CA1211677A - Pressure reduction apparatus for solid particle- containing high pressure liquids - Google Patents
Pressure reduction apparatus for solid particle- containing high pressure liquidsInfo
- Publication number
- CA1211677A CA1211677A CA000432989A CA432989A CA1211677A CA 1211677 A CA1211677 A CA 1211677A CA 000432989 A CA000432989 A CA 000432989A CA 432989 A CA432989 A CA 432989A CA 1211677 A CA1211677 A CA 1211677A
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- Canada
- Prior art keywords
- pressure
- gas
- liquid
- tower
- pressure reduction
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J3/00—Processes of utilising sub-atmospheric or super-atmospheric pressure to effect chemical or physical change of matter; Apparatus therefor
- B01J3/02—Feed or outlet devices therefor
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Physical Or Chemical Processes And Apparatus (AREA)
- Control Of Non-Electrical Variables (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A pressure reduction apparatus for solid particle-containing high pressure liquids is described. The apparatus comprises a gas and liquid pressure reduction tower having a gas phase zone and a liquid phase zone, a high pressure gas and liquid separation tower which has a gas phase zone connected to the gas phase zone of said gas and liquid pressure reduction tower through a first line provided with a high pressure gas charge or discharge valve, and a liquid phase zone connected to the liquid phase zone of said gas and liquid pressure reduction tower through a second line having a feed valve for liquid being reduced, and a low pressure gas and liquid separation tower which has a gas phase zone connected to the gas phase zone through a third line having a low pressure gas charge or discharge valve, and a liquid phase zone connected to the liquid phase zone through a fourth line having a valve through which a pressure reduced liquid is discharged. Prior to opening of the feed valve or the pressure-reduced liquid discharge valve, the high pressure gas charge or discharge valve, or the low pressure gas charge or discharge valve is opened thereby increasing or decreasing the pressure within a corresponding gas and liquid separation tower.
A pressure reduction apparatus for solid particle-containing high pressure liquids is described. The apparatus comprises a gas and liquid pressure reduction tower having a gas phase zone and a liquid phase zone, a high pressure gas and liquid separation tower which has a gas phase zone connected to the gas phase zone of said gas and liquid pressure reduction tower through a first line provided with a high pressure gas charge or discharge valve, and a liquid phase zone connected to the liquid phase zone of said gas and liquid pressure reduction tower through a second line having a feed valve for liquid being reduced, and a low pressure gas and liquid separation tower which has a gas phase zone connected to the gas phase zone through a third line having a low pressure gas charge or discharge valve, and a liquid phase zone connected to the liquid phase zone through a fourth line having a valve through which a pressure reduced liquid is discharged. Prior to opening of the feed valve or the pressure-reduced liquid discharge valve, the high pressure gas charge or discharge valve, or the low pressure gas charge or discharge valve is opened thereby increasing or decreasing the pressure within a corresponding gas and liquid separation tower.
Description
TITLE OF THE INVENTION
PRESSURE REDUCTION APPARATUS FOR SOLID
PARTICLE-CONTAINING HIGH PRESSURE LIQUIDS
. Field of the Invention This invention relates to a pressure reduction : ,.
apparatus for solid particle-contàining hi~h pres~ure liquids and more particularly, to a Pre~sure reduction apparatus for use in chemical plants which deal with high ;~ pressure liquids comprising solid particles such as solutions of coal liquefaction products from coal liquefaction plants.
Descrlption of the Prior Art A variety of chemical plants comprising a process - of reducing the pressure of high pressure liquids containing solid particles are known. Typical of such plants are coal liquefaction plants which have been recently reperceived accompanied by worsening of the condition of petroleum ` supply. In coal liquefaction plants, coal is pulverized a~d dehydrated, after which suitable solvents are added to the coal pieces to form a slurry. The slurry i~ pressurized and pre-heated, and is subjected to liquefaction by ;
` . ~, ,, ,,.1 ,,..... ~Z:116~t7 1 hydrogenation reaction. The resulting hlgh temperature and high pressure coal liquefaction solution product is subjected to the gas-liquid separation, followed by pressure reduction. Then, the heavy and light oil products are frac-tionally distilled as they are or after further gas-liquid separation. For the pressure reduction of the solution of coal liquefaction product, it is the usual practice to make use of the throttling e~fect of a flow regulator valve and is usuall~ call let-down valve. How-ever, a member of the valve which contacts with the solution tends to be considerably damaged by solid particle of organicmater contained in the solution. In view of the above fact, there has been proposed, for example, in Japanese Patent Application No. 56~108365~an apparatus in which pressure energy is recovered simultaneously with the pressure reduction of the high pressure liquid or solution.
In this energy recovery apparatus, the solution of coal liquefaction product is fed to a cylinder in whic~ the pressure energ~ is converted into and recovered as mechanical energy. The solution which has been reduced in pressure by the conve`rsion is fed to a subsequent step by the use of mechanical energy from other cylinders. However, the mechanical motion in the energy converter involves problems such as abrasion or erosion of and a thermal influence on sliding portions and valves which contact with the solution.
1167~7 SUMMhRY OF THE I NVENT I ON
It i~ accordinsly an obiect of the present invention to prov de a pressure reduction apparatus for solid particle-containing hi~h pressure solution~ or li~uid~
in which the damage by abrasion of valve~ or other members of the apparatus wh,ich directly come into contact with the liquids is reduced to a minilmum.
It is another object o~ the invention to provide a pressure reduction apparatus for solid particle-containing hish préssure liquids which is easy in maintenance and ha~
excetlent durability~
~t is a further object of the invention to provide a pressure reduction apparatu~ for solid particle-containing high pressure liquids in which energy of high pressure gas in the apparatus is recovered as mechanical or electric power upon reduction of the pre sure.
It i~ a still further object of the invention to provide a pressure reduction apparatus of the above-mentioned type in which feed of the high pressure liquid during the course of pressure reduction is controlled based on a detected amount of a gas in a pressure reduction unit.
It is another object of the invention to provide a pressure reduction apparatus of the above-mentioned type in which feed of the high pressure liquid or high and~or low pressure gas is effectively controlled by pressure .. . .
~2~ 6~7';' 1 control valves.
The above objects can be achieved, according to the invention, by a pressure reduction apparatus for 901 id particle-containing high pressure liquids which comprise~:
a gas and liquid pres~ure reduction tower having a ~as phase zone and a liquid phase zone;
a high pressiure gas and liquid separation tower which has a gas phase zone connected to the gas phase zone of said gas and liquid pressure reduction tower through a first line provided with a high pressure gas charge or discharge valve, and a liquid pha~e zoné connectèd to the liquid phase zone o~ said gas and liquid press~lre reduction tower through a second line having a feed valve for a liquid being reduced; and a low pressure gas and liquid separation tower which haY a gas phase zone connected to the gas phase zone through a third line ha~ins a low pressure gas charge or discharge valve, and a liquid phase zone connected to the liquid phase zone through a fourth line having a valve through which a pressure reduced liquid is discharged, in which prior to opening of the feed ~alve or the pressure-reduced liquid discharge valve, the high pressurè
gas charge or discharge valve, or the low pressure gas charge or discharge valve is opened thereby increasin~ or decreasing the pressure within a corresponding gas and ~21167~
1 liquid separation tower.
The gas and liquid separation tower may be made o~
a sinsle tower unit or a plurality o~ tower units each having a high pres~ure ~acl charge or discharge valve and a ; 5 low prec~sure gas charge or dischar~e valve arranged in a manner as recited in the above system.
The above and ot:her objects t ad~antage~ and features of the invention will become apparent from the following description with reference to the accompanying drawinss.
P~IFF DESCRIPTION OF THE INVENTION
Fig. 1 is a flow chart of a pressure reduction apparatus according to-one embodiment of the invention;
Flg. 2 is an indicator diagram of the apparatus of Fig. 1;
Fig. 3 is a time chart showing an opening and :
closing operation sequence of valves of the apparatus of Fig. 1;
Fig. 4 is a ~iew similar to Fig. 1 and show~
another embodiment of the~in~ention;
Fig. 5 is a diagram showing of the relatlon between the presclure and the recovered power in one pres~ure reduction tower of the apparatus of Fig. ~.;
Fi~. 6 is a flow chart showing a gas and liquid --- 1 2 ~ 1 ~ 7~
1 pressure reduction apparatus according to ~ further ernbodiment o~ the invention;
. Figs. 7(a) through 7(d) are illustr~tive views .. showing a variation of liquid level in one cycle of the gas 5 and liquid preseuure reduction tower of Fig. 6; and Fig. ~ is a block dia~ram of a control device used to carry out the controlling operation of the apparatus of Fig. 6; and Fig. 9 is a flow chart ~howing a pressure.reduction apparatus used in a coal liquefaction plant according.to ; another embodiment of the invention.
. DETAILED DESCRIPTION ~NO E~BODIMENTS OF THE lN~ENTION
i Broadly, the pressure redu._tion apparatus for solid particle-containing high pressure liquids according to 15 . the present invention is characterized by a gas and liquid pressure tower which hae~ a feed valve for a liquid bein~ ~
reduced and a discharge valve for a pressure-reduced liquid : at a lower side or zone thereof, and a high pressure gas charge or discharge valve and a low pressùre gas charge or discharge valve at an upper side or zone thereof. In this arrangement, the high pressure gas charge or discharge valve, or the low pressure gas charge or discharge valve is opened prior to opening of the feed valve for liquid being reduced or the reduced liquid discharge valve thereby ~ .
.
~2~16~7~7 increasing or decreasing the pressure in the apparatus.
ReFerring now to the accompanying drawings in which like parts are indicated by like numeral re~erence~
throushout the specification.
In Fi~. 1, there is shown a pres3ure reduction apparatus A o~ the present invention applied to a coal lique~action plant. In the figure, indicated at 1 i5 a high pressure gas and liquid sieparation tower used in a coal lique~action plant, at`2 is a feed line ~or a solution of coal lique-Faction product, and at 5 is a low pressure ga~
and liquid separation tower. Similarly, indicatèd at 11~
12, 13 are, re~pectively, gas and liquid pressure reduction towers, at 14, 15~ 16 are feed valves 14~ 15, 16 for a liquid being reduced in prerssure and at 17, 18, 19 are pressure-reduced liquid discharge ~alves. Indicated at 20, _ ::~ 21, 22 are low pressure gas charge or discharge valves and at 23, 24~ 25 are high pressure gas charge or discharye valves. The gas and liquid pressure reduction towers 11 through 13 are interconnected in parallel to each other though the valve~ 14 through 16, 17 through 1~, 20 through 22, and ?3 through 25, respectively. Further, the tower~ 11 through 13 are connected through the ~eed val~es 14 through 16 a~d a line 3 to the hiyh pressure gas and liquid separation tower 1 at the bottom thereof and also through the valves 23 through 25 and a line 4 to the tower 1 at the 12116'7~7 1 top thereof. On the other hand, the towers are also connected through the valves 17 through 19 and a 1 ine 6 to the lower pressure gas and liquid separation tower 5 at an intermediate portion thereof and through the valves 20 through 22 and a 1 ine 7 to the top of the tower S. Between the lines 3 and 6 is connected ~ ~y-pass line 9 having a pressure reduction valve 10 for safety purposes.
