The Action of Superheated Steam

The viscosity of heavy oil is very sensitive to temperature. As long as the temperature rises by 8~9℃, the viscosity will decrease by 1 times. If high pressure superheated steam is injected into the reservoir for thermal recovery, not only the single well production can be greatly increased, but also the recovery can reach 50%~70%.The key to improve oil recovery is to improve the quality of steam injected into the reservoir. The higher the dryness of the steam, the greater the heat carried by the steam per unit weight, the higher the effective heat injected into the reservoir and the higher the production and recovery. According to relevant data, after superheated steam huff and puff technology is used in heavy oil recovery, the output can be increased by 3~8 times and the recovery can be improved significantly. Therefore, superheated steam injection is an effective way to increase the yield of heavy oil.

How the Superheated Oilfield Steam Boiler works

The radiation heat exchange section, convection heat exchange section and water-water heat exchanger in the front stage of superheated steam injection boiler are basically the same as the normal one in structure. 70-80% wet steam is produced in the front stage during heat exchange. Then, about 99% of the dry steam is separated by the high-efficiency steam-water separator (14) and fed to the superheated section for heating, which further increases the steam temperature to become superheated steam (460 ~500℃). The superheated steam is then mixed with the unsaturated brine separated from the steam-water separator. After mixing, the temperature drops to about 370 C and the steam dryness is more than 90%. Finally, high-dry steam is injected into the well.

Main process introduction-superheated steam injection boiler

Basic structure -superheated steam injection boiler

1-Inlet pipe

2-High-pressure pump

3-Control cabinet

4-Power cabinet

5-Fan 6-Burner

7/8-Hot air duct

9-Chimney

10-Air preheater

11-Convection heat exchange section

12-Overheating section

13-Main steam valve

14-Steam-water separator

15-Ladder

16-Transition

17-Radiation section outlet pipe

18-Radiation section

Its main advantage is that the steam process from 80% to more than 90% occurs outside the boiler body. It effectively avoids the danger of tube burst due to uneven salt precipitation in heat exchanger tubes in furnace caused by high heat flow density of flame radiation/flue gas convection heat exchange.

Superheated Oilfield Steam Boiler Special Component

1.Convection Section & Overheating Section

1). The convection section in the upper part realizes the heat transfer from low temperature water to high temperature water.
2). The lower high temperature convection section realizes the convection heat transfer process from saturated steam to superheated steam. Because the heat flux density here is lower than that in the radiation section, coupled with the scouring effect of high velocity of superheated steam, a small amount of saturated water will not cause internal salt precipitation and scaling.
3). The convective heat transfer area is increased, and the exhaust gas temperature is effectively reduced to meet the national energy conservation and environmental protection requirements.
4). The control technology of dryness and oxygen content in flue gas is applied to ensure the stable and balanced operation of thermal efficiency, so that the steam injection boiler is always in the state of high thermal efficiency, so as to achieve the purpose of energy saving and efficiency increasing.
2.Steam-water Separator

The steam-water separator is a spherical or vertical vessel with built-in high-efficiency separator. A defoaming separator is set at the steam outlet to further separate small water droplets in the steam. The figure shows a newly produced 15t/h steam-water separator. Four-stage steam-water separator is used internally, which makes the separation efficiency up to 99% and meets the steam quality requirements of the superheater.
Steam-water mixer utilizes the differential pressure flow suction effect between superheated steam and separated unsaturated brine to spray separated brine into superheated steam in a foggy manner and mix it with superheated steam, thus reducing the temperature of superheated steam and keeping the final steam in an overheated state.
3. Burners

Oil and Gas Burners.
Model: KRBY1040
Brand: UNIGAS
Origin: Italy
Output power: 2550-13000kW
Atomization mode: air/steam atomization
The burner’s fan is highly integrated with the combustion system, providing programmed ignition, purge, flame monitoring and flame-out protection to adjust fuel consumption as load changes.
4. High Pressure Plunger Pump

Use high pressure five cylinder plunger pump
Model: 5GP125-15/21
Brand: Ningbo Heli
Output power: 132 kW
Use media: purified produce-water
Operating temperature: 60-80℃
Output pressure: 21MPa
5. Electronically Controlled Level Regulation Valve

Model Number:         DMC65 B1-16

Brand:                 DREHMO

Origin:                 Germany

Valve body nominal path: DN32

Valve body origin:       Dalian Zhongyi

Superheated Oilfield Steam Boiler Parameter

Rated evaporation:           23t/h

Fuel:                       Crude oil/Natural gas

Rated working pressure:      17.2MPa

Boiler thermal efficiency:      ≥91% (fuel oil)/≥92% (fuel gas)

Rated working temperature:   360℃

Operating steam superheat:   ≥5℃

Operating exhaust temperature: 160℃ (fuel oil)/130℃ (fuel gas)

Control method:              PLC + touch screen + industrial computer

Loading method:             Skid/Vehicle

Superheated Oilfield Steam Boiler Features

1. The structure and control are more complicated than ordinary boilers, and itsone-time investment is higher;
2. The enthalpy value of superheated steam is high, the steam injection efficiency is higher, the oil production volume in the steam huff and puff period is 1.2 times that of ordinary boilers, and the oil-steam ratio is 2.3 times that of ordinary boilers;
3. The mixing/overheating process is carried out in the non-heated section outside the boiler, and the safety is guaranteed.
4. The water quality requirements are equivalent to subcritical boilers, lower than supercritical boilers;