Protection process for plunger pump of oil field steam-injection boiler

Abstract

The invention belongs to the technical field of oil field steam-injection boilers, and particularly relates to an oil field steam-injection boiler plunger pump protection technology which comprises the technological processes that high-temperature reuse purified sewage is cooled; air is conveyed to an air cooler through an air blower, the high-temperature recycled purified sewage exchanges heat with the air in the air cooler, and hot air enters a hearth to assist fuel combustion; the high-temperature recycled and purified sewage enters a plunger pump after being cooled; the cooled recycled purified sewage is conveyed to a boiler water-water heat exchanger through a plunger pump; recycled and purified sewage enters a boiler convection heating surface and a boiler radiation heating surface after being subjected to temperature adjustment in the boiler water-water heat exchanger, absorbs heat to become qualified steam, and then is conveyed to an oil field steam injection pipe network. According to the invention, the temperature of water entering the plunger pump of the boiler is reduced, the failure rate of the plunger pump is reduced, and the problem of frequent start and stop of the boiler caused by high-temperature recycled sewage is solved; the temperature of water entering the water treatment system is reduced, and the service life of the boiler water treatment system is prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of oilfield steam injection boilers, and in particular relates to a protection process for a plunger pump of an oilfield steam injection boiler. Background Art

[0002] Oilfield steam injection boilers are important equipment in heavy oil development, used to inject high-temperature steam into underground heavy oil reservoirs, heat the underground heavy oil, reduce the viscosity of the heavy oil, and improve the fluidity of the heavy oil. At present, the feed water of oilfield steam injection boilers is mostly recycled and purified sewage generated during the heavy oil exploitation process. With the development of heavy oil exploitation technology, the temperature of the recycled and purified sewage has increased year by year, rising from the initial 20°C - 30°C to 70°C - 90°C, and will gradually increase in the future. The increase in the temperature of the recycled and purified sewage of oilfield steam injection boilers brings two problems to the oilfield steam injection boilers:

[0003] The existing temperature resistance of the plunger pump of oilfield steam injection boilers cannot adapt to the existing working conditions, and the failure rate of the plunger pump is high, resulting in frequent start-stop of the boiler. Therefore, the problem of plunger pump cooling caused by high-temperature recycled and purified sewage has become an urgent problem to ensure the normal production of oilfields.

[0004] The increase in the temperature of the recycled sewage of oilfield steam injection boilers leads to a decrease in the adjustment ability of the water-water heat exchanger of the oilfield steam injection boiler, an increase in the water temperature entering the convective heating surface of the boiler, an increase in the boiler flue gas temperature, and a decrease in the boiler thermal efficiency. Summary of the Invention

[0005] The purpose of the present invention is to provide a protection process for a plunger pump of an oilfield steam injection boiler, which not only reduces the temperature of the recycled and purified sewage entering the plunger pump of the boiler, but also solves the problem of frequent start-stop of the boiler caused by high-temperature recycled sewage; on the other hand, it improves the thermal efficiency of the oilfield steam injection boiler, reduces the energy consumption and carbon emissions of the oilfield steam injection boiler.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] The protection process for the plunger pump of the oilfield steam injection boiler of the present invention is characterized by including the following hardware equipment: a water treatment system, an air cooler, a plunger pump, a boiler radiant heating surface, a boiler convective heating surface, a boiler water-water heat exchanger, a blower, and a furnace;

[0008] The technological process of the protection process is as follows:

[0009] (1) Cooling treatment of the high-temperature recycled and purified sewage in the air cooler;

[0010] (2) Air is transported to the air cooler by the blower, and the high-temperature recycled and purified sewage exchanges heat with the air in the air cooler, and the hot air enters the furnace to assist fuel combustion;

[0011] (3) The high-temperature recycled and purified sewage enters the plunger pump after cooling;

[0012] (4) The recycled and purified sewage after temperature reduction is transported to the boiler water-water heat exchanger by a plunger pump;

[0013] (5) The recycled and purified sewage enters the convective heating surface and the radiant heating surface of the boiler after adjusting the temperature in the boiler water-water heat exchanger. After absorbing heat in the convective heating surface and the radiant heating surface of the boiler, the recycled and purified sewage becomes qualified steam and is then transported to the oilfield steam injection pipeline network.

[0014] During the process of cooling the high-temperature recycled and purified sewage in step (1), the high-temperature recycled and purified sewage enters the air cooler after being treated by the water treatment system, or the high-temperature recycled sewage enters the water treatment system after being cooled by the air cooler.

