журнал для КР по англ

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component.As most machines are part of a process, the process has to be started and stopped many times to achieve the proper balance level. Imagine having to ask the operator of a nuclear facility run the fuel rods in and out a half dozen times or so over the course of four or five days so that you could accomplish something that should have been done off site, in a controlled setting, with proper equipment, during the outage cycle. To make the situation a little more uncomfortable, field balancing forces the user to adjust the rotor response to correct the combined effect of all the non-rotating items (such as misalignment, foundation resonances, piping resonances). If a rotor runs in its casing with undesirable vibration levels after being balanced at-speed it is probably not a rotor issue. A system issue will require further investigation and correction.

Acceptable levels of unbalance

Zero unbalance would always be preferred and many engineers will discuss the acceptable level for hours, given that zero is seldom economically achievable, a common level is chosen using industry standards for various types of machinery. For at-speed balancing, the American Petroleum Institute (API) requires vibration levels less than the greater of 1mm/sec, or 7400rpm.

An investment that pays well

There is rarely a more uncomfortable time in the professional life of a rotating equipment engineer, maintenance manager, or operations manager than when a critical part of their process fails to start on time, will not run, or becomes unreliable between maintenance cycles. The costs of trying to correct the issues, while accounting for lost production, can be quite staggering. Sulzer's dynamic fieldbalancing methods save both time and money over conventional site methods.

Shaun West

Sulzer Turbo Services Zürcherstrasse 12 8401 Winterthur Switzerland

Phone +41 52 262 34 44 shaun.west@sulzer.com

In most cases, the liquid entrained in a gas flow is in the form of droplets. The formation and the size of the droplets are determined by the process application . In counterflow processes, such as distillation and absorption columns, the gas and liquid phases are brought into intensive contact with each other to ensure maximum mass transfer between the two phases. Structured packings, random packings, and trays from Sulzer Chemtech are optimized to increase both mass transfer and product throughput. However, one inescapable disadvantage of promoting contact

Expected droplet size in typical processes

Droplet diameter (microns)

between gas and liquid phases is that this process can frequently lead to liquid being entrained into the gas flow in the form of droplets. In other processes, free liquid is formed in the gas by condensation. In this case, the generation of the droplets and their size is based on a process of nucleation, which can result in the formation of ultra-fine droplets that can be many times smaller than the droplets generated by the entrainment of liquid in counterflow columns. Liquid droplets are never all of the same size but occur in a range of sizes that may often be characterized mathematically by means of curves of log-normal distribution or Gaussian normal distribution.

The new mist elimination technology

The MKS Multi Cassette was developed with the aim of combining high liquid separation efficiency and high capacity with optimal economy. These demands required new ideas and approaches, which were put into practice in the latest mist eliminator product from Sulzer, the MKS Multi Cassette.

The MKS Multi Cassette consists of an inlet tube with built-in swirl element (cyclone) and the succession of separating cassettes mounted above it . The inlet cyclone swirls the gas, thereby causing some of the droplets to be separated on to the inner wall of the cyclone: this

liquid is collected in the bottom cassette, from where it is drained. After the cyclone, the gas, still carrying the remaining entrained droplets, is distributed over the cassettes, flowing through them horizontally from the inside outwards. Each cassette is equipped with several layers of wire mesh packing which efficiently separates the remaining droplets by both direct interception (barrier effect) and inertial interception. The liquid is collected on the tray of each cassette and drained down to the next cassette by a piping system. Finally, all the liquid is collected on the bottom tray, which also

Cut-out drawing of an MKS Multi Cassette™.

Swirl tube

Drain pipe

Swirling elements

Vapor carries mist

CFD simulation with gas streamlines.

acts as support plate for the MKS Multi Cassette, and is then drained downwards out of the device through pipes. The development of the MKS Multi Cassette was supported by computational fluid dynamics simulations (CFD). The simulations performed by Sulzer Innotec enabled development engineers to check and optimize the geometry of the cyclone and the resulting gas distribution to the cassettes .

