Showing posts with label boiler. Show all posts
Showing posts with label boiler. Show all posts

Tuesday, March 27, 2018

Steam - Desuperheating and Attemperation

electric power generation plant
Steam is a motive force used to generate electric power
Industrial operations of many types utilize steam as a heat or power source, plus there is electric power generation. Steam is an important sort of "back office" component of the lives of many dwellers in modern economies.
What is steam?
Sorry, but we need to get everybody on the same page here. Steam is water vapor, produced by the application of heat to water. In order for steam to do work and serve as a useful energy source, it must be under pressure. There can be applications that employ steam at atmospheric pressure, but most are pressurized.

The heat goes on, the water boils, steam is produced and flows through the piping system to where it is used. Sounds simple, sounds easy. It is not. There are intricacies of designing and operating a steam system that determine its raw performance, as well as how efficiently it uses the fuel or other heat source employed to boil water. Steam utilization equipment is also carefully designed to provide its rated performance when supplied with steam of a given condition.

Steam at any given pressure has a saturation temperature, the temperature at which the vaporized water content of the steam is at its maximum level. Heat steam above its saturation temperature and you have superheated steam. Cool it below the saturation temperature and vapor will start to condense. The way in which the steam is to be used determines whether, and how much, superheat is desirable or necessary.
  • Turbine operations benefit from properly superheated steam because it avoids exposure of the turbine to liquid water droplets, generally a source of surface erosion and other accelerated wear.
  • Heat exchanger performance is based upon certain inlet conditions, one of which is the degree of superheat.
  • Maintaining sufficient superheat throughout a continuously operating steam system minimizes the need for, and size of, a condensate return system
Processes are designed to deliver a predictable output when provided with known inputs. In the case of steam, the temperature of the steam may be an input requiring control. This brings us to attemperation, which in the case of steam most often refers to lowering the temperature of a steam supply. Attemperation and desuperheating (reducing the degree of superheat) are accomplished in a similar fashion, but with differing objectives. Attemperation involves simply controlling the temperature of the steam, without any direct regard for the level of superheat. Desuperheating, as a control operation, is not directly related to the temperature of the steam, just the degree by which it exceeds the saturation temperature at the current condition. For attemperation, steam temperature measurement is all that is needed. For desuperheating, pressure and temperature measurements are needed. Decreasing the temperature of superheated steam will naturally reduce the amount of superheat.

Some process requirements may focus on temperature of the delivered steam, without regard to superheat level. Others will rely on a specified level of superheat. The application scenarios are vast, with equipment available to accomplish whatever is needed.

Either operation can be accomplished with a specialized heat exchanger or other device that extracts heat from the steam. Another option relies on the addition of atomized water to the flowing steam to manage temperature or superheat level. Share your steam system challenges with steam system experts, leveraging your own knowledge and experience with their product application expertise to develop an effective solution.

Sunday, February 18, 2018

Getting Benefit From Waste Steam With a Thermocompressor

steam thermocompressor
Steam thermocompressor enables use of waste steam
in higher pressure applications.
Image courtesy Spirax Sarco
Steam, with its utilization as a means of transferring heat, as well as a motive force, is found in use throughout many industries. The production of steam is a significant cost of operation for any business where it is employed. Steam, after performing its intended function, still contains a comparatively large amount of heat, so methods of recovering or utilizing that heat energy remaining in waste steam is a positive step in conservation.

Energy conservation and energy efficiency have contributed very large cost savings to many industrial and commercial operations over the past two decades. Projects with modest payback periods quickly contribute to the bottom line of the operation's balance sheet. It is not uncommon for  energy conservation and efficiency measures contribute to improvement in the overall functioning of the steam utilization equipment or systems. In order to save energy, it is generally necessary to exercise better control over equipment or system operation by gathering more information about the current operating state. This additional information, gathered through measurement instrumentation, often finds use in several ways that improve productivity and performance.

A thermocompressor is a type of ejector that mixes high pressure steam with a lower pressure steam flow, creating a usable discharge steam source and conserving, through reuse, the remaining heat content of the otherwise wasted low pressure steam. The device is compact and simple, with no moving parts or special maintenance requirements. Two general varieties are available. A fixed nozzle style is intended for applications with minimal variation in the supply and condition of the suction steam (the low pressure steam). Some control is achievable through the regulation of the high pressure steam flow with an external control valve. A second style provides a means of regulating the cross sectional area through which the high pressure steam flows in the nozzle. This style is best applied when specific discharge flow or pressure is required, or there is significant variation in the inlet steam conditions.

