Hydrogen in the power industry

Abstract

UDC 546.11 According to climatologists, the troposphere is becoming steadily less stable. This is associated both with its loss of intrinsic stability and with superstabilization of the atmosphere, which is evident in the high stability of anticyclones. Overall, the climate is diverging from traditional patterns. These phenomena are accompanied by global warming, by 0.3-0.6 or 0.50.7~ (according to different estimates) from the industrial epoch (the late 1940s and early 1950s). By scientific consensus, this global warming is associated with a greenhouse effect due to the accumulation of greenhouse gases (CO 2, CH 4, N20 (NOx), 0 3, F, CI, hydrocarbons, etc.) in the atmosphere. Most (up to 75%) of the greenhouse effect is due to CO 2 released in technological processes; methane emission is the next most significant factor, and the other greenhouse agents, including tropospheric ozone, account for only a few percent. Worldwide technogenic CO 2 emission is around 7 Gton/year. In addition, with the felling of tropical rain forests and continuing contamination of the oceans, natural mechanisms for CO 2 absorption are becoming steadily less effective. Consequently, global warming may be expected to continue. Estimates by the Russian Institute of Atmospheric Physics [1] show the likelihood of increasing climatic instability with increase in the mean CO x content in the atmosphere. As an illustration, note the increase in the number of tornadoes each year in the United States between 1953 and 1991. The main sources of carbon dioxide include energy generation (thermal energy based on natural fuel), ground and air transport, metallurgy, the cement industry, the oil and gas industry, and the chemical industry. An obvious approach to reducing atmospheric pollution is to limit technogenic CO- 2 emissions. The most significant CO 2 sources are thermoelectric power plants and boilers that use coal, fuel oil (raw petroleum), and natural gas as fuel. For Russia, the breakdown of these fuels is, %: fuel oil and oil 11.5, coal 27.5, natural gas 61. In addition, around 25 % of CO 2 release in Russia comes from decentralized heating systems, which tend to shift the balance toward fuel oil and coal consumption. Thus, in Russia, more than 40% of thermoelectric sources consume coal and fuel oil. The overall trend in the period 1980-1996 is a relative increase in gas consumption (by a factor of about 2.3 over 15 years); this is natural, since around 40% of the world's known gas reserves are in Russia. The shift from fuel oil and coal to natural oil in Russia must reduce the carbon-dioxide emission due to heat generation, but this is offset by the deteriorating quality of Russian equipment and the deviation from optimal technological conditions. The dominance of natural fuel is found throughout the world, in both developed and developing countries. Ground and air transportation is characterized by a steadily increasing rate of CO 2 emission, primarily because of the growing number of vehicles using traditional hydrocarbon fuel. Note that, besides carbon dioxide, the main toxic materials released into the atmosphere by the transportation industry include carbon monoxide, NO x, CH x, solid carbon, and benz-otpyrene. The situation has grown much more serious in the last few years, especially for large cities, where transportation accounts for the bulk of toxic releases: for example, 87% for Moscow, 65% for St. Petersburg, and 50% for Nizhnii Novgorod. The basic pattern is the same in France, Japan, the United States, and other developed countries. Ferrous metallurgy is responsible for considerable CO 2 emission. In the last few years, such CO 2 discharges have declined in Russia, largely because of the reduction in metallurgical production. Without going into details, the total CO 2 emission from this source may be estimated at approximately 1 Gton/year. Solution of this problem entails the decarbonization of natural fuel -- in Russia, in particular, the decarbonization of natural gas. This calls for the conversion of methane and other hydrocarbon components of natural gas to produce large quantities of commercial hydrogen.