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Tag Archive: Oil Coolers

  1. The causes of overheating and how to avoid them

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    After leaks, overheating is the most common concern for people working with hydraulic equipment. An overheated system can reduce the effectiveness and life span of oils in the system, and can degrade important polymer elements, like hoses and seals, Hydraproducts explained.

    While most people who work with hydraulic systems know that overheating is bad, few fully understand the causes of this concern. It can be hard to find a solution to an overheating problem, and even more difficult to uncover the exact cause.

    Defining overheating

    Generally speaking, an overheated system is one that’s running at 180 degrees Fahrenheit or hotter, according to Machinery Lubrication Magazine. However, every system is unique. It’s important to monitor the viscosity of your oil as well as your equipment temperature to determine whether it’s overheating.

    “An overheated system is one that’s running at 180 degrees Fahrenheit or hotter.”

    The ability to identify overheating right away is a crucial skill, but it’s preferable to avoid the issue altogether. The only way to avoid overheating, by definition, is to ensure that the amount of heat your system is generating is less than the amount it’s dissipating.

    Determining your system’s limitations

    The first step in avoiding overheating is knowing your system’s capacity. Machinery Lubrication Magazine explained this can be done with a simple equation using the system’s continuous input power and its efficiency percentage.

    The example provided by the source used a system that has a continuous input power of 100 kilowatts and an efficiency of 80 percent. In this case, the system needs to be able to dissipate at least 20 kilowatts at any given time.

    Any time circumstances reduce the system’s ability to cool or dissipate heat, or increase the heat load above 20 kilowatts, overheating will occur. Given these facts, there are two ways to correct an overheating problem: Decrease the heat load, or increase the heat dissipation.

    Decreasing heat load

    If your system is overheating, there’s an underlying cause that may not always be immediately evident. The best way to avoid increasing heat loads is to ensure that every feature of your system – from the machines to the oil and seals within them – is in top condition.

    Change out parts and fluids when they begin to degrade or otherwise go bad. Perform routine inspections to make sure you catch issues before they become operations-halting problems. Keep a regular maintenance and cleaning schedule as well.

    Sometimes it’s not a buildup of debris or a skipped cleaning that causes overheating. Any leaks in your hydraulic system can have a negative effect on your operation as a whole.

    “If your system is overheating, there’s an underlying cause.”

    The main goal here is to ensure that your equipment is operating efficiently at all times. When your system is operating as it should, there are fewer chances for it to overheat.

    Increasing cooling capacity

    If everything seems to be consistently in order, but you’re still having trouble with overheating, it’s a sign that your system needs an adjustment. Your cooling system could be worn out. Be sure to regularly check all cooling system parts and their functionality so you know when to replace something.

    Sometimes, your cooling system may just not have the right capacity for your hydraulic machinery. Don’t let this problem persist. One way to increase the dissipation rate is to add another oil cooler, Engineering Made Easy pointed out. With an added cooler comes increased ability to cool the system down before the temperature swings too high.

    An overheated hydraulic system won’t do you, your business or your clients any favors. A major part of running an efficient operation is the ability to maintain the right temperature. Be sure you know the maximum heat your system can handle, and take steps to keep it in that range.

    Remember, one important part of maintaining an efficient system is knowing when to replace critical equipment and components. When you need to replace your shell and tube heat exchanger, or add an oil cooler, reach out to the experienced heat exchange engineers at Enerquip

  2. Shell and tube heat exchangers used for waste heat recovery

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    Waste heat recovery has been a topic of concern for large-scale industrial companies for several decades. Not only does recovering waste heat make an operation more environmentally friendly, but it also helps to cut costs. Additionally, it can reduce the amount of resources needed to power a facility.

    Many industries and facilities have implemented different methods of waste heat recovery. One popular choice is using a shell and tube heat exchanger. According to the Energy Efficiency Guide for Industry in Asia, these exchangers are best suited for recovery methods dealing with warming liquids with heat recovered from:

    1. Condensates from process steam, distillation processes or refrigeration, or air-conditioning systems
    2. Coolants from engines, lubricants, bearings, air compressors, furnace doors, pipes or grates
    3. Flue gas streams and exhaust streams from furnaces, dryers and exhaust stacks

    The waste heat usually flows shell side, while the liquid is positioned tube side. This is because the higher-pressure liquid or vapor should be in the tube, because the shell is the weaker container. Utility fluids and products being heated can also be kept cleaner on the tube side of a heat exchanger. Waste heat typically produces condensation. Allowing condensates to form on the inside of the tube will typically cause flow irregularities and could lead to problems with the exchanger.

    Vegetable oil processing plant

    One example of a shell and tube heat exchanger put into practice for recovering waste heat is outlined in Energy Mines and Resources Canada’s Energy Management Series for Industry Commerce and Institutions. The paper explained a vegetable oil processing plant hoped to reduce its use of a steam heater in the refining process. The semi-processed oil needs to be heated from 30 degrees Celsius to 80 degrees before heading to the final stage of processing and then storage.

    “A shell and tube heat exchanger for waste heat recovery saved a processing plant $29,570 a year.”

    When the oil is transferred to storage, some heat is expelled that the company wanted to recover. This heat would then be used to warm the oil before going to the steam heater, reducing the amount of energy needed to bring the oil to its optimum temperature. By sending the oil through the heat exchanger prior to going into the steam heater, the oil can be heated to 70 degrees Celsius, requiring the steam heater to only raise the temperature by 10 degrees instead of 50.

    By implementing this practice, it was predicted the processing plant could save $29,570 annually. Taking into consideration the cost of the exchanger and its installation, it would take slightly more than half a year to see financial benefits.

    Diesel engines

    Research done by Saiful Bari, a senior lecturer, and Shekh N. Hossain, a research student at the Barbara Hardy Institute, a division of the School of Engineering at the University of South Australia, showed shell and tube heat exchangers could also provide beneficial heat recovery methods for diesel engines.

    Bari and Hossain explained the exhaust from diesel engines contains 38 percent usable energy. Heat exchangers were fitted to connect to the engine’s exhaust and arranged in parallel and series configurations. The two exchangers had different purposes. One, called the super heater, was used to superheat steam coming from the exhaust, which normally expands in the truck’s turbines. The second, named the vapor generator, was used to generate vapor from a liquid put into the exchanger.

    The researchers found in initial testing that 16 percent of additional power was recovered. Knowing that the heat exchangers used were not built specifically for this application, they decided to customize them to more efficiently recover the heat. After optimization, 23.7 percent additional power was generated. They also found that maximum heat recovery could be achieved with both the series and parallel arrangements when the engine’s pressure is higher, specifically at 30-bar working pressure. With this pressure, up to 9.85 kilowatts of energy could be retrieved. With lower-pressure engines, the parallel configuration is more efficient than the series configuration because it produced a higher mass of steam.

    Bari and Hossain attributed the success of their research partially to the fact that they customized the design of the heat exchangers to the particular engine used. They noted that, by using these shell and tube heat exchangers for heat recovering, the efficiency of the engine rose from 30 percent to 41 percent.

    Both of these examples show that waste heat recovery can be used to save money and resources, as well as make processes more energy efficient. Many different industries can benefit from using shell and tube heat exchangers in this way.