[0015] The air cooler is a tubular air cooler or a heat pipe air cooler.

[0016] The tubular air cooler adopts a horizontal or vertical structure. The recycled and purified sewage flows inside the pipe, and the air flows outside the pipe. The recycled and purified sewage and the air adopt a single-pass or multi-pass structure.

[0017] The heat pipe air cooler adopts a horizontal or vertical structure. The recycled sewage flows inside the pipe, and the air flows outside the pipe.

[0018] The heat exchange tube bundle of the tubular air cooler or the heat pipe air cooler adopts a structure of smooth tube, finned tube, fin tube, or stud tube.

[0019] Advantages of the present invention:

[0020] (1) The plunger pump protection process for the oilfield steam injection boiler of the present invention reduces the water temperature entering the boiler plunger pump, reduces the failure rate of the plunger pump, and solves the problem of frequent start-stop of the boiler caused by high-temperature recycled sewage;

[0021] (2) The plunger pump protection process for the oilfield steam injection boiler of the present invention reduces the water temperature entering the water treatment system and improves the service life of the boiler water treatment system;

[0022] (3) The plunger pump protection process for the oilfield steam injection boiler of the present invention does not change the existing technological process of the oilfield steam injection boiler. Only an air cooler is added. The technological process is simple, the construction volume of boiler transformation is small, and the transformation cost is low;

[0023] (4) The plunger pump protection process for the oilfield steam injection boiler of the present invention improves the regulation ability of the water-water heat exchanger, reduces the temperature entering the convective heating surface of the boiler, and improves the boiler thermal efficiency;

[0024] (5) The plunger pump protection process for the oilfield steam injection boiler of the present invention increases the air temperature entering the furnace, reduces the boiler fuel consumption, and improves the boiler thermal efficiency;

[0025] (6) The protection process of the plunger pump for oilfield steam injection boilers of the present invention improves the thermal efficiency of the oilfield steam injection boilers, reduces the fuel consumption of the boilers and the greenhouse gas emissions of the boilers at the same time;

[0026] (7) The protection process of the plunger pump for oilfield steam injection boilers of the present invention provides an air cooler for heat exchange between air and high-temperature recycled purified sewage, which has a simple structure and low manufacturing cost;

[0027] (8) The protection process of the plunger pump for oilfield steam injection boilers of the present invention provides that the heat exchange tube bundle of the air cooler adopts structures such as smooth tubes, fin tubes, finned tubes, stud tubes, etc., which enhances the heat transfer capacity of the heat exchange tube bundle, makes the air cooler structure compact, and reduces the floor area of the air cooler. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is the process flow of the present invention Figure Ⅰ .

[0029] Figure 2 is the process flow of the present invention Figure Ⅱ .

[0030] Figure 3 is the schematic structural diagram of the tubular air cooler of the present invention.

[0031] Figure 4 is the schematic diagram of the fluid flow of the air cooler of the present invention.

[0032] Figure 5 is the schematic structural diagram of the heat pipe type air cooler of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0033] The following further describes the specific embodiments of the present invention with reference to the drawings.

[0034] The protection process of the plunger pump for oilfield steam injection boilers of the present invention is characterized by including the following hardware devices: a water treatment system 1, an air cooler 2, a plunger pump 3, a boiler radiant heating surface 4, a boiler convection heating surface 5, a boiler water-water heat exchanger 6, a blower 7 and a furnace 8;

[0035] The process flow of the protection process is as follows:

[0036] (1), Cooling the high-temperature recycled purified sewage in the air cooler 2;

[0037] (2), The air is transported to the air cooler 2 by the blower 7, and the high-temperature recycled purified sewage exchanges heat with the air in the air cooler 2, and the hot air enters the furnace 8 to assist fuel combustion;

[0038] (3), The high-temperature recycled purified sewage enters the plunger pump 3 after cooling;

[0039] (4) The recycled and purified sewage after temperature reduction is transported to the boiler water-water heat exchanger 6 by the plunger pump 3;

[0040] (5) The recycled and purified sewage enters the boiler convection heating surface 5 and the boiler radiation heating surface 4 after adjusting the temperature in the boiler water-water heat exchanger 6. After absorbing heat in the boiler convection heating surface 5 and the boiler radiation heating surface 4, the recycled and purified sewage becomes qualified steam and is then transported to the oilfield steam injection pipe network 9.

[0041] In the process of cooling the high-temperature recycled and purified sewage in step (1), the high-temperature recycled and purified sewage enters the air cooler 2 after being treated by the water treatment system 1, or the high-temperature recycled sewage enters the water treatment system 1 after being cooled by the air cooler 2.

