Working agent heating unit UNA-2.8-7.7 is designed for combustion of permanent, periodic, and emergency gas discharges and their disposal by means of heat recovery for heating of recycled process water using the heat of exhaust gases.
Main parts of UNA-2.8-7.7
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- combustion chamber,
- pump station,
- cylinder cabinet,
- fuel gas control unit,
- control panel,
- control cabinet.
The combustion chamber consists of the following main assemblies: housing, coil, adjustable air inlets, collectors, pilot burner.
The housing is a tube with coils and main burners installed inside. The pilot injection burner and sight tube are inserted through fittings in the housing cavity, and air inlets are mounted on the surface.
The coil is a pipeline of the required diameter and length located on the inner surface of the chamber housing, in which the water circulates forcedly.
In the lower part of the housing, air inlets are placed evenly around the circumference, which serve to regulate the air supply to the combustion area. The flaps are adjusted manually when the unit is set to the required mode. The flaps are set to the required position depending on the temperature in the combustion chamber.
The collector is a tube with the main burners installed in the upper part. Burners have multiple openings through which the combustion gas is released into the combustion zone.
Pilot injection burner (GDI) serves to ignite the discharged gas and support the burning of the main flame. The GDI consists of a housing, a spigot for the preparation of the combustible mixture, and a sealed enclosure. In addition, the GDI includes an ignition electrode and a high voltage source.
The sight tube is designed for mounting a flame control relay sensor, which is used to indicate the presence or absence of flame and signal for automation systems.
Gas cylinder unit (GBU) serves to place two propane cylinders and a heater to maintain a positive air temperature inside the structure.
The GBU is a metal cabinet with the piping, two cylinders, two gas reducers, and two ball valves installed inside. The piping is connected by flexible gas lines and is attached to the mounting plate with clamps. The heater is attached to the bottom of the mounting plate and is used to heat the air inside the cabinet and maintain a temperature of +5 °C with the built-in thermostat. Connection box is installed outside the metal cabinet. Heater and box are explosion-proof. The inner surface of the cabinet is lined with insulation. The cabinet has two metal cable glands (one reserved) to seal the heater cable outlet passage.
The fuel gas control unit is designed for manual regulation of fuel gas pressure as well as its automatic supply (cut-off) in accordance with control signals of fuel gas pressure presence (absence).
GRPSh is a metal cabinet with the piping, ball valves, pressure regulators, solenoid valves, heater, indicating and displaying pressure gauges installed inside. The connection boxes are installed outside of the metal cabinet. Valves, heater, pressure gauges, indicating alarms, and boxes are explosion-proof.
The cabinet consists of an enclosure and a hinged door. The housing and doors are made of steel sheet. The housing is load-bearing. The inside of the housing and the doors are lined with insulation.
Connection of the unit to external piping is flanged (galvanized metalware, gaskets and mating flanges are included in the cabinet).
The valves are used to supply (cut off) fuel gas.
Pressure gauges output signals of the presence (absence) of the required fuel gas pressure on the combustion mixture lines and combustible mixture (propane-butane) at the inlet and outlet to the GRPSh, respectively. The control panel is designed for local control of ignition of pilot burners. The control panel is a cabinet with the necessary set of buttons and indicators mounted on the front door.
The control cabinet consists of the housing, the necessary set of starting and protection equipment, automation equipment (PLC), and a set of indication and control elements located on the front door. The control cabinet receives signals from instrumentation devices, processes them according to a preset algorithm, and outputs control signals to actuators according to a preset algorithm.
Frequency converters are provided as part of the control cabinet to control the capacity of circulation pumps. Depending on the fluid temperature at the combustion chamber outlet, the pump capacity is increased/decreased.
The pumping station is designed to provide water circulation in the UNA. The station consists of an enclosure-box, inside which the piping, electric pumps (main, reserved, and make-up), pressure gauges, indicating alarms, vacuum pressure gauge, heater, gas analyzer, lamp, fan, check valves, mesh filter, membrane expansion tank, water make-up tank, ball valves, and ball socket valves are installed.