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Phil Norris

Last August in our article entitled “Review of Process Pipeline Valves (1)“, I promised you that we would go a little deeper into the types of valve available including different ways to actuate them for specialised applications.  You will remenber that I did a quick canter through the main types of process valve available by comparing them to examples in our household heating and plumbing.  These included ball valves, gate valves, globe valves and reflux valves, all of which have quite diferent characteristics.

This time, I will be looking much more at how these are used in the Process Industries and the absolutely astonishing range that is available for the huge number of applications to control pipeline liquid, gas, granular solids and slurry flows from cryogenic applications like liquid Nitrogen and Helium to high pressure and temperatures that can be found in liquid and gas flows such as can be found in the petrochemical and chemical industries where flow need to be controlled with precision and speed of response.

Taking the humble gate valve in it’s simplest form found as domestic water stopcocks.   This type of valve comprises a planar wedge shaped ‘gate’ that is pushed into a matching wedged shaped circular slot.  The big advantage of this kind of pipeline valve is it’s relatively slim profile and the fact that it does not restrict the flow when fully open since the valve body aperture is normally oversize in relation to the pipeline.   On the other hand it is not normally used for control the flow since nearly all the change occurs near closure.  Problems with the gate valve are wear to the wedge mating surfaces, sticking through corrosion, leakage through the gland in the valve pressure seal bonnet and vibration if used for throttling the flow.  Sizes are usually in the  range 15mm (1/2″) to 80mm (3″) and up to 60 bar pressures.

A Typical Parallel Slide Valve

A more specialised version of the gate valve for low pressure applications such as slurry control to and from tanks, is the uni-direction flow knife gate valve.  This features  a circular “knife” wedge that has a non-clog seating design particularly useful for liquids with a high solids content.  These are generally available in sizes up to 1200mm(48″) diameter.

A further variation is the Parallel Slide valve where the wedge shaped knife is machined with parallel faces.   Again, this is used for unidirectional pipeline flows of fine granular materials including grain, sand, salt and other chemicals.    These are available in a large range of sizes up to 15oomm (60″) and are in appearance, very similar to knife gate valves.

Another similar looking valve is the Butterfly Valve that has a quite different principle of operation.  These are akin to the simple ball valve or trunnion valve collectively known as Quarter-turn Valves.  These type of valves have the controlling vane that is constantly within the flow.  The trunnion or control shaft needs only a quarter-turn to be fully open or fully closed.  Furthermore, the forces needed to open or fully close them is relatively small as the pressure distribution remains the same both sides  of the trunnion shaft wherever the vane is positioned.   These types of valve are again low profile within the pipeline.  They are typically used for higher pressure clean water applications with sizes up to 600mm (48″).  Since these valves can achieve quick shut off, avoiding water hammer is vital.  The enormous forces in say reservoir pipelines have to be seen to believed.  I have seen a such a buried pipeline no longer buried and broken after an operator carelessly shut a butterfly valve quickly.  OOPS!!

As you can see, we have still just scratched the surface of this vast subject.

Hasta Manãna

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Main Blog Site Editor

Hello again supporters, industry colleagues and friends.  The reason that you haven’t heard from me for a little while, I have, in my advancing years, been supporting a really worthwhile community power group in my village called Tutbury EcoPower.   I have been banging on about saving energy in my articles in the Processing Industry and this is no accident as I believe that it is also good business.

Likewise, with community-based projects, it is essential to get such projects onto a sound financial footing and be organised, even though all the team are volunteers.  I have the honour to be an integral part of one of the most well-organised community groups in the UK who really do have a good range of professional skills in the team.  We are all volunteers and we believe passionately in changing attitudes with respect to a sustainable future both financially and in energy terms in the local community and now further afield.

Ye Olde Dog & Partridge hostelry

In the summer of this year, Tutbury EcoPower, as one of nearly 1,000 other community groups entered the EngergyShare (a consortium of British Gas, River Cottage and the eco-group EnergyShare) competition to win a big cash prize to be spent on sustainable energy projects.  After 2 phases of voting, Tutbury EcoPower is now one of 6 finalists to win £75,000 in the medium-sized project section.

