COAL BLENDING AND THE INFINITY SERIES

 

 

BACKGROUND

Many coal fired power plants rely on one or two sources of coal, limiting the opportunity to blend their coal supplies. However to be competitive in today’s market, profit conscientious plant operators are  purchasing coal from multiple sources that usually vary in Btu quality and constituents such as sulfur, mercury, ash and moisture,.   To take advantage of the various lower cost coals it is necessary to blend the various stocks to obtain a preferred blend.  The typical method is to push the piles together with heavy material moving equipment.  This is a very inconsistent and labor intense method for blending coal.    Once the coal stocks are blended using this method you are left with an inconsistently blended coal supply.  To improve or modify the blend one must continue to add more coal to the mix and continue to push and hope. 

 

 

OPPORTUNITY – A REAL-LIFE EXAMPLE

An 1,800 Megawatt power station in Western Pennsylvania burns approximately 15,000 tons of coal per day. The power station was designed to burn coal having a heat value of 12,200 Btu’s.

 

Initially that coal was produced from an onsite mine. When the mine was no longer economically productive, the plant operators began using coal delivered by rail.  But the rail coal had a heat value of roughly 13,200 Btu’s, so the power station essentially was paying a premium for its coal supply.

 

To reduce its fuel costs, the power station contracted with local mines for coal of a lesser Btu value.  This coal was delivered by truck to be blended with the higher-quality rail coal. The lesser quality truck coal came from many different sources and the quality varied.   The truck loads were randomly dumped on a large pile and a very inefficient blending process was performed using bull-dozers. Not only was this inefficient, it also created safety and environmental issues.

 

Faced with the need to combine multiple coal supplies quickly and efficiently, the plant owners engaged GTC to design and construct a receiving and blending facility for the coal supplies that were delivered by truck to the plant.

 

 

THE INFINITY SERIES 1200 PROJECT DEVELOPMENT AND BENEFITS

We designed a coal receiving and blending facility to meet the power plant’s specific requirements for cost, efficiency and quality.  The end product was the Infinity Series 1200, designed specifically to accommodate a throughput of up to 1,200 tons of coal per hour to the power plant.  The innovative Infinity Series 1200 segregates, stores, reclaims and blends diverse fuel stocks consistently and accurately to the power plant’s desired specifications.

 

The Infinity Series 1200 is designed to maintain the integrity of the blend related to tons per hour (TPH) or to the quantitative results of an online analyzer.   The Infinity Series 1200 further provides for instantaneous adjustments to the fuels blend thus providing consistent quality.  Additionally, the blend parameters can be altered to respond to plant demand due to weather, power usage, and coal quality.  

 

 

CAPABILITIES

The patented Infinity Series 1200 employs a proprietary software program that controls and regulates all aspects of the operating system.  The software,  combined with strategically placed PLCs (Programmable Logic Controllers), allows for smooth and consistent operation  of,  but not limited to:  belt scales, weigh feeders, vibratory feeders, diverters, variable-frequency drives, conveyors, pile activators, slide gates, hopper vibrators, air cannons, crushers, fugitive dust control devices, telemetry devices, analyzers, surge bins and all other electro-mechanical material handling devices and controllers.

 

 

IMPLEMENTATION

Once designs were approved and permitting was completed, construction of the Infinity Series 1200 facility began in January 2010.  It was fully operational in December 2011.

 

 

OPERATION

The coal now delivered to the Infinity Series 1200 blending facility by truck is weighed and sampled before being deposited into drive-over hoppers. The hoppers are designated for various qualities of coal and allow for the segregation and/or pre-blending of the coal based on its quality, its sulfur, mercury, moisture and ash characteristics, or any other specific criteria.

 

The segregated or pre-blended fuel is then transferred by conveyors to the top of a series of stacking tubes that are linked by transfer conveyors. At the top of each stacking tube is a diverter valve.  The coal either drops down a chute that leads into the first stacking tube, or it continues on the conveyor system until it reaches the appropriate tube.

 

A series of openings on each side of the stacking tubes allows coal to flow out in a controlled fashion and form a conical pile around the base of the tubes. In this way, the tubes help to reduce the generation of coal dust, a major concern regarding air quality.

 

The stacking tubes are positioned above a reclaim tunnel that houses a conveyor belt that delivers the blended coal to the power station. The coal that collects at the base of the tubes enters one of several openings in the roof of a below-ground tunnel.

 

Openings in the tunnel roof are connected to an automated feeder system that directs a controlled volume of coal onto the conveyor belt within the tunnel. The computer-controlled feeder system includes a series of slide gates, feeders, and belt scales that is specially designed to enable precise blending of the various coals.

 

RESULTS

The existing Infinity Series 1200 now enables power plant operators to “dial up” a specific blend of fuel that produces optimum burn characteristics with lower cost coals, and with options for controlling emissions and ash quality. 

 

The system has been in continuous operation for several years, and it has received and delivered more than 9 million tons of accurately blended, economical and environmentally safe coal for power generation.

 

APPLICATION

The Infinity Series1200 is expandable and adaptable to any situation where receiving, staging, blending and delivery of coal fuel stocks in a safe, consistent, accurate and environmentally friendly method is required and expected.

 

 

OUR INVOLVEMENT IN YOUR PROJECT

Our staff and management will work with your organization in any of a variety of capacities to help ensure a successful completion of your project, including acting as consultants, project managers or general contractors.