In the 1980s, Guangzhou Huaqiao Sugar Factory (carbonic acid method) applied a plate heat exchanger to heat the clear juice. The plate area was 0.79m2, 50 pieces were installed, and the effective heating area was 37.9m2. Using the first juice steam, the juice content is 117t/h, the juice temperature is 68.7°C, the juice temperature is 100.7°C, the temperature rise is 32°C, the steam inlet temperature is 114.2°C, the drainage temperature is 108.4°C, and the heat transfer coefficient K is 4010W/m2. .K, the pressure drop of the clear juice through the heat exchanger is 36 kPa. Its outlet water temperature is about 6 ° C lower than the inlet steam temperature, and there is little water in the tank. If the drainage is smooth, the K value will be higher. The equipment was dismantled and inspected after more than ten days of continuous use, and most of the sheet’s surface was still as smooth as new. There is very little dirt and can be wiped off with a soft cloth.
The Shunde Sugar Factory (sulfuric acid) sugar factory in Guangdong uses a plate heat exchanger with a plate area of 1.07 m2, used as the third stage heating of the clear juice. The average amount of cane juice is 254t/h. The temperature of using waste steam is 129～130°C, the juice temperature before heating is 106～108°C, the temperature after heating is 120～126°C, and the heat transfer coefficient is 2400～3900 W/m2.K.
Guangdong Zhujiang Ganhua Plant uses a plate heat exchanger for the first-grade heating of the clear juice, and the heat transfer area is 35m2. After heating, the juice temperature is only 2 to 4 ° C lower than the steam temperature. After 15 days, the temperature difference is 4 to 6 ° C, and the heating temperature is higher than the 60 m 2 tube heater used. Its heat transfer coefficient is 2700 ~ 4000W / m2.K.
Another sulphite sugar factory uses a plate heat exchanger with a plate area of 0.36m2 and 90 pieces. The effective heat transfer area is 31.68m2. The juice is heated by the first juice steam. The average measured data for seven days is clear juice flow rate 37.2. t/h, juice temperature 76 ° C, juice temperature 107 ° C, temperature rise 31 ° C, steam inlet temperature 113 ° C, steam condensation water temperature 112.5 ° C, heat transfer coefficient 2300W / m2.K. After more than ten days of disassembly, the surface of the plate has very little deposit and can be washed off with water and a soft brush.
The heat transfer performance of the heated juice by the plate heat exchanger is more than double that of the tubular type so that the heat transfer area used can be reduced by half or more. Here, it is better to use the first effect juice, and there is a certain energy-saving effect compared with heating using waste steam. In the case that the heat exchanger has good performance and is close to the evaporation can, the juice is heated by the juice vapour to make the temperature of the juice close to the juice vapour temperature, only 3 to 5 ° C lower, which can meet the needs of evaporation. Heating with juice vapour can also prevent the coking of sugar juice caused by excessive steam temperature. Some sugar factories in China use waste steam. Some factories have been seriously coked due to careless operation, and the char is difficult to remove.