Tutbury EcoPower has committed to installing Solar PV Panels on community buildings such as the village hall which is used for all sorts of adult education, keep fit, children’s groups, wedding receptions and many other events, the old school house which is in full use by the scouts, mother and toddler group and youth club.  With such installations, the venue custodians get cheap energy and Tutbury Eco Power gets the Feed-in-Tariff to re-invest in other such projects and thereby grow over time rather than relying on scarce handouts.

Tutbury EcoPower’s flagship project of a 75kW archimedean screw generator on the River Dove, when operational will generate some £30,000 per annum to re-invest in other community projects in a sustainable way.

As this group is a great exemplar for good community and business practice that relies on profit/surplus to keep it going, I am now making an appeal for you all to vote online for for this most worthwhile of projects.  If you want to know more and see how we are progressing see us on Facebook.

I can recommend getting involved in this way just as I have.  I still have my day job but it really gives one a real fillip.  If you are a professional person, you would want to see it succeed not only because you are made that way, but the community knows where you live – No pressure then!

Hasta mañana

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Phil Norris

Hi there after a long absence.  This time we shall be having a good look at how the process industry can become more sustainable in energy terms both now and in the future through the appliance of good science.  This is prompted by a debate last week at the Scottish government’s Low Carbon Investment conference in that the development of offshore wind energy on offshore wind energy.  The fear is that a poor regulation and a lack of skills in industry will lumber Scotland with an unsustainable offshore wind energy generation industry.

On the one hand, a government’s view is that the pace of development is unsustainable to achieve Scotland’s new target of 80% (as opposed to a 50% previously) coming from renewables by 2020.  This should be set in the context of a Europe-wide target of 20%.  The contra view expressed by an investment banking group was: “unforgiving” targets were necessary to foster ambition and leadership.  Another view from the renewable power industry was a warning that focusing on a medium term target for 2020 will lead to a boom and bust scenario with the industry going over a precipice after 2020 when the target has presumably been achieved.

What has this got to do with the process industry?   Well, the process industry is a big user of energy and some parts of it at least are investing heavily in using new technologies and science to wring the best efficiency out of the various processes to reduce energy costs.  It is good business after all, especially with the price of highly taxed energy, to reduce the processing costs.

The Scottish debate serves to demonstrate that, in keeping with the rest of the economy, the sustainability of increasing the rate of change in the UK and the wider world towards a greater percentage of installed power generation, is partially reliant on private investment.

My own view, which come from a long career in project management, is that one, you need to set a goal that will provide the result in the future needed for the good of the planet and the life upon it and two, you should set about finding a viable (sustainable) means of achieving it.  The debate at the planning stage, comes about because there is a perception of over regulation.

Private industry, principally the process industry, generates huge incomes from generating power and it is being invested in new science and new technologies.  The problem is the sheer amount of energy that civilisation uses to sustain and grow itself.   Mankind is rapidly approaching a watershed where fossil fuel use becomes unsustainable (perhaps we have even gone past it).

New Renewable Energy Source

But when will the next commercially exploitable  scientific breakthrough come about?   People like to think that Nuclear Fusion is the answer but its commercial exploitation is seemingly still decades away.  No, we are faced with the now of using renewable energy from the wind, water, the sun and heat from the ground.  Therefore we should be looking to throw a lot more energy (perspiration) in achieving sustainable economic growth and ever greater efficiency in our energy use and reuse and not worry too much about undue regulation to get there.

The Scottish debate and historical precidents in the industrial revolution only goes to show that wanting to maintain an industry beyond its natural lifespan never has worked and is unlikely to do so in the longer term.  In 2020, we will no doubt be looking back and saying we have bought some time in ecological (climate change) terms  and in the future, new technologies based on novel science will at last be in view and be taking over.  The process and power industries will still be there, using their economic muscles, to take sustainable power and power usage forward.

