HOW TO AVOID DANGER, DAMAGE, AND DOLLARS LOST IN STEAM SYSTEMS. JAMES R. RISKO President TLV CORPORATION Charlotte, NC

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1 HOW TO AVOID DANGER, DAMAGE, AND DOLLARS LOST IN STEAM SYSTEMS JAMES R. RISKO President TLV CORPORATION Charlotte, NC ABSTRACT No one wants to experience Danger, Damage or Dollars lost in a steam system, but common site management practice often overlooks a critical component necessary for successful system performance; maintaining the steam trap population to original design specifications. Some users may define necessary steam trap management as just a focus on the identification and repair of leaking traps according to a fixed budget. However, this type approach does not match the criticality of proper drainage of a steam system to a plant s successful operation. Correspondingly, the priority and implementation of corrective maintenance response to failures may be reduced to a reactive status, subordinate to other site maintenance needs. In such programs, the site may experience significant - but avoidable safety, reliability, production, and energy issues. A different priority and management method a paradigm shift-to analyze and improve the relative health of a steam system is needed. This method focuses on steam trap population condition threshold values to obtain an optimized steam system that provides best quality heat safely and reliably. Such a paradigm recommendation has been presented previously (1), and this paper provides supplemental analyses to justify the continuous time and monetary investment required. CURRENT STRATEGY AND STRUCTURE Your Steam System There is only one efficient manner to convey mass amounts of thermal energy efficiently to a process application, through a high performance steam system. A site would not willingly accept low quality feedstock as a critical component of production, so why accept poor quality thermal energy? When properly designed, steam systems should be relatively easy to understand the crucial elements necessary to sustain target production rates. Your steam system is an important asset (FIGURE 1) that provides production heat, but commonly sites unknowingly reduce its value by losing sight of the importance to drain condensate from the system-and this can have disastrous effects (4). Basically, there are two important characteristics to consider for a high quality steam system; the supply of dry steam for turbine, atomizing, flaring, and soot blowing applications; and the rapid drainage of process heat exchange equipment to optimize each process application for production quality, quantity, and reduced fouling / maintenance issues (8, 9, 11). (FIGURE 2) When steam quality is reduced, typically because the boilers are either pushed to supply steam in in greater quantity than their rated capacity (sometimes to overcome steam leaks) - or due to condensate that has not been effectively removed; then the condensate that remains causes multiple problems. Typical examples include water hammer from pooled condensate that is propelled downstream by high velocity steam, or stratified/fouled/corroded heat exchange equipment that experiences stall conditions. (FIGURE 3) When the painful events happen to sites with non-optimized steam systems, employees may come to expect the amount of incidents as normal, a sort of necessary burden that befalls all steam systems. In addition to the above examples, it is common for plants to suffer critical compressor or flare issues, or even shutdowns all caused by condensate that was not removed effectively. (2, 4). (FIGURE 4) An existing dilemma is that the correlation of such a low cost item, a failed steam trap retaining condensate, to being the cause of a major system failure or plant shutdown is not often made. Steam traps are sometimes considered as commodity rather than specialty items, and therefore thought as having little impact on total plant reliability. It follows that it is not often considered that having a steam trap that no longer discharges condensate (Discharge Failure) can be similar to the effect putting a rag into the exhaust of an expensive sports car. The equipment may be worth $ millions, but without proper and immediate discharge of spent fluids, it operates poorly and may be damaged. The metrics that justify managing a trap population may be wrongly based on recovering steam loss. Survey database studies reveal that steam trap populations may have 18% of traps failed in a leaking mode, while only 13% are failed blocked. (FIGURE 4)

