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Making Sure Steam Piping Is Safe

Pharmaceutical Processing

<<This document seeks to provide methods for screening high pressure (below 300 psig) piping systems, that may normally be encountered in industrial steam plants, to identify safety issues related to the design and/or installation of pipe, valves, flanges, and components used in these systems. The following is not an all inclusive guide to safe practices, but instead attempts to give some insight for understanding and conducting a simple screening of a steam piping system. This review of what is installed is important for every steam plant operator to help make sure that an unexpected accident is not waiting the next time someone opens a valve or puts a steam line into service.>>

Lack of Steam Trap Knowledge Is the Weakest Link

PM Engineer

<<The weakest link when it comes to steam systems may not be an individual component, but a fundamental lack of knowledge. For example, a steam trap, when properly installed, may be the most beneficial but least understood piece of equipment in the system. However, the lack of knowledge about steam traps and how they function can result in excessive energy loss, compounded environmental costs, productivity problems, and yes, safety concerns for personnel and property.>>

Steam Trap Performance Assessment

U.S. Department of Energy

<<Various types of performance assessment equipment can be used as part of a proactive steam trap maintenance program to significantly reduce energy losses in steam distribution systems. Approximately 20% of the steam leaving a central boiler plant is lost via leaking traps in typical space heating systems without proactive maintenance programs. Relatively simple equipment and programs can easily cut losses in half. Intermediate equipment and programs can cut losses in half again. The best equipment and programs can reduce losses to less than 1%.>>

Steam Digest Volume IV

U.S. Department of Energy

<<BestPractices, under the U.S. Department of Energy's Industrial Technologies Program (ITP), helps U.S. manufacturers maintain global competitiveness through strategic energy management, including the use of energy-efficient technologies.>>

Steam Utilization [PDF]

Spirax Sarco

<<Like many other substances, water can exist in the form of either a solid, liquid, or gas. We will focus largely on liquid and gas phases and the changes that occur during the transition between these two phases. Steam is the vaporized state of water which contains heat energy intended for transfer into a variety of processes from air heating to vaporizing liquids in the refining process.>>

Steam Hook-Ups [PDF]

Spirax Sarco

<<Selection of the most appropriate type and size of control valves, steam traps and other fluid control valves, steam traps and other fluid control equipment, and installation in a hook up enabling these components of a system to operate in an optimal manner, all bear directly on the efficiency and economy obtainable in any plant or system.>>

User's View of Steam Traps

Plant Engineering Magazine

<<The main purpose of a steam trap is to discharge condensate without releasing steam. There are four main types of steam traps that accomplish this in different ways. Since the energy wasted by a trap is usually unseen, it is tempting to ignore maintenance. Unfortunately, neglecting faulty traps is terribly expensive. There are times when users of steam traps must help themselves. This article is written from a user's point of view.>>

Compressed Air Cleaning of Steam Piping [PDF File]

GE Power Systems

<<Cleaning of the main steam piping is required to minimize the possibility of damage to the turbine by removing weld bead deposits, pipe slag, and other foreign material which might otherwise be carried over into the turbine. Any particles that would be dislodged while operating must be dislodged during the cleaning process, and any particles that are or become loose must be removed from the system.>>

Steam Trap Sizing and Selection [PDF File]

Armstrong International

<<Condensate lying in the bottom of steam lines can be the cause of one kind of water hammer. Steam traveling at up to 100 miles per hour makes “waves” as it passes over this condensate. If enough condensate forms, high-speed steam pushes it along, creating a dangerous slug which grows larger and larger as it picks up liquid in front of it. Anything which changes the direction—pipe fittings, regulating valves, tees, elbows, blind flanges—can be destroyed. In addition to damage from this “battering ram,” high-velocity water may erode fittings by chipping away at metal surfaces.>>

