US3598146A

US3598146A - Electrical first-out indicator system for use with pneumatic controls on a petroleum process

Info

Publication number: US3598146A
Authority: US
Inventors: Allen M Robin; Dale R Jesse
Original assignee: Texaco Inc
Current assignee: Texaco Inc
Priority date: 1969-09-29
Filing date: 1969-09-29
Publication date: 1971-08-10
Anticipated expiration: 1988-08-10

Abstract

An electrical indicator system is connected to a petroleum process where pneumatic controls are employed and where automatic shutdown will take place if any one of a plurality of parameters exceeds predetermined limits. The electrical system uses relays that are actuated by the pneumatic controls which indicate when a parameter goes outside limits. Each such relay has interlocking contacts with the circuits for all the other relays, so that the first actuated relay will lock out the remaining relays. This provides an indication of which condition was first outside limits.

Description

U Umted States Patent [72] Inventors Allen M. Robin 5 Refe n e Cited Anaheim; UNITED STATES PATENTS gm?" Jess" bah 2,600,132 6/1952 Seaton 340/2132 [2H APPL No. L762 2,701,872 2/1955 Marmorstone... 340/415 X [22] Filed Sept 29 1969 3,117,303 1/1964 Byme 340/415 X [45! Paemed Aug 10 1971 3,144,046 8/1964 Seesse1berg.. 137/552 X [73] Assign Tam Inc. 3,461,444 8/1969 Eisele 340/332 New York, N.Y. Primary Examiner-Henry T. Klinksiek Attorneysl E. Kavanagh and Thomas H. Whaley [54] ABSTRACT: An electrical indicator system is connected to a PETROLEUM PROCESS petroleum process where pneumatic controls are employed and where automatic shutdown will take place if any one of a 6 Chums 3 Drawmg Figs plurality of parameters exceeds predetermined limits. The [52] U.S.Cl 137/552, electrical system uses relays that are actuated by the pneu- 137/554, 340/415 matic controls which indicate when a parameter goes outside [51] Int. Cl ..Fl6k 37/00, limits. Each such relay has interlocking contacts with the cirl-l04q 3/02 cuits for all the other relays, so that the first actuated relay will [50] Field of Search 137/552 lock out the remaining relays. This provides an indication of which condition was first outside limits.

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention concerns a petroleum process that has pneumatic controls and particularly relates to an electrical system connected to act with the pneumatic controls ofthe petroleum process for providing first-out indication when the petroleum process is shut down by reason of some one of the various parameters exceeding predetermined limits.

2. Description of the Prior Art In petroleum processes in general and in particular with respect to a synthesis gas generating process, it is quite common to have the process controlled pneumatically. Also, it is well known to provide an arrangement such that automatic shutdown of the system will take place if any of a given number of parameters in the process should exceed predetermined limits. This is to prevent catastrophic failure and possible loss of valuable equipment.

However, when such a shutdown occurs it may be very difficult and time consuming to determine the cause. One reason for this is that as shutdown takes place, all of the parameters will exceed limits. Therefore, it would be a great help and time saver to be able to have an indication of which was the first of the parameters to exceed its limits, after an automatic shutdown has taken place.

Pneumatic control instruments have been designed in such a way to give a first-out" indication when shutdown occurs. However, such instruments involve the use of more expensive and complicated pneumatic equipment, which alsorequires higher pneumatic pressures than are normally employed in the control systems to which this invention applies. Furthermore, some pneumatic firstout" systems have been constructed in such a way that a malfunction of one of the pneumatic relays could activate the automatic shutdown system even though the process is operating nonnally.

SUMMARY OF THE INVENTION Briefly, the invention relates to a synthesis-gas-generating process or the like, wherein a plurality of parameters are monitored and the process includes means for shutting down said process if any of said parameters exceeds predetermined limits. Related to the foregoing, there is an electrical system for indicating the first of said parameters to exceed said limits. The system comprises means for connecting a source of power to said system, and a first switch responsive to each of said parameters and actuated when the parameter exceeds said limit. The system also comprises a relay corresponding to each of said parameters and each relay having g plurality of simultaneously actuated contacts thereon providing second separate switches, one corresponding to each of said other parameters. The system also comprises circuit means for connecting one of said second switches between said source of power and each of said other relays.

