How to deal with excessive pressure drop of spiral heat exchanger?

1. Clean the dirt or plate scale in the channel of spiral plate heat exchanger, and clean the newly-run system once a week according to the actual situation. Clean the scale (mainly CaCO) on the surface of the board. ), choose 0.3 sulfamic acid solution or 0.8 nitric acid solution containing 0.3 urotropine, 0.2 phenylethylamine and 0.1 potassium thiocyanate as the cleaning solution, and the cleaning temperature is 4o ~ 6o℃. When the equipment is not disassembled for chemical immersion cleaning, the inlet and outlet of the cold medium of the spiral plate heat exchanger should be opened, or when the equipment is installed, a DN25 cleaning port should be installed at the inlet and outlet of the medium, and the prepared cleaning solution should be injected into the equipment. After soaking, the residual acid should be cleaned with clean water to make the pH≥7. When disassembling, soak the plate in the cleaning solution for 30 minutes, then gently brush off the scale with a soft brush, and then clean it with clean water. Avoid damaging the printing plate and rubber pad when cleaning. If mechanical backwashing without disassembly is adopted, a nozzle should be connected to the medium inlet and outlet pipeline in advance, and the equipment should be connected to the mechanical cleaning vehicle. Cleaning solution should be injected into the equipment in the reverse direction of medium flow, with circulating cleaning time of 1 o ~ 15 min, medium flow rate of 0.05 ~ 0.15 m/s, and then circulating with clean water for several times to control the mass concentration of Cl in clean water below 25 mg/L.

2. Soft water after softening treatment should be used as far as possible for secondary circulating water of spiral plate heat exchanger. Generally, the mass concentration of suspended solids in water is not more than 5mg/L, the diameter of impurities is not more than 3mm, and the pH is ≥ 7 ≥ 7. When the water temperature is not greater than 95℃, the concentration of calcium and magnesium should not be greater than 2 mmol/L; When the water temperature is higher than 95|C, the concentration of calcium and magnesium should be no more than 0.3 mmol/L, and the concentration of dissolved oxygen should be no more than 0.1 mg/L.

3. For the central heating system, one or two times of water replenishment can be adopted.

In addition, the spiral plate heat exchanger has the characteristics of high elasticity, convenient disassembly and assembly, long service life, etc. The range of materials that can be treated is wide, from ordinary industrial water to high viscosity liquid, from food liquid and medical materials with high hygiene requirements to acid-base liquid with certain corrosiveness, from liquid materials containing granular powder to suspended liquid containing a small amount of fiber.

For the spiral plate heat exchanger with large change of medium flow and pressure, multi-pass combination and long-term use, plate dislocation is easy to occur. When the plate is out of position, sometimes it will leak quickly, so it needs timely treatment.

The main causes of dislocation are: plate deformation of spiral plate heat exchanger; The gasket slides out of the gasket groove of the plate. In order to deal with this dislocation, the deformed plate and the rubber pad sliding out of the gasket groove should be replaced in time. In the absence of on-site maintenance equipment, the spiral plate heat exchanger should be simply treated. During use, whether the plate is deformed, cracked or perforated, or the rubber pad is aged, broken or misplaced, it needs to be replaced in time.

If there are no spare parts on site and the spiral plate heat exchanger can't stop, simply handle it on site. On-the-spot treatment method is to draw out the damaged plate and the leaking plate in pairs (plate A+plate B). If the number is small, the number of runners will not be reduced too much, and it can be used continuously after assembly, which will not have much influence on heat exchange.