OCR Text |
Show oils are all other oils. Gaseous (uels other than Natural Gas are not subject to NSPS. By today standards, NOx limits set by the NSPS are quite relaxed and can be comfortably met with economical approaches to NOx reduction. In some cases NOx reductions are not even required to meet them. These limits are the result of a long negotiation process among EPA, industry leaders, environmentalists and other organizations since the NSPS was originally proposed in 1984. Given the fact that NSPS established different NOx limits for different fuels, it was not meant to promote fuel substitution as a NOx reduction measure. A "Small Boiler NSPS" was promulgated on September 1990, which applies to new, modified and reconstructed small industrial, commercial and institutional boilers with design heat releases from 1 0 to 1 00 million BTUlHr. Although this law sets S02 and Particulate matter limits, it does not include NOx standards. No federal NOx standards for small boilers have been promulgated and may never be promulgated now that states are taking a more aggressive role in limiting emissions. State and IAcal Regulations.- California SCAQMD Rules. Among the countless local regulations, the SCAQMD has been a leading force in the USA, and perhaps the world, with the promulgation of a series of "Rules" aimed at reversing the trend on air pollution in one of the most economically active areas of the USA: the Los Angeles Basin. SCAQMD includes the counties of San Bernardino, Los Angeles, Orange and Riverside, in southern California. Rule 1109.- Emission of Oxides of Nitrogen from Boilers and Process Heaters in Petroleum Refineries. Adopted on November 1985 and amended on August 1988, this regulation introduced some Page 2 interesting concepts. One is the concept of phased limits by which the law itself establishes ever lower NOx limits that will come into effect on predefined dates. This was meant to allow refineries to better plan investments required for compliance with the law. During the first stage, the limits were not only more relaxed, but compliance was required not for individual units but for the whole plant under the so called "bubble" concept. In a second stage the limits were significantly lower and individual unit compliance was required but only for a portion of the units in the refinery, to be chosen by the owner, up to 36% of total plant heat input. During the third stage to begin Dec. 31, 1995, all emission sources in a refinery have to comply with the lowest NOx limits, regardless of their rated capacity. This rule was also one of the first to include limits that promoted fuel substitution. The same limits apply independently of the fuel being fired. Most fuel oils were implicitly prohibited since the limits set could not be met firing oil with any of the technologies currently available. Presently, only Natural Gas and the so called "Lo-NOx" light oils (with extremely low fuel bound nitrogen contents) can be fired to meet Rule 1109 in an economically feasible manner. Figure 2.2 shows a summary of Rule 1109. The limits are set in IblMM BTU, approximate PPM converSions are provided for comparison purposes only. Rule 1146.- Emission of Oxides of Nitrogen from IndustJial, Institutional and Commercial Boilers, Steam Generators and Process Heaters. Adopted on September 1988 and amended on January 1989, this rule required NOx reductions for most boilers and process heaters. It established NOx limits of 40 PPM for units with rated heat input capacities between 5 and 40 million BTUlHr, and 30 PPM for units rated at or above 40 million BTUlHr. Similar to what Rule 1109 did for refineries, this rule effectively bans the use of most fuel oils on industrial, institutional and commercial boilers. In practice, • |