Waterjetting 1d - Not quite that simple!

When I first began the research on the applications of high-pressure water that was be one of the major parts of my professional life I must confess to a certain naïve innocence in regard to other folk’s work. One assumed that other folk had made similar mistakes to mine, and then corrected them, so that when different systems were compared that the early, obvious, mistakes had not been made.

One of the first times I found that this wasn’t the case was when we were asked to go and demonstrate that high-pressure waterjets could economically cut granite, in quarries located in the heart of the Granite industry, in Elberton, Georgia. We were working with Georgia Institute of Technology (Georgia Tech) at the time and were asked if we could, at very short notice, go down to a couple of quarries and run a demonstration.

Back during my graduate studies I had found that Russian claims were true that said that it was possible, with a 10,000 psi jet pressure to cut through a rock with a compressive strength of 30,000 psi. (I'll tell you how later)

Figure 1. 9-inch thick block of granite drilled through by a 10,000 psi waterjet at Leeds University. It took over 30 minutes. (Summers, D.A., Disintegration of Rock by High Pressure Jets, Ph.D. Thesis, Mining Engineering, University of Leeds, U.K., 1968.)

Knowing this, and having a suitable pump at Rolla, our group ran some tests at the RMERC to get the angles right between the two jets that we were to use, and then, about a week later, we went down to Elberton and set up a system in the quarry.

Figure 2. Starting to cut a 1-inch wide slot in granite, pressure 14,000 psi, 90 rpm, linear cutting speed around 9 ft/min, areal cutting rate around 20 sq. ft./hour.( Raether, R.J., Robison, R.G., Summers, D.A., "Use of High Pressure Water Jets for Cutting Granite," 2nd US Water Jet Conference, Rolla, MO., April, 1983, pp. 203 - 209.)

The trials demonstrated that high-pressure water could cut granite at commercial rates, we cut a slot some 11 ft long and about 2-ft deep, and, after a couple of days of work, we went home. Georgia Tech then went to one of our competitors who set up to run a similar test. We had been done in 2 days, it took them two weeks to cut a slot about 2 ft long and 6-ft deep. They were running a jet system at 45,000 psi, roughly 3 times the pressure of our system. Why did they do so badly?

Well it turned out that they connected their pumps to the nozzle through a very narrow length of high-pressure tubing, and we calculated (as later did they) that of the 45,000 psi being supplied at the pump, some 35,000 psi had been lost in overcoming friction between the pump and the nozzle, As a result they were trying to cut the granite with jets at a pressure of 10,000 psi effective pressure, and it was much slower than our system which retained most of the 14,000 psi from the pump to the nozzle. (Hilaris, J.A., Bortz, S.A., "Quarrying Granite and Marble using High Pressure Water Jet," paper D3, 5th International Symposium on Jet Cutting Technology, Hanover, FRG, June, 1980, pp. 229 - 236.)

Now you may note that I said something about mistakes – it turns out that we had made an identical mistake a few years earlier and had added a second 10-ft length of narrow diameter tubing to the nozzle, and suddenly a system that had cut adequately with 10-ft of tubing did not work with 20-ft. The reason was the pressure loss in the tubing was too great at the longer length, and the pressure fell below that required to cut into the rock. (But at the shorter length we were drilling the hard sandstone at 12-ft/minute).

It is a very simple mistake, and many folk have made it over the years. The system has to be designed from one end to the other to ensure that all the parts are properly sized for the systems that are to be used. (And I will refer to other cases such as that above as we go through this series.)

It is not just the diameter of the feed lines that is important. In 1972 it took, on average, 150 man-hours and about $2,000 for the U.S. Navy to clean a single ship boiler using chemicals and mechanical scrubbing and cleaning. An enterprising company showed the Navy that it was possible to use waterjet lances to clean the tubes. In the demonstration they cleaned a boiler in 10 hours, and it cost around $700. This being Government work, the Navy then arranged a competition to find the most effective contractor. Based on the performance of the system that had been used in the first demonstration they asked 5 companies to compete in cleaning boilers. The operating equipment was designated as having to operate at 20 gpm, at a pressure of 10,000 psi. The results were not even close, even with systems nominally the same.

Figure 3. Relative cleaning efficiency in areal percentage cleaned, of five competing systems in cleaning heat exchanger tubes in Navy boilers. (Tursi, T.P. Jr., & Deleece, R.J. Jr, (1975) Development of Very High Pressure Waterjet for Cleaning Naval Boiler Tubes, Naval Ship Engineering Center, Philadelphia Division, Philadelphia, PA., 1975, pp. 18.)

One of the differences between the competing systems, you won’t be surprised to hear, was that some had smaller feed hoses than others.

There are many different reasons that the various systems performed as they did. One of the aims of this series is to ensure that, should you be asked to engage in such a competition, you will know enough to follow the path of company A, rather than company E.

As systems have become more sophisticated the different factors that control the performance of the jets have increased in number. As a simple example, when abrasive particles are mixed with high-pressure water in streams of abrasive-laden waterjets at pressures that can run up to 90,000 psi in pressure, for high precision cutting of material, the factors controlling performance now include not only the delivery system for the water, but also that for the abrasive, the type of abrasive and the configuration of the nozzle through which that final cutting jet is created.

Again, when we were asked to compare the performance of these different systems we set up nominally identical test conditions under which to determine which nozzle system would perform better. If I were honest I would tell you that before the tests began I expected that the variation in performance of the systems would vary by perhaps 10% between the best and the worst. We were quite surprised by the result.

Figure 4. Comparative performance between 12 nominally similar abrasive waterjet cutting nozzles in cutting through steel at a standard speed, pump pressure, and abrasive concentration.

I use these last two figures to show that all the details of a high-pressure waterjet system are important, when it comes to optimizing performance. One of the reasons to write this series is to ensure that folk that use these systems in the future do not make the mistakes that we made, as we learned how to tune the systems from getting poor performance to the commercially viable rates that are achieved today.

Unfortunately much of the early research and tests that are the basis for this knowledge were performed before the Internet existed. As a result I will have to use references to books and papers (as above) rather than using the electronic references that are the more common habit now.

This concludes the basic introduction to the series, which will now focus on more specific subjects.

OGPSS - An introduction to Iran

The theme of these posts, over the past eighteen months, has been to look at the leading producer nations that provide crude oil to the world, and see whether it is realistic to anticipate significant increases in their production. Posts have now looked at North America, Russia, Saudi Arabia and China based on the original list of rankings produced by the EIA in 2009. And, as I noted before beginning the China posts the interesting question at the moment relates to a) how much oil is Iran currently producing and b) how much, realistically, can it be expected to produce.

