US1595334A - Condensing system - Google Patents

Description

Aug. 10 1926.

E. J. ATCKISON coNDENsING SYSTEM mue@ Nov. 1, i922 4 sheets-sheet 1 QN EN NN.

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Patented Aug. 1o, 1926.

UNITED STATES PATENT oFFlcE.'

EDWARD J. ATCKISON, OF LOS ANGELES, CALIFORNIA, ASSIGNOR TO SOUTEWESTERN CONDENSER COMPANY, OF LOS ANGELES, CALIFORNIA, A CORPORATION OF CALI- FOBNIA.

' CONDENSING: SYSTEM.

Application led November 1, 1922. Serial No. 598,288.

This invention has to do generally with systems, processand apparatus. for fractionally condensing vapors; and the present commercial application of the system,

-i that I shall explain as a typical embodiment of the invention, is to the fractional condensation of hydrocarbon vapors. Although the invention is not necessarily restricted to the refining of petroleums it will be best understood from a detailed and particular description' of its application in that ininitiallyto such a temperature as to take v off ata single operation the vapors of all the cuts intended-to he taken off: and then that body of vapors is fractionally condensed. These two systems may be more The general object or less combined with each other; but however the operations are carried on there are certain difficulties and disadvantages. The second mentioned system has the general advantage over the first that the whole body of vapors is taken off' at a -single distilling operation, and it is generally recognized that, this method of procedure is the more efficient. But in any case, where it is desirable or necessary to fractionate the va'- pors (fractionally condense them) considerable losses have been encountered, especially of the lighter fractions. It has been the general experience that the lighter fractions such as gasoline lag behind in the heavier fractions. In order to recover this gasoline it is necessary to rerun the heavier distillates; and this not only greatly increases the cost of production but also decreases the total avaiable quantity of gasoline present in the system because on each vaporizing run a certain percentage of the lighter fractions is converted into xed gases.

Another difficulty encountered has been4 the maintenance of uniform temperature of condensation for the different fractions. of my invention Aincludes the overcoming of these' difficulties, but there are several other objects'and all o these and the corresponding features ofthe invention from the standpoint of both process and apparatus will be best understood from the following detailed specification, reference being had for these purposes to the accompanying drawings, in which:

Fig.. 1 is a lnore or less diagrammatic elevation showing the layout of a complete condenser plant;

Fig. 2 is an enlargement, partially in section, of parts of the apparatus shown-in Fig. 1;

Fig. 3 is an enlarged horizontal section of one of the condenser units taken as indicated by line 3-3 on Fig. 2;

Fig. 4 is a vertical section on linev 4-4 of Fig. 3; and

Fig. 5 is a `vertical section on line 5-5 of Fig. 3; and trating the valvular arrangement of one of the condenser sections.

For the purpose of explaining the process I will assume that mixed vapors, such as come `off of crude oil atsay approximately 650 to 750o F., enter the apparatus through pipe 10 and come to fractionator unit A at approximately that temperature. Entering this unit they passinto a tower 11 that is filled with broken porous roch, coke, or some other suitable filtering material as indicated at 12. This filtering material is supported on perforated partitions 13; and over the head of inlet plpe 14 there is a deflector 15 that spreads the vapors to substantially uniform distribution. The vapors passing up through this tower then pass through condenser unit 16 and thence to another similar tower 17 that also has a filling of filtering material 12 supported on perforated shelves 13. Thence theI remaining vapors pass by pipe 18 vto the next fractionator unit B which is similar in construction to unitA, except that the units are not necessarily of the same size or capacity. The condensate, which in a typical case is gas oil, passes off from unit A through pipe 19. The condensate from unit ,B, usually #3 distillate, passes off from unit B through pipe 20; and the remaining vapors fromunit B pass by pipe21 to the next unit C; where the condensate :#:2 distillate passes off through pipe 22, and the remaining vapors pass through pipe 23, to the next unit At this unit then the condensate, :#:1 distillate,

