CA1148334A - Method and apparatus for protecting ethylene oxide, producing installations from ethylene-oxide disintegration - Google Patents
Method and apparatus for protecting ethylene oxide, producing installations from ethylene-oxide disintegrationInfo
- Publication number
- CA1148334A CA1148334A CA000340081A CA340081A CA1148334A CA 1148334 A CA1148334 A CA 1148334A CA 000340081 A CA000340081 A CA 000340081A CA 340081 A CA340081 A CA 340081A CA 1148334 A CA1148334 A CA 1148334A
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- CA
- Canada
- Prior art keywords
- ethylene oxide
- decomposition
- inert
- oxide
- ethylene
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- 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
- B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J19/0006—Controlling or regulating processes
- B01J19/002—Avoiding undesirable reactions or side-effects, e.g. avoiding explosions, or improving the yield by suppressing side-reactions
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D301/00—Preparation of oxiranes
- C07D301/32—Separation; Purification
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Epoxy Compounds (AREA)
- Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
Abstract
ABSTRACT
There is disclosed a method for protecting installations in which ethylene oxide is produced or processed, from ethylene-oxide disintegration.
Disintegration barriers are incorporated into the pipelines immediately before all large-volume containers and apparatuses, thus isolating the apparatuses from each other. In the event of a breakdown, the disintegration barriers may be cooled internally. Small-volume apparatuses and pipelines are designed to withstand pressure shock. In the event of danger, the whole installation is rendered inert, starting with the large-volume apparatuses which cannot be operated continuously in the inert condition. The use of the invention increases very considerably the operational safety of ethylene-oxide installations.
There is disclosed a method for protecting installations in which ethylene oxide is produced or processed, from ethylene-oxide disintegration.
Disintegration barriers are incorporated into the pipelines immediately before all large-volume containers and apparatuses, thus isolating the apparatuses from each other. In the event of a breakdown, the disintegration barriers may be cooled internally. Small-volume apparatuses and pipelines are designed to withstand pressure shock. In the event of danger, the whole installation is rendered inert, starting with the large-volume apparatuses which cannot be operated continuously in the inert condition. The use of the invention increases very considerably the operational safety of ethylene-oxide installations.
Description
3~
The invention relates to a method for protecting installa-tions in which ethylene oxide is produced or processed, from dis-integration or explosion of the ethylene oxide.
The purpose of the method is to increase the opera-tional safety of installations for producing and processing ethylene oxideO
The properties of ethylene oxide, such as its volatility, toxicity and its tendency to polymerize and disintegrate, make it necessary to take extensive sa~ety precautions in handling this substance.
This is taken into account in the relevant legal requirements relating to storage and transportation of ethylene oxide, in that the vapour phase is required to be rendered inert, for example by superimposing nitrogen. For technological reasons, however, these safety precautions cannot be transferred directly to installations where eth~lene oxide is produced or processed.
It is the purpose of the present invention to provide in installations in which ethylene oxide is produced and processed, protective devices which do not affec-t the operation but which protect the installation from possible ethylene-oxide disintegra-` tion According to one aspect of the invention, there is pro~ided a method for protecting ethylene oxide manufacturing and processing plants from ethylene oxide decomposition in which ; plants the gaseous ethylene oxide is in thermodynamic equilibrium ~ith liquid ethylene oxide, which comprises sectioning the plant in-to individual or several processing units by installation of flame arresters before and behind said units and upon detecting a critical operating condition which indica-tes a decomposition of ~ 1.............. .
:~ - : - .
33~
ethylene oxide~ rapidly rendering the contents of the individual or several processing units inert to the decomposition of ethylene oxide~
Another aspect of the invention provides an arrangement for protecting ethylene oxide manufacturing and processing plants from ethylene oxide decomposition in which plants gaseous ethylene oxide is in thermodynamic equilibrium with li~uid ethylene oxide, which comprises in combination with at least one apparatus for processing of ethylene oxide at least two flame arresters installed before and behind said apparatus for sectioning off said at least one processing apparatus.
Optionally, all equipment and pipelines, for which the maximal pressure arising in the event of ethylene oxide disintegrat-ion can be pre-calculated, are designed to withstand pressure shock; or the contents of individual apparatuses or groups of apparatuses, which cannot be permanently operated in the inert condition, are rapidly rendered inert in the event ~f a breakdown.
Naturally, a combination of these functionally matching precautions can be Pmployed.
