steam & condensate systems: effectively manage the · pdf filesteam & condensate...

Steam & Condensate Systems:Effectively Manage the Steam and Condensate Energy Resource to Improve Energy Efficiency,

Increase Profitability, and Maximize Productivity

Author: Mike SeagleLast Revision Date: March 2014

Version: 3.0

WhitePaper

Table of Contents1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32. Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 A. Plant Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43. Typical Plant Challenge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 A. Key Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .74. Effective System Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 A. STEP I Actions – MANAGING THE STEAM TRAP POPULATION . . . . . . . . . . . . . . . . . . . . 8 B. STEP II Actions – IMPROVE STEAM USING EQUIPMENT . . . . . . . . . . . . . . . . . . . . . . . . . 8 C. STEP III Actions – ENTIRE STEAM SYSTEM BALANCE . . . . . . . . . . . . . . . . . . . . . . . . . . .95. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .96. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Table of Figures

FIGURE 1 – Steam is used for a wide variety of applications such as heating and driving force for mechanical power in refineries and petrochemical plants.

FIGURE 2 – For efficient operation, condensate must continuously be drained from the steam space to ensure dry saturated steam for maximum heat transfer capability. Armstrong steam traps provide protection and extend the overall life of the steam system by effectively draining condensate and eliminating air and incondensable gasses.

FIGURE 3 – Armstrong combines its Trap Valve Stations (TVS) with manifolds in a package called the Condensate Collection Assembly (CCA). This prepackaged assembly offers many great benefits—cost savings in assembly, design flexibility and reduced purchasing and design time. The CCA with TVS 4000 Series and the Inverted Bucket Traps is guaranteed for three years.

FIGURE 4 – Energy Engineers and Unit Operators want to maintain efficient performing systems and reduce energy and maintenance costs associated with steam systems.

STEAM AND CONDENSATE SYSTEMS: EFFECTIVELY MANAGE THE STEAM AND CONDENSATE ENERGY RESOURCE TO IMPROVE ENERGY EFFICIENCY, INCREASE PROFITABILITY, AND MAXIMIZE PRODUCTIVITY

Introduction

Nearly 49% of all fuel burned by U.S. manufacturers is used to raise steam2. Steam has been a primary mode of transferring energy since before the Industrial Revolution. Steam is used to heat raw materials and treats semi-finished products. It is also a power source for equipment, facility heating, and electricity generation. Refineries, petrochemical plants, power plants, pulp and paper mills, municipal facilities, food and pharmaceutical companies use condensate drainage equipment to ensure water does not collect in their steam lines and process equipment, which will degrade the overall system. Steam traps and condensate pumps are used to ensure condensate is properly drained from steam tracing and distribution lines. Plants depend on their critical process applications such as tanks, evaporators, heat exchangers, re-boilers, turbines, etc. for production.

FIGURE 1 – Steam is used for a wide variety of applications such as heating and driving force for mechanical power in refineries and petrochemical plants.

Maintaining an efficient steam system represents a significant opportunity for savings in most plants. By optimizing the steam and condensate system, most sites can realize substantial energy savings with improvements upwards of 30%+ steam savings achievable at some sites. Steam accounts for over $2.6 billion per year of purchased energy for manufacturing sites in the US as of 20063. With continued governmental mandates and increasing fines, manufacturing sites will be forced to reduce their carbon footprint to meet regulations set by the U.S. Environmental Protection Agency (EPA).

Lack of detailed and educational information often prevents significant improvements from being realized in the productivity, efficiency, reliability, and safety of steam systems. Process engineers and maintenance personnel are constantly facing challenges with the equipment they must keep operating effectively to ensure profit margins and reduce downtime. There are many options and parameters that must be evaluated when choosing the proper condensate drainage device for a given application for plant personnel. Additionally, very little information is available for selecting/sizing the proper choice.


