Inspection, Surface Prep and Non-destructive Testing
Are you in the oil & gas industry? Are you involved in non-destructive testing, inspection, or surface preparation? How about maintenance of pipelines, heat exchangers, or pressure vessels? If you deal with these or similar operations, proper cleaning of surfaces might well be a process you regularly undertake.
Cleaning Delicate Equipment Safely
What is the best way to clean surfaces of such equipment? While there is no one best way for every circumstance, dry ice cleaning is a state-of-the-art method that can save time and money. It uses recycled CO2 in the form of solid dry ice particles as the cleaning media. Dry ice is soft and non-abrasive to most surfaces and can thus be used around delicate components, including electronics, that would be damaged by water or solvents. As the blasting equipment is portable it can be used in place, thus minimizing disassembly and other preparation time. Lastly, dry ice turns to a gas after contact with the surface being cleaned — cleanup time is rock bottom minimum, there is nothing to dispose of, contamination of moving parts is not an issue.
To begin, let’s establish what exactly we’re talking about when we say “biodiesel.” ASTM (American Society for Testing and Materials) has published a standard, D6751-07b, that defines what biodiesel is. We’re not talking about used cooking grease, or even commercially produced biodiesel, if it doesn’t meet this standard.
Also, the word “biodiesel” is often used to describe what is actually a blend of biodiesel and diesel fuel. (The diesel fuel sold for on-road use in the U.S. is Ultra Low Sulfur Diesel fuel, or ULSD.) The term “BX” designates the blend ratio, where “X” stands for the percentage of biodiesel in the blend. So B100 means 100%, or pure, biodiesel, while B20 means 20% biodiesel mixed with 80% ULSD.
Additionally, this article doesn’t address OEM recommendations or warranty limitations. We’re simply looking at the question from a mechanical standpoint.
So now, with all that out of the way, what’s the bottom line?
Here are a couple of snags that can show up in any diesel engine when using biodiesel:
Fuel filters may initially clog:
This applies to engines that have burned petroleum diesel for years before switching to biodiesel. Over time, petroleum diesel leaves small carbon and tar deposits in a fuel system. B100, a mild solvent, will “clean out” the fuel system, dislodging these deposits. This is a good thing, but it’s inconvenient when a fuel filter clogs with these deposits. Once the fuel system is clean (usually after burning 1-2 tanks of B100), this issue goes away. B20 and lesser blends do not have this cleaning effect.
Biodiesel begins to gel at a higher temperature than ULSD. As a general rule of thumb, the greater the percentage of biodiesel present in a blend, the higher the temperature at which it will start to form wax crystals too large to pass through the fuel filter. In extreme cold, without a fuel preheating system, all but the most dilute biodiesel blends may be impractical.
Now, let’s discuss changes in diesel engine technology.
Pre-common rail diesel engines (mostly pre-2000)
These engines work very well with B100 (as well as with lesser blends). In fact, biodiesel is often a superior fuel for these engines. It is a far better lubricant than ULSD, sharply reducing injection pump wear. Unlike ULSD, which is made up solely of hydrocarbon chains, biodiesel molecules also contain oxygen. This oxygen contributes to better combustion. Thus, even though biodiesel has a lower energy content than ULSD, some engines may actually see a slight increase in power output, with minimal loss of fuel economy when using biodiesel.
Common rail diesel engines
Rule of thumb:
Any biodiesel blend works great.
Diesel engines with common rail injection systems started showing up in the early 2000s. These systems burn ULSD more efficiently than older systems, so biodiesel’s oxygen content no longer offers any real efficiency advantage, and its lower energy content manifests itself in a slight reduction in fuel economy and power. Further, high precision common rail injection systems are “tuned” to fuel of a given viscosity, and the viscosity of B100 differs significantly from that of ULSD. This may, for example, change the spray pattern of fuel into the combustion chamber, and the end result can be an increase in soot and carbon buildup.
Engines with diesel particulate filters
Rule of thumb:
While B100 works, these engines work best with lower blends, like B20.