Share your steam system challenges with a steam system application specialist. Leverage your own process and facilities knowledge and experience with their product application expertise to develop effective solutions.


Thursday, December 21, 2017

Capsule Steam Traps

cutaway view capsule steam trap
Capsule type steam trap, cutaway view
Image courtesy Tunstall Corporation
Steam traps are an important part of a closed steam system, directing condensate on a path back to the boiler for reuse and venting non-condensing gases from the system. Of the several different types of steam traps utilized commercially, the thermostatic steam trap is but one. Thermostatic traps are often applied when the application can benefit from a utilization of some of the heat remaining in the condensate. This trap design will hold the condensate in place until it cools sufficiently below the saturation temperature of the steam.

Capsules utilized in thermostatic steam traps contain the controlling elements of the device. The parts are somewhat subject to wear through their movement, but more so from the corrosive effects of system fluid, impurities, and mechanical shock from water hammer. Tunstall Corporation specializes in the manufacture of replacement capsules for thermostatic steam traps that provide better service and extended warranty duration. Their sealed units are fabricated of stainless steel and welded to seal out deterioration due to exposure to steam and condensate. Drop in replacement capsules are available for conceivably every trap manufactured in the previous few decades.

Share your steam system requirements and challenges with application specialists, leveraging your own knowledge and experience with their product application expertise to develop an effective solution.

Friday, August 18, 2017

Thermodynamic Steam Traps

cutaway view thermodynamic steam trap
Cutaway view of disc type thermodynamic steam trap
Image courtesy of Spirax Sarco
Condensate return is an essential operation in any closed loop steam system. Steam that has lost its latent heat will collect in the piping system as hot liquid water (condensate). This liquid needs to be separated from the steam and returned to the boiler feedwater equipment without letting steam escape in the process.

Various items of steam utilization equipment and processes will result in condensate formation at different rates. The device that collects and discharges condensate to the return portion of the system is called a steam trap. There are numerous physical principals and technologies employed throughout the range of available steam trap types. Each has application limitations and strengths making them more or less suitable for a particular installation.

A thermodynamic steam trap relies on the energy provided by the condensate to move a disc which controls the flow of the condensate into the return system. The disc is the only moving part in the device. Condensate flows through a port to a chamber on the underside of the disc, lifting the disc and directing the flow to the return system or drain. Eventually, the fluid flowing into the chamber will reach a point where some of the condensate flashes to steam. A portion of this steam flows through a channel into the space above the disc, called the control chamber. The increase in pressure in the control chamber due to the steam influx pushes downward on the disc, seating it in a closed position. The trap, with the disc seated, remains in the closed position until the flash steam in the control chamber cools and condenses. Then the disc can be opened again by the inflow of condensate.

The thermodynamic disc trap is:

  • Easy to install
  • Compact
  • Resistant to damage from freezing
The single trap can cover a wide range of system pressure, and the simple construction translates into low initial cost. Properly matching any steam trap to its application is important. Share your condensate return and steam system challenges with specialists, combining your knowledge and experience with their product application expertise to develop effective solutions.



Friday, July 21, 2017

Pressure Motive Condensate Pumps



In a closed steam system, condensate must be returned to the feedwater side of the boiler. Moving this condensate effectively through the system is essential to maintaining design performance levels throughout the system. Condensate can be considered "spent steam", but still retains great value as preheated and treated feedwater for the boiler.

Three general methods are employed to transport condensate from where it is collected to where it is reused. If the facility layout permits, gravity can be the motive force to move the condensate back to the boiler. A second option is a mechanical pump, unsurprisingly called a condensate pump. The third common option is to employ system steam pressure to drive the condensate through the return piping and back to the boiler.

The concept of gravity return for the condensate is easy to envision....liquid flows downhill. Mechanical pumps, as well, are a well understood means of moving liquids. When the condensate collector reaches a certain fill level, the pump is energized and the liquid is forced through the return piping.

Using pressure as the motive force for condensate return involves coordinated operation of inlet, outlet, and vent openings to the condensate collection vessel. A float inside the collection vessel and a connected mechanism provide control of the valves at the vessel openings. In the video, you can see how the valve operating sequence provides for periods of condensate collection, then condensate discharge.

Share all of your steam system challenges with application specialists, combining your own process and facilities knowledge and experience with their product application expertise to develop effective solutions.

Thursday, June 29, 2017

Sterling Condensate Return and Steam Control Equipment



Sterling, under the Sterlco brand, manufactures a range of Steam control products for commercial and industrial use. Steam traps, condensate return pumps, boiler feed pumps, and self regulating temperature control valves are all part of the product offering. The video included with this posting provides a short overview of the product extent of the Sterlco line.

