SU1465674A1 - Cryogenic reservoir - Google Patents

Abstract

The invention relates to a cryogenic technique and allows to increase the economy by reducing the evaporation of the cryoproduct. The reserve contains an adsorption pump (AH) with peripheral and central heat-conducting fins (P), a gas-permeable screen and a heater. The equidistant screen is fitted with a heat shield, the outer surface of which is thermally insulated, while the internal surface is polished. The heater is made of sections, one of which is placed on the outer surface of peripheral P along the entire contour of the Academy of Sciences, and the other on the surface of the central R. The distance 1 between the peripheral and central P is determined by the ratio of 1 d / badd / UHl, where Kg, is the thermal conductivity screen material; BE - the thickness of the screen; bd is the thickness of the adsorbent layer; LA - thermal conductivity of the material of the adsorbent. This leads to the fact that 95% of the heat flux reaching the AN through the thermal insulation layer is removed along P and the layers of adsorbent in contact with the surfaces P, the screen and the vessel are intensively cooled. 2 3. p. F-ly, 3 ill. five

Description

one

The invention relates to cryogenic engineering, in particular, to designs of cryogenic tanks intended for the storage, transportation and distribution of cryogenic products to the consumer.

The aim of the invention is to increase the economics by reducing the evaporation of the cryoproduct due to heat gains from the outside.

FIG. 1 schematically presents the proposed cryogenic tank; in fig. 2 shows section A-A in FIG. one; in fig. 3 shows a section BB in FIG. 2

The cryogenic tank contains an outer casing 1 and an internal vessel 3, which is formed therein to form a heat-insulating cavity 2, on the outer surface of which there is an adsorbent pump 5 filled with adsorbent 4, equipped with peripheral heat-conducting rails 6 connected to them by a gas-permeable screen 7 and a heater 8. The tank additionally contains a protective visor 9 fixed with thermal contact on the ribs 6 equidistant to the screen 7, and nozzles 10, communicating the space between the screen 7 and the visor 9 with the thermal insulation 2, and the adsorption pump 5 is provided with central heat-conducting fins 11. A part of the heater 8 is placed on the outer surface of the peripheral fins 6 along the entire contour of the adsorption pump 5, and some - on the surface of the central ribs 11. Both parts of the heater 8 are fixed with thermal contact on the edges 6 and 11 and the outer surface of the inner vessel 3. The outer surface of the protective visor 9 is provided with a layer of thermal insulation 12, and its inner surface is polished. The distance between the peripheral ribs 6 and the central ribs 11 is selected from the condition

I l

 -1ZHG

four:

O5

sd

05

;

where 1 is the distance between the ribs;

Le thermal conductivity of the material of the screen 7;

XA - thermal conductivity of the adsorbent 4; bd - screen thickness 7; bd - the thickness of the layer of adsorbent 4. The cryogenic tank works as follows.

The inner vessel 3 is filled with a cryogenic product and the walls of the vessel 3 acquire a temperature corresponding to the temperature of the cryoproduct. Due to the good thermal conductivity of the materials of the peripheral and central ribs b and 11 and the gas-permeable screen 7, they are cooled rather quickly to the temperature of the cryoproduct. At the same time, the adsorbent 4 is cooled, which is located in the isothermal cavity formed by the fins 6 and 11, the screen 7 and the wall of the vessel 3. At the same time, the layers of the adsorbent 4 contacting the surfaces of the fins 6 and 11 of the screen 7 and the vessel 3 are cooled more intensively than the inner layers and immediately begin to work on the adsorption of gases in the heat-insulating cavity 2 of the reservoir. These gases from the cavity 2 through the nozzles 10, the size of which is determined by the condition of ensuring the necessary speed of pumping out the heat-insulating cavity 2, enter the cavity formed by the screen 7 and the protective visor 9, and from there through the gas-permeable screen 7 to the adsorbent 4. Heat radiation with the sides of the outer casing 1 do not penetrate into the cavity between the screen 7 and the visor 9, and also does not affect the temperature of the visor 9 cooled with the help of fins 6 and covered with a layer 12 of thermal insulation. Polishing the inner surface of the visor 9 contributes to the elimination of heat inflows from the visor 9, which has a temperature slightly higher than the temperature of screen 7. The fulfillment of the condition for choosing the distance between the fins 6 and 11 leads to the fact that 95% of the heat flux reaching the adsorption pump 6 through the thermal layer insulation is removed along the edges 6 and 11, and not through the layer of adsorbent 4. This ensures that the conditions of operation of the adsorbent 4, which practically do not affect the adsorption characteristics from the point of view of maximum use The potential of the adsorbent.