In 2008, the EPA started phasing in its Tier IV diesel emissions standard, which required an immediate 90% reduction in particulate matter. Diesel particulate filters, or DPFs, are exactly what they sound like – a filter in the exhaust system that captures particulate matter, such as soot. To regenerate, or clean, the filter, atomized ULSD is injected into the exhaust. When it reaches the DPF, it ignites and burns off the particulates that have collected there. To accomplish this, many engines periodically inject ULSD into the cylinder during the exhaust stroke. This ULSD vaporizes and flows through the exhaust system with the other exhaust gases. Biodiesel, however, is less volatile than ULSD. When it is injected into the cylinder during the exhaust stroke, rather than flowing out through the exhaust valve as a vapor, some of it condenses on the cylinder walls as a liquid and runs down through the crankcase. Over time, this biodiesel accumulates and dilutes the engine oil. Thus, for engines equipped with this style of DPF regeneration, biodiesel blends generally should not exceed B20.
Some DPF systems are able to eliminate this problem by using an extra injector located in the exhaust system to handle regeneration. Such configurations don’t cause engine oil dilution and so are compatible with B100, but they are also less common.
Rule of thumb:
B20 works with DPF-equipped diesel engines. Higher blends work with some engines with specific configurations for DPF regeneration.
Complications associated with using B100 may vary from negligible to major, depending on the engine configuration and the operating environment. B20 and lower blends, on the other hand, present minimal complications when used in any modern diesel engine and in all but the coldest operating environments.
Diesel Generator Rentals
Red-D-Arc carries diesel
and natural gas
generators in a range of sizes. D&D Power
provides full service oilfield generator rentals including generator paralleling
Red-D-Arc was featured in the December/January issue of Tank Storage Magazine in an editorial titled “Rental welding equipment for storage tank fabricators”. Tank Storage Magazine is an industry leading publication, reporting exclusively on the bulk liquid tank storage and terminal sector.
The storage tank construction industry is highly competitive and fabricators gain a significant advantage by leveraging Red-D-Arc’s rental fleet of automatic tank welding equipment. Red-D-Arc supplies specialized automatic storage tank welding equipment to companies in the tank fabrication industry for projects all over the world.
Along with our specialized tank welding equipment comes a highly knowledgeable and experienced team of Red-D-Arc technicians. Sayer Hendricks – storage tank welding equipment specialist at Red-D-Arc is quoted in the article: “A fabrication company without prior knowledge of the equipment, is able to rent a turn-key tank welding automation system and increase their welding productivity by 40-50%. With on-site training, service and support, our customers are up and running quickly and making 100% x-ray quality welds without fail”
The full article is available here: Rental welding equipment for storage tank fabricators
By guest Blogger Katarzyna K.
Katarzyna has an Msc in Materials Science and has worked in the oil and gas industry in jobs related to hydraulics, welding and the retrofitting of oil rigs.
Stainless steel is used extensively in the petrochemical industry due to its high resistance to severe conditions. When welding inox steels, the smallest details matter and have an impact on weld quality. The following are some tips for stainless steel pipe welding based on my oil rig repair experience:
During an oil rig repair project that involved 2205 duplex stainless steel pipe TIG welding, we could not achieve the required weld properties. Despite using the recommended filler metal with higher nickel content, compared to the base metal, and controlling the interpass temperature, the weld tensile strength was still too low. In order to reach the required weld quality we dug deeper and found a solution – (more…)
An oilfield equipment and vessel manufacturer in the United Arab Emirates approached Red-D-Arc for assistance with a large project. It was awarded to them at the last minute and was not their primary area of expertise. The requirement was to manufacture 25 large tanks with a timeframe of only one year. Each of the tanks was to be 5 meters in diameter by 25 meters long, manufactured using 16 millimeter thick material at a weight of approximately 45 tonnes.
The experienced Red-D-Arc Weld Automation team was able to immediately address all of the customer’s challenges. While other suppliers where insistent that the customer purchase the equipment, Red-D-Arc determined that long term rental would be their best option. This would avoid the time consuming process of acquiring CAPEX approval to purchase such a large amount of equipment and would further increase the profitability of the project. The manufacturer also had questions on how to avoid ovality and transverse movement of the sub-assemblies. Red-D-Arc experts were on-hand to provide the right advice and the right equipment to address these challenges.
The rental equipment included:
• 6x 10 tonne turning roll sets
• 10x 60 tonne drive rolls
• 47x 30 tonne and 60 tonne idler rolls
• 7x submerged arc packages with LT7 tractors and DC600 power sources
Red-D-Arc worked very closely with the company to ensure their success, providing comprehensive training and on-site assistance. After the successful completion of this project the company has become recognized in their market and are receiving new orders from similar customers in the industry. Furthermore, they anticipate being awarded “phase 2” of this project which is scheduled to begin in 2018.