My last word on this, perhaps, controversial subject this time, is that the process industry should continue to lobby for less regulation and more action to ensure that we don’t miss the chance of achieving sustainability in our energy use, not only for for the energy itself, but also for less regulation to ensure a flexible but sustainable power industry.

Hasta mañana

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This time, I would like to talk some more about energy efficiency and heat recovery using the latest liquid heat exchangers and vapour condensers.  As you might already know if you are a regular visitor to this blog, I have a green streak running right through me in engineering and process terms.   Why apply heat using fossil fuels when you can have it for free from the sun from on high, the air all around us and in the ground beneath us?

I recognise that the process and manufacturing industries cannot just rely on ‘free’ energy but it is clear that they are moving towards ever greater efficiency by energy recycling with the use of heat exchanger equipment such as plate vapour condensers and evaporators, liquid plate heat exchangers.

So how do plate heat exchangers work?  In essence, it is passing two fluids over a common plate or pipe wall but on opposite sides.  The hotter liquid flow is cooled and the cooler one is warmed.   You can immediately see that the heat transfer for given flows is dependent on the conductivity of the plate or pipe wall, the temperature differential between flows, the contact time on the heat transfer surfaces and the mass density of both fluids.

The only ways to increase the efficiency of heat transfer for two given fluids, is to increase the contact area, increase contact time, to reduce the thickness of the transfer plate/pipe wall and to use the most thermally efficient material for the  transfer surface.   By far the most significant factor is the area of contact surface area followed by the contact time.

The traditional shell and tube heat exchangers, such as can still be found on on steam locomotives, are designed to produce steam under pressure and the spent steam (after driving the loco and operating the brakes) is used to heat the feed water in the loco’s tank.  There are limitations to the contact area possible this form of  vapour condenser, especially as one fluid is a gas with it’s low thermal conductivity and the other is a liquid.  Such heat recovery is not particularly efficient in such equipment.  Nonetheless, the shell and tube heat exchanger has its uses of large power plant where space is not at a premium and the fluid pressures are high.

1st Heat Exchanger invented by Gustav Laval

Gustav Laval is credited with the first plate heat exchanger in 1890 to cool milk and, in essence, the principles have not changed, only the variety of applications the humble plate heat exchanger is now put to and innovative design solutions.  By using a stack of welded (or brazed) profiled pressed steel or alloy plate cassettes connected by gaskets to form a series of connected alternate chambers with two entirely separated flows in close proximity, a much more efficient solution is possible.    What is more, of course, the thin and convoluted spaces ensure that the contact time is maximised and the thin pressed metal plates ensure that the maximum heat transfer occurs.  Thus heat exchanger equipment has a tiny footprint compared to other heat exchange methods.

The now ubiquitous plate heat exchanger can be found in food and beverage production, pharmaceutical and chemical industries as well as forming the backbone of many industrial and commercial heating systems.

Alfavap Plate Evaporator

One of the more recent innovations, is the vapour condenser and the similar evaporator that uses two fluid phases, gas and liquid.  The principles are exactly the same as the liquid-to-liquid exchangers and it is only the relative flow rates, enclosed space capacities and the flow paths that have been optimised for the two-phase exchangers.  The Afavap from Alfa Laval has been especially developed for evaporation and crystallisation processes.

These exchangers are available in exotic materials such as SMO, titanium, nickel and Hastelloy™ to ensure no chemical interaction occurs during the heat exchange process.  The illustration gives a good illustration on how these particular plate heat exchangers work.

Flexibility is the watchword for plate heat exchangers in that if the process needs adjusting, cassettes can be added or removed, gas pressures can  amendeded and they can easily be cleaned by clean-in-place (CIP) systems.

Heat recovery to reduce our reliance on fossil fuels is therefore being optimised by use of plate heat exchangers and vapour condensers.  We will, no doubt, be returning to this subject in future posts.

