The main function of the
condenser is to condense the steam part of the mixed gas above 100 ℃ from the
vacuum tank into the liquid below 25 ℃ at one time, so the cooling capacity
should be particularly strong, and the condensation effect should be
particularly good. Generally, the condensation power shall be more than 3 / 4 of
the rated power (i.e. evaporator power) of VPD equipment.
The structure
of the condenser is a shell and tube heat exchanger. There are many baffles in
the shell side of the air flow to ensure that the air flow can be fully
condensed. The total water inlet and outlet pipes are divided into several
branches in the condenser to form enough condensation area. Due to the large
amount of cooling water, VPD equipment needs to have a special cooling water
station or chiller to supply circulating cooling water.
The temperature
of cooling water has a great influence on the performance of condenser. The
lower the water temperature is, the stronger the water catching capacity is, and
the lower the partial pressure of water vapor in the residual gas after
condensation is. Generally, the maximum partial pressure of water vapor that the
leakage pump can bear is about 3kpa, and the corresponding saturation
temperature of water vapor is 24 ℃. That is to say, the temperature of the oil
water gas mixture at the outlet of the condenser should not exceed 24 ℃,
otherwise, too much water vapor will enter into the leakage pump, affecting its
normal work; and the temperature of the cooling water needs to be lower, which
is difficult to guarantee in many areas of China in summer. In recent years, in
order to effectively enhance the condensation effect, the main condenser of
existing VPD equipment is cooled by a water chiller, or a small condenser with
cooling water provided by the water chiller is connected in series between the
collection tank and the leakage pump to further reduce the partial pressure of
water vapor and kerosene vapor in the residual gas.
The working pressure
of the condensing system is also very important. It is obvious that if the total
pressure in the condenser and the collecting tank is lower than the saturated
vapor pressure of water at that time, the water vapor is impossible to condense
at all and will be pumped out by the drain pump. In order to fully condense the
water vapor, the condensing pressure must be higher than the saturated vapor
pressure. However, the pressure of the condensing system should not be too high.
Because the pressure of the condensing system is too high, the gas pressure in
the vacuum tank is required to be higher. Otherwise, the mixed gas cannot flow
into the condenser naturally under the effect of the pressure difference, and
the high pressure in the vacuum tank will directly affect the outward diffusion
of water vapor in the insulating material. In consideration of the above two
factors and the presence of permanent gas components in the residual gas, the
working pressure in the condenser is selected as 4.5kpa, which can not only
ensure the sufficient condensation of water swallow gas, but also make the
pressure in the vacuum tank as low as possible
In the VPD equipment,
there is also an auxiliary condenser in the condensation system, which is
specially used to receive the high-temperature kerosene vapor discharged in the
later stage of the kerosene purification process in the distillation chamber.
The structure of the auxiliary condenser is the same as that of the main
condenser. The power of the condenser corresponds to the power of the
distillation chamber, and the condensed kerosene liquid is also discharged to
the collection tank.
Dry Type
Oilless Vacuum Pumps Dry
Scroll Vacuum Pump SSR Roots Type Blowers
