2. Plant Design
The proposed styrene process plant was designed up to Level 4 in Douglas’s Hierarchical
Decision Procedure for Process Synthesis[2]. The proposed plant consisted of multiple heating and cooling
units, an isothermal reactor, and a separation system. Operating conditions and equipment specifications
were optimized using discounted cash flow analysis and economic analysis from Level 1 to Level 4.
The overall process design began with fresh ethylbenzene mixing with steam. This feed was
heated through a series of heat exchangers using different process fluids. The heated feed reacted in the
gas phase through a packed bed reactor to generate required flow rates of styrene. The reactor effluent
4
was cooled using a similar heat exchanger set up. A separation system purified the organic liquid effluent
to individual species (≥99 wt. %). The byproduct gases were used as process fuel and sold for fuel value.
The unreacted ethylbenzene was recycled to achieve operating conditions determined by economic
analysis.