Ammonia leakage process

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Ammonia Leakage Test Procedure Guide 1 General Provisions 1.1 This procedure guide is specifically prepared for the ammonia leakage test of the company’s product R09-144. The ammonia leakage test uses a G-144 pressure testing fixture. 1.2 The test standard method is carried out in accordance with Appendix A \"Ammonia leakage test method for pressure vessels\" of HG20584-98 \"Technical requirements for the manufacture of steel chemical containers\". 1.3 The main purpose of this test is to check the tightness of the connections between the heat exchange tubes and the tube sheets in the equipment, as well as other connections. To ensure reliable test results, Method B (filling with 10%-30% by volume of ammonia gas) was selected based on the actual characteristics of the company’s products. 1.4 Precautions: a. Ammonia is a flammable and explosive gas; proper fire and explosion prevention measures must be taken at the testing site ； b. Ammonia is toxic; testers and the testing site must take proper measures to prevent exposure to this gas and to ensure isolation ； c. Before the test, oil and other contaminants on the surface of the weld as well as on its sides should be removed thoroughly. d. Before the test, the accumulated water should be drained and dried as much as possible. 2 Preparation Work 2.1 Before conducting the leakage test, the shell side and tube side of the heat exchanger must undergo hydrostatic testing in accordance with their respective requirements, and pass such testing. 2.2 Prepare the following equipment, accessories, instruments, and loading/unloading tools as shown in the attached drawings: a. Liquid ammonia pressure cylinders and pipelines with valves ； b. Nitrogen pressure cylinder and valve-equipped piping ； c. Three-way piping, one end of which is the intake piping with a valve ； d. Ammonia pressure gauges (two with a range of 1.0 MPa, installed on the equipment; one with a range of 4 MPa, installed in the inlet pipeline) ； e. Loading and unloading tools such as adjustable wrenches ； f. Phenolphthalein test paper or phenolphthalein solution reagent. The formula for phenolphthalein solution is 1% phenolphthalein, 50% alcohol, and 50% water. 3 Test Procedure 3.1 Install and connect the piping system as shown in the attached diagram. The exhaust outlet should be slightly lower than the intake outlet to allow air replacement. 3.2 Replace the air inside the equipment with nitrogen in an amount 3 to 5 times the volume of the space (approximately 2 to 4 cylinders). (To ensure an effective replacement, the equipment can first be filled with water and then replaced with nitrogen; any remaining water should be removed as much as possible.) To avoid the formation of ammonia and air pollutants*. 3.3 During the test, it is strictly prohibited to bring any kind of ignition sources into the site or to strike the equipment. 3.4 After the above process has been verified and approved by the safety personnel, the operator shall slowly increase the pressure according to the specifications in the table below: Product number: R09-144. Pressure of nitrogen to be filled: 0.9 MPa. Then, ammonia is added until the pressure reaches 1.0 MPa. Holding time: 4 hours. Ammonia concentration: 10%. 3.5 Apply the leak detection indicator (or test strip) evenly to the tube sheet, ensuring it remains moist at all times. 3.6 Close the valve of the three-way intake pipeline. At the leak detection pressure, the holding time is as shown in the table. Check once after 30 minutes and once after 1 hour from the start of pressure holding; thereafter, check every 2 hours. It is considered successful if no red spots appear on the test strip. 3.7 After the test is completed, open the valve of the exhaust pipeline to release air; the exhaust process should be carried out as slowly as possible. A water tank can be placed near the equipment in advance to allow the ammonia gas to be discharged into the water. 3.8 When the pressure in the equipment drops to 0, open the nitrogen valve and use 2–4 cylinders of nitrogen for purging in order to remove the ammonia from the equipment, then close the valve. 3.9 Conduct on-site cleanup; the inspectors promptly organize the inspection records and fill out the pressure test report. Be especially careful about safety! ! !