Comparison between plate and tube evaporation

Thread Content

I. Advantages of plate evaporators over shell-and-tube evaporators Compared to traditional shell-and-tube evaporators and condensers, GOJE’s plate evaporators and condensers offer unimaginable benefits. They not only take up less space, thus saving valuable area, but also **reduce investment costs and maintenance needs, without compromising reliability and safety. In terms of energy savings, plate evaporators and condensers enable counterflow heat transfer during evaporation, which **reduces the temperature difference between the two ends, while shell-and-tube units can only achieve cross-flow heat transfer, thereby reducing the amount of steam required for heating. 1. High heat transfer efficiency: The special corrugated plate design generates intense turbulence, resulting in a significantly higher heat transfer coefficient compared to traditional shell-and-tube evaporators. The GOJE plate evaporator is particularly effective at high concentrations and high viscosities, and it can operate with a temperature difference of only 3–5°C, which is a significant advantage when it is used in TVR and MVR systems. In the case of TVR systems, a shell-and-tube evaporator is used together with a steam heat pump; the secondary steam extraction ratio is very low, at only 1:0.5. This is because for a shell-and-tube evaporator, the minimum temperature difference required for evaporation in the first stage is 15°C, which means that the steam entering the evaporator must have a high temperature, and it is only possible to draw in a small amount of low-temperature secondary steam. With a plate evaporator, the steam injection ratio can be maintained at above 1:1.25, **reducing the consumption of raw steam. 2. Less scaling, easier maintenance – The high-intensity turbulence throughout the plate pack not only reduces scaling but also makes chemical cleaning more effective. Compared to shell-and-tube types, less cleaning agent is required due to the lower amount of residue. The flexible design of the GOJE plate evaporator means that the heat transfer surface is easy to inspect and can be cleaned mechanically by simply removing the fastening bolts and loosening the pressing plates. 3. Easy to scale up A popular feature of GOJE plate evaporators is that to increase or decrease capacity, it is sufficient to add or remove plate sets to the existing frame. This is a major advantage compared to shell-and-tube evaporators (whose production capacity is fixed at the time of installation). 4. Improving product quality: The very low retention volume means that almost no product remains inside the plate evaporator at any given time. The product stays inside the evaporator for a short time, which is a great advantage for heat-sensitive products. It also allows for quick startup and shutdown, with only minimal waste. 5. Reduced user costs – The unique design of GOJE plate evaporators and condensers results in higher thermal efficiency compared to traditional shell-and-tube equipment, which means that the required heat exchange area is **reduced**. Therefore, using GOJE plate evaporators and condensers is very economical, especially when special metals such as SMO, titanium, nickel and nickel-based alloys, and Hastelloy are required. 6. Space and installation cost savings As can be seen from the schematic diagram below, it is a three-effect evaporation system. It is clear that compared to traditional shell-and-tube types, the GOJE plate evaporators and condensers allow for **savings in installation costs and space required for installation. Comparison of floor space required by plate-type evaporation systems and shell-and-tube evaporation systems: https://attach01.hcbbs.com/forum/201906/14/152642tjphj47h22fh2kf7.jpg II. Introduction to plate-type evaporator series 1. Rising-film plate-type evaporator: Each unit consists of two plates of different designs; the material enters from the middle at the lower end of the plates, while the vapor-liquid mixture exits from the larger opening at the upper end of the plates ； Steam enters through the small irregular opening at the upper end of the plate, while condensate exits through the openings on the left and right sides at the lower end. Low-resistance corrugations are used to ensure a uniform distribution of the medium, resulting in low resistance and high efficiency. https://attach01.hcbbs.com/forum/201906/14/152709bmd7a7jxr7mxd81m.jpg 2. Rising-film plate evaporator: A rising-film plate evaporator consists of 4 plates, with 4 channels between them. The material enters at the left and right openings at the bottom of the first channel (rising film), passes through the top of the plates via the second channel to reach the third channel, and then exits through the large opening at the bottom (falling film) ； The first and third channels are both steam channels; steam enters from the side openings on the plates, and after heat exchange, the condensed water exits from the side at the bottom of the plates. https://attach01.hcbbs.com/forum/201906/14/152735d0c3lr9les0rlzrq.jpg 3. Falling-film plate evaporator: Each set consists of two plates of different designs; the material enters through the openings on the upper sides of the plates, while the vapor-liquid mixture exits through the larger opening at the lower center ； Steam enters through the large opening in the middle at the upper end of the plate, while condensed water exits through the openings on the left side at the lower end. Low-resistance corrugations are used to ensure a uniform distribution of the medium, resulting in low resistance and high efficiency. https://attach01.hcbbs.com/forum/201906/14/152802w9enhyangxhey2yn.jpg This falling film plate further improves the efficiency of evaporation equipment, enabling it to handle materials with large throughput, high concentrations, and high viscosities.