Controlling Steam Temperatures: A Game-Changer for Pulp Mills

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Pulp mills are heavily dependent on superheated steam for vital operations like drying, heating, and turbine power generation.

However, the temperature fluctuations of the steam can decrease operational efficiency or wreak havoc on pulp mill equipment in the event of improper design details or installation of the device, sensors and piping layout.

Proper desuperheater selection is crucial to effectively regulating the temperature of superheated steam and for maintaining the smooth and efficient operation of your plant. Improper selection can result in catastrophic equipment failures, disruptive downtime, and unnecessary repair costs.

A Canadian Pulp and Paper Mill struggled with controlling steam temperatures at their plant. Their system operated at two different steam conditions, 11.4 bar (165 psig) and 5.5 bar (80 psig). With a steam turbine also operating on site, the plant experienced significant load differentials that were triggered based on whether the steam turbine was online or offline. The table below highlights the load differentials of the 11.4 bar system.

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The desuperheater utilized by the plant caused several issues. Temperature control varied significantly, spray-water control had to be manually adjusted, and the unit required servicing every year - resulting in a costly and disruptive annual affair. With the 11.4 bar system being the more critical of the two, the plant supervisor desired to have the desuperheater changed. Through a consultation with Armour Valve, the exclusive distributor for Hora products in Canada, the plant decided on a Hora Multi Nozzle Desuperheater (MNSD) because of its design and durability in service. The pulp mill also wanted a solution that could handle the rangeability of their steam turbine.

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Hora Multi Nozzle Desuperheaters use a lance to transport water to the nozzles located in the center of the steam pipe. The nozzles are controlled by a piston stroke, eliminating the need for a separate injection control valve. Different nozzle sizes are available to accommodate varying load conditions, ensuring a high rangeability and uniform atomization across the entire flow range. The use of pressure swirl nozzles creates a rotational movement of the cooling water, further enhancing atomization. The desuperheaters are made from high-quality forged solid material to avoid weld seams on the pressure bearing body. Additionally, a dirt catcher with a fine sieve is installed to minimize the risk of clogging. The design and material selection enable efficient and reliable operation even at higher differential pressures and temperatures.

Response from the pulp mill was overwhelmingly positive, as the MNSD successfully controlled steam temperatures at a mere 5ºC above saturation, with absolutely no servicing requirements for three years. Impressed by the results, the plant considered replacing their low-pressure system desuperheater units with HORA products.

The selection of the right desuperheater and engineering expertise proves to be paramount in maintaining efficient and smooth plant operations while mitigating risks associated with temperature fluctuations. The pulp mill achieved enhanced performance, cost savings, and improved operational reliability, reaffirming the critical role of proper desuperheater selection.

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About Amour Valve

Armour Valve is a Canadian specialty valve, piping and process equipment sales and service organization. Family-owned and purpose-driven, we exist to transform infrastructure for a healthy, thriving planet. We specialize in providing severe service solutions for high-pressure, high-temperature, high-cycle, abrasive, erosive, and corrosive applications.

Visit booth# 27 during the PACWEST conference in Whistler, BC to learn more about the Hora Desuperheater and our other product solutions for pulp and paper facilities.

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Author Bio

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Niloufar Baniassadi, Pulp & Paper Market Lead

Niloufar Baniassadi is responsible for overseeing Pulp & Paper market business development in her current role as Pulp & Paper Market Lead at Armour Valve. Equipped with a degree in Electrical Engineering, she has 15 years of experience in international technical sales and is committed to customer success.