Special preference is given to the combination of all three of these precautions, since this provides comprehensive pro-tection which has considerable advantages as compared with the present state of the art.
The propagation of an ethylene~oxide disintegration is p~evented by isolating individual apparatuses or groups of appara-tuses. This is achie~ed by the provision of "flame arrestors" or "disintegration barriers" and these terms are used interchangeably herein. Suitable distintegration barriers, include embankments of filler materials, such as are used in handling acetylene. More-over, individual apparatuses (for instance the distilling unit), if suitably designed, may themselves act as disintegration barriers.
The flow through disintegration barriers in -the form of filler-material embankments should preferably be vertical, in order to avoid large unobstructed channels in the direction of flow.
Disintegration barriers o~ the design mentioned abo-~e are always capable of arresting an incipient ethylene~oxide aisinte-gration. If, however, operational conditions exist (e.g. high operating pressures) which allow a stationary disintegxation flame to form ahead of the barrier, then the life of the barxier is limited, due to the increasing heat. In ~hese cases, therefore, the area behind the barrier, i.e. the content of the apparatus to be protected r must be inert or must be rendered inert within the time a~ailable.
The life o~ a disintegration barrier may be extended at will if suitable action is taken, for instance by internal spray-ing with water, the spray density being sufficient to ensure that the fill~r material does not become unduly hot.
~11 apparatuses and pipelines, for which the maximal pressure occurring during ethylene-oxide disintegration can be pre-calculated with sufficient accuracy, are designed to withstand pressure shock. The expression "designed to withstand pressure shock" implies that, in the event of a pressure shock, a component may be loaded brie~ly up to the yield point of the material from which it is made. This design is sensible since, in the event of ethylene-oxide disintegration, it prevents destruction of the com-- 2a -~3 .
.
.
.
3~
ponent and possible decompression of the installation.
Designing the apparatuses and pipelines to withstand pressure shock is desirable if the increase in preasure d~ing ethylene~oxide disinte~ration is limited. It has been ~ound by tests tha-t, in the event of ethylene-oxide disintegration, in the a~sence o~ -the liquid pha~e, the ~inal pressure aoes not exceed about 10 times the initial value. Howe~er, in the case oP appa-ratuses ~hich contain large quanti-ties o~ the liquid phase in additi~n to the vapour phase ~ the distillation columng ~or instance - a maximal final pres sure cannot be calculated since some o~ the liquid co-reacts. It is precisely in this kind of equipmen+. that rapid inerting is o~ critical significance.
Large pieces o~ equipment which canno-t be kept constantly in the inert condition, e.g. the distillation column~ are rapidly rendered inert as soon as operating conditions become crîtical. This is a necessary precaution to prevent ethylene oxide disintegration being initiat.ed b~ s~r~ercritically heated container walls~ pipe walls, and disintegration barriers.
Individual apparatuses~ or groups o~ apparatuses, may be rendered inert by the introduction o~ a suitable gas~ pre~erably nitrogen. In the "column-condenser" system the gas may be introduced simultaneously at several locations suitably matched in respect of opening times and amounts o~ gas introduced. An in~rt state may be achieved in a partic~arly simple manner if the gas is introduced a~ove the sump only. If the nitroeen is correctly metered-in, this renders the column, the condenser~ and the vapour pipe inert and pre~ents the ~ormation of areas of critical ethylene-oxide concentration.
r~he entire s~stem is inert if the ethylene-oxide vapour concentration does not exceed, at any point, a value of about 50% by volume. The nitrogen re-quired is preferably stored under pressure in a separate tank.
The distilling column used to separate a mixture of water and ethylene oxide may also be rendered inert without introducing a suitable gas, ~ .
namely by the water-vapour which rises when the val~es in the ~eed and return lines are closed.
Equipment may be rendered inert with gases other than nitrogen a for instance carbon dioxide, noble gases, saturated gaseous hydrocarbons or olefines.
Since equipment can be rendered inert, as a precauti~n, ~nly after a critical operating condition has been dete~ed, monitoring and the recog-nition of ~uch a critical condition, by suitable process parameters, becomes a matter of considerable significance. ~he following ~actors, among o-thers, have been found to be sui-table monitoring criteria~ the temperature in the disintegration barriers, the pressure in large-volume apparatuses, and the concentration of ethylene oxide in the air in the vicinity of units which ha~e been fo~d by experience to be sub~ect to leakage.
