Heat Exchanger (heat Exchanger) Cleaning Methods 3
Chemical cleaning
Principle process of cyclic cleaning in the shell side of the oil and gas pipe side of the heat exchanger (chemical cleaning)
1. Establish the circulation system in the tube:
2, the circulation system outside the tube is established;
3. Use alkaline cleaning agent for oily dirt: perform the ratio according to relevant standards;
4. Try acidic cleaning agents for scales: perform the proportioning according to relevant standards.
Oil and gas side chemical cleaning construction plan
The material, diameter, and number of effective pipes on the oil side are designed. During the operation of the heat exchanger, oil sludge and grease will be formed when the oil side oil and gas medium flows through the surface of the heat exchanger tube shell and the tube. In severe cases, the grease and coking will gradually deposit on the metal surface, especially in the dead corners where the flow rate is low. within the area. This will lead to a gradual decline in the heat exchange efficiency of the heat exchanger, which will seriously affect the heat exchange effect of the equipment. In addition, the presence of deposits can also cause corrosion under scale, and local corrosion is an important factor in perforating heat exchangers.
According to the site and the grease condition, the air side cleaning of the heat exchanger uses a cyclic chemical cleaning process. This process has the following advantages: the cleaning fluid can maintain a certain temperature and concentration; the cleaning fluid circulation has the effect of stirring, scouring and stripping, which is helpful It is used to remove oil stains and grease stains that are not easy to remove.
1. Preparation before chemical cleaning:
1. Take a test tube to do a simulation test to determine the test formula and cleaning plan.
2. Clean the pump station, raw materials, connecting hoses and other equipment and accessories and transport them to the site. Install the circulating pump and clean the temporary pipeline, etc., and connect them to form a complete cleaning system.
3. Take various personal protective measures. Such as protective glasses, towels, masks, rubber gloves, acid and alkali resistant overalls and acid and alkali resistant rubber shoes.
4. Prepare tools such as wrenches, wire, rubber, clamps, etc.
5. Dismantle or effectively isolate all instruments of the pre-cleaning equipment and parts that are not involved in cleaning.
Provide technical and safety clarifications to the construction personnel to make them understand the cleaning system, operating procedures, cleaning agent performance, and various safety construction measures.
2. Chemical cleaning steps
Water rinse-detergent cleaning-water rinse-end of cleaning-compressor air blow dry
1, rinse with water
(1) Remove the dirt, sand, and stagnant water in the dissolving tank, and wash the tank clean.
(2) Using industrial water, start the circulating pump to fill the dissolving tank, the equipment to be cleaned and the entire circulating system with clean water, stop adding water, and circulate the valve to the maximum opening (the discharge valve is fully closed) for half an hour to observe whether the cleaning system leaks. If there is any leakage, deal with it in time.
(3) Stop the pump for half an hour, open the discharge valve, and try to drain the sewage in the system.
(4) Repeat the two steps (2) and (3) until the water has no obvious sundries, etc., then the next cleaning work can be carried out. 2. Cleaning with detergent
(1) Add clean water to the dissolution tank, start the circulation pump, and establish a cycle in the cleaning system. At the same time, add a metered amount of metal corrosion inhibitor and cleaning agent to the dissolution tank to establish a cycle. The temperature is heated to 50-80°C.
(2) The concentration analysis of the cleaning solution is performed immediately after the start of the dosing, once every 15 minutes to half an hour.
(3) The cleaning time of the medicament needs to be determined according to the concentration of oil stains carried out by the liquid, the change of the effective ingredients of the medicament and the flow rate. Due to the small inlet and outlet diameter of the equipment this time, the cleaning time is about 2 to 5 hours. Observe the changes in the water quality of the cycle cleaning and consider whether to extend the cleaning time or second cleaning.
3, rinse with water
(1) Drain the cleaning solution, add clear water to the dissolution tank for water flushing, start the circulating pump to fill the entire system with clear water, and finish the flushing when there is no obvious dirt in the water.
(2) Then, while replenishing water and draining until the PH value is around 7, open the drain valve to drain the water as much as possible from the equipment, and the cleaning is complete.
4, the compressor air is blown dry
(1) Remove and clean the connecting pipes and connect the compressed air.
(2) Open the drain valve of the oil cooler and use compressed air to dry the inside of the equipment repeatedly.
Three, waste liquid treatment
The cleaning waste liquid shall be treated in strict accordance with the requirements of Party A and be discharged to the designated place after hazardous chemical treatment.
Four, construction matters needing attention
1. When entering the site, the construction personnel must wear labor protection supplies according to the regulations. They must wear rubber shoes, rubber gloves, masks and eye masks.
2. The construction site must have good ventilation, and the operation site must have convenient and sufficient water sources.
3. When transporting corrosive drugs, it is strictly forbidden to splash them on the eyes, mouth and skin. If touched by mistake, rinse immediately with plenty of water. In severe cases, seek medical attention immediately for burns caused by strong acid or alkali.
4. The construction drugs should be placed in a cool and ventilated place, with eye-catching notes such as "Do not move dangerous goods", sealed and stored for long-term effectiveness.
