US1740281A - Refrigerating system - Google Patents

Description

Dec. 17, 1929. Si, Q CARNEY 1,740,281

REFRIGERATING SYSTEM Filed Aug. 2l.- 1925 Patented NDec. 17, 1929 UNITED STATES PATENT OFFICE' SAMUEL C. CAREY, 0F TULSA, OKLAHOMA, ASSIGNOB T0 SHELL PETROLEUM COB PORATIONNA. CORPORATION 0F VIRGINIA REFBIGERATING SYSTEM Application filed August 21, 1925. Serial Nc. 51,559.

This invention relates to improvements 1n refrigerating systems.

An object of the invention is to provide a continuous processvwhcreby a hydrocarbon mixture is segregated to form a componentl having a low boiling point that will evaporate at a temperature sufficiently low so that it may be successfully used commercially `as a refrigerant; then passing the refrigerant through a refrigerating apparatus, and then recovering the expanded refrigerant and returning it to the system in a form in which it may be utilized repeatedly as the cooling agent.

.Particularly the present invention is concerned With a suitable recovery process Whereby the expanded refrigerant is absorbed in a cooled hydrocarbon liquid, for instance a petroleum oil, with provision for redistilling the absorbing liquid so as to drive O' and segregate therefrom the absorbed component so that the same may be used as the charging element ot the refrigeratinl apparatus.

Additional advantages oli the process will readily appear from the following detailed description thereof, taken in connection with the accompanying` drawing in Which the single iigure of the drawing illustrates a suitable form of apparatus for practicing the process.

ln the drawing 1 represents a rectii'ying column which is in the form of a cylindrical container having a series of rectilying plates therein. A hydrocarbon mixture of a characactor, that, by treatment under coordinated temperatures and pressures according to known practice, can be segregated into a liquid com onent and a vaporous component is utilized or charging the rectifying column.

'lhis hydrocarbon mixture is introduced into' the rectifying column through a supply pipe 2. The liquid in the bottom part of the rectitying column 1 is heated by any suitable means such, for instance, as by a heater 3 having a heating coil 4, a steam inlet pipe 5,

` and a steam return pipe 6, it being understood that the Well 7 of the rectifying column communicated with the heater by pipe connections 8 and 9. By balancing the temperature and the pressure Within the rectifying column the ydrocarbon mixture is segregated into a liquid component that accumulates in the lower part of the rectifying column from which it 1s Withdrawn through a pipe 10. The lighter volatile-component of the mixture is driven ofi" as a vapor from the top of the rectitying column through the pipes 11 and 12 'which communicate with a condenser 13. rl`he condenser 13 is cooled by any suitable means such, for instance, as Water coils, thereby reducing the temperature of 'the vapor passing therethrough to a degree sutilcient to liquety a portion thereof.

lt Will be understood that the hydrocarbon mixture that is introduced into the rectifying column comprises preferably a gasoline component and lighter fractions and that the l gasoline component is drawn oil as la liquid through the pipe 10 and conducted to storage. 'llhe lighter fractions vaporize and are drawn oit from the top of the column and arethen condensed and used as a. retrigerating agent.

A container 14 is located belovv the condenser 13 and is connected therewith by a pipe 15. A portion oi? the liquid component accumulated in the container 14 returns to the rectitying column through a U-shaped piping comprising the pipes 16, 17 and 18. A nozzle 19 is connected With'the upper end oitI the pipe 18 and discharges into the upper part of the rectitying column.

The vaporous component resulting from the treatment in the condenser 13 is Withdrawn from the upper part ot the container .Il loyv a pipe 20, by means of which it is conducted to.a refrigerator 21.

A. portion of the condensate from the container 14 is Withdrawn through a pipe 22 connected with the pipe 16, by means otivhich valve 27 may vator 21 may be automatically ermostatic ele- Thefi'ow of a thermostatic valve 28, the t 'ment 29 of which is in the takeod line 23.

Thus, as determined by the temperature ofthe liquid discharge from the refrigerator 21, a greater or lesser quantity of the refrigerating liquid from the pipe 22 may be admitted to the expansion coils of the refrigerator 21 as may be required to edect condensation of the vapor admitted theretothrough the pipe 20. For convenience of illustration one practical use of the .refrigerator 21 has been shown Velement in refrigerating boxes,

- the carrying agent the inconnection with the general system. lt will be understood, however, that the function of the refrigerator as means for condensing a hydrocarbon vapor is only referred toas an example of its use, and that the refrigerator may also be utilized for cooling liquids from an independent source such, for instance, as circulating coils for brine tanks, or may be utilized as an independent cooling and for other purposes. y l

The present invention has todo particularly with .the expansion and recovery of a suitable refrigerating agent conveniently provided according to the above description,

l but the refrigeratingl agent may be derived from other sources such, for instance, as from containers in which the refrigerant, in the form of a condensate, may be directly connected with the pipe 22.

The problem of recovery of theI expanded refrigerant involves the provision of suitable means for taking up oriabsorbing the expanded refrigerant after it has functioned in the expanding coils of the refrigerator 21, together with the means for distilling from absorbed vapor resulting from the expansion of the liquid inthe c xpansion coils so that the vaporous component may be readily separated and returned to the system for use.