These are not questions with the same answer, since the current sanctions that have been imposed on the country have clearly already had an impact on the amount of oil that is being exported from Iran. Nevertheless the volumes produced have fallen below those now achieved by China, and for that reason China was given priority when it came to the order of writing these posts. But back at the beginning of 2011 there was no doubt that Iran was one of the top 5 producers (particularly if one combines the USA and Canada into the new “politically correct” term of North America as a way of dodging questions on long-term US production levels).

If one looks at the latest, September OPEC Monthly Oil Market Report (MOMR) for example, there is now a gap of 1 mbd between the official production claims, which are shown below, and the reports from other sources, which follow.

Figure 1. OPEC production reports, from the originating country (OPEC September MOMR )

Figure 2. OPEC production reports, as provided by secondary sources (OPEC September MOMR )

In passing it should be noted that OPEC is anticipating global oil demand to grow 0.9 mbd in 2012, and 0.8 mbd in 2013. To meet that OPEC anticipates that non-OPEC production gains will be 0.7 mbd in 2012, and 0.9 mbd in 2013, taking some of the pressure away from the OPEC producers. Within OPEC production, the gains from NGL’s are anticipated to further increase by 0.4 mbd in 2012, and 0.2 mbd in 2013. These figures again ease the need for OPEC to show increases in production to meet export demands, at the time that their internal consumption continues to rise.

Iran is thus, by the original criterion, the last of the Big Five to be looked at, although, in light of current production numbers it has clearly fallen into the second tier, and with current production below 3 mbd it joins others (Mexico and Veneuela, for example) who have fallen through from upper second tier into the lower second tier of nations that produce below 3 mbd, though this is likely transient, depending on how long sanctions last and, more critically, are effective.

If there is little likelihood of major increases in production from Russia, Saudi Arabia, and China, and that I take some of the optimism over North American production gains with a considerable grain of salt, then global increases in production must come from nations that are now producing below 3 mbd. With that size of an industry it is difficult to anticipate spectacular increases from a single producer. Rather individual country gains (with the exception of Iraq, which could increase production to 4 mbd) will likely only be perhaps on the order of 100 kbd. As a result, if global needs are to be satisfied, there has to be a whole series of overall gains in a multiplicity of countries. For it is only in this way that the total can combine to sustain the optimism of those who see a cornucopia of oil flooding our future through at least the next ten years.

That Iraq has moved into the second tier above 3 mbd this month (by both their own and other counts) makes it a separate point of discussion. But first there is Iran. And with President Mahmoud Ahmadinejad giving a more subdued speech before the UN this week as sanctions continue to bite, the role of crude in the Iranian economy may be becoming more evident to their government. Domestic consumption runs at about half of production, but the country needs the income from exports.

Figure 3. Iranian Oil statistics (Energy Export Databrowser )

Euan Mearns illustrated the range of Iranian oil facilities in his post last December prior to the embargo.

Figure 4. Iranian oil and gas fields and infrastructure (Euan Mearns at TOD)

Oil production in Iran has increased since the days in 2005 when, for a while, it appeared that the country had reached a point of declining oil production, and where natural gas injection was being debated as the possible answer. At that time as the debate over Iran “going nuclear” was beginning to build there was already a rationale for the development of nuclear power in the country.

Jump forward seven years and that debate is now at a much more intense level. The Israeli Prime Minister is seriously concerned over the development of nuclear weapons in Iran, as are other countries in the region, and around the world. The relative need for Iran to establish a nuclear-based electricity program, while used as a justification of the program by their government, has been largely neglected in the concern over the potential for weapons development. Sharing the largest gas field in the world (the South Pars: North Field) with Qatar, Iran has a resource that is being used at an increasing rate internally, with slight amounts being imported in the remote northern part of the country, where it is easier to use gas from abroad than to lay the delivery lines in country.

Figure 5. The South Pars: North Field Gas field shared by Iran and Qatar. (petroleum reports via The Encyclopedia of Earth)

Figure 6. Iranian natural gas statistics (statistics (Energy Export Databrowser )

And so, with the above as background, the next couple of posts will look at the Iranian situation in a little more detail.

Looking Indian and Red Paint Peoples - additional thoughts

Before moving on to the next period of possible European:Native American interaction, there are a couple of things to add to the narrative that has been compiled to date. First I had a short discussion with the lady behind the desk, while visiting the Abbe Museum in Bar Harbor. I had commented on their lack of identification of the Red Paint People, and she commented that they felt that using the term diminished the tribe, and made it easier to disassociate current Wobanaki (the collective tribe of North-East America) from their ancestors, and thus diminish any political clout they might have. Having picked up Frederick Wiseman’s Book “Reclaiming the Ancestors” in the museum shop, it provided additional information relative to my last post, and so I will return to the Wobanaki issue in a minute.

But the second point that I wanted to touch on was one made by Senator Scott Brown, in his first debate with Elizabeth Warren in this election cycle. He made the comment

“Professor Warren claimed that she was a Native American, a person of color, and as you can see, she’s not,” said Brown. . . . . .

Now this is where this series began. Because what does an Eastern American Indian (as the Cherokee and Delaware were) look like? I rather think that the good Senator is being either somewhat perhaps racist, or perhaps just ignorant? For the reality is that the average Native American of the Eastern seaboard look like the average American. The lady behind the counter, who from our conversation is likely Wobanaki had the appearance of a typical American teenager/college student. The five basket weavers whose work is featured in the museum at present are Indian but look no different from your average American. In fact the second from the left looks a little like the good Senator.

Figure 1. Indian Basketweavers whose superb work is on display at the Abbe Museum (Abbe Museum)

So Tsk! Tsk! Senator, perhaps you ought to have a good look at your constituents. (Note that this comment has now been picked up at Talking Points Memo).

To return to the Wobanaki, and Professor Wiseman’s book. (He is incidentally Wobanaki himself). One of the premises on which the series to date has developed lies on the assumption that there was communication between European and some of the first populations of America (the First Nations) possibly dating from the time period of the PaleoIndians, and also possibly at the time of the Red Paint People. Dr. Wiseman gives a First Nations view of the topic.

In addressing the first of these points, Professor Wiseman noted that at the end of the Last Glacial Maximum, PaleoIndians were using stone obtained from Ramah Bay in Northern Labrador. The significance of that, at the time I first read it, escaped me. But the distance from Ramah Bay to Maine is about a thousand miles and at the time of the use of the stone there was the remnant of a glacier still sitting over most of Eastern Canada, down to the coast.

