Applications of Plate Heat Exchangers in Beverage Industry

In recent years, with the improvement of people's living standards and the demand for beverages, the beverage industry has been rapid development. For the pursuit of low-cost, high efficiency, many beverage plants expand the scale of production continually, and beverage machinery and equipment to large-scale, continuous, automated production direction. On the other hand, according to the needs of market diversification, especially some agricultural and sideline products processing have seasonal characteristics, it requires equipments to adapt to multi-purpose production, to establish a variety of varieties, a small amount and cost-effective production system. Therefore, as the most basic operation in beverage processing --- using plate heat exchangers to heating, sterilization, cooling should also be more varieties, small batch production, which is necessary to be able to heat the various properties of raw materials, but also to process season product. It extends the scope of application, as well as improves the operational efficiency. As the beverage processing is increasingly complex, you design and manufacture heat transfer equipments must based on the industry's own production characteristics, and at the same time the use of production equipment in operation, you should also pay attention to prevent the attachment of the scale, and take effective cleaning, sterilization and other control microbial reproduction basic measures.

1. The basic application requirements of heat exchangers in the beverage industry

Beverage production has its unique way: the production equipment always contact with water; suffer high humidity; often operated in high temperature or low temperature; work in a large different temperature working environment; touch with beverage and corrosive media directly; and show higher erosion on the equipment materials. Therefore, different from the general industrial heat exchangers, the heat exchangers used in the beverage industry have its own characteristics and requirements on the design and manufacture, operation.

1.1 On the safety of beverages

Materials that are in direct contact with the beverage should be stable and should not contain elements that are harmful to human health or have a chemical reaction with the beverage. Usually the material selection contacted with the beverage side is stainless steel. Non-metallic materials such as gaskets and seals must conform to the hygienic and quarantine requirements of the beverage medium and the relevant provisions of the national health and quarantine organ.

1.2 Easy to clean, easy to disassemble

The side contacted with beverage must be smooth; the welding point must have no pores, slag or gap, seamless; and the container bottom should have 1/100 inclination to prevent water store; pipe joints bolts should use the trapezoidal thread easy to clean. Plate heat exchangers are heat exchange equipments developed by plate and frame filter presses that are easy to tear down. At present, the beverage plant equipments are cleaned by CIP system, less demolition and manual hand washing, but in order to check and replace parts regularly, easy to disassemble is still very important. Easy to disassemble and simple structure of the parts are conducive to the maintenance of equipments to extend the life of them. Plate heat exchanger is efficient and energy-saving heat exchange equipment, because of its high heat transfer efficiency, good sanitation conditions, heating cost economy, strong adaptability, and small size, compact structure, easy to disassemble, clean, easy maintenance and so on, widely used in the beverage industry in a variety of liquid heating, cooling, sterilization and other conditions.

1.3 Reduce the accumulation of residual liquid in the container

To prevent foreign matter mixed in the small batch, multi-species processing, to reduce the residual heat within the heat exchanger can minimize the loss of production varieties, and can shorten replacement and cleaning time. Sealing material damage, heat transfer surface corroded off and leakage within the container all will lead to foreign matter mixed. This is often encountered in industrial production problems, but for the beverage industry, foreign matter mixed with drinks, which should be absolutely prevented.

In the application of the beverage industry, the structural characteristics of the plate heat exchangers

(1) High heat transfer coefficient. Since the different corrugated plates are inverted to form a complex flow path, the fluid flows in a three-dimensional flow in the flow path among the corrugated plates, and turbulence can be generated at a lower Reynolds number (generally Re = 50 to 200), so the heat transfer coefficient is high, generally considered to be 3 to 5 times of shell-and-tube heat exchangers.

(2) Not easy to scale. As the internal water turbulence, not easy to scale, the scaling factor is only 1/3 to 1/10 of tube heat exchangers.

(3) Compact structure, small size, especially for the old factory transformation, which can take full advantages of the original equipment, to overcome the limitations of space occasions. With light weight, thin heat board, less metal consumption, per square meter heating area consume 10kg metal only 1/3 to 1/4 of tube heaters.

(4) Heating materials in the heater stay a short time, with less internal dead angle, good health conditions.

(5) The fluid flow distribution of heat transfer surface is relatively uniform; material heating time is short, which will not produce overheating.

(6) The fluid movement in the channel between heat exchanger plates is intense, and the surface is smooth, the fouling is less, working cycle is long and they are easy to use chemical cleaning. it significantly reduce the small inspection or downtime that need manpower, material and financial resources.

(7) Heating, cooling and heat recovery are easy, combined into a whole, completed at the same time in one heat transfer equipment. As long as regarding the heated material as a heat source to preheating the fluid, you can achieve the operating requirements that each one of two fluids need to be cooled or heated. Do both, save energy, and the processing equipment is compact.

Plate heat exchangers are widely used for high temperature short time (HTST) and ultra high temperature (UHT) sterilization in the processing of fruit juices, refreshing beverages and beer. Of course, there are obvious shortcomings, to attract enough attention, mainly:

(1) The heat exchanger plate is thin, low pressure capacity; especially the contact point between the corrugated boards, mutual support type of heat exchanger, if the use of age, compact size is beyond the installation requirements size, it is easy to make the contact point into the pit, and to form perforation to scrap the plate.

(2) The spacing between the plates is narrow, the liquid film is thin, and the evaporation speed is fast. If the high-temperature steam and liquid materials as a hot and cold medium for heat transfer, in the case of material suddenly shut down, it is prone to dry coking phenomenon, to accelerate the sealing gasket between the plate damage. Coking material can block cold material channel block, affecting the use of equipment, to losses production. So, the staff of the plate heat exchanger equipment structure and understanding of the working principle is the difficulties in the actual use.

(3) The pressure loss of per unit length is large. As the gap between the heat transfer surfaces is small, the heat transfer surface has irregularities, so the pressure loose is bigger than the traditional smooth tube.

  Read original by Crystal Zhai