Although plant-based protein products are receiving increasing attention and awareness of the environmental impact of intensive livestock farming systems is becoming more pronounced, global meat consumption continues to rise, and the number of pets is also on the rise. Alongside this, the market for meat processing by-products and ingredients for pet food is expected to grow significantly. In this context, maintaining the quality of meat and by-products through temperature control and proper handling plays a crucial role in maximizing product value and minimizing losses during production.
Technical challenges for meat and by-products
The process of slaughtering and processing meat and poultry always generates many types of by-products and surplus materials. In the past, most of these by-products were converted into commodity products such as meat meal, bone meal, and blood meal for use in animal feed or fertilizers. However, with the development of technology and the increase in population, the demand for valuable by-products is rising, including poultry offal, bones, blood and plasma, fats, oils, gelatin, mechanically separated meat (MSM), and other edible protein components.
To maximize the value of these raw materials, processing equipment must ensure the production of high-quality products at low costs, reduce raw material loss, and consume less energy. This requirement also similarly applies to main products such as minced meat juice and derivatives from MDM. In actual production, heat exchange equipment is used for various purposes such as heating, cooling, pasteurization, sterilization, and concentration.
However, meat ingredients have a high tendency to adhere, which reduces heat transfer efficiency, and they also have a sensitive structure that requires gentle handling to maintain quality. Due to their high viscosity, meat products may exhibit thermal stratification during heat treatment. When using tube-in-tube heat exchangers, the portion of the product near the tube wall is cooled or heated more intensely, while the center part is not mixed evenly, creating a temperature difference within the same product stream. This can lead to localized freezing in the area close to the tube wall during cooling, while the center part has not yet reached the required temperature, or uneven heating of the cold product.
Scraped Surface Heat Exchangers (SSHE)
To address the phenomenon of thermal stratification, a ring-shaped space heat exchanger can be used, where the heat transfer medium passes through the center while simultaneously surrounding the product flow. However, this design is not suitable for products containing particles or solid pieces. Therefore, for high-viscosity meat products or those containing solid components, a scraped surface heat exchanger is often the optimal choice.
This device allows for gentle processing of products while continuously creating an even mix to prevent thermal stratification and reduce fouling on the heat transfer surface. Additionally, the device has high mechanical durability to meet heavy load operating conditions. The scraped surface heat exchangers are designed with an improved internal scraping configuration and a high-power gearbox to withstand high torque when processing products with high viscosity, especially at low temperatures.
The high-speed moving scraper increases the heat transfer coefficient, thereby reducing the heat exchange surface area, lowering operating pressure, decreasing equipment size, and reducing investment costs. Additionally, the scraper bar and the screw shaft system inside the tube can reverse direction to push all products out of the equipment without altering their structure, contributing to reduced material loss during the cleaning-in-place (CIP) process and when switching products.
Scraped surface heat exchanger with translational motion
In some cases, a scraped surface heat exchanger with a reciprocating motion will be a more suitable solution, especially for products with high viscosity and strict requirements for structure and uniformity. This equipment allows for efficient heat transfer at low pressure, thereby minimizing the risk of structural breakdown due to the high shear forces that may occur when operating at high pressure and speed.
Thanks to these advantages, the device can be applied in various processes such as cooling poultry offal and pet food ingredients, cooling mechanically deboned meat (MDM), as well as heating or cooling animal blood.
Source: HRS Heat Exchangers.