Understanding Medium Pressure Boilers

Part 1: Introduction to Medium Pressure Boilers

A medium pressure boiler is a vital equipment in various industrial applications where efficient steam generation is needed. Specifically, it operates in the range of 3.8 MPa to 5.3 MPa, placing it between low-pressure and high-pressure boilers.

Differences Between Low, Medium, and High-Pressure Boilers

The primary difference between these types of boilers lies in their operating pressure. Low-pressure boilers operate below 3.8 MPa, making them suitable for applications like heating systems and low-temperature processes. In contrast, high-pressure boilers operate 9.8MPa≤P＜13.7MPa, often used in power generation and large industrial settings.

Medium pressure boilers, as the name suggests, occupy this intermediate space. They provide a balance of efficiency and safety, making them ideal for industries requiring moderate steam output. Typical applications for medium pressure boilers include:

• Food Processing: Where steam is needed for cooking, drying, and sterilization.
• Textiles: Where steam is essential for dyeing and finishing processes.
• Chemical Manufacturing: For reactions and distillations that require consistent temperature and pressure.
• Pharmaceuticals: For sterilization and heating of various processes.
• Paper Mills: Where steam is utilized throughout the manufacturing process.

The versatility and capacity of medium pressure boilers make them a preferred choice in these industries.

Part 2: ZOZEN’s Medium Pressure Boilers
Among the manufacturers providing medium pressure boiler solutions, ZOZEN stands out with its ZZ series of medium temperature and medium pressure oil/gas steam boilers. These boilers are engineered to meet the needs of various applications while ensuring energy efficiency and reliability. Capacity: 20 – 130 t/h, working pressure:2.5 – 5.4 MPa, Thermal efficiency ≥98%. ZOZEN’S Medium Pressure Boilers are classified as three types below.

1. ZZ Series Single-drum Boiler
   

   ZOZEN ZZ Series Single-drum Boiler

   Features:Adhering to the energy conservation and environmental protection concept, ZOZEN Boiler has innovatively developed the “O” type medium-pressure oil/gas-fired steam boiler, which has obtained a national utility model patent (Patent No.: CN202021759997.6). The boiler adopts a full-combustion technology and features a horizontal water-tube layout in the furnace, presenting an “O” shape, hence the name “O” type boiler. The rear flue of the boiler is horizontally arranged, with a high-temperature superheater, a low-temperature superheater, and a high-temperature economizer installed inside it. A low-temperature economizer and an air preheater are arranged behind the rear flue. Alternatively, only a low-temperature economizer and a condenser can be installed in the rear flue without an air preheater, depending on actual needs. The flue gas flows out from the air preheater or condenser and is discharged into the atmosphere through the chimney.

   2. ZZ Series Double-drum Boiler

   

   ZOZEN ZZ Series Double-drum Boiler

   Features: This medium-temperature and medium-pressure oil/gas-fired boiler features a double-drum, vertical, D-type layout. The right side houses the furnace, while the left side contains the convection bank. The superheater is typically installed within the convection bank. The boiler is fixed to the base frame via movable supports at the middle and both ends of the lower drum, allowing for free thermal expansion towards both ends.The furnace is surrounded by membrane water walls. The membrane water wall on the left side of the furnace completely separates it from the convection bank. The rear part of the convection bank has a staggered tube arrangement, while the front part has an in-line arrangement, with a horizontal serpentine superheater installed in the middle.Flue gas generated by combustion in the furnace exits from the bottom of the furnace, passing through the combustion chamber, convection bank, and superheater tubes. It then turns left and flows through the spiral finned tube economizer and condenser before entering the flue duct and being discharged to the atmosphere via the chimney.

   3.ZZ Series Corner Tube Boiler

   

   ZOZEN ZZ Series Corner Tube Boiler

   Features:The corner-tube gas-fired boiler uses a piping system as the framework for the entire boiler. Since this framework bears all the loads of the boiler’s heating surfaces on its own, it is also known as a frame-free boiler. Meanwhile, this framework also serves as the boiler’s downcomers and upper and lower headers.
   The boiler features an external drum, a fully enclosed membrane wall furnace, and a flag-type tube structure for the convection heating surfaces. The corner-tube boiler offers advantages such as a compact structure, low steel consumption, and rapid temperature rise, which have led to its wide application. This boiler is of a knock-down structure.

