IMPROVING HEAT EXCHANGER EFFICIENCYTHE IMPORTANCE OF PROPERLY MAINTAINEDHEAT EXCHANGER SYSTEMS

Industries that rely on heat transfer equipment must always look to control the rising costs of fuel. One way to keep fuel costs at a minimum is to ensure that heat exchanger equipment is running at peak efficiency all the time.

THE PROBLEMThe number one problem heat exchangers face is caused by interior (TUBE) and exterior (SHELL) surface fouling. While the type of fouling can vary between exchangers, the consequences are common… increased operating cost and lost profits.

Because of their efficient use of energy to BTU ratios, tube bundles have become one of the most popular heat exchanger systems in use today, and one of the most difficult to maintain. Tube bundles have a tremendous amount of internal and external surface area, and when those surfaces remain clean, they exchange heat more efficiently. However, a bundle that is not clean uses more fuel and exchanges less heat in the process, resulting in lower output at greater expense.

THE CLEANING PROCESSESOver the years, many cleaning processes have been used to clean the tube and the shell sides of exchanger bundles. And while each have their place, some processes are much more efficient, safer and faster. Safety is the number one priority in any industry and any cleaning process. For industries that must take equipment off line to have it cleaned, “faster” is very crucial. Very often, the ability to return equipment to service quicker can mean tremendous increased profits to the bottom line and in the same line reducing the risk to the employees involved in the cleaning process. This drive for safer technologies has companies like HydroChem introducing advanced automation tooling, resulting in even faster cleaning, repetitive and efficient cleaning processes, while eliminating safety risks and hazards to the employees involved in the cleaning process.

EXPERIENCE COUNTSBecause of the potential for costly delays, there isn’t a lot of upside to choosing a industrial cleaning provider with limited experience or limited equipment redundancies in place. Sending a narrow shaft of steel, turning at high speed, pumping high pressure water into a tight space that you can’t see, is not a task that is without it’s share of unplanned events. Proper planning with the industrial cleaning provider is critical in successful cleaning projects. When those unplanned events happen, make sure your supplier isn’t sitting on their hands waiting. With proper up front joint planning make sure your industrial cleaning provider has redundant cleaning equipment is available immediately so down time can be greatly reduced. Through that proper joint pre-job planning, budget for redundant equipment and make sure your supplier has the ability to deliver the industrial cleaning service as well as the experience to know what could go wrong way before it does.

SHELL SIDE CLEANING The shell side of a bundle is extremely difficult to clean because of the buildup of debris that collects between tubes. This process cannot be done by hand held water blasting very effectively. You need specially designed equipment that can handle high volume and high pressure of water for the cleaning process.

In a typical shell side cleaning setup, bundles are taken off line and brought to a cleaning pad where remotely controlled blasting equipment forces high volumes of water at high pressures to reach deep into the spaces between tubes and remove various product buildup. Typical process times are 4-6 hours per shell side with automated equipment.

AUTOMATED SHELL SIDE BUNDLE CLEANING EQUIPMENTThe automated shell side machine used by HydroChem is one of the most efficient tools available for shell side cleaning. While this technology requires a larger footprint, it is very well suited for projects where there are multiple bundles that can be moved to and from a stationary blasting pad without too much trouble. Using dedicated sets of hydraulic rollers, multiple bundles can be set up and staged to be cleaned quickly. Hydraulic bundle rotation and programmable speeds allow for thorough and consistent cleaning results from bundle to bundle.

• Trailer or skid mounted• Volume: 200 GPM• Pressure: up to 20,000 PSI• Operation:

Manually operated by one individual.• Pump requirements:

475 HHP or 600 HHP pump • Safety:

Excellent. Operated from remote control platform.

PAD BLASTEROne of the newest tools on the market is the Pad Blaster from HydroChem. Originally designed to solve a specific customer’s need, the Pad Blaster has become very popular in various hand held hydroblasting applications. It’s small footprint, easy maneuverability, extreme versatility and lower operational cost have made the Pad Blaster the perfect tool in cases in many applications where hand held hydroblasting was used in the past. Most importantly, eliminating the hazards of hand held hydroblasting, this exclusive tool helps the operator maintains a close yet safe operational distance from the equipment being cleaned, allowing for better visual inspection and the use of higher horsepower for cleaning efficiency.