Disintegration barriers have hitherto been used in acetylene irl-stallations, i.e. a gas having a tendency to disintegrate, the temperature o~
which lies, under plant operating condition~, sufficiently above its con-den~ation temperature. Disintegration barriers have hitherto been regarded as effective only in the absence of the liquid phase o~ the substance in question.
However, during the distilling o~ ethylene oxide, the gaseous and liquid phases thereo~ are in thermoaynamic equilibrium; the ~iller material in the dlsintegration barriers is usually wetted by the boiling liquid phase.
It has been shown, however, by extensive experimental inves-tiga-tion, that disinteeration barriers of conventional design~ ~rhich are mois-tened or sprayed with the liquid phas,e of the substance capable oP dis-integrating, have an excellent barrier effect. Such tests are preferably ~ carried out with fillings made of 15 mm diameter "Pall" rings, the said fil-; lings being about 152 m in length and about 9 cm in diameter. Disintegration ;
-:
, 33~
barriers ~lade wi-th other components having a similar specific surface are similarly e~fecti~e. This unexpected result thus overcomes existing prej-udices against the use of disintegration barriers in the presence of vapours tending to disintegrate, i.e. where the rillings are moistened or sprayed with the liquid phase.
The dimensions o~ disin-te~ration barriers, suitable for the pro-tection of installation producing and processing ethylene oxide, may be determined as follows:
The height of the disintegration barriers depends upon the time required to render inert -the large-volume containers ana app~ratuses which are isolated by the said barriers, in the event of a breakdown, and upon the life tz of the said barriers. The latter is determined by the specific sur face of the embankments and the conditions for stability in the event of a breakdown. In order to prevent propagation of the disintegration into the large-volume containers isolated by the disintegration barriers, t~ must be ; greater than ti.
~ he life o~ the disintegr~tion barriers is the time taken by the flame front to pierce the embankment; it is proportional to the height H of the barriers and inversely proportional to the average velocity of propaga-tion vz of the flame front in -the filling of the barrier:
tz = H
Vz As a result of this:
tz = H = S and ti Vz ti Safety factor S must be greater than l; generally S > 1.2, and ." .
preferably S = 1.5.
In disintegration barriers which are filled with "Pall." rings 15 mm in diameter and made of V4A refined steel~ the average ~ of propaga-tion vz of the flame front of disintegrating ethylene oxide is between 1 and 4 cm/s, ~here there is no internal water-cooling of the filling, with a pres-sure in excess of 15 bars in the installation. If the p~essure is less than 15 bars, the ~lame front no longer spreads through the barrier. This veloc-ity of propa.gation may be reduced still further by internal cooling of the filling.
A filling of "Pall" rings measuring 15 x 15 x 0.4 m~ and made of V4A re~ined steel, compacted by shaking to a bulk weight of between 500 and 530 kg/m3, has a speci.fic surface of between 350 and 370 m /m3. If dis-integration barriers with other materials are used in ethylene-oxide insta.l-lations, the specific surface must be in this range or above.
The cross-sect.ion of the disintegration barriers is determined by the coefficient o~ resistance of the filling and by the pressure drop, at the normal pressure obtained in the installation, in the gas or vapour flowing through the barrier: :
Qp = ~ Vj 2 wherein:
a is the permissible pressure drop at the disintegration P barrier under normal operating conditions;
~ is the coefficient o~ resistance of the filling;
: H is the height of the disintegration barrier;
dp is a "characteristic dimension" of the filling;
g is the density o~ the gas under operating conditions;
V iB the a.verage volume-~low of gas through the disintegration :~ ' ~ , ~
3~
barrier; and F is the cross-section of the disin~eg-ration barrier.
In the case of a filling o~ "Pall" rings measuring 15 x 15 x 0.4 mm and made of V~A refined stecl:
= 3.5 to 5.5 d = 1.5 cm.
P
The following emerges from this for ~he cross-section of the disintegra~ion barrier:
F = V / p ~ . H
/ 2~ d ~ ' \/ P p The accompanying drawing illustrates the use of di.s-integration barriers and an arrangement for rendering khe equip-ment inert, using as an example a distilling column for a m1xture of liquids, with ethylene oxide as the lower-boiling component.
~he ethylene-oxide-containing liquid to be distilled reaches dis*illing column 2 through a supply line 1. The high-boiling component is removed as a sump-product through line 3 . The as-, . .
cending ethylene-oxide vapo~lr passes through line 4 to condenser 5, where it is condensed, and is then collected in receiver 6.