In operation, the individual gas and liquid pressure reduction towers 11 through 13 are operated bY sequence control o~ the respective valves in a cycle comprising liquid feed, pressure reduction, liquid discharge, and pressure elevation. This is particularly described with regard to the gas and liqùid pressure reduction tower 11 which is in a state where the pressure elevation step has completed~ In the state A of Fi~. 2 where the pressure elevation step has completed, the high pressure gas charge or discharge valve 2~ is opened ànd the other val~es 14, 17, 20 are closed. The level of liquid in the tower 11 is positioned at L1 of Fig. 2. When the feed valve 14 is opened, a high~pressure solution of coal liquefaction product (e.~. 250 kg/cm2~is fed from the gas and liquid separation tower 1 into the pres~ure reduction tower 11.
The liquid in the tower 11 is moved from A to B along the indicator dia~ram of Fig. 2, ~y which the level or the liquid rises from L1 to L3, after which the hi~h pres~ure lZ:~1677 1 yas ~:harge or discharge ~alve 23 i~ ~irst clo~ed and then the ~eed valve 14 is clo~ed. During this period, the hish -~ pressure ~as is flown backward through the line 4 and i~
released from a line 27. When the low pressure ~a~ charge or dischar~e valve 20 iCW opened, a ga~ dissolved in the solution within the tower 11 is discharged toward the l;ne 7 along with a remaining high pressure gas at the top of the pressure reduction tower 11~ As a consequence, the solution is reduced in pres~ure to a certain level (e~g. lQ0 kg~cm2~
(state B --~ state C). At the time, the level of the liquid in the pressure reduction tower 11 increases from L3 to L4, and the gas phase and the liquid phase in the tower 11 reach an equilibrium. In this state, the pressure-reduced liquid - discharge valve 17 is opened, by which the low pressure gas is passed from the valve ~into the pressure reduction tower 11 while dischargin~g the reduced solution of coal 1iquefaction product from the tower 11 into the low pressure .
~ gas and liquid separation tower 5 (state C --~ state D).
., .
-- Accordingly, the liquid le~el in the pressure reduction tower 11 decreases from L4 to L2. At the time when the state reaches D, the low pres~ure gas charse or dischar~e valve 20 is first closed and then the discharge valve 17 for the pressure-r~duced liquid is closed, followed by opening the high pressure gas char~e or discharge valve 23. By this, the liquid in the tower 11 increases in pres-~ure to .
_ 9 _ k B. q/~, 1 the same level as the high pressure gas (state D ---~ state A). The liquid level decreases from L2 to Ll. After reaching an equilibrium, the system is repeatedly subjected to a subse~uent cycle. Th:is operation cycle is effected on the respective gas and liquid pressure reduction towers, i.e. the towers are so operated that the liquid charge and discharge steps are continuously performed in one cycle, or the amounts of the solution of coal liquef~ction product passing through the lines :3 and 6 are maintained at constant levels. The time chart of opening and closing the gas and liquid pressure reduction to~ers 11, 12, 13 is shown in Fig.
3, in which the mark represent~d by ~ ' and '~z~'' means a state where each of designated valves is opened.
As will be apparent from the above, the pressure reduction apparatus of the invention is so operated that the pressure reduction of the liquid in the pressure reduction tower is effected by properly operating the high pressure gas charge or discharge valve and the low pressure gas charge or discharge valve, so that no erosion of the valves by solid particle of organicmater is involved. In addition, the feed valves of a liquid to be reduced and the pressure-reduced liquid discharge valves are opened or closed in such a state that there is no difference in pressure between the pressure reduction tower and either of the gas and liquid separation towers and no flow of liquid occurs. Accordinglv, abrasion ~ ,~0 lZ116 ~ 7 of the valves can be reduced to a substantial ex-tent.
Moreover. no slidin~ members such as a plunger and a piston as used in known apparatuses are used. This is very advantageous in that no ~ealing between the ~liding member - 5 and a cylinder is needed with ease in maintenance and a remarkable improvment o~ durability.
In th~ aDove embodiment, the operation o~ one gas and liquid pressure reduc:tion tower i9 il lustrated but a plurality of the towers as shown in Fig. 1 which have the respective high pressure gas charge or discharge valve~ and , the low pressure ~as charge or discharge valves connected parallel to one another will ensure constant flows of liquids charged or discharged from the gas and liquid ~ separation towers 1 and 5.
:`, 15 In accordance with another embodiment of the invention, there is recovered pressure energy as power at high efficiency. The energy recovery may be effected most simply, for example, by connecting an expansion machine G to `-; the line 27 of Fig. 1 through which the hi~h pressure ~as i5 passed backward as mentioned hereinbefore. In order to much more efficiently recover pressure energyt a feed valve and a first expansion machine connected in series are connected parallel to the high Presqure ga charge or discharge valve, and the high pressure gas is fed into the pressure reduction tower through the Yeries connection of .
`:
11 ~
lZ~6~7'7 1 the ~eed valve and the first expansion ma~hine. Moreover, another series circuit of an exhau~t valve for pressure reduction and a second expansion machine is connected in parallel to the low pressure ga~ charge or dischar~e valve.
The high pre~sure ga~ i~ exhausted through this series circuit. By this arrangennent, pres~ure energy can be recovered as power at the time o~ charge and di~charge of the high pressure gas. This i9 particularly ~e5crib~d in Fig. 4.
In the apparatus of Fi~. 4, there is provided a . series circuit compo~ed of gaq feed valves ~3' through 25' for Pressure elevation and a ~irst expansion machine G~ ~uch as a turbine associated in common with the sa3 feed valves 23 through 25 , This series circuit is arranged parallel to the high pressure gas ~aPge-o- discharge valves ~3 through 25. Likewi~e, in parallel to the charge ~r-~iIKJ~yir valves 20 through 22 for low pressure ga~ i~
provided another series circuit composed o~ exhaus-tion valves 20' through 22' for pressure reduction and a second expansion machine G2 such-as a turbine. For convenience' sake, the first and second expansion machines are ~eparately provided and are directly connected to generators G, respectively. It is preferable to arrange the rnachines in the same ali~nment.
It will be noted that the hi~h pressure gas ~r8e-- 12 - k. g- q/
1 2 ~ 7 1 . ~ diqcharge valve~ 23 through ~5 and the feed valveq 23' through 25 may be replaced by charge-over valves. This is true of the low pres~ure ~as ch~rge~3P-~s6ha~g~ valves 20 throu~h 22 and the exhaustion valve~ 20' throush 22'.
In operation, in the state.A of Fig. 2 where the pressure elevation has been complete, the valve~ 14, 17, 23, 23'~ 20 and 20' are all I ~ When the high pressure liquid feed valve 14 is opened and the high pressure gas ~ }~-3~-discharge valve 23 is opene-d, the liquid feed step starts (A -~ B). The high temperature high pressure liquid or solution is fed from the hi.gh pressure gas and liquid .
separation tower 1 through the line 3 to the pre~sure reduction tower 11 by which the liquid level in the tower increases from L1 to L3. At the time~ the high pressure gas in the pressure reduction tower 11 is pa~ed through the valve 23 and a line 28 into the line 4. When the liquid level reaches L3, the valve 23 is ~ ed and then-the high ~
pressure liquid charge or dis~harg~-valve 14 is closed to .
complete the feed of the liquid~ Subsequently, when the pressure reduction exhaustion valve 20' is opened, the pressure reduction step ~B ~ C o~ Fig. 2) starts in which not only the gas in the pres~ure reduction tower 11 but also a ga~ flushed from the liquid is fed throu~h the line 26 into the second expansion machine G2 such as a turbine. By this, the presYure energy is reco~ered as power - 13 - k-B. q////t~
~2116~7~
l in the machine G2. The gas whose pressure has been reduced is passed into the line 7. By the pressure reduction step, the liquid level in the pressure reduction tower ll increases from L3 to L~. The recovered energy decreases, as shown in Fig. 5, as the pressure within the tower 11 changes from an initial pressure P0 which is equal to the pressure within the high pressure gas and liquid separation tower l, to pressure P1 equal to the pressure within the low pressure gas and liquid separation tower 5.
At the time when the pressure within the pressure reduction tower ll reaches the pressure Pl within the low pressure gas and liquid separation tower, the valve 20' is closed and then the pressure-reduced liquid discharge valve 17 is opened. Low pressure gas cha~ge valve 20 is also opened to effect the discharge step (C~ D). That .is, the low pressure gas is passed from the gas and li~uid separation tower 5 through the line 7 and the valve 20 into the pressure reduction tower ll. On the other hand, the liquid or solution whose pressure has been reduced is discharged through the pressure reduction tower ll into the separation tower 5, b~ which the liquid level within the separation tower ll is dropped rom L4 to L2. There-aftex, the low pressure gas charge valve 20 is closed, after which the discharge valve 17 is closed to complete ~he discharge opera~ion. Upon opening of the ..
1 feed valve 23', the pres3ure elevation step (D -? A) starts. In this pressure elevation step, the high pressure gas from -the high pre~sure gas and liquid separation tower 1 acts to drive the first expansion machine 30 whereby the pres~ure energy i9 recoverecl as power. The gas is fed through the feed valve 23' into the pressure reduction tower 11. ~ccordingly, the pressure within the tower 11 gradually increases to a 1evel of the pressure P0 within the separation tower 1 or the pr-e~sure of the liquid in the line 3~ The liquid level in the tower 11 decreases from L2 to L1. As shown in Fi~. 5, the ener~y recovered by the first expansion machine decreases, similar to the case of the pressure reduction step, as the pressure within the pressure reduction tower 11 increases. When the pressure within the tower 11 reaches P0, the feed valve 23' is closed to complete the pres~ure elevation operation, follawed by a ~ubsequent cycle. This operation cycle is also effected in the same manner with respect to the other pressure reduction towers 12, 13.
In order to ensure proper operation of the pressure reduction apparatus of the type described above, it is necessary to open or close valves after the liquid le~el or pressure in the pressure reduction apparatus has reached a given value. Known level gauges of the differential pressure or electrostatic capacitance type need severe ~ .
67'7 1 temperature and pre~sure conditions, leading to many troubles. In order to overcome the above disadvantage, there are provided, according to a further embodiment of the invention, a first detector means in the line 4 connecting the high pre~sure gas and liquid separation tower 1 and the pre~sure red~ction tower 11 and a second detecting means in the line 7 connecting the preYqure reduction tower 11 and the low pressure gas and l~quid separation tower 5 thereb~
detecting quantities of ~ase~ charged or discharged through the high and low pressure s3as charge OF discharge valves 23 and 20, respectively. The feeds of hi~h and low pressure liquids charged into ahd discharged from the pressure reduction tower are controlled based on the detected gas quantities. This embodiment is based on the fact that under certain pressure and temperature conditions, a gas and a liquid have the same volume, so that an amount of liquid charged into or discharged from the gas and liquld pre~sure reduction tower is the same as an amount of liquid discharged from or charged into the tower. In other words, a change in liquid level in the tower is proportional to an amount of ~as char~ed into or discharged from the tower.
