Hydrocarbons losses

Implementation of P2 (pollution prevention) measures can yield both economic and environmental benefits. However, a balance on energy usage and environmental impacts may have to be struck. New refineries should be designed to maximize energy conservation and reduce hydrocarbon losses. 

Producing relatively accurate dry-weight values for heavy petroleum hydrocarbons but questionable dry weight values for lighter, more volatile compounds. Note Different labs dry the samples in different ways and a sample with lots of lighter-fraction hydrocarbons is more prone to hydrocarbon loss the variable loss of volatile hydrocarbons in a drying step is therefore an additional area of lab and data variability). 

Gong, Q and K. L. Demerjian, Hydrocarbon Losses on a Regenerated Nafion Dryer, J. Air Waste Manage. Assoc., 45, 490-493 (1995). 

The concept of reactivity scales is based on ranking organics in terms of their potential for ozone production. A number of different parameters have been used to rank organics by their reactivity, including observed rates of reaction, product yields, and effects observed from irradiated VOC-NO. mixtures. For example, the rates of 03 or N02 formation or the hydrocarbon loss have been used to develop reactivity scales, as have the yields or dosages of products such as 03 and PAN in... 

Traces of hydrocarbons have been added to slowly reacting H2 + 02 mixtures in aged boric-acid-coated vessels at 480°-500°C. Measurements of hydrocarbon loss and H20 formation have enabled relative velocity constants for the attack of the radicals H, O, OH, and H02 on the additive to be assessed for CH,t and C2H6. With CHhy the results also show that CHS radicals react at almost equal rates with H2 and 02 at 500 mm. Hg pressure, and that the reaction with 02 appears to have both second- and third-order components. Detailed analyses of the reaction products obtained with ethane and neopentane enable the reactions of the radical produced in the primary attack to be elucidated, and mechanisms to account for the various products are given. 

Except for methane, the kinetic studies have been carried out using 0.1% mole of hydrocarbon, so that the relative concentrations of H, O, OH, and H02 were not disturbed. However, in the analytical work 1% of the additive has been used to allow accurate measurement of the minor products. By presenting the concentration of product as a function of either hydrocarbon loss or pressure change, it is possible to distinguish primary, secondary, and tertiary products. 

Some of the CO2, N2 and N2O gases produced within the Bay and included in this term are carried offshore dissolved in the water rather than actually exchanged across the air-water interface in the Bay. Hydrocarbon loss includes volatilization and respiration. If allocthonous DOC is carried conservatively through the Bay, the offshore loss would rise to about 27 % of input and the flux to the atmosphere would fall to 73 %. 

Drying H20/HC H20/air Hydrocarbon drying Air drying Feasible Practical to about — 10°C dew point Hydrocarbon loss should be minimized... 

IK. Convert Blowdown Stacks Replace existing atmospheric blowdown stacks with flares. This reduces untreated hydrocarbon losses to the atmosphere, but creates criteria pollutants. 

Krooss, B.M., Leythaeuser, D. and R.G. Schaefer, 1992. The quantification of diffusive hydrocarbon losses through cap rocks of natural gas reservoirs - a reevaluation. The American Association of Petroleum Geologists Bulletin, Vol. 76, no. 3, pp. 403—406 Kruseman, G.P., De Bidder, N.A. and J.M. Verweij, 1990. Analysis and evaluation of pumping test data. International Institute for Land Reclamation and Improvement Publication 47, Wageningen, The Netherlands, 377 pp. 

Krooss, B.M., Leythaeuser, D. and Schaefer, R.G. 1992. The quantification of diffusive hydrocarbon losses through cap rocks of natural gas reservoirs - a reevaluation. Am. Assoc. Pet. Geol. Bull., 76 403-406. 

