API Equipment Sprays
More than 20 years ago ESC modified standard ESC Ball, Bubble and Tube sprays for a process being developed to manufacture high-potency agricultural products via a process run in solvents. Some experimentation proved the ability to remove soils accumulated during production runs of 7-12 weeks, with a water based CIP program using both alkaline and acid solutions for soil removal, by spraying vessels and pressure washing pipelines. A Single-Tank Single-Use CIP Skid fitted with a powered strainer in the CIP return line enabled all CIP operations to be accomplished with a small batch of solution, subsequently incinerated. CIP was applied both to assure effective cleaning, and to protect the environment. This story was part of the subject of Clean-In-Place for the CPI (Chemical Process Industry) published in CHEMICAL ENGINEERING by J.C.Stewart and Dale A. Seiberling in January 1996. About four years later Seiberling was invited to share the experiences with an industry-wide group of API manufacturers The presentation titled Some Comments on the Application of Validatable CIP to the API Process: Constraints, Components, Concepts and Criteria opened the door to many subsequent projects. In February 2002 CHEMICAL ENGINEERING published Making the Case for Clean-In-Place by G Cerulli and J.W. Franks.
The 1992 agricultural chemical process and the 2002 API process involved nearly identical types of equipment, methods, materials of fabrication and operating and cleaning requirements. Rather that 316L StSt the product contact surfaces were in the form of glass-lined vessels, Teflon lined piping, and metallic components in the form of valves, screens, pumps . . . and SPRAYS . . . fabricated of Hastelloy. The sanitary clamp-type joint in use for CIP since the early 1950s was replaced with ASME bolted flanges. However, the general CIP cleaning criteria for flow. pressure, and temperature were similar to those applied for five decades in dairy, brewing, wine production, many segments of food processing, and in the developing biotech industry.
Hastelloy Spray Ball
The standard ESC ball spray, 2-1/2″ in diameter, directionally drilled, made of hastelloy and installed in a flanged glass-lined tank head nozzle met the basic needs for vessels. The inability to add nozzles to glass lined vessels, and the complexity of overhead ductwork and piping, fabricated of Teflon lined pipe, was successfully addressed with bubble-sprays (shown at left), and tube sprays, of many variation in design and coverage requirements. These sprays can all be permanently installed and left in place during all production operations.
Typical Reactor Spray Application Example – The schematic diagram at the right below illustrates a reactor with an overhead vertical condenser, pipng, vapor riser and ductwork. A combination of ball sprays, bubble sprays and tube sprays were installed and supplied with CIP flush, wash and rinse solutions directed to this vessel via a dedicated line for Process Fluids and CIP controlled by eight (8) valves as follows:
(1) This valve supplied the CIPS piping dedicated to the vessel from which all other sprays are supplied. The process Product Supply header would be used for both process and CIPS fluids.
(2) This valve supplied a fixed ball with an extension arm and bubble under the manway cover designed to provide coverage of approximately half of the glass lined vessel.
(3) This valve supplied a fixed ball in the top of the condenser, covering the upper head,and sidewall and flooding the tube-sheet with sufficient liquid to provide the equivalent of 2 Gpm/Foot of circumference to all of the tubes.
(4) This valve supplied a tube with bubble spray for coverage of the bottom tube sheet and condenser sidewalls. All return flow from the condenser was to the vessel.
(5) This valve supplied a second ball spray on the opposite side of the vessel from the manway.
(6) This valve supplied a tube with four (4) bubbles installed in the top of the vapor riser. Holes drilled nearly adjacent to the flange (not shown) provided sidewall coverage for the large diameter riser. The bubbles on the tube provided coverage of the upper areas of four (4) horizontal runs from the riser to the condenser, rupture disc, process vacuum system, and process vent system. The bubble on the bottom end of the tube provided coverage of the riser, at a flow rate equivalent to 2.0 Gpm/foot of riser circumference.
(7) This valve supplied two bubble sprays in an Instrument Flange in the large diameter vapor riser, primarily to cover the instrument sensor wells and probes.
(8) This valve supplied two bubble-sprays spaced 180 degrees in an Instrument Flange at the very top of the Solids Addition Chute.
For most application of this type, the circuit design flow rate would be based on the requirements of the vessel. Valves 1 , 2 and 5 would generally be left open full time and for perhaps half of each minute, the other valves would be cycled to wet and flush all surfaces of the other components. All return flow was to the vessel, and from the vessel to the CIP source. In many early systems, lacking any automated CIP Skid, the vessel was the only puddle in the circuit, water and cleaning chemicals being added directly, and the process water supply was used as ths source of flush and rinse water thence discharged to facility waste via the dedicated vessel transfer pump. The discharge process header would simply be connected to the supply process header in the tank connection room to include piping to and from the vessel in the circuit.