Page 179 - CW E-Magazine (22-10-2024)

Special Report

was initiated to ensure there was no continuously monitored for leaking stalled to avoid moisture ingress in sys-
other place where this material was used. phosgene. tem in case of tube-to-tubesheet joint
failure. There is provision of emergency
“To ensure that always the right The steam-ammonia curtain is a push buttons on DCS & fi eld to stop the
material is used (pipe classes, resis- secondary safety measure solution plant in case of any heavy leakage of
tant material for equipment, gaskets), which, in Covestro, is installed in phosgene gas.
a proper work/equipment quality selected areas of a limited number of
program must be in place and lived,” units in phosgene service. The purpose Several phosgene sniffers have been
Dr. Lange added. of a steam-ammonia curtain is to installed – 16 in phosgene plant, 25 in
effectively reduce any impact of released TDI plant, and 8 in outer periphery of
Secondary containment systems phosgene – by converting it to carbon other plants. Besides, 10 carbon mon-
While the primary safety measures dioxide and ammonium chloride – and oxide (CO) and 4 chlorine sniffers are
at phosgene plants are focused on pre- stop it from spreading beyond the unit installed in phosgene plant, in addition
vention and ensure that, in the very boundaries. to 12 chlorine sniffers in the chlorine-
rare event of a minor leakage, detect- handling area. “Special interlocks have
able levels of phosgene do not exceed Measures at GNFC plant been incorporated to stop the phosgene
the regulatory limits at the plant or site Mr. Hemant Yadav, Manager, plant in case of actuation of two phos-
perimeter, secondary measures, which GNFC Ltd., highlighted some of the gene sniffers at a time,” Mr. Yadav said.
are unique to the phosgene industry, safety measures taken at GNFC’s
serve to protect against the highly un- 72-tpd (tonnes per day) phosgene gas A water curtain sprinkler system has
likely event of an extensive phosgene production unit, which has no storage been installed in all fl oors of phosgene
leakage. or liquefaction facilities. The plant is plant for containment of phosgene gas in
provided with a direct connection to case of any leakages or gas released, and
In the phosgene industry three tech- emergency scrubber system in case of a provision is made to operate this water
nical options are used to limit uninten- any emergency release, and chlorine curtain sprinkler system directly from
ded emissions: containment with caustic scrubbers. Emergency and vent scrub- DCS & fi eld, as well as on actuation of
scrubber; full-jacket technology; and bers are also provided in the toluene phosgene sniffers of phosgene plant.
steam-ammonia curtain. These are used diisocyanate (TDI) plant to cater emer-
individually or in combination. gency situation. The response checking of phosgene,
chlorine, and CO sniffers, as well as
According to Mr. Joan Codina Chlorine & phosgene services have fi re-water sprinkler system are carried
Jornet, Covestro, Spain, the choice of tongue & groove type fl ange joint & out periodically.
measure is dependent, amongst other higher schedule piping with 100%
factors, on the size of the plant, the radiography tested joints of pipelines GNFC also has its own Occupa-
amount of ammonia required for a steam- for preventing leak. Specially designed, tional Health Centre with four beds and
ammonia curtain and the individual imported, high-cost Bellow seal globe three ambulances at Medical Centre
local circumstances. For new large-scale type valves are utilised in phosgene & located at plant site, in addition to a
plants, containment with caustic scrubber chlorine gas carrying pipelines, and hospital having 32 beds and two ambu-
is the method most often used and recom- double tube sheet heat exchangers in- lances located in the Township.
mended to limit damage.

The containment system includes a
ventilation system, dedicated leak de- Missed a copy !!!
tection monitors, and a caustic scrubber For Digital Edition of this month’s issue & all other past issues
system for decomposing phosgene.
Visit www.hpicindia.com
Double wall (fully jacketed) sys- PDF copies available for download
tems are the preferred secondary safety Register Now
measure for Covestro’s phosgene pro- Contact: For Subscription : Mrs. Usha S. - usha@hpicindia.com
cessing specials units, and the space For Advertising : Mr. Vijay Raghavan - vijay@hpicindia.com
between inner and outer pipe are

Chemical Weekly October 22, 2024 179

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