Again briefly, the invention relates to the combination with a refinery process or the like having pneumatic control and monitoring instruments. The process includes at least some pneumatically controlled valves for shutting down the process. It also includes a plurality of condition monitors which provide pneumatic signals indicative of said conditions, and a plurality of pneumatic control instruments actuated by said pneumatic signals. It also includes pneumatic means for automatically actuating said valves when any one of said conditions exceeds predetermined limits. In combination with the foregoing refinery process there is an electrical system for indicating which of said conditions is the first to exceed said limits, and such electrical system comprises means for connecting a source of electric power to said system. It also comprises a first switch actuated by each of said pnuematic control instruments, and a relay corresponding to each of said condition monitors and said relay having a plurality of contacts providing second separate switches one corresponding to each condition except for that corresponding to the said relay. It also comprises circuit means for connecting one of said second switches between said source of electric power and each of the other of said relays.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing and other objects and benefits of the invention will be more fully set forth below in connection with the best mode contemplated by the inventor of carrying out the invention, and in connection with which there are illustrations provided in the drawings, wherein:

FIG. I is a circuit diagram illustrating a simplified form of electrical system according to the invention;

FIG. 2 is an across-the-line type electrical circuit diagram which illustrates a somewhat more complicated system as it is applied to a synthesis gas generation process; and

FIG. 3 is a schematic flow diagram illustrating a synthesisgas-generation process including an indication of some of the connection points for an electrical first-out indicator system of the type shown in FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The basic concept of the invention, as it pertains to an electrical system for providing first-out indication which relates to a petroleum process, is illustrated in FIG. 1. The process may have a plurality of parameters that are being measured and/or monitored. And, the electrical first-out indicator system has a corresponding relay for each of these parameters,

In FIG.] there are shown four relays that are marked R-I, R-Z, R-3, and R-4. The four relays each have a coil I I, I2, I3 and 14 respectively. Each coil actuates a group of four-double throw switches, as indicated. There is respectively a mechanical connection for each which is schematically indicated by a dashed line l7, 18, I9 and 20 respectively.

In order to have each of the four parameters cause actuation of one of the relays under predetermined conditions, there is a corresponding pressure actuated

switch

26, 27, 28 and 29, one for each of the four relays R-l, R-2, R-3 and R-4, respectively. The pneumatic system of the petroleum process is arranged so that the parameters will actuate the pressure switches 26-29 when the parameters exceed the predetermined limits. Actuation of any one of the pressure switches will close the contacts of that switch and consequently complete a circuit to energize the corresponding one of the relay coils Il-l4. As soon as that happens, the contacts of that relay will be switched to the other position from that illustrated and consequently the circuit to all of the remaining three relay coils will be broken. This will thus prevent energization of those relays and consequently whichever relay is energized gives an indication that the corresponding parameter was the first to exceed its limits.

It will be appreciated and explained more fully below that the addition of some other circuits may be provided without changing the basic concept of the invention. Also, it may be noted here that the first-out indication is provided by an indicator light 32 corresponding to relay R-1 and similarly lights 33, 34 and 35 corresponding to relays R2, R-3, and R-4 respectively. These lights will be energized or illuminated when the corresponding relay is actuated. Of course only the first to be energized or illuminated will be that corresponding to the first-out indication, since the other contacts of that relay will remove the other relays from possible energization.

The basic system includes a switch 38 for energizing the whole system. There are a pair of terminals 39 for connecting a source of electrical energy to the system.

To illustrate the operation of FIG. I it may be assumed that the system switch 38 is closed. Then assuming that the first parameter to go outside limits is the one that actuates the pressure switch. 26 it will be closed and it will energize coil II of relay R-I.

