OCR Text |
Show Future Trends The uncertainties of key variables make the quantitative prediction of future trends very difficult; however, several factors appear to indicate the need for more stringent N0X control capabilities in several areas. Some of these are discussed briefly. Coal use. The National Energy Plan calls for a significant increase in coal utilization by industrial and utility sources. The actual increase depends on (a) coal production capability, (b) energy consumption growth rate, (c) nuclear energy expansion rate, (d) economics, and (e) environmental regulations. A first step is that virtually all new utility boilers are coal fired. The result on N0X emissions from this source can be generally illustrated by the fact that the current NSPS for coal-fired utility boilers are 2.3 and 3.5 times those for oil- and gas-fired boilers,- respectively. With the 1971 NSPS for coal-fired utility boilers, one recent projection indicates that the increase in total N0X emissions from 1972 to 2000 would be from 30 to 80 percent dependent on the assumptions of energy growth and nuclear capacity. Progressively higher levels of emission controls through 1988 are required to significantly reduce the rate of increase. Therefore, major emphasis on emission controls for coal-fired industrial and utility boilers appears to be imperative. Alternate fuels. Significant effort is underway in the United States to develop and commercialize processes for producing alternative gaseous, liquid, or solid fuels from coal or shale. Although most of these processes significantly reduce two of the objectionable components (sulfur and mineral matter) associated with coal, they do not eliminate chemically bound nitrogen. Typically, liquid fuels derived from coal and shale have nitrogen contents from 0.5 to over 2.0 percent by weight. Although this nitrogen can be at least partially removed by hydrotreating, it is potentially an expensive and energy intensive process. Similarly, low and medium Btu fuel gas produced from coal has the potential for containing up to 4000 ppm NH3 and cleanup, particularly at high temperature, remains difficult. Evidence indicates that combustion modification should be equally or more effective for alternative fuels than for coal and heavy petroleum oil. Further development of the technology on the specific fuels is required. 3-Ll |