Share your steam system challenges with product application specialists. Combine your own facilities and process knowledge and experience with their product application expertise to develop the  most effective solutions.

Tuesday, May 2, 2017

Steam Traps

high pressure float type steam trap cutaway view
Cutaway view of high pressure float type steam trap
Courtesy Spirax Sarco
Steam is widely used throughout industrial, commercial, and institutional facilities and a means of transferring heat energy, as well as a wide array of other applications. Steam generation cost is a substantial line item on almost any balance sheet, so deriving the most efficient level of operation from a steam system pays tangible dividends.

Utilizing the heat content of steam, in a closed system, results in the production of condensate. Condensate is hot liquid water which can be returned to the boiler and re-vaporized. Managing the separation of the liquid condensate from the process steam and sending it to the lower pressure condensate return line is the function of a steam trap. A steam trap filters out condensate (condensed steam) via an automatic valve. The trap also removes air without letting process steam escape. By filtering out the condensate and not the steam, steam waste is minimized. Steam traps generally are self-contained automatic devices. Since steam based heating processes generally rely on latent heat transfer for rapid and efficient operation, it is necessary to continually collect and transfer condensate from the steam containing portion of the system. The condensate will reduce heat exchanger performance if allowed to accumulate.

Historically, there have been three main types of steam traps: mechanical traps, thermostatic traps, and thermodynamic traps. Most commonly used mechanisms rely on differences in temperature, specific gravity, and pressure. The mechanical trap was originally developed as a bucket trap, which was a rather large trap where a bucket floated up or down to open and close a valve. Bucket traps with a lever, which face downward – also known as ‘closed bucket’ traps – are still used today as a float type trap. Processes requiring large capacities for discharge still currently use the bucket type or float type trap, with long services lives. In the modern version of a free float trap, the condensate is continuously discharged while the valve opening is constantly controlled by the amount of buoyant force acting upon a tightly sealed float.

Thermostatic traps are a smaller, more compact design. Using a temperature sensing mechanism, and operable by mechanisms like bellows or bimetal rings, these thermostatic traps have a slower response. Processes relying on rapid condensate discharge most likely will not use thermostatic traps. An example of a trap used in the process industry today is a bimetal temperature control trap. The trap includes steam tracers and will discharge when a certain condensate temperature is reached.

The core limitation of thermostatic steam traps – the slow response time – has been addressed via the development of the thermodynamic steam trap. The thermodynamic trap operates on the expansion and contraction of an encapsulated liquid. This version of steam trap allows for the smallest amount of condensate accumulation. Early models resulted in unacceptable levels of steam loss. As a result, the commonly used disc type trap was developed for mainstream use. The disc type is compact, versatile, and relatively affordable in terms of installation costs. In the modern disc type, pressure fluctuations in the chamber above the valve result in the valve’s opening and closing. Though in use for many years, development and refinement continues on steam traps, bringing ever better performance to this ubiquitous steam specialty.

Share your challenges with a steam system specialist, combining your own process and facilities knowledge and experience with their product application expertise to develop effective solutions.

Wednesday, January 18, 2017

Mountain States Engineering and Controls Expands Product Offering

duplex condensate return pump with receiver tank and sight glass
Duplex condensate return pump
Courtesy Sterling Sterlco
Mountain States Engineering and Controls has added the Sterling Sterlco line of condensate pump, boiler feed pump, and temperature control valve products to round out its comprehensive offering of instruments and equipment for steam systems and process cooling.

The Sterlco condensate pumps are available in simplex or duplex configurations, with pump and receiver capacity ratings to accommodate a broad range of industrial and commercial applications. Option selections round out the flexible product specification.

Boiler feed pump units from Sterlco provide a similar extensive range of receiver and pump capacities, along with options to meet application specific requirements.

The Sterlco self powered modulating temperature control valves are available in eight sizes and provide regulation of coolant flow to a machine or process. Their simple design provides rugged temperature actuated performance in a wide array of cooling applications.

There is more to learn about Sterling Sterlco condensate pumps, temperature control valves, and boiler feed pumps. For the latest product information, or to work on a solution to your steam or cooling system challenges, reach out to an application expert and combine your facilities and process knowledge with their product application expertise to develop effective solutions.



