Marine Steam Boiler

Summary

This video offers a comprehensive introduction to water treatment for marine steam boiler systems. It starts with the basics of steam boilers and water chemistry, then delves into issues like corrosion and scaling that can affect boiler systems. Solutions such as correct chemical dosing, control procedures for safe water testing, and tools for troubleshooting are discussed. The video also highlights the advantages of using vertical water-tube boilers on marine vessels due to their compactness and efficiency. Specifics about maintaining boiler water chemistry, such as using oxygen scavengers and alkalinity builders, are covered. Additionally, the importance of proper water testing and recording is emphasized to ensure the longevity and efficiency of marine boilers.

Highlights

• Marine steam boilers require water treatment to handle corrosion and scaling problems. 🌊
• Chemical dosing and water testing are key to boiler care. 🧑‍🔬
• Vertical water-tube boilers are efficient and compact for marine use. ⛴️
• Boiler systems need maintenance with oxygen scavengers and alkalinity builders. 💧
• Regular recording of water tests can prevent future issues. 📋

Key Takeaways

• Marine steam boilers need careful water treatment to prevent corrosion and scaling. 🛠️
• Correct chemical dosing and water testing are vital for maintaining boiler efficiency. 🧪
• Vertical water-tube boilers are preferred on ships for their compact and efficient design. 🚢
• Proper maintenance includes using oxygen scavengers and alkalinity builders. 🧼
• Keeping detailed records of water testing helps in quick corrective actions. 📊

Overview

Ahoy there, marine engineers! This video is a treasure map to understanding the world of water treatment for steam boiler systems. It charts the course from basics of steam boilers and water chemistry to the darker waters of corrosion and scaling, providing you with solutions to navigate around these challenges. With an engaging approach, it emphasizes the importance of proper chemical dosing, monitoring, and testing, all crucial for avoiding a shipwreck of sizzling steam messes!

Ascend to the crow's nest and you'll see the virtues of vertical water-tube boilers, now the flagship choice on many marine vessels. Their compact form and reliable operation are lauded, perfect navigators of the open seas. The video sails through the operational principles transparently, ensuring you understand the role of non-heated downcomers and water circulation used to greet the sea’s demands.

Finally, drop anchor into the technical depths of boiler water chemistry! Discover the necessity of oxygen scavengers and alkalinity builders, the unsung heroes in preventing metal corrosion and unsightly scaling. With a nod to maintaining detailed records, it prepares you to act buoyantly with electronic tools like Waterproof for recording water test results. Keeping your systems tall ship-shape depends on routine checks and corrective actions.