More particularly, when a liquid is charged into or discharged from the gas and liquid separation tower, arrival of the liquid level at a predeterrnined value is detected by an amount ~f ga3 charged into or discharged from the .
12~167~7 .
pressure reduction tower. Accordins to the detected signal, the high pressure liquid feed valve and the high pressure gas charse or discharge valve, or the low pressure liquid discharge valve and the low pres~ure ~as charge or discharge valve are so controlled ac~ to be closed, followed by openin0 `~ the low pressure ga~ charge or discharge va~ve or high pressure ~as charge or dlischarge valve. Although the opening o~ the high pressure liquid feed valve and the low pre~sure liquid discharsle valve may be effected after a predetermined pe~iod of time after the high or low pressure gas charge or discharge valve has been opened, it is preferable to detect inner pressures o~ the gas and liquid pres~ure reduction towert high pressure gas and liquid separ~tion tower, and low pressure ~as and liquid separation tower, and compare these pressures with one another. When the inner pressure within the pressure reduction tower with those pressure- within the seParation towers, the hi8h pressure liquid feed valve and the low pressure liquid discharge valve are opened.
Control of a li~uid charged into or discharged -from the pres~ure reduction tower is particularly described with reference to Fig. ~, in which indicated at D1 and 2 :: are, respectively, first and second detector means for . ~
` ` detecting -flow rates of gases charged into and discharged from the presC~ure reduction tower 11 and at L is a level :
: ~ 17 -~'2116t77 . 1 gauge for detectin~ the level of liquid in the tower 11.
.: For convenience' sake, only one pressure reduction tower 11 - is shown in Fis. 6 but a pluralitY of towers may be .controlled in the ~ame manner as described above.
The manner of control is illustrated with reference tc Figs. 7 and 8. In Fig. 8, indicated at 31 is a pre~sure - detector within the high preqsure gas and liquid separation.
- tower 1, at 32 is a pressure detector within the pressure - reduction tower 11, and at 33 is a pressure detector within . 10 a low pressure gas and liquid separation tower 5. At 35 i~
.: a critical char~e or discharge level settin~ means for a . liquid within the pressure reduction tower 11, at 36 is a `'. means for setting gas and liquid properties, and at 38 is a - ` calculator for capacities of various sections of the .~.~ 15 . pressure reduction tower 11. At 43 - 45 are comparators, a~
-; 50 is a an indicator of an amount of charge or discharge `.~ gas, at 52 is an actuator indicator~ and at 54 - 58 are A/D
-~. converters. At 59 is a D~A converter and at 60, 61 are , microcomputer~.
``r"~ 20 In operation, a suming that the gas and liquid -*~ pressure reduction apparatus A is in such a ~tate that the-.. " discharge of liquid has been accompli~hed a~ in Fi~. 6, the valve~ 14, 17, 20 and 23 are all closed. The liquid within ~" the pressure reduction tower 11 is at a critical discharge.
.~. 25 level L1 for the low pres~ure liquid. The amount o~ the :`
: .
, ~; . .
` - 18 ~
.
- lZ1~77 1 1 iquid is equal to an inner capacity of a zone of the pressure reduction tower 11 covering from the critical discharge level L1 to the bottom of the tower. The volume of the ~a~ is equal to a sum of an inner volume VQLL defined by the level L1 and the cril:ical level L3 for high pressure liquid feed and an inner volume VQR defined by the level L3 and the top of the tower 11" i.e. VQLL ~ vQa . The pressure within the tower 11 is the 3ame as the pressure P2 within the low pressure gas and li~uid separation tower 5. Under lQ these conditions, a signal is inputted from the microcomputer 60 through the D/A converter 59 to the actuator indicator 52 to energize a ~olenoid which act~ on an actuator of the high pressure gas char~e or discharge valve 23. When the valve 23 is opened, a predetermined amount of th~ hi~h pres~ure gas is fed from the separation tower 1 through the line 4 into the pressure reduction tower 11 thereby increasing the inner pressure of the tower 11 and compressing the liquid~ Accordinsly, the liquid level is dropped from L~ by a distance, LL, as shown in Fig. 7(b).
At this time~ an amount of the ga~ fed into the tower 11 is detected by the flow rate`detector D1 at the high pressure side. The output signal from the detector D1 i~ pa~sed through the A~D converter 57 into the comparator 43 and the microcomputer 61. In the microcomPuter 61, a variation of the liquid level accompanied by the charged high pre3sure ~ 19 -1 ~as is calculated to determine a liquid le~el at the time.
This is compared in the comparator 45 with a signal from the level setting means 35. An output signal from the comparator 45 iq inputted to the microcomputer 60 to check the level L1 in t:he liquid discharge step.
In orde~r to imProue the accuracy of the detection and operation of the liquid level, signals from the ~eans 36 and the pressu,re detectors 31 through 33 may be inpu-tted to the microcomputer 60 whose output ~i~nal is then passed into the, microcomputer 61.
Output signals from the pressure detectors 32 and 31 for detecting a pressure within the tower 11 and a pressure within the separation tower i are compared with each other. When,these pressures are detected as equal, a slgnal of opening the feed valve 14 from the microcomputer 60 i5 sent through the DfA converter 59 to the actuator indicator 52 thereby opening the valve 14. In a subsequent li~uid feed step, the high pressure liquid is fed from the separation tower 1 into the pressure reduction tower 11 and at the same time, the high pressure gas is pas~ed from the pressure reduction tower il throu~h the hi~h pressure gaq charge or di~charge valve 23 to the line 4. The line 4 i~-controlled at the side of the line 27 so that the pressure therein is held constant. An ou-tput si~nal corresponding to an amount of gas detected by the flow rate detector D1 is ~ ~20 --.
lZ11677 l compared in the comparator 43 with a ~isnal from the indicator 50 which is capable of outputting a signal corresponding tn an amount of an exhausted gas, VQLL ~ VQBB, nece~ary for liquid feed after reception of a ~i~nal from the critical level setting means 35 for the charge or discharge liquid in the pressure reduction tower. When the amounts agree with each other, the signal from the ~7 .
comparator ~is passed to t:he microc~mputer 6~, ~rom which a signal is passed through the D~A converter to the actuator indicator 52 so that the fe-ed valve 14 and the high pressure gas charge or dischar~e ~alve ~ are closed. A~ a reaultg the valves 14 and 23 are closed to complete the liquid ~eed stepj so that the amount of gas in the pressure reduction tower 11 is reduced to VQB as shown in Fig. 7(c).
After completion of the liquid feed step, the low pre~sure gas charge or discharge valve 20 is opened by a signal from the microcomputer 60. The high pre~sure saS in the pressure reduction tower 11 is discharged through the lines 7, 7' to outside. The pressure within the tower 11 is reduced to an inner pres~ure of the eparation tower 5. At thi~ time, an amount of gàs, ~QEP, released from the tower 11 into the line 7 is detected by the ~as flow rate detector D2 and an output si~nal from the detector D2 is sent, after A~D con~ersion, to the microcomputer 61 and the comparator 44. While the liquid le~el i9 checked by the microcomputer - 21 - ~.B '7/~/~
.
67'7.
1 . 61, the critical l evel L3 in the preceding step i~ checked ~rom a change, BB, caused by the pressure change. In this pressure reduction step, the liquid level increases from L3 to L4 whereas the amount o~ gas decreases to VQB - ~QBB a~
shown in Fi~, 7(d). It is detected from signals from the pressure detectors 32 and 33 that the pressure within the pressure reducti.on tower 11 becomes equal to.the pressure P
~ ~ 2 within the separation tower 5. After completion of ~
expansion step, a command: of opening the dischar~e valve 17 .10 is.outputted from the microcomputer 60 thereby opening the valve 17. In a subsequent liquid dîscharge step, the low pre~sure ~as is passed from the separation tower 5 to the ; pressure reduction tower 11 by an amount of VQBB + VQLL. ~t the same time, a pressure-reduced liquid is discharged from the pressure reduction tower 11 to the separation tower 5 in the same amount as the low pressure ~a9- The liquid ` level is lowered from L4 to L1. A signal corresponding to the amount of VQLL + ~QBB necessary ~or the liquid discharge is outputted from the indicator 50 according to the signal generated from the critical level setting means 35. This ~ignal is compared in the`comparator 43 with an output signal from the gas flow rate detector D2. An output signal generated from the comparator 44 when the compared si~nals agree to each other is sent -to the microcomputer 60, which ~enerates a command signal for closing the low pressure gas `
- 22 ~ k. ~. q/q ., .
67'7 1 charge or discharge val~e 2b and ~he low Pre~sure liquid discharge valve 17~ thereby closing the ~alves through the D~A converter 59 and the actuator indicator 52. This lead~
to the state o~ Fi~. 7(a).
Becau3e of the presence of solid particles in the `~ liquid which is subjected to the gas and liquid separation in the high pressure separation tower 1, there may occur -- accumulation of a precipitation in lines. Additionally, there is a fear of coking because no hydrogen is contained.
1~ This will cause a gradual increase in resistance ~f liquid flow. In order to overcom~ the above, it is necessary that heads a and b of Fig. 6 are made great and that valve and pipe diameters are also made large. However, this is disadvantageous from the standpoint of design and cost. To overcome this, there is provided, according to a still further embodiment of the invention, a pressure control valve between the high pre~sure gas and liquid separation -- tower and the high pressure gas charge or dischar~e val~e so that when a high pressure gas is transferred from the high pressure gas and liquid separation tower to the pressure ..
reduction tower, a pressure within the pressure reduction tower is set to be lower than a presYure within the separation tower. Likewise, a pressure control valve is provided between the low pressure gas charge or diqcharge valve and the low pressure gaq and liquid separation tower 50 ~ 23 -67 ~
that when a low pressure ~as is transferred From the pressure reduction tower to -the low presqure ga~ and l iquid separa t i on tower, a preqsure within the qeparation tower is set to be 1 ower than the pressure reduction tower.
This embodiment is particularly described with reference to Fig. 9.