Figure 2. Suggested trade route from Maine to Ramah Bay. (Google Earth and Frederick Wiseman.

The upshot being that the First Nations had seagoing craft, and that the “technology” therefore existed to allow communication along the lower edge of the ice sheets and glaciers, from America to Europe.

Figure 3. Alternate route to Ramah Bay (Stephen Loring via Georgiabeforepeople )

Wiseman suggests that the boats were hide covered, much as are the current umiaks used by the Inuit to move groups and their belongings over distance. Although if they were venturing long distances, I imagine they might have provided some cover for the passangers, and a variant of these has been around for millennia.

One addition that Wiseman brings to the cemeteries of the Red Paint People is that, in some cases the bodies were cremated. He cites the burials near Amoskeag Falls in New Hampshire, and also notes that as the culture moved from Early Archaic to Middle so the groups, which had originally only been the 20-30 individuals, the characteristic size of hunter-gatherer groups now grew. With the fish and marine harvests larger groups came together, and were able to construct fish weirs across the rivers, giving a much greater harvest, for less ultimate effort. Larger weirs use wooden stakes to guide the fish into the traps, while smaller ones, such as the Allman fish weir, were constructed of large stones. The weir acts to guide the fish into a trap, usually made of net or wood. The oldest of these is the Sebasticook Lake Fish Weir(pdf). When the larger weirs were placed in rivers such as the Penobscot, Wiseman notes that it might take perhaps more than a hundred man-days to construct the weir, since the staves had first to be shaped, and then held in place with stones.

Figure 4. Stones arranged across a stream to build a weir or guide so that the fish have to follow the narrow channel to the upper left of the stream, where traps can be set to catch them. (National Park Service)

I used the example of the Allman weir because it is a relatively shallow construction and was re-constructed by just one man. The more conventional weirs are made of wood, and are set into the river bed, albeit in roughly the same shape, but require much greater labor to construct, with the advantage that, where the waters are tidal, the yield can also be much greater. The stakes would then be connected by a wattle (woven branch) construction to direct the fish. Miller notes that the Sebasticook Lake weir was made up of some 630 wooden stakes. Wiseman notes that single hunter-gatherer groups, which might consist of up to 6 “families” would “work” over an area that might extend from 3 to 19 miles in distance, using different regions as the seasons changed. Moving to the construction of weirs with their provision of longer-lasting food supplies then became a pre-cursor to the subsequent shift into an agronomic lifestyle.

One additional facet of stone tool design also appears in the region during the time of the Red Paint People, and that is the ulu knife. These probably originated in the Inuit communities several thousand years ago and have a distinctive shape. Their presence in Maine confirms the likelihood of communication between the First Nations in the lower 48, and the Inuit who were living along the Arctic Coast.

Figure 5. Modern Ulu knife shape (Ulu factory )

The great warming that occurred during the time of the Red Paint People, taken with their increasing development of larger communities, and deeper water fishing, leads Wiseman to suggest that rather than Europeans coming to America, it is equally possible that exploring Wobanaki were the ones to cross the Atlantic, and brought back as, perhaps, a bride someone with the X variant in the mtDNA that then began its spread west. It is an interesting point of view, and one that is shared by the Curator at the Penobscot Museum at Lake Isle.

The direction of the communicating vessels will come up again in later posts.

The Native American Peoples of the Red Paint/Cemetery Complex/Maritime Archaic/Moorehead Phase and the Maasai

Browsing through Howard Terpening’s “Tribute to the Plains People”, his “Passing into Womanhood” caught, and held my eye. Not just from the theme, nor the way he creates a realistic sense of what might be. No, it was the small bowl of red ochre that sits by the mother’s feet, and the red paint that covers the young maiden as she moves through the ceremony.

Howard Terpening “Passing into Womanhood,” 1989.

Back in the time that Europeans arrived in the Americas for the last and culture-changing time, the first Native Americans that they met wore little more than a coating of red paint, the Beothuk, being one such example. It is a tradition that Robert Griffing has used in his paintings of the period.

2. Face painted warrior (After Griffing – Logan’s Revenge)

The use of red ochre – mixed with or applied over a grease is not, however, novel to the American tribes of the more recent past. 80,000 years or more ago South African archaeologists believe that the native inhabitants of the Blombos Cave were using red ochre for body paint.

The tradition has descended to its use by the Maasai in Kenya to the present time. So when did the tradition arrive in the Americas? It does not seem to have been a tradition with those that came across from Siberia via Beringia, and thence into Western America.

Instead those known as the Red Paint People now more scientifically referred to as the Maritime Archaic, appeared in the New England and Atlantic regions of Canada between 6,000 and 3,000 BP (years before the present). They first came to prominence when a local farmer turned up pockets of red ochre, and it was then discovered, first that there were polished stone tools within the pod of paint, and then further discoveries also found human remains, showing that the bodies had been buried with pots of ochre in the grave. Paeo-Indians are believed to have lived in Maine since around 11,000 BP,(pdf), with the change from the chipped flint to ground stone tools occurring with the transition to the Archaic Period. With that tradition also came the use of the ochre paint, and the initial naming of the culture as the “Red Paint” people. The ochre was generated by grinding local haematite ore. As well as being called the Maritime Archaic, the culture is also referred to as the Moorehead Phase. Cemeteries have been found only between the Kennebec and St John’s rivers in Maine. They include the Turner Farm site in Maine, and the Blue Hill Falls site with the Nevin shell midden.

Figure 3. Cemeteries if the “Red Paint” People in Maine. (Massachusetts Archaeological Society )

However, as investigators have looked for and found other sites, they have, to date, established that the earliest site was at L’Anse Amour site in Labrador. The site was occupied from 9,000 to 2,000 years ago, but the buried individual was a child laid to rest some 7,500 years ago.

The body had been covered with red ochre, wrapped in a shroud of skins or birch bark, and placed face down, head pointed west, in a large pit 1.5 metres deep. Evidence also indicates the use of ceremonial fires and the cooking and consumption of food. Offerings were made of tools and weapons made of stone and bone. These included a walrus tusk, a harpoon head, paint stones and a bone whistle.

. The burial grounds at Port au Choix in Newfoundland lie fairly close to this coastal site, and have the advantage of also including residual material from the nearby community. The site is younger than that at L’Anse Amour, dating to around 2000 to 1200 B.C.

More recently Red Paint burials have been found in Wisconsin, dating from between 1,000 and 400 BC. The later dates are about the time of the shift to the Early Woodland period of American history, when pottery was introduced. Grave sites have also been found in Michigan, Illinois, Iowa, Indiana and Ohio. So it would appear that, as with the Clovis Points, the concept started in the East and spread Westward.

