Dry Gas Seals Process parameters
Dry gas seal application on P2202 A / B pump
P2202 A / B Pump Introduction
P2202 A / B pump is the Sinopec Anqing branch of the fertilizer part of the low temperature methanol flushing device on the re-absorption tower circulating pump, the medium is rich in H2S methanol, equipment model: 10 × 12-21N, it is a horizontal single-stage pump, the use of mechanical seals. The process parameters of the pump are shown in Table 1.
Table 1 P2202 pump process parameters
P2202 A / B pump seal modification
P2202 A / B pump the original mechanical seal for foreign imports of mechanical seals, as shown in Figure 2. The sealing liquid is ethanol, because the process medium (methanol) contains more impurity particles (mostly due to pipe corrosion), making the mechanical seal of the friction side of the serious wear and tear, mechanical seal life is very short, often on the methanol pump Mechanical seal to replace, resulting in maintenance workload, high maintenance costs. In this case, in April 2008 the methanol pump mechanical seal to transform.
Figure 2 P2202 pump mechanical seal structure
Because the sealing liquid and the medium are easy to vaporize the material, and the media contains many impurities, the general mechanical seal is easy to have a negative impact, according to the pump process parameters and the actual conditions of the characteristics of the following two transformation program:
(Figure 3, Figure 4), so as not to be affected by the vaporization of the medium, and by the main seal (1) in order to overcome the medium volatilization caused by mechanical seal end of the dry friction, the main seal using dry gas seal, sealed type selection TM11A dry gas seal (Figure 3, The gas is filtered so that the dry gas is sealed by the end face of the clean gas.
Figure 3 P2202 pump dry gas seal structure diagram 4 P2202 pump dry gas seal control system
(2) In order to make the impurity of the medium do not affect the normal work of the dry gas seal, the front buffer is used for the flushing, in order to make the structure simple, directly using the pump outlet filter after the clean medium as a buffer, while the pump medium and seal Add a spiral seal between the buffer to block the impurity from entering the buffer and protect the dry gas seal from working properly.
The original shell on the various openings are also adjusted accordingly, the corresponding relationship shown in Table 2.
Table 2 Correspondence of enclosure openings
Dry gas seal work, the main seal gas pressure 0.7MPaG pipe network low pressure nitrogen, filtered by the filter, the gas filtration accuracy of 1μm, by the vertical pressure regulating valve, flow meter into the sealed cavity. In order to ensure the safe operation of the pump, when the pressure of nitrogen as low as 0.4MPaG, by the self-standing control valve installed after the pressure switch instrument control methanol pump interlocking shutdown.
Dry gas seal is the front of the buffer from the pump outlet pipe cited over the media liquid - methanol, filter the filter through the impurities contained in the particles, filled with dry gas sealed front buffer chamber to protect the dry gas seal The sealed end face will not be contaminated by the viscera medium.