JPS62279826A - Method of recovering hydrocarbon vapor from mixed gas - Google Patents

Abstract

PURPOSE:To prepare and recover hydrocarbon vapor effectively from air by absorbing gas mixed with hydrocarbon vapor into liquid stored in a tank after being pressurized, by having gas not absorbed contact a gas separating membrane and exhausting gas not yet permeated. CONSTITUTION:Mixed gas 1 of gasoline and air is pressurized up to 2-3kg/cm<2> G together with return gas 10 coming out of a gas separating membrane device 7 and sent to a suction column 3. Mixed gas coming from the bottom of the suction column 3 rises up inside the column, contacts gasoline supplied to the upper section of the suction column 3, absorbed and recovered. Mixed gas 6 discharged out of the upper section of the suction column 3 is sent to the gas separating membrane device 7, and gasoline vapor is permeated by making the low pressure side a negative pressure of around 150Torr by a vacuum pump 9. Permeated gas, as return gas, is transferred to a gas compressor 2 together with mixed gas 1. Gas not yet permeated is dispersed into atmosphere.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention "Object of the Invention" The uninvented invention relates to a method for recovering hydrocarbon vapor from mixed gas,
The present invention aims to provide a method for economically recovering hydrocarbon vapor from a mixed gas of air and hydrocarbon vapor using relatively simple equipment.

Industrial Applications Technology for separating and recovering hydrocarbons from a gas mixture of hydrocarbon vapor and air.

Conventional technology Volatile hydrocarbons such as gasoline, kerosene, benzene, alcohols, etc. are filled into storage tanks, tank trucks, tank cars, etc., or when the temperature rises, mixed gases containing hydrocarbon gases are released into the atmosphere. It was just being dissipated.

However, the gases released into the atmosphere in this way are considered to be one of the important causes of air pollution as photochemical smog generating substances, and the emission concentration of the gases is being regulated by each local government.

However, there are methods for recovering volatile hydrocarbon vapors such as the absorption method, the rejuvenation method, and the deep-cooled cE compaction method, but for -C, the absorption method at room temperature and normal pressure is often used. ing. This absorption method, for example, as disclosed in Japanese Patent Application Publication No. 52-39785, involves absorbing gasoline vapor into an absorption liquid made of a non-volatile petroleum-based organic liquid under normal pressure, and then sending the absorption liquid to a regeneration tower and using a vacuum pump at a pressure of 25 Torr. The gasoline vapor is released under a negative pressure of about 100 ml, regenerating the absorption liquid, and the released gasoline vapor is absorbed into the gasoline liquid and recovered. Alternatively, as in U.S. Patent No. 4,043,769, a gasoline vapor mixture pressurized by a gas compressor is absorbed into a gasoline liquid and recovered, and the gasoline vapor remaining in the mixture gas is further absorbed into a non-volatile petroleum-based organic liquid. Then, the absorption liquid is brought to a negative pressure of about 125 Torr using a vacuum pump to remove gasoline vapor for regeneration, and the separated gasoline vapor is returned to the first gas compressor inlet.

Problems to be Solved by the Invention However, in the conventional systems as described above, the absorption and recovery system is complicated and the equipment and operations are complicated. That is, these systems require an absorption tower for nonvolatile petroleum-based organic liquid, a regeneration tower, an absorption liquid circulation pump, and a vacuum pump in addition to the gasoline liquid absorption and recovery system, and have the disadvantage of being redundant. ing.

``Structure of the Invention'' Means for Solving the Problems A mixed gas of air and hydrocarbon vapor is pressurized by a gas compressor, and this pressurized mixed gas is brought into contact with tank storage liquid as an absorption liquid in an absorption tower to carbonize it. The hydrogen vapor is absorbed, and the hydrocarbon vapor in the mixed gas discharged from the absorption tower is permeated and separated by a gas separation membrane and mixed into the inlet mixed gas to the gas compressor, and the hydrocarbon vapor is separated by the gas separation membrane. 1. A method for recovering hydrocarbons from a mixed gas, characterized by dissipating the separated and reduced gas into the atmosphere.

EXAMPLE To further explain the present invention as described above, the present invention can economically convert the above-mentioned mixed gas of air and hydrocarbon vapor into hydrocarbon vapor using relatively simple equipment and original injection using a gas separation membrane. We were able to successfully separate and recover the
The main equipment is a compressor that pressurizes the mixed gas, an absorption tower that recovers hydrocarbon vapor from the pressurized mixed gas, and a further separation and removal of the hydrocarbon vapor in the mixed gas that comes out of the absorption tower. It consists of a gas separation membrane and a vacuum pump.

