Frequently Asked Questions Regarding Venturi Technology for Steam System Condensate Removal
Q: Why does Enercon recommend venturi technology for condensate removal from a steam operating system versus the standard mechanical steam trap offerings?
A: Presently, a properly sized venturi assembly is the most efficient technology for complete removal of condensate from an operating steam system while minimizing any associated energy losses. An Enercon Venturi Unit is superior to mechanical steam trap technology on day one of installation and this performance gap only increases over time versus mechanical traps because unlike them there is no degradation in performance over time. The Enercon Venturi Unit’s single solid one-piece construction, with no moving parts, ensures it is operating effectively in year 20 exactly as it did on day 1.
That said, Enercon’s primary purpose is providing our clients with operational & energy efficient steam systems. If a new technology comes along that performs condensate removal more efficiently than venturi technology and is permanent, then Enercon will evaluate its potential and act accordingly.
Q: Why does Enercon start with a complete technical evaluation of a system before the sizing of an Enercon Venturi Unit?
A: The reason for performing a technical evaluation of a system is to ensure that the steam system is set up correctly. This evaluation is the basis for all future recommendations and corresponding actions.
Having a well-designed system not only assures the operational efficiency of a steam system but also lends creditability to the future data we collect on the system. Enercon’s initial steps involve discussion of the system with operational personnel, review of pertinent drawings, and inspecting the specified portion of the system from the boiler to the end of the line.
Some, but not all, of the items we review during our technical evaluation are:
- Equipment (& original manufacturer’s design for such)
- Control Sizes;
- Functionality of DeSuperheaters;
- Are pumps required?
- Correctness of steam piping, indoor vs. outdoor systems, environmental issues such as temperature and humidity, etc;
- Trap spacing, trap locations, if on equipment, how and where installed.
- Condensate return system – piping design, how and where is it returned to, design pressure, distance, elevation, etc.
- Again, these are just some of the factors we consider when we examine a steam system.
Q: Why does Enercon collect so much data before the sizing of an Enercon Venturi Unit?
A: To properly size any condensate removal technology, whether it be venturi technology or a traditional mechanical steam trap, it is necessary to have a complete understanding of not only the condensate loads but also any secondary and tertiary related factors at each point a unit is installed in the system. These secondary and tertiary factors include considerations such as the exact operation a unit is performing; understanding the equipment associated with any operation; where in the system is the unit’s location; is the condensate being returned; if returned then the pressure, lift, distance and to what is that return; what effect does factors such as an indoor system versus outdoor system, humidity, temperature, etc. have on the system; is the piping design of the system proper; etc.
It is only in understanding these and other factors can a venturi, and a mechanical trap for that matter, be properly sized to maximize the efficiency of complete condensate removal while minimizing associated energy loss.
Q: How is the Enercon Venturi Unit more efficient, more economical, and permanent in comparison to existing conventional mechanical steam traps?
A: According to the North Carolina Dept. of Commerce’s Profiting From Energy Conservation “The prime function of a steam trap is to remove condensate from the steam system at the same rate as it is being produced.” This means then that no mechanical steam trap can accomplish its reason for being, only the venturi type can.
Condensate in a steam system reduces heat transfer, increases equipment damage, and causes erosion, corrosion and water hammer in the piping system. It is critical to purge condensate completely, quickly, and efficiently.
Every condensate removal device, be it an Enercon Venturi Unit or a mechanical trap, has an orifice. Whereas the Enercon Venturi Unit releases condensate through a single, fixed part utilizing continuous flow technology; a mechanical trap operates on a batch system – they open when filled with condensate and close when the level of condensate drops.
A properly sized Enercon Venturi Unit operates continuously in the lower end of a Steam Loss to % Condensate Capacity chart while a mechanical trap (whether it’s open/shut mechanism is activated by internal floats, buckets, bimetals, bellows or discs) ramps up into the upper ranges every time it opens. Therefore, in normal operating steam processes, a properly sized Enercon Venturi Unit on day one of installation is up to 3% – 4% more efficient than a perfectly operating, brand new mechanical trap. Multiple clients have proven this in both laboratory setting tests and field tests. These tests have been performed under both general field operational comparisons and more defined Six Sigma parameters. In every test in which Enercon has been allowed to properly size the venturi, Enercon’s Venturi Unit has measured superior in performance.
This superior performance only increases as the mechanical trap begins to wear out. On 24-hour-a-day applications, mechanical traps cycle several times a minute resulting in several million cycles a year, resulting in, at best wear and leakage at worst, complete breakdown. This is why lower quality mechanical traps can experience complete failure in six months or less. Even for the best quality mechanical traps, which can last 3 – 5 years before total failure, the wear and tear from the repeating purge cycle results in performance degradation long before total failure. Due to this degradation, it is not unusual for the entire mechanical trap population of a plant to be operating at 15% to 30% below its maximum, as installed, efficiency. On the other hand, since the Enercon Venturi Unit operating with no moving parts, does not experience this life cycle and the performance characteristics experienced in year twenty will be exactly the same as that experienced on day one.
Q: Why is the Enercon Venturi Unit superior to existing mechanical trap technology in handling varying loads?
A: A more detailed discussion on this topic can be found in the Enercon Venturi Unit Technology Section.