Uncondensed components are gated out, through pressure-maintaining valve 7 within line 8. ~iquid ethylene oxide is removed from the receiver by p~lmp 9, through line 10, and returned to the head of the column, or it may pass through line 11 for further processing.
The nitrogen required to render the equipment inert is stored in pressure tank 12.
: ;~ ., `' , .: ,, .
:
f~ 3~
The distilling column is protected from an incoming ethylene-oxide disintegration by the incorporation of disinte-gration barriers 20 to 23 in -the feed-line, vapour-line, return line and sump-product-line. The same applies to the condenser, which is protected by barriers 24 and 25 in the - 7a -.... . .. . .
.
! .
.
: ~ ' . .
. .
. " ' .
vapour and inert-~as lines, and by ~eceiver 6 which is designed as a dis-integratiorl barrier.
In the event of a critical operating condition, valves 30, 31, 32, 33 and 7 are closed, the supply o~ vapour to circulating evaporator 35 is shut off - if necessary after a del.ay by valve 31;, and valves 36 and 38 release nitrogen into the column, where~y the said column and condenser are rendered inert.
The invention relates to a method for protecting installa-tions in which ethylene oxide is produced or processed, from dis-integration or explosion of the ethylene oxide.
The purpose of the method is to increase the opera-tional safety of installations for producing and processing ethylene oxideO
The properties of ethylene oxide, such as its volatility, toxicity and its tendency to polymerize and disintegrate, make it necessary to take extensive sa~ety precautions in handling this substance.
This is taken into account in the relevant legal requirements relating to storage and transportation of ethylene oxide, in that the vapour phase is required to be rendered inert, for example by superimposing nitrogen. For technological reasons, however, these safety precautions cannot be transferred directly to installations where eth~lene oxide is produced or processed.
It is the purpose of the present invention to provide in installations in which ethylene oxide is produced and processed, protective devices which do not affec-t the operation but which protect the installation from possible ethylene-oxide disintegra-` tion According to one aspect of the invention, there is pro~ided a method for protecting ethylene oxide manufacturing and processing plants from ethylene oxide decomposition in which ; plants the gaseous ethylene oxide is in thermodynamic equilibrium ~ith liquid ethylene oxide, which comprises sectioning the plant in-to individual or several processing units by installation of flame arresters before and behind said units and upon detecting a critical operating condition which indica-tes a decomposition of ~ 1.............. .
:~ - : - .
33~
ethylene oxide~ rapidly rendering the contents of the individual or several processing units inert to the decomposition of ethylene oxide~
Another aspect of the invention provides an arrangement for protecting ethylene oxide manufacturing and processing plants from ethylene oxide decomposition in which plants gaseous ethylene oxide is in thermodynamic equilibrium with li~uid ethylene oxide, which comprises in combination with at least one apparatus for processing of ethylene oxide at least two flame arresters installed before and behind said apparatus for sectioning off said at least one processing apparatus.
Optionally, all equipment and pipelines, for which the maximal pressure arising in the event of ethylene oxide disintegrat-ion can be pre-calculated, are designed to withstand pressure shock; or the contents of individual apparatuses or groups of apparatuses, which cannot be permanently operated in the inert condition, are rapidly rendered inert in the event ~f a breakdown.
Naturally, a combination of these functionally matching precautions can be Pmployed.
Special preference is given to the combination of all three of these precautions, since this provides comprehensive pro-tection which has considerable advantages as compared with the present state of the art.
The propagation of an ethylene~oxide disintegration is p~evented by isolating individual apparatuses or groups of appara-tuses. This is achie~ed by the provision of "flame arrestors" or "disintegration barriers" and these terms are used interchangeably herein. Suitable distintegration barriers, include embankments of filler materials, such as are used in handling acetylene. More-over, individual apparatuses (for instance the distilling unit), if suitably designed, may themselves act as disintegration barriers.
The flow through disintegration barriers in -the form of filler-material embankments should preferably be vertical, in order to avoid large unobstructed channels in the direction of flow.
Disintegration barriers o~ the design mentioned abo-~e are always capable of arresting an incipient ethylene~oxide aisinte-gration. If, however, operational conditions exist (e.g. high operating pressures) which allow a stationary disintegxation flame to form ahead of the barrier, then the life of the barxier is limited, due to the increasing heat. In ~hese cases, therefore, the area behind the barrier, i.e. the content of the apparatus to be protected r must be inert or must be rendered inert within the time a~ailable.
