7 Oct 2005
Successful DEA conversion with GAS/SPEC™ SS specialty amine, for increased H2S removal and lower operating costs
INEOS Oxide, producer of GAS/SPEC SS specialty amines, and Brenntag Oil & Gas, sole distributor and services supplier for this product in Europe, booked successful results at the Slovnaft A.S. Refinery in Bratislava. Since the conversion of their H2S removal system from DEA to an MDEA based GAS/SPEC SS solvent, Slovnaft’s H2S processing capacity has been increased by 25% and operating costs have been reduced significantly by 30% - 50%. Based on these positive results, Slovnaft converted a second amine unit at the refinery from MEA to GAS/SPEC SS.
GAS/SPEC specialty amines are proprietary formulations based on methyldiethanolamine (MDEA). They are formulated to meet specific gas-treating needs and to provide a level of performance that other amines cannot match. The key advantage of the GAS/SPEC product range is the ability to use the amine at a higher operating concentration of 40% to 50%, compared to the accepted DEA limit of around 25 %. The higher concentration allows more H2S to be processed per m3/h solvent circulation rate.
Energy Savings
The Amine Absorbent Recovery (AAR) unit was built as a part of the program ‘Environmental Fuel Project Apollo’ in 1999. In 2002, Slovnaft Refinery decided that the exchange MEA and DEA to MDEA was required for increased H2S processing capacity. A technology review concluded that a change from DEA to an MDEA based GAS/SPEC SS solvent could achieve the required capacity increase (with a new diesel hydro treating unit) and likely provide significant savings in energy costs.
Following a detailed modeling and evaluation by Slovnaft and confirmation with the GAS/SPEC technology supplier INEOS Oxide and Brenntag, the following expected benefits were calculated and used in a cost / benefit analysis for the financial investment required:
Savings (per ton of H2S processed)
| Expected | Actual1
|
|
| LP Steam2 | 48% | 55%
|
| HP Steam3 | - | 26%
|
| Cooling water | 50% | - 4
|
| Electricity | 30% | 41%
|
1) Compared to consumption Y 2001 and 2004
2) LP steam with pressure 0.4 MPa and 1.0 MPa
3) HP steam with pressure 3.5 MPa
4) Saving cooling water after exchange MEA to MDEA
The change of solvent
The exchange of amines was conducted in two stages:
1. Change-out of the existing DEA to GAS/SPEC® SS in May 2003
2. Change-out of the existing MEA to GAS/SPEC® SS in April 2005
The change of solvent occurred with ease and a test run was conducted mid 2003 to ascertain performance with the new solvent.
Product gas H2S specifications were met with much lower amine circulation rates (see table 1), which resulted in a significantly lower total amine circulation rate (38% reduction) in the system and as a consequence a substantial reduction of steam demand in the regenerator.
The total quantity of processed H2S increased from 2001 to 2004 by 25%. At the same time the total required solvent circulation rate was still more than 20% lower than the original DEA requirement (table 1). A full comparison of the utilities saved is given in table 2.
Some problems with gasket compatibility and solids fouling were encountered after the change of solvent, but these problems were quickly solved. In addition, two amine loss incidents have occurred, however the total cost savings are substantial with a short Capex pay-back.
Conclusion
The increased H2S processing capacity of 25% in combination with the substantial utility savings, made the change of solvent from DEA to GAS/SPEC SS at the Slovnaft Refinery highly profitable. Even allowing for normal and upset amine losses, the utility savings are such that the investments of the solvent have been paid for within a year.
Appendices
Table 1 - Comparison of absorber amine circulation rates
before and after the change
| Unit | DEA (T/H) Previous |
GAS/SPEC SS (T/H) Test Run(July 2003) |
GAS/SPEC SS (T/H)
Present day (mid 2005)
|
| VGH | 61 | 45 | 44.0– 48.0
|
| RHC | 131.1 | 73 | 60.0 – 79.0
|
| FCC | 7.7 | 5.5 | 5.0 – 6.0
|
| HDS 7* | - | - | 27.0 – 33.0
|
| TOTAL | 199.8 | 123.5 | 135.0 – 160.0
|
See related pdf file; Absorber amine circulation rates before and after the change
Table 2 - Comparison of utility use before and after change
| 2001 with DEA | 2004 with GAS/SPEC SS | 2004 / 2001
|
|
| Production:
|
|||
| H2S (kT) | 29.3 | 36.6 | 25 % increase
|
| Consumption: | Per ton H2S processed
|
||
| Steam 0.4 MPa (kT) | 151 5.2 T/T H2S | 103.6 2.3 T/T H2S | 55 % decrease
|
| Steam 3.5 MPa (kT) | 101 3.5 T/T H2S | 92.7 2.5 T/T H2S | 28 % decrease
|
| Electricity (MWH) | 837 0.029
MWH /T H2S |
611 0.017
MWH /T H2S |
41 % decrease
|
See related pdf file; Comparison before and after the change
Table 3 – Losses of amine during change
| 2001 | 2002 | 2003 | 2004 | 2005
|
|
| DEA (T) | 45 | 28 | - | - | -
|
| GAS/SPEC SS filling charge (T) | - | - | 120 | 40 | -
|
| GAS/SPEC SS upset losses (T) | - | - | - | 40 | -
|
| GAS/SPEC SS routine losses (T) | - | - | 17.5 | 19.2 | -
|
| GAS/SPEC SS total losses (T) | - | - | 17.5 | 59.2 | 20 (till date)
|
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Netherlands
Notes for editors
About INEOS Oxide, Brenntag and Slovnaft
INEOS Oxide is a proven leader in ethylene-based specialty and intermediate chemicals. They have a long and reliable track record in amine technology. Their GAS/SPEC range of products is a demonstration of their competences. These methyldiethanolamine (MDEA) based products offer the most affordable and effective method for removing hydrogen sulfide (H2S), carbon dioxide (CO2) and other contaminants from gas streams. With the help of the superb IT-based modeling tools, INEOS Oxide is able to provide a very reliable prediction of achievable savings with these products.
Brenntag is the foremost chemicals distributor in Europe and recorded sales of Euro 4.6 billion in 2004 through the efforts of 8,900 employees at 300 locations worldwide. The Brenntag Oil & Gas Team manages a full line of products and services to the oil and gas producing and processing industries. As the official distributor of GAS/SPEC® specialty amines, Brenntag Oil & Gas delivers technical support as well as chemicals & logistics services for this product.
Slovnaft A.S., which is a member of the MOL GROUP – the key oil company in Central Europe –, is one of the top 5 refineries in Europe. It processes annually 5.5. Million tons of crude oil, imported from Russian Federation. Thanks to modern technologies, Slovnaft is able to process crude oil in a highly effective way producing first-quality products with a high added value. The company supplies the market with a complete assortment of refinery and petrochemical products and plastics; about 3/4 of the production is exported to the Czech Republic, Germany, Austria, Hungary, Poland and Italy.
At the 42nd International Petroleum Conference (IPC) in Bratislava, to take place 11-12 October 2005, Slovnaft Refinery will present a paper regarding the successful DEA conversion of their amine unit. The presentation will be supported by INEOS Oxide and Brenntag Oil & Gas Europe.
GAS/SPEC is a trademark of INEOS Oxide.
Related images
Related documents
Absorber amine circulation rates before and after the change
Editorial enquiries
Claudia Boets
Brenntag Nederland B.V.
info-oilgas-europe@brenntagww.com
Folke Markestein
Marketing Solutions NV