Where did the idea come from? Well starting with the African culture cited above, Europeans have been burying people with ocher paint from the time of the “Red Lady of Paviland Cave.” That skeleton was, as it turned out, actually that of a young man, dating from around 30,000 years ago, back when there were still glaciers in the UK. It is the oldest “Modern human” skeleton found in the United Kingdom.

Given that, of one puts this chronology into sequence, this gives an African-European-Eastern American progression, there is an implication (through the L’Anse Amour connection) that, as with the Clovis Point, there was a European connection to North America along the Northern perimeter of the Atlantic.

L’Anse Amour also introduces funeral monuments to North America with the suggestion that it took at least a week for the local hunting band to build the mound, using local stone and boulders.

Figure 4. Artist’s Impression of the L’Anse Amour burial (Canadian Encyclopedia )

The mounds that followed, moving down into Maine seemed to be more incidental, since some of the burials were found in the large shell middens that were built as the community harvested and consumed the local shellfish over many years. At the Turner Farm site, built around 5,000 years ago, the shells are mainly of clams with the advantage that the shells reduced the acidity of the local soil, so that bones could be preserved.

This site has the oldest dates for human occupancy in Maine.

Two reasons have been proposed to explain the lack of older coastal sites. The first is that the sites were drowned or eroded as sea levels rose during the past 11,000 years (Sanger and Kellogg 1989; Kellogg 1995). The second is that the early Gulf of Maine was not highly productive, a result of low tidal amplitude and poor circulation, and that there were scant resources to support people in a maritime adaptation (Sanger and Belknap 1987). Evidence for the first scenario may be found in the rare artifacts that have been dragged up by fishing boats in the Gulf of Maine and associated estuaries (e.g. Spiess, Bourque, and Cox 1983; Wilson 1997). The second reason is much harder to confirm.

One conclusion from Maine coastal research is that the timing of the earliest visible occupation varies significantly along the coast, a result of localized rates of sea level rise and differential erosion rates (Sanger and Kellogg 1989). Another factor contributing to the pattern is that certain locations only became available for habitation when sea level had risen enough to make access possible and to create clam flats.

Research conducted to date shows that the oldest extant Maine shell middens are in Penobscot and Frenchman Bays, where soft-shell clams were procured as early as 5,000 B.P. In Casco Bay, the earliest dated occupation, about 4,000 B.P., was associated with oyster shells at the base of a large midden on Great Moshier Island (Yesner 1984). Basal deposits in the oldest Casco Bay shell middens are routinely composed of oyster and quahog (Loomis and Young 1912; Sanger and Kellogg 1989; Yesner 1983), species indicative of warmer waters and a lack of intense sedimentation. A decline in the rate of sea level rise, increasing sedimentation, and colder surface temperatures have been proposed to account for intensive coastal settlement and the formation of soft-shell clam middens after 2,000 B.P. in Casco Bay (Yesner 1983).

Interestingly the shell midden site at Taft’s Point at West Gouldsboro, ME, also included iron pyrite associated with the fire pits, the use of the pyrite as a fire starter is also considered a marker for the culture. The pyrite provided an early version of the steel which, when struck with a flint, was the source of sparks for the flint-lock rifle in later years, and historically provided the spark which was caught on tinder to provide the basis for a fire. Otzi, the remains of a man found in the Alps who lived 5,300 years ago used flint and pyrite as his fire starter.

At Blue Hill, which lies at the mouth of the Penobscot River, the Nevin shell midden was the first to be found that included human remains. Remains of a total of 19 separate individuals have been identified at the site, which covered the period from 4,500 to 3,800 BP, at which time the culture seemed to “disappear.” However shell middens continued to grow as coastal settlements continued to consume the local bounty, and the use of ochre in graves seemed to move West, as noted above. The change in cultures appears to be marked with the introduction of pottery.

Was this assimilation, or, as with later tribes, did the growth of the population cause the original inhabitants to “move on” as stronger cultures displaced them? We may never know, but – to return to the original motive for this short series – it does provide another point at which European customs appeared in an American setting, suggesting, from the chronology, that there may have been a European arrival perhaps 5,000 to 6,000 years or so ago. UPDATE The date is roughly about the time that there was a culture change in Britain, with the arrival of the Celts, the change from a worship of the moon to worshiping of the sun, and the start of construction of the stone circles, the most famous of which was Stonehenge. And, of course, there were druids and body painting, although, as those who remember the movie Braveheart will recall, the paint was wode, which is blue, rather than red.

Waterjetting 1c - Volume flow, horsepower and thrust tables

Over the course of my career there is one table that I have used, for one reason or another, just about every week. Most folk will not likely need it nearly that often, but it contains some information that can be handy, if it is suddenly needed.

The table provides the relationship between the pressure of a waterjet system, the size of the nozzle that the water is fed through, and the resulting flow rate that is being used, the horsepower of the jet, and the thrust that the jet will exert back on the equipment/person holding the nozzle.

It is a very straightforward set of calculations, and I will build the table in two parts. The first will be a line-by-line explanation of how the calculations are made, and what the basis is, and then I will provide a tabular format (which is the one that I use) from which values can be read off. Because this is built in Excel the values on the edges of the table are changeable, to fit your own particular set of needs. Construction of the tables will be given through a series of 30 steps.

I am going to write about the parts that make up a system to deliver water under pressure in later articles, and so some things that will be explained then are going to be just stated at this point. The first of these comes when one considers nozzle size.

A nozzle, at its most basic, is a hole of a fixed size. Under just the force of gravity flow is quite low, and to get more water to flow through that hole some pressure must be applied to the water. The very simple relationship between the pressure at which the water is pushed, and the resulting speed of the water is given by the equation:

Speed (ft/sec) = 12.5 x square root of pressure (in psi)

Please note that water starts to compress significantly at about 15,000 psi. For the sake of this initial set of tabulations I am going to neglect that issue, though it will come up at some future date.

1. Since pressure is a value that is often chosen by the operator, the value for pressure is entered into cell c3. For this example, a value of 10,000 is used. (These come from the first system that I worked with, back in Leeds in 1965).

2. The equation to determine the velocity of the water is entered into cell c4 as

[ =12.5*sqrt(c3)].

Because the units need to be consistent going through the calculation, inches will be used initially. So the initial velocity value is multiplied by 12.

3. To convert into inches/second, the value in cell c4 is multiplied by 12 in cell c5 using the equation:

[ = 12*c4]

4. Nozzle diameter is the exit diameter of the nozzle, and this is sometimes referred to as the orifice diameter. This is a selected value and is entered into cell c6. I am using 0.04 inches in the initial example.

