Thermal measuring and testing – Thermal testing of a nonthermal quantity
Patent
1999-03-16
2000-06-20
Bennett, G. Bradley
Thermal measuring and testing
Thermal testing of a nonthermal quantity
73 30, G01N 2500, G01N 902
Patent
active
060769610
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a procedure for determining the low-temperature stability of a hydrocarbon mixture of the gas oil, fuel oil or crude oil type.
This procedure may be used to determine the stability of a gas oil which, on cooling, separates into two phases because of the crystallization followed by sedimentation (or creaming) of solid paraffins or waxes within the hydrocarbon mixture.
This procedure is particularly suitable, in the oil industry, for measuring the sedimentation of waxes in gas oils.
Most crude or refined hydrocarbons contain quite a high proportion of n-alkanes, called paraffins. These paraffins, due to the effect of a drop in temperature, can undergo crystallization and then sedimentation and thus cause malfunctions in the engines (gas oil), heating installations (fuel oil) or pipelines (crude oil) where these hydrocarbons are used.
Thus, the possibility of predicting the conditions under which an apparently homogeneous liquid hydrocarbon might separate into two phases is a considerable advantage for the optimum use of this hydrocarbon.
For example, when the temperature of a gas oil is lowered to between 0.degree. C. and -30.degree. C., the fact of knowing below which temperature the heavy phase crystallizes and of knowing how it does so, the light fraction remaining in the liquid state, makes it possible to fix the conditions of storage and of use of this gas oil so that it remains in the form of a homogeneous liquid phase. Thus, it is possible to prevent pipes and filters from becoming blocked and to avoid the pumping difficulties manifested by unstable operation of diesel engines.
There are several characteristic temperatures of gas oils: the cloud point or temperature at which the first wax crystals appear, the cold filter-plugging point (CFPP) or temperature at which a filter of standardized mesh size becomes blocked, and the pour point or the temperature below which the liquid cannot flow.
Waxes are found in all heavy hydrocarbons, such as domestic fuels, heavy fuels, crude oils and bitumens, and also cause filtering, pumping and blocking problems, especially in industrial and domestic boilers. In the case of domestic fuel oils, it is common to speak of summer fuel oil and winter fuel oil depending on their acceptable wax content during these periods.
In order to prevent the appearance of the phenomenon of crystallization followed by sedimentation, additives, whose function is to delay the appearance of crystals, prevent their development, keep them in suspension or prevent their sedimentation, are added to the hydrocarbons. It is therefore important to measure the impact of these additives on these phenomena.
There are several methods for measuring the parameters which characterize the appearance and separation of a solid phase within the liquid.
One method is based on measuring the weight of solids, such as waxes, in gas oils that have crystallized at a given temperature. These waxes are extracted from the hydrocarbon by centrifuging (Patent EP-0,355,053 A2) or by agglomeration of the waxes in a gravity settler (U.S. Pat. No. 4,357,244). These tests only make it possible to determine the total amount of waxes that have crystallized and are able to settle out. They give a measure of the sedimentation by excess.
A second type of test simulates real-time sedimentation in small containers (NF M 07-085 standard) in which hydrocarbons are stored at low temperature for 24 or 48 hours. The appearance and volume of each phase are then visually assessed by the tester, in particular the position of the interface between the two phases. These tests give an approximately qualitative measurement of the sedimentation.
These methods have drawbacks and inadequacies. They are lengthy, since they generally last 24 hours or 48 hours, and are not reliable since they depend entirely on the subjectivity of the observer. But above all, they do not make it possible to measure the amounts of the separated phases, nor to determine the rate of separation of the phases, nor even to explain and q
REFERENCES:
patent: 3045472 (1962-07-01), Paulik et al.
patent: 3055206 (1962-09-01), Watson et al.
patent: 3135107 (1964-06-01), Paulik et al.
patent: 3438248 (1969-04-01), Taylor et al.
patent: 4425810 (1984-01-01), Simon et al.
patent: 4489592 (1984-12-01), Pacanowski et al.
patent: 4538447 (1985-09-01), Pravda
patent: 5400642 (1995-03-01), Salvador Palacios et al.
patent: 5813767 (1998-09-01), Calabro' et al.
patent: 5844151 (1998-12-01), Brown et al.
Claudy Pierre
Faure Yann
Letoffe Jean-Marie
Mallet Catherine
Vassilakis Despina
Bennett G. Bradley
Elf Antar France
Verbitsky Gail
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