Arrividerci

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Main Blog Site Editor

If you live near a large sewage treatment plant as some of us have done sometime in their lives, you will, no doubt, be aware of the characteristic smell of sewage sludge being processed in big enclosed tanks with a gas holder on top that stand prominently above the rest of the plant.  What you may not have realised is that one of the important by-products of this treatment process is the bio-gas methane.  The resulting sludge is then de-watered and used as soil conditioner that is a it is a bit like peat that doesn’t smell much at all.

For 40 years or so,  anaerobic digestion in large enclosed reactors has been producing the bio-gas methane in sufficient quantities on medium and large sewage treatment plants to both provide the heating source for the anaerobic process and a modest surplus at times to supplement district heating schemes or to run on-site generators.

So what is anaerobic digestion?  Simply put, it is the processes that use micro-organisms in the absence of air to break down putrescible organic matter into bio-gas, carbon dioxide, solid and liquid residues that can be used on the land as a safe soil conditioner/fertiliser.

Producing bio-fuel as a substitute for fossil fuels is not new.  Indeed, it is quite possible, with a few engine modifications, to use vegetable oils as a partial replacement for diesel fuel.  However, this process is not as ecologically friendly as  producing bio-gas in view of diverting large acreages of of arable land for growing fuel instead of food.   Bio-gas production uses waste products like manure, domestic sewage, silage.

There are two general types of anaerobic digestion, mesophilic and thermophilic; the former operates between 25ºC and 40ºC and the latter between 55ºC and 60ºC or even higher.    The microbes that are used differ in each case but the outputs are similar in composition but the quantities are greater with thermophilic digestion.   Earlier sewage treatment plant digestors used the lower temperature mesophilic process only for economic reasons and for the fact that they were designed to render a large quantity of problem material into a small amount of safe and “sweet” smelling one.  The bio-gas was a handy by-product.

With the perceived need to produce bio-gas as the main product, the economic model altered in favour of maximum bio-gas produced for the minimum solids input to the process.  Therefore, some modern plants use both processes in series to ensure that all the cellulose and other hard-to-breakdown organic material such as wheat stalks and woody bits are broken down to produce the optimum useful bio-gas.

This type of processing is usually very expensive to construct and therefore it is very important to insulate the vessels to retain the correct temperature as well as  ensuring the ‘health’ of the microbe populations.   Therefore, controlling the process using Bio-Gas Process Analysers has become very sophisticated.

The gaseous outputs from a biogas plant include Methane (CH4), Carbon Dioxide (CO2), Nitrogen (N2) a small amount of Hydrogen (H2),  and a trace of  Hydrogen Sulphide(H2S).  This latter gas is highly toxic, corrosive and it has a very strong odour in trace quantities.   It is this gas, above all others that gives sewage plant it’s characteristic odour.  Thermophilic digestion is less likely to produce this gas than the mesophilic process.

The bio-gas analyser uses 5 gas sensors to measure each of the above-mentioned gases.  In the above diagram, the gas sample from the digestor comes in from the right hand side.  There is a flame (Deflagration) arrestor followed by a water content sensor.  The five sensors then detect the five gases.  Before these sample gases can be released, they need to be filtered for H2S before exhausting into the atmosphere and to protect the sensitive pressure sensors.  The outputs are digitised and the signals are conditioned and amplified so as to be compatible for integration into fieldbus control systems or for monitoring locally via Ethernet connections on a PC.

To measure these gas flows, a thermal flow switch or  mass flow transmitter is used.  By measuring and monitoring the relative quantities of each gas used, the health of the various process stages can be determined.  These gases being of distinctly differing molecular weights, are drawn off at different points of the digestion process.  In all cases,  H2S needs to be filtered out to avoid contamination of the product gases.

The thermal mass flow transmitter uses the principle of varying flows cause different cooling of a heated probe.  Again, these transmitters are designed to be incorporated into  the common fieldbus process control system.

