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Wang Long Power, Guangzhou

LP Amina fulfils Guangzhou Wan Long Power’s Environmental ambitions

 

In recent years the Southeastern Pearl River Basin has been one of the two fastest growing regions of China. At the heart of the region lies the city of Guangzhou, formerly known as Canton, famous for its cuisine and its entrepreneurial, outward-looking people. It is thus not surprising that LP Amina’s second China success story in designing and constructing an improved power plant combustion system delivering over 60% reduction in nitrous oxide pollution (NOx) would occur in this progressive and dynamic region. Observing LP Amina’s previous combustion improvement/NOx pollution reduction successes at YiXing Union Cogeneration located in China’s other most dynamic region, the eastern coastal Yangtse River Basin, the Wang Long Power Plant awarded LP Amina with a contract to do a similar retrofit for Wang Long’s 100 MW Units 1 and 2. Numerous NOx retrofits have been performed in the United States, Europe and Japan, but this technology is still in its infancy in China. In addition to the typical motivation to reduce pollution from existing facilities, balancing the natural pollution increase resulting from the appearance of new factories, automobiles and other pollution sources, the Guangzhou local government asked local industry for particular help in reducing city pollution in advance of hosting the Asian Games athletic competition in the city in the Fall 2010.

 

Wanglong choose LP Amina over many other bidders for several reasons. LP Amina was able to guarantee that after retrofit, emissions would not exceed 250 mg/Nm3 of emissions, a lower level than all of the other bidders were able to meet. In addition, LP Amina guaranteed that the plant’s energy efficiency would be maintained or increased from pre-retrofit levels. In effect LP Amina’s efficiency guarantee meant that the retrofit would result in no additional operational costs for Wanglong, essentially delivering free pollution reduction, after accounting for Wanglong’s initial capital investment in the project. LP Amina’s use of foreign conceptual design and Chinese local detailed design and equipment supply allowed Wanglong to enjoy the most advanced retrofit technology at an affordable price.LP Amina has developed a unique design for separated over-fired air nozzles along the walls of the plant boiler, displacing the traditional corner location for NOx reducing over-fired air retrofits. As a result of this unique design, air is more uniformly and efficiently delivered to the combustion process. LP Amina’s advanced air distribution design means that the combustion gases form less NOx pollution and more of the fuel (in the case of Wang Long coal) is burned and converted into energy rather than passing through the boiler and being wasted.

 

The Wang Long NOx retrofit was successfully completed in September 2010. The success of the design strategy was seen at Wang Long by a reduction of above 60% in unburned carbon (UBC), an important indicator of energy efficiency and coal waste, while meeting contractually guaranteed levels of NOx emissions. Combustion-based NOx pollution reduction projects typically use over-fired air, a process which removes air from the lower boiler elevation, where the combustion occurs first, and increases air supply to the higher boiler elevation. This process lengthens the time available for fuel combustion while lowering combustion temperatures. Since much more NOx is formed at higher temperatures than lower temperatures NOx emissions are reduced. With traditional designs, lower NOx emissions often come at a price of loss to energy efficiency and this efficiency reduction is frequently seen in increases of UBC. In this light LP Amina’s above 60% reduction of UBC was among the main successes of the Wang Long NOx retrofit project.

 

Item Boiler Before Guarantee After
NOx #1 650mg/Nm3 250mg/Nm3 232mg/Nm3
#2 700mg/Nm3 250 mg/Nm3 241 mg/Nm3
UBC #1 4.5% 3% 1.71%
#2 4.1% 3% 1.48%
Boiler efficiency #1 91.90% 92.05% 92.32%
#2 91.95% 92.05% 92.81%
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