Gas plant

In this section gas processing will be described in the context of site needs and evacuation, i.e. how gas may be processed for disposal or prior to transportation by pipeline to a downstream gas plant. Gas fractionation and liquefaction will be described in Section 10.1.4 Downstream Gas Processing . 

NFPA StandarcT59, Standard ror the Storage and Handling of Liquefied Petroleum Gases at Utility Gas Plants... 

High-Temperature Coke (1173 to 1423 K or 1652 to 2102°F.) This type is most commonly used in the United States nearly 20 percent of the total bituminous coal consumed is used to make high-temperature coke for metallurgical applications. About 99 percent of this type of coke is made in slot-type recovery ovens. Blast furnaces use about 90 percent of the production, the rest going mainly to foundries and gas plants. 

While comparison of the absolute capital costs and costs of electricity among different power systems is difficult and uncertain, the structure of these costs is rather typical, and the costs of component units are usually within known ranges. For an oxygen-blown IGCC power system, the breakdown of the capital cost for the four component units is air separation plant (11 to 17 percent), fuel gas plant (33 to 42 percent), combined-cycle unit (32 to 39 percent), and balance of plant (2 to 21 percent). The breakdown of the cost of elec tricity is capital charge (52 to 56 percent), operating and maintenance (14 to 17 percent), and fuel (28 to 32 percent). 

Improving the economics of gas plant design, construction, and operations is essential to ensure the approval of future de-bottlenecking, capacity expansion, and new projects. The economics include not only capital investment, life cycle operations, and maintenance costs, but also the monetary equivalents of safety, reliability, and availability. 

The trend in gas plant design has been to maximize train capacity in an effort to take advantage of the economy of size. At the same time, gas plant designers are constrained by the maximum size of processing equipment of proven design. Table 3-4 shows the trend in gas plant train sizes in the last three decades. 

Onshore or offshore gas plants are designed for either LNG rejection and gas injection, or LNG rejection and transmission for sale. In the case of offshore plants, onshore facilities further process the natural gas before transmission for sale. In either case, natural gas must be treated and then refrigerated to make rejection of heavy hydrocarbons possible. In plants where natural gas is treated for sale purposes, water and hydrocarbon dew points of the gas must also be controlled. 

Gas plant train sizes (thousand tons / year)... 

In chemical plants, turboexpanders are used to produce refrigeration for cold box installations. In all except energy recovery applications, there are gas-to-gas heat exchangers downstream of the turboexpander. Figure 6-14 recaps a process flow diagram of a natural gas processing gas plant. 

In natural gas applieations, ehanges in normal design eonditions are eommon over time, but even relatively stable applieations sueh as air separation are not totally immune from ehange. However, sinee die frequeney of ehanges in normal design eonditions for air separation plants is mueh less dian for namral gas proeessing plants, die following addresses turboexpanders in natural gas plant applieations. 

Liquid production is usually the main objective of any gas plant. Reductions in liquid production result in reductions in plant revenue. Revenue reduction is a major concern and is often what initiates a redesign project. 

New Mexico s San Juan Gas Plant is one of the United States newest and largest natural gas liquids recovery plant. Commissioned in November 1986, its levels of productivity are high by industry standards. Located near Bloomfield, New Mexico, just south of tlie Colorado border, the plant is jointly owned by Conoco Inc. (then a subsidiary of the DuPont Company) and Tenneco Inc., both of Houston. It is operated by Conoco and is named after its location in the San Juan basin, an area of oil, gas, and coal production. 

General. With simple instrumentation discussed here, it is not possible to satisfactorily control the temperature at both ends of a fractionation column. Therefore, the temperature is controlled either in the top or bottom section, depending upon which product specification is the most important. For refinery or gas plant distillation where extremely sharp cut points are probably not required, the temperature on the top of the column or the bottom is often controlled. For high purity operation, the temperature will possibly be controlled at an intermediate point in the column. The point where AT/AC is maximum is generally the best place to control temperature. Here, AT/AC is the rate of change of temperature with concentration of a key component. Control of temperature or vapor pressure is essentially the same. Manual set point adjustments are then made to hold the product at the other end of the column within a desired purity range. The technology does exist, however, to automatically control the purity of both products. 

Hydrogen attack at a. Ambient to boiling a. Numerous a. Gas plants, acidic a. Rimmed, capped, a. Diffusion of a. Eliminate water... 

Problem A gas plant absorber/deethanizer train was not achieving design separation. The absorber and the deethanizer seemed to be operating at poor efficiencies. 

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