Technical characteristics of special hydrophobic control valve for alumina

Technical characteristics of special hydrophobic control valve for alumina

April 29, 2019

In the alumina production process, the steam trap is the key valve in the high pressure dissolution production. In the past, due to the large volume of the alumina hydrophobic level control valve, the temperature control adjustment requirement is high.

The alumina hydrophobic level control valve is a key process device transformed by high-pressure steam catalytic medium. The working condition is tough, that is, the strength of the valve and the sealing surface are not damaged by cavitation, and the high-pressure steam is passed through the resistance-enhanced diffusion and flashing. The desired temperature saturation is achieved to enhance the conversion of vapor-converted condensate and to increase the effectiveness of alumina in high pressure steam + alkali materials. Moreover, the special hydrophobic level control valve for alumina has different adjustment parameters at different positions of the working condition, and the feeding temperature is generally between 130 degrees and 380 degrees. The pre-valve pressure is 3.1 MPa to 4.0 MPa, and the post-valve pressure is 0.2 MPa to 2.4 MPa.

At present, in the case of domestic similar traps (high pressure steam + alkali material), the traps currently used are ordinary regulating traps + threaded orifice plates to discharge the precipitated alkali materials, and the orifice plate type is installed due to the inlet port. The filter, while overcoming the problem of clogging, increases the amount of hydrophobicity, but the orifice trap is only used in steam systems with lower flow rates. However, for the special working conditions of alumina and the solid medium with high hardness, the valve can only be stopped due to the valve blockage, and the pressure difference between the inside and the outside of the valve can be opened before the screw plug can be opened, and the sewage discharge effect is poor. The conversion rate of steam conversion to condensed water and the adjustment of valve opening degree of the existing hydrophobic level control valve can generally only be judged by the experience of the operator, and there is no scientific and effective detection means for the position of opening or closing of the valve and the steam conversion rate.

The flasher water injection method of the alumina autoclave dissolution system injects the high-temperature condensed water of the preheated high-pressure end condensate water tank into the seventh-stage and eighth-stage flash evaporators and simultaneously washes the sedimentation in the alumina autoclave dissolution system The liquid is injected into the ninth and tenth-stage flashers; and in the case where the primary washing liquid in the alumina autoclave dissolution system is not smooth or there is no sedimentation, the condensed water of the bad water condensate tank can be simultaneously It is injected into the ninth and tenth-stage flashers by the pump; when the operating pressure of the flasher of the alumina autoclave dissolution system is low or the material is charged, the high-temperature condensed water from the evaporator can be simultaneously injected by self-pressure. Go to the ninth and tenth grade flashers.

Since the high pressure dissolution reaction cooker section needs to heat the slurry 200 ° C to 260 ° C with 6 MPa of new steam, this process will consume about 90 tons of new steam per hour, and will produce about 90 tons of high pressure and high temperature condensate through a pneumatic control valve. Sprayed into the condensate flash tank to obtain steam and low temperature below 6MPa, so the choice of steam trap is crucial.

Features of the special steam trap for alumina:

  • The original orifice plate hydrophobic structure is improved to a damper plate structure. The damper plate structure can generate multi-stage damping capacity expansion and enhanced expansion effect through the change of internal structure. The improved damper plate type steam trap can precipitate larger particle material through the circular small hole of the damper plate, and pass the pure steam as much as possible. The damper plate enters the valve chamber to increase the resistance of the high-pressure steam to increase the conversion rate of the high-pressure gas inside the valve. The high-pressure vapor will enter the valve and collide with the damper plate from the inlet, and then a part of the vapor bypasses the damper plate from both sides of the damper plate. After the collision with the rear side of the damper plate, the steam has energy consumption during the collision, which increases
  • the conversion rate of steam to condensed water. As shown below.
  • Unique three-time increase resistance expansion and secondary flash evaporation effect. In addition to the one-time increase and expansion expansion of the damper plate, the new steam trap is designed to increase the resistance at the secondary valve seat. When the high-pressure steam passes through the sealing surface of the valve seat and the valve seat, it will produce a third increase in resistance. Expansion; three-stage increase in resistance and expansion has slowed the vapor pressure and achieved diffusion and eased the source of cavitation. In addition, the structure of the new steam trap is designed with a valve flap secondary flashing zone. The effect of converting the high pressure steam into condensed water through the flash structure is better, which not only reduces the damage of the sealing surface caused by cavitation, but also improves the valve. Service life. As shown below.

In summary: the alumina hydrophobic globe type control valve has the characteristics of anti-cavitation and anti-solid liquid leakage. Compared with the regulating valve used in petrochemical and electric power conditions, the volume is large, and the production and processing are difficult; The item has high value-added and high-precision high-tech valve products.