In heavy industries such as manufacturing, chemicals processing, and oil and gas, cooling systems using water, cooling towers and other kinds of equipment to repel heat generated in various processes and plants. Ensuring cooling systems solutions are effective and optimised are integral to business operations.
In oil and gas, there are a variety of cooling systems used. Evaluating the efficacy of cooling systems involves understanding how individual components such as cooling towers, pumps, fans and nozzles work together with measurements and indicators such as flow rates, temperatures, pressure drops, drift losses and evaporative losses. By focusing on the entire system rather than on individual components, inefficiencies and energy losses may be avoided.
To establish if efficiency increases in a cooling system are possible, one must first understand the various types of systems and their respective strengths and weaknesses. Cooling systems come in a variety of designs and constructions, each with its own set of pros and cons.
All cooling systems are generally open or closed systems, with a once-through or recirculated design wherein a main coolant is returned to the source or recycled. A direct cooling system may have one or both of these design characteristics, whereas an indirect cooling system may incorporate both.
Systems that are either direct or indirect are also referred to as main or secondary systems. These terms are used to distinguish between systems in which heat is discharged to the environment or to a secondary media.
Direct systems consist of just a heat exchanger or cooling tower, process medium, and a coolant. Indirect systems use at least two heat exchangers and a closed secondary coolant and are commonly used in nuclear plants where leakage must be avoided.
In direct systems, wet designs commonly use cooling towers as specialised heat exchangers that cool water by exposing it to air. Water that has been heated is pushed through the cooling tower. The water sprays through nozzles onto heat transfer material to expose as much water surface area as possible to the air for evaporation which creates the cooling action. The cooled water is then returned to the process equipment to absorb heat. It is then pumped back to the cooling tower where it will be cooled once again.
Dry cooling systems using air flow are used when water is scarce or unavailable. Air-cooled heat exchangers are designed to withstand the high heat loads seen in oil and gas and chemical processes and are low maintenance. They cannot, however, chill water or process fluids to temperatures as low as wet cooling towers. They also do not generate the vapour plume associated with evaporative cooling towers.
Operators must comply with environmental standards that restrict the use of hydrocarbons, water, and drift rates which can be a challenge for ageing equipment or older evaporative cooling towers. Replacing, repairing or maintaining ageing cooling towers must be completed during planned outages, often needing to engage temporary cooling tower rental services. Operators should only use qualified providers such as EXS Synergy which offers comprehensive cooling systems solutions including cooling tower rental services.
Cooling systems should ultimately be made with durable materials and well maintained by reputable and qualified technicians and engineers. Cooling systems must also be integrated into comprehensive maintenance programmes to optimise the lifespan of this vital equipment and components.
