The study began with a feasibility assessment of the current condensate recovery system. The goal was to understand how the boiler, deaerator, and seven blenders are connected, and to evaluate whether the condensate produced could be effectively recovered and reused. In the existing setup, steam generated at 110˚C and 2.5 bar is supplied to seven blenders, additive tanks, and a hot water system. The flow process for the current condensate recovery system is illustrated in Figure 1 .

During heating, the steam condensed into hot water. Most of the condensate from the blenders is discharged directly into drains, while only condensate from the additive tanks and hot water system is collected and returned to the deaerator. The returned condensate typically reaches the deaerator at 40˚C - 50˚C, but large amounts of hot condensate are wasted. To assess recovery potential, samples of condensate discharged from the blenders were manually collected in 18 L pails. Field measurements were conducted using calibrated digital thermometers with an accuracy of ±0.5˚C and portable pH meters with a precision of ±0.05. Data were recorded at 30-minute intervals during peak operation to capture representative system performance. Each sample was tested for temperature and pH, as illustrated in Figure 2 . Results showed that condensate temperatures reached as high as 95˚C, demonstrating significant potential for energy recovery.

Based on the feasibility study, a new system layout was designed to recover condensate from all seven blenders as illustrated in Figure 3 . The design includes three design considerations:

1) Condensate Header Integration

A 6-inch condensate header connects all blenders, directing condensate efficiently to a central line instead of discharging it into drains. This ensures balanced flow and reduces localized pressure losses.

2) Automated Pumping and Control

A new pumping system with automatic control is integrated through a PLC. The pump is designed to manage both steam and hot water return while maintaining safe suction head (NPSHa > NPSHr). This minimizes cavitation risks and ensures reliable operation.

3) Condensate Conditioning and Return

The collected condensate, typically at 60˚C - 100˚C, is routed to the deaerator. There, it is mixed with treated water and preheated before returning to the boiler. Mechanical steam traps are installed at each blender outlet to prevent steam loss and maintain system pressure.

This design captures condensate from all blenders, retains heat quality, and reduces both water and fuel consumption. In addition, it standardizes the recovery process across all units, which simplifies maintenance and monitoring. The centralized header and automated control system also provide flexibility to handle varying production loads without compromising efficiency.

To validate the proposed design, simulations were carried out using Pipe Flow Expert software. This software models pipe networks, calculates flow rates, pressure drops, and pump performance, and helps identify system inefficiencies. Two blender groups were considered:

Simulation inputs included pipe specifications (diameter, roughness, length, loss coefficients), flow data (mass flow, velocity, volume), and pressure conditions at each node. Energy losses from friction, fittings, and pumps were also analyzed. The results confirmed that the new layout could handle variable loads, maintain safe operating pressures, and minimize energy loss before implementation at full scale.

The control system for transferring condensate from the collection tank to the deaerator was simulated using Festo Fluidsim. Circuit diagrams were developed to include pumps, valves, and sensors. The simulation tested two main operating states:

This simulation confirmed the functionality of automatic level control and reliable water transfer, reducing dependence on manual operation. It also demonstrated reliable water transfer, as the condensate was discharged to the deaerator at the correct timing and flow rate. This prevented overflow, dry running, and unnecessary interruptions. Through sensor-based actuation, the system reduced dependence on manual monitoring, minimized human error, and improved both safety and efficiency.

In the feasibility study, data collection was carried out to evaluate the operation and performance of the existing condensate recovery system. Key parameters recorded included the date, blender ID, blender size, blender capacity, condensate volume, pH, and temperature.

Measurements were taken over seven days across different blenders. On the first day, Blender 1 (15,000 - 43,000 L capacity) recorded a working volume of 29,648 L. It produced 289 L of condensate per blend, with a pH of 8.01. The maximum condensate temperature was 90.2˚C, with an average of 55.2˚C. On the second day, Blender 3 (9000 - 30,000 L) had a capacity of 10,068 L. It produced 207 L of condensate, with a pH of 9.78 and a temperature reaching 101˚C, averaging 91˚C.

In addition to temperature and pH, condensate quality parameters were analyzed to ensure suitability for boiler reuse. The measured values were as follows: total dissolved solids (TDS) < 50 ppm, hardness < 1 ppm, and final pH in the range of 8.0 - 9.8. These results comply with standard boiler feed-water specifications, which typically require TDS < 200 ppm, hardness < 2 ppm, and pH between 7.5 - 10 [2] . Compliance with these limits ensures that the recovered condensate can be safely returned to the deaerator without risk of corrosion or scaling.

