Pipehnes

The initial biogas recovered is an MHV gas and is often upgraded to high heat value (HHV) gas when used for blending with natural gas suppHes. The aimual production of HHV gas ia 1987, produced by 11 HHV gasification facihties, was 116 x 10 m of pipehne-quaUty gas, ie, 0.004 EJ (121). This is an iacrease from the 1980 production of 11.3 X 10 m . Another 38 landfill gas recovery plants produced an estimated 218 x 10 m of MHV gas, ie, 0.005 EJ. Additions to production can be expected because of landfill recovery sites that have been identified as suitable for methane recovery. In 1988, there were 51 sites ia preliminary evaluation and 42 sites were proposed as potential sites (121). 

Economic Pipe Diameter, Laminar Flow Pipehnes for the transport of high-viscosity liquids are seldom designed purely on the basis of economics. More often, the size is dictated oy operability considerations such as available pressure drop, shear rate, or residence time distribution. Peters and Timmerhaus (ibid.. Chap. 10) provide an economic pipe diameter chart for laminar flow. For non-Newtouiau fluids, see SkeUand Non-Newtonian Flow and Heat Transfer, Chap. 7, Wiley, New York, 1967). 

Section 10 of this Handbook describes the use of orifice meters for flow measurement. In addition, orifices are commonly found within pipelines as flow-restric ting devices, in perforated pipe distributing and return manifolds, and in perforated plates. Incompressible flow through an orifice in a pipehne as shown in Fig. 6-18, is commonly described by the following equation for flow rate Q in terms of pressure drop across the orifice Ap, the orifice area A, the pipe cross-sectional area A, and the density p. 

When fluid flows past objects or through orifices or similar restrictions, vortices may periodically be shed downstream. Objects such as smokestacks, chemical-processing columns, suspended pipehnes, and electrical transmission lines can be sul ected to damaging vibrations and forces due to the vortices, especially if the shedding frequency is close to a natural vibration frequency of the objecl. The shedding can also produce sound. See Krzywoblocki (Appl. Mech. Rev., 6, 39 397 [1953]) and Marris (J. Basic Eng., 86, 185-196 [1964]). 

Liquefied petroleum gas (LPG) is the subject of API Standard 2510, The Design and Construction of Liquefied Petroleum Gas Installations at Marine and Pipehne Terminals, Natural Gas Processing Plants, Refineries, and Tank Farms. This standard in turn refers to ... 

Petroleum pipe hues before 1969 were built to ASA (now ANSI) Standard B31.4 for liquids and Standard B31.8 for gas. These standards were seldom mandatoiy because few states adopted them. The U.S. Department of Transportation (DOT), which now has responsi-bihty for pipe-line regulation, issued Title 49, Part 192—Transportation of Natural Gas and Other Gas by Pipeline Minimum Safety Standards, and Part 195—Transportation of Liquids by Pipehne. These contain considerable material from B31.4 and B31.8. They allow generally higher stresses than the ASME Pressure Vessel Code would allow for steels of comparable strength. The enforcement of their regulations is presently left to the states and is therefore somewhat uncertain. 

Introduction There are two types of gas-hqiiid contactors where the liquid is deliberately dispersed. In the most common, a spray nozzle is used to generate droplets. A second t me is the pipehne contactor, where the entrainment generated by flowing gas generates the droplets. 

Breakup in a highly turbulent field (L/velocity) ". This appears to be the dominant breakup process in distillation trays in the spray regime, pneumatic atomizers, and high-velocity pipehne contactors. 

Pressure Development Overpressure in a UVCE results from turbulence that promotes a sudden release of energy. Tests in the open without obstacles or confining structures do not produce damaging overpressure. Nevertheless, combustion in a vapor cloud within a partially confined space or around turbulence-producing obstacles may generate damaging overpressure. Also, turbulence in a jet release, such as may occur with compressed natural gas discharged from a ruptured pipehne, may result in blast pressure. 

