Kogan Creek Power Station is part of CS Energy’s coal-fired power plant fleet, located in Queensland, Australia. The plant is equipped with MPS255 coal mills/pulverisers.

EnFloTech became involved in the project to address several issues with the mills:

• Kogan Creek Power Station uses MPS 255 mills.
• The station has a history of combustion stability problems, including fouling events, open pass wall cracking, nose cracking, and fan stalling.
• The initial solution was to achieve a better balance of Primary Air (PA) and Pulverised Fuel (PF) to the burners.
• PF flow distribution to the burners deviated by up to 50%.
• Orifice valves were replaced with coal flow balancing devices on mill F.
• Despite aggressive settings on the balancing devices, PF pipes 1, 2, and 5 experienced high coal flow, while pipes 3 and 4 remained lean.

EnFloTech approached the Kogan Creek Power Station project by focusing on a critical aspect of milling: the interface where the pneumatic conveying medium (air) meets the material to be transported (ground biomass flakes). This interface is located at the port ring of a vertical mill.

Upon analysing the baseline port ring (PR), it was discovered that the vane angle and the venturi design of the PR combined to create an angled vector directed into the mill’s grinding zone.

A comprehensive numerical model of the mill was built using drawings, measurements, and scan data. A baseline analysis was conducted using Siemens’ STAR-CCM+ software. EnFloTech’s patented V5 port ring (PR) was then incorporated, and a numerical comparison was performed to design a commercial trial.

The EnFloTech V5 PR is engineered to ensure an even flow distribution around the periphery of the grinding zone.

Furthermore, the EnFloTech V5 PR ensures a vertical vector flow is introduced through the mill to eliminate any swirl, which can lead to the formation of recirculation flow and cause suspended particle phenomena.

The ultimate goal is to achieve an even distribution of primary air (PA) and pulverised fuel (PF) among the five pipes leading to the burners. The modular replacement of the baseline port ring with the EnFloTech V5 PR resulted in a numerical prediction of PA/PF distribution within the acceptable 10% deviation from the average. The numerical analysis confirms that the baseline distribution falls outside the acceptable threshold, which poses an increased risk for particle rich pipes that can lead to blockages.

The baseline port ring (PR) experienced significant wear and erosion, which the numerical study accurately predicted.

The loading frame is subjected to high-velocity pulverised coal, which is extremely abrasive and causes premature wear, risking its useful life and mechanical integrity. Combined with the limited ergonomic design, this presents a significant problem given the cost, lead time, and threat to the plant’s reliability.

• 11% reduction in mill dP
• No carbon (primary energy) in rejects after modification compared to fine unground coal lost due to rejecting before modification.
• Modular fitment – total duration 3×12 hour shifts

The loading frame is subjected to high-velocity pulverised coal, which is extremely abrasive and causes premature wear, risking its useful life and mechanical integrity. Combined with the limited ergonomic design, this presents a significant problem given the cost, lead time, and threat to Kogan Creek Power Station plant reliability.

• 28% reduction in mill dP (differential pressure)
• 34% reduction in mill ratio (mill classification has improved significantly which is resulting in fuel being processed through the mill at a faster rate, less recirculating load, faster mill response)
• 16% reduction in HA damper position when compared with other mills – noting +2kg/s PA flow on this mill
• 18% reduction in mill motor power (aux power savings)
• PF distribution within specifications – improved PF control – boiler flame stable

EnFloTech is now the proud OEM of the port rings at Kogan Creek Power Station. The station mills are now fully converted to EnFloTech’s technology.