1. weyer special | safety valves weyer group
allround. smart.
SAFETY VALVES www.weyer-group.com

2. weyer special | safety valves
Safety valves
A key safety aspect when engineering process plants is the efficient prevention of impermissibly high overpressures in
the process systems when malfunctions occur. In many cases, this can only be ensured by installing safety valves or
general mechanical pressure relief devices. The weyer group has had extensive experience in the dimensioning of safety
valves, as well as of the downstream systems required to divert and dispose of the substances produced. The entire range
of services in terms of selecting and designing or recalculating these systems, is briefly described in the following.
What we offer: 1 Determination of blow- • Fire in the vicinity of the plant
 Determination of blow- down cases In the course of determining the blow-
down cases, the extent to which alterna-
When determining the blow-down cases,
down cases tive measures can be effectively taken to
we examine which malfunctions during
 Selection and dimen- prevent those impermissible pressure in-
plant operation can lead to impermissible
creases, can also be examined. Alternative
sioning or recalculation pressure increases in the system. These
measures to be used in this context could
examinations are often performed in con-
of pressure relief devices be, for example, instrumentation & control
junction with or based on a safety study
 Selection and design of systems.
(e.g., HAZOP or PAAG).
downstream systems  Possible causes that can lead to a
 Complete support blow-down are, for example:
• Faulty closing or opening of valves
(automatic / manual)
• Faulty control / defective measur-
ing systems
• Pipe rupture in heat exchangers
• Failure of utilities (e.g., power,
cooling water, auxiliary energy for
valves)
weyer special | safety valves | page 2

3. weyer group
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2 Selection and dimensio- 3 Selection and design of 4 Complete support
ning or recalculation of downstream systems Apart from the calculation, all further
pressure relief devices The substance mixtures to be discharged planning steps in the course of the pro-
can often not be exhausted into the atmo- curement, installation or replacement of
Based on the blow-down cases deter-
sphere untreated, but must be conducted safety valves can then be performed by
mined, appropriate pressure relief devices
to a suitable treatment system. In the ma- the weyer group.
are selected and dimensioned. An impor-
tant aspect during design is taking into
account any two-phase flows that may
occur. These can occur in plants in which,
during normal operation, two-phase mix-
tures are handled or if, in the case of a
blow-down, fluids are entrained with es-
caping gases and vapors.
When dimensioning the pressure relief
devices, particularly for two-phase flows,
jority of cases, the installation of a flare-
gas network with knock-out drum and
flare is the method chosen. To design Your benefits:
these networks, the weyer group uses a
variety of rigorous simulation programs,  xclusion of organizational responsi-
E
including one developed by the weyer bility
group itself.
 etermination of the relevant blow-
D
current national and international stan- down cases
dards e.g., DIN EN ISO 4126 , API 520 /
521, AD 2000) are taken into account. The  election and dimensioning / recalcu-
S
weyer group has developed its own calcu- lation of pressure relief devices
lation system for this.
Finally, the actual pressure losses in the  niform
U documentation, indepen-
feed and discharge lines are calculated. In dently of the plant constructor or sup-
the case of recalculations, if necessary, a pliers of the pressure relief devices
survey of the pipelines / pipeline networks
is performed on site.  election and design of downstream
S
systems
Normally, the substance data required for
the calculation is obtained by using
process simulators.
weyer special | safety valves | page 3

4. weyer group
allround. smart.
Your contact
www.weyer-group.com
The weyer group is a group-independent corporate association of engineering and con-
sulting companies in Germany, Austria and Switzerland.
Since its establishment over 30 years ago, the weyer group has developed a wide range of
expertise which has always been based on the expectations and wishes of our clients.
References:
 Boehringer Ingelheim Pharma GmbH Co.KG
 DHC Solvent Chemie GmbH
 Mineraloelraffinerie Oberrhein GmbH Co.KG
 PCK Raffinerie GmbH
 Shell Deutschland Oil GmbH
 Vopak Dupeg Terminal Hamburg GmbH
 Wilhelmshavener Raffineriegesellschaft mbH
Illustrations with friendly permission obtained
through LESER GmbH Co. KG Hamburg
www.weyer-group.com