Boiler dosing device

Overview: Boiler dosing device is a new concept of chemical water treatment dosing technology, which has been widely used in power plants and power stations at home and abroad. It is a complete unit combination that installs all equipment and components such as metering pumps, dissolving tanks, control systems, and pipeline valves on the same base platform, achieving functions such as solution preparation, stirring, and metering.
The unit combination form of the boiler dosing device mainly depends on the capacity of the unit, the configuration of the boiler (two boilers share one set, three boilers share one set, or single boiler single set, etc.), the degree of automation control (automatic or manual control), and the selection of the type of dosing pump (metering pump) (diaphragm metering pump or plunger metering pump). It can be flexibly composed into various forms of units and installed on a base. This industrialized whole set device greatly reduces the workload of design and on-site installation, providing reliable guarantees for the quality, safety, and on-site operation of the whole machine
The materials of each component of the boiler dosing device are mainly divided into several forms, such as stainless steel, carbon steel (carbon steel lining rubber), non-metallic materials (PE, PVC, PP, PTFE), etc., depending on the needs of the user.
Our company relies on years of accumulated technology and experience in water treatment, and according to the treatment requirements and dosing characteristics of different water qualities, we draw on and absorb advanced dosing technologies at home and abroad to provide high standard water treatment system design ideas and solutions. We have developed and launched a new combination dosing device with reliable performance, flexible configuration, and the ability to meet users' arbitrary choices.
Main categories:
The boiler dosing device can be divided into: hydrazine deoxygenation dosing device, pH adjustment ammonia dosing device, phosphate dosing device, and ferrous sulfate coating dosing device according to different usage situations.

Phosphate dosing device

Process principle:
The hardness of calcium and magnesium in boiler feedwater can undergo chemical reactions or concentrate and crystallize at high temperatures, forming insoluble scale that firmly adheres to the heating surface of the boiler. This scale is a poor conductor of heat and can hinder heat conduction. In severe cases, it may lead to boiler tube bursting accidents. In addition, it can also induce and exacerbate chemical corrosion of metals under the scale, which is quite harmful.
Although the boiler condensate and feedwater have undergone strict softening and desalination treatment, there is still a small amount of calcium and magnesium hard water entering the boiler water. If this hard water is not treated, scaling will also pose a threat to the safe operation of the boiler. Currently, adding phosphate to the boiler water is a suitable treatment method, and the reaction is as follows:

Alkaline calcium phosphate is a soft water residue that is easily discharged with boiler discharge and will not adhere to the boiler to form scale.
Process Overview
This device mainly includes four parts: drug solution preparation system, metering and dosing system, safety system, and control system.
Solid phosphate is added to the dissolution tank, and then mixed with desalinated water or condensed water in proportion to dissolve. It is then added to the boiler steam drum through a metering system. The dosing control can be done manually or automatically based on the control signal output by the upper system.
Scope of application:
High pressure and higher parameter steam drum boiler water treatment

Ammonia addition device (adjusting pH value)

Process principle:
The free CO2 in water can make it acidic, and the reaction is as follows:

In this way, H+in water can cause hydrogen depolarization corrosion of metals such as carbon steel, resulting in damage to iron components. The reaction is as follows:

Especially in high-temperature and non buffering chemical desalinated water, free CO2 can greatly promote steel corrosion, so it is necessary to suppress this electrochemical reaction.
Adding ammonia to water to increase its pH value can effectively inhibit the dissociation of H+and control metal corrosion.
Process Overview
This device mainly includes five parts: liquid medicine metering system, dissolution system, metering and dosing system, safety system, and control system.
Ammonia water is drawn into the metering system through a water injector, and then added to the dissolution system in proportion to mix evenly with desalinated water or condensate water. It is then added to the boiler condensate water or feedwater through the metering system. The dosing control can be done manually or automatically based on the control signal output by the upper system.
Scope of application:
Boiler condensate and feedwater treatment with medium pressure and above parameters

Amine deoxygenation and dosing device

principle
Oxygen can undergo electrochemical corrosion with metals such as carbon steel in humid environments, causing damage to iron components. The reaction is as follows:

Especially in high-temperature water supply systems, this corrosion is prone to occur and is quite severe, so dissolved oxygen in the water must be removed.
Hydrazine deoxygenation is a commonly used chemical deoxygenation method for high parameter boiler units. It exhibits strong reducibility in alkaline aqueous solutions and can reduce dissolved oxygen in water. The reaction is as follows:

Process Overview
This device mainly includes five parts: liquid medicine metering system, dissolution system, metering and dosing system, safety system, and control system.
Hydrazine is drawn into the metering system through a water injector, and then added to the dissolution system in proportion to mix evenly with desalinated water or condensed water. It is then added to the boiler feedwater through the metering system. The dosing control can be done manually or automatically based on the control signal output by the upper system.
This device can not only add hydrazine, but with slight modifications, it can also add other oxygen scavengers such as carbazide and dimethyl ketoxime.
Scope of application:
High pressure and higher parameter boiler feedwater treatment

Ferrous sulfate coating dosing device

principle
The condenser is the main equipment for cooling and condensing the exhaust steam after doing work in the boiler turbine system. Once the copper tube of the condenser corrodes and leaks, the cooling water will contaminate the boiler feedwater, increase the workload of the condensate treatment device, and cause boiler scaling and corrosion. Ferrous sulfate coating is one of the commonly used corrosion inhibition methods for condensers. The addition of ferrous sulfate will form a protective film containing iron compounds on the inner wall of the copper tube, thereby preventing corrosion of the copper tube by cooling water.
Process Overview: This device mainly includes three parts: the drug solution preparation system, the metering and dosing system, and the control system.
Solid drugs are added to the dissolving tank, and then mixed with industrial water in proportion to dissolve. They are added to the circulating cooling water inlet of the condenser through a metering system. The addition control is generally manual. During membrane formation, the circulation time is about 96 hours. During membrane formation during operation, the drug is added continuously every 24 hours for 1 hour or every 12 hours for 0.5 hours.

Scope of application: Cooling circulation systems for thermal power generation or petrochemical industry.