Hot blast

Types of hot blasts

Industrial hot blasts are complex and massive pieces of equipment. Nonetheless, they can be categorized into a few types based on certain parameters, as follows:

• Type

  This classification focuses on the construction and working principles of hot blast furnaces.

  Classic Hot Blast Stove: The classic hot blast stoves utilize retorts to heat the air forcibly bound for the blast furnaces. Normally, the stoves operate by alternating the stoves supplied to the blast furnaces. So, these stoves would be heated in the first place, and then the previously heated ones would give off the hot air. The pace of such a cycle could be lengthy and take several hours. This stove design was first implemented in the second half of the 19th century.

  Checker Hot Blast Stove: The checker hot blast stoves are quite similar to the classic ones; however, they are equipped with checker chambers. These chambers are constructed with brick checkers, which serve the purpose of storing and re-emitting heat more rapidly when compared to the classic furnace. Therefore, the alternate operations of the stoves are no longer mandatory, and the stove can serve the furnaces continuously. Thus, the hot blast would be more efficient, and the stoves would use less fuel.

  Counter-Current Hot Blast Stove: With a similar working principle, the counter-current hot blast stoves gasify fuels first and then let out the hot air from the opposite direction to where the fuel is being injected. Thus, the fuels and the gasification processes are in parallel with the air flow, which enhances the heat exchange and boosts the thermal efficiency.

• Use

  Blast hot air furnaces are used in foundries and ironmaking industries. In these specific industries, the food source is coke or other carbon sources. Therefore, coke hot blast stoves are used to ensure that the iron ore can be processed and smelted into iron efficiently, and at the same time, the byproduct of the processing can be utilized by blast furnaces.

Specification and maintenance of hot blast

The specifications of hot blast stoves vary depending upon the application of the industry, type of the stove, and the demand of the industry blast furnace. The height of the stove can be as much as 15-50m. The diameter ranges from 8-12m. The stoves have the capacity to hold somewhere between 40,000-80,000 cubic meters of air.

The temperature of the hot air produced by these stoves ranges anywhere between 1100-1250 degrees Celsius. The stoves have the capacity to produce 45,000-70,000 cubic meters of hot air in one hour. The pressure of the hot blast air can range anywhere between 0.2-0.4 MPa.

The longevity of a hot air blast stove depends upon the material used in the manufacture of the stove. The outer part of the stove is commonly made up of iron and may last for around 20 years. The inner lining is made of refractory brick or steel fiber and can last for about 10-15 years. If the stoves are properly maintained and taken care of, they can last for a very long period of time, and the productivity will not be affected.

It is really important to maintain the hot blast furnace of the industry to get the optimal output. If the furnaces are not taken care of, they can become a liability, and the operating costs of the industry will increase. The following maintenance tips can help industries get the best use out of their blast stoves:

• Regular inspection: It is very important to regularly check how the hot blast stove is working. Any abnormalities or irregularities in the functioning of the stove should be looked at immediately. Regular inspections can help the industry avoid any major breakdowns or accidents that can affect the production line.
• Condition Monitoring: The vital parts of the hot blast stove, such as the burner, refractory lining, insulation, etc., should be monitored carefully. Any signs of wear and tear or damage should be looked at immediately and repaired without any delay. Routine monitoring of such important parts can ensure that the hot blast stove works efficiently and its longevity is preserved.
• Repair and Maintenance: If any signs of damage or wear and tear are shown, they should be repaired on an immediate basis. Any small damage, if not looked at immediately, can become a big issue and affect the working of the entire hot blast stove.
• Cleanliness: It is very important to keep the hot blast furnace or stove clean and tidy. Any build-up of residue, pollutants, or dirt can affect the working of the stove and decrease its efficiency. Keeping it clean and getting rid of any unnecessary build-up can allow the hot blast stove to breathe and operate freely.

Scenarios of hot blasts

Industry(industries) where hot blast stoves are commonly used:

• Iron and Steel industry

  Hot airflow is a fundamental element in the iron and steel industry. Hot-blast stoves are designed and utilized extensively. In the iron and steel smelting process, a large quantity of hot air is needed to ensure that the furnace operates efficiently and produces high-quality iron and steel.