Fig. 6 is a diagram illusf passes off through pipe 24 and the remain- 110 ing vapors pass through pipe 25 to the next unit E where the condensate passes off through outlet 26 and the remaining vapors pass through pipe 27 to the final condenser unit F where the final gasoline condensation takes place. Now it will of course be well understood that, due to the condensation of a certain fraction in each one of the units, the temperature of the vapors leaving each unit is lower than the incoming vapor temperature to that particular unit. The amount of temperature lowering in each unit depends upon varying conditions, and upon the temperatures at which it is desired to take offl the successive fractions. As a typical instance I may say that the initial temperature of the vapors passing into unit A may be from 650 to 750 F. Sufiicient cooling takes place in unit A to send the vapors out of that unit to unit B at a temperature of from 500 to 600 F. This means of course that the fraction that condenses at such temperatures (500 to 600 F.) is thrown down in unit A. In unit B the temperature is reduced .to say 450 to 500 F., condensates that condense above those temperatures being thrown down; likewise in unit C the temperature is reduced to say 400 to 450O F.; in unit D to 350 to 400o F. and in unit E to 325 to 350 F. As I have said, these figures are used only by Way of illustration and to have some definite figures on which to base my description of operation; and thus although I have placed the figures indicating these temperatures on the drawings it will be understood that they are `not in any sense a limitation. The final gasoline outlet is at 28 from condenser unit F.

This condenser unit F may utilize both water and oil as a cooling fluid, the cooling water being fed in through pipe 29 and out through pipe 30 and the cooling oil going in through pipe 3l and out through pipe 32 to an automatic thermostat controlled valve 33, controlled by thermostat 34 located at the bottom of upper Vtower 17 of the next fractionator unit E. The function of this valve is to distribute the oil stream between a pipe 35 that leads to condenser unit 16 of unit E, and a by-pass pipe 36 that joins the outlet pipe 37 which leads to the next thermostatic valve 33 of unit D. `All of these thermostaic valves and piping systems are or each of the fractionator unitsthe same and therefore a description of one suffices for all. The thermostatic valve itself needs no particular or detailed description as such valves are standard. After having been once set to maintain a certain temperature, these valves will maintain that temperature of vapors emerging from condenser units 16 by automatic diversion of` the cooling fluid either through or around the condenser unit.

So far as my invention in its broader aspects is concerned it is of no particular consequence just what kind of liquid is used as a cooling fiuid. However, I prefer to use oil as the cooling fluid for condenser unit- 16 and the upper parts ofl condenser unit F because the temperatures in those units are substantially above the boiling point of Wa,- ter; and further because the same oil that is going to be put into the still may be preheated in this manner. I also prefer to utilize water in the lower and cooler parts of condenser unit F to effect final condensation of the hydrocarbons that condense at relatively low temperatures.

Before explaining the peculiar advantageous features of the foregoing described cooling fiuid arrangement and control, I wish to explain somewhat in detail the construction of condenser units 16 and F, so that I may then explain how each of those condenser units is controlled to maintain accurately the desired temperature, regard.

less of the fact that greater or lesser amounts of liquid may be condensed in the various condenser units. These condensers are preferably made up in sections that may be built up in any number to form a condenser unit of any desired size. The details of one section are shown in Figs. 3, 4 and 5. The body of the condenser is a suitable casting with end walls 40 that become, in function, what are ordinarily known as tube sheets; the condenser tubes 41 extendingbetween these two Walls and extending clear through each one of them so that their ends are open to the spaces within covers 42 mounted on the end walls. The side walls of the casting enclose two opposite fluid jackets, each of which is divided into a plurality (in this case 3) of fluid passages 43 divided by Webs 44. At each of two opposite corners of the structure there are l0- cated three-way valves 45, these valves being situated in vertical passages 46 which are open at the top and bottom of the casting so that these passages 46 may be registered with the correspondlng passages of adjacent condenser sections. Valves 45, as will be readily apparent from an inspection of the drawings, and partlcularly Flg. 5 have ports located in such a manner that, by adjustment of a valve, any valve will send out through port 47 into passage 43, a certain amount of the Huid that is fiowlng through vertical passage 46, allowing the remainder of the -fluid to pass on through the vertical passage to the other valves. One series of valves 45 acts as inlet valves, the other series acting as outlet valves; and

by the proper regulation of either or both inlet and outlet valves the amount of coolmanipulation the various divisions of tubes may take their cooling uid in series relationship, or in parallel relationship, or in a combination of the two. This will be made clear after I complete the description of the condenser construction.