Application in gas drying columns

The drying of natural gas in glycol dehydrators is a widely used process that is applied in almost all natural gas production plants in the world. Contact between the wet natural gas and glycol (often triethylene glycol, TEG) in the absorption column removes the vaporized water from the gas. Today, the use of high-capacity packing such as Sulzer MellapakPlus in absorption columns is preferred, in order to obtain minimal

column diameters or simply to maximize the natural gas throughput of the unit. Depending on the actual capacity in the column and the physical properties of the glycol, a varying amount of glycol is entrained in the gas. The droplet size in this case can be in the range of 5–25µm. To minimize the carryover, a glycol mist eliminator is required at the top of the column in order to satisfy the stipulated standard of no more than 13.7 liters loss of glycol per million standard cubic meters of gas (0.1 USgal/MMSCF). This loss expressly concerns only the glycol present in liquid form. A column equipped with Sulzer MellapakPlus™ packing requires a suitably sized highcapacity mist eliminator, since otherwise the required gas flow rate cannot be attained .

The MKS Multi Cassette mist eliminator ideally combines with Sulzer MellapakPlus in glycol dehydrators. It meets the following outstanding qualities:

•High separation efficiency

•High capacity

•Excellent economy

•Small installation height

•Simple design

•Easy installation

•Easy maintenance

Its reliability and other qualities have already been proven in many natural gas drying columns.

Application in separators

Columns (separators) having the exclusive function of separating liquid from gas streams are used in many processes. The separation of hydrocarbon liquids from natural gas under high process pressure is always a challenge for mist

Dry natural gas

Lean TEG

Rich TEG

Wet natural gas

Liquid collected at the gas inlet

eliminators. In many cases, the cause of moisture formation is an upstream condensation process: since the surface tension between the gas and the liquid is sometimes low, very small and unstable droplets can be generated. Up to now, if the separators have to be designed for high gas flow rates or simply to save as much space and weight as possible, mist eliminators based on axial cyclones (Shell Swirltube) or vane packs (Sulzer Mellachevron) are used. However, vane

MKS Multi Cassette ™.

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Glycol natural gas drying column with MellapakPlus™ and MKS Multi Cassette™.

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pack mist eliminators are generally not recommended for high-pressure applications with liquids containing hydrocarbons and tend to have relatively low separation efficiency. Axial cyclones, like Sulzer’s Shell Swirltube, are often the first choice and are optimally designed for these tough conditions, but they also require a higher minimum available installation height in the separator. When converting separators to higher capacity, the available installation height is often limited. Also, modifications inside the column can be restricted because, in general, no additional attachments can be welded directly to the column wall.

Revamp of a KO drum to increase capacity

A revamp required the installation of high-capacity separators. However, the available installation height in the separator did not permit the installation of a Shell Swirltube with KnitMesh coalescer without major structural

modifications. The installation of a Mellachevron mist eliminator would also lead to considerable structural complications, because only the vane pack types that approximate the required separation efficiency can be considered for this application. In the end, the customer opted for the installation of the Sulzer MKS Multi Cassette, because this solution combines all the desired advantages in a single product .

With the MKS Multi Cassette mist eliminator, Sulzer provides an optimal addition to the category of high-capacity mist eliminator internals. Its reliability and performance has already been demonstrated in numerous installations of natural gas dehydrators and separators. With the new MKS Multi Cassette mist eliminator, Sulzer Chemtech can offer its customers even better and more specialized custom solutions for highly complex gas-liquid separation processes. Sulzer Chemtech can also assist you in installation and commissioning.

Sulzer MKS Multi Cassette™ for installation in a knockout drum (KO drum: A separator for removal of liquid from gas streams).

Daniel Egger

Sulzer Chemtech AG Sulzer-Allee 48 8404 Winterthur Switzerland

Phone: +41 52 262 50 08 daniel.egger@sulzer.com

© Vitaliy Hrabar, 2009 Used under license from Shutterstock.com

Gas station with several separators.

