Model-based Electric Regulating Valve Design in Looped Steam Heating System User-side Temperature Control

A significant challenge in existing multi-source looped steam heating system management is the unstable steam quality (temperature, pressure) at the user side due to the mal distribution of mass flow rate between the steam loops. This issue could be mitigated with electric regulating valves. Due to the steam heating system’s complexity, the impact of the valves is less discussed and quantified. This study investigates the operation of electric regulating valves with a focus of the improvement on user-side steam temperature. This study develops a steam heating system model and proposes a steam dissatisfaction factor to quantify steam temperature improvement at the user side. The centerpiece of the model includes the topological representation of the steam heating system based on graph theory. The methodology and quantification approach are validated and further discussed in a chemical industry park in Shanghai with four heating sources. Analysis and comparison of different valve usage and installation scenarios show that the pipe-line’s resistance characteristics are adjusted, and the distribution ratio of the mass flow between the loops changes with the introduction of valves. Electric regulating valves installed locally within the loop better-enhance the users’ temperature when compared with one installed at the entry of the loop. However, a proper valve opening needs to be selected to lift the user-side temperature. As found in the case study, a valve opening of 60% minimizes dissatisfaction compared with single-source supply. It is critical to dynamically adjust the valve opening to ensure the effectiveness of electric regulating valves. Moreover, it is necessary to avoid a valve installation location in the low-temperature steam feeding region.