SU846403A1 - Device for automatic control of adiabatic desalinating unit - Google Patents

Description

one

The invention relates to shipbuilding, in particular, to devices for the automatic control of a desalination adiabatic installation.

A device is known for automatically controlling a desalination and adiabatic plant, including drivers and capacitors, comprising a flow sensor and a control valve, JQ installed in the sea water path, a control unit connected to the first input with a flow sensor, and an outlet with a control valve, and seawater temperature controller

The disadvantage of this device is that it does not provide sufficient control of the desalination process when the scientific research institute is between adjacent ones in series. the steps of the evaporator chambers are turned on, which makes it insufficiently economical. .

The purpose of the invention is to increase the efficiency of the desalination plant by improving the control accuracy.

This goal is achieved by the fact that the device is equipped with a differential pressure sensor, the first input of which is connected to the evaporator of the first stage, the second input to the evaporator of the last stage, and the output to the second input of the control unit.

The drawing shows a functional block diagram of the device.

The automatic control device consists of a flow sensor 1, a pressure differential sensor 2, a control unit 3 and a regulator 4. At that, the control unit 3 is connected to its first input with a flow sensor 1, the second input is connected to a pressure differential sensor 2, and output - with regulator A. This device is connected to an adiabatic desalination plant (for example, a three-stage) "consisting of evaporation chambers 5-7, capacitors 8 built in them, and 9 collectors of distillate, preheater 10, pumps 11-13 accordingly , Distillate, brine and sea water (nutrient), an ejector 14, steam mixture. The collectors 9 of the distillate are hydraulically connected by pipelines 15. The desalination plant also contains a controller 16 for seawater temperature at the inlet to the evaporators and by-pass devices 17 hydraulically connected in series to the evaporators 5-7. The differential pressure sensor 2 is connected to its first (positive) input with an evaporator 5 of the first stage, and the second input with an evaporator 7 of the last stage of the desalination plant. The mechanisms and apparatus included in the installation are connected by pipelines,

A device for automatically controlling the process of desalination of seawater in an adiabatic desalination plant operates as follows.

The desalination sea water is pumped by the feed pump 13 through the condensers 8 of all evaporators 5-7, starting with the evaporator 7 of the last stage, in which the pressure (vacuum) is successively lowered from the first stage to the last. The vacuum in the evaporators is created by the ejector 14, which sucks the vapor-air mixture from the evaporators. In condensers 5, the seawater is heated by transferring heat to the condensing vapors, and in heater 10 it is heated by coolant passing through the regulating orpan of the seawater temperature regulator 16 to a temperature higher than the saturation temperature corresponding to the pressure in the evaporator 5 of the first stage.

As a result of overheating of the seawater in the evaporator of the first stage, it boils and part of it evaporates, and the other part has cooled down to a temperature corresponding to the pressure of saturated vapor in this stage, due to the pressure difference through the bypass 17 to the evaporator 6 of the next stage. The same process is repeated in subsequent stages, since the pressure in each of them is lower than in the previous one. Water vapors are condensed in condensers 8 and the distillate flows into collections 9 of distillates, from which, due to the pressure difference in the chambers, flows through pipelines 15 into the collection of distillate of the last stage evaporator and is pumped out of it by distillation pump 11 to the consumer. The brine from the evaporator 7 is pumped out with the brine pump 12. During the period when the desalination plant is put into operation, the vacuum in the evaporators is created gradually as the air is drawn out of the nickname. Initially, in the absence of a pressure differential between adjacent evaporators, the consumption of WATER through the bypass devices 17 is minimal. With the development of vaporization between evaporators, pressure drops are created, and the water flow through the bypass devices gradually increases, reaching its maximum value in the operating mode of the desalination plant. The flow rate of seawater (capacity of the pump feed pump 13) is measured by the flow sensor 1, and the pressure differential between the evaporators 5 and

7 first and last steps - dates | Chick 2 differential pressure. Date signal; chi a} flow is supplied to the first

the input of the control unit 3, and the correction signal of the differential pressure sensor 2 is fed to its second input.

8, block 3, the control signal of the flow sensor i is compared with the reference signal of the control unit 3 and the correction signal of the differential pressure sensor 2 and when the measurement circuit is unbalanced, the control unit 3 generates a control signal that changes the capacity of the nutritional signal to the corresponding value 4 site 13 and the flow of sea water entering the evaporator 5 first step. At. This device maintains the performance of the feed pump 13 equal to the flow rate of water through the bypass devices 17 at a given value of the pressure differential between the evaporators. The magnitude of the supported capacity of the feed pump, set by the reference signal of the control unit 3, should be minimal, not exceeding the magnitude of the water flow through the bypass devices in the absence of a pressure differential between the evaporators.

As the evaporator develops and seawater boils, the pressure drop measured by sensor 2 appears and gradually increases.

Claims (1)

Claim. A device for automatically controlling a desalination adiabatic installation, including evaporators and condensers, containing a flow sensor and a control valve installed in the sea water path, a control unit connected to the first input to the flow sensor, and the output with a control valve, and a sea water temperature regulator, characterized in that, in order to increase the efficiency of the desalination plant by increasing the accuracy of control, it is equipped with a differential pressure sensor, the first input of which is connected to the evaporate the first stage, the second input - with the evaporator of the last stage, and the output - with the second input of the control unit.