Monday, January 2, 2017

Steam Trap Maintenance Made Easier With Pipeline Connector

steam trap isolation valve set
PC4000 Pipeline Connector
Courtesy Spirax Sarco
Steam is a common source of heat or power throughout industrial and commercial installations. Most steam systems operate as a closed system, with return of condensate to maximize energy efficiency and gain other operational benefits. Steam traps are the workhorse of many condensate return systems, routing condensate back to the boiler and non-condensible gases out of the system, all without a major loss of steam.

Steam traps are points of high maintenance in the steam system. They are also an integral part of the system, meaning they are under pressure. Steam trap maintenance requires isolating the trap from the system, venting the pressure within the isolated section, and removing liquid that may be contained in the trap.

Spirax Sarco, globally recognized leader in steam system componentry and controls, provides a single unit solution for steam trap maintenance isolation. The PC4000 pipeline connector series (in the company's own words)...
"...are a complete 'Trap valve station solution' developed for use with two bolt universal swivel connector steam traps.
As the unit has been designed with two integral piston stop valves, it is possible to isolate both upstream and downstream of the universal trap connection and through the use of the fitted depressurization valves, possible to depressurize, test and drain the pipeline. The trap depressurization port also incorporates a maintainable 40 mesh stainless steel strainer screen to provide trap protection from system dirt and debris, which can be cleared through the use of the line pressure."
 A detailed data sheet is provided below for further review. Share your steam system challenges of all types with specialists, combining your facility and process knowledge with their product application expertise to develop effective solutions.


Tuesday, November 1, 2016

New High Pressure Float Type Steam Trap

steam trap high pressure float type
Model FTC62 High Pressure Steam Trap
Courtesy Spriax Sarco
Steam is utilized by industrial operations as a source of heat and power. Commercial and institutional facilities widely employ steam as a heating source. The overall cost of operating a steam system is generally significant, regardless of the size of the organization. Designing a system to deliver efficient performance and maintaining that performance throughout many years of expected operation requires continuous monitoring and attention.

One facet of efficient operation is to remove condensate from the steam system and return it to the boiler. This operation is the primary function of a steam trap. Additionally, a steam trap will also remove non-condensible vapor from the system. Liquid water and non-condensible vapor both will undermine efficiency in a common steam system.

There are many versions of steam traps available, and it is important to match the capacity and performance range of the trap to the steam system. Spirax-Sarco, globally recognized steam system specialties manufacturer, has added  a new steam trap model series to their already extensive offering.

The FT62 Series, which is available with a carbon steel (FTC62) or stainless steel (FTS62) body, has stainless steel internal components. It is intended for application on light and heavy condensate loads on steam systems with differential pressure up to 900 psig (62 bar).  The unit includes an integral air vent and an easily maintainable in-line strainer.

More information is provided below, with good illustration of the exterior and interior setup of the steam trap. Share your steam system requirements and challenges with experienced application specialists, combining your facility and process knowledge with their product application expertise to develop effective solutions.


Tuesday, October 18, 2016

Knowledge Base for Steam System Components

steam system schematic showing area of steam utilization
Steam utilization schematic showing array of products (blue)
Spirax Sarco
Steam, ubiquitous source of industrial power and commercial heat, ranks as a substantial continuing expense item for any organization where it is utilized or produced. Designing, installing, and managing steam system operation effectively can generate immense cost savings over less rigorous approaches.

An effective method of good decision making involves tapping into the experience and expertise of those that have gone before, accomplished what you plan to attempt. For steam systems, Spirax Sarco is a premiere source of information, knowledge, and expertise. The company has been deeply involved in the production and utilization of steam for many years, designing and manufacturing components utilized throughout the entire process.
steam system schematic showing components utilized in production of steam
Steam production schematic showing array of products (blue)
Spirax Sarco
In the steam generation section of an operation, the company provides a extensive array of interrelated products.
  • Blowdown Heat Recovery Systems
  • Blowdown Vessel
  • Boiler Feedtank Systems
  • Boiler Level Controls and Alarms
  • Bottom Blowdown Valves and Systems
  • Condensate Contamination Detection
  • Electrically Actuated Two Port Control Valves
  • Pipeline Strainers
  • Sample Coolers
  • Safety Valves
  • Spirax Range of Flowmeters
  • Steam Trap Performance Monitoring
  • Tank Level Controls
  • TDS Control
  • Vacuum Breakers
Throughout the balance of the steam system, the list of components available from the company expands even more, illustrating Spirax Sarco's depth of knowledge about steam system components and how they function together to deliver efficient and safe steam system operation.

Reach out to experts with your steam system challenges, combining your facility and process knowledge with their product application expertise to develop effective solutions.