The life o~ a disintegration barrier may be extended at will if suitable action is taken, for instance by internal spray-ing with water, the spray density being sufficient to ensure that the fill~r material does not become unduly hot.
~11 apparatuses and pipelines, for which the maximal pressure occurring during ethylene-oxide disintegration can be pre-calculated with sufficient accuracy, are designed to withstand pressure shock. The expression "designed to withstand pressure shock" implies that, in the event of a pressure shock, a component may be loaded brie~ly up to the yield point of the material from which it is made. This design is sensible since, in the event of ethylene-oxide disintegration, it prevents destruction of the com-- 2a -~3 .
.
.
.
3~
ponent and possible decompression of the installation.
Designing the apparatuses and pipelines to withstand pressure shock is desirable if the increase in preasure d~ing ethylene~oxide disinte~ration is limited. It has been ~ound by tests tha-t, in the event of ethylene-oxide disintegration, in the a~sence o~ -the liquid pha~e, the ~inal pressure aoes not exceed about 10 times the initial value. Howe~er, in the case oP appa-ratuses ~hich contain large quanti-ties o~ the liquid phase in additi~n to the vapour phase ~ the distillation columng ~or instance - a maximal final pres sure cannot be calculated since some o~ the liquid co-reacts. It is precisely in this kind of equipmen+. that rapid inerting is o~ critical significance.
Large pieces o~ equipment which canno-t be kept constantly in the inert condition, e.g. the distillation column~ are rapidly rendered inert as soon as operating conditions become crîtical. This is a necessary precaution to prevent ethylene oxide disintegration being initiat.ed b~ s~r~ercritically heated container walls~ pipe walls, and disintegration barriers.
Individual apparatuses~ or groups o~ apparatuses, may be rendered inert by the introduction o~ a suitable gas~ pre~erably nitrogen. In the "column-condenser" system the gas may be introduced simultaneously at several locations suitably matched in respect of opening times and amounts o~ gas introduced. An in~rt state may be achieved in a partic~arly simple manner if the gas is introduced a~ove the sump only. If the nitroeen is correctly metered-in, this renders the column, the condenser~ and the vapour pipe inert and pre~ents the ~ormation of areas of critical ethylene-oxide concentration.
r~he entire s~stem is inert if the ethylene-oxide vapour concentration does not exceed, at any point, a value of about 50% by volume. The nitrogen re-quired is preferably stored under pressure in a separate tank.
The distilling column used to separate a mixture of water and ethylene oxide may also be rendered inert without introducing a suitable gas, ~ .
namely by the water-vapour which rises when the val~es in the ~eed and return lines are closed.
Equipment may be rendered inert with gases other than nitrogen a for instance carbon dioxide, noble gases, saturated gaseous hydrocarbons or olefines.
Since equipment can be rendered inert, as a precauti~n, ~nly after a critical operating condition has been dete~ed, monitoring and the recog-nition of ~uch a critical condition, by suitable process parameters, becomes a matter of considerable significance. ~he following ~actors, among o-thers, have been found to be sui-table monitoring criteria~ the temperature in the disintegration barriers, the pressure in large-volume apparatuses, and the concentration of ethylene oxide in the air in the vicinity of units which ha~e been fo~d by experience to be sub~ect to leakage.
Disintegration barriers have hitherto been used in acetylene irl-stallations, i.e. a gas having a tendency to disintegrate, the temperature o~
which lies, under plant operating condition~, sufficiently above its con-den~ation temperature. Disintegration barriers have hitherto been regarded as effective only in the absence of the liquid phase o~ the substance in question.
However, during the distilling o~ ethylene oxide, the gaseous and liquid phases thereo~ are in thermoaynamic equilibrium; the ~iller material in the dlsintegration barriers is usually wetted by the boiling liquid phase.
It has been shown, however, by extensive experimental inves-tiga-tion, that disinteeration barriers of conventional design~ ~rhich are mois-tened or sprayed with the liquid phas,e of the substance capable oP dis-integrating, have an excellent barrier effect. Such tests are preferably ~ carried out with fillings made of 15 mm diameter "Pall" rings, the said fil-; lings being about 152 m in length and about 9 cm in diameter. Disintegration ;
-:
, 33~
barriers ~lade wi-th other components having a similar specific surface are similarly e~fecti~e. This unexpected result thus overcomes existing prej-udices against the use of disintegration barriers in the presence of vapours tending to disintegrate, i.e. where the rillings are moistened or sprayed with the liquid phase.
