Gas continued natural

Natural gas continues to be the fuel of choice for power generation and feedstock for a range of petrochemical industries. This trend is driven by environmental, economic and supply considerations with a balance clearly tilting in favor of natiual gas as both fuel and feedstock. 

The Piper Alpha disaster in the North Sea in the mid-1980s, involving over 150 dead, was worsened when natural gas continued to flow from another gas platform to Piper Alpha (which was the jimction or collecting platform) because no-one told the other platform to cut the flow the emergency plans had apparently not included a multiplatform approach. 

Another area of my post-Nobel research that turned into a major continuing effort evolved from the realization that our hydrocarbon resources, the marvelous gift of nature in the form of petroleum oil and natural gas, are finite and not renewable. 

Coal is used ia industry both as a fuel and ia much lower volume as a source of chemicals. In this respect it is like petroleum and natural gas whose consumption also is heavily dominated by fuel use. Coal was once the principal feedstock for chemical production, but ia the 1950s it became more economical to obtain most industrial chemicals from petroleum and gas. Nevertheless, certain chemicals continue to be obtained from coal by traditional routes, and an interest in coal-based chemicals has been maintained in academic and industrial research laboratories. Much of the recent activity in coal conversion has been focused on production of synthetic fuels, but significant progress also has been made on use of coal as a chemical feedstock (see Coal CONVERSION processes). 

Trends in commercial fuel, eg, fossd fuel, hydroelectric power, nuclear power, production and consumption in the United States and in the Organization of Economic Cooperation and Development (OECD) countries, are shown in Tables 2 and 3. These trends indicate (6,13) (/) a significant resurgence in the production and use of coal throughout the U.S. economy (2) a continued decline in the domestic U.S. production of cmde oil and natural gas lea ding to increased imports of these hydrocarbons (qv) and (J) a continued trend of energy conservation, expressed in terms of energy consumed per... 

Renewable carbon resources is a misnomer the earth s carbon is in a perpetual state of flux. Carbon is not consumed such that it is no longer available in any form. Reversible and irreversible chemical reactions occur in such a manner that the carbon cycle makes all forms of carbon, including fossil resources, renewable. It is simply a matter of time that makes one carbon from more renewable than another. If it is presumed that replacement does in fact occur, natural processes eventually will replenish depleted petroleum or natural gas deposits in several million years. Eixed carbon-containing materials that renew themselves often enough to make them continuously available in large quantities are needed to maintain and supplement energy suppHes biomass is a principal source of such carbon. 

Substitute or synthetic natural gas (SNG) has been known for several centuries. When SNG was first discovered, natural gas was largely unknown as a fuel and was more a religious phenomenon (see Gas, NATURAL) (1). Coal (qv) was the first significant source of substitute natural gas and in the early stages of SNG production the product was more commonly known under variations of the name coal gas (2,3). Whereas coal continues to be a principal source of substitute natural gas (4) a more recendy recognized source is petroleum (qv) (5). 

The first gas producer making low heat-value gas was built in 1832. (The product was a combustible carbon monoxide—hydrogen mixture containing ca 50 vol % nitrogen). The open-hearth or Siemens-Martin process, built in 1861 for pig iron refining, increased low heat-value gas use (see Iron). The use of producer gas as a fuel for heating furnaces continued to increase until the turn of the century when natural gas began to supplant manufactured fuel gas (see Furnaces, fuel-fired). 

Confederation of Independent States (CIS) are denoted as explored reserves and include proved, probable, and some possible gas. The data for Canada also include some probable reserves. The worldwide natural gas reserves have continued to increase as the demand for gas has increased and exploration efforts have expanded. In 1976, the world natural gas reserves were estimated to be 6.58 x 10. In 1987, the reserves were 1.06 x lO ", and by 1992... 

Outlook. Since natural gas became a commodity of commerce and its potential as an energy form was recognized, its use on a worldwide basis has continued to increase. Adequate proven reserves have been developed and the necessary production and deflvery infrastmctures have been estabUshed... 