Tubes 41 are dividedin each condenser section into divisions corresponding to the divisions of passages 43 (see particularly Fig. 5). At each end of each division of tubes there is a cover 42 enclosing a space outside the tube ends of that division. Each cover 42 may have a guide wall 50 whose function causes the following discribed circulation of the cooling fluid. Suppose that passage 46 shown at the right in Figs and 4 is the intake passage. The `cooling fluid for any one tube division will then pass through the corresponding valve 45 and will flow in the direction indicated by the arrows in Fig. 3 through passage 43 and into the space a in cover 42 and thus into and through those tubes whose ends connect with space a. Thence the cooling fluid passes through those tubes and into the space b of the opposite cover 42 and then into the ends of the other tubes that also communicate with space b. Then the cooling lfluid passes through these tubes and into space C of the first mentioned cover and from this space then passes into the remaining tubes of the division which communicate with space c at one end and at the other end with space d of theV second mentioned cover. The fluid then flows from spa-ce d into-the discharge passage 43 and through valve 45 into the common discharge passage 46. It will thus be seen that the function of walls 50 is to divide each tube division up into smaller tube units and to put the several tube units into series relationship. It is possible of course to useno walls 50 and then ,allfthe tubes of a division will be in parallel relationship and no fluid will pass twice through a tube. On' the other end, by using a larger number of division' walls 50 the coolingfluid may be forced to flow in series through as many tubes as may be desired.

Now if vcooling fluid is introduced into one passage 46 it may be distributed equally or unequally to the several divisions and will emerge from the several tube divisions into the other common passage 46. Such an arrangement puts the different tube divisions in parallel with each other; and it will readily be understoodthat all the tube divisions of a 4condenser unit made up of any number of sections may be thus operated in parallel relation. On the other hand, by proper manipulation of the valves 45 it is possible to put all or any desired number of tube divisions in series relationship. In order to explain this I will refer particularly to diagram of Fig. 6. In this diagram I will sup-h pose a cooling fluid enters' firstthe passage 46 at the right and comes first to the valve ldesignated 45% This valve may be set-in the position indicated so as to throw all of the fluid in the direction indicated by the arrow into the tube division designated 41. and to prevent any fluid from passing on down through passage 46. The cooling fluid from tube division 41a then comes -to the outlet valve designated 45b and this valve is set in a position to pass all the fluid taken through its passage 46 to the next valve 45 that belongs to tube division 41". This valve is set, like valve 45, to pass all the fluid over to tube division 41h, and pass none of the cooling fluid so taken along the passage 46.

. Then the cooling fluid comes from tube division 41b to valve 45d which is set like valve 45b with the result that the cooling fluid then passes down passage 46 to valve 45e which is set again like valve 45 and turns the cooling fluid into tube division 41, whe-nce it flows to valve 41f which is set fluid to the lowermost partof passage 46, either then to flow out of the condenser or to flow into the next connected section. It will now be seen how all the tube divisions may be put in either parallel or series relationship and it will also be apparent, without further discussion, how a combination of these two relationships may be effected. For instance, suppose that in a condenser unit of two or more sections the valves of the uppermost lsection are arranged in the manner indicated in Fig. 5, so that the three tube divisions of that section are in parallel relationship. The cooling fluid in that section will theny flow from one passage 46 through all three tube divisions, in parallel, to the other passage 46. lThen flowing up this second mentioned passage 46 to the valves at that side of the next upper section,-

the cooling fluid will then pass through those valves of the nextnpper section into the three tube divisions of that section those valves being also arranged to put those tube divisions into parallel relationship and deliver the cooling fluid through those three divisions, in parallel, -into the passage 46 at the first mentioned side of that sect-ion.

like valve 45b and delivers the Direct communication between the corre' sponding first mentioned passage 46 of the next upper section may be cut off by proper manipulation of the uppermost valve in that last mentioned passage. ByA such manipulation of the valves it will be seen that the cooling fluid may be caused to take a zigzag course upwardly through the whole 'condenser unit and to vefl'ect any desired combination of parallel and series arrangements. v,