The dimensions o~ disin-te~ration barriers, suitable for the pro-tection of installation producing and processing ethylene oxide, may be determined as follows:
The height of the disintegration barriers depends upon the time required to render inert -the large-volume containers ana app~ratuses which are isolated by the said barriers, in the event of a breakdown, and upon the life tz of the said barriers. The latter is determined by the specific sur face of the embankments and the conditions for stability in the event of a breakdown. In order to prevent propagation of the disintegration into the large-volume containers isolated by the disintegration barriers, t~ must be ; greater than ti.
~ he life o~ the disintegr~tion barriers is the time taken by the flame front to pierce the embankment; it is proportional to the height H of the barriers and inversely proportional to the average velocity of propaga-tion vz of the flame front in -the filling of the barrier:
tz = H
Vz As a result of this:
tz = H = S and ti Vz ti Safety factor S must be greater than l; generally S > 1.2, and ." .
preferably S = 1.5.
In disintegration barriers which are filled with "Pall." rings 15 mm in diameter and made of V4A refined steel~ the average ~ of propaga-tion vz of the flame front of disintegrating ethylene oxide is between 1 and 4 cm/s, ~here there is no internal water-cooling of the filling, with a pres-sure in excess of 15 bars in the installation. If the p~essure is less than 15 bars, the ~lame front no longer spreads through the barrier. This veloc-ity of propa.gation may be reduced still further by internal cooling of the filling.
A filling of "Pall" rings measuring 15 x 15 x 0.4 m~ and made of V4A re~ined steel, compacted by shaking to a bulk weight of between 500 and 530 kg/m3, has a speci.fic surface of between 350 and 370 m /m3. If dis-integration barriers with other materials are used in ethylene-oxide insta.l-lations, the specific surface must be in this range or above.
The cross-sect.ion of the disintegration barriers is determined by the coefficient o~ resistance of the filling and by the pressure drop, at the normal pressure obtained in the installation, in the gas or vapour flowing through the barrier: :
Qp = ~ Vj 2 wherein:
a is the permissible pressure drop at the disintegration P barrier under normal operating conditions;
~ is the coefficient o~ resistance of the filling;
: H is the height of the disintegration barrier;
dp is a "characteristic dimension" of the filling;
g is the density o~ the gas under operating conditions;
V iB the a.verage volume-~low of gas through the disintegration :~ ' ~ , ~
3~
barrier; and F is the cross-section of the disin~eg-ration barrier.
In the case of a filling o~ "Pall" rings measuring 15 x 15 x 0.4 mm and made of V~A refined stecl:
= 3.5 to 5.5 d = 1.5 cm.
P
The following emerges from this for ~he cross-section of the disintegra~ion barrier:
F = V / p ~ . H
/ 2~ d ~ ' \/ P p The accompanying drawing illustrates the use of di.s-integration barriers and an arrangement for rendering khe equip-ment inert, using as an example a distilling column for a m1xture of liquids, with ethylene oxide as the lower-boiling component.
~he ethylene-oxide-containing liquid to be distilled reaches dis*illing column 2 through a supply line 1. The high-boiling component is removed as a sump-product through line 3 . The as-, . .
cending ethylene-oxide vapo~lr passes through line 4 to condenser 5, where it is condensed, and is then collected in receiver 6.
Uncondensed components are gated out, through pressure-maintaining valve 7 within line 8. ~iquid ethylene oxide is removed from the receiver by p~lmp 9, through line 10, and returned to the head of the column, or it may pass through line 11 for further processing.
The nitrogen required to render the equipment inert is stored in pressure tank 12.
: ;~ ., `' , .: ,, .
:
f~ 3~
The distilling column is protected from an incoming ethylene-oxide disintegration by the incorporation of disinte-gration barriers 20 to 23 in -the feed-line, vapour-line, return line and sump-product-line. The same applies to the condenser, which is protected by barriers 24 and 25 in the - 7a -.... . .. . .
.
! .
.
: ~ ' . .
. .
. " ' .
vapour and inert-~as lines, and by ~eceiver 6 which is designed as a dis-integratiorl barrier.