From the refrigerator 21 the vapor, after expansion in the expansion coils, is withdrawn through the pipe 30 and conducted to an absorber 31. The absorber 31 preferably comprises a steel cylinder having an extended internal surface and contains an absorbing liquid. The absorbing liquid utilized is preferably a relatively heavy Vpetroleum oil having a relatively low vapor pressure at its absorbing temperature. ItisV desirable that the liquid absorbent have a low viscosity, low molecular weight, preferably 80 ito 225, and that it be cooled to a'relatively low temperature ranging between 0 F. to 70 F.,

ow ofthe vapor in order that the amount of refrigerant which it will dissolve will be as great as possible.

ln order to maintain the relatively low temperature of the absorbent liquid within' the absorber 31 the absorber 31 is provided with internal means for cooling the liquid such, for instance, 'as water coils 32 having external connections 33 and 34.

ln the operation be accumulated within the absorber a relatively small quantity of insoluble gases that are not taken up by the liquid. rlhese gases accumulatein the upper part of the absorber 31 and, in order to purge the absorber of these accumulated gases, an outwardly opening relief valve 35 is provided.

By coordinating the temperature and pressure of the absorbent liquid, within the absorber 31 a condition is produced under which the vapor entering the absorber from the pipe 30 is substantially completely absorbed in the carrying liquid. The liquid carrying the absorber vapor is withdrawn from'a low point in the absorber and by meansof a pump 36 through a pipe 37 t0 a heat exchanger 38, and thence by means of a pipe 39 into the upper part of a still 40, the pipe 39 discharging into the still through an internal ynozzle-41. The still 40 is preferably in the form of a cylindrical shell and may be provided with rectifying plates to effect a segregation of the vaporous component dissolved in the absorbent liquid, so that the vaporous component nmay returned to the system.

The still 40 is internally heated by any suitable means such, for instance, as by a steam coil 42 having steam inlet and return passages 43 and 44, respectively, the passage 44 discharging through a steam trap 45. The still 40 is in edect a rectifying column for accomplishing the segregation of the absorbed 4 vapor from the carrying liquid, the ,degree of segregation being predetermined by the balancing of pressures and temperatures within the still. The vapor driven oiflfrom the still 40 colnprises the fraction substantially corresponding to themixture originally utilized in a condensed state as the refrigerant for the refrigerator 21 and, c 'n the embodiment shown, is returned to the system through a pipe 46 connectedinto the pipes 11 and 12. The vapor then passes through the condenser 13 and then to the container 14 from which it is withdrawn for use in the expansion coils of 'the refrigerating apparatus.

4The accumulation in the bottom of the still is the heavier liquid used as the absorbent or carrying liquid, and this is withdrawn from a low point of the still through a pipe 47 connected into the heat exchanger 38 in which it is initially cooled by the effect of a liquid of a lower temperature iowing through the heat exchanger 38 from the pipe 37. From the heat exchanger the liquid is subjected to of the system there may i forced, under pressure, y

bedriven oft' and Y i coils of a secondary cooling treatment in a cooler 48 to which it is conducted by a pipe 49 leading from the heat exchanger 38. The cooler 48 is cooled in any suitable manner such, for instance, as by Water coils. The liquid, after having been subjected to the coolin treatment 1n the cooler 48, is reintroduced lnto the absorber 3l near the upper part thereof through a pipe 50 equipped with a. nozzle 51 internally disposed in the absorber 31.

What I claim and desire to secure by Letters Patent is 1. In a refrigerating process the step of reclaiming an expandedhydrocarbon refrigerant, which consist in subjecting a Vapor of the refrigerant to the absorbent action of a liquid hydrocarbon capable of effecting substantially complete absorption of the vapor; and then redistilling the liquid containing the vapor to segregate the absorbed vapor from the liquid.

2. In a refrigerating process the ste of reclaiming an expanded hydrocarbon re rigerant, Which consists in commingling the vapor With a hydrocarbon liquid under the influence of pressure and reduced temperatures to effect an absorption of the vapor by the liquid and then re'distilling the mixture under the influence of heat and pressure to effect a segregation of the liquid from the vapor.

3. The process of evacuating expansion a refrigerator charged with a hydrocarbon refrigerant, which consists in dissolving the vapor of the refrigerant in a hydrocarbon liquid under balanced temperatures and pressures; conducting the saturated liquid to a remote point for treatment; raising the temperature of the liquid to redistil the same to segregate the vaporous component from the liquld component; then withdrawing the liquid component through a heat exchanger cooled by the saturated liquid, and returning the same to the original point of treatment. v

4.. rlhe process yfor reclaiming an expanded hydrocarbon refrigerant, Which consists in subjecting the expanded vapor to cooling and pressure in the presence of a. hydrocarbon liquid capable of dissolving the vapor in an absorber; conducting the resultant liquid under pressure to a still and through a heat exchanger; raising the temperature of the liquid to drive oli' the vaporous component; returning the liquid component through the heat exchanger to a cooler, and then returning the liquid to the absorber.

5. ln a refrigerating process that step for evacuating the refrigerating coils, which consists in commingling the vapor from the. coils with a hydrocarbon liquid capable of effecting substantially complete absorption of the vapor.

6. In a refrigerating process the stepy of ,evacuating refrigcrating coils charged with relatively light fractions Which consists in lntroducing said vapor into a relatively heavy petroleum oil of low molecular weight and at a temperature and pressure to produce a condition under Which the vapor is substantially completely absorbed.

SAMUEL C. CARNEY.

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