PRESSURE RELIEF VALVES
Chemical Engineering Lab I
Question: Discuss the importance of Relief Valves in the unit operations in detail, and give the design criteria/ parameters/ models available equations in the literature. Support your work by giving a typical example from the literature.
INTRODUCTION
Since the inception of pressurized systems to produce and transmit energy, it has been a constant goal to find safe, dependable means of relieving pressure. The simple, inexpensive, spring loaded relief valves has been manufactured for over a hundred and fifty years, performing its job with varying degrees of reliability over that time period.
In the Unites States alone, boiler explosions caused a significant loss of life reaching a peak with 400 such explosions in 1904. With the adoption of the ASME Pressure and Vessel Code in 1911, boiler explosions declined to where, after 1973 they are non-existent. Over the same period, operating pressures for most systems were increased, in the case of boiler pressures increases were from 200 to 3000 psi and above.
Pressure relief valves are used to safely contain pressurized gases and liquids. Throughout the years there has been an increased demand for safety in industrial and other related operating practices. These valves are one of the many devices that have been created in conjunction with standardized design and operating practices, for the provision of this very protection. In the past, vessels that now would obviously require relief valves were heated often resulting in drastic increase in pressure within the vessel. This resulted in an extremely dangerous outcome physically for all the parties involved.
Pressure valves may be classified into two main categories namely reclosing and non-reclosing. Reclosing devices are the more common of these two groups. They are designed in such a manner that they reclose securely once safe pressure levels have been restored. The second type, the non-reclosing pressure valve, does not reclose nor vent all the fluid built up, for example fusible plugs.
Pressure relief valves are relatively simple pieces of equipment. The operation of these devices involves a spring-loaded disk resting on a seat. When the pressure is low the force on the disk is less than the spring force on the disk and the valve remains closed. The pressure force increases causing a drop in the force that seals the disk on the seat. Once the valve is raised a larger disk area is available for the fluid to flow through providing a lifting force which is directly correlated.
estimate how much pressure boilers could withstand. They didn't always estimate correctly, as explosions were common. It was expensive to build and maintain the nineteenth century steamboats.
The Split Hopkinson Pressure Bar is named after Bertram Hopkinson [2], who in 1914 acquired a technique to evaluate the pressures created by dynamic events such as the blast caused by a rifle bullet or the explosion of explosives. In this placement, a long cylindrical bar of steel is suspended horizontally by four equal threads so that it can dangle in the vertical plane parallel to it. A short piece of rod of the same diameter is obtained against the long bar by magnetic attraction created by a solenoid. A rifle bullet is forced out or gun cotton is detonated near the close of the long bar. This creates a pressure wave which goes from the long bar in the short piece of rod. On passing the loose end of the short rod the pressure wave is reflected back as a tensile wave; when the magnitude of the tensile wave exceeds that of the pressure wave at the butted end of the short rod, the inability of the short rod to hold up the tension along the joint produces separation and it flies away. The little rod is caught in a box suspended in
...fficult to summarize the operations of such a large corporation, but during this report it has been achieved. The reader will be able to understand how one of the leading groups of engineering and construction companies in the world has achieved such a status. Through a brief analysis and explanation of the history, its competitors, its organizational management activities and an evident problem with its solution can the reader fully understand such a complex and active corporation. But being such an active and international corporation, such problems will and do arise. Such a problem in this report is the outflow of many potentially dangerous process fugitive emissions. This significant and imperative problem and be solved by the either switching suppliers of the pipe work or various other components where there are leaks or to implement some sort of software to detect the location of any leaks so they can be repaired quickly. This major problem must be solved quickly and in a cost efficient manner. This report discusses the methods and activities involved in SNC-Lavalin in a professional, yet straightforward manner so all readers can grasp such an interesting Canadian company.
The automatic fire sprinkler system was one of the earliest sprinkler systems placed into effect. The origin of the modern day automatic sprinkler system dates back to the early 1800’s. The first automatic sprinkler system was created in England in the 1806 by John Carey. It consisted of a pipe with valves held closed by counterweights attached by string. When flames burned through the string the counterweight dropped to the floor, which opened the valve that released the water and extinguished the fire. As the 1800’s progressed, the basic pipe system for sprinklers was becoming more prevalent across England. It began to pop up in textile mills all through out the country. In 1864, as sprinkler system use grew, Major Stewart Harrison of the 1st Engineer (London) Volunteers invented the first automatic sprinkler head. A few years later two gentlemen by the names of Henry Parmelee of Newhaven, Connecticut, and Frederick Grinnell of Providence, Rhode Island, added to the sprinkler head to give it a more practical application. Parmelee took the automatic sprinkler head and added to it a fusible link that broke at about 160oF. This allowed the system to control which heads broke so the whole system wouldn’t drown the whole structure in water, it would only release where there was sufficient heat to break a head. Grinnell invented a head that could withstand higher water pressures without break as well as distribute water more evenly. Each of these inventions increased the efficiency of the systems greatly. Now in today’s modern fire protection era, automatic sprinkler systems are used to protect everyday buildings around the world. It is most commonly in commercial use buildings. This includes but is not limited to schools, hospitals, ...
