Utilities and Storage facilities

Utilities are important factor for deciding profitability of the plant. The term "Utilities" is generally used for the ancillary services needed in the operation; of any production process. These services will normally supplied from a central site facility, and will include:

12.1 Electricity

12.2 Steam, & process heating

12.3 Cooling water

12.4 Water for general use

12.5 Effluent disposal facilities

12.6 Nitrogen for blanketing storage tanks

12.7 Special heat transfer fluids

12.1 Electricity

The power required for the processes, motor drives, lighting and general use may be generated on site, but more usually will be purchased from the local company.  The voltage at which the supply is taken or generated will depend on the demand. In this plant there is not much scope for starting a captive power plant.

12.2  Steam

 The steam for process heating is usually generated in water tube boilers .The high heat of reactions helps in generating more than required amount of steam. The steam produced is used wherever required.

12.3 Cooling water

Natural and forced - draft cooling towers are generally used to provide the cooling water required on a site unless water can be drawn from a convenient river or lake in sufficient quantity.

12.4 Water

 The water required for general purposes on a site will usually be taken from the local mains supply, unless cheaper source of suitable quality water is available from a river, lake or well.

12.5 Effluent disposal

 Facilities will be required at all sites for the disposal of waste minerals without creating a public nuisance.  The disposal of aqueous waste and toxic waste to public sewers and surface waters is controlled by legislation.  Strict controls are placed on the nature of effluent that can be discharged. In this plant lot of heavy organic materials are obtained. These materials can be combusted and the energy can be harnessed in the form of heat.

12.7 Special Heat Transfer Fluid

Special heat transfer fluids are used when steam cannot be used (usually more than 180⁰C ). Dowtherm, marlotherm etc. are examples.

12.8 Storage

12.81 Ethylene oxide Storage facility

Ethylene oxide has high vapor pressure at room temperature and at 1 atm.  Therefore it is stored in its liquid form under 15-bar pressure. Storage under high pressure N₂ atmosphere is done in order to avoid the potential hazards associated with vapor storage of ethylene oxide. A cylindrical type of pressure vessel is chosen for storage. Stainless steel can be used as the material of construction, but before use, must be cleaned and treated to remove rust and grease.

Contamination of stored oxide due to back flows and cross connections by impurities that could cause polymerisation, must be avoided by proper design and operation of transfer systems. Mirror finishing of the inner surface of storage tank avoids polymerisation.

12.82 Ethylene Carbonate Storage facility

Ethylene carbonate is stable under normal conditions. It has a freezing point of 36.4 C. So it exists as a solid at room temperature. But ethylene carbonate finds its application in market as a solvent. Hence it is necessary to store it in its liquid form at 60-70 ^oC. The storage tanks are provided with steam coils to maintain the temperature. Stainless steel is used as a material of construction. In order to maintain the colour of product, the inner walls are made smooth and ensured that they are free of corrosion traces.