Gaoqiao Petrochemical Co., Ltd. has made some achievements in the research on the causes of large oil and gas pipeline leakage, and the "Research on the influence of medium temperature change on the sealing performance of stainless steel flange joint" has been identified by a third-party expert group recently. After the research results are applied to the production of enterprises, the sealing performance of high-temperature equipment and pipeline bolt flange joints can be greatly improved, the hidden danger of sealing leakage can be effectively eliminated, and the operation safety factor of the device can be improved.
Due to the complex and diverse use environment and operation conditions, the leakage of bolted flange connection has become one of the most common accidents in petrochemical equipment, and the medium temperature change often leads to the sealing failure of the connection system, which has affected the production safety of the enterprise.
In order to improve the sealing performance and reliability of bolted flange joint, Gaoqiao Petrochemical, East China University of science and technology and Suzhou Baohua Machinery Technology Co., Ltd. jointly participated in the research on the influence of medium temperature change on the sealing performance of stainless steel flange joint, and studied and analyzed the causes of high temperature equipment and large oil and gas pipeline leakage according to the actual situation of the enterprise, and actively sought solutions.
The researchers use the intelligent detection system to detect the compression resilience, sealing performance and creep relaxation performance of flexible graphite metal spiral wound gasket and flexible graphite metal gasket under different temperatures; use the high temperature flange connection sealing performance detection device to measure the temperature change of each component of flange connection under different heating and cooling rates; use ANSYS The finite element software is used to simulate and analyze, and the curves of some key points on the bolt flange joint elements of the test device changing with the medium temperature are obtained. The thermal analysis models of flange joints with different pressure levels and specifications are established, and the transient and steady temperature fields of the above joints are analyzed. On this basis, the pre tightening state, operation condition and temperature rise of bolt flange connections are calculated The stress state and sealing performance of gasket under working condition; the failure mechanism of bolted flange connection sealing in the process of temperature rise and temperature drop was proved, and the cooling rate of flange connection leakage with different pressure levels and specifications was analyzed.
Based on the above results and combined with the actual needs of the enterprise, the researchers selected a batch of high-performance gaskets designed and processed by Suzhou Baohua Sealing Technology Co., Ltd., which were successively applied to two sets of large oil and gas pipelines and gas oil return system of delayed coking unit in 2014 and achieved success. Up to now, they have been in use for one year, with good sealing effect, no major leakage and emergency shutdown The treatment of leakage points greatly reduces the unplanned shutdown of the device caused by flange leakage, greatly saves the shutdown and maintenance costs caused by equipment and pipeline leakage in the past, and reduces the risk of environmental pollution.
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