During tank operation, the adsorbent maintains the required pressure in the heat-insulating cavity.

When the adsorbent 4 is regenerated, the crying product from the tank is drained and the heating of the pump 5 is carried out using a heater 8 (electric or made in the form of a coil for supplying heating gas).

The proposed arrangement of parts of the heater 8 provides heating of the adsorbent 4 by heat exchange with the surfaces of the fins 6 and 11, the vessel 3 and the screen 7, i.e. under conditions similar to the cooling conditions during operation. This fact is positive, since the layers of the adsorbent 4, which come to work primarily during cooling, are heated most intensively and are accordingly more efficiently regenerated.

In addition, this placement of the heater 8 makes it possible to achieve one more centrifuge, the spruce — processability, which consists in emptying the internal cavity of the pump, where the adsorbent is placed from the heating device. In the known tank designs, the heater takes up part of the volume of the adsorption pump, making it difficult for the adsorbent to backfill when mounting the tank. In this case, the pump is free; backfilling of the adsorbent was not - 0 em labor.

Improving the process of regeneration of the adsorbent makes it possible to increase the resource of its work and, in general, to increase the working cycle of the tank between the regenerations of the adsorbent. As a result, for the full period of operation of the reservoir, the drain of the cryoproduct for regeneration is more rare; it leads to a reduction in the loss of the cryoproduct for evaporation during subsequent filling of the "warm reservoir." In addition, 30 increasing the adsorption characteristics of the adsorbent due to the good regeneration, as well as organizing the supply of gas to the adsorbent without additional heat leakage to it, allows maintaining a higher 35 vacuum in the heat insulating cavity and thereby reducing the evaporation of the cryoproduct during the tank operation.

The proposed calculation formula for determining the distance between the fins is obtained on the basis of considering the balance of heat fluxes discharged by the cooled wall of the tank through the screen, the fins and the layer of adsorbent.

When the calculated limit is exceeded, the specific capacity of the adsorbent drops sharply, and therefore an increase in the distance between the ribs of more than the calculated value leads to a sharp decrease in the specific capacity of the adsorbent and, accordingly, to an increase in the residual pressure in the heat-insulating cavity, which directly affects 50 na. inflows to the inner vessel, growth of these inflows and increase in evaporation of the cryoproduct, i.e., to its loss. Thus, providing the necessary distance between the fins in conjunction with the construction the main features of the proposed reservoir, the main objective of the invention is achieved - the efficiency is increased due to the reduction of the loss of the cryoproduct.

Claims (3)

1. A cryogenic tank containing an outer casing, an inner vessel with a heat-insulating cavity between them, and a cryogenic pump placed on the outer surface of the inner vessel, having peripheral heat-conducting fins, a gas-permeable screen and a heater, characterized in that, in order to increase efficiency by reducing evaporability of the cryogenic product, it is equipped with a heat shield installed outside the gas-permeable screen equidistant to it and having thermal contact with the inner vessel, branch pipes, I report the space between the visor and the heat insulating cavity screen, the adsorption pump is equipped with central heat-conducting fins and the heater sections have a heat , contact with the inner vessel, the outer surface of the peripheral ribs and the surface of the central ribs. 2. The vessel according to claim 1, wherein the outer surface of the visor is thermally insulated, while the internal surface is polished. 3. A reservoir according to claim 1, characterized in that the distance between the peripheral and central edges is determined from the inequality , MA QK where 1 is the distance between the ribs; I, e - thermal conductivity of the screen material; bz - screen thickness; 5d - the thickness of the layer of adsorbent; AL is the thermal conductivity of the ad-sopbent material. ± (eo.2 6-b Sri.H