Potential hydrocarbon losses from the overpressuring of operating vessels are controlled first by staged computer alerts and/or manual alarms to provide for correction of the condition. If the overpressure exceeds a second set point, pressure relief valves vent the vessel contents to a flare release system. The flare system provides a means of controlled burning of hydrocarbon vapors at a nonhazardous point to avoid fire or explosion risks. Smoke problems from flares are avoided by more efficient designs that use multiple nozzles and low pressure operation to promote clean combustion [57]. Greenhouse gas concerns should more frequently stimulate an interest in energy recovery options from flared hydrocarbons. 

C1RO2 + P Hydrocarbon loss and product formation R02 -f- Loss Product loss... 

Ferrocene has also been incorporated in zeolite hosts [244, 255] and hydrocarbon loss on heating and oxidation to ferricinium cation were observed. Similarly, substituted ruthenocenes were also investigated [256, 257]. The ring opening polymerization of a [l]silaferrocenophane within the channels of mesoporous silica (MCM-41) gave precursors of magnetic iron nanostructures [257a,b]. 

For total acid gas concentration above 10%, unfavorable CO2/H2S ratios or mercaptan concentration above 100 ppm, the costs for the treating line up can become the major part of the overall surface facilities costs. If significant concentrations of C3-I-hydrocarbons are present, the hydrocarbon losses towards the Claus unit can become substantial. 

Improving the solubility of mercaptans, H2S and CO2 in the solvent. If this is achieved, the solvent circulation rates can be reduced and the hydrocarbon losses are reduced. 

Often, two reactors in series are used to increase on-stream efficiency. The catalyst in one reactor can be replaced while the other continues to operate. The reactor effluent (isomerate) flows to a stabilizer. A caustic scrubber removes HCl from the separated light gases. The stabilized liquid product comprises a near-equilibrium mixture of n-butane and isobutanes, plus a small amount of heavier hydrocarbons. Losses due to cracking are less than 1 wt%. 

Fuel delivery systems must meet California Air Resources Board (CARB) regulations, including Low Emissions Vehicle LEV II, which goes into effect in 2004 and limits evaporative hydrocarbon emissions to 0.5 g/day maximum—a 75 percent rednction from the regulation in 2000. Other state regulations for evaporative hydrocarbon emissions have been developed. Test methods to measure evaporative hydrocarbon emission as hydrocarbon loss in materials for components and the entire fuel defivery system are standardized by a joint effort between automotive and materials companies. The methods inclnde... 

Losses of valuable or hazardous components through waste streams. The chemical analysis of plant waste streams, both to air and water, will indicate whether valuable materials are being lost. Adjustment of air/fuel ratios in furnaces to minimize unburned hydrocarbon losses and to reduce nitrogen-oxide emissions is one such example. 

The xylene losses introduced into the environment are probably made up of some 0.5 million t from solvent losses, about 2 million t from losses during the production, transportation and processing of petroleum as a portion of the total hydrocarbon losses, and some 0.5-1 million t as a component of automobile exhaust gases. Compared with these emissions, the losses during transportation and distribution of gasoline (estimated worldwide at 10,000 t) and the losses in the chemical industry (estimated at less than 50,000 t) are relatively low, also because the vapour pressure of the Cg-aromatics is lower than that of benzene and toluene. As mentioned, the total annual load imposed on the sea is probably some 600,0001 xylenes as part of petroleum fractions. 

Several factors influence the selection of a pipehne repair method. Generally, new technologies are not readily accepted by O G operators because, in the absence of established service track records, the risk of hydrocarbon loss in the event of failure is deemed to be imacceptably high. Moreover, the severity of the pipeline damage, location, operating and environmental conditions, fluid composition, cost and urgency for repair aU contribute to the ultimate selection of a repair method. 

A third important area for gas separation is the removal of water vapor from air or from hydrocarbons. This separation is easily accomplished using adsorption, but the adsorbent beds require periodic regeneration. Membranes, which do not require this regeneration, show selectivities over air and hydrocarbons of thousand to one. Hydrocarbon losses, which are significant now, should improve as the membranes evolve. 

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