| OCR Text |
3 CO. 2 _5 3 O r n a oi 10 12 Gas Cofire, % Figure 10. Purdue Particulate Emissions at 190-kpph Load. Figure 11 shows the effect of cofire on N O x emission from the Purdue boiler. The data show that, at 180 kpph load, N O x emissions were reduced about 6 percent with 10 percent cofire, a reduction consistent with the displacement of coal fuel with gas. However, in tests at 160 kpph load, performed with better management of overall boiler excess air levels, 11 percent N O x reduction at 10 percent cofire were achieved. NOx reductions were 22 percent at 20 percent cofire. These reductions are greater than what would result from displacement alone and indicate that, with proper burner operation, reduction of coal flame N O x via reburning can occur. Figure 12 shows the effect of cofire on CO emissions from the Purdue boiler. The figure shows that cofire promoted quite effective C O burnout, particularly at 190 kpph load. At this load, C O emissions were reduced to less than 200 p p m at 3 percent 0 2 from 300 p p m in one test and from 700 p p m in a test more in keeping with past Purdue experience. Morton International Morton International, Inc., produces salt and specialty chemicals at its Manistee, Michigan, plant. In the salt production process, salt (sodium chloride) is dissolved from underground deposits into water, producing a brine that is pumped to the plant and processed in evaporators to produce the salt product. A single coal-fired stoker boiler at the plant provides the process steam for these operations, as well as for mechanical drives in the powerhouse, for electricity cogeneration, and for space heat. Particulate emissions from the Morton unit are controlled by a multiclone mechanical collector. However, the need for further opacity control at the base boiler load required at the plant caused Morton to install and operate a flue gas recirculation (FGR) system driven by a 75-hp fan. The power requirements of this system, coupled with its high maintenance requirements and troublesome operating characteristics, led Morton the search for an alternative means of opacity control. 12 |
