AU2017100260A4

AU2017100260A4 - Transportation of a salt slurry in a density controlled nested pipeline system with slurry transportation in the inner line and transportation of the return brine in the annulus between inner and outer pipe.

Info

Publication number: AU2017100260A4
Application number: AU2017100260A
Authority: AU
Inventors: Theis Borchers; Michael Werner
Original assignee: Consalt Explor GmbH
Current assignee: Consalt Exploration GmbH
Priority date: 2017-03-04
Filing date: 2017-03-04
Publication date: 2017-04-06
Anticipated expiration: 2025-03-04

Abstract

Pipeline transportation system for crystalline salt with at least one pipeline nested within another pipeline in a way where the inner line is transporting a salt-slurry in one direction, while at the end of the transport system, the carrying fluid is separated from the salt crystals and recycled backwards through the annulus between the two or more pipes. The system comprises a mechanism enabling minimization of the friction of the inner pipe at the contact with the outer pipe through managing the buoyancy of the inner pipe by adjusting the fluid densities in the inner pipe as well as in the annulus. This will allow the easy removal of several kilometers of the inner pipe with simple pull-out technique, as well as pulling in a new pipe. -0 B,;ne trar-spoft SI.rry transport Fig. 1: Nested pipeline concept in operation Bdne transport ----------- ------------- ----------------- ------------------- ------------------- --------------------- --------------------- ---------------------- ----------------------- ----------------------- ----------------------- ------------------------ ------------------------ ------------------------ ------------------------ ------------------------ ------------------------ ------------------------ ------------------------ ----------------------- --------- -slurry Irabspwt - -------------------- -------------------- ------------------- --------------------------------- ------------- ----------- . . . . . . . . . . Fig. 2: Cross-section of nested pipeline concept in operation

Description

1 2017100260 04 Mar 2017

PATENT DESCRIPTION TITLE:

Transportation of a salt slurry in a density controlled nested pipeline system with slurry transportation in the inner line and transportation of the return brine in the annulus between inner and outer pipe. FIELD:

Solid salt transportation as slurry in pipelines.

BACKGROUND OF THE INVENTION

[0001] The definition of a salt-slurry is a suspended mixture of solid salt crystals and salt saturated water (brine).

[0002] Pumping salt/brine slurry is widely used common technology. However the transportation fluid, the brine, is drained off after the salt is separated or the brine is pumped back by a dedicated, separated brine pipeline system to be reused as transportation fluid for new slurry.

[0003] Solid particles in salt-slurry induce comparably high abrasion within the pipe, resulting in rather low life time. Furthermore, an online leak detection system is necessary but not easy to install and run. This is because of the inhomogeneity of the slurry in the pipe and the resulting sporadically and sometimes spurious pressure swings.

[0004] If in a conventional system the transporting brine has to be reused and recycled, it is necessary to install two separate pipelines. Whereas a brine pipeline has an expected long lifetime, e.g. it is made out of PE, the lifetime of a slurry line is very limited, and so it has to be replaced much more often. All of this is leading into high capital and operational cost.

[0005] Most of the disadvantages described under [0004] can be avoided by using a nested pipeline system - one pipe slid into another pipe. However, in a nested pipeline concept the inner 2 2017100260 04 Mar 2017 pipeline is very difficult to recover via pull-out technique due to high frictional forces because of the weight of the inner pipe. If this pipe is filled with slurry, contact and friction will be at the bottom. If the inner pipe and the annulus are filled with pure brine, the contact of a polyethylene (PE) pipe will be at the top of the outer pipe while a steel pipe will stay at the bottom. With this invention it will be possible to minimize the friction of the inner pipe through managing the buoyancy by adjusting the fluid densities. This will allow removing several kilometers of the inner pipe with simple pull-out technique, as well as pulling in a new pipe.

[0006] Prior to adjusting the buoyancy, the slurry line as well as the annulus should be flushed with either water, seawater or brine. A flushing with water or seawater will clean the pipes from solids by dissolving the salt.

[0007] Because salt slurry is abrasive, care has to be taken to monitor the integrity of those slurry lines. With the slurry line being nested in an outer pipe, the leak monitoring can be done simply by monitoring the differential pressure or flow of the inner line and the annulus.

SUMMARY OF THE INVENTION

[0008] This invention describes the pipeline transportation system of solid salt and liquid salt water (brine). The pipeline system consists of an inner pipe for transporting the slurry and an outer pipe for the transportation of solid-free brine within the annulus of the inner and outer pipe. The transportation fluid, the brine, is drained off after the salt is separated at the end of the slurry line. During normal operation of the pipeline system, this brine is flowing back through the annulus and can be reused to be mixed with solid salt to make up a salt-slurry.

[0009] As the life time of the slurry pipe of the nested pipeline system is limited, this part needs to be replaced from time to time. With this invention it will be possible to minimize the friction of the inner pipe through managing the buoyancy by adjusting the fluid densities. This will allow removing several kilometers of the inner pipe with simple pull-out technique, as well as pulling in a new pipe. The lifetime of the outer pipe is not impacted by the slurry operation, because the annulus is not carrying any solids. 2017100260 04 Mar 2017 3 [0010] After the cleaning as described in [0006], the pipe and the annulus will be flooded with brines of different densities. If the inner pipeline is made of polymer material like polyethylene a lower density fluid in the annulus will result in floating of the inner line, so the friction will be minimized. If the inner line is made out of steel, the density within the annulus has to be greater compared to the densities within the steel pipe. Depending on the steel wall thickness the pipe might not float, but the friction at the bottom will be greatly reduced.

[0011] The mechanism enabling minimization of the friction of the inner pipe at the contact with the outer pipe through managing the buoyancy of the inner pipe by adjusting the fluid densities in the inner pipe as well as in the annulus can be either computer software controlled or manually adjusted.

[0012] Construction of a nested pipeline system as described above requires less capex, because it is much less labor and capital intensive to put an inliner into an existing pipeline, rather than doing the earthworks to build a pipeline in parallel.

[0013] The necessary replacement of the inline pipe, the slurry pipe, can be done almost without field work. This results in a very low environmental impact and low replacement capex requirement.

DESCRIPTION OF EMBODIMENTS

[0014] The invention can be used with other pipeline materials than steel and polymer.

[0015] The invention can be used with multiple inline pipes.

[0016] The invention can be used transporting other salts than NaCl and the equivalent brine.

Claims

1. Pipeline transportation system for crystalline sodium chloride (‘salt’), said pipeline system comprising: at least one pipeline nested within another pipeline in a way where the inner line is transporting a salt-slurry in one direction, while at the end of the transport system, the carrying fluid is separated from the salt crystals and recycled backwards through the annulus between the two or more pipes; a mechanism enabling minimization of the friction of the inner pipe at the contact with the outer pipe through managing the buoyancy of the inner pipe by adjusting the fluid densities in the inner pipe as well as in the annulus in a manner which will allow removing several kilometers of the inner pipe with simple pull-out technique, as well as pulling in a new pipe.

2. Pipeline system as of claim 1, wherein the pipeline material can be made of plastic polymers or steel or a mixture of both.

3. Pipeline system as of claim 1, wherein also potassium and/or magnesium salts and the equivalent brines can be transported.

4. Pipeline system as of claim 1, wherein the mechanism enabling minimization of the friction of the inner pipe at the contact with the outer pipe through managing the buoyancy of the inner pipe by adjusting the fluid densities in the inner pipe as well as in the annulus can be either computer software controlled or manually adjusted.