Understanding Boiler Bypass Lines

Plant Engineering Magazine

REGISTRATION REQUIRED

<<Boiler manufacturers emphasize bypass lines today—and with good reason. Boilers are relatively small now. Their heat exchangers are much more efficient than are those in older boilers. And because they are smaller, modern boilers have specific flow rates and temperature needs. Consequently, many require a flow-bypass line.>>

Steam Tip Sheets

Steaming Ahead

<<One-page discussions of efficiency technologies and procedures. Most Tip Sheets show how to calculate the dollar impact of efficiency implementation. >>

An Overview of CIP Technology

Dale A. Seiberling

<<Processing and storage tanks and process piping systems comprised of pumps, interconnecting piping and valves are well understood to be CIP cleanable. The technology is equally applicable to any equipment in which solution contact can be achieved via spray or pressure recirculation and the applicable equipment may include filter housings, membrane filters, homogenizers, centrifugal machines, heat exchangers, evaporators, dryers and congealing towers, screw and belt conveyors, process ductwork, and a variety of packaging machines.>>

Heat Recovery Steam Generator (HRSG) Design

HRSGdesign.com

<<This introduction to HRSG Design is presented to provide an overview of the considerations and methods used in the thermal and mechanical design of watertube HRSG units as found in Cogeneration Plants, Combined Cycles, and the Refining & Petrochemical Industries.>>

Good Piping Practice Prevents Water Hammer in Steam Systems

ITT Industries

<<One of the most common complaints against steam heat is that a system sometimes develops a hammer-like noise commonly referred to as water hammer. It can be very annoying. However, it may indicate a condition which could produce serious consequences including damaged vents, traps, regulators and piping. There are two types of water hammer that can occur in steam systems.One type is usually caused by the accumulation of condensate (water) trapped in a portion of horizontal steam piping. The velocity of the steam flowing over the condensate causes ripples in the water. Turbulence builds up until the water forms a solid mass, or slug, filling the pipe. This slug of condensate can travel at the speed of the steam and will strike the first elbow in its path with a force comparable to a hammer blow. In fact, the force can be great enough to break the back of the elbow. Steam flowing in a system at 10,000 feet per minute is traveling more than 100 miles per hour. The slug of condensate is carried along by the steam flow.>>

The Saturated Steam Tables

Mike Rocchetti

<<This calculator is used to compute the thermodynamic properties of saturated steam. This calculator uses steam properties from the 1967 ASME Steam Tables, published by the American Society of Mechanical Engineers. This calculator allows the user to input either temperature or pressure in either metric or I-P units. The calculator then outputs the pressure or temperature, the specific volume, the enthalpy, and the entropy. The values are obtained by a linear interpolation between available data points. This calculator provides reasonable accuracy. Before I release this calculator, I must have more precise data. In the meantime, please feel free to use it, but make sure you double check your answers with another source of data - just to be safe.>>

An Introduction to Steam Boilers and Steam Raising

N.E.M Business Solutions

<<A boiler is a closed vessel in which water under pressure is transformed into steam by the application of heat. In the boiler furnace, the chemical energy in the fuel is converted into heat, and it is the function of the boiler to transfer this heat to the contained water in the most efficient manner. The boiler should also be designed to generate high quality steam for plant use. A flow diagram for a typical boiler plant is presented in Figure 12.l. A boiler must be designed to absorb the maximum amount of heat released in the process of combustion. This heat is transferred to the boiler water through radiation, conduction and convection. The relative percentage of each is dependent ulpon the type of boiler, the designed heat transfer surface and the fuels.>>

Steam Distribution

U.S. Department of Energy

<<The primary purpose of an effective steam distribution system is to link the output of the steam generation system to the steam end use equipment. The distribution system should supply high-quality steam to the end use equipment at the required rate and pressure, and with the minimum heat loss. Key components include steam distribution piping, valves, and flanges, distribution system insulation, steam traps, air vents, drip legs, and strainers.>>

