The Case for Capsule Pipelines

Calliban · 2024-09-25 08:46:24

Freight transportation is heavily dependant upon liquid fuels, more specifically diesel fuel. The slow depletion of easily accessible oil has made diesel more expensive with time. Since the early 1970s, this has imposed a steadily increasing drag on economic activity. For this reason, it is wise to consider options for freight transportation that reduce reliance on diesel fuel.

The option presented here is capsule pipelines. The concept describes freight transported in sealed, neutrally bouyant capsules. These are carried through a water containing pipeline by the flow of the water. The baseline concept considered here is a concrete pipeline some 2m (6.5') in diameter, carrying capsules some 1.8m (5.85') diameter and 4m (13') long. The baseline flow rate through the pipeline is taken to be 3m/s. The capsules are 4m long, with a 4m gap between them.

The energy consumption of the pipeline can be calculated using the Darcy-Weisbach equation. One of the inputs to this equation is friction-factor, which requires an estimate of Reynolds number. For flow through pipes, Reynolds number is given by:

Re = density (rho) x average flow speed (V) x diameter (D) / dynamic viscosity (mu).

Rho ~ 1000kg/m3 and mu =1.31E-3 N.s/m2

For the gap between the capsules: Re = 1000 x 3 x 2 / 1.31E-3 = 4.58E6

For flow through the gap between the capsule and pipeline, average fluid velocity will be one half the flow velocity between the capsules, or 1.5m/s.

Re = 1000 x 1.5 x 0.1 / 1.31E-3 = 1.15E4

The pipe is assumed to be smooth concrete, with a surface roughness of 0.025mm.
https://enghandbook.com/thermodynamics/ … lculation/

This gives a relative roughness of 1.25E-5 for the open pipe between the capsules and 2.5E-4 for the gap between the capsule and pipe. Applying the Darcy-Weisbach equation to the gap between the capsules:

dP = Fd x Rho x V^2 / 2 x Dh = (0.01 x 1000 x 3^2) / (2 x 2) = 22.5Pa.

The force required to drive the fluid through each metre of the pipe would be:

F = pi x r^2 x dP = 70.7N

For the gap between the capsule and pipe:

dP = Fd x Rho x V^2 / 2 x Dh = (0.019 x 1000 x 1.5^2) / (2 x 0.1) = 213.75Pa.

The force required to drive the fluid through each metre of the gap would be:

F = 2 x pi x r2 x (r1 - r2) x dP = 134.3N

Assuming a 3m/s flow speed and a 4m gap between 4m long capsules, the power consumption of each metre of pipeline is:

W = F x D = 0.5 x (134.3 + 70.7) = 102.5W/m.

Each capsule has diameter 1.8m and has the same density as water. The mass of reight transported by each capsule is therefore 10.18 tonnes. At 3m/s flow speed, the freight transport across each metre of pipeline will be 1.9085 tonnes per second. The amount of energy needed to push each tonne of freight through 1m of pipeline is therefore:

Q = 102.5 / 1.9085 = 53.71J / tonne-m = 53.7KJ/tonne-km.

How does this compare to other forms of freight transportation?

Wiki estimates an energy cost of 410KJ/tonne-km for rail freight in the UK.
https://en.m.wikipedia.org/wiki/Energy_ … rt#freight

So transporting freight through water filled pipelines at 3m/s would have about 1/8th energy cost of rail freight transport and 1/45th the energy cost of road haulage (2426KJ/t-km).

One important benefit of this concept is that no liquid fuel is needed to provide the pumping power. Only mechanical energy is needed. In fact, the energy needed to pump the water could be provided by simple vertical axis wind turbines. These would not need to generate electricity and could use direct mechanical power to pump the water. As we are pumping water at low speeds that are comparable to average wind speeds, these turbines would not need gearing. The vertical shaft would be directly coupled to a simple centrifugal pump design. This means only one moving part. The only significant wear item would be the thrust bearing that carries the weight of the shaft. The whole machine can be made from a mixture of wood, rammed earth, cement and local stone. We need 102.5kW of pumping power per km to keep the pipeline flowing at 3m/s.

The main downside of this concept is time. If we wanted for example to ship freight from New York to Chicago (1144km), it would take 4.4 days at 3m/s. Long Beach, Ca to NY is 7417km. It would take 28.6 days to ship that far by pipeline.

Last edited by Calliban (2024-09-25 09:23:42)

tahanson43206 · 2024-09-25 10:51:54

This post is reserved for an index to posts that may be contributed by NewMars members over time.

I am delighted to see this interesting and promising concept among the topics to be developed by the NewMars forum. It has potential for applications at locations other than Earth, taking into account differences in the environment and materials that might be used.

The concept has room for variations to overcome various local challenges, and this topic is a great place for solutions to appear, along with problems to be solved.

(th)

kbd512 · 2024-09-25 13:27:51

Calliban,

The correct answer to an increase in shipping times is actually having local stockpiles of goods in a warehouse. Prior to just-in-time supply chains, a store didn't "just have" what you saw sitting on their shelves. They always had a warehouse in the back of the store with additional stock. Wal-Mart still does this. You want inventory on the shelves for customers to buy, but as the COVID pandemic proved, having additional stock means your business isn't shut down inside of two days when, not if, a supply chain disruption happens. It also means your customers know you're a reliable provider, because you have stock, so they'll come to you first before moving on to the next store. Certain kinds of foodstuffs and pharmaceuticals still need to be shipped by rail, truck, or even aircraft to prevent spoilage, but the vast tonnage of goods are not going to "go bad" because they took a little longer to arrive.

