Automatic PH control device for deaerated water of catalytic device deaeratorTechnical Field
The utility model relates to an automatic control device, concretely relates to catalytic unit oxygen-eliminating device oxygen-eliminating water PH automatic control device.
Background
At present, oil refining companies are more and more, the scale is larger and larger, and large boilers and various steam generators are applied more and more widely in various refining enterprises. The boiler is a device for producing steam and hot water, and the quality of water used by the boiler has great influence on the safe operation and efficiency of the boiler. Therefore, certain requirements are put forward on the quality of the boiler water and the quality management, and the qualified treated water is used as boiler feed water, so that the boiler can be safely and economically operated. The ph value is an important index, and the change of the ph value directly influences the safe and economic operation of the boiler equipment. The water quality standard of the low-pressure boiler added with liquid medicine in the boiler or chemical water outside the boiler is adopted in the steam boiler and the hot water boiler, the PH value is more than 7 and the boiler water is 10-12, and under the normal operation condition of the boiler, the pH value of the boiler water is higher than that of the feed water due to continuous evaporation and concentration of the boiler and decomposition of certain salts. At this time, a layer of compact ferroferric oxide protective film can be formed on the surface of the metal. This is very advantageous for corrosion protection of boiler surfaces. The pH value of the pot water is regulated to be between 10 and 12. The boiler operation is guaranteed. However, due to various factors, the pH of the furnace water is higher or lower. This poses a hazard to the safe operation of the boiler plant, which must be prevented to avoid accidents. When the pH value of the pot water changes to be less than 7 and free carbon dioxide exists in the water, the contacted metal is formed and electrochemical corrosion taking the carbon dioxide as a depolarizer occurs. The water supply and return pipeline system can also generate acid corrosion and the corrosion speed of ferrous metal. Obviously increased and more serious corrosion consequences. When the pH value in the boiler water is more than 13, the ferroferric oxide protective film generated on the surface of the metal is dissolved to generate iron salt, and after the film is dissolved, the alkaline corrosion speed is rapidly increased, and salt and scale are deposited on the tube wall of the furnace tube, so that accidents are caused. For boilers above medium and high pressure, the feed water should be maintained at a pH of 8.0 or above to prevent corrosion of the feed water system. Preferably 9.0 to 9.2. However, it is impossible to meet the requirements of various water-using facilities due to the requirements of production processes and the like and in consideration of investment costs. In addition, in the production, the water coming from the deaerator contains desalted water and condensed water, and the factors influencing the pH value are more, such as ion exchange resin and oil pollution of a condensed water system, so that a technological measure is needed to solve the problem of large pH fluctuation of boiler water supply water so as to ensure the safe operation of a boiler system and an air pressure unit.
Disclosure of Invention
The utility model aims at providing a catalysis device oxygen-eliminating water PH automatic control device aiming at the defects existing in the prior art.
The technical scheme is as follows: the automatic PH control device for deaerated water of the catalytic unit deaerator comprises an ammonia water dosing tank, a gate valve, a dosing pump, a deaerated water pump, a pH online monitor, a boiler drum, a steam generator, a deaerator and a frequency converter, wherein an outlet at the bottom of the ammonia water dosing tank is connected with an inlet end of the dosing pump through a first gate valve pipeline, an outlet end of the dosing pump is sequentially connected with one end of a fourth gate valve and an inlet end of the deaerated water pump through a second gate valve and a third gate valve pipeline, the other end of the fourth gate valve is connected with the deaerator, and an outlet end of the deaerated water pump is sequentially connected with the boiler drum and the steam generator through a fifth gate valve and a sixth gate valve pipeline; the dosing pump is electrically connected with the output end of the frequency converter, the control end of the frequency converter is electrically connected with the pH on-line monitor, and the sampling electrode of the pH on-line monitor is arranged on a pipeline between the fifth gate valve and the sixth gate valve.
And the first gate valve to the sixth gate valve are all manual valves.
The pH on-line monitor is an industrial pH analyzer.
And a sampling electrode of the pH on-line monitor is arranged on a pipeline 20-30 meters away from the outlet end of the deoxygenation water pump.
