Chemistry of hydrocarbon compounds – Purification – separation – or recovery – By addition of extraneous agent – e.g. – solvent – etc.
Patent
1994-07-22
1995-12-19
Gibson, Sharon
Chemistry of hydrocarbon compounds
Purification, separation, or recovery
By addition of extraneous agent, e.g., solvent, etc.
585867, 95149, 95187, 95229, 95237, 422243, 422291, C07C 710, C07C 700
Patent
active
054769868
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention concerns a method for cleaning a mixture of air and vapour from volatile crude oil with recovery of the hydrocarbons.
The invention also concerns a system for use in the method.
Volatile crude oil has a high vapour pressure at normal temperatures both in summer and winter. The high vapour concentration above the crude oil entails that a considerable loss occurs owing to the evaporation in the handling of the oil, e.g. in the filling of storage tanks. It is clear that it is of extremely great importance to reduce theses losses, both for economic reasons and for working environment and safety reasons.
Therefore, a plurality of methods aiming at reducing such losses have been developed in the course of time. Thus, the Danish Patent Application 0257/83 discloses a method and a system for recovering petrol from a mixture of petrol vapour and air by absorption of the petrol in a cooled petroleum distillate having a higher boiling point range than the boiling point range of the petrol. The petroleum distillate is successively cooled by heat exchange with a cold reservoir, brought into direct contact with the mixture of petrol and vapour to absorb the petrol, transferred to a buffer tank and transferred further to a stripping means which may be a distillation column. When thus cooling condensation and absorption of the petrol vapour are combined and the amount of cooled petroleum distillate brought into contact with the mixture of petrol and air is controlled so that the petrol concentration in the petroleum distillate transferred to the buffer tank is substantially constant, excellent optimum control of the petrolum absorption process is obtained, both in average load operation as well as in peak load operation. Reference is made to the above-mentioned Danish patent application for more detailed process and apparatus features.
In spite of its advantages, such a recovery system has certain drawbacks, one of the greatest being that the system takes up rather much space. In connection with oil exploitation from drilling platforms on the open sea it would thus be an advantage if the volatile hydrocarbon vapours could be recovered already when the volatile crude oil is pumped into tankers, but the large dimensions of the system known from the Danish Patent Application 0257/83 makes it less suitable for installation on a tanker. Furthermore, it is difficult to obtain a sufficiently high effeciency with the known system when the content of methane and ethane is high.
SUMMARY OF THE INVENTION
It has now been found that in connection with hydrocarbon vapours which occur in large approximately constant amounts, in high concentrations and over extended periods of time it may an advantage partly to precompress the vapours in the performance of the method known from the Danish Patent Application 0257/83 , and partly to let the system operate under pressure.
This results in a reduction in volume in relation to the known method, because the vapours under pressure occupy less space. It is moreover possible to recover vapours from liquids, e.g. very volatile crude oil, with high gas contents, because the increased pressure makes it possible to handle such increased gas contents.
Accordingly, the invention concerns a method for cleaning a mixture of air and vapour from volatile crude oil with recovery of the hydrocarbons, wherein the vapours are absorbed in an absorption means by direct contact with a petroleum distillate, which has been sufficiently cooled beforehand to cause combined cooling condensation and absorption of the hydrocarbons, said petroleum distillate with a substantially constant hydrocarbon concentration being transferred from the absorption means to a buffer tank and from there being either conveyed to a stripping means in which the hydrocarbons dissolved in the petroleum distillate are stripped so that the petroleum distillate circulates in substantially closed circuit, or being passed on for further processing or use. The method of the invention is characte
REFERENCES:
patent: 4475928 (1984-10-01), Jacobsen
International Search Report dated May 4, 1993 for Application No. PCT/DK93/00035.
Gibson Sharon
Phan Nhat D.
LandOfFree
Method for cleaning a mixture of air and vapor from volatile cru does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for cleaning a mixture of air and vapor from volatile cru, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for cleaning a mixture of air and vapor from volatile cru will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-993006