In the event of a critical operating condition, valves 30, 31, 32, 33 and 7 are closed, the supply o~ vapour to circulating evaporator 35 is shut off - if necessary after a del.ay by valve 31;, and valves 36 and 38 release nitrogen into the column, where~y the said column and condenser are rendered inert.
Claims (10)
1. A method for protecting ethylene oxide manufacturing and processing plants from ethylene oxide decomposition in which plants the gaseous ethylene oxide is in thermo-dynamic equilibrium with liquid ethylene oxide, which comprises sectioning the plant into individual or several processing units by installation of flame arresters before and behind said units and upon detecting a critical operating condition which indicates a decomposition of ethylene oxide, rapidly rendering the contents of the individual or several processing units inert to the decomposition of ethylene oxide.
2. A method according to claim 1, wherein all apparatus and ducts for which the maximum pressure resulting from ethylene oxide decomposition can be precalculated with a sufficiently high degree of reliability are designed to withstand pressure shock.
3. A method for protecting ethylene oxide manufacturing and processing plants from ethylene oxide decomposition in which plants gaseous ethylene oxide is in thermo-dynamic equilibrium with liquid ethylene oxide, which comprises sectioning the plant into individual or several processing units by installation of flame arresters before and behind said units, utilizing apparatus and ducts, for which the maximum pressure resulting from ethylene oxide decomposition can be precalculated with a sufficiently high degree of reliability, that are designed to withstand pressure shock, and upon detecting a critical operating condition which indicates a decomposition of ethylene oxide, rapidly rendering inert the contents of the individual or several processing units which cannot constantly be held inert during continued normal operation.
4. A method according to claim 1, 2 or 3 which further comprisesutilizing individual units which are constructed to be effective as flame arresters.
5. A method according to claim 1 or 3 which further comprises internal cooling of the flame arresters during a critical operating condition by injecting a cooling fluid into the flame arresters.
6. A method according to claim 1, 2 or 3 wherein a distillation column for separation of a mixture of water and ethylene oxide is used 7 said column is rendered inert by closing valves in the inlet to the column and in the reflux line and by utilizing the rising vapor of water within said column whereby said column is rendered inert.
7. An arrangement for protecting ethylene oxide manufacturing and processing plants from ethylene oxide decomposition in which plants gaseous ethylene oxide is in thermo-dynamic equilibrium with liquid ethylene oxide, which comprises in combination with at least one apparatus for processing of ethylene oxide at least two flame arresters installed before and behind said apparatus for sectioning off said at least one processing apparatus.
8. An arrangement according to claim 7 wherein further all apparatus and ducts for which the maximum pressure resulting from ethylene oxide decomposition can be precalculated with a sufficiently high degree of reliability are designed to withstand pressure shock.
9. An arrangement according to claim 7 which further comprises a pressure tank for storing a gas for rendering the at least one apparatus inert to decomposition of ethylene oxide and means for injecting said gas into said at least one processing apparatus.
10. An arrangement according to claim 7, wherein the flame arrestors have a height:
H = S . vz . ti and a cross section:
wherein:
S = a safety factor ? 1.2 vz = the average velocity of propagation of the flame front in the flame arrestor; in the case of disintegrating ethyl-ene-oxide, vz is between 1 and 4 cm/s, without internal cooling, and at an operating pressure of above 15 bar ti = the time required to render inert large-volume containers ? = the average volume-flow of the gas ? = the density of the gas under operating conditions .DELTA.p = the admissible pressure drop at the flame arrestor under normal operating conditions ? = the coefficient of resistance of the filling dp = the characteristic dimension of the filling.