The cross-sectional area of the orifice is given by the equation:

Cross-sectional area = π x (radius) squared

5. Orifice cross-sectional area is calculated in cell c7, by entering the equation:

[ = 3.1412*((c6/2)^2)]

As water flows through a hole, the stream does not flow out of the hole at the same diameter as the hole. As the flow enters the hole it necks down to a slightly smaller diameter, which is a function of the nozzle shape, among other things. The reduction is known as the Coefficient of Discharge for the nozzle, and is a specific value for an individual orifice that can vary from a value as low as 0.61 to a high of around 0.95 or better. This is an input value, based usually on a manufacturer’s statement.

6. Enter a coefficient of discharge value, I have used a value of 0.81, in cell c8.

7. Calculate the effective area of flow by entering the equation into cell c9.

[ = c7*c8]

By multiplying the area of the flow by the velocity (the length of the water column that flows through the orifice in a second) then the volume of water that flows through the orifice in a second is calculated.

7. Calculate the volume flow each second, by entering the following into cell c10:

[ = c9*c5]

The volume flow rate is normally required in gallons/minute, and the conversion is to multiply by 60 (to convert from seconds to a minute) and then dividing by 231 (the number of cubic inches in a gallon).

8. The calculation is made in cell c11.

[ = c10*60/231]

Computers calculate to a high number of decimal values, and to keep this in normal perspective I usually trim this to show either one or two decimal points. The value shown should therefore be 3.97 gallons/minute, and the table to date should look like this:

Figure 1. The basic steps in calculating the volume flow of water through a nozzle.

There are two other values that are useful to calculate. The first is the horsepower that is being used in the jet. This calculation is a straightforward multiplication of the pressure of the jet (in psi) and the flow rate (in gpm) divided by 1714.

9. Enter into cell c14 the equation:

[=c11*c3/1714]

The other equation that is often useful to calculate (particularly where lances are being held-held in cleaning operations) is the reaction thrust that comes back from the nozzle. Some years ago we validated in the laboratory that this value can be calculated from the equation:

Thrust = 0.052 x flow (gpm) x square root of pressure (psi)

10. Enter into cell c 16 the equation:

[ =0.052*c11*sqrt(c3)]

This gives the basic form for the calculation of the basic values that are most useful.

Figure 2. The initial individual values calculated for the flow.

(You might want to SAVE at this point).

However most of the time I want to do some comparisons and so instead of carrying out a single calculation I would like to see the values in a table.

To make the table I use the same basic equations that are given in the steps above, but I lay out a table of values for pressure and nozzle diameter, which I will step through for those who are less familiar with some of the features of Excel.

The first step is to enter the values that are going to be most useful. In a general table this starts with the pressure that might be used to clean the siding of a house.

11. Insert pressure values starting with 1,500 psi in cell b23, and continuing along the row to that which is used for some of the more intricate cutting of metal, at 90,000 psi, which is in cell L23.

12. The discharge coefficient value is set just above the table in cell c21. I am using a value of 0.81. since this is a common value to all calculations in this table, it is put in a place where it is easy to find and change where needed.

13. Nozzle diameter values are also input as a column down from A24 to A35. I have used values from 0.005 inches to 0.1 inches to cover the range of likely interest, though these can be changed, after all the tables are in place. (Those following along might use the values I provide to create the table, after which use your own values for pressure and nozzle diameter, and don’t forget to change the coefficient of discharge.)

The result, at this point should look like this:

Table 3. Basic structure of the flow calculation table

14. Now, in cell b24 (or the relevant cell in your table) enter the following equation, which combines all the different stages outlined above into one single step.

(=$C$21*(3.1412*60*(A24/2)^2*12*12.5*SQRT($B$23))/231)

The $ sign means that the location after the sign is a constant. It can be selected by highlighting the location in the equation (c21) and then pressing the command and T keys at the same time.

15. Now select the column of values that run from b24 to l24, and then use the Fill Right command under the Edit command in the menu. This will give a series of numbers in the shaded squared that can be ignored for the minute, since we are now going to go through and change some of the values.

16. Go to c24 and change the B24 to A24. Change the $B$23 to $C$23. Tab to D24 and repeat (i.e. change the C24 to A24 and $B$23 to $D$23), and continue doing this along the row, ending in cell L24 changing the K24 to L24, and $B$23 to $L$23). (This is just correcting the calculation to using the right nozzle diameter, and the right pressure values). The table should now look like this:

Table 4. The flow table with the first row completed.

And now take advantage of the power of the table.

17. Select the cells from B24 to L35, and then go to Edit -> Fill Down. The table should be filled in. (You might want to SAVE at this point).

Table 5. Full flow table.

The next step is to create the table for the fluid horsepower contained in the jet.

Because all the calculations tie back to one another from now forward, I am going to use a copy function for the pressure and nozzle diameter values, so that if these values are changed in the above table, they will also change in the dependant tables which follow.

The first step then is to insert the pressure and nozzle diameter values.

18. Go to cell A40 and enter

[=A23)

19. Select row 40 cells A40 through L40. Use the EDIT -> Fill Right command to copy the pressure values into the new table.

20. Select column A cells A41 through A52. Use the EDIT -> Fill Down command to copy the nozzle diameter values into the new table.

21. In cell B41 enter the equation: [=B23*B24/1714] select the B23 and press command T which will change the equation to: [=$B$23*A24/1714)

22. Select the B row from B41 to B52 and use the EDIT -> Fill Down command to generate the first column.

23. Go back to the values in cell B41 and remove the $$ signs from $B$23, hit return and remove the $$ signs from $B$23 in cell B42. Continue down the column removing $$ signs from the cells. The numbers in the cells should not change as you go down.

24. Select the cells from B41 to L52. Enter EDIT -> Fill Right. The second table will generate. While the cells are still selected reduce the number of decimal places to 2. SAVE the file. You have just generated the fluid horsepower table, which should look like this.

Figure 6. Fluid horsepower table.

We will now use the same technique to calculate reaction force.

25. In cell A57 enter [=A23]

26. Select cells A57 to L57. Enter EDIT -> Fill Right, to enter the pressure values at the top of the table.

27. Select cells A57 to A52. Enter EDIT -> Fill Down, to enter the nozzle values along the left-hand side of the table.

28. In cell B58 enter the equation for reaction force in terms of pressure and flow.

[=0.052*B24*sqrt(B23)]

29. Select the cells B58 to L58 and enter EDIT - > Fill Right.

30. Enter cell B58 and select the term B23. Press the command key and T at the same time, which will change this from B23 to $B$23. Tab and repeat this for the C23 term in cell C58, for the D23 term in cell D58 and so across the row ending with changing L23 in cell L58 to $L$58.