The high cost of coal handling and preparation and treatment of effluents, compounded by continuing low prices for cmde oil and natural gas, has precluded significant exploitation of coal as a feedstock for methanol. A small amount of methanol is made from coal in South Africa for local strategic reasons. Tennessee Eastman operates a 195,000-t/yr methanol plant in Tennessee based on the Texaco coal gasification process to make the methyl acetate intermediate for acetic anhydride production (15). 

The nameplate capacity of worldwide methanol plants is given by country in Table 2 (27). A significant portion of this capacity is based on natural gas feedstock. Percent utilization is expected to remain in the low 90s through the mid-1990s. A principal portion of this added capacity is expected to continue to come from offshore sources where natural gas, often associated with cmde oil production, is valued inexpensively. This has resulted in the emergence of a substantial international trade in methanol. In these cases, the cost of transportation is a relatively larger portion of the total cost of production than it is for domestic plants. 

If possible comparisons are focused on energy systems, nuclear power safety is also estimated to be superior to all electricity generation methods except for natural gas (30). Figure 3 is a plot of that comparison in terms of estimated total deaths to workers and the pubHc and includes deaths associated with secondary processes in the entire fuel cycle. The poorer safety record of the alternatives to nuclear power can be attributed to fataUties in transportation, where comparatively enormous amounts of fossil fuel transport are involved. Continuous or daily refueling of fossil fuel plants is required as compared to refueling a nuclear plant from a few tmckloads only once over a period of one to two years. This disadvantage appHes to solar and wind as well because of the necessary assumption that their backup power in periods of no or Httie wind or sun is from fossil-fuel generation. Now death or serious injury has resulted from radiation exposure from commercial nuclear power plants in the United States (31). 

Until 1960—1970, in countries where natural gas was not available, large amounts of coal were carbonized for the production of town gas, as well as a grade of coke which, although unsuitable for metallurgical use, was satisfactory as a domestic fuel in closed stoves. The early cast-iron and siUca horizontal retorts used at gasworks were replaced by continuous vertical retorts. These operated at flue temperatures of 1000—1100°C. The volatile products were rapidly swept from the retort by the introduction of steam at 10—20% by weight of the coal carbonized. 

Conventional Sintering Equipment. Like drying furnaces, sintering furnaces (29,76,85) can be periodic or continuous in nature. Periodic kilns offer greater flexibiHty continuous tunnel kilns are more economical. Advanced ceramics are typically siatered in high purity, controUed atmosphere furnaces by electric resistance heating. Ceramic furnaces used to fire traditional ceramic ware are generally heated with inexpensive natural gas, oil, wood, or coal. 

Chlorination of Methane. Methane can be chlorinated thermally, photochemicaHy, or catalyticaHy. Thermal chlorination, the most difficult method, may be carried out in the absence of light or catalysts. It is a free-radical chain reaction limited by the presence of oxygen and other free-radical inhibitors. The first step in the reaction is the thermal dissociation of the chlorine molecules for which the activation energy is about 84 kj/mol (20 kcal/mol), which is 33 kJ (8 kcal) higher than for catalytic chlorination. This dissociation occurs sufficiendy rapidly in the 400 to 500°C temperature range. The chlorine atoms react with methane to form hydrogen chloride and a methyl radical. The methyl radical in turn reacts with a chlorine molecule to form methyl chloride and another chlorine atom that can continue the reaction. The methane raw material may be natural gas, coke oven gas, or gas from petroleum refining. 

The economics of coal gasification are influenced by the availabiHty of oil and natural gas, but coal is expected to continue to play an ever-increasing role as a significant resource base for both energy and chemicals. 

Batch (or beU) annealing is done within a sealed inner retort that contains a protective atmosphere. Burning natural gas is contained between the latter and an external retort. Continuous (strand or strip) annealing uses a furnace sealed at both ends to contain a protective atmosphere while permitting passage of the strip. Strand annealing is normally carried out at strip thicknesses from 0.25 mm (0.010 in.) to 3.18 mm (0.125 in.). 

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