A history of surface technology

Today's Sulzer Metco division has evolved from a number of different companies. However, a part of the roots of the company are in Winterthur.

In 1968, a small team of researchers began investigating the application of coatings using chemical vapor deposition (CVD) and thermalspraying techniques. Sulzer Metco now operates globally and offers thermal-spraying and thin-film processes as part of its portfolio of surface technologies and solutions for clients in the aviation and automotive industries, power generation, and other specialized markets.

One of the first thermal-spray equipments of Switzerland.

The low-pressure thermal-spray equipment allows the coating of turbine blades.

In 1968, a team led by Hans Beutler commenced work in a new research facility—the Laboratory for New Materials. Its mandate was to develop processes to better protect surfaces against wear and corrosion and to employ new materials—such as those used in the construction of aircraft and rockets—in Sulzer products.

A superior coating

The main driving forces behind their work were the need to find better coatings for thermal turbo machines and the need to meet requirements in the fields of nuclear energy and weaving machines. The research activities focused on the CVD process, the thermal spraying of coatings, and tribology. Since it was possible to conduct several trials per day, thermal-spraying techniques developed

more rapidly than CVD, which could only process one batch daily. In the early 1970s, intensive work was carried out in conjunction with BBC (now ABB/Alstom) to develop high-tem- perature corrosion-resistant coatings for gas turbines. The plasma coating known as SS14 that was developed by the New Materials team was superior to all others. The coating of gas turbine blades was an important step forward that significantly influenced the success of Department 15 (now Sulzer Innotec) in the years that followed.

Founding of companies and acquisitions

The firm Plasmatechnik AG was founded in Wohlen in 1970, at around the same time that Sulzer in Winterthur was taking its first steps in the field of surface technology. Working in close cooperation with Sulzer, Plasmatechnik AG developed sophisticated and highly efficient plasma spray systems with a high production capacity and low rejection rates. The company was taken over by Sulzer in 1985 and subsequently integrated into the group.

In 1986, Sulzer acquired the Michiganbased firm AMI. As a result of this move, Sulzer not only expanded its product range to include spray materials and brazing but also strengthened its profile

and positioning in the USA. In 1991, the Californian company Electro Plasma Inc. was taken over by Sulzer. In the late 1970s, its owner Erich Mühlberger— the American pioneer of plasma spraying— developed the MCrAlY alloys that could be used for stationary gas turbines.

In 1994, Sulzer purchased the Metco divison of Perkin Elmer which was headquartered in New York, and combined all its companies that were active in materials and surface technologies under the name Sulzer Metco. Metco had been founded in 1933 in the USA—at the height of the Great Depression—by a graduate of the California Institute of Technology. The company, which started out with five employees, had developed into a global organization by 1994. Further acquisitions have included: Salzgitter AG in 1995; QCoat Ltd. in 1998; Eldim BV and Interturbine Coatings BV in 2000; Metaplas-Ionon GmbH and EuroFlamm GmbH in 2001; Euroflamm Select Inc. and DB Thin Filmx LLC in 2002; as well as WOKA GmbH, Ambeon, and OSU Maschinenbau GmbH in 2004.

Today, Sulzer Metco offers a broad range of surface technologies, which, combined with its experience, offer customers the very best surface solutions.

Gabriel Barroso

Sulzer Metco offers not only products but also complete solution packages to its customers. This

added offering allows the customer to apply the coating technology simply and efficiently. SUMEBore™ is a holistic coating solution that—depending on the application area—gives the cylinder running surfaces of internal combustion engines specific properties.

