and (0)> 10%, where the % of O2 is 2ero. Aniline is used as a nitrogen source and toluene is used to keep the total hydrocarbon weight fixed at 35 g (29).

In the United States, the Compressed Gas Association Hsts nine grades of nitrogen, differentiated by oxygen content, dew point, total hydrocarbon content, and other contaminant levels (25). These grades, more often specified in government than commercial contracts, are shown in Table 3. 

Gaseous and Hquid nitrogen Nitrogen, min % (mol/mol) Oxygen Water, ppm (v/v) Dew point, °C Total hydrocarbon a content... 

Total Hydrocarbon Gontent. The THC includes the methane combined in air, plus traces of other light hydrocarbons that are present in the atmosphere and escape removal during the production process. In the typical oxygen sample, methane usually constitutes more than 90% of total hydrocarbons. The rest may be ethane, ethylene, acetylene, propane, propylene, and butanes. Any oil aerosol produced in lubricated piston compressor plants is also included here. 

A flame-ionization, total hydrocarbon analyzer determines the THC, and the total carbon content is calculated as methane. Other methods include catalytic combustion to carbon dioxide, which may be deterrnined by a sensitive infrared detector of the nondispersive type. Hydrocarbons other than methane and acetylene are present only in minute quantities and generally are inert in most appHcations. 

Most of the hydrocarbon emissions from iron and steel facilities are not captured by TRI. The EPA Office of Air Quality Planning and Standards has compiled air pollutant emission factors for determining the total air emissions of priority pollutants (e.g., total hydrocarbons, SO, NO, CO, particulates, etc.) from many iron and steel manufacturing sources. 

The total hydrocarbon reduction efficiency for the Rotor/Concentrator is the adsorption efficiency of the Rotor/Concentrator times the destruction efficiency of the oxidizer. 

An estimate is required of the total hydrocarbon concentration 300 meters downwind of an expressway on an overcast day with wind speed 4 m/s. Tlie expressway runs norlli-south and the wind is from tlie west. Tlie measured traffic flow is 8000 vehicles per hour during tlris rush hour, and the average speed of the velucles is 40 mph. At tlris speed tlie average vehicle is expected to... 

The definitions above are an abbreviated version of those used in a veiy complex and financially significant exercise with the ultimate goal of estimating resei ves and generating production forecasts in the petroleum industry. Deterministic estimates are derived largely from pore volume calculations to determine volumes of either oil nr gas in-place (OIP, GIP). This volume when multiplied by a recovery factor gives a recoverable quantity of oil or natural gas liquids—commonly oil in standard barrels or natural gas in standard cubic feet at surface conditions. Many prefer to use barrels of oil equivalency (BOE) or total hydrocarbons tor the sum of natural gas, natural gas liquids (NGL), and oil. For comparison purposes 6,000 cubic feet of gas is considered to be equivalent to one standard barrel on a British thermal unit (Btu) basis (42 U.S. gallons). 

FIGURE 16.9 Model fits at the standard process conditions (T = 230°C, P = 20 bar, H2/CO feed molar ratio = 2.1, GHSV = 5,000 cm3(STP)/h/gcat) in terms of n-paraffins, a-olefins, and total hydrocarbons. 

FIGURE 16.10 Experimental and calculated ASF product distributions in terms of total hydrocarbons at five different process conditions. 

For the range of industrially relevant conditions, the developed model could accurately predict both the observed CO conversion and the products distribution up to n = 49, in terms of total hydrocarbons, n-paraffins, and a-olefins. In particular, using thirteen adaptive parameters, the model is able to describe the typical deviations of the product distribution from the ASF model, i.e., the methane high selectivity, the low selectivity to C2 species, and the change of the slope of the ASF plot with growing carbon number. Accordingly, the present model can be applied to identify optimized process conditions that are suitable to grant the desired conversion with the requested products distribution. 

Zsolnay and Kiel [26] have used flow calorimetry to determine total hydrocarbons in seawater. In this method the seawater (1 litre) was extracted with trichlorotrifluoroethane (10 ml) and the extract was concentrated, first in a vacuum desiccator, then with a stream of nitrogen to 10 pi A 50 pi portion of this solution was injected into a stainless steel column (5 cm x 1.8 mm) packed with silica gel (0.063-0.2 mm) deactivated with 10% of water. Elution was effected, under pressure of helium, with trichlorotrifluoroethane at 5.2 ml per hour and the eluate passed through the calorimeter. In this the solution flowed over a reference thermistor and thence over a detector thermistor. The latter was embedded in porous glass beads on which the solutes were adsorbed with evolution of heat. The difference in temperature between the two thermistors was recorded. The area of the desorption peak was proportional to the amount of solute present. 

Zsolnay A (1974) Determination of aromatic and total hydrocarbon content in submicrogram and microgram quantities in aqueous systems by means of high-performance liquid chromatography. Special publication no. 409. National Bureau of Standards, Washington, DC, p 119... 

The yield was rather insensitivip to the H /CO ratio in this range. However, the aromatics in increased sharply with decreasing 7 CO ratio, reaching 94% at the 7CO ratio of 1/2 the aromatics in total hydrocarbon increased from 11% at 2/1 ratio to 18% at 1/2 ratio. More importantly, formati°n... 

The detailed model was constructed as described by Carslaw et al. (1999, 2002). Briefly, measurements of NMHCs, CO and CH4 were used to define a reactivity index with OH, in order to determine which NMHCs, along with CO and CH4, to include in the overall mechanism. The product of the concentration of each hydrocarbon (and CO) measured on each day during the campaign and its rate coefficient for the reaction with OH was calculated. All NMHCs that are responsible for at least 0.1% of the OH loss due to total hydrocarbons and CO on any day during the campaign are included in the mechanism (Table 2). Reactions of OH with the secondary species formed in the hydrocarbon oxidation processes, as well as oxidation by the nitrate radical (NO3) and ozone are also included in the... 

---