Cleaning scheme of heat exchanger
The high pressure water jet cleaning technology of heat exchanger (500-2800bar) is a method of jet cleaning (physical cleaning) for the heat exchanger (also known as heat exchanger) without disintegration. It is a technology of high pressure water jet cleaning by pressurizing common tap water to several 500-1500bar heat exchanger through high pressure pump. A highly dispersed flow of energy emitted at a very high speed (200-500 M / s) through a special nozzle (with a bore of only 1-2mm). The small water flow in this bundle has scattered vibration strike energy, which will not damage the tank wall. It can remove salt, alkali, scale and various blockage from the inner wall of the pipe. The general inner diameter of all kinds of tubular heat exchanger is Φ 10-Φ 50 mm, and the length is about 3M, 6m, 9m and 13m. We use the corresponding length of steel gun and soft gun and nozzle suspension tube of many similar drill bits to strike and clean the fouling in the pipe. After crushing, discharge the pipe with water flow, and clean the fouling blockage inside and outside the pipe efficiently. The cleaning effect in all directions reaches 90% It's on.
1) Application conditions:
1. The pipe holes of the train are blocked or semi blocked, and the surrounding or bottom structure of the pipe holes are cleaned. The high-pressure hard pipe or hose with rotating nozzle spray heads are used to spray the surrounding scaling, and the scale is cleaned and descaled automatically by the jet reaction force;
2. The fouling attachment at the end of the pipe is cleaned by jet cleaning with a face gun (rotating nozzle) with a hand-held rotating high-pressure jet.
2) Construction conditions
1. According to the model of heat exchanger of your company and the site investigation and your technical requirements, it is unnecessary to take out the core of the train pipe, remove the end cover at both ends horizontally, and conduct isolation protection. The water collection cloth (canvas) is laid outside the working surface to protect the surrounding equipment from the pollution caused by high-pressure jet splashing;
2. There is no obstacle in the cleaning site (within 2m around the pipeline) of your company;
3. Your company provides the access to the site (about 3M) for power, water, lighting facilities and operation equipment (high-pressure cleaner), and high pressure cleaning unit (container container type storage site 2.5 * 5m2).
chemical cleaning
Principle flow of shell side circulation cleaning of oil and gas pipe of heat exchanger (chemical cleaning)
1. The circulation system in the train pipe is established:
2. The circulation system outside the train pipe is established;
3. Alkaline cleaning agent is used for oil dirt: the proportion shall be carried out according to relevant standards;
4. Scale type acid cleaning agent: according to relevant standards to carry out the proportion.
Construction scheme of chemical cleaning on oil and gas side
The effective pipe side of oil side is designed with material, diameter and number of roots. During the operation of heat exchanger, oil sludge and oil scale will be formed when oil and gas medium flows through the shell metal and the surface of the tube. In serious cases, the oil scale coking will gradually deposit on the metal surface, especially in the dead angle area with low flow rate. This will lead to the gradual decline of heat exchange efficiency of heat exchanger, which seriously affects the heat exchange effect of equipment. In addition, the presence of sediment will cause corrosion under scale, and local corrosion is an important factor for the perforation of heat exchanger.
According to the site and oil scale, the gas side cleaning of the heat exchanger is carried out by selecting the circulating chemical cleaning process. The process has the following advantages: the cleaning solution can maintain a certain temperature and concentration; the cleaning liquid circulation has the function of stirring and washing and stripping, which helps to remove the oil and oil scale which is not easy to remove.
1、 Preparation before chemical cleaning:
1. Take the tube for simulation test, determine the test formula and cleaning scheme.
2. Clean pump station, raw materials, connecting rubber pipe and other equipment and auxiliary parts to the site. Install circulating pump and temporary cleaning pipeline, etc., and connect to a complete cleaning system.
3. Do well in all kinds of personal protection measures. Such as protective glasses, towels, masks, rubber gloves, acid and alkali resistant work clothes and acid alkali resistant rubber shoes.
4. Prepare tools and tools such as spanners, iron wire, rubber, clamps, etc.
5. Remove or effectively isolate all instruments of pre cleaning equipment and parts not involved in cleaning.
Technical and safety disclosure shall be conducted to the construction personnel to make them understand the cleaning system, operation regulations, performance of cleaning agent and all safety construction measures.
2、 Chemical cleaning procedure
Water washing cleaning cleaning water washing end air drying of compressor
1. Water flushing
(1) Remove the dirt, sediment and water in the dissolving tank and clean the tank.
(2) Start the circulating pump with industrial water to fill the solution tank and the cleaned equipment and the whole circulation system with clean water, stop adding water, and observe whether the cleaning system has leakage for half an hour when the valve reaches the maximum opening (discharge valve is fully closed). If there is any leakage, it shall be handled in time.
(3) Stop the pump for half an hour, open the drain valve and try to drain the sewage from the system.
(4) Repeat the (2) (3) two steps until the water is visually free of obvious debris, etc. to carry out the next cleaning work. 2. Cleaning agent cleaning
(1) Add clean water to the solution tank, start the circulating pump, establish a cycle in the cleaning system, add the metal corrosion inhibitor and cleaning agent to the solution tank to establish a cycle, and adjust the temperature to 50-80 ℃.
(2) After the start of dosing, the concentration of cleaning solution was analyzed, once 15 minutes to half an hour.
(3) The cleaning time of the agent should be determined according to the oil concentration, the change of the effective composition and the flow rate of the liquid. The cleaning time is about 2-5 hours due to the small inlet and outlet diameter of the equipment. Observe the change of water quality of the circulating cleaning to consider whether to extend the cleaning time or the second cleaning.
3. Water flushing
(1) Discharge the cleaning solution, add clean water to the solution tank for water flushing, start the circulating pump, fill the whole system with clean water, and finish flushing when there is no obvious dirt in the water.
(2) Then when the pH value is about 7 when the water is replenished, open the discharge valve and drain the water from the equipment as far as possible, so that the cleaning is finished.
4. Air drying of compressor
(1) Remove the cleaning connection pipe and connect the compressed air.
(2) Open the oil cooler drain valve and use compressed air to dry the equipment up and down repeatedly.
3、 Waste liquid treatment
The treatment of cleaning waste liquid shall be strictly carried out in accordance with Party A's requirements and discharged to the designated place after hazardous treatment.
4、 Construction precautions
1. The construction personnel must wear labor protection articles as required when entering the site, and they need to wear rubber shoes, rubber gloves, masks and eye masks.
2. The construction site shall be well ventilated and the operation site shall be provided with convenient and sufficient water sources.
3. When handling corrosive drugs, it is strictly forbidden to splash into eyes, mouth and skin. If it is touched by mistake, wash with plenty of water immediately. If serious, immediately treat the burn according to strong acid and alkali.
4. Construction drugs shall be placed in cool and ventilated places, and marked with "dangerous goods not moving", sealed and kept for a long time.
