PHENOL PLANT PROCESS DIAGRAM
Phenol Complex consists of the following units
Brief process description of each unit is given below.
Propylene Recovery Unit
The plant is designed by Engineers India Limited to produce two grade of propylene Viz. Lean propylene of 75% purity suitable for the production of Cumene and Chemical grade propylene of 95% purity.
Capacity of the plant
The process scheme consists of two fractionation columns with the auxiliaries and equipment for the removal of COS (Carbonyl sulphide) as H2S from the hydrocarbon. The first fractionator acts as C3-C4 splitter producing 75% propylene as top product. The second fractionator functions as C3-C3 splitter producing 95% propylene as top product. Propylene from C3-C4 splitter is treated in Caustic/MEA and water washing system to remove the sulphur.
This unit is based on UOP’s Catalytic Condensation process. This processing technique utilises a solid phosphoric acid (SPA) catalyst to promote the alkylation of benzene with propylene to yield high purity Cumene (isopropyl benzene).
The overall process flow scheme consists of combining benzene with a propane – propylene mixture at select ratio prior to the reaction zone for insurance of maximum product quality and yield. This mixture is then heated and routed to the reaction zone, where the alkylation takes place over a solid phosphoric acid catalyst. The reaction zone effluent then passes through a series of fractionation columns for the rejection of non-reactants; recycle of the unreacted benzene and for the separation of the desired Cumene product from the heavier alkylated product.
This unit is based on UOP’s CUMOX process, which is a commercially established Cumene per oxidation process for the economic and efficient production of phenol and acetone.
The CUMOX unit has been divided into the following process section.
In this section, CHP is concentrated in two steps from approximately 25-wt % to 80-wt%.
Concentrated CHP from the evaporation section is fed into two parallel cleavage reactor circuit along with concentrated sulphuric acid catalyst. Under controlled condition of temperature and acidity, CHP is cleaved to phenol and acetone and byproducts.
Direct Neutralisation & Effluent Treatment Section
This section perform four main functions:
This section mainly consists of six columns to separate and purify phenol and acetone and to recover Cumene and AlphaMethylStyrene (AMS).
The alphamethylstyrene (AMS) is hydrogenated back to Cumene. The reaction is carried out over a fixed bed of catalyst.
Hydrogen peroxide plant
This plant is based on UHDE’s Ethyl Anthraquione process .2-Ethyl anthraquinone (2-EAQ) the effective reactive component is dissolved in mixture of solvent called working solution. It is reduced by hydrogenation using palladium catalyst in the first step and further oxidized to generate Hydrogen peroxide and spring back 2-EAQ.
The hydrogen peroxide generated is extracted from the working solution using demineralised water. The working solution is recycled back to the hydrogenator and the above - mentioned reactions are carried out repeatedly.
The weak hydrogen peroxide (35% concentration) is subjected to vacuum distillation to increase the strength to 50% or 70% as per the requirement.
A small portion of working solution prior to hydrogenation is subjected to chemical treatment to remove or control the accumulation of side reacted products.
The process flow diagram for hydrogen peroxide plant is enclosed as figure.2
H2O2 PLANT PROCESS BLOCK DIAGRAM
The phenol and Hydrogen peroxide plants are provided with these service systems.
Effluent Treatment Plant
The effluent from different plants is collected in equalization tanks. The combined effluent is then treated by physical, chemical and biological methods.
The treated effluent conforming to the norms specified by Kerala State Pollution Control Board is only let out from the factory.
EFFLUENT TREATMENT PLANT BLOCK DIAGRAM
PROCESS CONTROL SYSTEM
The plant has a DCS system (Distributed control System )
Hindustan Organic Chemicals LimitedOffice No: 401,402 and 403, 4th Floor,
Regional Offices :
Kochi : Hindustan Organic Chemicals Ltd.Post Bag No : 18, Ambalamugal P.O.
DelhiCore 6, First Floor,