Solid lubricants

Solid lubricants can be integrated into the coating by using powders based on iron and carbon. The coating, which is applied through thermal spraying, has the desired light porosity, while the engine oil in the spray pores reduces friction—in particular during a cold start. The coating is normally applied using the RotaPlasma™ spray process—a subprocess of the SumeBore coating soluton. In doing this, a rotating, bar-shaped, and water-cooled Sulzer Metco F210 plasma gun is inserted into the cylinder that is to be coated . Plasma guns using electrical arcs are used to heat a gas or gas mixture to more than 10000°C and to accelerate it. The added powder melts in flight, and the liquid particles create the desired coating when they impact the surface of the workpiece. Depending on

Coating a cast-aluminum motor block with a wear-resistant layer.

the bore diameter of the cylinder, a varying number of processing steps will have to be carried out in order to achieve the desired coating thickness of approximately 200μm. Because the roughness level is around 50μm, the coating will be honed in a subsequent working process. The definitive coating thickness that is finally achieved is around 120μm.

Temperatures of more than 10000°C

Because the plasma plume reaches temperatures of more than 10000°C and the geometrical conditions within a cylinder bore are tightly dimensioned, the workpiece will be subjected to high thermal stresses. Bores for adding compressed air are made on the rear side of the F210 burner; that way, the surfaces facing the plasma cool down directly following the coating. Compressed air is also used to focus the plasma plume optimally during the processing. An additional nozzle (shroud gas) is also located above the plasma nozzle, and serves to cool the components with cold gas (mainly argon) and shield them from the hot plasma flow . To ensure that the unmolten powder (overspray) causes as few flaws as possible in the coating, an additional axial airflow is forced through the cylinder bore and carries away any excess powder.

The goal of the simulation was to visualize the flow inside the cylinder and to investigate if the time and material efforts could be further reduced for the RotaPlasma spray process.

Numerical flow simulation

In order to continuously improve the process, the relationships of the complex

Plasmas during the coating process.

Simulation of the hot-nozzle and cold-gas flow. Cross section at the nozzle outlet, with visualization of the temperature (colors) and velocity (arrows).

max.

min.

[m/s]

Visualization of the flow during the coating process: 3D view of the stream lines from the nozzle.

process . Spraying trials carried out beforehand had indicated the influence of the compressed air pressure on the resulting quality of the coating. For this reason, the simulations were carried out with two widely differing pressures.

If the compressed air pressure is too high, the area of influence of the cold air moves forward along the circumference of the cylinder wall towards the coating zone and interacts directly with the plasma plume where it impacts the cylinder wall. This leads to a strong instability of the flow conditions during the coating and can affect the quality of the final coating. It can even lead to particles that were already molten in the plasma becoming solid once again before impacting the wall, thereby causing flaws in the coating.

Increased process expertise

The results achieved have led to an increase in process know-how and to an adaptation of the individual process parameters. Geometric optimizations to the F210 gun were not carried out. However, the knowledge that was gained will flow into the development of new products.

With increasing computational power and increasingly accurate models, numeric flow simulation has developed into a very important design tool in the last decade and has become virtually irreplaceable in the development process of Sulzer products.

Reto Wäger

Sulzer Markets and Technology Ltd

Sulzer Innotec

Sulzer-Allee 25

8404 Winterthur

Switzerland

Phone +41 52 262 42 50

reto.waeger@sulzer.com

How long has Sulzer Turbo Services been present in Houston and how many employees are now working for Sulzer Turbo Services there?

Sulzer Turbo Services has been present in Houston for 37 years. Started as Hickham Industries to service the local petrochemical industry, the company was acquired by Sulzer in 1985. Today, we have 450 employees in Houston serving the needs of customers in over 25 countries.

What is the attractiveness of Houston for Sulzer Turbo Services?

Houston serves as the repair hub for turbomachinery in the United States. With a highly skilled workforce, Houston offers Sulzer Turbo Services the ability to recruit and retain some of the best engineers and technicians in the business. The availability of reliable subcontractors in Houston is also very critical for Sulzer Turbo Services.

How many service centers do you have in North and South America and what are their capabilities?

Within North and South America, Sulzer Turbo Services has locations in Houston, New Orleans, Edmonton, Buenos Aires, Rio de Janeiro, Caracas, and Montevideo. Through these locations, we provide our