H = S . vz . ti and a cross section:
wherein:
S = a safety factor ? 1.2 vz = the average velocity of propagation of the flame front in the flame arrestor; in the case of disintegrating ethyl-ene-oxide, vz is between 1 and 4 cm/s, without internal cooling, and at an operating pressure of above 15 bar ti = the time required to render inert large-volume containers ? = the average volume-flow of the gas ? = the density of the gas under operating conditions .DELTA.p = the admissible pressure drop at the flame arrestor under normal operating conditions ? = the coefficient of resistance of the filling dp = the characteristic dimension of the filling.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP2850254.7-42 | 1978-11-20 | ||
| DE19782850254 DE2850254C2 (en) | 1978-11-20 | 1978-11-20 | Methods and devices for the protection of plants producing and processing ethylene oxide from decomposition of ethylene oxide vapor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1148334A true CA1148334A (en) | 1983-06-21 |
Family
ID=6055128
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000340081A Expired CA1148334A (en) | 1978-11-20 | 1979-11-19 | Method and apparatus for protecting ethylene oxide, producing installations from ethylene-oxide disintegration |
Country Status (12)
| Country | Link |
|---|---|
| EP (1) | EP0011126B2 (en) |
| JP (1) | JPS55108863A (en) |
| AT (1) | AT374192B (en) |
| AU (1) | AU531880B2 (en) |
| BR (1) | BR7907475A (en) |
| CA (1) | CA1148334A (en) |
| DD (1) | DD147238A1 (en) |
| DE (1) | DE2850254C2 (en) |
| EG (1) | EG14778A (en) |
| ES (1) | ES486121A1 (en) |
| SU (1) | SU1118288A3 (en) |
| TR (1) | TR21415A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4982861A (en) * | 1987-09-21 | 1991-01-08 | Akzo N.V. | Explosion-safe liquid container |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19542829A1 (en) * | 1995-11-17 | 1997-05-22 | Basf Ag | Process for the distillation of ethylene oxide |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CH179586A (en) * | 1935-02-26 | 1935-09-15 | Hoffmann Rudi Ing Dipl | Protection against explosion transmission. |
| FR1492999A (en) * | 1966-07-11 | 1967-08-25 | Aquitaine Petrole | Inhibition of thermal oxidation of hydrocarbons |
| US3557243A (en) * | 1968-02-23 | 1971-01-19 | Monsanto Co | Automatic independently functioning sparging apparatus |
| US3628758A (en) * | 1969-07-22 | 1971-12-21 | Parker Hannifin Corp | Fuel tank inerting system |
| FR2258884A2 (en) * | 1972-02-02 | 1975-08-22 | Boehler & Co Ag Geb | Safety device for two-stage flash evaporator - protecting against press. loss in the second stage |
| DE2452803A1 (en) * | 1974-11-07 | 1976-05-20 | Basf Ag | Hydrocarbon oxidation, esp. direct oxidation of propylene - with reaction controlled by oxygen concn. analyser |
| JPS5824234B2 (en) * | 1977-12-05 | 1983-05-19 | 山田油機製造株式会社 | Hammer motor |
-
1978
- 1978-11-20 DE DE19782850254 patent/DE2850254C2/en not_active Expired
-
1979
- 1979-10-08 EP EP19790103836 patent/EP0011126B2/en not_active Expired
- 1979-11-16 DD DD21696179A patent/DD147238A1/en unknown
- 1979-11-19 CA CA000340081A patent/CA1148334A/en not_active Expired
- 1979-11-19 ES ES486121A patent/ES486121A1/en not_active Expired
- 1979-11-19 AT AT734579A patent/AT374192B/en not_active IP Right Cessation
- 1979-11-19 EG EG68679A patent/EG14778A/en active
- 1979-11-19 AU AU52958/79A patent/AU531880B2/en not_active Ceased
- 1979-11-19 BR BR7907475A patent/BR7907475A/en unknown
- 1979-11-19 TR TR2141579A patent/TR21415A/en unknown
- 1979-11-20 JP JP14963779A patent/JPS55108863A/en active Pending
-
1981
- 1981-11-24 SU SU813358561A patent/SU1118288A3/en active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4982861A (en) * | 1987-09-21 | 1991-01-08 | Akzo N.V. | Explosion-safe liquid container |
Also Published As
| Publication number | Publication date |
|---|---|
| SU1118288A3 (en) | 1984-10-07 |
| EG14778A (en) | 1985-03-31 |
| AU5295879A (en) | 1980-05-29 |
| EP0011126A3 (en) | 1980-06-25 |
| EP0011126A2 (en) | 1980-05-28 |
| DD147238A1 (en) | 1981-03-25 |
| DE2850254A1 (en) | 1980-05-22 |
| EP0011126B1 (en) | 1982-02-24 |
| ATA734579A (en) | 1983-08-15 |
| JPS55108863A (en) | 1980-08-21 |
| AT374192B (en) | 1984-03-26 |
| BR7907475A (en) | 1980-08-05 |
| ES486121A1 (en) | 1980-10-01 |
| TR21415A (en) | 1984-05-03 |
| DE2850254C2 (en) | 1982-03-11 |
| AU531880B2 (en) | 1983-09-08 |
| EP0011126B2 (en) | 1986-04-30 |
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