Gazpack - Model Sulaway - Biomethane Upgrading Plant
The Sulaway® unit is the heart of the Gazpack installation and fully customer specific. Our Suluway® is built to convert large capacities of biogas to biomethane (>1500 Nm³/h). Therefore, a wide range of capacities can be achieved. Thus, we can offer solutions for large-scale upgrading and the system can handle high H2S content.
1: Grid injection
In order to comply with the climate commitment made at the COP21 in Paris, all gas supply must by renewable and decarbonised by 2050. Therefore, Gazpack is delivering a high-quality system which can provide a biomethane purity up to 99.5%. Moreover, we can clean the biogas until it complies with de Wobbe index (44-55 MJ/Nm3), which makes it possible to inject it into the gas grid.
2: C02 Recovery
Additionality, our Sulaway® system must remove CO2 to deliver high quality biomethane. The carbon gas can be liquefied and stored, which means an extra stream of revenue is feasible within our system. Due to liquification of our high-quality CO2, it is possible to use it for green houses or sell it to the food and beverage industry.
3: Acid water
The third outgoing stream of the Gas Purifier is H2S, which is transformed into acid water by our quencher. Acid water can be used for fermentation, as well as for batteries. The essence of the Gazpack system is that it is a closed loop system that produces a limited amount of waste compared to other gas cleaning systems. Waste disposal, especially when saturated with sulfur, is costly and environmentally unfriendly.
The Sulaway® unit is built according to the highest quality and safety standards in the industry. The main features of the package are explained below.
All pressure-regulated instruments are pneumatically controlled. In case of alarm or shutdown, the installation will automatically stop and all instruments will turn to their safe positions.
The unit is completely enclosed by a gas tight enclosure. In case of an emergency or gas leak the installation is stopped and a process is started to burn off excess gas in the system through an incinerator, which is part of the quencher. There is always a backup supply of nitrogen in order to have a safe shutdown.
Several high power components are used inside the Sulaway® system. Nevertheless, the complete energy balance is well thought out. For example; heat generated by the compressor is used for the regeneration of the Sulabeads®. Additionally, the water collected from the saturated gas is used in the quenching process; only a small amount of additional water might be required.
Standby safety purge system
For purging of the Sulaway® unit, inflammable Carbon Dioxide can be used. The Carbon Dioxide can be filtered out of the green gas by means of membranes which can be added as an additional part of the package.
During the development of the Sulaway® process, the basis was to make a system which would clean gas without producing any waste materials. Existing H2S removal processes all have waste products or high running costs due to continuous requirement of, for example, fresh water, filter replacements or activated carbon. The operational costs are relatively high as well, due to destruction or removal of the corrosive waste products. This is a difficult, time consuming and therefore expensive job. The production of biogas itself is already a sustainable process and an alternative energy source. The Sulaway® unit only adds to this sustainable process by providing usable output with no waste.
The trend in sustainable energy production is that (bio) gas production facilities all have the goal to upgrade the gas and create electricity with it. However, we believe this does not have a future in many countries and does not present a viable business case.
Low electricity price, low energy efficiency and lack of storage possibilities for electricity make it more interesting to produce and use green gas. The best opportunity for gas producing facilities, such as large cattle farms or wastewater facilities is to seek a nearby user of natural gas and supply the cleaned gas from the Gazpack unit to the gas turbines of that user. Simply mixing the natural gas with the cleaned (bio) gas will leave the total gas flow within the boundaries of turbines and severely decreases the usage (and costs) of the natural gas.
The best example of sustainability however can be found in the fact that reducing the natural gas usage and increase its green gas usage will give your company the opportunity to have a green image, a priceless but valuable appearance in today’s world. This statement is enforced by the benefits of the Gazpack system on both technology and environment.
1: Reduction of toxic exhaust gas particles: NOx CO and SO2
Clean biogas produced by the Sulaway® unit burns better than raw biogas, reducing the dangerous and toxic exhaust particles in the air.