You can see that anaerobic digestion has come a long way since the rather crude sewage digestors used in the last century.  The economic and ecologic reasons for producing bio-fuel from waste or by-products of agriculture are, however, relatively new.  It will be difficult to see how extensive bio-fuel processes will become in the twenty-first century as burning anything produces the greenhouse gas CO2.  We will watch this debate with interest.

Hasta mañana

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Looking into my heating cupboard at home, I see at least four types of valves in use.  The one on the top of my pressurised hot water tank controls the cold water feed from the mains, is a 15mm diameter ball valve with a handy quarter-turn lever.  This is a quick shut-off valve that controls the whole hot water supply.  I also see lots of  in-line ball valves under each basin with screwdriver actuation that act as isolators for each tap – very handy when you are changing tap washers.  The actuated 3-port diverter valve on the boiler outflow pipe is another form of ball valve.

I also see a brass gate valve  on the mains water inlet that tends to stick when you least want it to.  On the radiators I see lock shield valves on each radiator outlet that can be used for fine control.  These are a form of globe valve.  Some of the taps (faucets) on the sink are a form of globe valve which are great for accurate control.   Finally, I see reflux valves on the pump delivery side to stop reverse gravity flow damaging the pump.

I am sure that you are not really interested in my house plumbing per se because they are so familiar to you, but I mention them because the valves represent all the basic types of valve used in the process industry and the wider utility and industrial sectors.  The size, connections, how it is actuated and materials it is constructed from all vary tremendously, but the principle is the same for each ball valve, gate valve, globe valve and reflux (or non-return) valve.

Let us first look at the ubiquitous ball valve.  When I looked at various valve catalogues, I was amazed at the variation of types, standards, duties and constructions.     The straightforward ball valve has a close-fitting stainless steel ball larger than the pipe diameter set with a very short spindle on the top only, that has been bored out such that it is slightly smaller than the pipe diameter.  Actuation can be manual, direct quarter turn or geared) or by geared servo actuation.   Sizes vary from 8 mm to 500 mm diameter and for most pressure duties between 10 and 40bar (150lb to 600lb).

Typical 15 mm dia. ball valve

The variations on this basic type include flow control ball valves where instead of a bored hole, there is a triangular shaped hole with one point perpendicular to the spindle axis.  As the hole opens, only a small area is presented at first and this is progressively increased as the spindle turns through 90 degrees.  For larger sizes and higher pressure duties the humble ball valve turns into a trunnion valve with a spindle (trunnion) right through the ball (and hole) and with two bearings, top and bottom.

For pipelines where pigging is carried out, the hole through the ball is oversize so that the cleaning pig can pass straight through (when the valve is open of course).  Yet another variation is the diverter valve where there are three pipe port fittings and the ball is drilled with a “T” shaped hole.  These valves are for In position one it is closed with the “bar of the “T” against the inlet port; in position 2 at 90 degrees left , flow is diverted to one of the outlet ports and at 90 degrees right, flow is diverted to the other port.  Yet an other form of this type of valve is the butterfly valve where instead of a ball, there is a flat disc that is trunnion mounted.

Next, we go to the globe valve which comes in a variety of forms and sizes from 15 mm to 600 mm and with duties from 10 bar to 100bar.  The valves all feature a two-chamber casting separated by a web that has been drilled and seated to allow a screw actuated spindle mounted plunger to seal this hole.  These unidirectional valves are usually specified for pure liquids and gasses where no leak shut off and fine modulation of flow is required.

The next category is the gate valve type.  These valves are usually available from 15mm to up to 1,000 mm diameter.  They act as a rising and lowering shutter perpendicular to the flow.  These bi-directional valves usually feature a narrow wedge shape that assists in positive seating.  These valves are generally used for clean water or liquid applications.   Conversely, the knife wafer valves in the larger sizes are used to control slurry tank or reservoir outlets or inlets in mining and power station applications.  Seating design is modified to allow self-cleaning sealing surfaces.

