Waxing, Paraffin wax

Paraffin is found in most types of mineral oils. Chemically paraffin is classified as hydrocarbon. The melting point is around 50°C and once it becomes solid or wax the range of the chemical formula is in between C20H42 to C40H82.
Technically the problem starts at lower temperatures. As seen above the melting point is about 50°C, once the temperature of the crude gets below this 50°, the paraffin starts to solidify and forming paraffin wax or just wax. This solid wax forms a layer inside the pipelines, and slowly the cross section of the pipe is getting lesser and lesser.

The crude comes normally at rather high temperature out of the ground. This temperature is than above the melting point and nothing or very little happens about waxing. But once the crude is transported a long way, the temperature lowers and the problem occur. Depending on the temperature of the oil, the temperature of the environment and the time the oil needs to be transported, the waxing starts. As longer hot crude is kept in an environment with lower temperature as more the crude cools out. This problem is seen more often in sub-sea lines, where the sea temperature even in hot areas of the world is below 30°, in areas where it is general cold, and in areas with a big difference in seasonal temperatures, the problems are increasing only during the cold time of the year.

Waxing can be found in the oil wells and of course in the flow-lines and trunk-lines connecting the wells with the treatment facilities further downstream. In a lot of oil fields, this wax has to be removed periodically, with a higher cleaning frequency in the cold months. In a well the cleaning is in most cases done mechanically. This is done by well services using wireline tools. The wireline run is repeated until the tubing is free of wax. This operation incurs well service cost as well as loss production form the well. This method of mechanical cleaning has another hidden cost. If the wireline is stuck then it could take time to clear it. This mean loss in production from the well.
In pipe lines there are two major ways of doing so. Either mechanically by pigging, or by introducing heat / steam in the pipeline or hot oil- to melt the wax again and transport it downstream together with the crude.
A pig is a mechanical device put in the pipeline, which is cleaning the inner side of the pipeline. It is driven by the liquid, itself and in very easy words, it is scratching along the inner surface of the pipeline and during this process removing the wax and or scale from the pipe wall. There are special receivers at the end of the line, where the pig is brought out of the line, and where all the sludge and other debris are collected. There are limits for using such pigs, this are the size of the line, but as well the design of the pipe line. If there are too many bends, or too sharp bends, it is not possible to use a pig, because the risk it will be stuck in the pipeline.
So for smaller pipelines the choice is to introduce energy and heat up the crude. This is either done, by putting heat exchangers in the pipeline where the crude is heated, the pipeline is heated all the time by electrical ways, or the pipeline will be steamed in a certain interval.
All these methods have one thing in common, they are very expensive, a lot of energy is needed in order to heat the crude, and a lot of service or maintenance is required.

Merus is able to lower this waxing significant.

In order to do so, Merus is installed at the beginning of the pipe line, and is under good conditions, able to treat 10 km down stream. The wax is kept in solution in the crude even at lower temperatures. So the amount of wax, and other debris, sludge or even sand is less in the pipeline. A positive side effect of keeping the paraffin in solution in the crude can be, there is less sand or other solids found in the sludge. Not that Merus is able to solve sand, but having less wax, there is less holding or settling points for insoluble ingredients and more of these are traveling downstream instead of adding to the scale formed by the wax.
As several case studies clearly show, there is significant less sludge, wax found after pigging. This leads to less frequent pigging cycles. There is also clear evidence in other studies, of less steaming or less heating of the pipe lines. In some cases there is no need at all to heat the crude.

Merus is able to save a lot of operating costs.

As an example: If a pipe line has to be pigged every second day, there are 15 pigging runs needed a month. Assumed one time pigging is costing 5.000 USD, this add to cost for the pigging of 75.000 USD a month.
Using Merus will bring down the amount of wax, and the pigging have to be done only every third day or even only every 5th day. Accordingly the savings will be 5 or 9 times pigging a month, which gives savings in between 25.000 to 45.000 USD a month.
In such a case the ROI of Merus will be in days.

 

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