| Filtration Technology is widely used in petrochemical plants, refineries, power plants, and many other industrial plants. As the need for energy has increased rapidly and government policies for the industries have been tightened, refineries and gas-purification plants now have more need for state of the art filtration technology than ever.
Dahlman is one of the most famous companies specializing in filtration technology, with abundant experiences in designing, manufacturing and project management. As a global supplier of filtration technology and equipment, Dahlman has maintained good relationships with famous international companies such as Shell, BP, Exxon, Mobil, etc. With their products, Dahlman have made a great contribution to chemical and petrochemical industries, refineries and the like, all over the world.
Technology and Equipment Introduction
| Refineries & gas plants |
Feedstock Filtration |
Backwash Filters, Backflush Filters, Filter Banks, Duplex Filters, Feed Filters, HDS Feed Filters, Hydrotreater/ Hydrocracker Feed Filters, Furnace Feed Filters |
| FCC Slurry Oil Filtration |
FCC Slurry oil Filter Package, Backflush Filters |
| FCC Regenerator Off-gas Filtration |
Third & Fourth Stage Separators, Bag Filters, Sintered Metal Filters, Hot Gas Filters, Dust Collectors |
| Amine Treatment |
Amine Filters, Pre Filters, Amine Particle Filters, Activated Carbon Filters, (An)Ion Exchangers, Post Filters |
| Hydrocarbons/Water Separation |
Vertical Coalescers, Horizontal Coalescers |
| Syngas Filtration |
Hot Gas Filters, High Temperature Dust Filters, Sintered Metal Filters, Bag Filters, Dust Collectors, Flash Chamber Filters, Gas Expansion Filters, Cyclo Filters, Catalyst Receiver Filters, Venting/ Aspiration Filters, Overhead Filters |
| Petro (chemical) industry |
Special Dust Filtration Systems |
Hot Gas Filters, High Temperature Dust Filters, Sintered Metal Filters, Bag Filters, Dust Collectors, Flash Chamber Filters, Gas Expansion Filters, Cyclo Filters, Catalyst Receiver Filters, Venting/ Aspiration Filters, Overhead Filters |
| Scrubbers for Dust Removal |
Wet Scrubbers, Dust Scrubbers |
| Power generation |
Gas Treatment for Biomass Gasification |
Syngas Filters, Hot Gas Dust Filters, High Temperature Filters, Sintered Metal Filters |
| Gas Turbine Exhaust Systems |
Exhaust Silencers, Exhaust Plenums, Exhaust Ducting |
| Offshore |
Water Injection Filtration Packages |
Dual Media Filters, Multi Media Filters, De-aeration Packages, Water Injection Filters |
| Specials |
Special Air Intake Systems |
Air Filters, Air Intake Systems |
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Dahlman Terraced® Filters
Dahlman has designed these specific filters to remove unwanted solids / particles out of a process flow. The filter equipment has high dirt holding capacity (DHC) and long interval between filter element exchanges. The terraced type filter element is a disposable element with a large surface of 5.4 m2 per element, combined with a thickness of approximately 3 mm needle felt. It is an ergonomical filter with a high on-line efficiency and has a short filter element change out time.
This specific Dahlman T®-Filter has the following operational benefits:
- Low filter element consumption, by longer lifetime of filter elements;
- Less operator involvement;
- Less losses of product.
Advantages Dahlman Terraced® Filters:
- Filters are available with 1, 3, 5, 7, 9 and 13 elements installed, depending on the flow rate and requested pressure drop.
- Large filter area per element, surface and depth filtration combined in one element.
- Elements available in various materials and efficiencies, depending on the requested chemical resistance.
- Element can be drained using N2 / air before replacement; product loss reduced to a minimum.
- Quick changing construction of the element; changing time reduced to a minimum.
- Very large dirt holding capacities.
- Dirt load at the inside of the element. No dirt at the clean side of the element during element changing.
- Minimum contact between the product and the operator.
- Elements are incinerable.
Technical specifications of the Terraced® Filter Elements
| Type: |
Terraced (T®) filter |
| Filter medium: |
Polyamide / Polyproylene / Ryton |
| Outside diameter: |
307 mm |
| Inside diameter: |
120 mm |
| Height: |
700 mm |
| Micron rating: |
1 / 5 / 10 / 15 / 25 / 50 / 100 µm |
| Filter surface each element: |
5.4 m2 |
| Calculated max. allow. diff. pressure: |
2.5 bar |
| Bursting pressure: |
3.5 bar |
Comparison Cartridge Filters vs. Terraced® Filters
- The T filters could handle a higher flow per square meter filter area than the existing cartridge filters.
- The T filters showed in all tests to have a much longer life time than the Cartridge filters.
- Handling of the T-filters proved to be much easier and less time consuming than the cartridge filters.
- Logistic benefits can be achieved by replacing cartridge filters with T-filters while 440 pieces of Cartridges are required against 13 pieces of T filter elements to handle the same flow.
