Kimberly Clark Mexico operates many tissue mills in Mexico; one of them is located in Orizaba. As phase I of a major machine rebuild, KCM decided to replace one of their Yankee steam cylinders and simultaneously install a new state-of-the-art Yankee hood, process air systems and full heat recovery systems.
Enerquin was invited to submit a proposal for the new Yankee hood. In the preparation process, the Enerquin technical service team went on-site shortly after to evaluate the existing Yankee hood operation. Field adjustments were made to temporarily optimize the thermal efficiency while awaiting the new equipment. The Enerquin team performed a full analysis and collected all the necessary information required to calculate the expected savings associated with the proposed new Yankee hood and associated heat recovery unit. Although new Yankee cylinder offers came complete with a new Yankee hood, the Enerquin proposal finally won the favours of KCM. The Enerquin package included a complete high-temperature and high-velocity Yankee hood with process air systems and combustion/make-up air heat recovery equipment.
The design phase was completed at the Montreal Head Office while fabrication of the equipment (Yankee hood, combustion chamber, heat exchangers etc.) was completed at the Enerquin manufacturing plant located in Cowansville, QC, where all Enerquin Yankee hoods have been manufactured for the last 25 years.
The new DUO process air system consisted of two complete air systems including two larger supply fans, one exhaust fan, two burners c/w combustion chambers and associated heat recovery units. One of the main challenges consisted in fitting all new equipment on the existing mezzanine originally designed for a MONO system. Enerquin’s final equipment layout, although very compact, provided good access to all components both for the operation and the maintenance personnel.
The new DUO air systems were designed to initially operate as “Parallel” systems i.e. each hood half has its own independent air system; the parallel mode made it easier for the operators to start up with the new system. Enerquin had built in the necessary components to switch from the “Parallel” to a “Cascading” mode of operation as soon as production would reach some stability. The “Cascading” mode further improves the thermal efficiency (TE) by diverting the dry end hood exhaust air to the inlet of the wet end circulation fan to act as make-up air while 100% of the exhaust is now bled from the wet end hood.
The installation phase was completed smoothly with commissioning and start-up following shortly after. Preliminary readings after start-up led to excellent hood thermal efficiency values ranging from 1800 to 1900 BTU/lb. H2O evaporated when compared to the “Good” benchmark for the industry which is 2000 BTU/lb. H2O evaporated by the hood. After only a few months of operation, the process air system was switched to the Cascading mode; once optimized again by the Enerquin technical service team, closely assisted by the KCM operators, this new setup led to hood thermal efficiency ranging from 1500 to 1600 BTU / lb. H2O evaporated which exceeded expected performances.
Consequently, the mill experienced a production increase with substantial energy savings.
- Parallel mode: 1800 to 1900 BTU / lb. H2O evaporated
- Cascading mode: 1600 to 1700 BTU / lb. H2O evaporated
Operating with state-of-the-art equipment will win half the battle on the way to an energy-efficient operation. Optimizing the air systems is crucial if you want to reach the most efficient operation. This will require an initial in-depth air system study to understand and fine-tune all the various operating parameters and settings. Also, proper training of the operators to maintain the optimized operating conditions for the months to follow is key.
Kimberly-Clark de México, S.A.B. de C.V. (KCM) manufactures and markets a wide array of paper-based products which are used by millions of Mexican consumers: disposable diapers, feminine-care pads, bathroom and facial tissue, napkins, kitchen towels, hand towels and more.