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ANSYS > Case Studies > Process Improvement in Stable Bleaching Powder Reactor at Aditya Birla Science and Technology Company

Process Improvement in Stable Bleaching Powder Reactor at Aditya Birla Science and Technology Company

Technology Category

Sensors - Gas Sensors
Sensors - Utility Meters

Applicable Industries

Metals
Oil & Gas

Applicable Functions

Logistics & Transportation
Product Research & Development

Use Cases

Last Mile Delivery
Time Sensitive Networking

The Challenge

Aditya Birla Science and Technology Company was facing a significant challenge in their Stable Bleaching Powder (SBP) manufacturing process. The process involved the chlorination of hydrated lime by aerating an SBP solids bed with chlorine gas. However, the company was losing approximately 60 kg/batch of solids, which comprised of products, reactants, and intermediate compounds. These losses were resulting in significant time and cost inefficiencies. The goal was to minimize these losses without making major modifications to the SBP plant. The challenge was to identify process parameters that could be altered to improve the efficiency of the process. However, being a closed-loop system, onsite physical measurements were difficult to carry out.

About The Customer

Aditya Birla Science and Technology Company Private Limited (ABSTCPL) is the corporate research and development centre for the Aditya Birla Group. Located in Taloja, just outside of Mumbai in India, ABSTCPL supports the broad diversity of the Group’s businesses through multidisciplinary teams of expert scientists and engineers who lead fundamental and applied research projects. At ABSTCPL, research and development is based on two strong capabilities. The Process Engineering and Sciences Laboratory focuses on advanced processes and designs, process control and automation, and process engineering platforms and scale-up. The Science and Technology Platforms Laboratory provides expertise in metallurgy, fiber science and textiles, materials and surface sciences, and chemistry.

The Solution

The company decided to use ANSYS CFD to understand the existing issues in the flow patterns. The aerated solids bed was modeled as a porous zone, and impeller rotation was captured using the frozen rotor approach, with the k-ε turbulence model. Simulations helped identify gas channeling and regions where flow velocities exceeded the terminal settling velocity of the average solids particle size. The gas injection nozzle diameters and the number of injection locations were identified as the design parameters. Simulations revealed that increasing the nozzle diameter 2.5 times reduced the outlet-velocity-to-terminal-velocity ratio to 0.57 with 92 percent more uniform flow distribution. Adding two injection locations further reduced the velocity ratio to 0.47, but some flow uniformity was lost.

Operational Impact

The use of ANSYS CFX for simulations led to a more efficient and cost-effective solution for the SBP manufacturing process. The easy-to-use interface helped to run rapid, robust simulations from preprocessing to solving to post-processing in ANSYS Workbench. The optimum design was achieved without incurring any physical testing costs and consequent plant downtimes. A more uniform chlorine gas distribution inside the reactor will reduce the SBP batch time. Increased process sustainability could reduce current EHS issues. Since chlorine gas tends to corrode metals, a more uniform distribution of chlorine within the reactor will reduce the excess chlorine required for reactions, thereby improving reactor lifetime.

Quantitative Benefit

Reduced the outlet-velocity-to-terminal-velocity ratio to 0.57 with 92 percent more uniform flow distribution after increasing the nozzle diameter 2.5 times.
Further reduction in the velocity ratio to 0.47 after adding two injection locations.
Significant reduction in the loss of solids per batch, leading to major time and cost savings.