How Steam Pressure and Tank Jacket Affect the Temperature Control of Process Liquid Inside the Tank

Temperature control is a critical factor in many industrial processes that involve storing and mixing liquids or materials in tanks. Temperature affects the viscosity, density, solubility, reaction rate, and quality of the process liquid. Therefore, maintaining a precise and uniform temperature inside the tank is essential for optimal process performance and product quality.

One of the most common methods of heating a tank is by using a jacketed tank. A jacketed tank is a tank that has an outer layer covering the original tank shell where the heating or cooling medium flows between the surfaces, which results in efficient and uniform thermal transfer to the tank content. One of the most common heating mediums used in jacketed tanks is steam, which has many advantages over other mediums, such as high heat capacity, low cost, and easy availability.

Steam Pressure and Tank Jacket

However, using steam for heating a jacketed tank also poses some challenges, such as choosing the right steam pressure for the jacket and the tank. The steam pressure of the jacket and the tank affects the temperature control of the process liquid in several ways, such as:

  • Determining the steam temperature: The steam temperature is directly related to the steam pressure by the saturation curve. Higher steam pressure means higher steam temperature and vice versa. The steam temperature determines the heat transfer rate from the steam to the process liquid through the jacket wall. Higher steam temperature means higher heat transfer rate and vice versa. Therefore, choosing the right steam pressure for the jacket and the tank depends on the desired temperature and heat transfer rate for the process liquid.
  • Influencing the overall heat transfer coefficient: The overall heat transfer coefficient (U) is a measure of how well heat is transferred from one fluid to another across a solid surface. It depends on several factors, such as the thermal and transport properties of both fluids, the surface area and geometry of the heat transfer surface, and the temperature difference between the fluids. The overall heat transfer coefficient affects the heat transfer area required for a given heat transfer rate. Higher overall heat transfer coefficient means lower heat transfer area required and vice versa. Therefore, choosing the right steam pressure for the jacket and the tank depends on the available heat transfer area and the required overall heat transfer coefficient for the process liquid.
  • Causing condensate accumulation and water hammer: When steam flows through a jacket, some of it may condense on the jacket wall due to heat transfer to the process liquid. The condensate may accumulate inside the jacket and reduce its effective cross-sectional area, which increases the steam velocity and pressure drop. This may affect the steam flow rate and temperature control of the jacket and the tank. Moreover, if there is a sudden change in steam flow rate or pressure, such as during start-up or shut-down, the condensate may be pushed along with high-velocity steam and cause water hammer, which is a phenomenon of shock waves and noise caused by rapid changes in fluid momentum. Water hammer may damage the jacket or its fittings and valves, and affect its performance and safety. Therefore, choosing the right steam pressure for the jacket and the tank depends on avoiding condensate accumulation and water hammer inside the jacket.

In summary, there is no definitive answer to what steam pressure to use for heating a jacketed tank, as it depends on various factors and conditions. The best way to determine the optimal steam pressure is to consult with a qualified engineer or manufacturer who can perform a detailed heat transfer analysis and provide a customized solution for your heating needs.

At Plygen Industries, we supply several different kinds of tanks with various types of jacket configured at different steam pressures. We can fully customize the stainless steel vessel just for your process need. Contact us today. With industrial-leading short lead time, we can quickly deliver your order to help you jump-start your project.