Tuesday, August 9, 2016

Methods of Measurement For Boiler Drum Water Level

gas fired boilers in boiler room
There are numerous boiler water level measurement methods
Steam boilers have a long history in commercial, industrial, even residential applications. The steam they produce can be used to deliver heat, or to drive mechanical equipment and other processes. Maintaining the right boiler operating conditions is essential to safe operation and achieving the best use of fuel.

Boiler water level measurement is one of the essential elements of proper operation. Accurate and effective level measurement will indicate water levels that are too high or too low, both of which can have negative impact.

Spirax Sarco, a globally recognized leader in the development and production of steam related specialties, has developed content that summarizes various methods and technologies used to measure water level in boilers. Each is described in detail, with explanations of the technology, including some mathematical formulas. The piece is well illustrated and some advantages associated with each method are included. The document is from the company's website, under the Resources > Steam Engineering Tutorials section and provided in its entirety below.

Share your steam related challenges with a Spirax Sarco representative, specialists in helping achieve maximum performance from steam systems.



Tuesday, May 24, 2016

Understanding Condensate Pumps on a Steam Distribution System

industrial steam system
Diagram of industrial steam system
(courtesy of Watson McDaniel)
condensate pump is a specialized device intended for use in transferring condensate (water) produced in an industrial steam system. Condensate from a heating system or process is collected, then pumped to the condensate return system, where it is routed back to the boiler for reuse.

In certain cases, the steam pressure of the system may be sufficient to push the condensate through the steam traps and condensate return lines, back to the condensate holding tank in the boiler room. In most practical situations, however, one or more condensate return pumps are required to assist in overcoming gravity, pressure drops from long piping runs, and back pressure in return lines.

Condensate Return Pumps are either electrically-driven centrifugal pumps or non-electric mechanical pumps that use steam pressure as the motive force to pump the condensate. Non-electric pumps are referred to as Pressure Motive Pumps (PMPs).

A facility will often have a separate area that contains various components required for the generation of steam, such as a boiler, condensate holding or deaerator (DA) tank, boiler feed pump, water treatment, etc. Regulated by the boiler control system, the boiler feed pump sends condensate from the holding tank back to the boiler.

Pressure Motive Pumps (PMPs) are non-electric pumps which return condensate back to the boiler room; using steam pressure as the motive force. PMPs can be supplied as stand-alone units – which include a pump tank, the internal operating mechanism, and a set of inlet and outlet check valves, or: as a packaged system – which also includes the vented receiver tank (to collect the condensate) mounted on a common base.

The following is a comprehensive document, courtesy of Watson McDaniel, that provides a good general understanding of steam and condensate systems, traps and condensate pumps. 



Wednesday, October 21, 2015

What You Should Know About Industrial Steam

Electric power generation plant
Electric Power Generation Plant
One of many industrial and commercial uses of steam.
Steam has been an important part of industrial operations since long before your parents were born, and not just for electric power generation. The staying power of steam for commercial and industrial operations stems from its use as a delivery medium for power, heat, and moisture. Today, other than for power generation, steam is frequently used as a method of delivering heat. That, and a range of other uses throughout industry mean that your familiarity with the various elements of a steam production and delivery system are a key part of your personal knowledge base. Your understanding of the basics will serve you well in planning sessions, project discussions, and decision making throughout your industrial career. Even if you are not an engineer, do not carry a tool bag, and only wear a hardhat when you visit the plant floor, knowing about steam systems can boost your decision making skills and confidence on projects where steam is employed.

Spirax Sarco, a world class manufacturer of products and turnkey solutions for the control and efficient use of steam for industrial and commercial users, has produced a set of tutorials that allow you to learn about a wide range of topics directly related to the production and use of steam in industrial and commercial settings. The tutorials are grouped in major sections, with subtopics dividing each subject into smaller parts, making it easy to find a specific topic or break your knowledge gathering operation into more manageable pieces. Major topics include:

  • Introduction
  • Steam Engineering Principles and Heat Transfer
  • The Boiler House
  • Flow Metering
  • Basic Control Theory
  • Control Hardware: Electric/Pneumatic Actuation
  • Control Hardware: Self-acting Actuation
  • Control Applications
  • Safety Valves
  • Steam Distribution
  • Steam Traps and Steam Trapping
  • Pipeline Ancillaries
  • Condensate Removal
  • Condensate Recovery
  • Desuperheating
  • Equations
Few of us will want or need to get through all of it. This is, however, and excellent resource for stakeholders that want to have a bookmark where they can build or refresh their knowledge about the subject. You can gain access to the tutorials through contact with a sales engineer, another valuable resource you should employ in seeking industrial process control solutions.