Industrial Pumps Blog

Packaged engineering systems have long been the Cinderella which has not gone to the ball when it comes to their popularity with engineering installations. Frequently, the common objection which is found is that a packaged solution will not be able to meet the client needs effectively, or that there will be issues in integrating the packaged solution into the system or indeed, that the total cost of ownership of the solution will exceed that of a one built in-house or from a tailor made alternative.

None of these objections is capable of standing up to close scrutiny when they are considered in individual situations.

Packaged solutions are capable of exceptionally flexible deployment, even into existing infrastructure and bring with them numerous benefits. They are capable of significantly reducing total cost of ownership through simplified installation procedures and with greater operating efficiencies due to integrated components and systems being used.

In addition, there are significant further benefits to be gained which are not always readily appreciated by clients.

Many clients find that they are burdened by managing a significant number of vendors in the procurement process. A packaged engineering solution removes a whole level of vendors from the equation; the burden then falls on the contractor engaged with delivering the packaged engineering solution instead of the client. This makes for increasing the effectiveness of your procurement process, and project management are also able to focus more effort and resources on managing the overall project without getting bogged down in the minutiae of the packaged solution. Using a packaged solution also means that communications between the client and vendors are streamlined down to a single point of contact, which increases efficiency and effectiveness.

Packaged engineering solutions do require an experienced partner to ensure the project deliverables are achieved. There is a need for extremely tight project management on the vendor side and liaising with the main, client project team. There is also a need for packaged engineering providers to fully understand the installation in the context of the overall project.

Pumping installations consume a large portion of the total power consumption of the entire operating system.  It is essential for commercial profitability that pumping systems operate efficiently and effectively. Inefficiencies incur a financial cost in terms of additional power consumption and increased total costs of ownership, in particular they are more expensive to operate due to higher maintenance costs, including both scheduled and unscheduled incidents.

The US Department of Energy has issued a three step process for assessing pumping installations on a standardized basis. In addition, the DOE report advises the use of a detailed assessment of pumping installations combined with a Pumping System Assessment Tool (PSAT) which highlights the cost/benefit aspects of the efficiency result and solutions.

#1 Identify the Major Elements and Equipment of the Pumping Installation

Larger items of equipment are usually the greatest consumers of power and the source of the largest opportunities for implementing solutions for energy and pumping efficiencies. Most pumping installations will find that they already qualify as a large-scale installation to begin with, so it makes sense to focus on the largest pumping elements first and work down from there.

#2 Identify Fixed Speed Pumps Used in a Variable Load Application Environment

Fixed speed pumps are not efficient across all load situations. This provides an opportunity for efficiencies to be found and the DOE notes the following situations which are of particular interest:

• Multiple parallel systems which are in continuous operation;
• Throttle valve control systems;
• Pump bypass lines or recirculation lines are normally held in the open position throughout operation;
• There is cavitation noise;
• Constant operation of the pumping system in a batch environment;
• Incidence of high maintenance captions, both scheduled and unscheduled; and
• Pumping systems which have undergone substantial alteration in their function or there has been a significant change in demand for their output.

#3 Check Pump System Performance Data & System is appropriately Matched to its Application

Design inefficiencies frequently result in mismatching of pumping installations to the operational requirement. Building safety margins into the initial design frequently results in inflation of the margin as the design proceeds through further iterations. This inflation of the safety margin is responsible for the frequent over capacity seen in many pumping installations, and it is not unusual to find a industrial pump installed which has double the actual capacity required for the system’s effective operation.

Crude oil transportation is a serious issue with oil fields located in remote locations, and as resources become harder to find, this will be an increasingly challenging factor in effective upstream operations. The distance and widely varied environments which require extensive design work for increasingly complex pipe networks. Monitoring and managing oil and gas pipeline networks requires sophisticated techniques and highly specialized expertise to ensure uptime and performance meet operational requirements and maintain company performance.

The single most important factor which has pushed to the fore of upstream operations and crude oil transportation issues is the consumption of energy.

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The European Union imposed a 0.1% limit on marine fuel sulfur, which came into effect on January 1, 2010. A survey by DNV Petroleum Services has revealed several critical areas of impact of the new regulations. The survey was conducted across 65 shipping companies who all responded to the survey by DNV.

40% of the respondents indicated that there was a lack of harmony across all of the EU states involved. This is surprising given that a fundamental building block of the EU is the harmonization of regulations across the trading bloc. Of particular concern were the variations in how different states were applying the emission standards and different methods of establishing compliance with the law. This has led to confusion within shipping companies, and a decrease in confidence in the regulatory powers by the industry generally.

