RU2571754C2 - Method of sorbent regeneration - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: claimed method of sorbet regeneration, in which sorbent is placed in vessel, heated by SHF radiation to separate sorbate from sorbent, blowing gas is passed through vessel to remove sorbate vapours. Sorbent is placed in vessel in such a way, that concentration of sorbate in sorbent increases from lower layer of sorbent to upper layer, and SHF radiation is directed towards the side of sorbate concentration increase. Walls of vessel from outside are blown on by waste blowing gas, output from vessel.

EFFECT: increase of process productivity.

3 cl

Description

The present invention relates to a technology for the regeneration of sorbents - substances that can absorb and retain unwanted moisture (sorbates). The invention can be used in any industry where sorbents are used, for example, in the technology of drying natural gas.

A known method for the regeneration of sorbents according to the invention patent No. 2438774, in which the sorbent is placed in a chamber where it is exposed to microwave radiation. Closest to the proposed invention is a unit for adsorption drying of gas according to the patent of the Russian Federation for utility model No. 134441 - prototype. The specified device contains two vertically mounted cylinders filled with sorbent. A microwave source, a magnetron, is attached to the upper base of each cylinder. For drying, the gas is first passed through a sorbent in the first cylinder. After saturation with moisture of the sorbent in the first cylinder, the gas flow for drying is switched to the second cylinder. At this time, the wet sorbent in the first cylinder is regenerated by exposure to microwave radiation, directed from top to bottom. The radiation is absorbed by moisture, which evaporates. To remove vapors, dry air is blown through the sorbent, which is fed through the lower base. Air presses steam through the pipe at the upper base into the surrounding atmosphere.

The disadvantages of the prototype include inefficiency and lack of environmental protection, since hot steam, possibly with undesirable impurities, is released directly into the atmosphere. In addition, this technology is not effective enough, since when directed from top to bottom, microwave radiation is almost completely absorbed in the upper, wetter layers of the sorbent, which increases the time required to regenerate the entire filling of the sorbent.

The technical task is to increase the efficiency, efficiency, environmental protection of the method of regeneration of the sorbent.

The technical result is achieved by the fact that in the sorbent regeneration method, in which the sorbent is placed in a container equipped with a magnetron, it is exposed to microwave radiation from a magnetron to separate the sorbate, purge gas is passed through the sorbent to remove sorbate vapor, the sorbent is placed in a double-walled container, in an inter-wall the space of which is located a recuperative heat exchanger, and the sorbent is placed in layers in the inner vessel of the tank so that the concentration of the sorbate in the sorbent increases from the bottom to the top layer, microwave radiation is directed towards increasing the concentration of the sorbate, while the exhaust purge gas from the inner vessel of the tank is passed through the space between the walls of the inner vessel and the regenerative heat exchanger, sent to the condenser to cool the exhaust purge gas to the dew point established for condensation sorbate vapor, said gas is passed through a recuperative heat exchanger, and then sent to the inner vessel of the tank.

In the proposed method, the temperature of the sorbent is measured by two sensors located at the ends of the inner vessel, while the microwave radiation power is regulated according to the law of inverse dependence on the difference in the readings of the sensors. In the method, the condensate of the sorbate formed in the condenser is taken to a collection tank for further disposal.

In a specific example, the proposed method is used in an installation for the regeneration of zeolite - a sorbent that is used to dry natural gas. It is proved that when pumping natural gas for drying through a container with zeolite, the moisture concentration in the container increases unevenly. Its value is greater at the inlet pipe of the container with zeolite and less at the output pipe.

Zeolite regenerate (restore) in the following order. The wet zeolite container is rotated so that the layer with the highest moisture concentration is at the top. At the container, unscrew the lid below and pour the zeolite into the inner vessel of the double-walled container. The lid of the vessel is closed. Then include a magnetron integrated in the bottom of the vessel. The bottom is connected by a pipe to a purge gas source. In the process of regeneration, the zeolite is exposed to microwave radiation from a magnetron. The radiation is directed from the bottom up - from the zeolite layer with the lowest humidity to the layer with the highest humidity. Experiments have shown that the absorption of microwave radiation is directly proportional to the moisture concentration in the zeolite. Thus, with decreasing distance from the magnetron, microwave radiation is uniformly absorbed by a zeolite column due to an increase in humidity with height. In this case, moisture evaporates from all layers of the zeolite at approximately the same rate (increased efficiency).

The purge gas blows moisture vapor from the inner vessel through a nozzle in the lid, which is connected to the interwall space of the double-walled container. Here, a hot mixture of gas and water vapor blows around the regenerative heat exchanger (hereinafter referred to as the heat exchanger), as well as the walls of the inner vessel, heating them to prevent undesired condensation of the vapor inside the vessel. Further, the gas mixture that has transferred part of the heat to the heat exchanger is sent to the condenser, where it is cooled to the dew point. In the condenser, water vapor condenses into water droplets that drain to the bottom and are discharged to a steam trap (increasing environmental protection). The dried purge gas is then passed through a heat exchanger for heating. Thus, the heat expended on the evaporation of moisture in the inner vessel is recovered (increased efficiency). The heated gas is sent again to the inner vessel to purge the zeolite.

For optimal control of the magnetron, temperature sensor signals are used that are installed on the bottom and on the lid of the inner vessel. If the difference in the readings of the sensors is large enough, the regeneration of the zeolite proceeds normally. If the readings of the sensors begin to converge, the radiation power is increased to ensure the optimal regeneration rate of all zeolite layers.

According to the described scheme, the applicant’s enterprise tested the method of sorbent regeneration proposed for patenting. Tests showed a good result. So, during a pilot check in a zeolite column with a diameter of 130 mm with a residual moisture content of 15% (mass.) With a magnetron power of 1000 W and a purge gas flow rate of 15 m ³ / h, the desorption rate was up to 10 cm / h, which is at least 20% higher than the speed achieved in known methods.

Perhaps the application of the proposed method to remove another sorbate. For this, the microwave frequency characteristic of this sorbate should be used. For water, this frequency is 2.45 GHz. The characteristic frequencies for other sorbates are published in the literature.

Literature

1. Netushil A.V. et al. High-frequency heating of dielectrics and semiconductors. - M.: Gosenergoizdat, 1959.

2. Puschner G. Heating with microwave energy. - M.: Energy, 1968.

Claims (3)

1. The method of regeneration of a sorbent saturated with a sorbate, in which the sorbent is placed in a container equipped with a magnetron, exposed to microwave radiation to evaporate the sorbate, purge gas is passed through the sorbent to remove sorbate vapor, characterized in that the sorbent is placed in a double-walled container, in a walled the space of which a recuperative heat exchanger is located, and the sorbent is placed in layers in the inner vessel of the tank so that the concentration of the sorbate in the sorbent increases from the lower layer to the upper layer, microwave radiation is directed in the direction of increasing the concentration of the sorbate, while the exhaust purge gas from the inner vessel of the tank is passed through the space between the walls of the inner vessel and the regenerative heat exchanger, sent to the condenser to cool the spent purge gas to the dew point established for condensation of the sorbate vapor, then gas is passed through a recuperative heat exchanger, and then sent to the inner vessel of the tank. 2. The method according to p. 1, characterized in that the temperature of the sorbent is measured by two sensors located at the ends of the inner vessel, while the microwave radiation power is regulated according to the law of inverse dependence on the difference in the readings of the sensors. 3. The method according to p. 1, characterized in that the condensate of the sorbate formed in the condenser is diverted to a collection tank for further disposal.