Chapters

• 00:00 - 00:30: Introduction to Marine Steam Boilers and Water Chemistry This chapter serves as an introduction to the course focused on marine steam boilers and water chemistry. It provides a foundational understanding for marine engineers and support staff on the significance of water treatment within steam boiler systems. Initially, the chapter explains the fundamental concepts of steam boilers coupled with essential water chemistry. It then explores the issues arising from corrosion and scaling within these systems and discusses various water treatment solutions available to counteract these problems. Moreover, the chapter covers the critical role of precise chemical dosing and control, including procedures for safe sampling and testing of water. Lastly, it highlights the importance of monitoring water test results and examines the tools used in these procedures.
• 00:30 - 01:00: Steam Boilers and Combustion The chapter titled 'Steam Boilers and Combustion' introduces steam boilers as equipment where water can be fed. It mentions that at the end of the course, a troubleshooting guide is available. The chapter is likely focused on the construction, function, and maintenance of steam boilers, along with discussing aspects of combustion related to their operation.
• 01:00 - 02:00: Types of Marine Boilers The chapter 'Types of Marine Boilers' discusses steam as an effective medium for supplying heat, highlighting its easy transportability through piping to points of use. It provides examples of utilizes steam in various applications. Specifically, it mentions shell and tube boilers commonly found on ships, explaining their structure where water is on the shell side, and heat is generated via a burner firing inside a large diameter furnace tube, with smaller tube banks positioned above.
• 02:00 - 03:00: Operation of Water-tube Boilers The chapter discusses the operation of water-tube boilers, focusing on their use in marine vessels. It begins with an explanation of furnace tubes, emphasizing secondary heat recovery due to their large diameter. The text highlights that the maximum pressure limit for shell boilers is approximately 20 bar, which contrasts with the vertical water-tube boilers. The vertical water-tube boiler is noted as the most common type found on marine vessels due to its compact construction and ease of operation. The chapter sets the scene to explore the principle of operation for these boilers.
• 03:00 - 04:00: Water Treatment and Corrosion in Boilers The chapter provides a detailed explanation of the structural design and functional aspects of boilers, emphasizing the incorporation of a cylindrical shell and hemispherical or cylindrical furnace chamber. It explains how burners fire into the chamber, creating hot gases that pass around the tubes holding boiler water, ultimately exiting through an internal flue to the stack. The water is located on the tube side to accommodate the brief retention time of the hot combustion gases, and the chapter notes that the water tubes can be installed in various orientations, such as horizontally, vertically, or obliquely.
• 04:00 - 05:00: Boiler Treatment Programs and Oxygen Scavengers This chapter discusses the mechanics of a water tube boiler, focusing on how it maximizes heat transfer through the use of cross tubes in the furnace section. It highlights the control of water circulation via non-heated downcomers, which connect the upper steam water chamber to the lower bottom header to enable natural circulation. The chapter also mentions the role of temperature differences in creating this circulation and touches on the maximum operating pressure of the boiler.
• 05:00 - 06:00: Alkalinity and Scale Control in Boilers This chapter discusses the design and operation of water-tube boilers, focusing on the configurations of pipework to maximize heat extraction from the furnace. It mentions common configurations like type O, D, and A boilers and describes the process of feed water being pumped into the boiler and heated by the burner system, leading to increased temperature and pressure as per the boiler's design. The context here applies to boilers typically operating within 10 to 30 bar pressure ranges.
• 06:00 - 07:00: CO2 and pH Control in Boiler Systems The chapter discusses the arrangement of valves in boiler systems to control the flow of steam, which is generated from the headspace above the water level. This steam is used, cooled, and then condensed back into water. The condensate water is typically recovered and recycled as boiler feedwater.
• 07:00 - 08:00: Multifunctional Treatment and Dosing Systems The chapter titled 'Multifunctional Treatment and Dosing Systems' introduces the concept of steam generation on ships using exhaust gas boilers, which are a type of non-fired boiler. These boilers work by circulating water in a large heat exchanger without an external flame to raise steam while at sea. It explains the interconnectedness of fired and non-fired boiler systems on ships and emphasizes that normal water, like tap water, contains various constituents that are important for health. Additionally, the chapter mentions that sea water primarily contains sodium chloride with other significant components.
• 08:00 - 09:00: Water Sampling, Testing, and system control This chapter discusses the importance of water sampling, testing, and system control in marine steam boilers and engine cooling systems. It highlights how the presence of calcium and magnesium salts can lead to operational issues if not removed. Dissolved gases like oxygen and carbon dioxide can cause corrosion, while dissolved salts such as calcium carbonate can cause scale deposition. These issues, if not effectively managed, can pose significant problems, with corrosion being identified as an electrochemical process.
• 09:00 - 10:00: Utilizing Software for Water Test Records The chapter titled 'Utilizing Software for Water Test Records' discusses the process of metal corrosion in the presence of electrolyte water. The transcript highlights how local differences in chemistry, metallurgy, and oxygen concentrations can lead to potential differences on a metal surface, forming a cathode and an anode. At the anode, metal loss occurs, resulting in the formation of iron oxide deposits, commonly known as rust. The chapter further classifies corrosion into two main types: uniform corrosion and pitting corrosion.