31. Select cells B58 to L69. Enter EDIT -> Fill Down. The table should be complete. It should look like this:

Table 7. Reaction Force calculation table.

Congratulations, you now have your own table, and by changing the pressure, nozzle diameter and discharge coefficient values along the flow volume table the charts can be tailored for your own conditions.

Iceland rumbles a bit

This is just a quite arrow to point to the number of quakes above a level 3 that have been happening in Iceland over the last few hours.

Earthquakes in Iceland as shown on the 20th September 2012 (Icelandic Met Office). (Stars are for earthquakes over a level 3, and turn yellow, from green, after 24-hours)

Not quite sure what it means, but Jón Frímann has more of a description of what is going on.

There is no more . . . yet!

OGPSS - China's energy and a conclusion

Although Energy Policy has not been a significant issue in the current political debate over who should be the next President of the United States, this has not been a particularly good month for that future. In August the Alaskan pipeline pumped an average of 399 kbd from the North Slope. As winter approaches that number needs to be above 350 kbd to ensure that there are no solids built-up within the pipe, and each year the numbers fall a little closer to that limit.

Just this past week Shell has announced that they will not complete any wells in the Chuchki Sea this year, but will only partially drill a number of wells, and leave completion until next year. This despite the fact that the Arctic Ice acreage fell to the lowest level in 33 years, the time over which these measurements have been made. Further over in Russia, the promised development of the Shtokman field, which has been postponed several times in the past, has again been put back on the shelf. The arrival of increasing quantities of shale gas, and the loss of the market to China have reduced the need, in the short term, for these supplies. At the same time the Russian government is, again, seeking support from Western companies for developments in East Siberia and offshore. They are, apparently, still courting BP.

Overall US Crude production has stabilized, following the impacts of Hurricane Isaac, but is not following the steadily upward production path that folks such as Wood Mackenzie would anticipate. That would require that the curve continue upward at a gain of around 0.5 mbd/year, which would be around the overall average for the gain this past year, but as a continuing slope, passing through the current apparent plateau.

US Crude Statistics for the week of Sept 20th 2012, (EIA TWIP)

It is this halt in the increase in oil production that is, perhaps, of the most concern to China (as well as the rest of us), since, while it can be shown that China has been able to provide for its future intermediate-term demand for natural gas and coal , they must have less confidence in their ability to sustain their growing demand for oil. The presumptive reason for that lack of confidence should come from a realistic assessment of their growth in demand, relative to the supply and demand scenarios for the rest of the world, Figure 1 playing some part in that realistic analysis.

The disagreements between China and Japan over island ownership in the China Sea is continuing to roil the waters. While the issue is nominally over who owns the Diaoyu/Senkaku Islands, the aggressive position that China is taking not only here, but also with other nations that border on the South China Sea show no signs of diminishing. Following a meeting between Secretary of Defense Panetta and the Japanese Foreign Minister Koichiro Gemba, the Japanese have stated that the US recognizes that the disputed islands fall within the purview of the U.S.-Japan security treaty. China, in response, is sending hundreds of fishing boats into the region, as well as official government ships that will monitor events.

“We will send monitoring ships in waves, and have them remain around the Diaoyu Islands at all times to display our will to defend our sovereignty,” the Chinese official said. The official added that the Fisheries Bureau will also work closely with the State Oceanic Administration.

According to the Fisheries Bureau, as of Sept. 19 more than 700 Chinese fishing boats were operating within 127 nautical miles, or 235 kilometers, of the Senkakus. Of these, 23 were within 60 nautical miles, or 111 km.

The official said commercial fishing boats will enter waters close to the islands at a time to be decided “based on the situation,” indicating that it will depend on Japan’s response.

Figure 2. Chinese fishing boats off the Senaku/Diaoyu Islands (Asahi Shimbun )

We are coming to the end of the period where increases in global demand for oil could be met by developing new reserves, or by expanding the production from older fields. Yet, while driving across America this past week, the amount of investment being made in repairing the interstate highway system, and expanding the number of lanes bringing cars into the cities shows that there is continuing commitment to automobiles and truck transport in the USA. (And as an aside there appeared to be more trucks on the road than I remember seeing in the past 3 or 4 years).

With a slow but significant re-growth in the American economy, certainly helped by the low price of natural gas, there remains a serious lack in viable alternative fuels to replace oil for use in transportation. Thus the demand for oil in America and Europe will continue to be sustained. It will continue to rise in those countries such as Brazil, Russia, China and India where automobile use has yet to fill the potential market. For the next few years Brazil and Russia can probably meet demand from their increased use of internal supplies, albeit by reducing exports. India and China, and their ilk, cannot.

Conflict over resources is, of course, not by any means new. Maschner and Reedy-Maschner have documented such conflicts in the Pacific Northwest during early arrivals of native peoples from Siberia, and conflict and warfare (as evidenced from skeletal remains) is pervasive throughout human history, from some of the earliest of times. (Stone weapon points found in mastodon skeletal remains are also found associated with some early human skeletal remains, showing that the tools were likely causes of the death of both).

The problem, however, that comes in the future is not just that the more powerful nations of the planet will need more crude oil resources than they can provide for their peoples on their own. It is that it will become more difficult to identify places where it is practical to carry out an invasion that will then provide the needed volumes for a given country. Evidence of recent conflicts (Iraq is a prime example) show that conflict makes resource recovery more difficult and delays levels of production that might be achieved if the conflict did not occur.

Perhaps the Chinese use of fishing fleets is an attempt to achieve its goals, without going to physical war. If so, it is unfortunate that the locations in which it can be deployed are likely to be few. Yet, at a time when most of the rest of the world appears unwilling to face the coming limitation on a vital resource, or to recognize that a problem might even exist, the Chinese awareness of the situation and their pro-active positioning of themselves to assure reserves ahead of other nations is beginning to be a greater concern.

Waterjetting 1b - Force, Pressure and Flow volume.

This is the second in a series on some of the ways in which high pressure water jets can be used. The series was introduced last week.

Back in September of 2012 archaeologists found the remains of the last king of England to die in battle. He was Richard III, to whom Shakespeare gave the line “a horse, a horse, my kingdom for a horse!” He died because a blow to his head was focused down to a very high local pressure, even though the overall force of the blow might not have been that great.

