OCR Text |
Show population and perhaps as much as 40% of the industrial activity. Intermediate 'limits apply to the heavily industrialized areas of Guadalajara, Monterrey, Salamanca, Minatitlan, Tampico, Tula and the US border, where a heavy concentration of maquilas exist. Efforts have been made by PEMEX to make natural gas and clean oils available in these areas. Natural gas is also being imported from the USA along the border. The least restrictive limits apply to the rest of the country. MEXICO.· EMISSION UMIT ZONES. Figure 3.1.- NOx limit Zones in Mexico Figure 3.2 shows an extract from NOM-PACCAT -019/93 for existing units. NOx AND CO UMITS FOR EXISTING UNITS MEXICAN OFFICIAL NORM NOM·PA-CCAT -019,'93 BOILER NITROGEN OXIDES 00 CAPN::nY TYPE~ ppnv • 5% 02, Dry ,,-M~ CUM B'TlMHr) FUEL MaEnXI'C O CZROITNICEASL CROEUSNTTR~Y AU. ZONES UQUIO 160 aJO 270 3.3 TO 40 aJO GAS 130 160 180 40 TO 10t LIQUID 140 180 250 160 GAS 120 140 180 MORE THAN UQUIO 130 160 230 10t GAS 100 130 160 100 Figure 3.2.- CCAT -019/93 for existing units. Figure 3.3 shows the limits applicable to new units, which are more restrictive than those for existing units. Although this law imposes lower Page 5 limits than the previous one, the NOx limits are still very relaxed by today's standards and can be comfortably met in most boilers firing natural gas with inexpensive approaches. Fuel oil firing is a different story, though. Although PEMEX is making efforts to supply "gasoil" (a blend of residual and distilled oils containing less than 0.1 % Nitrogen, less than 2% sulfur and less than 4% Conradson Carbon) to plants located in the so-called critical zones and currently firing residual oil, this cleaner fuel remains scarce and expenSlve. NOx AND CO UMITS FOR NEW UNITS MEXICAN OFFICIAL NORM NOM·PA-CCAT -019/93 BOILER NrTAOGEN OXIDES 00 CAPN:ATY TYPE~ ppnv • 5% 02, Dry PP"'f.6~ FUEL MEXICO CRmCAL REST~ CU" BT\.MHr) an' ZONES COUNTRY AU. ZONES UOUID 150 UP TO 10t 150 GAS 130 UORETHAN UOUID 100 140 aJO 104 100 GAS 75 100 130 Figure 3.3.- CCAT-019/93 NOx limits for new units. In addition to the above limits, all existing units subject to major repairs or retrofits involving an investment equal to at least 50% of the current reposition value of the unit must comply with the NOx limits applicable in Mexico City for the same capacity and fuel type, and be equipped with low NOx burners. In typical fashion, the law establishes a compliance period of 60 days from publication, which would have expired in June 1993, when many operators of stationary sources were only becoming aware of its existence. The reality is that enforcement of the law has been subj ect to the availability of inspectors and, as usual, to the discretionary powers of SEDESOL. |