The pre!3sUre reduction apparatus ~ of Fig. ~
includes the llne 4 havins the high pressure ga~ charge or discharge val~e 23. This l'ine 4 is branched into a feed lin,e 4a and ~ line 4b. The~ line 4~ris provided,with a first pressure control valve or F~ressure reduction valve 70 and a check valve 71 and is connected to the high pre~qure ga~ and liquid separation tower 1. The line 4b is provided with a second pressure control valve or relief valve 72 so that the gas From the high pressure gas and liquid separation tower 1 i9 discharged through a line 4c while keeping ;ts pressure energy as high as possible and a pressure within the -, pressure reduction tower 11 is set to be lower than a pressure within the separation tower 1. Because the high pressure gas in the high pressure gas and liquid separation tower 1 is also used as a`feed source for low pressure gas, the line 4b is branched to ~i~e a low pressure ~as feed line ' 4d. At the line 4d are provided a third pre~sure control valve or pressure reduction valve 73 and a stop valve 74 so that a pressure within the pressure reduction tower i1 at - 24 - k~ q/~/~
~21~6~7~
1 the time o~ liquid discharge is set to be hi~her than a pres~ure within the ~eparation tower 5. The line 4d is connected to a line 7, which i~ connected to the line 4 at one end and also to the lower pressure gas and liquid ~;s~
separation tower 5 through a-chcck valv~ 75. By the arrangement described abo~e, the liquid can be smoothly transferred from the high pressure gas and liquid separation ~ I
tower 1 to the pressure reduction tower ~ an~ al~o ~rom the tower 5 to the low pressure ~a~ and liquid separation tower by the use of pressure differences established therebetween.
In this embodiment,, the high pressure liquid feed ! ine 3 through which the high pressure liquid i~ ~ed ~rom the separation tower 1 to the pressure reduction tower 11 and the pressure-reduced liquid discharge line 6 through which the pressure-reduced liquid is fed ~rom the pressure reduction tower 11 to the low pressure gas and liquid separation tower 11 may be arran~ed in the same line as shown in Fig. 9. Additionally, the separation tower-1, the pressure reduction tower 11 and the separation tower 5 may be arranged substantially in the same level o~ space.
In operation, assuming that the liquid discharge ~`SLI~a~ 5 step has now completed, the c~ valve~ ~*~ ~5 ~
opened and a pressure P1 within the pressure reduction tower 11 is equal to a pressure P'~ within the low pressure gas and liquid separation tower 5. In thi~ state, whèn the high - 25 - ` k,Q, q/q /~
~ 7 1 pressure gas charge or discharge valve 23 is opened, the hi~h pressure gas in the qeparation tower 1 is reduced in pressure by the first pressure control valve 70, -For example, from 250kg/cm2 to 240 kg~cm2. Thi~ gas is fed through the check valve 71 and the high pressure ~as char~e or discharge vslve 23 into the pressure reduction tower 1~, by which the precssure P1 in the tower 11 increases to a level preset b~ the firqt and second pressure control valves 70 and 72. At that time, the other valves are all closed.
When the pressure P1 within the pressure reduction tower 11 reaches a preset level, thle check valve 71 is closed to complete the compre~sion or pressure elevation step.
In a subsequent liquid feed step, the liquid within the high pressure gas and liquid separation tower 1 is fed to the pressure reduction tower 11 by the difference between the pressure P'1 within the pres~ure reduction tower 11 set by the first and second pressure control valves 70, 7~ and the pressure P0 in the high pressure gas and liquid separation tower 1 ad also by the difference in head between the liquid levels of both the towers. The gas in the pressure reduction tower 11 i~ dischar~ed through the line 23 to the line 4c including the second pressure contro1 valve ~.
When the liquid is fed to the upper limit level L3 f the pressure r~duction tower 1l, the high pressure ~as - 26 - k ~ ?/q/
, . ... , . ~ .
16'7~
1 charge or aischarge valve 23 is closed and the check valve 71 is opened to complete the liquid feed step.
In a subse~uent pressure reduction step, the high pressure gas in the pressure reduction tower 11 is discharged throuqh the low pressure gas discharge line 7 including the dislcharge va;lve 75 to the low pressure gas and liquid separation tower 5. The pressure Pl within the pressure reduction tower 11 is reduced to a level of the preset pressure P'Oof the separation towe~ 5. Accordingly, the liquid in the pressure reduction tower 11 is expanded resulting in an increase of the liquid level to a level L4.
When the pressure Pl within the pressure reduction tower 11 is reduced to the preset pressure P~o within the low pressure gas and liquid separation tower S, e~g. 100 kg/cm2, the discharge valve 75 is closed to complete the pressure reduction step. When the liquid discharge valve 19 is opened and the charge valve 74 is opened, the li~uid discharge step commences.
In the liquid discharge step, the high pressure gas which is passed through the high pressure feed line 4a and the high pressure gas discharge line 4b to the low pressure gas feed line 4d acts on the liquid within the pressure reduction tower 11 as a pressure P'l set by the third pressure control valve or pressure reduction valve 73, e.g.
110 kg/cm2. Accordingly, by the pressure difference be~ween lZ1~7~
1 the set pressure P'l and the pressure Po set within the low pressure gas and li~uid separation tower 5, i.e. ~P2 = P'o - P'l, and the head differen~e between the liquid levels in both the towers, the pressure-reducea liquid is fed from the pressure reduction tower 11 to the separation tower 5. At the time when the liquid level in the pressure reduction tower 11 is dropp,ed to Ll, the charge valve 74 is closed followed hy closing the pressure-reduced li~uid discharge valve 17 thereby completing the liquid discharge step.
In the above embodiment, one pressure reduction tQWer is used but a plurality of pressure reduction towers may be connected in parallel to one another. The plurality of towers are operated in different phases of operation cycle so that the high pressure liquid is continuously discharged from the high pressure gas and liquid separation tower along with a continuously feed of pressure-reduced liquid to the low pressure gas and liquid separation tower.
As described above, at the time of feeding of liquid to the pressure reduction tower 11 and also of discharge of liquid from the tower 11, a pressure within a tower located upstream of the tower is made higher than a pressure of the downstream tower. The liquid is fed from one tower to another by the use of pressure differences ~P
and ~P2 and head differences among associated towers.
t7 1 Accordingly, upon takiny into account an increase and a decrease in liquid level within the pressure reduction tower caused by the expan~ion of liquid at the time of pres~ure redu~tion and the compres~ion of liquid at the time of pre55ure elevation, it is preferable to de~ign -the pre~ure reduction tower 11 as follow~. That is, the pre~sure reduction tower 11 is so desisned a~ to have a lensth, 1, so that its top is higher by e than a preset liquid level L5 of the high pressure gas and lliquid separation tower 1 and the bo-~tom is lower by f than Zl preset le~el L6 ~ the lower pres~ure ~as and liquid sepration tower 5. By this, the liquid level in the pressure reduction tower 11 reache~ an equilibrium at a le~el where a pressure a~ point A in the pressure reduction tower 11 becomes equal to a pressure at points BJ B' of the high and low pressure gas and liquid separation towers 1 and 5 which are at the ~ame level as the point A. Accordingly, if the pressure difference between the pre~et pressure P0 within the high pressure 3as and liquid separation tower 1 and the pressure P'1 within the pressure reduction tower 11 at the time of feed o~ liquid, i.e. ~P1 = P0 - P'1, and the difference between the pressure P~1 within the pres~ure reduction tower 11 and the preset pressure P'0 within the low pressure gas and liquid separation tower 5 at the time of liquid di~charge, i.e. a?2 = P' ~ P-1 are set accor~ing to the length~ e and f, the _ ~9 _ .
12116'77 1 liquid level does not increase over a preset level nor decrease below a preset leuel. Accordingly, the pressure reduction apparatus can be operated only by time control.
In addition, when the pressure difference~ aP1 and ~P2 are set to correspond to head los~e~ by pipes and valve~, it i~
possible that a level di~erence, c, at the time of complete of the liquid feed and a level difterence, d, at the time of completion of the liquid discharge can be made zero.
Moreover, a gas flow detector such as a difPerential pressure detector 76 is provided at the line 4 connected to the pres~ure reductio ~ At the time when the gas flow rate reaches below a certain level, the liquid level within the pressure reduction tower 11 is regarded as reaching the level L3 or L1 thereby appropriately controlling the values.
~y this, a level gauge i~ not needed for the control of the valve~. The control of the pressure reduction apparatuq .
without use of sny level gauge maY be applied to the embodiment of Fig. 6. In this case, an overall length o~
the Pressure reduction tower~is properly set similar to the 2û case of Fig. 90 A differential pre~sure detector ~lS
provided at the ga~ line ~ of Fig. 6 through which a gas is charged or discharged to the pressure reduction tower 11.
Valve control is effected in a manner similar to the above embodiment.
~ 30 - k B q~q/ 8 . .
PRESSURE REDUCTION APPARATUS FOR SOLID
PARTICLE-CONTAINING HIGH PRESSURE LIQUIDS
. Field of the Invention This invention relates to a pressure reduction : ,.
apparatus for solid particle-contàining hi~h pres~ure liquids and more particularly, to a Pre~sure reduction apparatus for use in chemical plants which deal with high ;~ pressure liquids comprising solid particles such as solutions of coal liquefaction products from coal liquefaction plants.
Descrlption of the Prior Art A variety of chemical plants comprising a process - of reducing the pressure of high pressure liquids containing solid particles are known. Typical of such plants are coal liquefaction plants which have been recently reperceived accompanied by worsening of the condition of petroleum ` supply. In coal liquefaction plants, coal is pulverized a~d dehydrated, after which suitable solvents are added to the coal pieces to form a slurry. The slurry i~ pressurized and pre-heated, and is subjected to liquefaction by ;
` . ~, ,, ,,.1 ,,..... ~Z:116~t7 1 hydrogenation reaction. The resulting hlgh temperature and high pressure coal liquefaction solution product is subjected to the gas-liquid separation, followed by pressure reduction. Then, the heavy and light oil products are frac-tionally distilled as they are or after further gas-liquid separation. For the pressure reduction of the solution of coal liquefaction product, it is the usual practice to make use of the throttling e~fect of a flow regulator valve and is usuall~ call let-down valve. How-ever, a member of the valve which contacts with the solution tends to be considerably damaged by solid particle of organicmater contained in the solution. In view of the above fact, there has been proposed, for example, in Japanese Patent Application No. 56~108365~an apparatus in which pressure energy is recovered simultaneously with the pressure reduction of the high pressure liquid or solution.
In this energy recovery apparatus, the solution of coal liquefaction product is fed to a cylinder in whic~ the pressure energ~ is converted into and recovered as mechanical energy. The solution which has been reduced in pressure by the conve`rsion is fed to a subsequent step by the use of mechanical energy from other cylinders. However, the mechanical motion in the energy converter involves problems such as abrasion or erosion of and a thermal influence on sliding portions and valves which contact with the solution.
1167~7 SUMMhRY OF THE I NVENT I ON
It i~ accordinsly an obiect of the present invention to prov de a pressure reduction apparatus for solid particle-containing hi~h pressure solution~ or li~uid~
in which the damage by abrasion of valve~ or other members of the apparatus wh,ich directly come into contact with the liquids is reduced to a minilmum.
It is another object o~ the invention to provide a pressure reduction apparatus for solid particle-containing hish préssure liquids which is easy in maintenance and ha~
excetlent durability~
~t is a further object of the invention to provide a pressure reduction apparatu~ for solid particle-containing high pressure liquids in which energy of high pressure gas in the apparatus is recovered as mechanical or electric power upon reduction of the pre sure.
