U.S. patent application number 16/777057 was filed with the patent office on 2020-07-30 for trailer and method for transporting peracetic acid.
This patent application is currently assigned to PEROXYCHEM LLC. The applicant listed for this patent is PEROXYCHEM LLC. Invention is credited to James Brennan, John M. Rovison, JR..
Application Number | 20200238887 16/777057 |
Document ID | 20200238887 / US20200238887 |
Family ID | 1000004752166 |
Filed Date | 2020-07-30 |
Patent Application | download [pdf] |
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United States Patent
Application |
20200238887 |
Kind Code |
A1 |
Rovison, JR.; John M. ; et
al. |
July 30, 2020 |
TRAILER AND METHOD FOR TRANSPORTING PERACETIC ACID
Abstract
A trailer for transporting a liquid mixture having at least
about 5% peracetic acid by weight includes a stainless steel tank
having an external spill containment enclosure and a predetermined
maximum allowable working pressure. One or more pressure relief
valves are included in a wall of the tank within the external spill
containment enclosure and configured to provide pressure relief to
the tank at a pressure of between about 20%-50% of the maximum
working pressure of the tank, thereby preventing
over-pressurization of a reactive and decomposing fluid during a
fire event. Wheels and a kingpin are affixed to the tank to enable
transportation over public roadways.
Inventors: |
Rovison, JR.; John M.;
(Sanborn, NY) ; Brennan; James; (Williamsville,
NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
PEROXYCHEM LLC |
Philadelphia |
PA |
US |
|
|
Assignee: |
PEROXYCHEM LLC
Philadelphia
PA
|
Family ID: |
1000004752166 |
Appl. No.: |
16/777057 |
Filed: |
January 30, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
16125204 |
Sep 7, 2018 |
10625655 |
|
|
16777057 |
|
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|
14019696 |
Sep 6, 2013 |
10086743 |
|
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16125204 |
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61726297 |
Nov 14, 2012 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B60P 3/225 20130101;
B60P 3/2255 20130101 |
International
Class: |
B60P 3/22 20060101
B60P003/22 |
Claims
1. A method for transporting a liquid mixture having at least about
5% peracetic acid by weight, the method comprising: filling a
trailer with peracetic acid, the trailer comprising: a stainless
steel tank having an external spill containment enclosure and a
predetermined maximum allowable working pressure; and one or more
pressure relief valves included in a wall of the tank within the
external spill enclosure, wherein the one or more pressure relief
valves are configured to provide pressure relief to the tank at a
pressure of less than about 50% of the maximum working pressure of
the tank; and transporting the trailer over a roadway using wheels
and a kingpin affixed to the tank.
2. The method of claim 1, wherein the maximum allowable working
pressure is about 40 psig.
3. The method of claim 1, wherein the one or more pressure relief
valves are configured to provide pressure relief when a pressure
inside the tank exceeds about 10 psig.
4. The method of claim 3, wherein the one or more pressure relief
valves have combined relief area greater or equal to 11.94
in.sup.2.
5. The method of claim 1, wherein a relief area of the one or more
pressure relief valves are configured to prevent internal pressure
within the tank from exceeding a maximum pressure during a
decomposition event or fire engulfment.
6. The method of claim 1, wherein the one or more pressure relief
valves includes two 4'' diameter pressure relief valves, each
configured to provide pressure relief to the tank at about 10
psig.
7. The method of claim 1, wherein the one or more pressure relief
valves are reclosing pressure relief valves.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation of U.S. application Ser.
No. 16/125,204, filed Sep. 7, 2018, which is a Divisional of U.S.
application Ser. No. 14/019,696, filed Sep. 6, 2013, now patented
as U.S. Pat. No. 10,086,743, which claims the benefit of the filing
date of U.S. Provisional Application No. 61/726,297, which was
filed Nov. 14, 2012. The entire content of these applications is
hereby incorporated by reference herein.
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0002] The field of the present invention is vessels used for and
methods of transporting peracetic acid.
