(1) According to the blockage and the nature of the scale, a certain concentration of chemical cleaning solution is prepared in proportion, and the addition amount of each component is continuously adjusted.
(2) Prepare cleaning agent. It is selected to be composed of a dozen chemicals such as sodium carbonate, caustic soda, penetrant, surfactant, emulsifier, etc., and formulated into a cleaning solution with a concentration of 10%.
(3) The inlet temperature of the cleaning solution is 55°C, and the outlet temperature is 30°C. The temperature of the inlet cleaning solution can be adjusted according to the composition of the scale medium.
(4) Adopt a cleaning method that combines soaking and circulation. Generally, it needs to be soaked for 15-20h, and then forced to cycle for 6h.
(5) The cleaning product is a thick black liquid with flocculent tar, which will form a paste when it flows on the ground, weighing about 50-80kg.
(6) After cleaning to a certain level, open the inlet and outlet of the spiral plate heat exchanger to observe the degree of tar cleaning, then add the "oil washing king" and adjust the formula appropriately, and pump into the waste ammonia channel of the heat exchanger. At the same time Steam is introduced at the entrance of the circulating water channel for heating, which causes the tar to be dissolved in the "washing oil king" solution to the greatest extent and discharged, and circulates multiple times in sequence.
(7) After cleaning, carry out pickling to remove scale. The inlet temperature of the pickling solution is 50°C, and an appropriate amount of corrosion inhibitor is added from a 6% hydrochloric acid solution. During the pickling process, gas is discharged and foam is generated. When the pickling is terminated, the acid solution concentration is 3.5%, and the black liquid is discharged.
(8) After acid washing, perform alkaline washing and neutralization, add a mixed liquid composed of caustic soda, sodium carbonate, and trisodium phosphate to soak and circulate for 6 hours until the black liquid is exhausted.
(9) Rinse with clean water until the pH value is 7, and the rinse is over.