Thermal expansion inside a valve caused the bonnet of the valve to fail. The safety alert mentions the following:
Pressure build-up occurs in the gate valve cavity from thermal expansion of fluids. Extreme pressure build-up from fluid expansion can occur if the valve body is completely full of fluids (e.g., a grease/oil/water mixture) and heated to elevated temperatures. Such pressure can exceed the rated working pressure of the valve.
A valve with the ability to isolate the body cavity from the flow line may be at risk.
Presence of grease or compounds designed to enhance sealing ability may exacerbate the condition.
Grease or a grease/oil/water mixture when heated in a sealed enclosure can exceed 7000 psi (48.5 MPa) at 250 °F (121 °C).
Gate valve body cavities that are not 100% full of fluids do not experience excessive pressure as the vessel was heated. Trapped air or gas allows room for thermal expansion.
Read the safety alert in this link.
Contribute to the surviving victims of Bhopal by buying my book "Practical Process Safety Management"
Pressure build-up occurs in the gate valve cavity from thermal expansion of fluids. Extreme pressure build-up from fluid expansion can occur if the valve body is completely full of fluids (e.g., a grease/oil/water mixture) and heated to elevated temperatures. Such pressure can exceed the rated working pressure of the valve.
A valve with the ability to isolate the body cavity from the flow line may be at risk.
Presence of grease or compounds designed to enhance sealing ability may exacerbate the condition.
Grease or a grease/oil/water mixture when heated in a sealed enclosure can exceed 7000 psi (48.5 MPa) at 250 °F (121 °C).
Gate valve body cavities that are not 100% full of fluids do not experience excessive pressure as the vessel was heated. Trapped air or gas allows room for thermal expansion.
Read the safety alert in this link.
Contribute to the surviving victims of Bhopal by buying my book "Practical Process Safety Management"
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