The Enercon Venturi Unit is sized to remove 100% of the maximum condensate load produced at the heat transfer point at a specific location in the system. With the Enercon Venturi Unit, steam traveling at the speed of sound continuously forces the much slower, denser condensate through a precisely sized opening. This denser condensate, occupying the venturi, blocks live steam from escaping. At 100% capacity, it is easy to understand there is no space for the steam to pass through while allowing the condensate to continuously be removed as it is being produced. But varying, not constant, loads are the norm. The question is how well does the Enercon Venturi Unit handle this varying capacity – does it lose unacceptable amounts of steam when condensate occupancy is less than 100%? Actually, the opposite is true. An Enercon Venturi Unit handles varying loads more efficiently than mechanical steam traps within their operating range. First, since the Enercon Venturi Unit is continually removing condensate from a system, the size of the venturi is 3 to 4 times smaller than a correspondingly sized mechanical steam trap since, by design, there is no condensate flow from it for about 2/3 of its typical operating cycle.
Secondly, a continual flow technology is subject to the dynamics of two-phase flow physics. When the load drops below 100% capacity, the physics of two-phase flow, along with the magnification effect the venturi design, causes a violent turbulent mixture of steam and condensate. This turbulence causes the condensate to still function as a successful barrier to steam losses. The accompanying graph plots such an event on an unregulated load (unregulated meaning the same amount of steam flows through the heat transfer device regardless of the BTU’s required during the process). With regulation the simultaneous changes occurring in steam flow amounts and pressure allows our unit to handle a far greater range of operation.
A modulating or solenoid control valve eliminates any issue of an Enercon Venturi Unit’s application in a varying pressure environment. Hampton Affiliates, a leading lumber company which converted multiple mills to the Enercon Venturi Unit system stated: “Our operations are all zone control, so we have a constant variable load situation. (Enercon) traps perform with excellence in this type of environment.” (Timber Processing magazine July/Aug. 2004)
Q: What are the anticipated financial and performance results in a complete facility conversion from mechanical traps to Enercon Venturi Units? What are the results?
Historically, when action is taken implementing Enercon’s technical evaluation with the installation Venturi Units, our customers typically report the following:
- Increased Facility and Equipment Operational Efficiency;
- Improved Product Quality;
- Reduced Energy Costs of 10%-35%+;
- Reduced Carbon Footprint on a same scale
- Reduced Water Demand and Chemicals
- Virtual Elimination of Steam Trap Maintenance and Failed Steam Trap Related Equipment Repair Expenses;
- Reduce Condensate Related Equipment Damage;
- Solutions to some Steam Related Problems such as Low and Inconsistent Temperatures, Trap-Related Pressure Drops, High Back Pressure and Water Hammer;
- Improved Facility and Environment Safety
The result is that most customers experience project paybacks less than 12 months with some extreme cases experiencing payback less than 3 months. And these savings are repeated annually as the Enercon Venturi Units are a permanent solution with minimal, if any, maintenance.
Q: What are the results of conversion to the Enercon Venturi Unit when a company believes it has a first rate steam trap maintenance program?
A: TO ACHIEVE LESS THAN A 5% TRAP FAILURE RATE, The Department of Energy (Energy Tips – 6-99) states that a facility needs to perform weekly inspections of its systems 150 psig and above, monthly inspections of its systems in the 35 psig to 150 psig range and annually inspect its systems below 35 psig.
Almost every production and maintenance person will tell you that this level of testing is unrealistic as is the immediate replacement of every trap as it reaches a certain level of degradation/failure. Plants do not have maintenance budgets that allow for such. Just the weekly testing of a 500 unit facility would require two, or more full time persons. Then add to that the personnel necessary to change faulty units as they are found along with the cost of replacement traps, fabrication, sectional shut down, and installation and you can see that such recommendations are just not practical. Steam traps are typically viewed as a low priority item and are changed on an ‘as needed’ basis.
As a result, The Alliance to Save Energy claims its studies show that on average 15% to 20% of steam traps in a facility will be inoperative – completely failed either open or closed. An English study claimed that 36% of the traps it examined were not functioning properly.
ENERCON UNITS ARE PERMANENT – To this day, Enercon has never had an Enercon Venturi Unit returned for non-performance or wear. Plants that converted to Units as long as 25+ years ago report that the units are still performing exactly as they did upon installation even when the plant has performed zero maintenance on the units. Plants in which Enercon performed system reviews 13+ years after installation of Enercon Venturi Units and implementation of technical suggestions showed zero wire draw on every inspected/measured unit, performance measurements exactly as on day one of installation on every tested unit, and exact pressure along the entire length of the operating system as designed for.
Even in systems experiencing severe chemical and corrosion problems, these issues have been typically resolved with a blowdown program of the Y strainer each Enercon Venturi Unit includes.
Q: In what type of applications do the Enercon Venturi Units efficiently operate?
A: Enercon Venturi Units are operating efficiently on tracing lines, unit heaters, humidifiers, drip legs, steam headers, submerged coils, heat exchangers, jacketed coils and other applications. Enercon Venturi Units are being used in facilities ranging from small, simple, low pressure systems to huge, complex, multi pressure, multi- process systems. Existing clients encompass almost every industry and application – petrochemical, lumber, plating, chemical, pulp & paper, packaging, pharmaceutical, food & beverage, hospitals, large buildings, airports, universities, dairy industries, power generation, etc. from small individual plants to multi operational, multi facilities of Fortune 500 companies.
On completely converted plants, Enercon technology has been responsible for and supplied units to have replaced, on average, 99% of the existing conventional traps. It is company policy not to ship an Enercon Venturi Unit if it cannot perform the task intended or if there is not an economic benefit for its purchase. In the rare instances where Enercon technology is not appropriate, we will present the correct alternative and whether cost justified.
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