Explosion isolation can also be effected by rapid action barrier valves. At present, they can be arranged only in horizontal pipehnes and are suitable, in general, only for streams with a small amount of dust. Such valves are thus frequently used to protect ventilation lines. As a certain explosion overpressure is necessaiy to close such valves, a distinction is made between self-actuated and externally actuated barrier valves (Fig. 26-46). 

Most natural gas is substantially free of sulfur compounds the terms. sweet and. sour are used to denote the absence or presence of HgS. Some wells, however, dehver gas containing levels of hydrogen sulfide and other sulfur compounds (e.g., thio enes, mercaptans, and organic sulfides) that must be removed before transfer to commercial pipehnes. Pipehne-company contracts typically specify maximum allowable Emits of impurities HgS and tot sulfur compounds seldom exceed 0.023 and 0.46 g/m (1.0 and 20.0 gr/100 std fF),... 

LPG is widely used for domestic service, supplied either in tanks or by pipehnes. It is also used to augment natural-gas deliveries on peak days and by some industries as a standby fuel. 

The monetization of remote natural gas has been a key economic driver for catalysis research over the past 20 years. Significant reserves of natural gas exist in remote locations, distant from available gas pipehnes, which cannot be readily brought to market. The conversion of these resources to higher-valued, transportable products, such as methanol or polyolefins can allow the economical utilization of these stranded assets. Other low-valued natural gas streams, such as associated gas from oil production, could also provide feedstocks to such a technology. The conversion of remote gas, typically valued at US 0.50-1.50 per MMBTU, into polyolefins, valued at more than US 1000/t, via methanol has sparked the development of several MTO technologies. 

When the system which was to be linked to the autosampler system was purchased, it was found that the conductivity cell was excessively large and primarily designed to be fitted to a A" pipehne for analytical purposes this was clearly too large. However, the pH cell provided an Ingold standard electrode system with dimensions which allowed it to be placed within the conductivity sensor, as shown in Fig. 7.21. It is therefore possible to configure a flow cell in which the conductivity sensor houses the pH electrode. The latter also serves to take up most of the cell volume so that the wash-out requirements are not too excessive. The cell is filled by taking a sample from the autosampler with pump 1 hquid fills the cell and overflows via the weir arrangement and the top of the cell. 

PURASPEC A process for pmilying gaseous and hquid hydrocarbons by the use of fixed beds of catalysts and adsorbents which remove imprrrities by chemical reaction. Developed in 1990 by ICI Katalco to enable natural gas and natrrral gas hqrrids to meet pipehne speci-ficatiorrs. Installed in approximately 60 plants worldwide in 1996. 

Dense-phase (low-velocity slug-flow) solids mass flow = 6th-1, air mass flow =0.065kgs-1, solids loading = 26, pipehne pressure drop = 120 kPa, air velocity = 2.9 to 6.3 ms-1. 

The test of BASYC tubes as small-vessel prosthesis for other artificial pipehnes (arteries, veins, lymph, and urine leading vessels) is under progress. Initial results of the implantation of BASYC material into jugular veins of 10 white rats showed no complications such as wall-proliferation, stenosis or thrombosis. A normal blood flow through the interposition as well as the formation of connective tissue around it were detectable 4 and 12 weeks, respectively, after the operation [124]. 

When raw natural gas comes to the surface it is often saturated with heavier hquids. Should the gas be cooled, in an undersea-pipeline for instance, then some of the heavier components condense to form a slug of liquid in the pipehne. These liquids are removed in a series of large pipes known as a slug catcher - Figure 3.1. 

By pipehne when sufficient volumes of product or feed are to be moved. This is usually used when large numbers of producers and users are in a region (e.g. Western Europe). 

In looking for production hnes to close, companies should consider several constraints. It may, for instance, be hard to close lines that are physically integrated with feedstock, so optimum candidates for closure either wiU not be integrated, or wiU be hnked to feedstock pipehnes that would permit alternative uses of the feedstock should they be closed. 

R. A. Taylor, W.R. Penney, and H.X. Vo, Scale-up methods for fast competitive chemical reactions in pipehne mixers, paper number 188c, written and presented at the 1998 Annual AIChE Meeting at Miami Beach, 1998. 

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