It i~ a still further object of the invention to provide a pressure reduction apparatus of the above-mentioned type in which feed of the high pressure liquid during the course of pressure reduction is controlled based on a detected amount of a gas in a pressure reduction unit.
It is another object of the invention to provide a pressure reduction apparatus of the above-mentioned type in which feed of the high pressure liquid or high and~or low pressure gas is effectively controlled by pressure .. . .
~2~ 6~7';' 1 control valves.
The above objects can be achieved, according to the invention, by a pressure reduction apparatus for 901 id particle-containing high pressure liquids which comprise~:
a gas and liquid pres~ure reduction tower having a ~as phase zone and a liquid phase zone;
a high pressiure gas and liquid separation tower which has a gas phase zone connected to the gas phase zone of said gas and liquid pressure reduction tower through a first line provided with a high pressure gas charge or discharge valve, and a liquid pha~e zoné connectèd to the liquid phase zone o~ said gas and liquid press~lre reduction tower through a second line having a feed valve for a liquid being reduced; and a low pressure gas and liquid separation tower which haY a gas phase zone connected to the gas phase zone through a third line ha~ins a low pressure gas charge or discharge valve, and a liquid phase zone connected to the liquid phase zone through a fourth line having a valve through which a pressure reduced liquid is discharged, in which prior to opening of the feed ~alve or the pressure-reduced liquid discharge valve, the high pressurè
gas charge or discharge valve, or the low pressure gas charge or discharge valve is opened thereby increasin~ or decreasing the pressure within a corresponding gas and ~21167~
1 liquid separation tower.
The gas and liquid separation tower may be made o~
a sinsle tower unit or a plurality o~ tower units each having a high pres~ure ~acl charge or discharge valve and a ; 5 low prec~sure gas charge or dischar~e valve arranged in a manner as recited in the above system.
The above and ot:her objects t ad~antage~ and features of the invention will become apparent from the following description with reference to the accompanying drawinss.
P~IFF DESCRIPTION OF THE INVENTION
Fig. 1 is a flow chart of a pressure reduction apparatus according to-one embodiment of the invention;
Flg. 2 is an indicator diagram of the apparatus of Fig. 1;
Fig. 3 is a time chart showing an opening and :
closing operation sequence of valves of the apparatus of Fig. 1;
Fig. 4 is a ~iew similar to Fig. 1 and show~
another embodiment of the~in~ention;
Fig. 5 is a diagram showing of the relatlon between the presclure and the recovered power in one pres~ure reduction tower of the apparatus of Fig. ~.;
Fi~. 6 is a flow chart showing a gas and liquid --- 1 2 ~ 1 ~ 7~
1 pressure reduction apparatus according to ~ further ernbodiment o~ the invention;
. Figs. 7(a) through 7(d) are illustr~tive views .. showing a variation of liquid level in one cycle of the gas 5 and liquid preseuure reduction tower of Fig. 6; and Fig. ~ is a block dia~ram of a control device used to carry out the controlling operation of the apparatus of Fig. 6; and Fig. 9 is a flow chart ~howing a pressure.reduction apparatus used in a coal liquefaction plant according.to ; another embodiment of the invention.
. DETAILED DESCRIPTION ~NO E~BODIMENTS OF THE lN~ENTION
i Broadly, the pressure redu._tion apparatus for solid particle-containing high pressure liquids according to 15 . the present invention is characterized by a gas and liquid pressure tower which hae~ a feed valve for a liquid bein~ ~
reduced and a discharge valve for a pressure-reduced liquid : at a lower side or zone thereof, and a high pressure gas charge or discharge valve and a low pressùre gas charge or discharge valve at an upper side or zone thereof. In this arrangement, the high pressure gas charge or discharge valve, or the low pressure gas charge or discharge valve is opened prior to opening of the feed valve for liquid being reduced or the reduced liquid discharge valve thereby ~ .
.
~2~16~7~7 increasing or decreasing the pressure in the apparatus.
ReFerring now to the accompanying drawings in which like parts are indicated by like numeral re~erence~
throushout the specification.
In Fi~. 1, there is shown a pres3ure reduction apparatus A o~ the present invention applied to a coal lique~action plant. In the figure, indicated at 1 i5 a high pressure gas and liquid sieparation tower used in a coal lique~action plant, at`2 is a feed line ~or a solution of coal lique-Faction product, and at 5 is a low pressure ga~
and liquid separation tower. Similarly, indicatèd at 11~
12, 13 are, re~pectively, gas and liquid pressure reduction towers, at 14, 15~ 16 are feed valves 14~ 15, 16 for a liquid being reduced in prerssure and at 17, 18, 19 are pressure-reduced liquid discharge ~alves. Indicated at 20, _ ::~ 21, 22 are low pressure gas charge or discharge valves and at 23, 24~ 25 are high pressure gas charge or discharye valves. The gas and liquid pressure reduction towers 11 through 13 are interconnected in parallel to each other though the valve~ 14 through 16, 17 through 1~, 20 through 22, and ?3 through 25, respectively. Further, the tower~ 11 through 13 are connected through the ~eed val~es 14 through 16 a~d a line 3 to the hiyh pressure gas and liquid separation tower 1 at the bottom thereof and also through the valves 23 through 25 and a line 4 to the tower 1 at the 12116'7~7 1 top thereof. On the other hand, the towers are also connected through the valves 17 through 19 and a 1 ine 6 to the lower pressure gas and liquid separation tower 5 at an intermediate portion thereof and through the valves 20 through 22 and a 1 ine 7 to the top of the tower S. Between the lines 3 and 6 is connected ~ ~y-pass line 9 having a pressure reduction valve 10 for safety purposes.
In operation, the individual gas and liquid pressure reduction towers 11 through 13 are operated bY sequence control o~ the respective valves in a cycle comprising liquid feed, pressure reduction, liquid discharge, and pressure elevation. This is particularly described with regard to the gas and liqùid pressure reduction tower 11 which is in a state where the pressure elevation step has completed~ In the state A of Fi~. 2 where the pressure elevation step has completed, the high pressure gas charge or discharge valve 2~ is opened ànd the other val~es 14, 17, 20 are closed. The level of liquid in the tower 11 is positioned at L1 of Fig. 2. When the feed valve 14 is opened, a high~pressure solution of coal liquefaction product (e.~. 250 kg/cm2~is fed from the gas and liquid separation tower 1 into the pres~ure reduction tower 11.
The liquid in the tower 11 is moved from A to B along the indicator dia~ram of Fig. 2, ~y which the level or the liquid rises from L1 to L3, after which the hi~h pres~ure lZ:~1677 1 yas ~:harge or discharge ~alve 23 i~ ~irst clo~ed and then the ~eed valve 14 is clo~ed. During this period, the hish -~ pressure ~as is flown backward through the line 4 and i~
released from a line 27. When the low pressure ~a~ charge or dischar~e valve 20 iCW opened, a ga~ dissolved in the solution within the tower 11 is discharged toward the l;ne 7 along with a remaining high pressure gas at the top of the pressure reduction tower 11~ As a consequence, the solution is reduced in pres~ure to a certain level (e~g. lQ0 kg~cm2~
(state B --~ state C). At the time, the level of the liquid in the pressure reduction tower 11 increases from L3 to L4, and the gas phase and the liquid phase in the tower 11 reach an equilibrium. In this state, the pressure-reduced liquid - discharge valve 17 is opened, by which the low pressure gas is passed from the valve ~into the pressure reduction tower 11 while dischargin~g the reduced solution of coal 1iquefaction product from the tower 11 into the low pressure .
~ gas and liquid separation tower 5 (state C --~ state D).
., .
-- Accordingly, the liquid le~el in the pressure reduction tower 11 decreases from L4 to L2. At the time when the state reaches D, the low pres~ure gas charse or dischar~e valve 20 is first closed and then the discharge valve 17 for the pressure-r~duced liquid is closed, followed by opening the high pressure gas char~e or discharge valve 23. By this, the liquid in the tower 11 increases in pres-~ure to .
_ 9 _ k B. q/~, 1 the same level as the high pressure gas (state D ---~ state A). The liquid level decreases from L2 to Ll. After reaching an equilibrium, the system is repeatedly subjected to a subse~uent cycle. Th:is operation cycle is effected on the respective gas and liquid pressure reduction towers, i.e. the towers are so operated that the liquid charge and discharge steps are continuously performed in one cycle, or the amounts of the solution of coal liquef~ction product passing through the lines :3 and 6 are maintained at constant levels. The time chart of opening and closing the gas and liquid pressure reduction to~ers 11, 12, 13 is shown in Fig.
3, in which the mark represent~d by ~ ' and '~z~'' means a state where each of designated valves is opened.
As will be apparent from the above, the pressure reduction apparatus of the invention is so operated that the pressure reduction of the liquid in the pressure reduction tower is effected by properly operating the high pressure gas charge or discharge valve and the low pressure gas charge or discharge valve, so that no erosion of the valves by solid particle of organicmater is involved. In addition, the feed valves of a liquid to be reduced and the pressure-reduced liquid discharge valves are opened or closed in such a state that there is no difference in pressure between the pressure reduction tower and either of the gas and liquid separation towers and no flow of liquid occurs. Accordinglv, abrasion ~ ,~0 lZ116 ~ 7 of the valves can be reduced to a substantial ex-tent.
Moreover. no slidin~ members such as a plunger and a piston as used in known apparatuses are used. This is very advantageous in that no ~ealing between the ~liding member - 5 and a cylinder is needed with ease in maintenance and a remarkable improvment o~ durability.
In th~ aDove embodiment, the operation o~ one gas and liquid pressure reduc:tion tower i9 il lustrated but a plurality of the towers as shown in Fig. 1 which have the respective high pressure gas charge or discharge valve~ and , the low pressure ~as charge or discharge valves connected parallel to one another will ensure constant flows of liquids charged or discharged from the gas and liquid ~ separation towers 1 and 5.
:`, 15 In accordance with another embodiment of the invention, there is recovered pressure energy as power at high efficiency. The energy recovery may be effected most simply, for example, by connecting an expansion machine G to `-; the line 27 of Fig. 1 through which the hi~h pressure ~as i5 passed backward as mentioned hereinbefore. In order to much more efficiently recover pressure energyt a feed valve and a first expansion machine connected in series are connected parallel to the high Presqure ga charge or discharge valve, and the high pressure gas is fed into the pressure reduction tower through the Yeries connection of .
`:
11 ~
lZ~6~7'7 1 the ~eed valve and the first expansion ma~hine. Moreover, another series circuit of an exhau~t valve for pressure reduction and a second expansion machine is connected in parallel to the low pressure ga~ charge or dischar~e valve.
The high pre~sure ga~ i~ exhausted through this series circuit. By this arrangennent, pres~ure energy can be recovered as power at the time o~ charge and di~charge of the high pressure gas. This i9 particularly ~e5crib~d in Fig. 4.