Compared with the prior art, the utility model, have following advantage: reasonable in design, simple structure, easy manufacturing, it utilizes industry PH on-line monitoring appearance, and the PH that in time discovers the deoxidization water changes, combines aqueous ammonia dosing pump automatic frequency conversion control for aqueous ammonia charge device to add the dose, makes the pH value of deoxidization water stable at qualified interval, solves the pH value of deoxidization water feed system and changes the subacidity corrosion scheduling problem that causes because of the pH value. Meanwhile, the PH values of the feed water of each boiler drum and each steam generator are stabilized, the control of boiler water indexes is facilitated, boiler accidents caused by large fluctuation of the PH values of the boiler water, poor quality of the boiler water and the like are avoided, and the safe operation of production is guaranteed.
Drawings
Fig. 1 is a schematic structural diagram of an embodiment of the present invention.
Detailed Description
Referring to fig. 1, a catalytic unit deaerator deaerated water PH automatic control device comprises an ammonia water dosing tank 7, a gate valve, a dosing pump 8, a deaerated water pump 9, a PH on-line monitor, a boiler drum 11, a steam generator 12, a deaerator 10 and a frequency converter 13, wherein a tank bottom outlet of the ammonia water dosing tank 7 is connected with an inlet end of the dosing pump 8 through a first gate valve 1 pipeline, an outlet end of the dosing pump 8 is sequentially connected with one end of a fourth gate valve 4 and an inlet end of the deaerated water pump 9 through a second gate valve 2 and a third gate valve 3 pipeline, the other end of the fourth gate valve 4 is connected with the deaerator 10, and an outlet end of the deaerated water pump 9 is sequentially connected with the boiler drum 11 and the steam generator 12 through a fifth gate valve 5 and a sixth gate valve 6 pipeline; the dosing pump 8 is electrically connected with the output end of the frequency converter 13, the control end of the frequency converter 13 is electrically connected with the pH on-line monitor 14, and the sampling electrode 15 of the pH on-line monitor 14 is arranged on a pipeline between the fifth gate valve 5 and the sixth gate valve 6. The sampling electrode 15 of the pH on-line monitor 14 is arranged on a pipeline 20-30 meters away from the outlet end of the deoxygenation water pump 9. The first gate valve 1 to the sixth gate valve 6 are all manual valves. The pH on-line monitor 14 is an industrial pH analyzer with various models, and in this embodiment, an HF-5310 industrial pH analyzer can be selected, but not limited to this model. The utility model discloses well dosing pump 8 is the inverter pump.
During the operation, add demineralized water, high concentration aqueous ammonia into aqueous ammonia dosing tank 7, with charge device from taking the agitator pump stirring, take out through first gate valve 1 of tank bottoms department and add the pressurization through frequency conversion dosing pump 8, add on the pipeline between the fourth gate valve 4 of deoxidization water pump 9 and deoxidization ware 10 export through second gate valve 2, the third gate valve 3 of dosing pump 8 export, add the medicament into deoxidization aquatic. A deoxygenated water sampling line is added at a position of 30 meters on an outlet pipeline of a deoxygenated water pump 9, a pH on-line monitor is installed on the sampling line, the pH on-line monitor and a variable-frequency dosing pump 8 form a composite loop, the pH value is set to be between 8.5 and 9, and after a real-time numerical value detected by the pH on-line monitor, a 4-20mA signal is sent to a frequency converter 13 to control the variable-frequency dosing pump 8, so that the aim of automatically adjusting the pH value is fulfilled.
The utility model relates to a rationally, simple structure, easy manufacturing, it utilizes industry PH on-line monitoring appearance, and the PH of in time discovering the oxygen-removed water changes, combines aqueous ammonia dosing pump automatic frequency conversion control for the aqueous ammonia charge device to add the dose, makes the pH value of oxygen-removed water stable in qualified interval, solves the pH value of oxygen-removed water feed system and corrodes the scheduling problem because of the pH value changes the pH value and causes. Meanwhile, the PH values of the feed water of each boiler drum and each steam generator are stabilized, the control of boiler water indexes is facilitated, boiler accidents caused by large fluctuation of the PH values of the boiler water, poor quality of the boiler water and the like are avoided, and the safe operation of production is guaranteed.