Optimized Gas Treating
6 November, 9:30 am
It is known fact that adding phosphoric acid to N-methyldiethanolamine (MDEA) solutions in tail gas treating units (TGTUs) enables significantly deeper stripping of hydrogen sulfide in the regenerator and permits tail gas to be treated to as low as 10 ppmv H2S. Heat stable salts such as formate, acetate, thiocyanate, and thiosulfate are the organic equivalents to phosphoric acid and function in exactly the same way. Just like phosphoric acid, under the right absorption conditions they can greatly enhance hydrogen sulfide removal. This contribution explains the mechanism through which stripping promoters act, it shows that removing HSSs to very low levels can be detrimental to the operation of TGTUs, and it provides guidelines as to when, and how much, HSSs should be left in the treating solvent.
Parker Hannifin is one of the world leaders in filtration equipment and consumables in various application fields among which sulfur burning acid plants.
Parker Twin Filter understand the challenges, operators face in sulfur melting and filtration processes. Filtration of liquid sulfur is required, to remove (incombustible) solids to minimise the number of turnarounds required for cleaning the convertor tower and screening/replacing the expensive catalyst.
Liquid sulfur (primary) filters
The Parker liquid sulfur filter is a state of the art filter (pressure leaf). It comprises of a horizontal filter tank furnished with, vertically positioned, filter plates. The tank is fully steam jacketed on the sides, dish heads, cover closure and all nozzle connections in order to avoid undesired solidification of liquid sulfur. The heated bayonet closure, hydraulically operated, prevents solidification of sulfur on the sealing surfaces of this flange. Sulfur leakages requiring the filter process to be discontinued, now belong to the past.
No disconnection of piping
All process connections required, are situated at the stationary head of the filter, hence no jacketed piping (sulfur piping) need to be disconnected when the filter needs to be opened for cleaning. Other advantages are during cleaning procedure:
- Filter plates stationary at all times (no premature cake release).
- No disconnection of piping (safety for operators).
- No moving parts above the filter plates.
- In case of a power failure the tank can be manually retracted.
Polishing filters for liquid sulfur filtration
Polishing filters are vertical pressure vessels equipped with filter cartridges positioned in series with the primary filters.
These polishing filters will further reduce ash levels in the sulfur sent to the burner/convertor tower. Also, the polishing filter will act as a police filter in case the primary filter malfunctions.
A 1 million tpd sulfur burning plant produced 15 - 20 kg/d solids (dirt), most of this material will settle down in the convertor tower causing a raise in pressure drops and contamination of the catalyst. After the installation of a polishing filter the same acid plant now accumulates only 3 kg/d of dirt (solids), a reduction of 80% versus the initial situation.
PROSERNAT, subsidiary of Heurtey Petrochem, is a specialised process technology and equipments supplier to the oil and gas industry worldwide.
PROSERNAT offers a full range of onshore and offshore skids mounted units for the complete gas chain, including the following applications: phase separation, natural gas dehydration and sweetening, NGL extraction, CO2 capture from flue gases, sulfur recovery and MEG regeneration and reclaiming.
As of today, the company has many world class references with all major international and national oil and gas companies:
- References as early as 1957.
- Total sulfur production of more than 30 000 tpd using PROSERNAT technology.
- References in operation up to 2200 tpd per single train.
PROSERNAT has developed a specific and unique know how in the design and supply of modular sulfur recovery units to be installed in harsh climate conditions and suitable with train transportation.
Sandvik Process Systems
Sandvik engineers total sulfur solidification and handling systems, delivering turnkey projects covering everything from acceptance of molten sulfur direct from the sulfur recovery unit (SRU), to bulk storage and truck, rail and ship loading facilities.
The company expanded its product portfolio in early 2014 by purchasing the proprietary technology and know how of the Calgary based Brimrock Group Inc., a move that has significantly extended Sandvik’s offering to refineries. In addition to its widely used, small/mid capacity Rotoform pastillation system, Sandvik can now deliver high capacity solidification in the form of its Brimrock RS1500™ process, with rotating drum technology delivering fast and reliable sulfur granulation to SUDIC specifications.
Sandvik can also offer a proprietary liquid sulfur degassing process for removing H2S from molten sulfur, with high throughput rates through a wide range of sulfur H2S levels. Other processing systems available from Sandvik include include sulfur remelters capable of handling pure or contaminated sulfur, and block pouring systems for the cost effective, long term storage of high volumes of sulfur.
The company also offers a full range of consulting and engineering services and can provide in depth support with plant layout, specifications, design and equipment recommendations.
Shell Cansolv, a fully owned subsidiary of Shell Global Solutions B.V., is an innovative, technology centred company that offers its clients high efficiency gas capture solutions for the removal of sulfur dioxide (SO2) and carbon dioxide (CO2) from gas streams in various industrial applications. Shell’s commitment is to provide custom designed economic solutions to our clients’ environmental challenges. In upstream, the technology can be used in sulfur recovery units (SRU) for gas processing plants which process sour and contaminated natural gas streams. In downstream, the technology can be used to treat FCC regenerator gas, coker off gas, combustion flue gas from high sulfur fuels and in SRUs.
- >Cansolv SO2 scrubbing system: The Cansolv SO2scrubbing system controls emissions and captures additional byproduct value from the SO2 emitted in various flue gas streams, such as those generated by fluidised catalytic cracking units, process heaters and boilers, sulfur plants and spent acid regeneration units.
- Cansolv CO2 capture system: Operating on the same principle as the Cansolv SO2 scrubbing system, the Cansolv CO2 capture system is a world leading amine based CO2 capture technology.
- TGT+: The Cansolv TGT+ (Tail Gas Treating Plus) process can help to achieve the most stringent emission standards at a competitive cost while minimising complexity. The process also provides an outlet for disulfide oils and other off gases.
- Cansolv SO2/CO2 integrated system: As a leading provider of both SO2 and carbon dioxide CO2scrubbing technologies, Shell Cansolv is uniquely positioned to offer an integrated system that uses the same technology to sequentially scrub SO2 and CO2.
Shell Cansolv’s technologies use regenerable amines to remove SO2 and CO2. These regenerable solvents can make the processes more cost effective and also minimise environmental waste.
Sulphur Experts has been troubleshooting and optimising sulfur recovery plants for decades, providing independent process and operations training and engineering solutions to improve recovery efficiency and solve operational and design problems.
The company's unique approach, combining specialised analytical capabilities with expert engineering evaluation, results in the highest efficiencies and onstream times for the critical sulfur recovery unit (SRU) and tail gas treating unit (TGU) operations.
With offices in Barbados, Canada, USA and the Netherlands, Sulphur Experts, together with its amine experts, energy experts and filtration experts divisions, have the ability to test, troubleshoot and optimise amine treating, sulfur recovery, tail gas clean up, incineration, sour water stripping systems, filtration systems and separators anywhere in the world.
Sulphur Experts also specialises in on site gas and liquid analysis, with focus on sulfur species. Tests have been conducted for well head appraisal and feed gas to and from process units for H2S, COS, CS2, mercaptans, thiols and all other sulfur species of interest.
Adapted for the web by Emma McAleavey.
Read the article online at: https://www.oilfieldtechnology.com/special-reports/09102014/sulphur-show-preview-1374/