In the apparatus of Fi~. 4, there is provided a . series circuit compo~ed of gaq feed valves ~3' through 25' for Pressure elevation and a ~irst expansion machine G~ ~uch as a turbine associated in common with the sa3 feed valves 23 through 25 , This series circuit is arranged parallel to the high pressure gas ~aPge-o- discharge valves ~3 through 25. Likewi~e, in parallel to the charge ~r-~iIKJ~yir valves 20 through 22 for low pressure ga~ i~
provided another series circuit composed o~ exhaus-tion valves 20' through 22' for pressure reduction and a second expansion machine G2 such-as a turbine. For convenience' sake, the first and second expansion machines are ~eparately provided and are directly connected to generators G, respectively. It is preferable to arrange the rnachines in the same ali~nment.
It will be noted that the hi~h pressure gas ~r8e-- 12 - k. g- q/
1 2 ~ 7 1 . ~ diqcharge valve~ 23 through ~5 and the feed valveq 23' through 25 may be replaced by charge-over valves. This is true of the low pres~ure ~as ch~rge~3P-~s6ha~g~ valves 20 throu~h 22 and the exhaustion valve~ 20' throush 22'.
In operation, in the state.A of Fig. 2 where the pressure elevation has been complete, the valve~ 14, 17, 23, 23'~ 20 and 20' are all I ~ When the high pressure liquid feed valve 14 is opened and the high pressure gas ~ }~-3~-discharge valve 23 is opene-d, the liquid feed step starts (A -~ B). The high temperature high pressure liquid or solution is fed from the hi.gh pressure gas and liquid .
separation tower 1 through the line 3 to the pre~sure reduction tower 11 by which the liquid level in the tower increases from L1 to L3. At the time~ the high pressure gas in the pressure reduction tower 11 is pa~ed through the valve 23 and a line 28 into the line 4. When the liquid level reaches L3, the valve 23 is ~ ed and then-the high ~
pressure liquid charge or dis~harg~-valve 14 is closed to .
complete the feed of the liquid~ Subsequently, when the pressure reduction exhaustion valve 20' is opened, the pressure reduction step ~B ~ C o~ Fig. 2) starts in which not only the gas in the pres~ure reduction tower 11 but also a ga~ flushed from the liquid is fed throu~h the line 26 into the second expansion machine G2 such as a turbine. By this, the presYure energy is reco~ered as power - 13 - k-B. q////t~
~2116~7~
l in the machine G2. The gas whose pressure has been reduced is passed into the line 7. By the pressure reduction step, the liquid level in the pressure reduction tower ll increases from L3 to L~. The recovered energy decreases, as shown in Fig. 5, as the pressure within the tower 11 changes from an initial pressure P0 which is equal to the pressure within the high pressure gas and liquid separation tower l, to pressure P1 equal to the pressure within the low pressure gas and liquid separation tower 5.
At the time when the pressure within the pressure reduction tower ll reaches the pressure Pl within the low pressure gas and liquid separation tower, the valve 20' is closed and then the pressure-reduced liquid discharge valve 17 is opened. Low pressure gas cha~ge valve 20 is also opened to effect the discharge step (C~ D). That .is, the low pressure gas is passed from the gas and li~uid separation tower 5 through the line 7 and the valve 20 into the pressure reduction tower ll. On the other hand, the liquid or solution whose pressure has been reduced is discharged through the pressure reduction tower ll into the separation tower 5, b~ which the liquid level within the separation tower ll is dropped rom L4 to L2. There-aftex, the low pressure gas charge valve 20 is closed, after which the discharge valve 17 is closed to complete ~he discharge opera~ion. Upon opening of the ..
1 feed valve 23', the pres3ure elevation step (D -? A) starts. In this pressure elevation step, the high pressure gas from -the high pre~sure gas and liquid separation tower 1 acts to drive the first expansion machine 30 whereby the pres~ure energy i9 recoverecl as power. The gas is fed through the feed valve 23' into the pressure reduction tower 11. ~ccordingly, the pressure within the tower 11 gradually increases to a 1evel of the pressure P0 within the separation tower 1 or the pr-e~sure of the liquid in the line 3~ The liquid level in the tower 11 decreases from L2 to L1. As shown in Fi~. 5, the ener~y recovered by the first expansion machine decreases, similar to the case of the pressure reduction step, as the pressure within the pressure reduction tower 11 increases. When the pressure within the tower 11 reaches P0, the feed valve 23' is closed to complete the pres~ure elevation operation, follawed by a ~ubsequent cycle. This operation cycle is also effected in the same manner with respect to the other pressure reduction towers 12, 13.
In order to ensure proper operation of the pressure reduction apparatus of the type described above, it is necessary to open or close valves after the liquid le~el or pressure in the pressure reduction apparatus has reached a given value. Known level gauges of the differential pressure or electrostatic capacitance type need severe ~ .
67'7 1 temperature and pre~sure conditions, leading to many troubles. In order to overcome the above disadvantage, there are provided, according to a further embodiment of the invention, a first detector means in the line 4 connecting the high pre~sure gas and liquid separation tower 1 and the pre~sure red~ction tower 11 and a second detecting means in the line 7 connecting the preYqure reduction tower 11 and the low pressure gas and l~quid separation tower 5 thereb~
detecting quantities of ~ase~ charged or discharged through the high and low pressure s3as charge OF discharge valves 23 and 20, respectively. The feeds of hi~h and low pressure liquids charged into ahd discharged from the pressure reduction tower are controlled based on the detected gas quantities. This embodiment is based on the fact that under certain pressure and temperature conditions, a gas and a liquid have the same volume, so that an amount of liquid charged into or discharged from the gas and liquld pre~sure reduction tower is the same as an amount of liquid discharged from or charged into the tower. In other words, a change in liquid level in the tower is proportional to an amount of ~as char~ed into or discharged from the tower.
More particularly, when a liquid is charged into or discharged from the gas and liquid separation tower, arrival of the liquid level at a predeterrnined value is detected by an amount ~f ga3 charged into or discharged from the .
12~167~7 .
pressure reduction tower. Accordins to the detected signal, the high pressure liquid feed valve and the high pressure gas charse or discharge valve, or the low pressure liquid discharge valve and the low pres~ure ~as charge or discharge valve are so controlled ac~ to be closed, followed by openin0 `~ the low pressure ga~ charge or discharge va~ve or high pressure ~as charge or dlischarge valve. Although the opening o~ the high pressure liquid feed valve and the low pre~sure liquid discharsle valve may be effected after a predetermined pe~iod of time after the high or low pressure gas charge or discharge valve has been opened, it is preferable to detect inner pressures o~ the gas and liquid pres~ure reduction towert high pressure gas and liquid separ~tion tower, and low pressure ~as and liquid separation tower, and compare these pressures with one another. When the inner pressure within the pressure reduction tower with those pressure- within the seParation towers, the hi8h pressure liquid feed valve and the low pressure liquid discharge valve are opened.
Control of a li~uid charged into or discharged -from the pres~ure reduction tower is particularly described with reference to Fig. ~, in which indicated at D1 and 2 :: are, respectively, first and second detector means for . ~
` ` detecting -flow rates of gases charged into and discharged from the presC~ure reduction tower 11 and at L is a level :
: ~ 17 -~'2116t77 . 1 gauge for detectin~ the level of liquid in the tower 11.
.: For convenience' sake, only one pressure reduction tower 11 - is shown in Fis. 6 but a pluralitY of towers may be .controlled in the ~ame manner as described above.
The manner of control is illustrated with reference tc Figs. 7 and 8. In Fig. 8, indicated at 31 is a pre~sure - detector within the high preqsure gas and liquid separation.
- tower 1, at 32 is a pressure detector within the pressure - reduction tower 11, and at 33 is a pressure detector within . 10 a low pressure gas and liquid separation tower 5. At 35 i~
.: a critical char~e or discharge level settin~ means for a . liquid within the pressure reduction tower 11, at 36 is a `'. means for setting gas and liquid properties, and at 38 is a - ` calculator for capacities of various sections of the .~.~ 15 . pressure reduction tower 11. At 43 - 45 are comparators, a~
-; 50 is a an indicator of an amount of charge or discharge `.~ gas, at 52 is an actuator indicator~ and at 54 - 58 are A/D
-~. converters. At 59 is a D~A converter and at 60, 61 are , microcomputer~.
``r"~ 20 In operation, a suming that the gas and liquid -*~ pressure reduction apparatus A is in such a ~tate that the-.. " discharge of liquid has been accompli~hed a~ in Fi~. 6, the valve~ 14, 17, 20 and 23 are all closed. The liquid within ~" the pressure reduction tower 11 is at a critical discharge.
.~. 25 level L1 for the low pres~ure liquid. The amount o~ the :`
: .
, ~; . .
` - 18 ~
.
- lZ1~77 1 1 iquid is equal to an inner capacity of a zone of the pressure reduction tower 11 covering from the critical discharge level L1 to the bottom of the tower. The volume of the ~a~ is equal to a sum of an inner volume VQLL defined by the level L1 and the cril:ical level L3 for high pressure liquid feed and an inner volume VQR defined by the level L3 and the top of the tower 11" i.e. VQLL ~ vQa . The pressure within the tower 11 is the 3ame as the pressure P2 within the low pressure gas and li~uid separation tower 5. Under lQ these conditions, a signal is inputted from the microcomputer 60 through the D/A converter 59 to the actuator indicator 52 to energize a ~olenoid which act~ on an actuator of the high pressure gas char~e or discharge valve 23. When the valve 23 is opened, a predetermined amount of th~ hi~h pres~ure gas is fed from the separation tower 1 through the line 4 into the pressure reduction tower 11 thereby increasing the inner pressure of the tower 11 and compressing the liquid~ Accordinsly, the liquid level is dropped from L~ by a distance, LL, as shown in Fig. 7(b).
At this time~ an amount of the ga~ fed into the tower 11 is detected by the flow rate`detector D1 at the high pressure side. The output signal from the detector D1 i~ pa~sed through the A~D converter 57 into the comparator 43 and the microcomputer 61. In the microcomPuter 61, a variation of the liquid level accompanied by the charged high pre3sure ~ 19 -1 ~as is calculated to determine a liquid le~el at the time.
This is compared in the comparator 45 with a signal from the level setting means 35. An output signal from the comparator 45 iq inputted to the microcomputer 60 to check the level L1 in t:he liquid discharge step.
In orde~r to imProue the accuracy of the detection and operation of the liquid level, signals from the ~eans 36 and the pressu,re detectors 31 through 33 may be inpu-tted to the microcomputer 60 whose output ~i~nal is then passed into the, microcomputer 61.