Now the objectv of all this is to obtain individual control of each condenser unit/independently of.- all the other condenser units. It will be seen from-what I have saidbefore amount of cooling fluid may be by-passed around the condenser unit. In the initial setup of any given apparatus the piping arrangement is made of sufficient capacity to pass enough cooling fluid to take up the v total quantity of heat given off in the entire system; and also sulcient to take up, in any one unit, within the temperature limits of that unit, all the heat given ofi1 by reason of vapor condensation in that unit. This being the case, it is readily seen that the amount of cooling fluid is greater than is necessary for those units in which less condensate is thrown down and less heat is given off. In fact, the amount of cooling fluid is necessarily such that if the whole of it were to be put through one of those condenser units that condenses a smaller amount of liquid and gives off a smaller amount of heat, the temperature in that unit would be lowered way beyond the desired temperature and the vapors would consequently not be properly fractionated. It will thus be readily seen how the by-passing, under automatic control gives entirely independent control over the amount of cooling fluid passing through each individual condenser unit and thus gives individual and accurate control of the temperature at Aeach condenser unit. Furthermore, the capability of each condenser unit being arranged to pass the cooling fluid in either series or parallel relationship, or in a combination of those two relationships, enables me accurately to control temperatures of the .individual condenser units. For instance, 1n those units where it is necessary to tpass a comparatively large amount of cooling fluidz the tubes may be arranged in parallel relationship, or in a suitable parallel series relationship in order to pass the desired amount of cooling fluid in any unit of time. In other units where there is not so much heat to be taken off and therefore'it will'not be necessary to pass so much cooling fluid,

the arrangement may be to put the tubes into parallel series or series relationship.

`Whatever amount of fluid is being passed through any of the units, it is desirable to arrange the`tube relationships in such a manner that the cooling fluid passage is of not too small total cross-sectional area, so that reasonable pressure will suffice to overcome the friction. .On the other hand, it is desirable to obtain series relationship as far as is consistent with free flow of the necessary quantity of cooling fluid, because then the cooling fluid will pass successively into lowerand hotter parts of the condenser units (I may now speak particularly of condenser unit 16) and the distribution of temperatures and of heat exchange will be more uniform from bottom to top of the condenser unit than would be the case if all the tubes were in simple parallel relationship.` Fur- .used for this purpose.

thermore, by adapting the series or parallel or combined relationships to the quantity of cooling fluid necessary to be passed through any given condenser unit, the fluid movement through the passages and tubes may be kept at a reasonable velocity, prevented from becoming sluggish, and thereby greater uniformity of distribution of the cooling fluid to the various individual tubes may be maintained.

For facilitating cooling fluid connections to the condensers, provision is made for pipe connections into the sides of the units at various points. 0f course it will be readily understood how the cooling fluid connections can be made with the upper and lower ends of vertical passages 46; pipes 29 and 32 are shown so connecting to condenser F in Fig. l. But Where it is desired to feed different fluids to separate parts of the condenser, or where it may be diiicult to make Connections at the ends of passages 36, the valves 45 are provided with pipe receiving arrangements. Each valve is, in form, a

hollow or shell plug 45 with its outer end closed by removable screw threaded plug 451. By removing selected plugs 45p, pipes may be connected into the valve shells 45. Such connections are shown with pipes 35 in Figs. 1 and 2. Or pipes, as shown at 30, 31 and 37 in Figs. 1 and 2 can be connected directly into condenser passages 46 through the walls of those passages at any point. Figs. 4 and 5 show a hole 46h that may be Such provisions facilitate the supply of different cooling fluids to separate parts of a single condenser, as shown for condenser F in Fig. 1. And it will be well understood how a valve or valves 45 may be manipulated to close off that part of passage 46 which is below any point of pipe connection from that part that is above said point. For instance, valve 45h in Fig. 6 is shown in such a position that it cuts off passage 46 above it from passage 46 below it.