• Volume: 60 GPM• Pressure: up to 20,000 PSI• Operation: Manually operated by one

individual from within cab.• Pump requirements: Single 300 HHP pump • Safety: Excellent. Operated from within fully enclosed cab.

INTERIOR TUBE CLEANING PROCESSThere are two established methods for interior tube cleaning: Flex lancing and Rigid Lancing. The complexity of shell side cleaning pales in comparison to interior tube cleaning requirements that present far greater challenges. Not only do you need to get the interior of a tube clean to remove the effect of fouling, you need to do it in a way removes the hazards and eliminates the risks to the industrial cleaning personnel. Also, any damage to tubes, or damage the cleaning equipment would extend downtimes and delay the return of equipment to service.

CUSTOM SOLUTIONSNo bundle is too big to clean as evident by this massive shell side cleaning system designed to clean a 15 ft. diameter bundle and up to 100 feet long. Customizing a solution is a strength of Hy-droChem. Our team of engineers and specialists work months ahead of the actual job execution in planning, developing, designing, and fabricating these specialized solutions.

FLEX LANCINGWhile rigid lances are considered the most durable of tube cleaning systems, they have some limitations. They generally need a large footprint and are most cost efficient on large projects where numerous bundles are scheduled for cleaning. When tight quarters are a concern and/or moving bundles to and from a cleaning pad is not cost effective, flexible lancing is the only alternative.

One of the least expensive but most dangerous methods of cleaning smaller tube bundles is by hand. In this process an operator holds a flexible lance or wand that is pulled or pushed through the exchanger tube. Specifically designed tips use water jets to drag or pull the lance forward while simultaneously spinning the head to cut through debris. The lack of automated equipment reduces the overall equipment expense but the cleaning efficiency is dependant on the skill of the operator

operating the flexible lance. By slipping the flexible lance forward and pulling it back an operator can take an educated guess as to the cleanliness of the tube – no predictability in the cleaning process. Obviously, the more experienced the operator, the better, though by the use of camera inspections, you will see streaking or “candy striping” which confirms that overall results can be very inconsistent. Most importantly, hand lancing is the most dangerous activity any industrial cleaning company will complete.. The industrial cleaning company needs to take precautions to eliminate the potential of flex lances “hydraulicing” out of the exchanger, includes proper anti-withdrawal devices which can help reduce the risk of severe injury to the company’s employees.. Flex Lancing is also the most least efficient cleaning method as tremendous friction pressures are generated through the small flexible lances and loss of cleaning power at the end of the nozzles is developed.

DURAFLEXXX™ FLEX LANCINGIn 2009, HydroChem announced the design of a new tool, Duraflexxx™, that made flexible lancing as safe as rigid lancing and added a slew of other benefits. The Duraflexxx™ system is the most durable flex lancing system in the world. Since that time, Duraflexxx™ technology has grown from a single lance system, DX1, to two lances DX2 and finally to a triple lance system dubbed the DX3. In addition, the latest Duraflexxx™ AI series tooling adds the functionality of Automatic Indexing which is added to the consistent cleaning speeds of this system that creates a system that is extremely cost effective and as durable as it’s name implies. Bottom line with these specially designed machines you get flex lancing completed that has eliminated the risks/hazards of flexible lance cleaning and added consistent cleaning utilizing flexible lances.

RIGID LANCE SYSTEMSImproving the safety of tube cleaning has resulted in automation technologies that remove the operator from the line of fire and delivering more horsepower through the cleaning nozzles. Enter the rigid lance systems which are much more efficient than hand flex lancing systems. Rigid Lance Systems need much more room for the cleaning, equal at least the length of the exchanger to be cleaned.

DUAL RIGID LANCE AUTOMATIONThe most basic system is this dual rigid lance equipment which drives 2 steel lances at a time into the tube bundle, utilizing any type of water pressure up to 40,000 PSI. This system allows the operator to manually align the lances and then step a safe distance back from the bundle face to operate it. It also adds more precise control over drive speed while allowing for ultra high (40k) pressures to be used so the condition of the interior tube is not compromised. The result is both safer and faster than hand lancing delivering greater horsepower with water through the cleaning nozzles.