Output signals from the pressure detectors 32 and 31 for detecting a pressure within the tower 11 and a pressure within the separation tower i are compared with each other. When,these pressures are detected as equal, a slgnal of opening the feed valve 14 from the microcomputer 60 i5 sent through the DfA converter 59 to the actuator indicator 52 thereby opening the valve 14. In a subsequent li~uid feed step, the high pressure liquid is fed from the separation tower 1 into the pressure reduction tower 11 and at the same time, the high pressure gas is pas~ed from the pressure reduction tower il throu~h the hi~h pressure gaq charge or di~charge valve 23 to the line 4. The line 4 i~-controlled at the side of the line 27 so that the pressure therein is held constant. An ou-tput si~nal corresponding to an amount of gas detected by the flow rate detector D1 is ~ ~20 --.
lZ11677 l compared in the comparator 43 with a ~isnal from the indicator 50 which is capable of outputting a signal corresponding tn an amount of an exhausted gas, VQLL ~ VQBB, nece~ary for liquid feed after reception of a ~i~nal from the critical level setting means 35 for the charge or discharge liquid in the pressure reduction tower. When the amounts agree with each other, the signal from the ~7 .
comparator ~is passed to t:he microc~mputer 6~, ~rom which a signal is passed through the D~A converter to the actuator indicator 52 so that the fe-ed valve 14 and the high pressure gas charge or dischar~e ~alve ~ are closed. A~ a reaultg the valves 14 and 23 are closed to complete the liquid ~eed stepj so that the amount of gas in the pressure reduction tower 11 is reduced to VQB as shown in Fig. 7(c).
After completion of the liquid feed step, the low pre~sure gas charge or discharge valve 20 is opened by a signal from the microcomputer 60. The high pre~sure saS in the pressure reduction tower 11 is discharged through the lines 7, 7' to outside. The pressure within the tower 11 is reduced to an inner pres~ure of the eparation tower 5. At thi~ time, an amount of gàs, ~QEP, released from the tower 11 into the line 7 is detected by the ~as flow rate detector D2 and an output si~nal from the detector D2 is sent, after A~D con~ersion, to the microcomputer 61 and the comparator 44. While the liquid le~el i9 checked by the microcomputer - 21 - ~.B '7/~/~
.
67'7.
1 . 61, the critical l evel L3 in the preceding step i~ checked ~rom a change, BB, caused by the pressure change. In this pressure reduction step, the liquid level increases from L3 to L4 whereas the amount o~ gas decreases to VQB - ~QBB a~
shown in Fi~, 7(d). It is detected from signals from the pressure detectors 32 and 33 that the pressure within the pressure reducti.on tower 11 becomes equal to.the pressure P
~ ~ 2 within the separation tower 5. After completion of ~
expansion step, a command: of opening the dischar~e valve 17 .10 is.outputted from the microcomputer 60 thereby opening the valve 17. In a subsequent liquid dîscharge step, the low pre~sure ~as is passed from the separation tower 5 to the ; pressure reduction tower 11 by an amount of VQBB + VQLL. ~t the same time, a pressure-reduced liquid is discharged from the pressure reduction tower 11 to the separation tower 5 in the same amount as the low pressure ~a9- The liquid ` level is lowered from L4 to L1. A signal corresponding to the amount of VQLL + ~QBB necessary ~or the liquid discharge is outputted from the indicator 50 according to the signal generated from the critical level setting means 35. This ~ignal is compared in the`comparator 43 with an output signal from the gas flow rate detector D2. An output signal generated from the comparator 44 when the compared si~nals agree to each other is sent -to the microcomputer 60, which ~enerates a command signal for closing the low pressure gas `
- 22 ~ k. ~. q/q ., .
67'7 1 charge or discharge val~e 2b and ~he low Pre~sure liquid discharge valve 17~ thereby closing the ~alves through the D~A converter 59 and the actuator indicator 52. This lead~
to the state o~ Fi~. 7(a).
Becau3e of the presence of solid particles in the `~ liquid which is subjected to the gas and liquid separation in the high pressure separation tower 1, there may occur -- accumulation of a precipitation in lines. Additionally, there is a fear of coking because no hydrogen is contained.
1~ This will cause a gradual increase in resistance ~f liquid flow. In order to overcom~ the above, it is necessary that heads a and b of Fig. 6 are made great and that valve and pipe diameters are also made large. However, this is disadvantageous from the standpoint of design and cost. To overcome this, there is provided, according to a still further embodiment of the invention, a pressure control valve between the high pre~sure gas and liquid separation -- tower and the high pressure gas charge or dischar~e val~e so that when a high pressure gas is transferred from the high pressure gas and liquid separation tower to the pressure ..
reduction tower, a pressure within the pressure reduction tower is set to be lower than a presYure within the separation tower. Likewise, a pressure control valve is provided between the low pressure gas charge or diqcharge valve and the low pressure gaq and liquid separation tower 50 ~ 23 -67 ~
that when a low pressure ~as is transferred From the pressure reduction tower to -the low presqure ga~ and l iquid separa t i on tower, a preqsure within the qeparation tower is set to be 1 ower than the pressure reduction tower.
This embodiment is particularly described with reference to Fig. 9.
The pre!3sUre reduction apparatus ~ of Fig. ~
includes the llne 4 havins the high pressure ga~ charge or discharge val~e 23. This l'ine 4 is branched into a feed lin,e 4a and ~ line 4b. The~ line 4~ris provided,with a first pressure control valve or F~ressure reduction valve 70 and a check valve 71 and is connected to the high pre~qure ga~ and liquid separation tower 1. The line 4b is provided with a second pressure control valve or relief valve 72 so that the gas From the high pressure gas and liquid separation tower 1 i9 discharged through a line 4c while keeping ;ts pressure energy as high as possible and a pressure within the -, pressure reduction tower 11 is set to be lower than a pressure within the separation tower 1. Because the high pressure gas in the high pressure gas and liquid separation tower 1 is also used as a`feed source for low pressure gas, the line 4b is branched to ~i~e a low pressure ~as feed line ' 4d. At the line 4d are provided a third pre~sure control valve or pressure reduction valve 73 and a stop valve 74 so that a pressure within the pressure reduction tower i1 at - 24 - k~ q/~/~
~21~6~7~
1 the time o~ liquid discharge is set to be hi~her than a pres~ure within the ~eparation tower 5. The line 4d is connected to a line 7, which i~ connected to the line 4 at one end and also to the lower pressure gas and liquid ~;s~
separation tower 5 through a-chcck valv~ 75. By the arrangement described abo~e, the liquid can be smoothly transferred from the high pressure gas and liquid separation ~ I
tower 1 to the pressure reduction tower ~ an~ al~o ~rom the tower 5 to the low pressure ~a~ and liquid separation tower by the use of pressure differences established therebetween.
In this embodiment,, the high pressure liquid feed ! ine 3 through which the high pressure liquid i~ ~ed ~rom the separation tower 1 to the pressure reduction tower 11 and the pressure-reduced liquid discharge line 6 through which the pressure-reduced liquid is fed ~rom the pressure reduction tower 11 to the low pressure gas and liquid separation tower 11 may be arran~ed in the same line as shown in Fig. 9. Additionally, the separation tower-1, the pressure reduction tower 11 and the separation tower 5 may be arranged substantially in the same level o~ space.
In operation, assuming that the liquid discharge ~`SLI~a~ 5 step has now completed, the c~ valve~ ~*~ ~5 ~
opened and a pressure P1 within the pressure reduction tower 11 is equal to a pressure P'~ within the low pressure gas and liquid separation tower 5. In thi~ state, whèn the high - 25 - ` k,Q, q/q /~
~ 7 1 pressure gas charge or discharge valve 23 is opened, the hi~h pressure gas in the qeparation tower 1 is reduced in pressure by the first pressure control valve 70, -For example, from 250kg/cm2 to 240 kg~cm2. Thi~ gas is fed through the check valve 71 and the high pressure ~as char~e or discharge vslve 23 into the pressure reduction tower 1~, by which the precssure P1 in the tower 11 increases to a level preset b~ the firqt and second pressure control valves 70 and 72. At that time, the other valves are all closed.
When the pressure P1 within the pressure reduction tower 11 reaches a preset level, thle check valve 71 is closed to complete the compre~sion or pressure elevation step.
In a subsequent liquid feed step, the liquid within the high pressure gas and liquid separation tower 1 is fed to the pressure reduction tower 11 by the difference between the pressure P'1 within the pres~ure reduction tower 11 set by the first and second pressure control valves 70, 7~ and the pressure P0 in the high pressure gas and liquid separation tower 1 ad also by the difference in head between the liquid levels of both the towers. The gas in the pressure reduction tower 11 i~ dischar~ed through the line 23 to the line 4c including the second pressure contro1 valve ~.
When the liquid is fed to the upper limit level L3 f the pressure r~duction tower 1l, the high pressure ~as - 26 - k ~ ?/q/
, . ... , . ~ .
16'7~
1 charge or aischarge valve 23 is closed and the check valve 71 is opened to complete the liquid feed step.
In a subse~uent pressure reduction step, the high pressure gas in the pressure reduction tower 11 is discharged throuqh the low pressure gas discharge line 7 including the dislcharge va;lve 75 to the low pressure gas and liquid separation tower 5. The pressure Pl within the pressure reduction tower 11 is reduced to a level of the preset pressure P'Oof the separation towe~ 5. Accordingly, the liquid in the pressure reduction tower 11 is expanded resulting in an increase of the liquid level to a level L4.
When the pressure Pl within the pressure reduction tower 11 is reduced to the preset pressure P~o within the low pressure gas and liquid separation tower S, e~g. 100 kg/cm2, the discharge valve 75 is closed to complete the pressure reduction step. When the liquid discharge valve 19 is opened and the charge valve 74 is opened, the li~uid discharge step commences.
In the liquid discharge step, the high pressure gas which is passed through the high pressure feed line 4a and the high pressure gas discharge line 4b to the low pressure gas feed line 4d acts on the liquid within the pressure reduction tower 11 as a pressure P'l set by the third pressure control valve or pressure reduction valve 73, e.g.
110 kg/cm2. Accordingly, by the pressure difference be~ween lZ1~7~
1 the set pressure P'l and the pressure Po set within the low pressure gas and li~uid separation tower 5, i.e. ~P2 = P'o - P'l, and the head differen~e between the liquid levels in both the towers, the pressure-reducea liquid is fed from the pressure reduction tower 11 to the separation tower 5. At the time when the liquid level in the pressure reduction tower 11 is dropp,ed to Ll, the charge valve 74 is closed followed hy closing the pressure-reduced li~uid discharge valve 17 thereby completing the liquid discharge step.
In the above embodiment, one pressure reduction tQWer is used but a plurality of pressure reduction towers may be connected in parallel to one another. The plurality of towers are operated in different phases of operation cycle so that the high pressure liquid is continuously discharged from the high pressure gas and liquid separation tower along with a continuously feed of pressure-reduced liquid to the low pressure gas and liquid separation tower.