2. Background
[0003] Hazardous materials in the liquid state are often
transported in stainless steel containers, particularly 316
stainless, because stainless steel is inert to many such hazardous
materials. The Department of Transportation (DOT) regulates all
such shipments to ensure public roadway safety, and the type of
regulatory restrictions vary depending upon the hazardous nature of
the liquid being transported.
[0004] For example, 49 C.F.R. 173.225 sets forth packaging
requirements for organic peroxides, and indicates that a DOT-412
cargo tank may be used for transporting certain organic peroxides.
The DOT-412 cargo tank has a nominal capacity of 5000 gallons, and
is constructed according to the requirements set forth in 37 CFR
178.320, 178.345, and 178.348, the design specifications of which
are incorporated herein by reference in their entirety. However,
the DOT-412 cargo tank is not authorized for transporting peracetic
acid, as this Type F organic peroxide, ID No. UN 3109 (as listed in
37 C.F.R. 172.101) is limited to a bulk containers having a
capacity of up to 1,500 liters (396 gallons).
[0005] Requirements for the DOT-412 cargo tank include a 316
stainless steel container having a maximum allowable working
pressure (MAWP) of not more than 40 psig and a resealable pressure
relief system. According to regulations, the pressure relief system
on a DOT-412 cargo tank is to have a set pressure to provide
pressure relief at between 120%-132% of the MAWP and a minimum
venting capacity based upon the exposed area of the cargo tank,
which is typically provided by one 3'' reclosing pressure relief
valve. The intent of these regulations is to equip the DOT-412
cargo tank with a sufficient size and quantity of pressure relief
devices so that an increase in pressure of the cargo tank, whether
due to a self-accelerating decomposition or fire engulfment, would
not result in a rupture of the cargo tank.
[0006] The DOT can make exceptions to the regulations for the
transport of hazardous materials over public roadways on a
case-by-case basis. As one example, Azko Nobel Polymer Chemicals,
LLC, of Chicago, Ill., has obtained an exemption for the transport
of two types of Type F liquid organic peroxides, ID Nos. UN3109 and
UN3119, both in Packing Group II, in a modified DOT-412 cargo tank.
The modifications leading to approval of this special permit by the
DOT include installation of six 12'' diameter non-reclosing
pressure relief devices (in the form of rupture discs) as a single
unit without being installed in series with a reclosing pressure
relief device.
[0007] Due to the hazardous nature of the organic peroxide subject
to the Azko exemption, which is more reactive than peracetic acid,
which is also a Type F liquid organic peroxide, ID No. UN3109,
Packing Group II, and the increased risk of decomposition event if
transferred in a standard DOT-412 cargo tank, the solution arrived
at for the Azko special permit was to increase the overall pressure
relief area to about 340 in.sup.2. Although peracetic acid would
not likely require as much pressure relief area as specified in the
Azko special permit, a significantly large pressure relief area
would be required. In view of the large pressure relief area
required, a different solution has been sought for a cargo tank to
transport peracetic acid, one which could also be implemented by
modifying a DOT-412 cargo tank, and one which would also meet the
DOT goals of having pressure relief devices of a sufficient size
and quantity so that an increase in pressure of the cargo tank,
whether due to a self-accelerating decomposition or fire
engulfment, would not result in a rupture of the cargo tank.
SUMMARY OF THE INVENTION
[0008] The present invention is directed toward a trailer and a
method or design tactic for transporting a liquid mixture having at
least about 5% peracetic acid by weight. A stainless steel tank has
an external spill containment enclosure and a predetermined maximum
allowable working pressure. Wheels and a kingpin are affixed to the
tank. One or more pressure relief valves are included in the wall
of the tank within the spill containment enclosure, wherein the one
or more pressure relief valves are configured to provide pressure
relief to the tank at a pressure of between about 20%-50% of the
maximum allowable working pressure of the tank. Preferably, the
pressure relief valves are configured to prevent internal pressure
within the tank from exceeding a maximum pressure during a
decomposition event or fire engulfment, thereby preventing
over-pressurization of a reactive and decomposing fluid during a
fire event. The pressure relief valves may have a pressure relief
area greater or equal to 11.94 in.sup.2, and they may be configured
to provide pressure relief when a pressure inside the tank exceeds
about 10 psig. Other combinations of set pressures and pressure
relief areas may also be used. With such a trailer provided, the
tank may be filled with a liquid mixture having at least about 5%
peracetic acid by weight and transported over public roadways.