Figure 1. Gothic Armor of the type worn by Richard III. (Detroit Institute of Arts)

On the other hand, in the middle of Hurricane Katrina, seven years ago, a barge broke through the levee wall above the Lower 9th Ward in New Orleans, LA (NOLA) and released a wall of water that swept through the district. The pressure of the water was quite low, but the overall force it exerted demolished the buildings in its path, and swept them off their foundations for eighteen blocks back from the levee. In this case force, not pressure, was the cause of the damage.

Figure 2. The Lower 9th Ward in New Orleans after Katrina, as the water falls, it flows back into the Industrial Canal. The barge that broke through the levee is on the right. Most of the debris lined the second row of trees back from the levee. (Tulane)

It is this initial relationship between force and pressure, and the role that each has to play in the use of waterjets to remove material that form the topic not only for today, but in a number of the posts that will follow. Waterjetting applications now cover a wide spectrum of different uses, and finding the best choice of pressure and flow (which combine to give power) will change from job to job, and hopefully these posts will help make the choice easier.

It is raining outside. As the water drops hit the soil, the water soaks into the soil by penetrating along the existing cracks that exist between the grains of the soil. After a short time the water fills this space, and as it continues to rain, the impact of new rain drops hit the thin wedges of water that now run down into the soil. Although at much lower forces the action is the same as when you hit a wedge driven into a log with a hammer. The wedge pushes the two walls on either side apart, and a crack grows. One of the key elements that give waterjet cutting its advantage is this transformation from an impact force into a pressure, and most particularly a pressure which is applied against all the surfaces with which the water is in contact. It is a point that will be repeated many times.

Figure 3. The stages of soil erosion – the white arrows in (b) and (c) show the small pressures that are exerted on the particles as additional raindrops keep falling on the water in the ground. This lifts the top two particles in (c) so that the flow of water will carry them away.

With the soil there is not that much material holding the grains together, and so as the rain continues, the soil grains begin to separate from those on either side. Water gets underneath the grains and starts to lift the individual grains free from the mass. Since most land is not flat, the water will now start to flow away under the continued rain, and as it does it carries some of the soil particles that have been freed. This is a simple explanation for the erosion that happens in fields, dirt roads, and other exposed surfaces as they weather. As materials get stronger this process can take much longer to be seen. A high quality stone will erode at the rate of perhaps an inch every thousand years, depending on local weather patterns. There are buildings and bridges built by the Romans all over Europe to prove that point. A weaker granite (and one thinks of the granite in the walls of the Basilica in St Louis as an example) may severely erode within a hundred.

Which brings up an important point: the performance of a waterjet stream is not just controlled by what happens upstream of the nozzle in the delivery system, but it is also affected by the material that it is hitting. And I’ll come back to that in future posts.

First, however, consider what happened during Hurricane Katrina in the Lower 9th Ward. When the barge broke through the levee wall and was carried into the district, it rode on a wall of water that was initially no more than about 30 ft high. We can make a very crude estimate of the pressure of the initial wall of water (neglecting any impact due to the speed at which it moved) based on the height of that wave. A cubic foot of water weighs 62.4 lbs. It sits on an area of 12 x 12 = 144 square inches, so that the pressure under that water is 62.4/144 = 0.43 pounds per square inch (psi). Since that is somewhat close to half-a-psi, as a very simple way of getting the pressure at the bottom of a column of water one can just divide the height in two, and call it psi instead of feet.

So, in the case of that wall of water the pressure at the bottom of the wall would be 30/2 – 15 psi. Since the pressure increases with depth, the average pressure over the height will be half of that, or 7.5 psi. That pressure, by itself, does not appear that powerful.

But when the wave hits a building that pressure is applied over the entire wall. So if the building is 40 ft long and 10 ft high, then the area that sees that pressure is 40 x 12 x 10 x 12 = 57,600 square inches. If that small (7.5 psi) pressure is applied over the whole area, then the force = pressure x area = 7.5 x 57,600 psi = 432,000 lb.

You can now perhaps understand why, when the wave hit the first rows of houses in NOLA that they almost immediately disintegrated, and were carried back as broken debris for about ten blocks.

Figure 4. Aerial view of the Lower 9th Ward after the water had drained, and the levee had been replaced. For a sense of scale there is a school bus sitting partially under the barge, and that is the yellow dot at the end of the upper arrow. Each of the flat slabs to the left of the levee marks where a house stood. When we visited the site the house slabs were as shown, but there was still water – and some live fish, standing in the district. (Tulane )

This was a terrible disaster, but there are occasions, particularly in mining, where this terrible force, combining low pressure but high volume flow rates, can be harnessed to do useful work. Such flows are something that our ancestors have known for millennia, and were used as a way of mining from before the age of pumps, and l will tell how they did it in some later articles.

But in most cases we don’t have that amount of water, and the job is more often one where we want to precisely cut a hole, perhaps, in one of the walls of a building, rather than destroying the building. And we haven’t the patience to wait a hundred years to cut through a block of stone. So how do we speed it up? And so we come back to the death of King Richard.

Back in the day a foot soldier could make a bit of money in a battle by knocking a knight off his horse, and then holding him for ransom. The weapon that they used for this was generally known as a poleaxe. These come in various shapes, but one general idea was to have a hammer on one side of the long pole. Thus, by swinging the pole one could hit a knight with a force of say 50 – lbs. and this could knock him off his horse, allowing him – in the best of such worlds – to be captured alive and then ransomed.

Figure 5. Modern Reproduction of a poleax from about the time of the Wars of the Roses (Wallace Collection)

However that hammer head could measure about a square inch or two, and neither the force nor the pressure would have been enough to penetrate armor or a helmet of the type King Richard wore (Figure 1). To give the footman that advantage the design was changed to include a small spike in the center of the hammer.

Figure 6. Spiked Poleaxe from about 1582, (Royal Armories, Leeds) via My Armory.com)

Now when the force of 50-lb is applied through the hammer to the target it is not distributed over a square inch (giving a pressure of 50-psi). Instead it is focused down on a point that is less than a twentieth of an inch across. Total area of the circular point comes from pi x radius squared = 3.14 x 0.025 x 0.025 = 0.002 sq inches. Pressure applied through the spike to the helmet = 50/0.002 = 25,000 psi. That is enough for the spike to pierce through the metal helmet and the bone underneath, killing Richard III. Battle over, England had a new king, Henry VII, and the War of the Roses was over.

