Non-standard equipment, as the name suggests, refers to equipment that is custom-designed and tailored to meet specific user needs, yet still manufactured in accordance with unified industry standards and specifications set by national regulations.

In the chemical industry, non-standard equipment remains quite common, including tower equipment (tower devices or stationary equipment), reactors, heat exchangers, and other such devices. These pieces of equipment can be further categorized into numerous types based on differences in function, material properties, appearance, and other factors. Below, we provide a detailed introduction to several commonly encountered non-standard devices: tower equipment, heat exchangers, reactors, and tubular heating furnaces.

Tower equipment, also known as towers or tower devices, is a piece of equipment used for mass transfer between gas and liquid phases—or between two liquid phases. It facilitates close contact between the gas (vapor) and liquid phases, enabling efficient interphase mass and heat transfer. Common unit operations that can be carried out in tower equipment include distillation, absorption, desorption, and extraction. Additionally, these devices play a crucial role in industrial processes such as cooling and recovery of gases, wet scrubbing and drying of gases, as well as humidification and dehumidification—operations that involve both gas-liquid mass transfer and heat transfer. As a result, tower equipment is among the most essential pieces of equipment in industries like chemical engineering, petrochemicals, and oil refining.

Tower equipment is broadly classified into two major categories: tray towers and packed towers. Tray towers are equipped with a specific number of trays, where gas comes into contact with the liquid layer on the trays—either through bubbling or spraying—to facilitate mass transfer. Packed towers, on the other hand, contain packing material of a certain height; as liquid flows down through the packing, gas moves countercurrently against the liquid film, enabling efficient mass transfer.

A heat exchanger is a device that transfers part of the heat from a hot fluid to a cold fluid; it is also known as a thermal exchanger. Heat exchangers play a crucial role in numerous industrial processes, including chemical, petroleum, power, food, and many other sectors. In chemical production, heat exchangers serve as heaters, coolers, condensers, evaporators, and reboilers, making them indispensable across a wide range of applications.

Its primary function is to ensure the specific temperature required for the medium throughout the process. Heat exchangers facilitate heat transfer between two or more fluids at different temperatures, enabling heat to move from the higher-temperature fluid to the lower-temperature fluid. This ensures that fluid temperatures reach the target levels specified by the process, thereby meeting the operational requirements. At the same time, heat exchangers are also one of the key pieces of equipment used to enhance energy efficiency.

According to the heat transfer method, heat exchangers can be classified into three major categories:
A direct-contact heat exchanger, also known as a mixing-type heat exchanger, is equipment that facilitates direct contact and heat transfer between hot and cold fluids. Typically, the two fluids in direct contact are a gas and a liquid with relatively low vapor pressure.

The working principle of a thermal energy storage heat exchanger relies on the heat-conducting properties of solid materials. Specifically, the hot medium first heats the solid material to a certain temperature, and then the cold medium absorbs heat from the solid material. This process enables efficient heat transfer.

The plate-type heat exchanger also utilizes the thermal conduction of a medium; in this design, the cold and hot fluids are separated by a solid wall, enabling heat transfer to occur directly through the wall. For heating companies, plate-type heat exchangers are the most widely used. Depending on their specific structure, they can further be classified into tubular heat exchangers, plate heat exchangers, and heat pipe heat exchangers.
Reactors in chemical equipment are primarily used for materials to undergo chemical reactions inside, generating new substances, or for performing unit operations such as mixing and sedimentation.

Since each unit reaction has unique characteristics, the requirements for reactors vary accordingly. Industrial reaction processes depend not only on the intrinsic properties of the reaction itself but also on the characteristics of the reactor equipment. Reactors can be classified either according to the specific features of the reaction or based on the attributes of the equipment.

Reactors can be classified into two types based on the phase state of the reactant system: homogeneous and heterogeneous. Homogeneous reactors, in turn, are further divided into gas-phase reactors and liquid-phase reactors. These reactors are characterized by the absence of a phase interface, meaning their reaction rates depend solely on temperature, concentration (and pressure). Heterogeneous reactors, on the other hand, include five distinct types: gas-solid, gas-liquid, liquid-liquid, liquid-solid, and gas-liquid-solid interactions.

Based on the characteristics of reactor structure, reactors can be classified into batch reactors, tubular reactors, packed-tower reactors, fixed-bed reactors, and fluidized-bed reactors, among others.

It can be classified into three types according to the operation method: batch, semi-continuous, and continuous.

According to temperature conditions and heat transfer methods, it can be classified into isothermal and non-isothermal types. Based on the heat transfer method, it further divides into adiabatic, external heating, and natural convection types.

A tubular heater is a process heating furnace used in oil refining, petrochemicals, chemicals, and the chemical fiber industry. It features a combustion chamber encased in refractory materials and works by utilizing the heat generated from fuel combustion to raise the temperature of materials.

Working Principle of Tubular Heaters

1. The three main parts of a tubular furnace are: the radiant chamber, the convection chamber, and the chimney.

2. Working Principle: Fuel oil is sprayed out in a misty form, mixes with air, and then burns to produce high-temperature flue gas. This gas rises from the bottom up, passing through the radiant chamber into the convection chamber where it transfers heat to the oil products, thereby reducing the gas temperature. Finally, the flue gas is discharged through the chimney.

The heating medium in a tubular heater is highly corrosive oil and gas, while the fuels used are both liquids and gases. The heating method employed is direct heating, enabling long-term, continuous operation without interruption. This type of equipment is specialized and commonly utilized in industries such as coking, metallurgy, glass manufacturing, and lithium-battery production. The emergence and widespread application of tubular heaters have significantly boosted the development of these industries.