Cyclohexane Production Unit

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Cyclohexane Production Unit

• Presented by Brian Clifton

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Executive Summary

• The cyclohexane production plant is not
  economically feasible unless the price of
  cyclohexane is more than double the price of
  benzene.
• Yellow does not recommend IRI to proceed with the
  plans to build and operate this facility.

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Outline

• Process Overview
• Economic and Risk Analysis
• Pipe Network
• Pump System
• Heat Exchanger
• Distillation Column

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Process Overview

• Benzene is hydrogenated in a Gibbs reactor at
  high temperature and pressure to form cyclohexane

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Process Overview
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Economic Analysis
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Economic Analysis

• Production Cost 7.14/gal
• Revenue 3.60/gal
• TCI 2.5 million
• NPW negative 1 billion
• Accuracy 10
• Required ROI 8

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Strauss Plots/Propagation of Error

• Strauss plots for FCI, product cost, and product
  cost
• Propagation of error method

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Monte Carlo Simulation
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Piping System

• Piping materials made of stainless steel
• Insulation thickness of 1 inch
• Schedule 40 pipes increased to schedule 80 to
  operate under bursting strength
• FCI of 900,000 for piping system

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Piping Specifications
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Pumping Section

• Cyclohexane is pumped from the process to a
  storage tank at 555 psia which is 35 feet above
  the flash tank

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Pumping Section
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Pump Section

• Piping
• All pipe are stainless steel schedule 40
• ability to resist corrosion

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Pump Section

• Pump
• Positive displacement pump
• 9 hp required
• 415 ft head available
• All components are stainless steel

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Pumping Section

• Cost for installation of the pumping section,
  including the pump, pipes, and valves, was
  determined to be 105,000
• Total fixed capital investment for the
  cyclohexane plant up to 2.4 million.

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Heat Exchanger Network

• There are three heat exchangers in the
  cylcohexane plant
• The heating utility required by the plant is
  minimized by using the hot product stream to
  pre-heat the incoming reactant stream.

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Heat Exchanger Network

• Heat exchanger 1 was designed rigorously
• A temperature heat diagram was created

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Heat Exchanger Design
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Heat Exchanger Design

• The single pass, countercurrent design was
  selected
• No baffles were
• used, in order to
• maintain the
• shell-side pressure
• drop under 5 psi

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Heat Exchanger Design
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Heat Exchanger Design

• Triangular pitch
• Stainless steel heat exchangers
• Hot streams were maintained tube side in all heat
  exchangers
• Heat exchanger 2 uses steam to heat the reactant
  stream
• Heat exchanger 3 uses cooling water to cool the
  product stream

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Distillation Column

• 30 theoretical trays
• Optimal feed location 16th tray
• Column height
• 32 feet
• Column diameter
• 42 inches

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Distillation Column

• Valve trays
• 94 valves / tray
• Tray spacing
• 24 inches
• Condenser heat duty
• -1.9 MM Btu/hr
• Reboiler heat duty
• 3.01 MM Btu/hr

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Summary

• After the detailed designs were conducted, the
  cyclohexane plant was shown to not meet IRIs
  criteria for profitablity.
• Yellow does not recommend IRI building and
  operating this facility.

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Questions
?