Solidaire | TorusDisc
The Executive Summary
We delivered a drying system as part of the process to create the base for cosmetic products.
The client was shipping product between facilities halfway through the drying process because they couldn’t get both stages done in one place.
We helped fix that and more.
Additionally, while building the system, we produced multiple tonnes of product for them every month so they could get to market more quickly.
Since then they’ve bought another line of the same system at twice the size. They’ve also come back to us for multiple drying opportunities because they know we have a wide breadth of capability and we’re able to provide a quick feasibility evaluation and recommendations.
Our process differed from what they were using because it:
Got the entire process done in one facility
Used less nitrogen
Used less horsepower
Took up drastically smaller footprint
Had a higher ability to control the moisture content
Produced a higher quality, higher purity end product with guaranteed product quality levels
We like a challenge.
We love the corner cases, the atypical projects, and doing things other firms can’t. That’s why we’re showcasing this project.
We delivered a drying system to a specialty chemical manufacturer that creates the base for cosmetic products. The raw material consisted of a base solid dissolved in a solvent. This base is a fine, pure white powder that needs to have as few impurities as possible. The presence of a solvent in the raw material required special consideration when approaching it with thermal technologies.
Their in-place drying process presented numerous challenges. The client was using two tollers across multiple facilities. Neither facility could complete the entire process, they weren’t as efficient as they could be, and the added handling steps increased the risk of black speck impurities in the final product. This solution resulted in inefficient drying, lengthy material handling, and an imperfect end-product.
The client wanted to bring their drying process in-house, but neither of their two tollers could provide a system that completed the entire process under one roof.
Let’s dig deeper into how the client handled the process, then see how we approached it.
A problem in need of solving.
They took raw material from their plant and shipped it to a toller, who processed it through a spray dryer to remove moisture. Spray dryers primarily operate in a direct thermal process, meaning the heated gas stream (typically oxygen) is in direct contact with the material to be dried.
Due to the presence of a solvent, the spray dryer could not use the more cost-effective heated air as the heat-transfer fluid. Instead, they opted to use a large, heated nitrogen stream, demanding an equally large operating expense. The volume of heated gas required high-horsepower blowers, further adding to the inefficiency of the solution.
Though the initial spray drying process removed a bulk of the moisture, the material’s moisture diffusion rate meant it couldn’t finish the job alone. They had to ship the partially finished product to another toller who used a batch drying process to get the product to the final required moisture of <20PPM.
And now they can efficiently process their material under one roof at a higher product quality.
Here’s how we did it.
The search for a solution.
We started discussions with the project engineer and their lead North American tolling engineer to better understand the client’s needs. We conducted a bench test with their raw material to evaluate their application and help propose a solution.
Given the necessity to remove a solvent, we immediately ruled out any of our direct thermal processes. Instead, we investigated using an indirect thermal process. Indirect thermal processes employ a barrier/surface between the thermal media and the material to be dried.
An indirect method drastically lowers the risk of explosion when handling volatile materials and requires far less gas than a direct process, reducing your overall utility cost and the size of downstream condensation components.
Knowing that we were investigating indirect technologies, we were able to tailor a bench testing program to evaluate the feasibility and begin making process assumptions. After receiving their feed samples, we performed two primary tests for evaluation. The first test evaluated the material's tendency to stick along a temperature gradient. That data helped us determine where the transition phase occurs and what conveyance challenges we may face in the pilot demonstration.
The second test develops a drying curve for their material. This plots the time-temperature correlation and informs us of when we can expect to get into the diffusion limited moisture requiring higher temperature or longer residence times.
Good news:
This process helped us see that the project is feasible and we can design a two-stage drying system to get it done.
Designing the perfect fit.
With the right Bepex equipment and a custom system design, we created a one-facility process for the client.
We took our findings from the bench evaluation and began designing a system for pilot scale evaluation.
The proposed system included our Solidaire Paddle Dryer for the initial drying step, our TorusDisc Dryer to provide the residence time necessary for the diffusion limited moisture, and a second Solidaire to cool the dried material prior to packaging.
The Solidaire consists of a single horizontal rotor with adjustable paddles running the length of the vessel. The vessel utilizes a jacketed design to allow for various thermal media, including steam and hot oil for heating or chilled glycol or water when using the Solidaire as a cooler.
Material to be processed is dispersed into a thin layer along the vessel wall, maximizing the heat-transfer coefficient while allowing the design to handle difficult material transitions.
The TorusDisc consists of one or two jacketed rotors mounted inside a jacketed vessel. The material forms a bed in the dryer, which is agitated by the rotating disc rotors.
A discharge weir controls the bed height and residence time. Given the ability to condition the rotor walls as well as the vessel, the TorusDisc offers a high amount of heat transfer surface area in a more compact footprint.
Here’s how it works:
The first Solidaire receives the liquid feed with dissolved solids via a pump. The paddle-rotor design provides the mechanical means necessary to work through the material transition phase, as it transforms from a liquid to a free-flowing solid. A small heated nitrogen stream runs counter-current to the flow of material, picking up and carrying the evaporated solvent to the condensing system where the solvent is safely recovered.
The TorusDisc is mounted directly after the first Solidaire and receives the partially dried solids. During pilot trials, we fine-tuned the exact residence time required to reduce moisture levels to < 20 PPM.
The dried solids pass through another Solidaire. This time it uses chilled glycol in the jacketed vessel to help cool the solids ahead of downstream packaging.
Throughout this whole process, the major stakeholders on the client’s side were on site, giving us instant feedback on if the product was up to their standards. While running the product, we continually optimized the operating conditions to yield the best product quality possible.
Our process differed from what they were using because it:
Got the entire process done in one facility
Used less nitrogen
Used less horsepower
Took up drastically smaller footprint
Had a higher ability to control the moisture content
Produced a higher quality, higher purity end product with guaranteed product quality levels
Let’s see the results.
While we built and installed a system to meet their commercial requirements, we produced multiple tonnes of product for them every month so they could get to market more quickly.
We also gave them guaranteed rates and moisture levels to align with product quality expectations so they can be sure they can trust the system.
Since working with us, they’ve purchased a second line of the same system twice the size of the first. They also come to us for several different drying system needs outside this initial application, knowing we can provide a quick feasibility evaluation and recommendations.
Work with us.
We’re the material transformation people.
Bepex can solve any processing needs you have. We’ll design and build a custom system suited to your unique application and ensure your product is made efficiently with high quality standards.
Let’s build your system.
