Preparations before gas holder replacement (II)

Replacement process flow
(1) In order to facilitate command and control and avoid operation errors, before replacement, all valves shall be closed and blind plates shall be installed to make the whole system in a sealed state.
(2) Open the control valve of the air inlet pipe, fill the gas tank with compressed air, slowly increase the pressure to 2000Pa, maintain the pressure for 10 minutes, and observe the pressure change of the gas tank. If there is no pressure drop, the seal is good.
(3) Replace after passing the pressure test. First, open the valve of the gas filling pipe or the vent valve to vent, and close the valves of each vent position until it is balanced with the atmospheric pressure. At this time, the volume of air covered by the arc top in the gas holder is about 1700m3 under the calculation condition.
(4) Open the valve on the inlet pipe of the gas tank, fill the gas tank directly with natural gas, control the flow rate below 3m/s, and open the vent valve and sampling port around the gas tank. Use a methane detector to monitor at the sampling port. When the methane content at any sampling port is more than 2%, close the vent valve immediately. When the gas tank rises 0.7m from the initial position, the inflation speed can be appropriately increased, and the flow rate shall not exceed 5m/s; When the gas tank rises to 1.2m, the air inlet speed can rise to 10m/s. At this time, take samples for analysis to confirm that the natural gas content reaches the replacement standard (more than 45%); Open the inlet valve of the gas tank again to fill the natural gas at a flow rate of no more than 10 m/s until the gas tank rises by 27 m (30000 m3), and the replacement is completed. If the gas tank has been officially operated, the top of the gas tank can be raised to the upper limit.
(5) After the replacement of the cabinet, it is necessary to replace the pipes and valves connected to the equipment. Generally, the volume of this part is not very large. It can be replaced by venting while discharging at the terminal.
The above is the brief information of the editor of the gasholder installation. I hope it can help you.