In the steel industry, a large amount of degreasing agent is required in degreasing solutions used to skim off oil and grease from iron and steel surfaces. As the degreasing and cleaning ability of the agent decreases after each subsequent use, there is a consistent need for it to be replenished in the solution. The reasons are as follow:
- Degreasing agents undergo a series of physical and chemical reactions with oil and water (including saponification, emulsification, dispersion, dissolution etc.)
- Degreasing agents dissolve into emulsified oil (oil-in-water O / W), thus it is unable to come into contact with the metal surface
- When the emulsified oil content in the degreasing solution tank reaches 20-30g/L, the solution is no longer effective and needs to be replaced
Conventionally, the waste degreasing solution is discharged into its surrounding environment after going through a simple wastewater treatment system.
By using Hyflux’s FerroCep® stainless steel tubular membrane in an alkaline-based degreasing solution processing system, the still-active alkaline degreasing agent can be separated from oil, emulsified oil, grease and sludge. Subsequently, the still-active alkaline degreasing agent can then be recycled back to the degreasing solution tank for reuse. Besides reducing the daily amount of degreasing agent used, the life cycle of the degreasing solution is substantially extended, thereby greatly reducing procurement costs.
FerroCep® is largely used in the iron and steel, electroplating, machining industry for its ability to separate oil-water in degreasing and bleaching processes. It can also be applied to the cold-rolled steel industry in emulsion wastewater treatment.
FerroCep® stainless steel tubular membrane is used to retain emulsified oil, particles and other impurities; filtering online/waste degreasing solutions and recycling permeate for reuse purposes.
Waste degreasing solution discharged from degreasing tanks in steel factories undergo pretreatment through a pre-filter to remove iron fillings and other impurities before entering the re-circulation tank. During circulation, driven by pumps, waste degreasing solution pass through FerroCep® stainless steel tubular membranes that retain emulsified oily-wastewater, while allowing permeate to return back to the degreasing solution tank for reuse. The filtration process is stopped when emulsified oil concentrations in the re-circulation tank reach a certain value. The concentrated emulsified oil wastewater will then be treated with a simple wastewater treatment step.
Reference of clients in China that use FerroCep® tubular membrane for industrial purposes:
- United States Cold-Rolled Sheet Plant
- Crown Chau Co., Ltd.
- Magnesium Alloy Shanghai Co., Ltd.
FerroCep® is one of the world's strongest stainless steel tubular membrane with high shock-load resistance. Based on proven technology and a patented coating technology; a rugged stainless steel tube is sintered with a titanium dioxide layer that bonds permanently to the tube’s porous surface.
FerroCep® has the durability to fully withstand extreme process conditions that are of high-temperature, pressure, solvent concentration and pH value. At the same time, FerroCep® has an extraordinary operating lifespan, far beyond any ordinary filtrating membrane in the market.
Using stainless steel membrane technology for the recovery of degreasing solution in the iron and steel industry is a piece of technological innovation. FerroCep® stainless steel membranes thus have the following technological and economical benefits:
- Highly stable and unique support structure - 316L stainless steel tubes
- Highly stable membrane material - patented TiO2 inert material
- Wide-channel inorganic membrane - membrane tubular diameter (19 mm)
- Precise filtration capabilities - pore sizes (20nm, 100nm)
- Reliable seamless fabrication - welded seal; without any O-ring
- High oil retention rate
- High stability of discharged water quality
- High temperature tolerance
- Resistant to extreme pH
- Easy to clean and restore permeability
- High flux stability
- No leakages
- Long service life
- Wide application use
- Able to handle 0.5-10.0% of emulsified oil wastewater content
- No additional chemical required to concentrate oil content up to 20%
- Small footprint
- Automated - Simple operating and maintenance procedures
FerroCep® economical benefits:
- Reduce operating cost for degrease processing and wastewater treatment
- Cost savings in cleaning chemicals (e.g. water consumption, cleaning agents)
- Cost savings in energy consumption (heating of degreasing solution)
- Reduce volume of wastewater discharge; environmentally friendly
- Improve feed quality for upstream pretreatment
- Reduce maintenance of cleaning line
- Improve workers’ health and safety in working environment