| Cutting edge cleaning | | | | in a tube and pipe environment from 2mm |
| Mike Watson of Tube Tech International, | | | | to upwards of 1m, equipment is modified |
| UK , explains the advantages of new heat | | | | to suit the consistency of deposit and |
| exchanger and pipe cleaning techniques | | | | pipe configuration. A wider variety of |
| over traditional methods. (as featured | | | | deposits can be removed by an innovative |
| in Hydrocarbon Engineering magazine) | | | | drift system loaded into large diameter |
| A five day shut down had been planned at | | | | pipes through a very small aperture |
| an oil refinery to accommodate | | | | which then expands to suit the diameter. |
| traditional pressure jetting and | | | | It also has the ability to return back |
| chemical cleaning methods to clean four | | | | down the same line without creating an |
| crude train heat exchangers. | | | | expensive loop system. |
| Tube Tech challenged this route using an | | | | Aluminium tubes |
| alternative innovative method to | | | | The scale which builds up in aluminium |
| overcome the main disadvantages: | | | | furfural exchangers is notorious for |
| Difficult to clean with lengthy downtime | | | | being highly tenacious. The accepted |
| leading to expensive lost production. | | | | wisdom has been that due to their |
| The company was able to clean each | | | | delicate nature, aluminium hairpin heat |
| bundle in a few hours without chemicals | | | | exchangers can only be cleaned using |
| or high pressure water jetting, while | | | | 200bar (3625 psi) bar water pressure. |
| the other three exchangers were kept | | | | This low-pressure approach only removes |
| running to maintain continuity of | | | | 20% of blockages and scale with the |
| production, effectively 'flat lining' | | | | additional problem that it tends to |
| the production output. The cleaning | | | | compact coke deposits on the U bends |
| procedure delivered a substantial Kj | | | | rather than remove them. |
| C-hr improvement on just one bundle | | | | Working with clients sample tubes, Tube |
| compared to all four bundles previously | | | | Tech's research and development team |
| cleaned with either of the traditional | | | | devised a combined mechanical and water |
| procedures. | | | | jet system which used 2500 bar ( |
| Cleaning technology | | | | 40,000psi) to remove coke deposits and |
| There has been little change over the | | | | improve overall cleanliness to 90%. |
| decades in the methods and equipment | | | | The three-stage process included a |
| used to clean and de-scale heat | | | | sensitive mechanical hairpin-cleaning |
| exchangers and pipelines. The low-tech | | | | device coupled with exceptionally low |
| approach of high pressure water jetting | | | | volumes of water. First, each tube was |
| has kept it as a low skilled job with | | | | cleaned using the Softdrill™ lance |
| largely unimpressive and variable | | | | made from 'intelligent' metals to |
| results. | | | | prevent damage to the tube wall. These |
| Despite being armed with demonstrable | | | | soften on entering the U-tube and |
| evidence of being able to achieve better | | | | stiffen on extraction, while an |
| results than traditional methods, the | | | | oscillating motion drills the blockage |
| company has faced an up hill struggle to | | | | using a mixture of water and an |
| get its innovative techniques widely | | | | occasional infusion of food grade media |
| accepted. | | | | at 12 * the pressure and four times the |
| It has not been easy persuading | | | | speed of the conventional approach. |
| potential clients to consider trialling | | | | Finally, a micro turbine rotating under |
| new techniques designed to improve | | | | controlled hydraulic pressure was guided |
| substantially on traditional water | | | | through each tube. |
| jetting methods. | | | | Not only were the results substantially |
| There has even been outright scepticism | | | | improved but also cleaning was carried |
| that Tube Tech's claims can be | | | | out in-situ, reducing downtime by 200% |
| substantiated. Persistence and | | | | and avoiding possible handling damage, |
| determination were needed to change the | | | | the cost of cranage and bundle pulling |
| industry mind set regarding the | | | | equipment. |
| effectiveness of current cleaning | | | | A U-bend first |
| methods. | | | | The inability of traditional water |
| Long-term maintenance contracts can also | | | | jetting to remove hard coke and oily |
| act as a barrier to an investigation of | | | | sludge in the U bends in heat exchangers |
| the company's advances. | | | | in crude oil distillation complex has |
| The historical reliance on low tech, low | | | | produced a 70% cleaning standard. |
| skill water jetting for pipe cleaning | | | | After analysing the nature and |
| has meant that clients have accepted | | | | composition of the deposit and its |
| that this is the best that can be | | | | dimensions, the Tube Tech approach was |
| achieved. | | | | used. The result was: |
| This meant that there was often no | | | | • 99% of contamination removed. |
| quantifiable data against which Tube | | | | • Hairpins cleaned for the first time |
| Tech's improved results could be | | | | ever. |
| measured. | | | | • Heat exchangers returned to |
| Setting out to devise a more scientific | | | | virtually as new condition. |
| approach to the whole cleaning and | | | | • Cleaning operation completed in |
| de-scaling process, | | | | three times faster than the standard |
| The company has created more than 40 | | | | pressure jetting times, down from six to |
| innovative techniques. This has led to | | | | two days. |
| several 'firsts' in heat exchanger and | | | | • Greatly improved throughput. |
| pipeline cleaning processes. These | | | | In-situ cleaning |
| developments include: | | | | Solving problems related to specific |
| • The ability to clean exchangers | | | | equipment often enables the company to |
| in-situ where previously they were | | | | further improve on its initial |
| pulled. | | | | performance. The cleaning process for an |
| • The ability to clean and unblock | | | | important tube bundle |
| hairpin bends. | | | | In a catalytic cracker was initially |
| • Speed cleaning difficult bundles in | | | | reduced from nine days to six but this |
| hours instead of days. | | | | first experience subsequently lowered |
| • Online cleaning of difficult heat | | | | the barriers further. A smaller sister |
| exchangers. | | | | unit was subsequently cleaning in three |
| The introduction of more sophisticated | | | | hours instead of three days. |
| technology enables the cleaning and | | | | For the first time the operation was |
| de-scaling to be carried out faster so | | | | carried out in-situ, using a new turbine |
| there is considerably less downtime, and | | | | method, incorporating a low-pressure |
| potential mechanical damage to equipment | | | | water jetting system avoiding the cost |
| is eliminated. Less waste, dry processes | | | | and effort of removing 10t of exchanger |
| and the elimination of chemicals | | | | gaskets, scaffolding or cranes. |
| provides a safer and more | | | | In-situ cleaning lengthens the life of |
| environmentally acceptable process. | | | | the bundles, which deteriorate through |
| The company has also taken traditional | | | | damage caused when they are removed for |
| pigging methods and tailored them to | | | | cleaning. |
| achieve much better results. Operating | | | | |