The (2) Siemens V 84.3A gas turbine project is rated 170 MW electric per gas turbine. The process and instrumentation diagram (P&ID) of the SINOx exhaust gas cleaning system is shown in Fig. 27. The SCR system design is based on the exhaust gas data listed in Figs. 28a and Fig. 28b. The system ensures State of Connecticut EPA compliance with the emission reduction of 91% to 4.5 ppmvd at 15% O2, dry basis for nitrogen oxides (NOx, as NO2).
The SINOx (SCR) system features the use of either aqueous urea or aqueous ammonia as the reducing agent to meet future, more restricted safety regulations. The SINOx system was delivered as two preassembled units.
FIG. 27 P&ID of a (2) gas turbine power generation plant.
A brief technical description of the systems function is provided in Fig. 29 and a system maintenance schedule is given in Fig. 30.
Mobile, Portable and Other Applications
Background Summary
California ARB (Air Resources Board) Strategy for Additional Emission Reductions by 2007/2010. During the University of California–Irvine Tech- nology Meeting on October 6, 1999, the Cal.-ARB presented its objectives to sub- stantially reduce NOx, HC, and PM emissions. To achieve California SIP (U.S.
EPA’s State Implementation Plan) goals by the year 2007/2010 emission of on- road and off/nonroad vehicles and equipment could be reduced by market incentive and monetary incentive programs. Retrofit emission reduction applications for die- sel locomotives, diesel-powered coastal vessels and construction/mining equip- ment, portable generation sets, and various agriculture (i.e., irrigation/pump drives) and garden equipment should be prime targets.
Summary of Recent Market Data on Retrofit Emission Reduction Target Markets. Over 50% of the total U.S. NOxemission inventory of ⬃25 million
tons per year and close to 60% of PM emissions is generated by portable, on-road, and off-road vehicles and equipment.
(a)
(b)
FIG. 29 Brief description of the SINOx system process.
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A total of 2.2 million tons/year of NOxfrom the United States representing8.6% were assumed from Class 8 HD diesel trucks. However, due to excess ‘‘off-test-cycle’’ emissions of 15.758 million tons during 1988 through 1998, caused by 1.328 million Class 8 trucks, an additional 1.3 million tons of NOx
FIG. 30 System maintenance schedule.
sent decree. This increased HDD truck NOxemission resulted in over 3.5 mil-
lion tons of NOxemission per year, equal to 12% of the total U.S. NOxinven-
tory.
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The Consent Decree of the U.S. Justice Department and the U.S. EPA, the State of New York, and Cal.-ARB with the engine manufacturers did not incorporate any short-term remedies but only engine-rebuilt solutions for this large fleet of highly fuel-efficient HDD trucks. One reason, according to industry, is the unrealistic U.S. FTP (Federal Transient Protocol) test cycle with heavy empha- sis on low torque/low rpm and high rpm, whereas most truck operations takeFIG. 31 Product summary, SINOx SCR System. (From Intermacom AG, Feb. 20, 2000, Draft for the WebPages of Cal.ARB.)
place in medium torque/rpm. In comparison, Japanese and European tests cycles emphasize medium torque/rpm, almost neglecting the low torque/low rpm oper- ation. One of these European tests shall now complement the U.S. EPA FTP tests. New trucks however, are required to meet NOx⫹ HC emission levels of
2.4 gr./BHP h by 2002/2004.
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Off-road NOxand PM emission from diesel-powered locomotives, ships, con-struction, mining, and agriculture equipment as well as portable equipment such as generation sets have not been a U.S. EPA priority even though they account for approximately one-quarter of the total U.S. NOxinventory. By 2010, U.S.
diesel locomotives are required to meet 5.6 gr./BHP h. California has an earlier target date and fleet averaging provisions. Also, marine applications lag behind, even though less than 2 gr./BHP h NOxemission rates have been demonstrated
in close to 100 marine diesel engine applications (with engines rated 300 to over 10,000 BHP) in Europe. Portable generation sets are not required to achieve better than 5.9 gr./BHP h NOxemission rates in California, whereas
some of the same engines in trucks have to meet 2 gr./BHP hr NOxin 2002/
2004. According to Cal.-ARB there are 72,064 portable and stationary diesel engines without emission controls in California, rated 110–600 BHP.
Reports on Technology Evaluations. In recent publications of UC-Davis’ ITS (University of California, Institute for Transportation Studies) and Diesel Fuel News, various emission control strategies for HD diesel engines were discussed. Two most promising retrofit technologies were identified achieving over 70–80% NOxand VOC/HC and substantial PM emission reduction: The UREA–SCR and
the NOxAbsorber Technology. All other retrofit/post treatment technologies are
either years away from any commercialization or achieve only 20–40% NOxreduc-
tion rates.
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The NOxAbsorber Technology has been tested by Cummins, using the Euro-3(13 Mode) Steady State Diesel Engine Tests and 5 ppm sulfur fuel, achieving 80% NOxreduction at a 8.5% fuel penalty. In a Marathon–Ashland Petroleum
commentary to U.S. EPA, it is claimed that only a 20,000-mile service life with 5–15 ppm sulfur fuel could be expected. Currently, no 15 ppm sulfur fuel is commercially available on a large-scale basis in the United States. The U.S. EPA does expect that such 15 ppm sulfur fuel will be readily available in the United States prior to 2007. In addition, lube oils with phosphor and sulfur com- pounds have to be reformulated and tested to avoid loss in engine service life.
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The UREA SCR Technology for the simultaneous reduction of NOx(70–85%),VOC/HC/AirToxics (80–95%), and PM (up to 50%) has already been used in HDD truck field tests in Europe and the United States in the 1990s. The technol- ogy will be commercially available by 2001, has been field tested for 4 years, and demonstrate no fuel penalty. The service life is expected to be over 300,000 miles and the initial target price is estimated to be US$ 2000–3000 per HDD truck. The European truck manufacturers and Siemens pioneered this technol- ogy. By the end of 2001, Siemens will go into the SCR system production for Daimler–Chrysler and MAN’s new ultralow-emission HD diesel trucks. The volume-produced SINOx Systems can then be used for mobile, transportable,
(a)
(b)
FIG. 32 (a) Stationary and mobile applications for the diesel SCR catalyst. (b) Simultaneous reduction of NOx, VOC/HC, and PM at stationary and mobile applications. (Courtesy of Siemens.)
and stationary engines rated 100–600 BHP. However, to use the prefabricated, off-the-shelf SINOx products as retrofits kits, engine model/application adapta- tions through local factory trained and licensed dealers are required.
The SINOx SCR systems are used in coal and gas-fired utility boilers and gas turbines, stationary and portable generation sets, cogeneration, and various mobile, on-road and off/nonroad applications. Figure 32 shows the range of SINOx Appli- cations.