• Manufacturing industry

  The manufacturing industry includes a wide range of sectors such as automotive, machinery, electrical appliances, construction materials, shipbuilding, etc. The entire industry requires hot air to dry, cure, and heat-treat products and materials to improve product quality and production efficiency.

• Chemical industry

  In the chemical industry, the demand for blast hot air is also quite substantial. Many chemical production processes need to rely on hot air to carry out reactions, drying, distillation, and other operations. For example, the petrochemical industry needs to process and refine petroleum and natural gas; the specialty chemical industry needs to produce chemical products such as pesticides, fertilizers, and pigments, etc.

• Ceramic industry

  In the ceramic industry, hot air plays an important role in the firing and drying of ceramic products. Products such as porcelain stoneware, pottery, porcelain tiles, etc. need to be produced through high-temperature roasting and drying processes to ensure that they meet the quality requirements. The hot air blast stove may provide a constant source of heat for this procedure.

• Cement industry

  As one of the important building materials, cement production requires a large amount of energy. The hot air blast stove provides the required heat for cement production by burning fuel to increase the heat and maintain the temperature, including the raw material drying, calcination, and clinker cooling processes.

• Glass industry

  In the glass industry, products such as flat glass, container glass, and optical glass, etc. need to be produced through high-temperature melting and annealing processes. The blast hot air stove may provide a constant source of heat for these high-temperature processes, thereby ensuring the stability and quality of glass products.

• Non-ferrous metallurgy

  The hot blast stove also plays an important role in non-ferrous metallurgy such as copper, aluminum, zinc, lead, tin, etc. It provides the required heat for smelting, refining, and other processes by burning fuel to increase the blast temperature and maintain the blast volume.

How to Choose Hot Blasts

• Demand analysis:

  In the first step, business buyers should analyze the needs of their target customers. Demand analysis includes factors like the size of target customers, the application scenario, and the customer's requirements for performance and function. By understanding the needs of target customers, business buyers can select models that meet customer requirements to ensure market competitiveness.

• Technical parameters:

  Next, business buyers need to consider the technical parameters of hot blast stoves, including power, heating capacity, temperature control range, and fuel type. Buyers should choose hot blast stoves with appropriate technical parameters according to business scale and application fields to ensure performance and efficiency.

• Quality and reliability:

  Quality and reliability are crucial factors in the purchasing decision. Buyers should choose reputable brands and well-manufactured products. They can refer to product reviews and brand reputation to ensure product quality and reliability.

• Cost performance:

  Buyers need to comprehensively evaluate the cost performance of hot blast stoves. They should compare the price, performance, quality, and other aspects of different products and choose those with reasonable prices and excellent performance to ensure investment value.

• Supply chain and service:

  When making purchases, buyers also need to consider the supplier's supply chain and service system. They should choose suppliers with stable supply capabilities and reliable after-sales service to ensure timely equipment maintenance and support.

Hot blast FAQ

Q1: How does a hot blast stove work?

A1: In a hot blast stove, hot air is produced by burning blast furnace gas or any other fuel in a stack lined with refractory bricks. The air is then transported to the blast furnace to improve the extraction and processing of iron ore.

Q2: Why is hot blast used in the furnace?

A2: The use of hot blast in blast furnaces improves the production of iron by approximately twenty-five percent, decreasing the quantity of coke required by fifty percent and increasing the furnace's efficiency.

Q3: What is the difference between hot blast and cold blast?

A3: The cold-blast process uses natural air, which results in low-quality cast iron with a higher coke consumption and lower blast furnace efficiency. On the other hand, the hot-blast stoves transform natural air into heated air by utilizing hot blast stoves, which leads to higher cast iron production, more efficient use of fuel, and the blast furnaces operating under a highertemperature.

Q4: What is the hot blast of a furnace?

A4: The hot blast of a furnace is an industrial stove that generates hot air from the combustion of fuel or gas. It is mainly used to ensure the consistent supply of hot air necessary for the chemical reactions and processes that occur in blast furnaces during the extraction of iron from iron ore.