   Advantages of ZOZEN’s Medium Pressure Boilers

• High Efficiency: ZOZEN’s medium pressure boiler series operates at a high efficiency rate, often exceeding 98%. This efficiency translates into reduced fuel consumption and lower operating costs.
• Advanced Technology: The ZZ series incorporates cutting-edge technology, such as automated control systems that enhance operational performance while ensuring safety.
• Customizable Options: ZOZEN offers a range of configurations to suit specific client requirements, including different fuel types and output capacities.
• Robust Construction: Constructed using high-quality materials, the medium pressure boilers from ZOZEN are designed to withstand rigorous operational demands.
• Eco-Friendly Design: The boilers are built to minimize emissions, complying with environmental regulations and promoting sustainable practices.

Industry Applications

ZOZEN’s medium pressure boiler is perfect for industries that benefit from steam generation. Whether it’s for heating, power generation, or process applications, ZOZEN’s solutions are tailored to meet diverse demands.

Case introduction: Heilongjiang Changfeng Coking Co., Ltd., founded in 2014, is mainly engaged in the production of coke, tar, crude benzene and other chemical products. In the second half of 2019, the company invested over 60 million RMB to launch a 6 MW coal gas thermal power project, supporting a 45 tph gas-fired boiler and a 6 MW condensing steam turbine generator set. As a key municipal-level industrial project highly valued by the local government, the project is designed to generate an annual output of 60 million kWh of electricity and build a heating network covering 300,000 square meters upon completion. The supporting steam boiler features a rated pressure of 3.82 MPa and a steam temperature of 450℃, classified as a Class A medium-temperature and medium-pressure boiler, imposing extremely strict demands on boiler design and manufacturing.

After in-depth research and comprehensive demonstration targeting the coking and chemical industry’s gas utilization and high-standard steam demands, ZOZEN technical team customized a ZZ series medium-temperature and medium-pressure gas-fired superheated steam boiler for Changfeng Coking, a leading solution in the domestic market. Adopting an O-type structure, the boiler delivers a compact layout, sufficient furnace flame fullness, convenient on-site installation and reduced main equipment investment.
Backed by a strong R&D and design capability, ZOZEN conquered multiple technical challenges in the design of medium-temperature and medium-pressure gas-fired boilers, effectively enhancing operational safety. In particular, unreasonable superheater structure often leads to critical hazards such as insufficient superheat temperature, overheating and even tube bursting, all of which were thoroughly resolved through ZOZEN’s optimized design.

The project also demonstrates ZOZEN’s advanced manufacturing strength. The boiler drum, with a thickness of up to 60 mm, is processed by high-precision CNC plate rolling machines and drum drilling machines, guaranteeing operational efficiency, improving surface finish and minimizing dimensional deviations. At present, the Changfeng Coking project has been successfully commissioned, with the boiler running safely, stably and efficiently for the coking and chemical production system.

Part 3: ZOZEN’s Strengths and Service System

ZOZEN is recognized not only for its high-quality medium pressure boilers but also for its exceptional service and support system.

• Expertise and Experience
  With years of experience in the boiler manufacturing industry, ZOZEN has developed extensive expertise in providing suitable steam solutions. Their engineers work closely with clients to identify the optimal medium pressure boiler configuration for specific applications.
• Comprehensive Support
  The company offers a complete range of services, from consultation and design to installation and after-sales support. ZOZEN provides training for operational staff, ensuring that users are well-equipped to manage the medium pressure boiler effectively.
• Quality Assurance
  Quality is at the forefront of ZOZEN’s manufacturing process. Each medium pressure boiler undergoes rigorous testing to ensure it meets international standards. The company is committed to continuous improvement, regularly updating its technologies and practices to better serve clients.
• Customer-Centric Approach
  ZOZEN prioritizes customer satisfaction. They maintain open communication lines with clients, allowing for quick responses to inquiries and concerns. Their focus on building long-term relationships has earned them a loyal customer base.

Conclusion

Medium pressure boilers play a crucial role in various industries, bridging the gap between low and high-pressure systems. ZOZEN’s medium pressure boiler solutions, particularly the ZZ series, embody efficiency, reliability, and advanced technology. With an unwavering commitment to quality and customer service, ZOZEN stands out in the boiler industry, making them a trusted partner for businesses requiring robust steam generation solutions. The capability of medium pressure boilers to cater to diverse industrial needs makes them an indispensable asset in modern manufacturing processes.

In summary, the medium pressure boiler is not just a piece of equipment; it is a cornerstone for efficiency and productivity in many sectors.