Finally we touch on Non-return Valves ( NRV  or reflux valves).  These are used for ensuring that pipe flow remains unidirectional and therefore they are mostly found on pump delivery mains to protect the pump from back flow.   These come in many sizes and types including the lift check valve, swing check valve and spring loaded types.  For high pressure duties above say 2″ (50mm) size, it is usually essential to have these valves anti-slam to avoid the damaging effects of water hammer (hydraulic shock) when the pump stops.

We will be returning to this subject in more detail next time – so keep visiting.

Hasta mañana

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Main Blog Site Editor

In this article, I am having a look at two testing tools that are coming into use on processing plant that require no dismantling of the process equipment.  Diagnostics to the process or the plant equipment need to be performed whilst the plant is in operation and taking it off-line to carry out checks is a definite no-no unless absolutely necessary.

First up is infrared imaging to take the temperature of various parts of the process.   We’ve all seen the typical documentary TV programme where the police helicopter locates miscreants hiding in the undergrowth using their on-board thermal video equipment.  Their body heat shows up black against the greys and whites of the thermal images on the screen in real time.  Big brother is watching you it seems.

Fluke-ti29 thermal imager

For industrial and other sector usage, thermal imaging these days is very precise and modern imagers such as those produced by Fluke UK Ltd can be calibrated to measuring temperatures up to  ≤ 0.05 °C .  At this sort of accuracy, you can see fresh footprints on concrete.    Their new Ti29Thermal Imager takes digital ir images from the sensor as well as a visible light coordinating image to show exactly the point of measurement from the same viewpoint.  You can even use additional telephoto lenses for measuring temperatures in hard-to-reach places from the safety of the ground – brilliant and what a time saver!

You can see that such an thermal imager with it’s  great accuracy is very useful to monitor process vessels, motors, gearboxes using before and after maintenance or repair.  What is more, the rugged nature of this equipment means that it can be be thrown into the the back of the site engineer’s van without worry.

Thermal images are now in glorious colour palettes as well as greyscale.  The one that I saw was procured for our community project where we were demonstrating heat loss from properties.  Bright red as the worst heat loss is quite good at persuading otherwise skeptical home owners to do something (and save money of course).

Fluke 810 vibration meter in action

Next up is the hand-held vibration tester which also is a very handy tool in the armoury of the roving site technician.   Monitoring sound and vibration is an early warning indication that there is a problem with mechanical equipment such as pumps, motors, gearboxes and transmission trains.  We can all remember putting our ear to the back of our fist whilst holding a screwdriver to the recalcitrant car engine to try and hear and feel what might be wrong.    Like a medical stethoscope user, the screwdriver test requires training and experience and even then the testing method has severe limitations.

Modern vibration testers (or vibro meter) like the new Fluke 810 vibration tester use a compact tri-axial accelerometer.   This is attached to the machine being diagnosed using a magnetic clamp and the cable connecting it to the ruggedised analyser.   This particular vibro meter monitors vibration in the range 2 Hz to 20 kHz and can provide a digital read out that is analysed into its various components.  What is more, it provides a revolutionary instant analysis in the handheld device for accurate troubleshooting.

The modern maintenance engineer needs all the easy-to-use technology at his fingertips to ensure the least downtime by targeted maintenance and replacement that can be predicted with confidence.   The modern financial environment demands ever more efficiency and the modern handheld devices can protect the plant process from unplanned interuptions with intelligent maintenance regimes.  This is a particular hobby horse of mine and I will be returning to this subject another time – so keep visiting.

Au revoir until the next time.

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Is your processing plant safe?  Can you be sure that if a cataclysmic event occurs, will your plant a) survive? b) if not, will the surrounding environment suffer? or c) will you be able to resume production after repairs taking a few weeks?  The answer may be how long is a piece of string or it could be that initial design and production assumptions have changed and it is now time to carry out a ‘pressure test’.