2 It becomes such a simple economic analysis to determine the return on investment for fixing leaking steam traps that this practice becomes the priority. However, the analysis to correlate COLD Failures from blocked traps requires historical data of prior incidents and the loss values associated with the events. Unless there is a proactive program to track those losses caused by traps that were blocked, valved-out, or removed; then the causal relationship of blocked traps to system damage goes either unnoticed or difficult to valuate. Since the valuation is difficult, or unknown due to personnel switching positions, the short-term gain of replacing HOT Failures (leaking steam traps) is incorrectly given priority. However, to avoid danger, damage, and dollars lost it is best to fix COLD Failures first (1, 4,). The question of, Why should the repair of nondischarging traps be given the highest priority?, is easily understood by considering the dynamics causing water hammer in systems that can destroy piping particularly at risers and expansion joints. High velocity steam propels pooled condensate, particularly dangerous when the piping s crosssectional area is completely flooded. The results can be disastrous. (FIGURE 5) Just as an example of the power and danger, in one recent instance a petrochemical site experienced their 24 steam main being moved a distance of about 5 for a 400 long section due to water hammer. The support girders were twisted and the piping was bent - it was just short of a miracle that the line did not completely collapse. When the drain taps were opened, water spewed from the drain for hours. If the power of rapidly propelled condensate can move this mass, imagine the effect on turbine blades, vacuum jets, flare tips, flange gaskets, or steam nozzles. To prevent these dangerous safety and reliability events, it is critical to have sufficient drainage from the system using adequate CDL (Condensate Discharge Location) drainage points as shown. (FIGURE 6) STRATEGIES SHOULD CHANGE? What Happens After A Survey A typical state of a trap population may reflect over 50% of traps failed if the site has not proactively surveyed and replaced traps on a high priority basis for the preceding 3-4 years. A worsening effect is that databases commonly show In-Service traps to number substantially less than the plant s original Design traps total. (GRAPH 1) As trap populations deteriorate so does the piping system; and subsequently destructive incidents occur. Once a painful event happens, it is common that focus switches back to the steam trap population and a new survey is contracted to learn the current health of the system. So, it becomes a regular expectation that when a site renews their focus on steam traps after years of reactivity; that there will be a substantial number of the traps failed-and a heavy burden to repair those traps. The maintenance, personnel, and economic burdens on those sites become almost unmanageable. Consider a site with 4,000 steam trap failures. In order to bring the site back to 10,000 traps In- Service, it is necessary to replace 333 traps per month. This means 3-4 full-time maintenance teams. How many sites have that much of a labor resource readily available? (GRAPH 2) Site management realizes that in order to reach the target of 10,000 In-Service traps, the existing failures all have to be repaired. This process is referred to as Zero Reset Maintenance (ZRM ) (GRAPH 3) However, the reality of site events is that even if 3-4 response teams were assigned to accomplish ZRM, throughout the year they commonly are pulled off steam trap replacement work (considered not a high enough priority?) and reassigned to other repair responsibilities. With lessened effort to fix failures, the state at the end of the year may show that there were only 2,004 traps replaced, with 1,996 traps remaining to be repaired. (GRAPH 4) It can be a bit embarrassing, having only completed ~50% of the maintenance work over the 12-month period. This can motivate one of the more risky actions to reduce the remaining workload by simply removing additional traps from service. Whether from lesser experience or because no critical damage occurred when some traps were out of service some sites justify to remove traps from service without a proper design analysis to support the MOC s required. The thought process might simply be, We haven t experienced and issues so those traps aren t needed! Such action is a high concern decision to overrule the original design of a Professional Engineering firm and redesign the steam system drainage on limited system design analysis. What often is not considered is that between the date of deciding to remove additional traps from service and the next time period when traps will be surveyed with failures replaced there could be