Background

Steam, which is formed when water vaporizes into a gas, has been used since before the Industrial Revolution for transferring energy. This vaporization process can only occur when the water molecules are given enough energy to change phases from liquid to vapor form. The amount of energy required to cause this phase change is called “latent heat”.

Most manufacturing equipment and steam systems are designed to utilize the latent heat given up by steam as it condenses. To ensure efficient operation, the steam space must be completely and continuously drained of condensate, dirt, debris, scale, air, and incondensable gasses so the entire heat transfer surface is exposed to steam. Removing condensate from steam lines by manually opening valves is not only an extremely inefficient and labor intensive task, but it also results in excessive waste in leaking and costly steam. Steam traps are used to ensure automatic drainage of condensate from steam system and will also vent air and incondensable gasses from the distribution line or steam using equipment without losing live useful steam.

FIGURE 2 – For efficient operation, condensate must continuously be drained from the steam space to ensure dry saturated steam for maximum heat transfer capability. Armstrong steam traps provide protection and extend the overall life of the steam system by effectively draining condensate and eliminating air and incondensable gasses.

An effective steam trap improves the efficiency of a steam system in the following ways:• Vents air and incondensable gasses particularly during start-up to prevent insulating barriers

which reduces effective heat transfer• Removes condensate at or near saturated steam temperature to ensure dry saturated steam for

heat transfer• Condensate near saturated steam temperature is available for recycle which reduces energy

costs, make up water, and chemical costs

Plant Applications:

There are three basic categories for steam trap applications:1. Distribution Line(s) Drip Pockets2. Tracing and Jacketed Piping3. Process Heating



The most common requirements for steam traps in most plants include the areas of• Heating/ Sterilization• Motive• Atomization• Propulsion/Drive• Humidification• Moisturization• Cleaning

An average size oil refinery will have around 5000+ steam traps installed in various areas of the plant with larger refineries with steam trap populations of up to 20,000 traps. A large majority of these steam traps are used for distribution and tracing while others are used for process operations and power generation.

Figure 3 – Condensate Collection Assemblies (CCA) Armstrong combines its Trap Valve Stations (TVS) with manifolds in a package called the Condensate Collection Assembly (CCA). This prepackaged assembly offers many great benefits—cost savings in assembly, design flexibility and reduced purchasing and design time. The CCA with TVS 4000 Series and the Inverted Bucket Traps is guaranteed for three years.

Typical Plant Challenges

High system operating and maintenance costs continue to be challenges that managers face at process plants and industrial sites which impact their economic performance, safety, and regulatory compliance. Steam systems present an area of opportunity to reduce energy costs due to frequent steam trap failures and damaged steam equipment.


Intensive steam users, such as petrochemical plants and refineries, must continue to improve their ratio of product output per unit of steam they consume. This is a governmental and industrial standard that involves reducing their Energy Intensity Index (EII) value and achieving greater efficiency in operations.

Blocked condensate drainage locations, blowing or leaking steam, flooded heat exchangers, damaged turbines, water hammer, and poor heat transfer capabilities are some examples of problems and safety concerns that plants face with regards to steam traps and effective condensate drainage. Steam that passes to the atmosphere without condensing in the system is a waste of money. When condensate is not returned to the boiler it results in energy losses, plus an increase in feed water and chemical treatment. Additionally, condensate trapped in the steam system can cause the greatest concern and adverse effects with the potential for ineffective heat transfer, flooding, fouling, water hammer, corrosion, and erosion of the steam system. Water hammer can lead to the most damaging of these potential effects and is a major safety hazard that can be fatal. When water hammer occurs, a sudden hydraulic impact can occur which can severely damage distribution lines, valves, unions, gaskets, and equipment.