Overall, these results revealed clear variations in blender capacity, condensate output, temperature and compliance parameter to provide a comprehensive overview of the system’s operational characteristics. It gave valuable insights into daily conditions and confirmed the potential for performance improvements. Overall, the feasibility study established a solid foundation for redesigning the condensate recovery system to improve efficiency and effectiveness.

The simulation results demonstrated clear improvements in the system’s performance. The optimized design significantly reduced pressure drops across the network, which translates to lower pumping energy requirements. Flow rates were more evenly balanced, ensuring all sections of the system received adequate supply without overloading any individual component.

Data collected from the simulations confirmed that the redesigned system would operate more efficiently than the current configuration. Key improvements include:

Overall, the use of Pipe Flow Expert software proved invaluable in optimizing the condensate water recovery system. Figure 4 shows the simulations of the new layout design, that verifies the proposed modifications would deliver a more efficient, reliable, and cost-effective solution. It supports the project’s goal of improving system performance and reducing operational costs.

In addition, multiple operating scenarios were tested to evaluate system performance. These simulations identified potential issues and improvement areas, ensuring the design is both robust and efficient prior to implementation. The design principles are as follows:

This approach ensures that the new design is fully evaluated and optimized before actual deployment, thereby increasing the reliability and efficiency of the condensate water recovery system. The sample of simulations results are as illustrated in Figure 5 .

The simulation provided a detailed analysis of the redesigned system, covering flow rates, pressure profiles, pressure drops, friction losses, velocities, and overall efficiency. For example:

The analysis confirmed that pressure drops remained within acceptable limits, with no adverse impact on system performance. Flow rates and velocities aligned with design specifications, ensuring effective fluid transport. Furthermore, the low friction losses demonstrated that the redesigned network successfully minimized energy wastage, improving overall system efficiency. The simulation results validated that the redesigned condensate water recovery system meets performance targets. The new layout improves efficiency, reduces energy losses, and maintains stable operating conditions, while also highlighting potential areas for refinement before implementation.

The Festo Fluidsim model verified the reliability of the automated control system, as shown in Figure 6 and Figure 7 respectively. The simulation showed two clear operating states:

1) The condensate tank filled until a set water level was reached.

2) Once the threshold was met, valves opened, and the pump transferred condensate to the deaerator.

This control strategy proved effective in ensuring continuous operation without manual intervention. It also prevented risks such as overflow or underfeeding of the deaerator.

The energy savings due to recovered heat were calculated using the following relationship:

Energy saving = Q recovered × (1/η boiler) (1)

where Q recovered is the amount of heat recovered and η boiler is the boiler efficiency. This expression quantifies the reduction in additional energy required by the boiler to generate steam. It highlights the efficiency improvement achieved through condensate recovery.

To demonstrate this effect, a simple enthalpy balance was performed. Heating 1 kg of condensate at 95˚C to the boiler operating condition of 110˚C requires approximately 62 kJ. In contrast, heating 1 kg of fresh make-up water from 30˚C to 110˚C requires about 293 kJ, based on standard steam table properties. This comparison shows that using recovered condensate reduces the heating energy demand by nearly 80%. When scaled to the plant’s daily condensate flow, the saving translates into an overall ~30% reduction in energy consumption, consistent with industry-reported values.

The corresponding monetary savings can be expressed as:

C recovered = Energy saving × C energy (2)

where C energy is the cost of energy per unit. By applying this relation, the energy savings are directly translated into economic terms. This confirms that recovered condensate not only improves thermal efficiency but also yields substantial reductions in operating costs.

The system’s performance was evaluated based on actual plant data and cost analysis. Table 2 summarizes the savings achieved.

These results confirm that condensate recovery reduces fuel use, improves boiler efficiency, and lowers operating costs. The environmental benefits are also significant, with reduced emissions of CO₂, NOx, and SOx, contributing to improved workplace safety and sustainability.

The combined experimental and simulation results highlight several important benefits of the redesigned condensate recovery system. One of the most significant improvements is efficiency: by returning condensate at higher temperatures, the energy required for reheating in the boiler is reduced. This directly translates into lower fuel and water consumption, making the system more cost-effective and allowing for a short payback period. Reliability is also enhanced through automated control, which minimizes the need for manual intervention and ensures stable, consistent operation. In addition, the system contributes to sustainability goals by reducing both emissions and water wastage, aligning with broader environmental targets across the industry. Overall, the redesigned condensate recovery system effectively addresses the limitations of the previous configuration and delivers measurable gains in efficiency, cost savings, and environmental performance.