Gas Storage, Shipping, and Pipeline Transport

Larger quantities of industrial gas products (greater than 10 tons per day) are usually supplied either by a dedicated plant or a pipeline system. A dedicated plant is an industrial gas manufacturing plant located adjacent to a customer s site. The primary output is dedicated to that specific customer. 

This is commonly known in the industrial gas industry as an on-site plant (although it is often designated by the customer as an off-site plant ). When multiple customers in the same geographic area require product of approximately the same specifications, an industrial gas company will sometimes supply these customers from a single industrial gas plant and deliver the product by pipeline. Large pipeline systems often have multiple gas plants supplying product into the pipeline and as many as several dozen customers drawing product from the system. 

Industrial gases sold in small quantities are liquefied at the point of manufacture, stored in cryogenic storage vessels, shipped over the road, and stored as a liquid at the point of use until needed. When required, the product is drawn from storage, vaporized, and used in the customer s process. Cryogenic storage involves the use of high performance vessels that reduce the boil-off rate of product to less than 0.1%per day [1]. 

Tanks may be constructed either in spherical or cylindrical shapes, although the cylindrical shape is more common. The most economical configuration is cylindrical with either dished, elliptical, or hemispherical heads. Orientation can be either horizontal or vertical. 

Note The tank sizes listed are standard size units. Larger tanks are specially designed for other applications requiring more volume. Tanks have been built for storage of liquefied gas exceeding 20,000 U.S. gal. 

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Once the H2 is available either as a pressurized gas or as a cryogenic liquid, it still has to be stored and transported to the users. In addition to transportation and storage, there are also infrastructure expenses. A National Renewable Energy Laboratory (NREL) reference provides dollar cost figures per kilogram of H2 These total costs include energy, freight, labor, and capital costs and have been developed for truck, rail, ship, and pipeline transportation of both gas and LH2 at various flow rates and over a variety of... 

If transport to the storage site by pipeline proves to be impracticable or too expensive, there are alternatives to be evaluated. At atmospheric pressure, cryogenic carbon dioxide ( dry-ice ) does not melt, but sublimes at — 78 °C. Thus, in principle, it can be carried as a solid in refrigerated trucks or ships. This would, however, require freezing at the production plant and then vaporization at the storage site before injection of the gas. Both of these activities are energy intensive. In addition, dry-ice is difficult to handle in quantity. A more feasible mode of transport depends on the fact that the gas can be liquefied under high pressure. At 22 °C, the vapour pressure over the liquid is around 6 MPa. It is therefore possible to convey carbon dioxide as a liquid in pressurized tankers, provided that the temperature is well controlled. 

Storage and Transportation. Handling requirements are similar to Hquefied petroleum gas (LPG). Storage conditions are much milder. Butylenes are stored as Hquids at temperatures ranging from 0 to 40°C and at pressures from 100 to 400 kPa (1—4 atm). These conditions are much lower than those required for LPG. Their transportation is also similar to LPG they are shipped in tank cars, transported in pipelines, or barged. 

Liquefied Natural Gas (LNG) plants can be categorized as peakshaving or baseload. Peakshaving LNG plants are built at the consumer end of natural gas pipelines to accumulate LNG in storage tanks for later vaporization and sendout into the local grid during periods of peak demand. Baseload LNG plants provide a steady base supply of natural gas to utiHty companies, generally by transportation of LNG by ship from one country to another. 

The largest accidents in terms of casualties in the energy field are connected with the collapse of hydro dams. Some 2500 people perished, for example, in a single dam failure in Macchu, India. There are also, as we know, severe accidents connected with the transport and storage of gas, the mining of coal, and the shipping of oil. A gas pipeline explosion in Guadalajara in Mexico killed 200 people in 1992. 

Once CO2 is separated from other flue gas components, it must be compressed and transported to a storage site. The large volumes make transport by pipeline the lowest-cost option. Several pipelines in the United States transport large quantities of CO2 from naturally occurring sources to enhanced oil recovery projects in the western United States. These pipelines operate at approximately 150 bar so the CO2 is transported as a supercritical dense-phase fluid. This technology is well estabhshed and needs little technology development. Other transport methods, such as liquid by truck, rail, or ship, are possible, but the costs of such operations would radically affect the cost of CO2 mitigation. 

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