Dahlman Automatically Regenerated Pre-coat Filter
 
Dahlman Automatically Regenerated EDF System
Dahlman Stainless Steel Etched Disc Filters. Snowflake shaped form filter candle. Chemical photographically etched 50 micron thick SS 316 sheets with 7 micron absolute micron rating. For direct filtration of liquids with sticky solids. Main applications FeS removal from amine systems.
- Pure surface filtration
- No particle migration
- Backflush up to 30 bar
- 7 micron absolute filtration
- No external cleaning.
Application
Automatic Backflush Filtration packages
Typical applications:
- Feed HDS unit
- Feed Hydrotreater
- Feed Hydrocracker
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- Vacuum tower bottoms (short ends/ vac resid)
- Atmospheric tower bottoms (long ends)
- Product (delayed/flexi) coker
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Dahlman FCC slurry oil filtration systems
Potential usage for filtered MCB/ SO:
| No. 6 or Bunker C. fuel oil: |
50-150 ppm |
| Coker feedstock: |
50-150 ppm |
| Anodic/ needle grade coke/ pitch feedstock: |
25-100 ppm |
| Carbon black feedstock: |
50-500 ppm |
| Boiler or Furnace oil: |
50-150 ppm |
| Industrial and electric utility fuel: |
50-100 ppm |
| Industrial and electric utility fuel: |
5-10 ppm |
| Residue hydrocracker feedstock/ diluent: |
10-50 ppm |
MCB / slurry oil characteristics
| Specific gravity: |
~ 850 kg/m3 (230 - 290 °C) |
| Viscosity: |
~ 1 cP (230 - 290 °C) |
| Operating temperature: |
260 °C (230 - 290 °C) |
| Type of element: |
Sintered powder metal (NO sintered wire mesh) |
| Fluxrate: |
Use 0, 5 m3 /m2.hr @ 1 cP for standard applications
Use 0, 7 m3 /m2.hr max @ 1 cP for large systems (vessels > 48") |
| Solids concentration: |
Typically 1000 - 8000 ppm |
| Micronrating elements: |
Typically 0.5 - 1 µm nominal |
| Typical design temp.: |
400 °C (Main Column design temperature) |
| Typical design pressure: |
12 barg (MCB circulation pump shutoff pressure) |
Dahlman Amine filtration systems
 A mine systems suffer from:
- Foaming
- Bio waste water upsets
- Corrosion
- Off spec products
- Plugging
- Flaring Incidents
- Amine losses
- Decreased throughputs
- Un-planned stops
Amine system problems and solutions:
- Heat Stable Salt Degradation products: Removal by Ion Exchange
- Heat Stable Salt Degradation products: Removal by Ion Exchange
- Hydrocarbons: Removal by Activated Carbon or Solvent Extraction
Biomass gasification
Gas cleaning in biomass gasification
- Dust removal - fly ashes
- Tar removal - heavy & light tars (phenol)
- NH3 / H2S removal
Environmental issues
- More stringent national and international regulations, for reduced solid, liquid and gaseous emissions
- Low-sulphur gasoline and ultra-low sulphur diesel products
Economic reasons
- Declining availability of low-sulphur crude resulting in increasing costs compared with high-sulphur crudes
- Increasing difficulty of coke disposal (hazardous waste)
- Increasing need for hydrogen on behalf of low-sulphur fuels
Gasification process in general
Conversion (by partial oxidation) of a carbon-containing gas, liquid or solid material into a synthesis gas, in which the major components are hydrogen (H2) and carbon monoxide (CO).
- Declining availability of low-sulphur crude resulting in increasing costs compared with high-sulphur crudes
- Increasing difficulty of coke disposal (hazardous waste)
- Increasing need for hydrogen on behalf of low-sulphur fuels
Typical (hazardous) refinery waste and feedstock for gasification, "Heavy oils/residues", like:
- Vacuum residue
- Visbreaker tar
- Asphalt
- Petcoke
IGCC (Integrated Gasification Combined Cycle technology)
- Production of electricity for power export and internal use
- Production of hydrogen for hydroprocessing facilities
- Outlet for the refinery's heavy residue
References
Worldwide
Refineries and Gas Plants: Shell, Kuwait, Mol, Fortum, Scanraff, Statoil, Slovnaft, Total, Veba, Nerefco, Esso, Elf Oil, Erg Petroli, Scanraff, ISAB Energy, etc.
Petro(Chemicals): DSM, ExxonMobil, Basell, Akzo, DuPont, Dow, Lyondell, Sabic, BP, etc.
Power Generation: Electrabel, E-on, Nuon, BHEL, Kulim, Gas Transport Services, etc.
Offshore: Bluewater, ExxonMobil, Statoil, Shell, etc.
China
FCC Slurry Oil Filtration:
1. SINOPEC/ Shenli, China (started up successfully in 2000
2. CNPC/ Dagang Refinery, China (Largest unit installed in China)
Polyol Filtration Package:
1. CSPC Naihai
For more information please contact Hofung Technology or send an email to sales@hofung-technology.com.
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