Other areas where we work with engineering managers are:• Frustration and challenges of unscheduled expenditures due to:

o Flooded heat exchangerso Damaged Turbines from wet steam & condensate slugso Damaged Flare Tips or Flare outso Flooded/Fouling/Bypassing Reboilerso Steam Trap Failure Rate Maintenanceo Tank Coils ineffective heatingo Sulfur Pits and Jacketed Piping flooding

• Continuing ineffective operation practices and wasting money on:o Inefficient steam trapping practices, selection, and sizingo Slow roll/hot standby of turbineso Steam leaking from open bypass/blow down/bleed valves used to “protect the

system”• Concerns over lost production due to:

o Turbine tripso Product lines freezing, especially due to steam tracing failureso Reboiler failures

• Difficulties with process problems:o Production bottleneckso Low cut pointso Degrading vacuum levels

• Issues dealing with safety & environmental pollution:o Steam & condensate system water hammero Burn hazards from leaking steam and hot condensateo Flare outs (ignition issues)


o Downtime due to equipment failureso Hot condensate discharge to sewer (discharge temperature & chemical treatment)o Wasteful CO2 emissions from generating vent or lost steam

• Lack of adequate steam system specialist knowledge to understand and address problems

• Limited resources to make system improvements when priority is to run plant operations or in other areas

• Challenges to achieve goals and implement best practices, and maintain those programs• Trouble with understanding and optimizing energy usage for the entire plant• Difficulty justifying and accurately predicting the true savings of making improvements

FIGURE 4 – Energy Engineers and Unit Operators want to maintain efficient performing systems and reduce energy and maintenance costs associated with steam systems.

Key Objectives:

Plant Managers’ key objectives for maintaining a safe and efficient steam system include:1) Managing the steam trap population to lower overall system costs2) Creating best practices for sizing and selection of steam traps to minimize life cycle

costs (i.e. identifying applications where specific requirements are needed such as copper tracing blockage issues, superheat, low temperature tracing, etc.)

3) Optimizing steam using equipment and applications for maximized productivity (i.e. identifying high ROI opportunities and developing implementation solution plans for applications such as reboilers, turbines, flares, vacuum systems, etc.).

Sizing and selecting the proper condensate drainage device for a given location depends on a number of different parameters including condensate load, back pressure, air and incondensable gas content, inlet pressure, modulating versus non-modulating conditions, etc. For typical distribution drip service steam traps the condensate load requirements are relatively small during normal operation and the operating time is continuous, as well as they are usually located outdoors. Thus to optimize efficiency, the steam traps installed on these installations must maintain high efficiency while giving reliable and long term operation. If the wrong steam trap is installed in a given application, the results can be disastrous. Upmost attention must be given in developing a plant wide standard for installing, selecting, and sizing the appropriate steam trap for the given application.


Effective System Management

A Three-Step Best Practices Approach can help address all the above concerns.• Step I helps reduce total system costs through effective management of the steam trap

population.• Step II assists with improving steam using equipment.• Step III supports optimization of a plant’s entire steam balance.

STEP I Actions – MANAGING THE STEAM TRAP POPULATION

1. Site has approximately number traps. Site has not had a comprehensive steam trap survey in an unknown number of years. Individual unit testing has been conducted on an as needed basis or to address troubleshooting with the steam system.

a. Site should standardize on annual steam trap surveys and allow budget for maintenance response to minimize failure rate of steam traps.

b. Steam trap survey to be scheduled.c. Maintenance or Operator support and involvement is encouraged during our

surveys to assist our technicians and increase awareness for site personnel.d. A key site contact is requested to help facilitate the survey crew, if available.

2. Implement a trap management software program, such as SteamStar®, to assist with steam trap survey and maintenance schedules and reporting. SteamStar® can provide the following features and benefits:

a. Quantity of traps by application b. Location of equipment c. One database of information where: - Information is constantly updated to provide the most up to date data for all

personnel - Annual surveys are archived for future retrieval and reference d. Ability to generate reports: - Steam and monetary loss - Defective trap report - Executive summary - Trap evaluation by applicatione. Data helps justify ROI decision making

3. Develop STORE or SAP numbers for steam traps and keep inventory for maintenance activities - STORE or SAP’s can be incorporated into the Site Standard document to further help customize the documents for your site and further help standardize on how the site manages the steam system.