You may have seen in the paper today, the news that the Japanese nuclear operators going to ‘pressure test’ all 54 of their nuclear generation plant as a direct result of the Fukushima Daiichi plant disaster in which they were subjected to an unprecedented earthquake measuring 9.0 on the richter scale followed minutes later by a huge tsunami from the sea.

Apparently, these stress tests are to evaluate the ‘resilience’ of  each of the plant to continue to operate safely or at worst, shut down safely and contain any fissionable material within its reactor vessels.  For most who do not have a passing knowledge of nuclear plant or plant in general, it is hard to imagine what this test could be.  Is it a test to destruction? – No, that’s plainly not sensible as currently, Japan is still reeling from the consequences of the disaster with only 19 of their 54 nuclear generators in service and of course, further failures cannot be contemplated.

The real answer is that Stress testing is political and media short-hand for risk assessment that is to be carried out over a period of months for each plant.  I don’t know about you, but risk assessment doesn’t have the sense of immediacy or importance that the term stress testing has. It’s a bit like the clamour for a public inquiry in the UK in the wake of a disaster – somebody has to do something!

The problem is that unprecedented cataclysmic  events are, by its very definition, not predictable.  If plant designs had to take account of worst case scenarios, then nothing would ever get built in the nuclear line.  I have absolutely no inside information except to say that risk assessments are part of the routine processes of creating and thereafter maintaining any plant, nuclear, petrochemical or any other.

600-Station Geodetic Array in Japan

The stress test in this case has to mean reassessing both internal operating factors and external environmental factors have changed and applying it to the plant design.   Japan is in the most active earthquake area in the World with three major fault lines passing close by most of their nuclear plants.  It is no surprise that geodetic arrays with over 600 monitoring sites was set up in 1996 by the Geological Institute (GSI) of Japan to develop not only an earthquake prediction model, but also to assess their earthquake building codes.

The fact is that Japan did make what they thought were the correct design assumptions based on this developing body of monitoring data but even their 10 metre-high tsunami wall at  Fukushima Daiichi was easily over-topped.  So a review with a new risk assessment (pressure test) is required that focuses more, perhaps on the environmental and loss-of-life potential.

No doubt, there will be no more news for quite a while except for rumblings in the Japanese Diet (Parliament) and by international environmentalists who want to shut the global nuclear industry.  The only headlines along with an enormous amount of flack in the media, will come if any of the much-needed 54 nuclear generators in Japan are forced to close permanently due to its pressure test. Cries of deceit and corruption will no doubt be in the wake of the furore.

I hope your processing plant is safe from all that the Planet can hurl at it as can be ‘reasonably’ predicted and that the consequences are minimised.  Let’s hope your risk assessment processes are up-to-date, observed and reasonably free from political or financial influences.

Hasta mañana

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Phil Norris

I said that I would get back to you on what has caught my eye on the process industry equipment front, so this time, I am having a look down-the-hole (or downhole as some know it).   This is an environment that has been described as the most violent and extreme on the Planet and this is an area that attracts a lot of media and governmental attention when things go wrong.

In my last editorial, I talked about one such instance of media attention, extracting petroleum gas from shale rock and the now infamous ‘fracking’ process.  What caught my eye was how extensively this process is used in exploration and exploitation of the Earth’s natural resources.

As a non-petrochem industry person, I know very little about the processes but after a little investigation, I now know that ‘fracking’ is used not only for gas extraction, but also for both creating underground reservoirs for water storage far underground  and, conversely, extracting fossil water.  If you search on Wikipedia for fracking, you can see what I mean.

As a serious Engineer, I have been amazed at some of the equipment that has been developed for use 3 miles down- the- hole where pressures can reach 1,700 bar (25,000psi) and 240°C.  Like Maxon Motor’s new EC 22 HD brushless DC motor that is used to control the drilling head.  Bathed in hot oil, having to withstand vibration of up to 25 grms and impact forces of up to 100G, these little motors, developing 240 watts, have to keep going for thousands of hours without attention – extreme or what!