2: Decrease of carbon dioxide (CO2) content
The gas purifier does not only remove Sulfur but is also capable of removing CO2 from the biogas reducing its carbon footprint.
3: Lethal Sulphur (H2S) converted into a usable product
Sulfur is an unusable product when mixed within the gas. When removed using other methods Sulfur is often bonded to a carrier. Carrier and Sulfur are often burnt by waste removal companies producing a high amount of toxic gas particles in the air. Gazpack removes the Sulfur and generates a high concentrated H2S gas stream to be used for different purposes. The carrier is regenerated to be used for the next cycle of cleaning gas.
4: Solid build
Gazpack installations are build according to the latest standard and industrial, safety and environmental requirements.
5: No more odor and gas leakages
The Sulaway® unit is completely enclosed, leak free and equipped with state of the art safety devices ensuring a safe working environment.
6: Sulabead100® is mechanically strong
Oxygen, Cyanide and other aggressive elements do not harm the Sulabead®.
7: Increased fertilizer quality ( for biogas only)
The ammonium removed from the air of the stables produced by the scrubber can be used as a fertilizer to significantly enhance the quality of manure.
- Impregnated Molecular sieve (Sulabead®) instead of active carbons, which means lower maintenance and transportation costs
- Production cost low due to the regeneration of Sulabead®
- Low carbon foot print due to absence of extremely polluting active carbon
- No water required nor wasted water to clean
- Drain water is used for production of Sulphuric acid (H2SO4)
- At high H2S concentrations the acid production will be profitable
- The complete process is liquid glycol cooled to obtain highest efficiency
- The heat from the chiller can be used for district heating and is higher than the electrical power consumed due to condensation heat of the drainwater
- Low power consumption
- Maintenance costs are low due to the long life to the adsorbent and compressor
- Due to intensive water removal upstream - no aggressive liquid acids: H2CO3 and H2SO3 - and water-cooled oil cooler, there is a long oil change interval
- The production costs are low due to absence of wastewater or coal
- For maintenance shut down CO2 is used as a safety gas instead of Nitrogen for two reasons: CO2 is ample available and keeps smoke gas free from Nitrogen impurities
Extra investment costs due to process equipment:
- Two (2) heat exchangers
- Two (2) pumps
- Steam boiler
- Reflux drum
- Basic material Amine
- Consumption of steam and water
- Sulaway decreases costs by transforming H2S in sulfuric acid
Maintenance costs daily for amine plant
- Sulaway plant checkup each half year for gas compressor.
- The cleaning process of biogas using a amine plant, is not an acceptable process on agricultural land due to the heavy sewer water pollution
Biological H2S removal is a danger for the environement
- An amine plant is a cheap investment, but extremely expensive in production and maintenance.
- H2S content from 10.000 up to 100 ppmV
Extra investment costs due to process equipment:
- Blower/booster compressor
- One (1) heat exchanger
- Sewage treatment plant to wash water
- Active coal
- Extra electric power
- Water consumption
- Loss of methane(CH4)
- Daily attention of biologicals
- Sulaway plant checkup each half year for gas compressor
- Sewage water plant produces Sulphuric acid (4 %)
- Sulaway decreases costs by transforming H2S in sulphuric acid (H2SO: 85 %)
A SULAWAY package has an easier and cheaper process than the Claus plant. Our package produces sulphuric acid (H2SO4) instead of sulphur. For the acid (about 85 % purity), a profitable market is available.
Sulphuric acid (H2SO4) has many applications:
- In the oil refinery for production of gasoline
- Batteries for the automotive industry: electric cars etc.
- Manufacturing fertiliser
- Gas drying
- Reagents for organic syntheses
Sulphur is a non-sellable product, in the contrary customer has to pay for waste processing.
The SULAWAY plant is two times more expensive, but its return on investment is less than five years due to the sales of acid ( H2SO4)