Such energizing circuit may be traced from the other side of switch 38, i.e., away from the terminal 39, over a circuit connection 42. The circuit continues from there over a conductor 43, and another conductor 44 to a junction point 45. It then continues to one side, or contact, of the pressure switch 26. From the other side of switch 26, it continues over a connection 48 to one side of a switch 49 of the group actuated by relay R4. Then it goes via a connection 50 and a switch 52 to another connection 51. The circuit continues over a switch 53 to a circuit connection 56 that goes to one end of the relay coil 11. The other end of the coil 11 is connected via a circuit connection 57 to another circuit connection 58 that leads to a junction point 59. From junction Q there is a circuit connection 60 leading to the other input terminal 39 for the electrical energization of the system.

When the relay Rl is energized, its contacts will be switched over from the position illustrated to the other position for all of the four switch blades shown. Consequently, a switch 61 is opened and likewise a switch 62 as well as a third switch 64. Each of these switches is connected in the energizing circuit for one of the other relays R4, R2 and R3 respectively so that none of them can be energized after the relay R-] has been energized.

There is an indicator-light circuit to energize one of the indicator lights which correspond to the relays. This needs no explanation, it being sufficient to note by way of example that when the relay Rl is energized a switch 63 is closed and completes a circuit for energizating light 32.

FIGS. 2 and 3 system Some of the benefits of a first-out indicator system have been mentioned above. A particular embodiment will now be described which illustrates an application of such a system to a petroleum process. In this case the process is a synthesis gas generator unit which is schematically illustrated in FIG. 3. There are four operating parameters that can initiate a shutdown of the operation. These are indicated by the captions at the upper-left-hand position of FIG. 3. They are labeled Quench Level, Oxygen," Process Water or Carrier Gas" and Oil." However, the electrical system shown in FIG. 2 provides for a total of seven parameter-controlled shutdown points, but the principles of the operation do not change.

In addition to the foregoing first-out shutdown indication points, there is a manual shutdown indicator. Also there is a timer for determining the exact time when a shutdown occurs.

The automatic shutdown circuit is armed from the pressure in the generator of the foregoing process. However, the details of such a shutdown system with this equipment and circuits, is not necessary for an understanding of this invention. Such a shutdown system is important to prevent catastrophic failures and possible loss of valuable equipment. In the past when a shutdown has occurred there has been difficulty and often much time lost in making a determination as to the exact cause of the shutdown. Therefore, when a first-out electrical indicator system according to this invention is employed, any such time loss is avoided. Furthermore, as already indicated, a timing indicator may be provided so that the exact time when the first-out malfunction took place, may also be noted.

It will be observed that the FIG. 2 circuit diagram employs a different convention from that of the circuit diagram of FIG. 1. Thus, in FIG. 2 there are parallel circuits shown from one side of a source of electrical supply to the other which would be connected to a pair of terminals 65. The showings for switch contacts are not like those of FIG. I, but are such that the symbol of two parallel lines crossed by a sloping line, indicates switch (or relay) contacts that are closed when the relay is deenergized. On the other hand, the symbol of two parallel lines without any crossed sloping line, indicated switch (or relay) contacts that are closed when the relay (to which these contacts belong) is energized. Which contacts belong to which relays is made clear by the captions with capital letter designations.

The relays are designated in the diagram as R" followed by a number. This designation is placed adjacent to both the contact symbols and the circular symbols that represent the coil, or coils, contacts each relay. Furthermore, because of the number of relay contacts employed with each of the seven relays that correspond to parameters of the petroleum process, there are twin relays used at each of these corresponding parameter-relay stations. Consequently, such relay coils are designated by the captions including the letters A and B. However, no letter designations are employed with the contacts.

It will be appreciated that each of the foregoing seven relays, and corresponding circuits, are substantially the same. Therefore, the FIG. 2 diagram does not show all seven, but merely the first two and the seventh of the whole group.

