Slide valves

<p>2010 Corbett  Black carbon - cost-effective emission reduction technologies</p>

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Slide valves replace conventional fuel valves, facilitating

more complete combustion at lower peak-flame temperatures

and thus reducing NOx and PM [37]. Slide valves

are reported to reduce PM emissions by approximately

25% [38,39], although estimates of 50% PM control have

been presented [40]. BC control performance estimates

have not been reported; we assume that slide valves will

reduce PM and BC similarly. Slide valves are already

in use in a good portion of the shipping fleet, as new

engines manufactured by MAN B&W (an engine technology

company that represents a large share of installed

power in the shipping market) come equipped with slide

valves. Table 3 presents technology-specific input ranges

for slide valves.

Cost estimates for the MAN B&W slide valves were

obtained from Entec [37]. These costs include: incremental

costs above conventional valves; installation costs;

and retrofit design and installation expenditures for

vessels older than 15 years [37].

Some researchers have suggested that there are no

O&M costs associated with slide valves, and, in fact

there may be benefits such as reduced fuel oil consumption

for lubrication [37], and fuel economy improvements

may result in low- and mid-speed engines. However,

slide valves can be associated with a fuel penalty of up to

2% when low-NOx behaviors are employed [38]. Other

slide valve performance attributes are defined to include:

ƒƒ CO2: fuel economy improvements will decrease CO2

emissions, while fuel penalties will increase CO2

emissions (range: -1 to 1%);

ƒƒ OC: slide valve impacts on OC are unknown; we

assume OC control is equal to PM control;

ƒƒ SO2/sulfates: slide valves have no known impacts on

SO2 or sulfates.</p>