Steam Specialties Calculators

Hoffman Specialty

<<Online calculators for the following: Flash Steam Loss Calculation (allows easy calculation of flash steam loss and associated energy cost, values from "Properties of Saturated Steam Tables" automatically considered – no need to look up information, allows user input of their actual cost of steam, calculates energy loss on an hourly and annual basis, allows calculation of energy savings by operating steam equipment at a lower pressure, calculates required flash tank size); Steam Pipe Sizing (allows quick sizing of steam lines, showing steam velocities and pressure drop in calculated pipe size, values from "Weight-Flow Rate" and "Velocity of Steam" charts automatically considered – no need to look up information, calculates approximate pipe size, calculates steam velocity and pressures drop per 100 feet of calculated pipe size); Sizing Condensate Return Lines (allows quick sizing of condensate return lines, values from "Weight-Flow Rate" and "Velocity of Steam" charts automatically considered – no need to look up information, calculates approximate return pipe size); Steam Loss Through Failed Trap (allows easy calculation of flash steam loss and associated energy cost through a failed steam trap, values from "Properties of Saturated Steam Tables" automatically considered – no need to look up information, calculates energy loss on an hourly basis, calculates cost of steam loss on an annual basis).>>

Making Sure the Trap Fits the Need

Armstrong International, Inc.

<<Steam traps provide the basic function of condensate removal in a steam system. However, a typical steam system can be a complex network. Matching a trap to a specific drainage application must take into account the various operating principles of steam traps as well as the specific need and conditions.>>

Steam System Troubleshooting Guide

HeatingHelp.com

<<Take the chill out of your life with HeatingHelp.com's expert solutions to all your residential and commercial heating problems>>

Steam Trap Troubles? Skip The Psychics

Mick Gerhardt

<<Give up on the psychic hotlines and don’t even consider an exorcist for solving your steam trap problems. There is a much more reliable way: Just understand how a steam trap works. That is the goal of this two-part series: to solve some of the confusion and mystery surrounding steam traps. With a little understanding of the purpose of a trap and how it works, you can eliminate much of the guesswork when deciding which type of trap to select, how to size it, and what will happen if it is not properly maintained.>>

Piping Drainage

Southern Alberta Institute of Technology

<<In the case of steam piping, it is necessary to constantly drain any condensate from the lines. If this is not done then the condensate will be carried along with the steam and may produce water hammer and possibly rupture pipes or fittings. In addition, the admission of moisture-carrying steam to turbines or engines is most undesirable. Various devices are used to remove this condensate and moisture from the lines and these are discussed in the following sections.>>

Failed Open Steam Traps Cause Waterhammer

Westinghouse Hanford Co. / DOE Hanford

<<Low pressure differential across inverted bucket steam traps or sudden or frequent drops in steam pressure can cause the traps to lose their prime and fail open. Traps should be checked regularly for proper operation. Failed traps should be repaired expeditiously. Introduction of large quantities of steam into a condensate line can result in a water hammer even if that line is vented. The location of vent lines, amount and temperature of the condensate, velocity of the steam, and condition and grade of the pipe affect the probability of occurrence and severity of water hammer. Expeditious maintenance and repair of steam system components is necessary to maintain system control and eliminate the need for compensatory measures in the system operation.>>

Ultrasonic Testing Tips for Steam Traps and Valves

Enercheck Systems, Inc.

<<STEAM LEAKS can exist anywhere in a system. Steam may be escaping through external or Internal leaks in fittings, valves or controls, from oversized steam traps, or traps that are blowing, leaking or plugged with dirt. Steam may be lost through uninsulated valves, flanges, sections of steam pipe, or through high back pressure in condensate lines caused by blowing traps. A control valve unable to close because of "wiredrawing" or undersized steam and condensate lines with no provision for utilizing flash steam could all be sources of wasted energy.>>

Boiler Water Treatment

ProChemTech International, Inc.

