It Boils Down to Control at Vietnamese Paper Plant

At the power boiler plant in Vietnam’s largest paper company, the boiler is absolutely critical to plant output. Thus problems with the company’s feedwater regulator system supplying water to the boiler demanded the reliable performance offered by a custom-designed CCI solution.

The pulp and paper plant’s existing feedwater regulator system consisted of a Masoneilan 78000 main valve and a Bailey startup valve; however, the plant was experiencing problems with flow control as the water transferred from the startup valve to the main valve. In addition, erosion in the two valves made it difficult for the customer to control the boiler drum level.

CCI’s solution was to replace the two problematic valves with a single 4-inch (100-mm) DRAG® feedwater control valve. This valve not only provides the full flow range demanded by the process, but combining the customer’s two valves into one will also eliminate the difficulties associated with the unstable transfer point.

CCI custom designed the valve trim to provide velocity control for the full range of valve travel. For instance, when the boiler is at full load, there is maximum flow and minimum pressure drop, so CCI designed the valve trim with just two stages at the top. When the valve starts up, however, there is a large pressure drop, which contributes to the erosion plant had encountered. To eliminate this problem, CCI customized the characterized trim to have 12 pressure-reducing stages during startup conditions. Each of these 12 stages will lower the pressure of flow through the valve so it will operate at a controlled, predetermined velocity. The CCI solution also boasts a longer stroke length, which will provide better resolution and improve flow control to the boiler.

By solving the customer’s flow control and erosion problems, the new CCI valve will improve overall control of the feedwater regulator system, which translates into a longer lifetime for the valve with increased reliability that will save the plant the cost of maintenance or unplanned shutdowns. In addition, better control of the feedwater regulator system will boost the reliability of the boiler system, which is critical to the entire pulp and paper plant. CCI’s solution will offer invaluable peace of mind as it ensures dependable plant output.

Published in SOLUTIONS Fall 20004