The operation of the FIG. 2 system will be clear from an understanding of the description of the FIG. I circuit, in general. However, with specific reference to FIG. 2, it may be noted that there is a pressure switch 66 which is designated by the caption PS-l. This is under control of the parameter that happens to correspond with this relay. The switch 66 will be closed if that parameter goes outside of its predetermined limits. Closing of switch 66 will complete a circuit that will energize both relay coils 67 and 68. These have the captions R-IA and R-IB respectively. The circuit is completed through relay contacts R2, R3, R4, R5, R6, and R7 which all stand as indicated in the diagram by a single reference number 69. At the same time, an indicator light 72 (designated Ll) will be energized.

It will be observed that the FIG. 2 system adds electrical holding circuits. This acts to keep the first relay pair and its indicator light energized until the whole system has been reset following he shutdown conditions. Thus, in the Rl relay circuit described above there is a pair of contacts 70 that are captioned with the designation RI. These contacts 70 will close when the relay Rl (coils 67 and 68) is actuated. The closing of these contacts completes a holding circuit across the pres sure switch 66 and the other relay contacts R2, R3, R4, RS, R-6 and R7 so that irrespective of whether any individual conditions should return within limits, the first-out indicator will hold its original indication.

It will be appreciated, of course, that there is a normally closed set of contacts 71 in each of the other relay circuits, e.g., R2R7. These are all opened when the relay R1 is actu ated. They act to cut off the possible later actuation of any of the other relays.

As another example, assume that another parameter, i.e., that which actuates a pressure switch 74 (designated PS-Z) is the first to exceed limits. Switch 74 will be closed and the circuit for relay R2 will be completed from one side of the power source through all of the contacts that stand closed, i.e., contacts 75 (designated Rl, R3, R-4, R5, R6 and R7). This will energize relay coils for the second relay, i.e., a coil 76 and a coil 77. Also, the indicator light 78 (designated L-2) will be energized. Energization of the relay R-2 will actuate the contacts designated R2. This includes contacts 80 that are located in each of the other groups of normally closed contacts. In addition, contacts 81 that are normally open (when relay is deenergized) will be actuated to close the holding circuit.

There is a timer circuit which includes a pressure switch 84 (designated PS-8) that is closed when the system has developed sufficient pressure to activate the above-mentioned automatic shutdown. The switch 84 is in series with a timer 85 that will be energized and will run following startup of the process, until a shutdown occurs.

There is provided a manual shutdown indicator that is in addition to the first-out shutdown indicator system described above. There are two additional relays (RIO) and 94 (RI I one additional pressure switch 93 (PS-9) and also an indicator light 95 (L9) plus a pushbutton switch 96 (SW9).

The operation of the manual shutdown may be described as follows with reference to FIG. 2. With the Generator" (FIG. 3) operating, all of the parameter controlled pressure switches (PS-I through RS7) and switch 93 (PS-9) are open. while switch 84 (PS-8) is closed. The timer 85 is operating, while a time-delay relay 91 (R8) is energized and a relay 92 (R-9) is deenergized. All the contacts except for contacts 97 (R8), are in the position indicated by the symbols employed.

Asuming a manual shutdown is initiated, the pressure switch 93 (PS-9) will close. This energizes the relay 94 (R-II) and the indicator light 95. Once energized they are locked on through contacts 99 (R-l I) and contacts 100 (R-9). At the same time contacts 101 (R41) are opened which renders it impossible to energize any of the parameter relays R-I through R-7 regardless of the position of the corresponding pressure switches PS-I-PS7. Also, contacts 89 (R-Il) in the timer circuit are opened and the timer is stopped.

Now when the "Generator (FIG. 3) is brought on stream again, the manual shutdown switch 93 (PS-9) will be open. Consequently, the relay 94 (R-II will be deenergized when the relay 92 (R-9) is momentarily energized during startup, since the contacts 100(R-9) will be opened.

If we assume a shutdown was caused by one of the parameter-controlled pressure switches PS1PS7, it will energize its relay-and-alarm light. It will also stop the timer 85 and deenergize the relay 90 (R-l0) in the timer circuit because of the opening of the corresponding one of the contacts in a group of contacts 88. Therefore, contacts 98 (R-) will be opened and will prevent the relay 94 (R-I l) and the indicator light 95 from being energized regardless of the position of the manual shutdown switch 93 (PS-9).