This method, however slow, is the most energy-favorable solution for shipping low value but heavy goods between cities and continents. Iron ore is very heavy, but also very low value, and it doesn't "spoil" as long as it's kept dry. The only major cost is pipeline construction, after which it can run for a century. It requires no advanced computer control technology to function, so it's reliable in a way that electronics and electrical systems never will be.

Terraformer · 2024-09-25 14:06:13

Been meaning to create a thread for the rail version of this. Pipelines can achieve crazy high throughout compared to other means of transport for a given amount of land, because all the land is used. Putting rails in one would be more complex than water, true, but it would also remove the need for a flat route? I've been envisioning something around 60cm diameter, with 200L standard polythene containers for goods that can tolerate being bumped around, like pasta or butter or giant rolls of toilet paper.

One thing that could be good for pipeline transport of solid cargo is submerged floating tunnels. If what's being shipped is grain or iron ore, in automated trains, we don't have to worry about getting the safety perfect to avoid loss of life, and a breakage also shouldn't cause an environmental disaster as oil would.

Come to think of it, at low speeds a cable system could be used to propel the trains. The lead "locomotive" would grab on to a cable moving at idk 5m/s. Would have to be compared against powering it with omboard motors and a third rail.

Calliban · 2024-09-25 15:42:18

It is difficult to beat the exceptionally low rolling resistance of steel wheels on steel rails. If we look purely at the energy cost of overcoming friction for payload, ignoring carriage weight, air resistance and propulsion efficiency, the energy cost of moving payload by rail would be:

Q = Fd x D = m x g x Crr x D = 1000kg x 10 x (0.001 > 0.002) x 1000m = 10 - 20KJ/tonne-km.
https://www.engineeringtoolbox.com/roll … _1303.html

That is even better than what we calculated for pipeline transport. Some possible reasons that rail ends up looking less efficient than ideal, are:

1) The considerable empty mass of the train and carriages, which increases rolling resistance;
2) Some contribution from air resistance - freight trains on UK railways often tear along the track at stupid speeds;
3) Diesel engines are only 40% efficient;
4) Curves in the track substantially increase effective friction coefficient, as well as track wear;
5) Different parts of railways have different speed restrictions. Freight trains do not typically recover braking energy.
6) Do energy costs account for embodied energy in infrastructure?

We could design small guage rail systems to reduce a lot of these energy losses. Rail will always be faster than pipeline transport, because friction is inherently lower. One problem with smaller guage rail is that rolling resistance coefficient declines with increasing wheel diameter. So small wheels will have higher values of Crr. However, smaller wheels are also lighter and smaller carriages will experience lower bending moments in their chassis. So the carriages will be much lighter as well.

My hunch is that compared to a hydraulic pipeline, a pipeline carrying a small guage railway would give us higher speed for a comparable energy expenditure. But the engineering costs will be higher, because complexity of rail based systems is greater than a simple pumped capsule train. Which is best would need to be answered by a detailed engineering study accounting for costs and benefits.

Last edited by Calliban (2024-09-25 15:57:47)

Terraformer · 2024-09-25 16:05:40

Well, I wasn't imagine steel *rails*. Just one steel rail, with either an upper supporting rail to balance it or a pair of side rails. The weight would be borne by the steel rail. Of course, for bulk cargo we could also set up a Lartigue Monorail on poles. Balancing sacks of rice or iron ore should be a lot easier than balancing people or cattle.

https://en.m.wikipedia.org/wiki/Lartigue_Monorail

I do think there's a market for a lightweight portable lartigue system for things like festivals. Lots of stuff needs to be moved across usually muddy fields for those.

In 2022, Britain moved 216 billion tonne-km of freight. If that had cost 50kJ/tonne-km, 1.1e16J would have been consumed, around 3e9kWh. Around 400MW average power consumption. Potentially doable even with biofuels lol.

Last edited by Terraformer (2024-09-25 16:24:40)

Calliban · 2024-09-25 16:16:08

Precast concrete pipes of the right internal diameter (1.8 - 2.1m) are already in production for storm drains and sewer systems. We should be able to use these without modification.
https://www.jdpipes.co.uk/products-and- … crete-pipe

The capsules themselves could be HDPE or die pressed mild steel. In the second case, corrosion resistance could be provided by drip galvanising or coating with HDPE. One of the ends of the capsule could be flanged, allowing a lid to be bolted on with a gasket seal after loading.

Ideally, the capsule design would allow capsules to be loaded onto truck trailers at receipt facilities. That way, the capsule receipt faciluty is a node that can serve all businesses and customers within, say, a radius of several miles. The idea of an electric (or other stored energy) truck is much more achievable if that truck has a required range of 10 miles, instead of 300 miles. So ideally, truck transport should be limited to short distance haulage.
********************

Additional: These simple wind powered archimedes screw pumps were once common in the Netherlands.
https://en.m.wikipedia.org/wiki/Tjasker

They work well if the wind comes consistently from one direction and low head pumping is needed. We could improve blade design using modern tech I think. A flow speed of 3m/s is equivelent to a water head of <0.5m. So the Tjasker would work for our purposes and would be easy to build using local wood.

A power of 400MW to transport an entire nation's freight is a bargain. That works out at about 6W per capita. That is an insanely low energy expenditure for moving an entire nation's freight.

Last edited by Calliban (2024-09-25 16:58:05)

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The Case for Capsule Pipelines

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