[0009] Accordingly, an improved trailer and method for transporting
peracetic acid are disclosed. Advantages of the improvements will
be apparent from the drawings and the description of the preferred
embodiment.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] In the drawings, wherein like reference numerals refer to
similar components:
[0011] FIG. 1 illustrates a trailer configured to transport
peracetic acid;
[0012] FIG. 2 illustrates pressure relief valves for the trailer of
FIG. 1;
[0013] FIG. 3 illustrates additional valves and returns for the
trailer of FIG. 1;
[0014] FIG. 4 is a partial top elevation view of the trailer of
FIG. 1; and
[0015] FIG. 5 is a rear view of the trailer of FIG. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0016] Turning in detail to the drawings, FIG. 1 illustrates a
trailer 100 configured for transporting a liquid mixture (shown
implicitly inside the tank) having at least about 5% peracetic acid
by weight. Although many different concentrations of peracetic acid
may be transported using the trailer, the ensuing description will
discuss the trailer in the context of transporting UN3109, nominal
15% peracetic acid/10% hydrogen peroxide (referred to as PAA
below), which is a liquid organic peroxide of Type F, in Product
Group II.
[0017] The trailer 100 has a stainless steel tank 102, to which is
affixed dual axels 104 and associated wheels 106, and a kingpin 108
for securing the trailer 100 to a motorized rig (not shown) for
transportation over public roadways. Except for the modifications
described below, the trailer is constructed in conformance with the
DOT-412 cargo tank requirements of set forth in 37 CFR 178.320,
178.345, and 178.348. Thus, the trailer may be constructed new with
modifications to the manufacturing specifications, or it may be
constructed by modifying an existing DOT-412 cargo tank. Following
are the modifications made to an existing DOT-412 cargo tank to
obtain the trailer 100 depicted in the figures.
[0018] The existing pressure relief valve (or rupture disk on older
cargo tanks) of a standard DOT-412 cargo tank is removed, as is the
ceramic breather vent. Two recloseable 4'' diameter pressure relief
valves 110 are installed in the side wall of the tank 102, as shown
in FIG. 2. The two pressure relief valves 110 preferably conform
with applicable DOT requirements under 37 CFR 178.345, and they
have set pressure of 10 psig. They also provide a total pressure
relief area of 13.65 in.sup.2. An external spill containment
enclosure 112 is placed on the outside of the tank 102 around the
two pressure relief valves 110. This enclosure 112 prevents release
of PAA onto the roadway in the event the pressure relief valves 110
activate in transit. Moreover, the combination of the pressure
relief valves 110 and the enclosure 112 are anticipated to
significantly contain discharge of PAA into the environment, even
in the event of a rollover, thereby preventing over-pressurization
of a reactive and decomposing fluid during a fire event. The
enclosure 112 may also include internal splash baffles (not shown)
to minimize PAA entrainment if/when the pressure relief valves 110
activate.
[0019] It has been determined that with PAA in a transport
container, the internal pressure of the container will generally be
in the range of about 5 psig to 10 psig during transit. The 10 psig
set pressure of the pressure relief valve, or valves, is therefore
sufficient to prevent PAA leakage during normal transport
conditions. Further, through experimentation, it has been
determined that with a set pressure of 10 psig, a total pressure
relief area of 11.94 in.sup.2 is sufficient to prevent internal
pressure within the tank from exceeding the maximum tank pressure
during a decomposition event or fire engulfment. Specifically, for
PAA, the self-accelerating decomposition temperature in a DOT-412
cargo tank has been calculated to be 61.degree. C. Liquids with
lower amounts of peracetic acid are anticipated to have a higher
self-accelerating decomposition temperature. With the two
recloseable 4'' diameter pressure relief valves 110 installed, it
has been calculated that tank pressurization would be limited to no
more than 42.2 psig during a decomposition event or fire
engulfment.