The intent of the two examples is to show how, in some circumstances, high volume flow rates at low pressure can do the most damage, and in others that much higher pressure applied over a much smaller area is the most effective. They are extreme examples but seek to illustrate the point, and in many cases neither extreme (highest pressure, lowest flow or lowest pressure, highest flow) will give the best answer. There are cutting conditions where operational concerns and benefits would argue that pressures of 90,000 psi, and flow rates around 1 gpm will be the best business choice. In other cases a flow of a thousand gpm, but at a pressure of 1,000 psi will be the most economic and viable way to remove soil, and weaker rocks like coal. This series is aimed, in part, at giving you the knowledge that will help you decide where, within that range, to make that balance, between flow and pressure.

(For those reading this series who are not that familiar with blogging conventions, the words that are highlighted in blue are links. So that if you want to read more about that specific topic, clicking on the highlighted words will take you to a web page that gives more information).

UPDATE: 1. This post was updated in 2013, after the body had been positively identified as that of the late King. The validation included a check on the DNA of the remains, which was compared with that of descendants of the family line.
UPDATE: 2. This post was slightly modified on April 19, 2013 to clarify some points that were not explained as well as I thought they were.

OGPSS - China's coal industry

In this run-up to the election, the American Energy future seems to have faded into the quiet background. Gone are the concerns of past years, as both parties seem to have bought into the idea that the nation is well on track toward a much reduced need to import oil. Wood Mackenzie are forecasting that tight oil production will rise from 1.5 mbd this year to 4.1 mbd in 2020, with the Bakken producing 1.3 mbd, the Eagle Ford 1.3 mbd, the Permian plays (Bone Spring, Avalon, Wolfcamp and Cline) will produce 440 kbd, and the Niobrara should be good for 90 kbd. With the decline in production from the impact of Isaac in the Gulf not yet over, it is not yet clear whether the plateau in US production that was starting to form will continue, or whether the gains in production that these projections require will continue. But there are some signs that these projections are, shall we say, a little ambitious. Well costs are now running in the $9 - $11.2 million range and, to sustain production, in these formations where wells have a high annual decline rate, increasing numbers must be drilled each year to offset that decline, and the poorer quality of newer wells. But declining rig counts and other concerns are for the future, and if no one coughs too loudly we can pretend that everything remains fine until we get past November.

China does not have that luxury, since the country, having set its people on an upwardly mobile quality of life path, must continue to provide the power that such a ladder requires. As I noted last time, the potential gains from the increased use of natural gas have been noted. Actions have already been taken to make sure that future supplies will meet anticipated needs and work has begun to tap the gas shales of the country.

But despite those efforts the underlying strength of the Chinese power industry comes from coal.

In 2007 Chinese coal production contained more energy than total Middle Eastern oil production. The rapid growth of coal demand after 2001 created supply strains and bottlenecks that raise questions about sustainability.

In 2010 China produced almost half of the world’s coal tonnage.

Figure 1. A decade of coal production growth (EIA )

China produced some 4.52 billion tonnes in 2011 and some 45% of that was shipped from the mine to the customer by rail. As demand continues to grow those volumes will also increase.

Figure 2. The changing picture of Chinese coal demand and production. (Energy Export Databrowser)

Rail takes a much longer time to install than does a pipeline, and thus Chinese recognition of this need is timely. Between now and 2015 Government plans call for an increase in transportation capacity to 3 billion tons/year almost doubling current capacity, as production of coal is anticipated to decline slightly to around 4 billion tonnes domestically, which may only exist as a target value. Nevertheless to move the coal to the power stations where it is needed, not only trunk lines, but also a large number of shorter branches will have to be created. This will be particularly true if the market shakes out and many of the smaller companies, which are apparently currently seeing some cash flow problems may fade out of business.

Figure 3. Planned expansion of the Chinese Rail network (China Coal Resource )

The Chinese have always been willing to find creative ways of improving their mining technology. I remember back some 45-years ago, when the European coal industry was still strong though waning, and the Chinese arrived seeking to purchase up-to-date mining equipment. Given that coal demand and thus equipment demand was in decline, manufacturers were willing to meet the conditions of the sale. These included that engineers and technicians be at the manufacturing plant during the entire time that the equipment was being built, and that they fully how understand the process. (The argument was so that they would be able to maintain it, after arrival). Well needless to say after those initial deliveries, further orders were rare, and Chinese versions of the equipment appeared, and many of those European manufacturers are no longer around.

New developments of technology in the West are much harder to come by these days. Research and innovation in coal mining in particular has fallen on hard times in both Europe and the United States (to the point of almost disappearance) and thus as China moves toward automation of its mining, particularly in thin seam conditions they are less able to draw on external sources, and must develop more of their own.

Life is a little different in other ways also, and Western companies can now get into the country and collaborate on development. Peabody, for example, is now developing coal mines in China. It has also been working with the government of Mongolia and will help develop mines in the Tavan Tolgoi region. This may be the only growth region for the company at a time when the current Administration in the United States, not to mention those in Europe, seem bent on closing the industry down as fast as they practically can. Given the amount of power that will be required to sustain current qualities of life, and the disappointing, and expensive costs of recent alternatives, the question as to how long this long-term unrealistic view will prevail is a matter of conjecture. China seems to retain a more realistic view of what is going to be needed, and planning accordingly.

There have been some thoughts given to the possibility of sequestration of all the carbon dioxide that will be generated from the various power plants that use this coal. However the power plants are not necessarily close to places where it might be easy to sequester the gas.

Figure 5. Location of the major Chinese coal-fired power plants (The American)

Figure 6. An integrated map showing the power plants (CO2 sources) and the fuel regions together with the location of deep saline formations into which CO2 could be injected (NYT )

The Oil Drum has been fortunate over the years to have had a number of high quality posts on the development of the coal industry in China. These include a review by Dr. Minqi Li, hosted by JoulesBurn. In this review of Peak Coal and China, Dr Li noted that Chinese coal production is projected to peak in 2027, at a level of 5.1 billion tonnes. He estimates a total ultimate recovery of around 257 billion tons. Euan Mearns wrote about Chinese Coal when their consumption first approached 50% of global demand, and followed that with a second piece on the role of imports.

In addition Rembrandt has recently taken note of the developing Chinese coal to chemicals industry. As conventional oil becomes less available as a feed stock, so the growth of this effort will likely justify the development.

Although China has, in the short term (perhaps the next ten to fifteen years) enough coal to sustain internal growth in demand, it is nevertheless also moving pro-actively to ensure that it will have adequate supplies in the out years. Much has been made in the past of their activities in Australia, but, as I have noted, several times in the past the Chinese are becoming well established in Botswana, inter alia, in a country with almost no coal industry yet, but up to 200 billion tons of what are not even counted as reserves yet, because of lack of demand. This may be a lesson for the rest of us.