Reference no: EM133126044
EG463 Process Design - Queensland University of Technology
Assessment: Environmental Impact Assessment
Seawater desalination provides safe drinking water for regions with freshwater shortages in many different locations globally and can help to protect and relieve the ground water resources from excessive usage. However, desalination causes negative effects on a wide range of environmental issues: considering both the intakes and outfalls of a SWRO desalination plant, write a report covering the environmental issues and impacts.
1. For the intakes consider
• Impingement and entrainment
• Relative location of plant and intake
2. For the outfalls consider:
• Temperature
• Salinity
• Dissolved oxygen
• Discharge of chemicals for pre-treatment and membrane cleaning
• Discharge of metals from corrosion (Cu, Fe, Ni, Mo, Cr).
Use references from previous industry reports, standards, government regulations, and engineering & scientific literature to prepare your report. It should be noted that the word limit is the maximum of 2,000 words excluding references.
1b: Design Pumping and Piping for the RO Desalination Plant
In a Reverse Osmosis (RO) desalination plant, the feed water (or saline water) is transferred by a high-pressure pump (HPP) up to 60-80 bar and then passed through saltwater reverse osmosis (SWRO) membranes in an enclosed vessel. The energy consumption of the pump is increasing with the increase of membrane pressure. By using an energy recovery device (ERD), the energy consumption can be significantly reduced. The membranes selectively block most dissolved solids and salts and let pure water pass. The accumulated saline water (or brine) is discharged back to the sea via an outfall tank. Depending on site considerations, the brine discharge may be regulated in accordance with the tide and ocean currents. The amount of fresh water (or permeate) produced depends on the applied pressure and salt content of the feed water. Depending on the application and the feed water characteristics several membrane materials and configurations can be applied. The first successful membrane material on the market was cellulose acetate. Today a mix of cellulose di- and tri-acetate is usually used. However, synthetic polymer materials are increasingly replacing the natural cellulose membranes. This is mainly due to the better salt rejection and the higher durability of synthetic materials. For example, polyamides resist high pH ranges and cope better with biological attack and other feed water pollution.
Design a pumping and piping system for this SWRO desalination plant to transfer saline water from the ocean to the plant. The specific parameters are presented in Figure 1. In addition, there is further information below:
a. The maximum intake and outlet velocity should be maintained equal to or below 0.15 m/s.
b. The recommended velocity range for suction and delivery lines are 1-2 and 1.5-3 m/s, respectively.
c. The pipe lengths are self-selected depending on the scale of the plant or the location of the plant that you want to design and install.
d. For required parameters which are not specified, undertake research from published scientific and engineering literature as well as manufacturer information. The assumptions should be referenced and based on "good design practice".
Please complete the following tasks (Note: representative manual calculations are to be done for all questions. Comment on any differences found)
1. Draw a schematic diagram of your RO plant with the following items
• The selected pipeline materials, length, diameters, and their associated head losses (based on good engineering practice and standard).
• All pump selection.
• Other components in your diagram.
2. Estimate the energy of the HPP on an annual basis in kWh. If electricity costs 15c/kWh what is the total annual cost of electricity? Comment on the magnitude of this cost in comparison to benchmarks of other RO plants in the literature. Use the units of kWh/(m3 of permeate) for the benchmark.
Attachment:- Process Design.rar