EDV wet scrubbing system

The EDV Wet Scrubbing System utilized proprietary nozzles to produce high-density water curtains through which the gas must pass. Each nozzle sprays water droplets that move in a cross-flow pattern relative to the flue gas. These cover the entire gas stream and uniformly flush the vessel s surfaces clean. The spray nozzles are nonclogging and are designed to handle highly concentrated slurries. 

In order to illustrate the typical performance of this system, the EDV system installed at a U.S. refinery is utilized. At this refinery, an EDV wet scrubbing system was installed to bring a new small RCC in compliance with New Source Performance Standards (NSPS) for particulate and SO2 emissions. 

From an operator s perspective, the scrubbing system required very little attention. Normally, the only attention required is a routine walk-by of the equipment to ensure that everything is in normal operation. Since 1998 the refinery took the RCC out of operation and moved the EDV Wet Scrubbing System over to their SRU and applied it as a tail gas cleaning device. The system is presently operating at very high efficiency as a tail gas unit to rave reviews of the refinery client. 

The LoTOx process represents a high-efficiency alternative to SCR. When combined with the EDV Wet Scrubbing System, LoTOx can provide similar or higher NOx reductions as an SCR, but without any of the associated concerns. 

The demonstration achieved all objectives and proved that the EDV Wet Scrubbing System with LoTO, technology can easily be applied to FCCU applications for reducing both the NOx and SO, together. The demonstration proved that even when used on an FCCU flue gas, the combination system can reduce SO2 greater than 99% and NO, greater than 90%. In addition, the EDV system s ability to reduce particulate emissions makes this a real all-pollutants reduction system. Figure 17.27 documents the results from the demonstration. 

Marathon proceeded to purchase and install LoTOx technology for application to their existing EDV wet scrubbing system at Texas City based upon the results of the technology demonstration. This system started commercial operation in February, 2007 [7]. The initial NOx reduction results from the commercial application have confirmed the results of the demonstration. Results from the first week of operation on the first LoTOx unit installed on an FCCU is shown in Figure 17.28. Subsequent testing has confirmed operation below 10 ppm. This outlet NOx is adjusted by varying the set point on the system controller. 

Because the Marathon application was a retrofit to an existing EDV wet scrubbing system, a separate tower had to be built to provide the ozone injection and the required reaction zone. Figure 17.29 shows the actual unit layout. Although this approach was a more expensive approach, it was still significantly more cost effective than an SCR system based upon Marathon s analysis. 

FIGURE 16.5 EDV 5000 model wet scrubbing system. (With permission from Belco... 

Several licensors currently offer FCC wet scrubbing technology. For the general purpose of this chapter, the discussion will focus on application of the Belco technology (BELCO, EDV, and L ABSORB are registered trademarks of Belco Technologies Corporation). This system has been described previously in literature [11]. 

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