Compressed pipeline

The hydrogen plants described above serve as excellent platforms for pre-combustion CO2 capture because most of the feedstock carbon has been already converted to CO2 and separated as a relatively pure stream, ready for dehydration, compression, pipeline transport and geologic storage. The result is fossil fuel-derived hydrogen that has been decarbonized via pre-combustion CO2 capture. 

From the above plot, it can be seen that the recovery factor for gas reservoirs depends upon how low an abandonment pressure can be achieved. To produce at a specified delivery pressure, the reservoir pressure has to overcome a series of pressure drops the drawdown pressure (refer to Figure 9.2), and the pressure drops in the tubing, processing facility and export pipeline (refer to Figure 9.12). To improve recovery of gas, compression facilities are often provided on surface to boost the pressure to overcome the pressure drops in the export line and meet the delivery pressure specified. 

Condensable hydrocarbon components are usually removed from gas to avoid liquid drop out in pipelines, or to recover valuable natural gas liquids where there is no facility for gas export. Cooling to ambient conditions can be achieved by air or water heat exchange, or to sub zero temperatures by gas expansion or refrigeration. Many other processes such as compression and absorption also work more efficiently at low temperatures. 

Sales gas, which is typically made up of methane (CH ) and small amounts of ethane (C2Hg), can be exported by refrigerated tanker rather than by pipeline and has to be compressed by a factor of 600 (and cooled to -150°C). This is then termed Liquefied Natural Gas (LNG). 

Within the project box, the cashflow oi the project (or other investment opportunity) is the forecast of the funds absorbed and the money generated during the project lifetime. Take, for example, the development of an oil field as the investment opportunity. Initially the cashflow will be dominated by the capital expenditure (capex) required to design, construct and commission the hardware for the project (e.g. platform, pipeline, wells, compression facilities). 

Drilling Engineering Drilling and completion costs Capital costs -platforms -pipelines -compression/pumps... 

By-product water formed in the methanation reactions is condensed by either refrigeration or compression and cooling. The remaining product gas, principally methane, is compressed to desired pipeline pressures of 3.4—6.9 MPa (500—1000 psi). Einal traces of water are absorbed on siHca gel or molecular sieves, or removed by a drying agent such as sulfuric acid, H2SO4. Other desiccants maybe used, such as activated alumina, diethylene glycol, or concentrated solutions of calcium chloride (see Desiccants). 

Natural gas upgra ding economics may be affected by additional factors. The increasing use of compressed natural gas (CNG) directiy as fuel in vehicles provides an alternative market which affects both gas price and value (see Gasoline and other motor fuels Gas, natural). The hostility of the remote site environment where the natural gas is located may contribute to additional costs, eg, offshore sites require platforms and submarine pipelines. 

Worldwide, approximately 180, 000 t/yr acetylene product is recovered as a by-product within olefin plants. This source of acetylene is expected to increase as plant capacity and furnace temperature increase. The recovery may include compression and transfer of the acetylene product via pipelines directly to the downstream consumer. 

Essentially all of the methane [74-82-8] is removed ia the demethanizer overhead gas product. High recovery of ethane and heavier components as demethanizer bottoms products is commonplace. The work that is generated by expanding the gas ia the turboexpander is utilized to compress the residue gas from the demethanizer after it is warmed by heat exchange with the inlet gas. Recompression and deUvery to a natural gas pipeline is performed downstream of the plant. A propane recovery of 99% can be expected when ethane recoveries are ia excess of 65%. 

Sulfur and Chlorine Pipelines. Underground sulfur is melted by superheated water and then piped as Hquid to the surface with compressed air. At the surface, molten sulfur is transported by heated pipeline to a storage or shipping terminal. One such pipeline, located under 15 m of water in the Gulf of Mexico, is insulated and surrounded by steel casing to which are strapped two 130-mm dia pipelines that carry return water from the deposit. The superheated water is carried from shore to the deposit in a 63.5-mm dia pipe inside the pipeline that carries the molten sulfur (21). 

A 2.54-cm Styrofoam plastic foam with thermal conductivity of ca 0.03 W/ (m-K) (0.21 (Btu-in.)/(ft-b°F)) is equivalent to 61 cm of gravel. Any synthetic foam having compressive strength sufficiently high and thermal conductivity sufficiently low is effective. However, the resistance of PS-type foams to water, frost damage, and microorganisms in the sod makes them especially desirable. An interesting and important appHcation of this concept was the use of Styrofoam in the constmction of the Alaska pipeline. In this case, the foam was used to protect the permafrost. 

In chemical process applications, one-dimensional gas flows through nozzles or orifices and in pipelines are the most important apphcations of compressible flow. Multidimensional external flows are of interest mainly in aerodynamic applications. 

Adiabatic Frictionless Nozzle Flow In process plant pipelines, compressible flows are usually more nearly adiabatic than isothermal. Solutions for adiabatic flows through frictionless nozzles and in channels with constant cross section and constant friction factor are readily available. 

Because the value of Z for natural gas is significantly less than unity at ambient temperatures and at pressures greater than 1 MPa (145 psia), the compressibility must be taken into account in gas measurement gas purchased at high line pressure will fflve a greater volume when the pressure is reduced than it would if the gas were ideal. Natural gas pipeline operators use a.. supercompre.s.sihility faclor, also called Z, out defined as... 

The following analysis enables one to calculate the diameter of a pipeline transporting any compressible fluid. The required inputs are volumetric flow rate, the specific gravity of the gas relative to air, flow conditions, compressibility factor Z where Z is defined by nZRT = PV, the pressure at the point of origin and the destination, the pipe length, and pipe constants such as effective roughness. The working equations have been obtained from the literature. Since the friction factor... 

Compressors are used whenever it is necessary to flow gas from a lower pressure to a higher pressure system. Flash gas from low-pressure vessels used for multistage stabilization of liquids, oil treating, water treating, etc., often exists at too low a pressure to flow into the gas sales pipeline. Sometimes this gas is used as fuel and the remainder flared or vented. Often it is more economical or it is necessary for environmental reasons to compress the gas for sales. In a gas field, a compressor used in this service is normally called a flash gas compressor. Flash gas compressors are normally characterized by low throughput rate and high differential pressure. 

Poppet valves are typically used for low compression ratio applications, such as pipeline booster compressors. As the pressure differential increases across each of the individual poppets, they lift and allow gas to pass through the flow openings in the stop plate. 

An entirely different diesel hazard is compression of a pocket of air and flammable vapor trapped in a vessel or pipeline by a column of liquid. If the pressure of the liquid rises, the air is compressed, and the heat developed may heat the vapor above its auto-ignition temperature [13]. 

Compressed air lines are very susceptible to a combustion gciienition e.xplosion, fueled by oil or cliar on tlie pipe walls. E.xplosions in pipelines c ui cause considerable damage. Pipelines witliin wliich gas, vapor, or dust explosions can occur must be designed to have sufficient mechanical streiigtli to withstand pressure or stress beyond tliat required by the application. 

The technologies for routine handling of large quantities of hydrogen have been developed in the chemical industry. Hydrogen can be liquefied at low temperature (-253°C) and delivered by cryogenic tank truck or compressed to high pressure and delivered by truck or gas pipelines. 

The industry has developed higher compression tanks to expand the range, and more fast-fill stations are becoming available, yet the prospects of the majority of service stations adding compressed natural gas refueling anytime in the near future are bleak. The oil companies, which control most of the service stations and over 60 percent of America s natural gas reserves, are not eager to make the massive infrastructure investment to cannibalize the billions of dollars they have tied up in refineries, pipelines, and service sta-... 

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