Steam systems are said to be performing at optimum when productivity is high and product output is of superior quality with the lowest possible energy consumption. Precise control of process temperature and steam pressure plays a crucial role in this.
Let’s discuss the importance of precise pressure control in this article.
Importance of Precise Control of Steam Pressure
Precise steam pressure control is critical for process throughput and determines the actual optimum energy consumption at equipment level.
The methods most commonly used are :
- Manual pressure control.
- Pressure control using self-acting pressure reducing valve.
- Pressure control using pneumatic operated PID type pressure reducing valve.
Detailed Comparison of Pressure Control Methods
IMPACT OF IMPROPER SELECTION OF PRESSURE CONTROL METHOD ON THE PROCESS
Reduced Efficiency
Any control system performs four essential functions - measurement, comparison, computation and correction. In a manual control system all these functions need to be performed by the operator. However, manual operation is prone to human error. Lapses in accuracy and continuity can affect the overall efficiency of the process.
Lower Product Quality and Productivity
Inaccurate pressure control results in stratified consumption profiles leading to low product quality, increase in rejections / rework, and therefore lower productivity.
Operational Safety Hazards
Inaccurate pressure to the steam system can also lead to conditions exceeding the design pressure of equipment, increasing the risk of safety hazards.
BENEFITS OF AUTOMATIC PRESSURE CONTROL
Higher Energy Efficiency
In automatic pressure control systems, the four essential functions of the system, i.e. measurement, comparison, computation and correction are done with help of sensor, controller, control valve with actuator and positioner ensuring optimum accuracy and continuity.
PID type pressure control valves provide the right quantity of steam at right pressure at all times. They also ensure energy saving by providing maximum allowable working pressure (MAWP) to the process, which prevents excess steam consumption.
Optimum Product Quality
Accurate control of pressure within desired limits enables consistency in production and ensures optimum product quality, reducing rejection rate / rework for temperature sensitive processes. This further leads to savings in raw material costs.
High Operational Safety
Overheating/ cooling due to inaccurate control may lead to unwarranted / dangerous process conditions. This situation can be eliminated / controlled by automatic pressure control.
The Forbes Marshall Solution
The eVALV from Forbes Marshall is a versatile control valve designed to meet the need of varied process control requirements. It is an innovative 2-port globe valve built to the highest quality standards. Installation of the eVALV on steam lines ensures precise temperature control and controlled utility consumption with optimised and sustained productivity for optimum PQ%.
