Long Distance Pumping for Fly Ash Transfer
The customer is a part of about US $ 12 billion value Group. As a leading player in Steel, Power, Mining, Coal to Liquid, Oil & Gas and Infrastructure, they consistently tap into new opportunities by increasing production capacity, diversifying investments and leveraging its core capabilities to venture into new businesses. An enterprising spirit and ability to discern future trends have been the driving force behind the company's remarkable growth. To assist towards that effort, ABEL saw an opportunity to help with our model HMQ slurry pump.
|ABEL HMQ pump installed and running with 115 m³/hr (~160 GPM) at 25 bar pressure with ash slurry of 65% concentration being disposed to an ash dyke 7.5 km away.
Power Generation can be a dirty business. But with environmental protection as a priority, the client had to design a best available technology system to handle disposal of the ash produced by burning tons of coal for the captive power plant of capacity 358MW.
Also, the grade of coal used for power generation by this plant is "F" which ranks amongst the poorest grades having an average of 60% ash content.
This, added to thefact that they had already used up most of the ash dyke area around the plant (due to using the lean slurry technology earlier) made the task for ABEL and the system supplier all the more difficult and challenging.
|Ash slurry with 65% concentration being sent to the ash dyke 7.5 km away – with such little water content the dry ash solidifies in 3 to 5 hours.
The proposed system involved pumping high concentrate fly ash slurry around the perimeter of the ash dyke (evaporation pond) and allowing the slurry to dewater and form a solid outer barrier, increasing capacity to accommodate more slurry to be contained in the middle. This development necessitated the pumping of high concentrate fly ash slurry, of approximately 65% solids content, through a 7km long pipeline to the ash dyke.
The challenge was to find a reliable pump & system that could not only handle the flow and high pressure requirement, but also endure high abrasion while limiting costly downtime and maintenance.
Down time in an ash disposal section of a power plant directly translates to loss of revenue as the ash generation rate needs to be reduced and this is only possible witha reduction in the coal firing rate. This in effect means a reduction in the MW generation of the plant.
The ABEL Solution
ABEL, in association with the ash handling system supplier, Macawber Beekay, proposed a solution wherein the ash generated would be mixed with water in a 65:35 ratio and this slurry would be transported to the ash dyke about 7 to 8 kms away. Each unit today has 2 ABEL mODEL HMQ-1000 diaphragm pumps which are fitted into the HCSD (High concentrate Slurry Disposal) system designed and executed by Macawber Beekay Ltd. – a leading ash handling systems vendor in India.
The ABEL Hydraulic Diaphragm pump series (HMQ) is a Piston-Diaphragm type, designed with a hydraulic section which separates the slurry from the drive piston and isolates wear to the inexpensive elastomer components, i.e. diaphragms, check cone valves and seats. 4 of these pumps are now running at this steel plant since Jan 2010. Each of these has an independent 7 to 8 km discharge pipeline to the ash pond.
Aerial view of the plant.
Records from these plants show that the ABEL pumps are operating at nearly 66% concentration (66 % ash and 34 % water). With these concentrations, the achieved flow rate is 115 m3/hr and pressures reached are about 25 bar. Owing to superior design and impeccable manufacturing standards adopted at ABEL, even under these strenuous conditions, the ABEL pumps have constantly performed at their peak and we are proud to state that the power generation unit of the plant has always generated its rated output.