Project Synopsis
Develop a scaled up stripping column to recover chloramine and an absorption column to concentrate the recovered chloramine in water for a pilot scale facility working to develop an efficient process to devulcanize rubber from used tires and recover the carbon black, rubber, steel, etc.
Project Summary
The client owns and operates a pilot-plant facility that supports process development efforts to devulcanize rubber from used tires and recover the carbon black, rubber, and steel. The client was considering expanding the process to include a stripping column to recover chloramine from liquid effluent from their primary reactor and an absorption column to concentrate the recovered chloramine in water. The water stream was to be recycled back to the reactor. This recycle step improves the overall efficiency and economics of the overall process. While the client had some laboratory data, they were not confident in the design of these two major unit operations and requested Process Engineering Associates, LLC (PROCESS) validate this portion of the plant design. Further, PROCESS was asked to optimize these two columns, scale up the size for a larger unit, and develop equipment specifications the proposed equipment.
PROCESS reviewed the available information, laboratory data, and pilot-plant operating parameters which the client process design was based upon. PROCESS then performed a literature search to find vapor-liquid-equilibria (VLE) data on chloramine mixtures with air and water. The concentration of chloramine in the various streams is dilute, less than one percent by volume. The literature search resulted in locating a Henry’s law constant that when back tested against empirical data proved a reliable estimate of vapor-liquid phase conditions.
With the gathered information tabulated in a design basis, PROCESS developed a simulation model of the absorber and stripper columns in CHEMCAD. This model consisted of the major process and utility streams with flow rates, compositions, temperatures, pressures, and physical/chemical properties. A Process Flow Diagram (PFD) was also developed. Process conditions predicted by the model were reviewed and accepted by the client’s project team.
The CHEMCAD model and the initial results generated were used to optimize the two-column configuration. After several iterations and review cycles with the client, an approach was devised that could effectively remove chloramine from the reactor effluent while also cycling up the water stream effluent from the absorber such that it could be efficiently recycled to the reactor.
Optimized performance results were then used to size the columns. The resulting specification included column diameter and height, nozzle sizes and locations, packing height, and liquid distributor specification. PROCESS worked with a third-party packing supplier who provided guidance on HETP and other service parameters such as flooding and wetting rate.
As of the writing of this document, the client has purchased and installed the columns in their pilot facility.
Industry Type
Tire Recycling
Utilized Skills
- Process design information evaluation
- Distillation design
- Process design.