It will be observed that there are momentary contact-type pushbutton switches captioned Test." Also, there is a toggle switch 104 that controls power to the electrical system. By manipulating these in an expected manner the alarm lights and relays may alarm checked. However, it is to be noted that because one alann circuit will always be locked in alarm status if the Generator" (FIG. 3) is off line and power is applied to the electrical system, there is provided an arrangement to automatically clear such circuit. The arrangement involves the relay 92 (R9) and the time-delay relay 9! (R8).

The sequence of events in the operation of the foregoing arrangement is as (R- 8) With power an and the Generator" (FIG. 3) 011' stream, the relays 91 (R-8) and 92 (R-9) are deenergized and contacts 105 (R-9) are closed. This permits current to flow to the alarm circuits (parameter controlled). As the Generator (FIG. 3) is brought on stream, the switch 84 (PS-8) is closed and this energizes the time-delay relay 91 (11-8) which closes the contacts 97 (ll-8) for the duration of the time-delay period. This energizes the relay 92 (R-9) for that length of time and opens the contacts 105 which deenergizes all of the alarm relay circuits. After the time delay period, the contacts 97 (R-8) are opened which deenergizes the relay 92 (R-9) and closes the contacts 105 restoring power to the alarm circuits. Since the Generator" (FIG. 3) is then on stream none of the indicator (alarm) lights will be lit.

FIG 3 is clearly self-explanatory and it is pointed out that the various symbols employed are explained by appropriate legends. The process illustrated is a synthesis gas generator and four of the parameters are indicated by the captions Quench Level, Oxygen," Process Water or Carrier Gas" and Oil." Each of these conditions in the system is monitored by the pneumatic system in the manner indicated. This includes pressure controllers 107, I08, 109 and 110. These are pneumatic instruments that are snap acting and allow either 0 or maximum instrument air pressure to be applied to the output. In each case the-output is connected to the diaphragm of a corresponding valve as illustrated. It will be observed also that the inputs to the controllers are taken from an appropriate monitoring instrument in each case, e.g., the oxygen flow is monitored by a flow transmitter 117 connected to an orifice 118, as indicated.

As shown by the square symbols marked FO," there is a pneumatic-connection point in the system of FIG. 3 where each pressure switch (e.g., switch 74 of FIG. 2) is connected. For example, a connection point 111, I12, I13 and 114 is indicated to? each of the four captioned parameters, respective? It will be appreciated that a system according to this invention may be employed with other and different process having automatic shutdown which might have more or less parameters to be monitored.

While the foregoing embodiments of the invention have been described in considerable detail in accordance with the applicable statutes, this is not to be taken as in any way limiting the invention, but merely as being descriptive thereof.

1 claim:

1. In a synthesis-gas-generating process, or the like, wherein a plurality of parameters are monitored and including means for shutting down said process if any of said parameters exceeds predetermined limits,

an electrical system for indicating the first of said parameters to exceed said limits, comprising means for connecting a source of power to said system,

a first switch responsive to each of said parameters and actuated when the parameter exceeds said limit,

a relay corresponding to each of said parameters and each relay having a plurality of simultaneously actuated contacts thereon providing second-separate switches, one corresponding to each of said other parameters, and

circuit means for connecting one of said second switches between said source of power and each of said other relays.

2. The invention according to claim 1 wherein said first switches are closed when actuated, and

wherein said second-separate switches are opened when the relays associated therewith is actuated whereby one of the other relays can be activated thereafter.

3. The invention according to claim 2 further including a third switch on each of said relays, and

second circuit means for connecting said third switch in a holding circuit for retaining actuation of the actuated relay even after the said parameter has returned within said limits.