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For clients, the total cost of ownership is the primary focus when making an acquisition decision.  This runs true no matter what the industry or application is involved, but whenever a decision is made the costs which should be included are not only the initial deployment or acquisition costs, but also the life cycle costs which provide a more accurate costing. Lifecycle costs include energy consumption costs, the opportunity cost associated with downtime, the cost of maintenance and spare parts.  Collating all these costs provides a Total Cost of Ownership or TCO.

The challenge is to source and implement an industrial pumps solution which minimize the TCO but achieve all the project deliverables.  Knowing what pumping principles are involved in a specific project (and therefore what type of pump is most appropriate) is essential, as is making a proper assessment of the dimensions involved.

Overall, the TO will be determined by numerous factors, some of which are under the control of the plant operator and some which are not.  Minimizing TCO involves:

• Pump optimization in respect of the liquid, especially taking into account viscosity;
• Optimization of pump system components;
• Understanding and addressing the deliverables of the pumping system;
• Optimization of the pump drive;
• Ensuring installation is optimal with minimal installation and downtime for other plant operating processes; and
• Ensuring dimensions are fully understood and are optimized.

All of these factors must be considered if TCO is to be minimized. However, it is not enough to understand each factor in isolation as they all interact to one degree or another – this means a holistic approach to the pumping process must be adopted, in order to gain the most accurate understanding of the project and the underlying cost issues.  Pumping components and solutions must be designed and implemented to work in relation to the surrounding infrastructure and also to handle the liquid or gas which is the subject of the pumping system.

Increasingly tighter regulations are being implemented worldwide to curb the use of sulfur-based fuels and the pollution which they create.  The European Union is one of the world’s leading trading blocs and also is leading the way in the use of legislation curtailing the use of “dirty fuels” on ocean going vessels.  The challenge for ship and fleet owners is that while they may have vessels which comply with regulations in say, the Far East, but which must now comply with the much tighter controls which exist in the European Union.

One example of marine pollution regulations which are causing serious engineering and fuel issues for ship owners are the European Union’s MARPOL (Marine Pollution) Annex VI Regulations for the Prevention of Air Pollution from Ships. These regulations prohibit the burning of sulfur-based fuel oils and provide for a strict timetable for implementation around various ports around the world. For instance, there are stated reductions in the emission of sulfur oxide (SOx) variants, carbon dioxide (CO2) and nitrogen oxide variants (NOx).

Additional EU Directives enabled in 2010 mandate that ships which are docked for more than 2 hours must use marine fuel oil which has a 0.1% or less sulfur content. For many operators, this means they must switch between fuel sources when they are in port to MGO – marine gas oil which is low sulfur but which is a poor lubricant because of its low viscosity.  In turn, the poor lubrication qualities will impact on the ships’ pumping systems and general machinery.

This contrasts with the situation prior to implementation of pollution emission regulations.  High-sulfur fuels could be used, which had good lubrication properties or lent it to being heated in order to improve pumping functionality.  Now low-sulfur fuels must be used which are already less viscous and would require excessive heat to be applied which is not feasible in an engine room (where the ambient temperature is typically around 40 degrees C and in some instances reaches 55 degrees C). The change in operating conditions needs cooling systems to reduce the oil temperature in order to thicken the oil so it can be pumped efficiently.

The Three Gorges Dam is one of the largest engineering projects ever undertaken in the world, and certainly it is the largest dam ever.  It is not simply sheer size which makes the Three Gorges Dam special; it has a total electricity generation capacity of 22,400 Mega Watts (MW) which requires a 24/7 x 365 oil pumping system to govern the hydropower unit. Such a huge system requiring continuous operation presents a number of unique and highly challenging engineering problems.

The original industrial pump which was installed failed to operate successfully requiring them to be replaced.  Before replacements could be sourced, a detailed analysis of the pump system which had broken down had to be undertaken, including returning to the original design parameters for the electricity generating system, to understand the challenges and reasons for failure.  There was also the design challenge of having to come up with a work around solution in order to implement a modified installation to the existing infrastructure.

Only after a detailed analysis was conducted could a new engineering solution be implemented.  The new pumping system now incorporates fail safe technology together with properly loaded pumps to handle the capacity which is generated.  The replacement solution is now in situ and operating successfully.

For an energy hungry such as China, the Three Gorges Dam is only part of a series of power generation infrastructure projects which are being developed to supply energy to one of the world’s fastest growing, manufacturing based economies.  Despite the size and scale of the Three Gorges project and other energy generation projects, there is still the need to curb electricity usage in major Chinese cities today – a sign that further projects and more efficient power usage will need to be developed further.

A company manufacturing isopropyl alcohol was finding itself having to tackle heavy condensation creating operating issues. The major contributing factor was a plant modification which was creating excess thrust load on a steam turbine, and this, together with a steam-extracting condenser with a leaking labyrinth seal was responsible for degradation in capacity.