5 RIGID LANCE TUBE CLEANING SYSTEMLike it’s sibling shell side system, this rugged unit incorporates the use of remote operation and keeps the operator a safe distance away. In this case the operator sits in a comfortable control cab and manually operates a series of 5 rigid lances. By adjusting travel speed, water flow, water pressure and rotation with the addition of rotational cleaning nozzles, the operator can clean tubes with much greater speed, consistency and overall efficiency. In an typical configuration, this unit would sit near the shell side unit and create a complete tube/shell side cleaning solution.

STARS™ RIGID LANCE AUTOMATIONAt the top of the technology ladder is this high speed tube cleaning unit exclusively designed and built by HydroChem. STARS™ which stands for Synchronized Tooling and Robotic System incorporates the latest in computer technology to completely streamline the tube cleaning process. Using a proprietary guidance system, the bundle face is mapped and recorded into the computer. After the first set of tubes is lined up, the operator steps back and watches as the STARS™ system moves 5 sets of independently driven lances across the entire bundle face, jumping from tube to tube with impressive speed while each lance can rotate up to 200 RPM at pressures up to 40,000 PSI. The condition of each tube is recorded in a database that creates reports for current and future cleaning conditions and helps determine cleaning cycles for each specific bundle. Cleaning times for bundles have been cut in half compared to historical methods of rigid lance cleaning.

OTHER COMPONENTS OF SUCCESSFUL BUNDLE CLEANING

NOZZLE SELECTIONA key component of any water blaster operation is the nozzle and the choices are as varied as the surface fouling being removed. Having the nozzle specifically designed to deliver the maximum horsepower through the nozzle outlets is critical for maximizing the cleaning efficiency in hydroblasting. A company like HydroChem has many years of proven experience knowing which nozzle with get the job done with the most efficiency and carry a vast inventory of nozzles. Some, like their Wolverine High RPM nozzles are designed specifically for tube cleaning.

WOLVERINE HIGH RPM NOZZLEThe exclusive HydroChem designed nozzles come in two main categories, “Unpluggers” and “Polishers”. These nozzle designs are unique because they are designed to run at multiple pressures, and spin at unheard of speeds from an incredible 3,600 RPM up to a mind blowing 18,000 RPM. The cleaning efficiency of Wolverine High RPM Nozzles are multiplied significantly compared to conventional methods.

QUALITY ASSURANCE The last piece of the puzzle is proof that the job is done as your supplier promised. You can easily see the shell side of a bundle, but until recently you made a judgment on tube condition by peering into the first foot or two, watched some clean water come out the other end and hoped for the best, or even shined a flashlight at one end of the exchanger for visual inspection. Now with new technologies like the Micro Enhanced Video Inspection Tool currently in use by HydroChem, you can see the entire length of a tube and confirm that tubes are cleaned correctly. The video boroscope system is the only way to confirm that your tubes are cleaned thoroughly and that your exchanger is capable of operating at peak efficiency. Using this tool at the beginning of the cleaning to verify cleanliness levels with the customer is critical so cleanliness levels are determined up front and not at the end of the job, where time could be wasted on improper inspection criteria.

IRIS and EDDY INSPECTIONProperly cleaned bundles utilizing a system that has consistent cleaning capabilities will pass IRIS and EDDY inspections on the first pass and give you the confidence that equipment returned to service will be less costly to operate while offering increased BTU production. Without the use of bundle cleaning automation outlined herein for both the tubes and shell side, that objective will be very difficult to achieve.

At the end of the day, your goal should be to find the right supplier who can return your equipment to peak efficiency as safely and as quick as possible, while offering the piece of mind and documented proof that your project will be done to specification. The idea is to have a ZERO cost of cleaning as you reap the benefits for increased exchanger efficiency which has saved you in fuel consumption. With more than 70 years of turnaround experience, a world class team of project specialists, a global reach and the resources to support projects world wide, HydroChem should be considered the most logical choice for your next exchanger cleaning project.

www.HydroChem.com