4. Training for Maintenance and Operators5. Maintenance Response from survey using information and tools provided to repair/

replace steam traps and applicable piping to reduce failure rate and increase system efficiency.

6. Follow up annual or bi-annual steam trap surveys to manage steam trap population and reduce failure rate. Target Failure Rate should be in the single digits.


7. With real time steam trap monitoring, you will recognize the benefits of monitoring your trap population 24/7/365 for critical and non-critical applications. Steam trap monitoring combined with a steam trap management software provides immediate notification of failed transmitters and their accurate location for fast resource deployment to minimize interruption of steam system operation and wasted energy.

STEP II Actions – IMPROVE STEAM USING EQUIPMENT

There are significant savings associated with process type equipment. A Process Heater/Reboiler or Turbine study usually offers the greatest potential return on investment in my experience. For steam using equipment that struggle with increased maintenance costs, unexpected downtime, equipment damage, process problems, condensate bypass, and other issues there are often opportunities for immediate improvements with proper condensate removal. A detailed evaluation and history report needs to be evaluated and outlined by a properly trained steam system expert to thoroughly understand the application and how best to optimize the system. Data collection of all process parameters, historic trending data, heat exchanger data sheets, physical inspection of application are all needed to properly diagnose the system and provide best practice approach for improvement recommendations. Savings and improvements associated with process steam using equipment can far outweigh savings associated with Step I activities in some cases since increasing productivity and debottlenecking operations can be exponentially greater than repairing steam leaks. This is not to say that Step I should be avoided as it is an instrumental step to optimize the steam system.

A Compressed Air System study would also be a recommendation as these areas often times offer significant room for improvements.

STEP III Actions – ENTIRE STEAM SYSTEM BALANCE

Studies include a site-wide steam system balance with a dynamic system balance to ensure that recommendations will realize the opportunities stated. Reviewing the steam system balance may open up multiple energy-saving opportunities. Petroleum refineries utilize steam at several pressure levels ranging between high and low. To reduce these energy losses, pay close attention to the number of operating steam turbines that lead to LP steam venting, and continuous use of pressure-reducing valves to obtain LP steam from high-pressure headers. Process engineers should give priority to optimizing the steam balance to minimize both situations.

Petroleum refineries offer endless opportunities for energy cost reduction.


Conclusion

A comprehensive understanding of steam systems and steam trap technology, as well as an awareness of the importance of an effective steam trap management program is essential to reduce energy costs and maintain an efficient steam system. Armstrong specializes in steam systems of all types in all different manufacturing industries such as refining, petrochemical, oil and gas, power generation, pulp and paper, food processing, pharmaceutical, educational, municipalities, etc.

Armstrong and their representatives offer the products and services to assist any steam using sites to realize increased energy efficiency, extended reliability, and maximized productivity. For more information on how Armstrong and representative affiliates can help optimize your site, please visit www.armstronginternational.com. To locate and contact your local Armstrong sales representative or an Armstrong solutions specialists, please visit www.armstronginternational.com.

Armstrong InternationalNorth America • Latin America • India • Europe / Middle East / Africa • China • Pacific Rimarmstronginternational.com

White Paper 1504-APrinted in U.S.A. - 3/14

© 2014 Armstrong International, Inc.


References

1. Steam Distribution & Utilisation – Bureau of Energy Efficiency, UK http://www.scribd.com/doc/100796783/2-3-Steam-Distribution-Utilisation

2. US Department of Energy – http://www1.eere.energy.gov/manufacturing/tech_deployment/steam.html

3. US Department of Energy Purchased Electricity, Natural Gas, Steam by type of Supplier, Mfg., Industry, & Region –

http://www.eia.gov/emeu/mecs/mecs2006/2006tables.html

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