3 additional 1,000 or 2,000 new failures. The general deterioration of a plant s steam system under such a scenario caused the Good steam traps to fall under critical threshold values for safe and reliable operation and the total In-Service traps also is reduced, leaving even a smaller pool of CDL for the future. (GRAPH 5) The trend of the Good traps state is moving in the wrong direction in Graph 5 and can never be trusted to provide safe or reliable operation in a plant. Eventually, critical thresholds of Caution, Warning, and Danger are crossed as the plant becomes less and less sustainable and safe. Unless there is a fixed minimum threshold of Good traps that must be maintained, the deterioration of the plant becomes hidden not to be exposed until a painful event of Danger, Damage, or Dollars lost is realized. A sustainable steam trap population management program needs to be implemented and maintained year to year to keep annual failures at a manageable level (5). This is part of the 4 Pillars of Industrial Energy Efficiency (3) needed for sustaining a high performance steam system. If a site wants to mitigate risk from problems caused by retained condensate, it should follow the structure shown that requires ZRM each year. This is a proven method to help maintain effective drainage of the system for optimal performance and reliability. (GRAPH 6) EVENTS AND ECONOMICS Maintenance Budgets Are Fixed And May Be Insufficient for ZRM A fixed maintenance budget is the enemy of protecting the system and related equipment. Priority should be established at all cost to make certain a steam system is adequately drained of condensate before it can cause damage or waste high value energy CONCLUSIONS Obtaining the necessary budget to maintain a ZRM strategy (optimizes Good trap total) requires the support of site management. It is hoped that the information herein may help validate a request for funds as needed to obtain a high performance steam system that optimizes safety and production. RELATED TOPICS & LITERATURE CITED 1. Risko, James R., Why Bad Things Happen to Good Steam Equipment, Chemical Engineering, New York, NY, pp , (March 2015) Risko, J. R., Use Available Data to Lower System Cost, Presented at the Industrial Energy Technology Conference, New Orleans, LA, (May 18, Session 7, 2011) Rossiter, Alan P., The Four Pillars of Industrial Energy Efficiency, Chem. Eng. Progress, pp (May 2015). 4. Risko, J. R., Beware of the Dangers of Cold Traps, Chem. Eng. Progress, pp (Feb 2013) Walter, J. P., Implement a Sustainable Steam- Trap Management Program, Chem. Eng. Progress, pp (Jan 2014) Russell, Christopher, Outsourcing Energy Performance: It s Potential for Industrial Energy Efficiency Programs, American Council for an Energy-Efficient Economy, Report IE1402, (March 18, 2014) 7. Risko, James R., Understanding Steam Traps, Chemical Engineering Progress, New York, NY, (February, pp ) 8. What Causes Stall to Occur, TLV Co., Ltd., Kakogawa, Japan Risko, James R., Handle Steam More Intelligently, Chemical Engineering, New York, NY, November, pp Steam Trap Losses What It Costs You, TLV Co., Ltd., Kakogawa, Japan Risko, James R., Steam Heat Exchangers Are Underworked And Over-surfaced,

4 Chemical Engineering, New York, NY, November, pp Risko, James R., Effective Drainage of Condensing Equipment, Fluid Controls Institute, Technical Sheet #ST106, Cleveland, OH, February. ffectivedraincondensingequip.pdf 13. Risko, James R., Steam Traps Operating Principles and Types, Fluid Controls Institute, Technical Sheet #ST107, Cleveland, OH, April. 7OperatingPrinciplesandTypes.pdf 14. Steam Trap Management System, TLV Co., Ltd., Kakogawa, Japan Risko, James R., Ask the Experts Optimize the Entire Steam System, Chemical Engineering Progress, New York, NY, February, p What is Water Hammer, TLV Co., Ltd., Kakogawa, Japan.

5 ESL-IE Optimize Steam OptimizeFigure Steam1Systems Systems Figure 2 Turbine Heat Exchanger Supply Dry Steam Drain Condensate Fast 1

6 Figure 3 Dangerous Events Reduced Productivity From HPAC (Heating/Piping/AirConditioning) Water hammer can cause serious injury or damage Shutdowns Uneven heating Poor quality Corrosion Table 1 Failure(Event( Failure(Event(Loss( Historical(Value(!!! Flare(Issues( Analyzer(Failure(Plant(Shutdown( Main(Compressor(Failure( $750,000(9($1.7(Mil(( $1(Mil( $3.6(9($20(Mil( ( (( 2

7 Figure 4 Steam Trap FAILURES 13% COLD COLD Failure 18% HOT HOT Failure NO Drainage COSTLY Drainage Fix Cold Failures 1 st! Figure 5 Condensate Slugs Cause Water Hammer! High Velocity Steam 3

8 1 st Figure Priority 6 1 st Priority 1 st Priority - REMOVE CONDENSATE! Current State of a Trap Population Graph 1 - Current State of a Trap Population Original Traps In-Service Why This Gap? GOOD 8 4

9 Graph 2 - Failures to Repair 9 Graph 3 - Zero Reset Strategy 10 5

10 Graph 4 - Reality 11 Graph 5 - Wrong Direction 12 6

11 Graph 6 - Avoid Danger, Damage, & Dollars Lost 13 7