NASA-LLIS-0201

Abstract

<strong>Description of Driving Event:</strong> <br>The full-scale ASRM propellant manufacturing facility may not be directly scaleable from the continuous mix pilot plant. Particular problem areas relate to the particle size of the propellant and the screw pump section of the rotofeed. <br>Many parameters and processes for the new facility have not been fully determined. However, another manufacturer has produced a substantial amount of similar solid propellant using continuous production processes, so the basic techniques are familiar. <br>Safety devices are installed on the propellant flow line to limit the spread of fire in case of an accident. The flow line transporting the uncured propellant has several firebreaks to prevent propagation of a fire along the tube. The basic safety device is an explosive-fired guillotine valve that interrupts the flow, with a water spray on the propellant to lower the temperature below the ignition point. In addition, there is a collar in the flow line upstream of the guillotine and on the casting pit side of a firewall that can be blown to allow the propellant to flow out on the floor and prevent pressure buildup. A matter that must be considered is cleanup after an accident involving a dump of uncured propellant on the floor. The continuous mix pilot plant at manufacturer provides a way of proving a new propellant and upgrading the equipment before establishing a full-scale facility at yellow creek. The major differences between the pilot plant and the full-scale facility are equipment size and process control software. The pilot plant production rate is 1,000 to 1,400 pounds/ hour with the full-scale facility producing 20,000 to 26,000 pounds/hour. The ultimate particle size of the propellant is dependent on parameters such as geometry of piping, length of lines, and fluid working pressures that may not be directly scaleable. There are many challenges such as metering of propellant solids, pre-mix of iron oxide and aluminum, and real-time process control. Upscaling the rotofeed dearator and pump equipment probably presents the greatest challenge.