The result of these two defects was that more steam was applied to the low-pressure side of the labyrinth seal, resulting in excessive condensation.  The condensed water was then working its way to a lubrication system where it accumulated.  The water accumulation then had to be manually drained from the lubrication tank every 8 hours (around 5 quarts had to be removed on each occasion).

This was not the end of the problem: the lubrication oil also contained excessive water levels which resulted in high levels of corrosion, particularly on the thrust collar mounting around the turbine shaft.  The weakened shaft also had to deal with the excessive load, resulting in several occasions of the shaft failing over a number of years.  On each failure, the plant had to be shut down resulting in a week’s loss of production and non-scheduled maintenance – the cost of each incident was in the region of $100,000.

The Solution

Analysis of the lubricating oil was undertaken together with the size of the reservoir and water content. An oil purifier was sourced and fitted to remove water from the lubricating oil, including emulsified and dissolved water within the oil.  This allowed the lubricating systems for the compressor, turbine and hydraulic systems working at their proper levels of efficiency, reducing contaminating water from 1,000 parts per million (ppm) to less than 100 ppm.

While this was the practical solution which was implemented, and it seems obvious, the solution was only arrived at after extensive discussions and consultations with the plant management and technical team.  Once their operating and technical needs had been fully assessed, then and only then could an engineering solution be sourced and implemented.

The vacuum pump was invented over 350 years ago by German scientist, Otto von Guericke.  The vacuum pump’s first application was in scientific experiments which required the removal of gas molecules to create a vacuum or a partial vacuum. The humble vacuum pump has modern applications, but there are now several variants which use the fundamental operating principal.

Broadly, there are three types of vacuum pump:

• Positive displacement pumps;
• Entrapment pumps; and
• Momentum transfer pumps.

Positive displacement pumps continuously create a vacuum by manipulation of a diaphragm or rotary action. Positive displacement pumps are by far the most common variant of vacuum pumps in operation today. The primary application of positive displacement pumps are in fluid transfers because they actively move the fluid (hence positive displacement and because a fluid cannot be “pulled”).

The entrapment pump works by using temperature.  Cold temperatures are used to create condensation from gases and convert them into a solid state. Molecules of gas are trapped in a confined space (hence entrapment) which is known as a “cold trap”.  Here the gas molecules are turned into condensation or a liquefied state, while ionized gas is used to power an ion pump.

Momentum transfer pumps, also known as molecular pumps, work by means of a high speed jet of fluid, or alternatively, a very high speed rotor.  In either case, molecules are “knocked out” of the pump chamber and the gas molecules are transferred to the exhaust stage of the pump. There are two main types of momentum transfer pump – diffusion pumps and turbo-molecular pumps.  The diffusion model uses a jet of dense fluid such as mercury to create molecular displacement, while the turbo-molecular pump uses the high-speed rotor method. Typically, both these types of pumps work at very low pressures, i.e. 1kPa, and in both cases the pumps will fail if the gases are vented directly into the atmosphere or exhaust environment of similar pressure, then the pumps will fail, so it is necessary that they vent into low-pressure vacuum which will require the use of another mechanical pump.

Centrifugal pumps utilize a rotating impeller which serves to increase the pressure and flow rate of the fluid.  Centrifugal pumps are most commonly used to transfer liquids around piping systems.

Centrifugal pumps operate by the pressure differential created by the impeller.  The impeller’s rotation within the pump casing takes energy provided by the motor and accelerates the fluid away from the center of rotation.  This outward movement creates pressure due to being confined within the pump casing, and this in turn causes liquid flow.

The fluid being transported enters the pump along the axis of the mechanism, and may pass through a diffusing chamber after passing through the impeller mechanism.  The diffusing chamber may also be referred to as a volute chamber, and from here the fluid will enter the discharge outlet.  It is usual to find a centrifugal pump being used to high pressure discharge of fluids through small discharge heads.

A variant on the centrifugal pump is the screw centrifugal pump. This was developed in the 1960’s to handle delicate items which need to be transferred in bulk but at the same time must be handled without damage.  The first application was for transferring fish catches from trawlers nets into the holds of the boats, and again from the trawlers to dockside for processing.

The screw centrifugal pump is now commonly used to transport foodstuffs, crystal products, oily water and sewage.  The screw centrifugal pump is also capable of handling extremely long fibrous materials such as rope without jamming the pumping mechanism.  This makes this version of the centrifugal pump a favorite amongst municipal authorities who need sewage and waste removed and processed. The screw centrifugal pump also provides excellent flow control within its operating range, and again this makes it an excellent choice for handling delicate items.