That is, one example of its specific configuration is as shown in the attached drawing.
A mixed gas 1 of gasoline and air derived from a normal pressure gasoline tank or the like is compressed into a gas compressor 2 at a rate of 2 to 3 kg /
ad G and sent to the absorption tower 3. The absorption tower 3
The mixed gas entering from the bottom of the absorption tower 3 is absorbed by direct contact with the gasoline liquid supplied to the upper part of the absorption tower 3 by the gasoline feed pump 4 while rising inside the tower, and is recovered as gasoline liquid. What is thus absorbed into the gasoline liquid and accumulated at the bottom of the absorption tower 3 is returned to the gasoline tank by the gasoline return pump 5. Although the mixed gas 6 led out from the upper part of the absorption tower 3 still contains gasoline vapor of 1% or more, the mixed gas 6 is sent to the gas separation membrane mechanism 7. For this, a material such as silicone rubber or butadiene-acrylonitrile membrane material, in which hydrocarbon vapor has a higher gas permeation rate than air, is used, and the low pressure side is heated to 150 Torr with a vacuum pump 9.
By applying a certain degree of negative pressure, the gasoline vapor contained in the mixed gas 6 is permeated and sent as a return gas 10 together with the mixed gas 1 to the gas compression a2.

Exhaust gas 8 in which gasoline air is preferentially permeated and the gasoline vapor concentration is at least 5νo1% or less is gas separated 1.
After leaving the desert mechanism 7, it is reduced and dissipated into the atmosphere.

The gas that has passed through the gas separation membrane to the low pressure side as described above is pressurized at the outlet side of the vacuum pump 9 and is compressed by the gas compressor a2.

To explain a specific example of operation, for example, 35 ν0
A mixture gas 1 of 1% gasoline vapor and 65 νO 1% air has a feed rate of about 400 N rrr/Hr.
It is pressurized to 2.5 kg/cfG by the gas compressor 2 together with the return gas 10 of 0 N n (/Hr) and sent to the absorption tower 3, where it is directly contacted with the gasoline liquid supplied by the gasoline feed pump 4 to generate gasoline vapor. It is recovered as a gasoline liquid and returned to the gasoline tank by a return pump 5. A mixed gas 6 containing 10-odd VO 1% gasoline vapor
Gasoline vapor is selectively permeated to the low-pressure side through a separation membrane made of a silicone rubber membrane material, and the mixed gas having a gasoline vapor concentration of around 45 VO 1% is sent from a vacuum pump to the gas compressor 2, and the mixed gas 1 at normal pressure is It was possible to effectively separate and recover more than 85% of the gasoline vapor contained in the fuel.

"Effects of the Invention" According to the present invention as explained above, this type of air and hydrocarbon vapor can be effectively separated and the hydrocarbon vapor can be recovered, and the absorption and recovery system is This invention has the advantages of being simple, extremely simple in terms of equipment, and easy to operate, making it a highly effective invention industrially.

[Brief explanation of the drawing]

The drawings show the technical content of the present invention, and are explanatory diagrams showing an outline of equipment for implementing the method of the present invention. In this drawing, 1 is a mixed gas, 2 is a gas compressor, 3 is an absorption tower, 4 is a gasoline feed pump, 5 is a gasoline return pump, 6 is a mixed gas, 7 is a gas separation membrane mechanism, 8 is an exhaust gas, 9 is a vacuum pump, and 10 is a return gas. Patent applicant: From Nippon Kokan Co., Ltd.
Written by Mamoru Kato
Norio Bengami

Claims (1)

[Claims] 1. A gas mixture of air and hydrocarbon vapor is pressurized by a gas compressor, and this pressurized mixed gas is brought into contact with tank storage liquid as an absorption liquid in an absorption tower to produce hydrocarbon vapor. The hydrocarbon vapor in the mixed gas discharged from the absorption tower is permeated and separated by a gas separation membrane and mixed into the inlet mixed gas to the gas compressor, and the gas separation membrane separates and reduces the hydrocarbon vapor. A method for recovering hydrocarbon vapor from a mixed gas, characterized by dissipating the released gas into the atmosphere. 2. The method for recovering hydrocarbon vapor from a mixed gas as set forth in claim 1, wherein the permeation side of the gas separation membrane is made negative pressure by a vacuum pump to promote permeation of hydrocarbon vapor.