Thus, the capability 'of my condenser conl struction to effect` this tube relat1onsh1p plays a part in the maintenance of umform 4and accurate temperatures 1n the various one of the fractionator units, as typical of `the action in all the fractionator units. For

this` purpose I refer particularly to Fig. 2 which shows units B and C. I have described how the vapors enter the lowerk lower tower 11, coming tower 11 and pass up through the filtering material it contains into condenser unit 16. In these condenser units uniform tempera- .tures are maintained; for instance, in unit B the uniform condenser temperature may be say 500 F. and, in the condenser of unit C the temperaturev may vapors passing up' through the condenser ofl unit B are reduced to 500 F. and the condensate down to 500 F. falls back throu h into contact with t e vapors in that tower which are fed in at say 600 F. or somwhat less (if the temperature maintained in the condenser of unit A is 600 F., of course the vapors will not reach lower tower 11 of unit B at Iquite that temperature; but for the purposes of this description the small loss of temperature may be ignored). Due to the cooler condensat-e falling down through tower 11, the average temperature maintained there will be somewhat less than 600 F. but will be more than the temperature of 500 F. maintained in the condenser unit; and this increased temperature to which the falling condensate is subjected causes the revapori- .zation of all or substantially all the lightery .condensates that have been carried down by and with the heavier condensates that properly condense in this particular unit. It is well known that in any condensin operation at any fixed temperature, in addition to the fluids that theoretically condense at that xed temperature, there will always be found in the condensate al certain percentage of iiuids that theoretically condense at a lower temperature but are carried down by the heavier condensates. In my system these lighter portions of the condensate are revaporized by contact with the hotter vapors; and iltration through 'the filtering material in towerll not only helps to free'these revaporized vapors but also helps to free any vapors of lighter constituents that have beenl down in vapor form along with the carried The vapors of all -vthese lighter condensate.

' constituents, that theoretically do not condense at the temperature of the condenser, then pass on through the condenser and into u pper tower B.' yHere again the vapors and liqulds are separated from each other, an remaining condensates that are carrie physically by the vapors being more or less completely separated out; so that the vapors that then-pass from unit B through pipe 21 to unit C aresubstantially dry. l

y The safrne kind of action takes place in each' one of the fractionator units; with .the sum total result that very little of the gasoline content is le'ft behind-lags-in the various heavier fractions. In fact, my system cuts down very'materially the amount of gasoline left in the heavier fractions as compared with other prosesses now in combe 400 F. The

vI obtain what is known as gasoline to make it worth amount of gasoline.

inv series, vextending' around each condenser umt, a

mercial use; and therefore it eliminates the necessity of rerunning those heavier fractions for the purpose of obtaining whatever gasoline or other lighter fractions they contain. Furthermore, because in my system the vapors are thoroughly filtered at each unit, very little heavier fractions are carried over into any lighter fractions; Thus strai ht-run gasoline, with very little gasoline oss.

It is necessary, of course, to cool the condensates from the fractionator units to approximately atmospheric temperature, before putting into storage tanks. The condensate coming from the last fractionator unit E may in some instancesA contain enough while to re-run; but this is the only condensate that under any circumstances contains any substantial Having described a preferred form` of my invention, I claim:

1. Apparatus for fractionally condensing mixed vapors, comprising a lurality of condenser units, the vapor ta e-off from one unit being connected to the vapor feed of the next unit, each unit embodying a plurality of cooling tube divisions and means whereby said divisions may be connected in series or in multiple, and a common'cooling fluid system to put cooling fluid through the several units in series.

2. Apparatus for fractionally condensing mixed vapors, comprising a denser units, the vapor take-off from one unit being connected to the vapor feed of the next unit, veach unit embodying a plurality of cooling tube divisions and means whereby-said divisions maybe connected in series or in multiple, a common cooling fluid system to put cooling Huid through the several units 1n series, tuated means controlled by the vapor-temperature at the take-olf from each condenser unit to regulate supply of coolingtluid to that unit. l

' 3. Apparatus for fractionally condensing mixed vapors, comprising a plurality of condenser units, the vapor. 'take-off from each unit being connected to the vapor feed of the next, a common coolin fluid system to put cooling fluid through t e several condensers a by-pass in said cooling system fvalve controlling distribution of fluid throu h each unit and its respective by-pass,

plurality of conand thermostatically acand t ermostaticf means controlled by the temperature of vapors at unit' to actuate said valve.

In' witness that I claim the fore have hereunto subscribed my name t day of *October 1922.

oing I 's 14th the take-off of each A

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