Wear Protection
System enables power plant waste ash to be sold L
eading UK wear protection specialist, Kingfisher Industrial, has been appointment as exclusive agent
for the patented milling and combustion enhancement technologies of USA- based SAS Global. The SAS technology offers both environmental and commercial benefits for coal-fired plant operators, enabling ash to be sold rather than sent to landfill. SAS technology provides an efficient
solution under today’s demanding operation conditions, when both plant efficiency and environmental compliance are two of the main issues facing generators. It quickly achieves the performance benefits required to offset its initial capital cost. The technology improves both the output volume of fuel to power station boilers and the compliant grade with regard to particle size, thus reducing loss of ignition within the boiler (LOI). It also improves distribution of fuel/ air ratios at the classifier outlet, resulting in reduced NOX
emissions, improved
combustion and a reduction in carbon in ash contamination. Due to the design of the rotating vane wheel, high spin classifiers blades and feed cone extension equipment, these enhancements deliver efficiency
As regards improved distribution of fuel,
SAS’s patented ‘Ropebreakers’ (Multi-outlet, Pre-riffle & Burner In-line diffusers) ensure correct air/fuel ratios are achieved. The ‘Ropebreaker’ systems diffuse the
‘roping’ effect of fuel prior to splitters, thus ensuring a greater degree of balance is achieved in the pulverised fuel (PF) pipework after the splitting device. This process can be fine tuned with the use of patented in-line adjustable orifices, which counter the air imbalances caused by variable velocities associated to the different lengths of PF legs feeding burners in different positions on the boiler wall. The greater overall efficiency delivered
by SAS systems results not only in substantial operational cost savings, but also key environmental benefits due to the reduction in emissions achieved. The improvement in fuel to energy
Fig. 1. Ash from coal fired power stations becomes a useable resource thanks to SAS diffusion technology
improvements resulting in the mill being able to process a greater volume of fuel utilising the same amount of amps used to drive the rotating equipment.
(calorific value – CV) ratio results in a reduction of carbon in ash content, and this allows the ash to be sold as opposed to being sent for disposal and subject to hefty landfill tax levies. ●
For more information, visit
www.kingfisher-industrial.com
Corrosion-resistant heat exchangers A
lWaFlon pressure tubes supplied by Wallstein Ingenieur GmbH of Recklinghausen/Germany are made
with DuPont Teflon polytetrafluoroethylene (PTFE). This enables them to resist even the highly corrosive media present at flue gas desulphurisation plants of coal-fired power stations. Unlike heat exchangers made of nickel-
base alloys, these systems withstand a long- term exposure to aggressive acid mixtures. Such mixtures are comprised of SO2
, SO3 ,
HF and HCl, which are formed as flue gases cool and then condense on the heat exchanger surfaces along with ash particles. One current example is the heat displacement system employed at the hard coal-fired power plant at Siekierki near Warsaw, Poland. Here the energy recovered is used as a substitute for primary energy in reheating the cleaned flue gas. One benefit of this technology is that it prevents
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corrosion in the ducting and flue gas stack while also avoiding droplet formation once the gas is discharged from the stack. The system has been continuously in use for two years with no corrosion issues. Heat exchangers incorporating
AlWaFlon pressure tubes contribute significantly to the sustainable operation of coal-fired power plants. They are suitable for service in temperature ranges in which metal-based heat exchanger systems can no longer be used due to attack by a mixture of acids. As a result, fossil fuel input and emissions can be reduced even in
CO2
highly corrosive applications. Moreover, more efficient cleaning cycles can be implemented thanks to the anti-stick properties of Teflon fluoropolymers. An on-line cleaning system is also in use at the Siekierki plant. The CHP (combined heat and power)
generating station at Siekierki has a rated output of 620MW and is operated by PGNiG S.A. It comprises two flue gas desulphurization lines, including a heat displacement system, fitted by RAFAKO SA, the Polish equipment building company. The systems were sourced from
Wallstein and comprise 12 flue gas heat exchanger modules featuring AlWaFlon pressure tubes plus 42 clean gas heat exchanger modules of which 14 likewise incorporate AlWaFlon pressure tubes. Line 2 has been in service since November 2010; Line 1 was commissioned half a year later. Each of these lines saves 23MW of energy that would otherwise have to be sourced from superheated steam. This is
equivalent to an 8600kg/h reduction in CO2 emissions. ●
For more information, visit
www.dupont.com
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