Marine Steam Boiler Transcription

• 00:00 - 00:30 This course is designed to provide marine engineers and support staff with an introduction to water treatment for steam boiler systems it begins with an introduction to steam boilers and basic water chemistry the course goes on to look at the problems caused by corrosion and scaling and the water treatment solutions that are available the course examines the importance of correct chemical dosing and control and the procedures for safe sampling and testing there is a section on monitoring water test results and a look at the tools and
• 00:30 - 01:00 service that are available at the end of the course there is a troubleshooting guide a steam boiler is a piece of equipment into which water can be fed the water is
• 01:00 - 01:30 heated under pressure and is continuously evaporated into steam steam is an excellent medium for the supply of heat and can easily be piped to the required point of use click on the question marks for some examples of typical uses for steam shell and tube boilers can be found on ships and are so called because the water is described as being on the shell side of the construction heat is provided by a burner firing inside a large diameter furnace tube a series of smaller diameter tube banks above the main
• 01:30 - 02:00 furnace tube provides secondary heat recovery because of the large diameter of the furnace tube the maximum pressure limit of operation of Shell boilers is around 20 bar vertical water-tube boilers are the most common type of boiler found on marine vessels they're almost exclusively used in the marine industry because of their compact construction and ease of operation let us look at the principle of operation the vertical water tube boiler has a
• 02:00 - 02:30 cylindrical shell and contains a hemispherical or cylindrical furnace chamber at its base the burner is fired into this space and the hot gas is produced pass around a series of tubes containing boiler water and exhaust through an internal flue to the stack here the water is on the tube side of the construction to compensate for the short retention time of hot combustion gases water tubes can be fitted horizontally vertically or obliquely
• 02:30 - 03:00 cross tubes in the furnace section to maximize heat transfer inside a water tube boiler the water circulation is controlled by having a series of non-heated downcomers connecting the upper steam water chamber to the lower ring shaped bottom header the water in the downcomers is cooler and denser than in the hot Rises and this causes a natural circulation of the boiler water the maximum operating pressure can be in the order of a tea
• 03:00 - 03:30 bar but is typically 10 to 30 bar the pipework inside water-tube boilers is configured to extract as much heat from the furnace area as possible common pipework configurations attempt o d and a type boilers in a typical steam boiler system feed water is pumped into the boiler and heat is applied from a burner system temperature and pressures increase according to the boiler design
• 03:30 - 04:00 valve arrangements are used to allow steam to flow in a controlled manner from the headspace above the water level steam flows to the point of use and cools and condenses back to water condensate water is typically recovered and recycled as boiler feedwater once the ship is underway it is usual practice to utilize the heat rejected from the main engine exhaust gas to generate steam this means that the boilers do not need to burn valuable
• 04:00 - 04:30 fuel oil whilst at sea steam is raised by circulating water in a large non fired heat exchanger these types of boilers are referred to as exhaust gas boilers the fired and non fired boiler systems are usually interconnected in general water is never pure normal tap water contains a number of constituents that are important and beneficial to our Constitution the table shows that sea water has a predominance of sodium chloride with significant amounts of
• 04:30 - 05:00 calcium and magnesium salts when introduced to marine steam boilers or engine cooling systems these constituents will cause operational problems if not removed for example dissolved gases such as oxygen and carbon dioxide will cause corrosion and dissolved salts such as calcium carbonate will lead to scale deposition as we will see corrosion and scaling are serious problems if not controlled corrosion is an electrochemical process
• 05:00 - 05:30 where metal in contact with an electrolyte water is oxidized to corrosion products local differences in chemistry metallurgy and oxygen concentrations will induce potential differences on the metal surface and a cathode and anode is formed at the anode will take place and metal will be lost characteristic deposits of iron oxide rust are also formed broadly speaking corrosion can be divided into two types uniform corrosion and pitting corrosion
• 05:30 - 06:00 click on the pictures for more information oxygen chloride salts and pH all contribute to corrosion corrosion in steam condensate systems can be particularly aggressive due to partially wet and hot conditions carbon dioxide and oxygen in the boiler feedwater flashover with steam and rhe dissolve in the condensate water the condensate
