Sulfuric Acid Regeneration Plants EPC Solution SAR Sulphuric Acid Recovery Plant

Customized EPC Solutions for Acid Regeneration Plants

Utilizes spent sulfuric acid or waste acid from industrial processes, such as chemical manufacturing, petroleum refining, and metal processing.

The sulfuric acid regeneration (SAR) process involves a series of carefully controlled steps to convert spent sulfuric acid back into fresh, high-quality acid. The process begins with the concentration of the incoming feed acid to remove any excess water, reducing the overall volume of the spent stream. This concentrated acid is then introduced into a regeneration furnace, where it undergoes thermal decomposition.

• Thermal Cracking and SO₂ Production

In the regeneration furnace, the concentrated acid is atomized by mixing with compressed air and heated to temperatures ranging from 1000 to 1200°C. This high-temperature environment causes the H₂SO₄ to thermally crack, following the reaction:

2H_2​SO_4​→2SO_2​+2H_2​O+2O_2​

As a result, sulfur dioxide (SO₂) gas, water vapor, and oxygen are produced.

• SO₂ Purification and Conversion

The resulting SO₂ gas is subjected to a purification process to remove impurities such as organic materials, metals, and ash. Following purification, the gas is dried by contact with weak sulfuric acid (93-96% H₂SO₄) in a packed bed tower. The purified and dried SO₂ is then fed into a contact vessel, where it undergoes oxidation to sulfur trioxide (SO₃) in the presence of a catalyst, typically vanadium pentoxide (V₂O₅).

• SO₃ Absorption and Acid Production

The generated SO₃ is subsequently absorbed in water or concentrated sulfuric acid, leading to the production of fresh sulfuric acid. In some cases, the SO₃ is first dissolved in oleum (fuming sulfuric acid) before being added to water. The final product is a high-purity, non-fuming sulfuric acid, with concentrations typically ranging from 93% to 99.2%, depending on the desired grade.

• Requires a regeneration furnace, gas cleaning units, catalytic converters, and absorption towers.
• Often includes waste heat recovery systems to improve energy efficiency.

Figure 1. Regeneration Furnace

Purity: These plants are designed to produce high-quality sulfuric acid that meets the stringent requirements of various industrial applications. Through a combination of pre-treatment, optimized process parameters, and the use of advanced equipment with corrosion-resistant materials, coupled with multi-stage purification techniques, we can effectively remove impurities and ensure the high purity of the final product in an environmentally friendly manner."

• Pre-treatment: This initial step involves removing or neutralizing impurities before the main regeneration process. Techniques like filtration, neutralization, and oxidation can be employed to target specific contaminants, such as suspended solids, organic matter, or inorganic compounds.
• Optimized process parameters: The efficiency of the regeneration process depends on carefully controlling factors like temperature, pressure, residence time, and acid-to-water ratio. By optimizing these parameters, we can maximize acid recovery and minimize impurity carryover.
• Advanced equipment with corrosion-resistant materials: Using high-quality equipment made from materials like stainless steel or specialized alloys can prevent corrosion and minimize the introduction of metallic impurities into the regenerated acid. This ensures product purity and extends the equipment's lifespan.
• Multi-stage purification techniques: A combination of purification steps, such as distillation, ion exchange, or absorption, can effectively remove a wide range of impurities. Distillation separates components based on their boiling points, while ion exchange can remove specific ions. Absorption can be used to capture certain impurities from the acid solution.

By carefully implementing these measures, we can significantly enhance the purity of the regenerated acid, making it suitable for demanding applications and minimizing its environmental impact.

Resource Efficiency: The process reduces dependence on raw sulfur.

Cost Savings: Operating costs are lowered by minimizing the purchase of new sulfuric acid and waste disposal costs.

Energy Efficiency: Waste heat recovery systems are incorporated to capture and reuse energy, thereby reducing overall energy consumption and costs.

Environmental Benefits: The plants reduce emissions of sulfur oxides and other pollutants, thereby contributing to a healthier environment and mitigating the effects of acid rain. They are also essential for industries to comply with environmental regulations that mandate the proper management and disposal of hazardous waste.

Conclusion

Spent acid regeneration plants are invaluable assets for industries that generate significant quantities of spent sulfuric acid. These plants offer a range of benefits, including resource conservation, cost reduction, environmental protection, regulatory compliance, energy efficiency, and sustainability. By effectively recycling waste acid, these plants play a vital role in promoting a more sustainable and environmentally responsible industrial landscape.