Japan: Taiheiyo Cement has revealed that a weakness in an evaporator tube in a fluidised bed heat exchanger in a captive power plant was the cause of an explosion that took place at its Hidaka cement plant in April 2021. It said that inspections had been carried out annually but that it was difficult to detect defects visually. The company has apologised for the incident. It says it will make changes including a review of inspection standards, including more personnel in the process, improved information sharing and starting regular training on the issue. These changes will be implemented across all of the company’s plants.
The 50,000kW circulating fluidised bed (CFB) boiler was supplied by Mitsubishi Heavy Industries and commissioned in 1996. It ran on coal, wood chips and refuse-derived fuel. No blame for the explosion has been attributed to the manufacturer.
The explosion took place in the evening of 27 April 2021. No major injuries were sustained. However, 40 vehicles parked outside a Pachinko gambling parlour near the plant were damaged. Scattered debris was noted nearby and ash was reported up to 5km from the cement plant.