Bestgrand Chemical Group has recently announced that their wet gas sulfuric acid (WSA) plant was successfully launched and is ready for use. The Chinese company has commissioned the plant to treat over-the-fence acid gas coming from the nearby China National Offshore Oil Corp and Royal Dutch Shell PLC. This is the biggest WSA plant in the world to date as it has a 300,000 tons capacity and able to treat 131,000 tons per year (tpy) of acid gas.
The plant uses the Haldor Topsoe AS which is a proprietary WSA catalytic process tech and equipment originating from Denmark. Haldor Topsoe is the company that provided the licensing tech as well as tech services, engineering design, hardware. It is also providing the performance catalysts for the project. This will be the company’s 54th plant in the country to be online since 2000 and it has 14 more plants still under construction. The companies didn’t disclose the cost of the new plant.
Impact to the Environment
Bestgrand Chemical Group is putting a lot of focus in the environmental benefits that it can provide by making use of the WSA plant. They plan to use the plant to get gas sulfur and convert it to a commercial grade sulfuric acid (H2SO4). They are predicting that the WSA plant will help reduce the carbon dioxide emission of the site by 220,000 tons per unit (tpy) as well as reducing sulfur dioxide levels to less than 50% to meet the regulations set by China when it comes to the H2SO4 industry.
The WSA plant used by Haldor Topsoe removes the sulfur from off-gas streams produced by the refining industry, steel production, and chemical production from coal. The plant transforms these sulfur gases into a concentrated form of H2SO4 which can then be sold as commercial grade H2SO4 or to be reused in the plant. This bold technology was developed and made available for commercial use back in the 1980s and was originally conceived to make the process of removing sulfur compounds more cost-effective. However, as legislation regarding environmental protection increases, the use of this proprietary technology has advanced to other applications as well.
Sulfure dioxide is a gas which is harmful to humans. It hinders proper breathing, and can be fatal for those with asthma, emphysema or other lung problems. Sulfur dioxide reacts with other chemicals and gases to form sulfate particulates associated with PM2.5 or particulate matters with a diameter less than 2.5 micrometers.
Sulfur dioxide can also form with other naturally occurring chemicals as well as pollutants to form acids, which in turn contribute to acid rain. Acid rain is the term used for rain with a high acidic level or high acidity which can damage plant life, specially food crops, the soil and can make bodies of water acidic and detrimental to fish life.
Oil and gas mines and refineries, as well as coal mines produce large amounts of sulfur dioxide. Other sources of this pollutant are gas, coal and diesel powered vehicles including cars, trucks and buses, and trains.
Sulfur recovery units are used to recover sulfur during production at a refinery. One of the methods used to recover sulfur dioxide is the Claus reaction. This is a catalytic process that converts hydrogen sulfide in gas form from natural gas and other petroleum extraction processes, into elemental sulfur. Hydrogen sulfide is also a by-product of refining crude oil.
WSA is another method of cleaning up sulfur as a byproduct of oil and gas production and in refineries. The advantage of this method is that it can produce heat during the conversion process, as well as produce industrial H2SO4 for industry.