As described above, at the time of feeding of liquid to the pressure reduction tower 11 and also of discharge of liquid from the tower 11, a pressure within a tower located upstream of the tower is made higher than a pressure of the downstream tower. The liquid is fed from one tower to another by the use of pressure differences ~P
and ~P2 and head differences among associated towers.
t7 1 Accordingly, upon takiny into account an increase and a decrease in liquid level within the pressure reduction tower caused by the expan~ion of liquid at the time of pres~ure redu~tion and the compres~ion of liquid at the time of pre55ure elevation, it is preferable to de~ign -the pre~ure reduction tower 11 as follow~. That is, the pre~sure reduction tower 11 is so desisned a~ to have a lensth, 1, so that its top is higher by e than a preset liquid level L5 of the high pressure gas and lliquid separation tower 1 and the bo-~tom is lower by f than Zl preset le~el L6 ~ the lower pres~ure ~as and liquid sepration tower 5. By this, the liquid level in the pressure reduction tower 11 reache~ an equilibrium at a le~el where a pressure a~ point A in the pressure reduction tower 11 becomes equal to a pressure at points BJ B' of the high and low pressure gas and liquid separation towers 1 and 5 which are at the ~ame level as the point A. Accordingly, if the pressure difference between the pre~et pressure P0 within the high pressure 3as and liquid separation tower 1 and the pressure P'1 within the pressure reduction tower 11 at the time of feed o~ liquid, i.e. ~P1 = P0 - P'1, and the difference between the pressure P~1 within the pres~ure reduction tower 11 and the preset pressure P'0 within the low pressure gas and liquid separation tower 5 at the time of liquid di~charge, i.e. a?2 = P' ~ P-1 are set accor~ing to the length~ e and f, the _ ~9 _ .
12116'77 1 liquid level does not increase over a preset level nor decrease below a preset leuel. Accordingly, the pressure reduction apparatus can be operated only by time control.
In addition, when the pressure difference~ aP1 and ~P2 are set to correspond to head los~e~ by pipes and valve~, it i~
possible that a level di~erence, c, at the time of complete of the liquid feed and a level difterence, d, at the time of completion of the liquid discharge can be made zero.
Moreover, a gas flow detector such as a difPerential pressure detector 76 is provided at the line 4 connected to the pres~ure reductio ~ At the time when the gas flow rate reaches below a certain level, the liquid level within the pressure reduction tower 11 is regarded as reaching the level L3 or L1 thereby appropriately controlling the values.
~y this, a level gauge i~ not needed for the control of the valve~. The control of the pressure reduction apparatuq .
without use of sny level gauge maY be applied to the embodiment of Fig. 6. In this case, an overall length o~
the Pressure reduction tower~is properly set similar to the 2û case of Fig. 90 A differential pre~sure detector ~lS
provided at the ga~ line ~ of Fig. 6 through which a gas is charged or discharged to the pressure reduction tower 11.
Valve control is effected in a manner similar to the above embodiment.
~ 30 - k B q~q/ 8 . .
Claims (14)
1. A pressure reduction apparatus for solid particle-containing high pressure liquids which comprises:
gas and liquid pressure reduction tower having a gas phase zone and a liquid phase zone;
a high pressure gas and liquid separation tower which has a gas phase zone connected to the gas phase zone of said gas and liquid pressure reduction tower through a first line provided with a high pressure gas charge or discharge valve, and a liquid phase zone connected to the liquid phase zone of said gas and liquid pressure reduction tower through a second line having a feed valve for liquid being reduced; and a low pressure gas and liquid separation tower which has a gas phase zone connected to the gas phase zone through a third line having a low pressure gas charge or discharge valve, and a liquid phase zone connected to the liquid phase zone through a fourth line having a valve through which a pressure reduced liquid is discharged, in which prior to opening of the Peed valve or the pressure-reduced liquid discharge valve, the high pressure gas charge or discharge valve, or the low pressure gas charge or discharge valve is opened thereby increasing or decreasing the pressure within a corresponding gas and liquid separation tower.
gas and liquid pressure reduction tower having a gas phase zone and a liquid phase zone;
a high pressure gas and liquid separation tower which has a gas phase zone connected to the gas phase zone of said gas and liquid pressure reduction tower through a first line provided with a high pressure gas charge or discharge valve, and a liquid phase zone connected to the liquid phase zone of said gas and liquid pressure reduction tower through a second line having a feed valve for liquid being reduced; and a low pressure gas and liquid separation tower which has a gas phase zone connected to the gas phase zone through a third line having a low pressure gas charge or discharge valve, and a liquid phase zone connected to the liquid phase zone through a fourth line having a valve through which a pressure reduced liquid is discharged, in which prior to opening of the Peed valve or the pressure-reduced liquid discharge valve, the high pressure gas charge or discharge valve, or the low pressure gas charge or discharge valve is opened thereby increasing or decreasing the pressure within a corresponding gas and liquid separation tower.
2. A pressure reduction apparatus according to Claim 1, further comprising a fifth line parallel to the first line and connecting said high pressure gas and liquid separation tower and said gas and liquid pressure reduction tower, the fifth line having a first expansion machine and a gas feed valve for pressure elevation, and a sixth line parallel to the second line and connecting said gas and liquid pressure reduction tower and said low pressure gas and liquid separation tower, the sixth line having an exhaust valve for pressure reduction and a second expansion machine.
3. A pressure reduction apparatus according to Claim 2, wherein the gas and liquid pressure reduction tower comprises a plurality of gas and liquid pressure reduction units connecting in parallel to one another through a plurality of gas feed valves for pressure elevation and a plurality of exhaustion valves for pressure reduction, said plurality of gas feed valves being connected to the first expansion machine in common at inlets thereof, said plurality of exhaustion valves being connected in common with the second expansion machine at outlets thereof.
4. A pressure reduction apparatus according to Claim 1, further comprising an expansion machine in a high pressure gas line branched from the first line.
5. A pressure reduction apparatus according to Claim 1, further comprising a detector means for detecting an amount of gas charged into or discharged from said gas and liquid pressure reduction tower through the high pressure gas charge or discharge valve or the low pressure gas charge or discharge valve, and a control means for controlling an amount of a liquid being reduced in pressure fed into said gas and liquid pressure reduction tower or an amount of a pressure-reduced liquid discharged from said gas and liquid pressure reduction tower on the basis of a signal from said detector means.
6. A pressure reduction apparatus according to Claim 5, wherein said gas and liquid pressure reduction tower has a pressure detector means for detecting a pressure within the pressure reduction tower, so that after a detected pressure reaches the same level as in a feed system for liquid being reduced in pressure or in a system for pressure-reduced liquid, the charge valve for liquid being reduced in pressure or the discharge valve for pressure-reduced liquid is opened.
7. A pressure reduction apparatus according to Claim 1, wherein the first line between said high pressure gas and liquid separation tower and said high pressure gas charge or discharge valve comprises a pressure control
7. A pressure reduction apparatus according to Claim 1, wherein the first line between said high pressure gas and liquid separation tower and said high pressure gas charge or discharge valve comprises a pressure control
Claim 7 continued...
valve, so that a pressure within said gas and liquid pressure reduction tower is set to be lower than a pressure within said high pressure gas and liquid separation tower by said pressure control valve.
valve, so that a pressure within said gas and liquid pressure reduction tower is set to be lower than a pressure within said high pressure gas and liquid separation tower by said pressure control valve.
8. A pressure reduction apparatus according to claim 1, wherein the second line between said low pressure gas charge or discharge valve and said low pressure gas and liquid separation tower comprises a pressure control valve, so that when a low pressure gas is fed from said gas and liquid pressure reduction tower into said low pressure gas and liquid separation tower, a pressure within said low pressure gas and liquid separation tower is lower than a pressure within said gas and liquid pressure reduction tower.
9. A pressure reduction apparatus according to claim 7, wherein said gas and liquid pressure reduction tower has a top which is higher than a set liquid level of said high pressure gas and liquid separation tower and a bottom which is lower than a set liquid level of said low pressure gas and liquid separation tower.
10. A pressure reduction apparatus according to claim 9, wherein the first line has a gas flow rate detector for detecting states of feed of the liquid being reduced in pressure and discharge of the pressure-reduced liquid whereby amounts of charge and discharge liquids are con-trolled based on an information signal detected.
11. A pressure reduction apparatus according to claim 7, 8 or 9, wherein said gas and liquid pressure reduction tower consists of a plurality of units which are connected in parallel to one another through a plurality of high pressure gas charge or discharge valves and a plurality of low pressure gas charge or discharge valves.
12. A pressure reduction apparatus according to claim 8, wherein said gas and liquid pressure reduction tower has a top which is higher than a set liquid level of said high pressure gas and liquid separation tower and a bottom which is lower than a set liquid level of said low pressure gas and liquid separation tower.
13. A pressure reduction apparatus according to claim 12, wherein the first line has a gas flow rate detector for detecting states of feed of the liquid being reduced in pressure and discharge of the pressure-reduced liquid whereby amounts of charge and discharge liquids are controlled based on an information signal detected.
14. A pressure reduction apparatus according to claim 10, 12 or 13, wherein said gas and liquid pressure reduction tower consists of a plurality of units which are connected in parallel to one another through a plurality of high pressure gas charge or discharge valves and a plurality of low pressure gas charge or discharge valves.
35.
35.
Applications Claiming Priority (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57-129164 | 1982-07-24 | ||
| JP57129164A JPS5920508A (en) | 1982-07-24 | 1982-07-24 | Power recovery device |
| JP3717083A JPS59162938A (en) | 1983-03-07 | 1983-03-07 | Control of gas-liquid decompression apparatus |
| JP57-37170 | 1983-03-07 | ||
| JP58-93245 | 1983-05-25 | ||
| JP9324583A JPS59216620A (en) | 1983-05-25 | 1983-05-25 | Method and apparatus for transferring high pressure liquid under vacuum |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1211677A true CA1211677A (en) | 1986-09-23 |
Family
ID=27289351
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000432989A Expired CA1211677A (en) | 1982-07-24 | 1983-07-22 | Pressure reduction apparatus for solid particle- containing high pressure liquids |
Country Status (3)
| Country | Link |
|---|---|
| AU (1) | AU538151B2 (en) |
| CA (1) | CA1211677A (en) |
| DE (1) | DE3326524A1 (en) |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1307533A (en) * | 1970-01-15 | 1973-02-21 | Dunlop Holdings Ltd | Pressure reducing devices |
| DE2247012C2 (en) * | 1972-09-25 | 1974-06-27 | Messer Griesheim Gmbh, 6000 Frankfurt | Device on a flame cutting machine for supplying gases |
| GB1423732A (en) * | 1973-01-25 | 1976-02-04 | Texaco Development Corp | Pressure control apparatus and method |
-
1983
- 1983-07-21 AU AU17146/83A patent/AU538151B2/en not_active Ceased
- 1983-07-22 DE DE19833326524 patent/DE3326524A1/en active Granted
- 1983-07-22 CA CA000432989A patent/CA1211677A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| AU538151B2 (en) | 1984-08-02 |
| DE3326524C2 (en) | 1987-12-10 |
| AU1714683A (en) | 1984-01-26 |
| DE3326524A1 (en) | 1984-02-09 |
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| MKEX | Expiry |