Shutdown procedures on Mixers, Crutcher and Pumps - Essay Example

Order 515277 Topic: Shutdown procedures on Mixers, Crutcher and Pumps The mixer combines all liquid powder or solid constituents of a soap formula with speed and effectiveness. When a continuous process is in use, ‘the process is shut-down by firstly closing the supply of water and alkali to the mixer. The supply of succinic anhydride is allowed to continue until all water and alkali has been flushed through the mixer then this supply is also shut-down. This procedure ensures that no hydrolysis continues in the mixer whilst not in use.

Preferably not all of the succinic acid is flushed through the buffer tank. This means that when the supplies of succinic anhydride, water and alkali are switched on for start-up, there is still some acid in the buffer tank to "seed" the hydrolysis reaction. During the period that the process is not operating, the buffer tank should be maintained at an elevated temperature (typically 60°-80° C.) in order to prevent solidification of the succinic acid/anhydride mix’ (Patentstorm 1998). A crutcher is the ‘main reaction vessel in the semi-boiled saponification process, or simply a mixing vessel in the soap modification process.

It can be used to make a wide variety of soaps or for mixing additives and fillers into liquid soap. Crutches are very easy to use and are generally found in laundry soap factories. They are also used in more sophisticated plants, such as for making transparent soap. A process is described for retarding or preventing the setting of a miscible and pumpable crutcher slurry intended to be spray dried to base beads for subsequent conversion to a built synthetic organic nonionic detergent composition.

The slurry, which contains described proportions of water softening zeolite, water soluble salt(s), including sodium bicarbonate and sodium carbonate, and a swelling bentonite, sometimes sets up in the crutcher in which it is being prepared. Often such solidification is spontaneous after the bentonite has been added to the crutcher, and sometimes occurs only minutes after such addition. When 0.5 to 5% of magnesium sulfate is incorporated in the crutcher mix such undesirable setting of the mix is delayed or prevented entirely, and crutching times of at least one hour (and sometimes appreciably longer) are attained, after which the crutcher slurry is still miscible, and is pumpable to a spray drying tower.

In addition to sodium bicarbonate and sodium carbonate the crutcher mixes may also contain sodium sesquicarbonate (sometimes at least partially in replacement of the bicarbonate and carbonate), sodium sulfate and small amounts of sodium silicate, with the proportion of sodium silicate being no more than 2% of the crutcher mix, and desirably being nil. No citric acid or citrate is required to help maintain the fluidity of the crutcher slurry and citric materials are omitted from the crutcher mixes’ (Saar, & Mead 1985).

On the other hand, ‘shutdown procedure for pumps include releasing or admitting air to a pump with a hot boiler, especially when it is under vacuum, permits a strong fluid and greatly increases the risk of an explosion. When boiler temperature reaches F (C) it can cause serious burns. Always check that surfaces have cooled to near room temperature before touching them. To shutdown the pump, close the inlet valve on the system, if equipped. Turn off the power to the heaters. For pumps equipped with the optional quick cool coil, admit water into the coil.

Continue to flow cooling water through the pump (and quick cool coil, if equipped) for at least the time period allowed. Once the pump is cooled, shut off the mechanical backing pump. Air release the pump. Continue cooling water flow until the pump is at room temperature, then shut off the water supply’ (Ehmann, 2010). References Ehmann, J2010, ‘HS-20 diffusion pumps for GVE coating systems’, Agilent Technologies, Varian, Inc, USA. Patentstorm 1998, Process for manufacture of a high active detergent composition containing succinic acid, accessed 28 March 2011,