Some of the downhole submersible pumps as found in deep water extraction applications,  have to be almost as tough.   Water utility companies use 4″ to 12″ diameter multi-stage centrifugal submersible pumps that have to be at once, constructed out of hygienic materials, have the highest electrical enclosure standards (IP67), operate in high pressure environments (up to 1,000 metre hydraulic pressure) and, of course, be robust and well designed to operate for years with little attention.

I marvel at the diagrams in the media and in technical papers that show how far from the vertical boreholes go thousands of feet down and miles away from the well head.  I got to wondering how they manage to get the drill head to precisely where the oil-bearing stratum is.    The easy to understand bit (sic) is establishing where the target area in Cartesian coordinates is; via seismic survey methods of course.

The more difficult part is to navigate the drilling head to that target area.  This has to be done by ‘dead’ reckoning day-to-day with perhaps an occasional seismic survey (carried out at great expense) to check where the drill is in relation to the target area.

The down-the-hole guidance controls at the drilling head include highly sophisticated accelerometers and tilt sensors (inclinometers) as part of the guidance equipment and these have to be tough to resist the extreme environment at the drill head.  Modern electronics make red reckoning an exact science.

Dead reckoning come a long way from when mariners of old used to measure the ship’s speed by throwing a log tied to a rope overboard and measured the number of knots on the rope that went through the matelot’s hands in a minute, the navigator calculated the course with the compass heading and average speed in knots and everybody hoped they all got within 26 miles of the target port.

Visit us again – Hasta la vista

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The UK’s Shale Gas is in the news on the occasion of a  recent report by the Energy Select Committee of MPs which has found no evidence that the hydraulic fracturing process involved in shale-gas extraction will affect underground water aquifers as long as the work is done correctly. The report goes on to say that onshore reserves are not likely to bring down the price of domestic gas.

This process, known as ‘fracking,’ is entering the general public’s vocabulary along with a rather dramatic (some say hysterical) debate about the dangers to the environment with alarming videos on U Tube from the US of escaping gas getting into the water supply and being ignited in domestic sinks.   This has led to calls for a moratorium gas extraction in this way by environmentalists and in a newly released report from Manchester University has said that the environmental impact of shale gas is lower than coal, but a much higher impact than nuclear, solar or wind power.

Cuadrilla Resources, the company that is bringing this technique to the UK, has said that their process of fracking is well tried and in any event is not the same as the technique that has been the cause of so much trouble in the US.  Consequently the process  is very much safer to the environment and therefore, no ban is necessary.  The energy select committee seems to agree with them.

To give you some of the background, the British Geological Survey has estimated that the UK’s onshore shale-gas resources in the UK , mainly in the North West, amounts to some 150 billion cubic metres.  This equates to about 1.5 years of total gas consumption in the UK and worth some £30bn at current prices.

The chairman of the Select Committee, Tim Yeo MP, has observed that the onshore reserves are only the tip of the iceberg and that offshore reserves could make the UK self-sufficient in gas at sometime in the future if exploited and this is very much supported by the Select Committee.

Given that shale gas extraction using a fracking process is widespread in the US with the Report estimating between 15% and 80% of the chemicals injected into the ground used getting to the surface as flowback along with potentially, leached out heavy metals and radioactive minerals getting into the water supply, is the new process going to be safe?  Cuadrilla Resources are going to extraordinary lengths to seal the site in Lancashire from the Sherwood aquifer below to ensure that the flowback does not leach into the supply.

I have listened to the debate both informed and uninformed on the radio and I have to say that the cynical view from the listeners that it will all go wrong just as in the US, has gained the ascendency.  Certainly, this is a “get out of jail” card for the UK energy industry and could take the primary focus off exploiting renewable and environmentally friendly energy sources to reverse global warming.

In my view, the reality is that this is a side show and low impact alternative energy, that does not rely on burning fossil fuels,   must be pursued with all vigour and this is where the UK government should maintain their focus.  The petrochemical industry will no doubt rise to the challenge of safely delivering shale gas using private funding.