Pump Maintenance Essential for the Chemical Processing Industry
Chemical processing plays an important role in many industries including the traditional chemical, petroleum, and petrochemical markets, as well as in operations for industrial gases, plastic producers, inorganic chemicals, paints and pigments, coatings, and detergent manufacturers.
The harsh, corrosive, and relentless operating conditions of chemical processing plants require tough and reliable equipment that runs 24/7/365. And while any equipment failure can be detrimental to the facility’s productivity and corresponding profitability, one of the most critical components in chemical processing is the transfer pump.
Transfer pumps in the chemical-processing industry must be able to handle the following operational conditions: shifting temperatures and humidity, incorrectly anchored piping, piping with inhibitive sharp bends, changes in type of product or its viscosity, high volume (50,000 gallons) and high flow rates (4,000 gpm), changes in product velocity and force, and changes in hydraulic operating point.
Because centrifugal pumps can operate in these challenging environments, they have been the preferred chemical processing pump type for decades. However, they must be properly maintained. Centrifugal pumps operate by using bladed impellers to transfer rotational mechanical energy to the fluid, increasing its kinetic energy or angular momentum while also increasing the fluid’s potential energy (static pressure). That kinetic energy is then converted into usable pressure energy in the discharge collector.
There are three main centrifugal pump styles:
ANSI – Meets the manufacturing criteria set by the American National Standards Institute (ANSI) in 1977. ANSI pumps are engineered for operational flexibility and durability; they can also be self-priming, in-line, end-suction, etc.
Standard End-Suction – Designed for the transfer of thin fluids, standard end-suction pumps are the top choice for water applications.
Self-Priming – Able to lift liquid, self-priming pumps are ideal for pumping when the source is below the centerline of the pump.
Proactive maintenance schedules are the best way to ensure that transfer pumps constantly achieve maximum efficiency and effectiveness while extending overall pump life. In addition to creating a quarterly and yearly maintenance schedule, facility operators should also keep a detailed record of preventive and reparative maintenance for each pump. This information can help diagnose and minimize future problems, and reduce the downtime of costly equipment.
- The proper quarterly maintenance for transfer pumps should include:
- Checking the structural soundness of the pump’s foundation and hold-down bolts.
- Changing the oil and greasing the bearings every three months or every 2,000 operating hours, whichever comes first.
- Checking the shaft alignment.
In addition, the annual maintenance should check and record the pump's performance in detail and measure that performance against benchmarks from the early stages of the pump’s operation.
Although scheduled checkups are important for keeping pumps running at their efficient best, routine maintenance and general awareness of the optimal condition for various pump parts can also help extend pump life.
Operators should routinely monitor the following:
- Bearing and lubricant condition – Bearing temperature should be consistent and lubricant should be clear with no signs of frothing.
- Shaft seal condition – Mechanical seals should show no signs of visible leakage.
- Overall pump vibration – Unwanted vibration can indicate a change in pump alignment, the presence of cavitation or resonances between the pump, its foundation or the valving located in the suction and/or discharge lines.
- Differential pressure – Gradual decrease in the developed head pressure of the pump can indicate that the impeller clearance has widened, requiring adjustment.
By following a regimented maintenance schedule and making daily maintenance checks part of chemical processing culture, facilities can save time and money. Chemical processing facilities with the savvy to stay ahead of maintenance problems will reap long-term benefits by reducing pump downtime, extending pump life, and creating a better working environment for facility personnel.