Was it extraterrestrials, or was it just from a natural cause? Methane bubbles could of bubbled up from a fissure on the seafloor and poisoned the crew. An unobserved fire or failure in the boiler room may have caused all of the deaths. Carbon monoxide from the boiler room could of leaked out causing the deaths of the crew, eventually igniting the explosion. The most confusing part of this incident is why there are 2 dates surrounding the event.
BP turbulent history can be considered the impalement to the current safety and operational procedures. BP had emphasized personal safety and improvements, but the company had a personal injury rates that accounted for 95% of the injuries related to the oil industry. Following the Gulf oil spill disaster, a number of safety recommendations were endorsed by the Bureau of Safety and Environmental Enforcement. It was then BP realized the future of the company was in its on hands and possibly sealed, if they didn’t address the much needed safety and operational procedures. The organization had a clear understanding
One of the most significant environmentally damaging instances in history was the Chernobyl incident. In 1986, the Chernobyl Nuclear Plant in Ukraine exploded. It became one of the most significant disasters in the engineering community. There are different factors that contributed to the disaster. The personnel that were tasked with operating the plant were unqualified. The plant’s design was a complex one. The RBMK reactor was Soviet design, and the staff had not be acquainted with this particular design. As the operators performed tests on the reactor, they disabled the automatic shutdown mechanism. After the test, the attempt to shut down the reactor was unsuccessful as it was unstable. This is the immediate cause of the Chernobyl Accident. It later became the most significant nuclear disaster in the history of the
The Piper Alpha, was an offshore oil production platform that was located in the British sector of the North Sea. It was operated by the Occidental Petroleum Caledonia Ltd. Piper Alpha at the time accounted for approximately ten percent for all gas and oil that was produced from the North Sea (Konard, 2011). Initially Piper Alpha started as an oil platform but later on it was converted to gas production. On the 6th of July 1988, a catastrophic explosion killed 167 men and incinerating the platform causing a damage bill in excess of 3.4 billion U.S dollar. Piper Alpha is the greatest engineering disaster to date. It represent everything that can go wrong due to maintenance errors, causing the worst possible outcome, the loss of many human lives. However, it is essential to understand Piper Alpha disaster was not caused by a singular problem or person, but rather many causes that worked together to create the disaster.
in a flap-type pneumatic check valve air enters from the left port of the check valve and compresses a light spring and forcing the check valve open and allowing air to flow out of the right port. But if air enters from the right air pressure closes the valve, preventing a flow of air out from the left port and a pneumatic check valve is a one-direction flow control valve.
The high pressure liquid refrigerant passes through the expansion valve and becomes a low temperature,
This similar to hydraulic lifting mechanism,it also consists of cylinder & piston arrangement .The difference is just that it uses air as pressurizing medium instead of the hydraulic fluid.
In the early 1900s industrial accidents were commonplace in this country; for example, in 1907 over 3,200 people were killed in mining accidents. At this time legislation and public opinion all favored management. There were few protections for the worker's safety. Today's industrial employees are better off than their colleagues in the past. Their chances of being killed in an industrial accident are less than half of that of their predecessors of 60 years ago. According to National safety Council (NSC), the current death rate from work-related injuries is approximately 4 per 100,000, or less than a third of the rate of 50 years ago. Improvements in safety up to now have been the result of pressure for legislation to promote health and safety, the steadily increasing cost associated with accidents and injuries, and the professionalization of safety as an occupation. When the industrial sector began to grow in the United States, hazardous working conditions were commonplace. Following the Civil War, the seeds of the safety movement were sown in this country. Factory inspection was introduced in Massachusetts in 1867. In 1868 the first barrier safeguard was patented. In 1869 the Pennsylvania legislature passed a mine safety law requiring two exits from all mines. The Bureau of Labor Statistics (BLS) was established in 1869 to study industrial accidents and report pertinent information about hose accidents. The following decade saw little progress in the safety movement until 1877, when the Massachusetts legislature passed a law requiring safeguards for hazardous machinery. In 1877 the Employers' Liability Law was passed. In 1892, the first safety program was established in a steel plant in Illinois, in response to the explosion of a flywheel in that company.
Another condensing steam turbine system known as extraction condensing steam turbine which can provide exhaust steam to the process or feed water heating owing to extra opening in the housing. Depending on the specific demand of steam
As the piston rises, the pressure forces the poppet valve closed, and the mixture is compressed. Once the piston reaches its peak, the spark plug fires, igniting the compressed fuel causing the fuel to expand driving the piston downward. The exhaust valve opens after the piston reaches its lowest point. As the piston begins to rise, the exhaust fuel is driven out of the chamber. Large four-stroke engines tend to have more than one cylinder and often feature valves, fuel injectors, and turbochargers (Four Stroke
Water tap has become an important part for household, business, and also buildings. Modern water tap nowadays are well engineered and can long last but depend on the types of the materials. Many people would prefer to replace the design when remodeling. There are many reasons that causes failure modes for water tap.