[0020] At a set pressure of 44 psig, the calculated pressure relief
area is 20.5 in.sup.2 for PAA in a DOT-412 cargo tank. Although
calculations of pressure relief area have not been performed for
other set pressures, it is anticipated that the relationship
between set pressure and pressure relief area is somewhat close to
being linear for PAA in a DOT-412 cargo tank. Therefore, even with
these two data points (10 psig, 44 psig), the calculations show
that PAA can be contained, and internal pressure within the tank
can be prevented from exceeding the maximum pressure of the tank
during a decomposition event or fire engulfment, even when pressure
relief valves having a pressure of 50% or less of the MWAP of the
tank are used.
[0021] A quick connect coupling 114 and a valve 116 are added to
the tank 102 within the enclosure 112, as shown in FIG. 3, along
with a vapor return 118. The quick connect coupling 114 and the
valve 116 enable the tank to be filled with PAA, and the vapor
return 118 provides a vapor outlet from a storage tank into which
the PAA is unloaded.
[0022] The tank 102 is also fitted with a manual bleed-off valve
120 within the enclosure 112, as shown in FIGS. 3 & 4. This
bleed-off valve 120 enables the internal tank pressure to be vented
prior to offloading. In addition, the bleed-off valve 120 may be
equipped with a suitable capture device to minimize operator
exposure to PAA fumes when the tank is vented.
[0023] Gauges (not shown in the figures) to monitor the internal
pressure, temperature, and level of the tank should be added to the
trailer. The first two gauges enable the operator to monitor the
internal pressure and temperature of the tank during transit, and
the level gauge allows the operator to determine when loading and
unloading operations are completed, since due to the hazardous
nature of PAA, visual inspection of the tank is not an option.
[0024] As shown in FIG. 5, a valve 122 is installed at the top of
the dip pipe 124, through which PAA is drawn by the unloading pump
not shown. A second spill containment enclosure 126 may be
constructed about the valve 122 at the rear of the trailer. A small
pressure relief valve (not shown) may also be installed immediately
upstream of the valve 122 to prevent PAA from being trapped during
unloading, and a locking vented dust cap (not shown) may be
installed at the discharge of the unloading pump. These additions
to the inlet and discharge of the unloading pump, while optional,
are intended to provide additional protection against siphoning of
PAA through the trailer discharge line during transit, in the event
that the valve 122 is left open or fails in the open position.
[0025] Finally, the discharge of the existing siphon break (not
shown) on the unloading line is routed back to vapor space within
the tank to prevent release of PAA into the environment in the
event the siphon valve is left open.
[0026] By making the above modifications to the standard DOT-412
cargo tank, it is anticipated that PAA may be transported safely in
greater quantities than the presently-allowed 1,500 liters (396
gallons) maximum. The transport of greater quantities would allow
greater demands for PAA to be met. For example, PAA is being used
increasingly as a microbial control agent by direct applications on
meats, in asceptic packaging, and in oil and gas field
applications. The bulk transportation of PAA also means less
handling of the hazardous material during filling, transportation,
and offloading. Finally, it is anticipated that the proposed
modified DOT-412 cargo tank would be as safe, or safer, than
containers which meet current regulations.
[0027] Thus, a trailer and method for transporting peracetic acid
are disclosed. While embodiments of this invention have been shown
and described, it will be apparent to those skilled in the art that
many more modifications are possible without departing from the
inventive concepts herein. The invention, therefore, is not to be
restricted except in the spirit of the following claims.
* * * * *