Expanding Simplot’s Rock Springs
phosphoric acid plant in Wyoming
Simplot Phosphates’ Rock Springs facility is a major producer of granular mono-ammonium
phosphate fertilizer, 54% P2O5 phosphoric acid and super phosphoric acid products. The plant
had been experiencing operating limitations due to lower quality phosphate rock feed and
process scaling issues around the phosphoric acid filters, which was causing excessive downtime
for filter washing.
In April 2011, Simplot contacted Hatch to help plan plant debottlenecking to increase its P2O5
production capacity by 10%.
Hatch’s phosphate engineering team has a long history with the Rock Springs facility, including
the original design and construction in the late 1980s, and a major debottlenecking project in
1999. So, along with our usual safety practices and engineering expertise, we also had excellent
knowledge of Simplot’s uniquely designed plant, which enabled us to hit the ground running.
Hatch process engineers worked closely with Simplot’s plant operators and management to
define the requirements for the plant debottlenecking.
Before this latest expansion project, the major phosphoric acid plant equipment included:
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One isothermal phosphoric acid reactor
Two #11 UCEGO rotary vacuum table filters
Three forced-circulation phosphoric acid evaporators (two first stage, one second stage)
28%, 40% and 54% phosphoric acid clarification and storage systems.
In order to increase production capacity and improve the plant’s on-stream time, Hatch
completed FEL2level studies and +/-30% cost estimates during Q3 and Q4 2011 for the following
projects:
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Elimination of the existing phosphoric acid plant cooling tower (PACT) and conversion to
utilize the existing gypsum stacking systems and cooling ponds for process water cooling
Installation of a new reactor vacuum system on the new isothermal reactor that Simplot was
constructing
Installation of a new #11 UCEGO filter, which was fabricated under close monitoring by the
Hatch Mechanical Engineering Group
Installation of a new 1st stage forced circulation phosphoric acid evaporator with FSA
Recovery
Installation of a new 80 ft diameter 44% P2O5 phosphoric acid clarifier
Installation of a new filter feed tank for the existing phosphoric acid reactor
Installation of a new rock slurry storage tank
Reconfiguration and expansion of the plant electrical infrastructure
Later in Q4, we delivered FEL3 studies and +/-10% cost estimates and got Simplot’s approval to
proceed for the following Q2. Between Q3s 2012 and 2013, we executed FEL4 detailed
engineering, while on-site construction activities were initiated in Q3 2012 for the PACT
elimination project and expansion of the plant electrical infrastructure. These were completed,
commissioned and turned over to Simplot on schedule in May 2013.
Hatch's 3D model of the Simplot Phosphates LLC Rock Springs fertilizer manufacturing facility
We re-configured the existing cooling water systems to use process cooling water in condensing
process vapor in the reactor and evaporator condenser systems. The process cooling water
system was designed to re-use hot water produced in the phosphoric acid process on the
phosphoric acid filters to reduce scaling and increase equipment on-stream time. A key factor in
this success was our process engineers’ accurate prediction of the required gypsum stack
cooling pond surface area.
The rock slurry storage tank project was completed and turned over to Simplot in September
2013 and the new reactor vacuum system is on schedule for turn-over in November. The new
UCEGO #11 filter, evaporator and 44% acid clarifier are scheduled for mechanical completion
in Q2 2014.
In September 2013 the site construction team reached 250,000 hours worked without a
recordable incident. This is a significant accomplishment, since all the new piping, electrical and
instrumentation systems are being integrated with existing systems, with all work executed in the
confined space of an operating phosphoric acid chemical facility.
We are now executing several smaller projects at the Rock Springs facility, as well as FEL1
process studies at another Simplot facility in Pocatello, Idaho.
For more information, please contact Doug Belle, DBelle@hatch.ca