PurposeThe furnace is used for oil emulsions heating and oil stabilization with capacity of 1500–3000 tons/day. The PPN-3 furnace is designed for small oil fields. It is the best choice by such parameters as operating efficiency, steel intensity and rate of use of fuel.
The furnace provides highly effective “soft” mode of oils heating due to equalization of average values of calorific intensity along the heating surface.
Technical Data
| Heat capacity, | MW | 3,0 |
| Product capacity | t/h | 62,5–125 |
| Product heating temperature, max: | ||
| For treatment mode | °Ñ | 90 |
| For stabilization mode | °Ñ | 250 |
| Fuel: | Natural or oil-well gas, dried and stripped, with hydro-gen sulfide concentration of max. 0,002% mass., from independent distribution point | |
| Coil operation pressure, max. | MPa | 6,3 |
| Coil pressure drop, max | MPa | 0,25 |
| Efficiency, min. |
% | 80 |
| Dimensions (length x width x height) |
ì | 7,5 × 3,7 × 8,0 |
| Mass, max. |
t | 20 |
Structural description and operation of the PPN-3 furnace
The furnace was designed based on the technical solutions providing high operation reliability, cost-effectiveness, decrease of specific metal content and dimensions.
The features mentioned are implemented in furnace design due to the principle of combustion gases recirculation using ribbed pipes system. This allows decreasing of heat stream at heat surface to 50 KW/m2 in parallel with increase of specific heating area higher than in 4 times. At that, the flare temperature decrease to 1000°Ñ and high intensive heat sink to the product heated provide heating conditions, where coil wall temperature exceeds the heating product temperature at maxi-mum of 100–120°C; this allows using the furnace for oil heating during stabilization processes.
Processing modules of the furnace are interconnected and connected with other oil treatment equipment via piping, cables, power wiring and automatic controls connections. Heat-exchange chamber is a metal thermal-insulated enclosure; product coils of ribbed pipes are arranged inside.
Heat-exchange chamber provides heat exchange between the products of fuel combustion, washing the external surfaces of coils, and the heated medium, flowing inside them.
Heat exchange chamber is equipped with two stacks with built-in utilizers for fuel gas heating. There are sight ports on side-walls of chamber body; in the front wall, there is connection for inert gas supply, or for steam supply from fire-control unit.
There are two explosion valves installed in the top wall of the chamber. Firebox is in the basement of heat-exchange cham-ber; it is located in the way where its central line coincides with vertical line of the chamber. The heat chamber is mounted on a frame structure of furnace foundation. Combustion chamber, valves and regulating elements, ventilating unit with airline and a choke are arranged inside. The equipment of furnace foundation has wind-protection fences.
Instrumentation
The furnace employs microprocessor automation system alongside with actuating devices, providing:
– set operation mode;
– monitoring of gas-air medium condition up to explosive level; product combustion monitoring in heat-exchange chamber;
– connection to automatic fire-control unit.
Automation control system is a complex of monitoring, alarm and control devices, installed in the process section of the fur-nace, and in the control room. Instrument module is a heat-insulated room where control board, power frame, heater frame and lighting system are arranged. The furnace provides heating of the oil emulsion flowing inside the coils by the way of heat supplied by combustion products.
The "soft" mode of product heating is achieved by the way of even distribution inside of heat-exchange chamber due to in-tensive recirculation of combustion products. Microprocessor control system allows keeping of the set proportion between fuel gas and air, thus providing stoichiometric combustion of fuel mixture.
