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I. Structural Introduction
The new DZH series steam boiler is a single-drum vertical water-fire tube shell boiler with traveling grate as the combustion equipment. The water walls on the left and right sides of the furnace are radiant heating surfaces, the wings of the furnace are convective heating surfaces, and the threaded flue tubes are arranged inside the drum as convective heating surfaces. The furnace wall is made by the new technology of integral casting and tamping with heat-resistant concrete, and the outer side of the boiler main unit is a three-dimensional guard plate shell.
In terms of the overall structure, the boiler main body adopts the form of an upper-mounted drum, with water wall tubes and headers arranged symmetrically left and right. The drum is formed by welding the cylinder body and the front and rear tube sheets. A spark baffle wall is arranged in the furnace of the boiler, ensuring high combustion efficiency.
This series of boilers adopts the latest scientific research achievements, such as arched tube sheets and threaded flue tubes, which solves the problems of shell boilers such as tube sheet cracks, water wall tube bursts, low thermal efficiency, insufficient output and poor coal adaptability.
II. Combustion Process
Fuel enters the furnace through the traveling grate for combustion. The generated flue gas enters the wing convection tube bundle through the outlet smoke window on the splayed wall along the bottom of the drum, enters the threaded flue tube through the front smoke box, passes through the economizer and dust collector, and is drawn by the induced draft fan to be discharged into the atmosphere through the chimney.
III. Technical Features
1. The drum is composed of arched tube sheets and threaded flue tubes, which changes the drum from a quasi-rigid body to a quasi-elastic structure, eliminates the bracing members in the tube sheet area, and reduces stress. The flue tubes in the tube sheet are changed from two passes to a single pass, solving the problem of tube sheet cracks.
2. Due to the arrangement of riser tube rows at the lower part of the drum, the dead water area at the bottom of the drum is eliminated, making it difficult for sludge to deposit. The high-temperature area of the drum can be well cooled, preventing the lower part of the drum from bulging.
3. The high-efficiency heat transfer threaded flue tubes are adopted to achieve the effect of enhanced heat transfer, realizing the characteristics of fast temperature rise and pressure rise of the boiler, and improving the thermal efficiency of the boiler.
4. Compact structure, compared with the same type of boiler, it has small overall dimensions, saving the capital investment of the boiler room.
5. Stable operation, convenient adjustment and sufficient output.
6. Threaded flue tubes are used to enhance heat transfer, improving the heat transfer coefficient and thermal efficiency. Due to the disturbance of flue gas in the tubes, it is not easy to accumulate dust in the flue tubes, playing a self-cleaning role.
7. The splayed wall and outlet smoke window in the furnace have a certain dust reduction effect, controlling the original dust emission concentration of the boiler below the standard, and ensuring that the boiler smoke and dust emission meets the indicators specified in the national environmental protection regulations.
IV. Basic Parameters
Capacity | 2—20 tons of steam |
Thermal Efficiency | 80—84% |
Applicable Fuels | Direct combustion fuels such as straw and rice husk, formed biomass and biomass mixed fuels |
Application Scope | Supply of process hot water and steam, public heating, central heating |
DZH series coal-fired steam boiler schematic diagram
DZH Type Steam Boiler
I | Model Meaning |
D | Single drum |
Z | Longitudinal arrangement |
H | Water-fire tube combined structure |
Core Structure & Working Principle
Structural Features
Boiler drum | Single drum arranged longitudinally at the upper part. |
Furnace | Water wall tubes on both sides (radiant heating surface). |
Convective heating surface | arranged threaded fire tubes inside the boiler drum for enhanced heat transfer. |
Combustion equipment: | |
DZH (hand-fired): | Movable/hand-operated grate, manual coal feeding. |
DZL (packaged) | Light chain grate, mechanical automatic coal feeding. |
Integrityactory-assembled, ready for operation after connecting pipelines and circuits on site. |
Working Process (Three Passes)、
First pass | Fuel burns on the grate, and high-temperature flue gas heats the furnace water walls. |
Second pass | Flue gas turns via the rear arch and scours the outer wall of the boiler drum and water walls. |
Third pass | Flue gas enters the threaded fire tubes inside the boiler drum for final heat exchange, then discharges through the chimney via economizer and dust collector. |
III. Main Technical Parameters (Common Specifications)
IV. Performance Characteristics
Compact structure, small footprint and low infrastructure investment.
Easy installation, short installation period and low cost with packaged delivery.
High thermal efficiency up to 80%-85% with enhanced heat transfer by threaded fire tubes.
Wide fuel adaptability for bituminous coal, anthracite, biomass pellets, firewood, etc.
Good load adaptability with large water capacity, stable steam pressure and flexible load fluctuation.
Simple operation with manual/semi-automatic control and convenient maintenance.
V. Application Scope
Widely used in industries requiring industrial steam or heating, such as textile, printing and dyeing, paper making, food, chemical industry, pharmacy, feed, concrete curing, hotels, schools, etc.
VI. Difference Between DZH and DZL
DZH | Single drum, movable grate (hand-fired/packaged), capacity generally ≤6 tons |
DZL | Double drums, chain grate (fully automatic), capacity 2-20 tons. |