• 06:00 - 06:30 water is very pure and has no buffering capacity so relatively small amounts of carbon dioxide will make the condensate water very acidic aggressive corrosion will rapidly deteriorate metal surfaces and lead to pipe work failure and leaks specialized treatments have to be applied to inhibit condensate line corrosion scale deposits are formed when impurities such as calcium carbonate are allowed to enter the boiler due to the negative solubility properties that is
• 06:30 - 07:00 decreasing solubility with increasing temperature of these salts deposition of scale is favored on hot surfaces scale deposits form hard and tenacious layers inside the boiler tubes such deposits will reduce heat transfer efficiency cause overheating and potential tube failure to address the problems of scaling and corrosion a range of water treatment chemical technologies have been developed these are applied to adjust the properties of the feed boiler
• 07:00 - 07:30 and condensate waters and provide protection of the system methyl work a typical boiler treatment program consists of a combination of chemicals in open boiler systems it is usual practice to raise the temperature of the feed water to minimize the level of oxygen present oxygen scavengers are then applied to further reduce the oxygen to sub ppm levels for best corrosion protection there are various types of oxygen scavenger available to
• 07:30 - 08:00 carry out this task and selection of the best approach is a function of the mount of oxygen present feed system design economics and any particular limitations required by the process using the steam some oxygen scavengers such as D ha hydrazine and carbohydrate promote a protective iron oxide film called magnetite that further enhances corrosion protection steel surfaces are best protected in an alkaline environment alkalinity builders are used to increase pH and alkalinity to the desired levels for best corrosion
• 08:00 - 08:30 protection alkalinity builders also help with scale control in alkali phosphate treatment programs the alkalinity of the water also acts as a buffer a property that will absorb pH changes if acid components are introduced and maintain an alkaline pH in alkali phosphate treatment programs soluble phosphate is incorporated into the treatment program to precipitate any trace hardness salts
• 08:30 - 09:00 passing into the boiler and disperse the salts before they can deposit on the heat transfer surfaces scale dispersants are also used to ensure that any precipitated scale salts are maintained free flowing in the boiler water precipitated salts are then removed by routine blowdown this treatment approach relies on good quality pretreatment usually see water evaporators elevated pH and free caustic alkalinity helped the mechanism of precipitation carbon
• 09:00 - 09:30 dioxide is present in most waters and in the boiler system it will evaporate and follow the steam into the condensate system when condensation occurs the carbon dioxide will read azov' and lead to a low pH which consequently causes corrosion neutralizing a means of volatile alkaline materials that flash over with the steam they combined with the condensate water to elevate pH and provide corrosion protection many Marines steam boiler systems operate at
• 09:30 - 10:00 low pressure and run at a steady-state this allows for the application and control of multifunctional treatment products and for small and moderate sized boilers this is the most common treatment approach typical multifunctional treatments are shown here a complete boiler treatment program can be furnished by two or three products whether is variable steam load variable feed water temperature and with high pressure boilers control of the selected water treatment program is best obtained
• 10:00 - 10:30 by dosing product types separately it is best practice to install chemical dosing and control systems for steam boilers click on the question marks to see the benefits of such a system this chart describes how good control of water treatment applications can optimize cost and improve system protection water sampling and testing is used to control the performance of water treatment programs most treatment chemicals have a set of control parameters that should be
• 10:30 - 11:00 maintained for optimum system protection correct sampling frequency and procedures are important to achieve inconsistent results system control parameters should be in line with BS 1170 1983 treatment of water for marine boilers consult your water treatment technical manual for further guidance it is important that test results are recorded both for quality purposes and
• 11:00 - 11:30 to help with the interpretation of trends this enables corrective decisions to be made quickly and effectively water testing is an essential shipboard activity that should be performed on a regular basis water proof is a software package developed to enable the crew onboard the vessels to electronically record store and display results from water tests when entering the test results the user immediately gets notified if the results are within the set limits or if corrective actions are needed the test results can be sent to
• 11:30 - 12:00 Williamson ship service for review this is done via the internet or email a report from our water treatment experts will be returned within days after the defined test period is closed