4. In combination with a refinery process or the like having pneumatic control and monitoring instruments, and including at least some pneumatically controlled valves for shutting down the process,

said process also including a plurality of condition monitors which provide pneumatic signals indicative of said conditions,

a plurality of pneumatic control instruments actuated by said pneumatic signals, and

pneumatic means for automatically actuating said valve when any one of said conditions exceeds predetermined limits,

the combination of an electrical system for indicating which of said conditions is the first to exceed said limit, comprising means for connecting a source of electric power pneumaticcontrol said system,

a first switch actuated by each of said pneumatic-control instruments,

a relay corresponding to each of said condition monitors and said relay having a plurality of contacts providing second-separate switches, one corresponding to each condition except for that corresponding to the said relay, and

circuit means for connecting one of said second switches between said source of electric power and each of the other of said relays.

5. The invention according to claim 4 wherein said first switches are closed when said control instruments are actuated, and

wherein said second switches are opened when the relay associated therewith is actuated whereby none of the other relays can be actuated thereafter.

6. The invention according to claim 5 furtherincluding a third switch on each of said relays, and

a second circuit means for connecting said third switch in a holding circuit for retaining actuation of the actuated relay even after the said condition has returned within said limits.

* g;;g UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,598,146 Dated August 10, 1971 Inventor(g) ALLEN M. ROBIN and DALE R. JESSE It is certified that error appears in the above-identified patent and that: said Letters Patent are hereby corrected as shown below:

Column 3, line 48, "with this equipment" should read with its equipment Column 4, line 74, "RS-7" should read Ps-7 Claim 1, line 12, "second-separate" should not be hyphenated Claim 2, line 3, "second-separate" should not be hyphenated Claim 2, line 4, "whereby one of" should read whereby none of Claim 4, line 10, "said valve" should read said valves Claim 4, lines 16 'power pneumatic-control said" should and 17 read power to said Claim 4, line 22, "second-separate" should not be hyphenated Sig-nod and sealed this 18th day of April 1972.

ISEAL) ittest:

GD'z-IARD I LI LETCIILEELJR. ROBERT GOT'ISCHALK [testing Officer Commissioner of Patents

Claims

1. In a synthesis-gas-generating process, or the like, wherein a plurality of parameters are monitored and including means for shutting down said process if any of said parameters exceeds predetermined limits, an electrical system for indicating the first of said parameters to exceed said limits, comprising means for connecting a source of power to said system, a first switch responsive to each of said parameters and actuated when the parameter exceeds said limit, a relay corresponding to each of said parameters and each relay having a plurality of simultaneously actuated contacts thereon providing second-separate switches, one corresponding to each of said other parameters, and circuit means for connecting one of said second switches between said source of power and each of said other relays.

2. The iNvention according to claim 1 wherein said first switches are closed when actuated, and wherein said second-separate switches are opened when the relays associated therewith is actuated whereby one of the other relays can be activated thereafter.

3. The invention according to claim 2 further including a third switch on each of said relays, and second circuit means for connecting said third switch in a holding circuit for retaining actuation of the actuated relay even after the said parameter has returned within said limits.

4. In combination with a refinery process or the like having pneumatic control and monitoring instruments, and including at least some pneumatically controlled valves for shutting down the process, said process also including a plurality of condition monitors which provide pneumatic signals indicative of said conditions, a plurality of pneumatic control instruments actuated by said pneumatic signals, and pneumatic means for automatically actuating said valve when any one of said conditions exceeds predetermined limits, the combination of an electrical system for indicating which of said conditions is the first to exceed said limit, comprising means for connecting a source of electric power to said system, a first switch actuated by each of said pneumatic-control instruments, a relay corresponding to each of said condition monitors and said relay having a plurality of contacts providing second-separate switches, one corresponding to each condition except for that corresponding to the said relay, and circuit means for connecting one of said second switches between said source of electric power and each of the other of said relays.

5. The invention according to claim 4 wherein said first switches are closed when said control instruments are actuated, and wherein said second switches are opened when the relay associated therewith is actuated whereby none of the other relays can be actuated thereafter.

6. The invention according to claim 5 further including a third switch on each of said relays, and a second circuit means for connecting said third switch in a holding circuit for retaining actuation of the actuated relay even after the said condition has returned within said limits.