<<Typical boiler system problems involve corrosion of feedwater systems; scale, deposition, and corrosion in the boiler; corrosion of condensate systems; and problems due to impurities in produced steam. ProChemTech manufactures various chemical products and equipment, which when properly applied, can economically control all of these problems.>>

Direct Injection Desuperheaters (PDF Document)

Croll-Reynolds Company, Inc.

<<Steam is the most widely used heat transport fluid. Its properties are well known and its characteristics at different levels of pressure and temperature are very predictable. Steam is used for both power generation and process operations. Unfortunately these two applications have conflicting requirements; turbines require high temperature, superheated steam for optimum efficiency, process applications require lower temperatures, closer to saturation. Yet a boiler is capable of producing steam to match only one of these conditions, and the power generation aspect is the usual winner. So, if the same steam is to be used for process applications such as heating, stripping or sparging, the superheated steam needs to be reduced in temperature. Therefore, the need for a desuperheater.>>

Orifice Installation / Operating Instructions

Madden Manufacturing, Inc.

<<The object of the MADDEN SYSTEM is to continuously remove a high percentage of foreign solids which accumulate in all boilers due to the evaporative process. The most effective results are obtained when the blow-off pipe is extended into the boiler drum to a point of turbulent flow. Steam bubbles moving upward will carry the suspended solids present to the surface of the water; thus it is desirable to have the blow-off pipe extend inward to, or near, the section of upsurge. In the instance of single drum boilers or others where it is necessary to install continuous blow-off in the same drum with incoming feed water, the blow-off pipe should be located to bleed from a point as far removed as possible from the feed water inlet; otherwise clear feed water, rather that concentrated boiler water, will be removed. Whenever a deflector plate or baffle is installed in the drum, separating the feed water from boiler water, the blow- off pipe should be on the boiler water side of the plate. As a general rule, one pipe connection into the boiler drum is all that is required. The exceptions to the rule are represented by straight tube boilers with more than one drum, boilers with water walls, or others where the construction is such that circulation of water may follow more than one path or cycle.>>

Technical References and Standards

U.S. Department of Energy

<<When people hear about fluid measurement, they usually think of checking either liquid or gas flow. This belief is natural, since about 90% of fluid measurements are for these two applications. In a worldwide survey of flowmeter users, 68% measured liquids, 22% gas, and only 10% steam. While 10% may not seem like a large percentage, it represents a significant number of measurements. Many companies measure steam for purposes of internal custody transfer and for utility applications in power generation and chemical plants.>>

Problems When a Steam Trap Passes Steam

ITT Industries

<<When a trap has failed to the point where it passes steam, it is easy to ignore or place on our never-ending list of ;things to do. After all, what harm is it causing besides wasting a few dollars worth of steam? The process is still being heated. However, a failed trap may be costing you more than just the loss of a small amount of steam. It may be costing you a lot more.>>

Steam Tables

Pump.net

Positioning, Piping, and Trapping for Steam Heating

Paul Mueller Company

What is a Steam Trap?

Carleton University

<<A steam trap is used to remove condensate (water) from the steam lines. The most common type of trap is an inverted bucket trap shown on the left. Steam and water enter at "E" and initially the steam will push the inverted bucket "A" up. When the trap fills with water, the inverted bucket "A" will drop and the water will be blown out into a condensate line at "B". The bucket then rises again and the hole at "B" closes. The cycle repeats itself .>>

How Efficient Is Your Steam Distribution System?

Steam Conservation Systems

<<The purpose of a steam distribution system is to deliver energy from the boiler to where it is needed. A perfect steam distribution system would deliver it without any delivery losses. This would require perfect piping insulation, perfect steam traps and perfect condensate recovery systems, with no maintenance needed. Real steam distribution systems are built of components that decay, and are maintained by human beings. Real systems have losses from less-than-perfect insulation, leaking steam traps, flash steam and dumped condensate. Maintenance is expensive and may be delayed by lack of funds or personnel. The delivery loss of a real steam distribution system is much higher than the zero delivery loss of a perfect system.>>


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