[0042] The air cooler 2 is a tubular air cooler or a heat pipe air cooler.

[0043] The tubular air cooler adopts a horizontal or vertical structure. The recycled and purified sewage flows inside the pipe, and the air flows outside the pipe. The recycled and purified sewage and the air adopt a single-pass or multi-pass structure.

[0044] The heat pipe air cooler adopts a horizontal or vertical structure. The recycled sewage flows inside the pipe, and the air flows outside the pipe.

[0045] The heat exchange tube bundle 10 of the tubular air cooler or the heat pipe air cooler adopts a structure of plain tube, fin tube, finned tube, or stud tube.

[0046] An oilfield steam injection boiler plunger pump protection process described in the present invention is composed of a water treatment system 1, an air cooler 2, a plunger pump 3, a boiler radiation heating surface 4, a boiler convection heating surface 5, a boiler water-water heat exchanger 6, a blower 7, a furnace 8, etc.

[0047] An oilfield steam injection boiler plunger pump protection process described in the present invention has a process flow as Figure 1 follows: The high-temperature recycled and purified sewage enters the air cooler 2 after being treated by the water treatment system 1. The high-temperature recycled and purified sewage exchanges heat with the air in the air cooler 2. After the high-temperature recycled and purified sewage is cooled, it enters the plunger pump 3, and the hot air enters the furnace 8 to assist fuel combustion. The recycled and purified sewage after temperature reduction is transported to the boiler water-water heat exchanger 6 by the plunger pump 3. After adjusting the temperature in the boiler water-water heat exchanger 6, it enters the boiler convection heating surface 5 and the boiler radiation heating surface 4. After absorbing heat in the boiler convection heating surface 5 and the boiler radiation heating surface 4, the recycled and purified sewage becomes qualified steam and is then transported to the oilfield steam injection pipe network 9.

[0048] The oilfield steam injection boiler plunger pump protection process described in this invention patent has a process flow as Figure 2, it can also be: the high-temperature recycled sewage is cooled by the air cooler 2 and then enters the water treatment system 1. After being treated by the water treatment system 1, it is transported to the water-water heat exchanger 6 by the plunger pump 3. The recycled purified sewage adjusts its temperature in the water-water heat exchanger 6, absorbs heat in the boiler convection heating surface 5 and the boiler radiation heating surface 4, and then becomes qualified steam and is transported to the oilfield steam injection pipeline network 9. Air is transported to the air cooler 2 by the blower 7, heated in the air cooler 2, and then sent into the furnace 8 to assist fuel combustion.

[0049] The air cooler 2 described in the present invention is adopted according to the actual situation but is not limited to a tubular air cooler (such as Figure 3 ), a heat pipe air cooler (such as Figure 5 ) and other forms.

[0050] The tubular air cooler described in the present invention adopts a horizontal or vertical structure. The recycled purified sewage flows inside the tubes, and air flows outside the tubes. The recycled purified sewage and air adopt a single-pass or multi-pass structure according to the actual situation (such as Figure 4 ), and the heat exchange tube bundle 10 is adopted according to the actual situation but is not limited to structures such as plain tubes, fin tubes, finned tubes, and stud tubes.

[0051] The heat pipe air cooler described in the present invention adopts a horizontal or vertical structure. The recycled sewage flows inside the tubes, and air flows outside the tubes. The heat exchange tube bundle 10 is adopted according to the actual situation but is not limited to structures such as plain tubes, fin tubes, finned tubes, and stud tubes.

[0052] Embodiment

[0053] Embodiment 1: For an 11.2t / h oilfield fuel (gas) steam injection boiler in Liaohe Oilfield, the temperature of the recycled purified sewage of the boiler is 70°C, the rated steam pressure at the boiler outlet is 21MPa, and the rated steam dryness at the boiler outlet is 80%. Adopting the process provided by the present invention, a tubular air cooler is added after the water treatment system, and the temperature of the recycled sewage is reduced from 70°C to 60°C. Its process flow (such as Figure 1 ) is:

[0054] Process flow of the boiler steam-water system: recycled purified sewage → water treatment system 1 → air cooler 2 → plunger pump 3 → water-water heat exchanger 6 → boiler convection heating surface 5 → water-water heat exchanger 6 → boiler radiation heating surface 4 → oilfield steam injection pipeline network 9;

[0055] Process flow of the boiler flue gas and air system: blower 7 → air cooler 2 → furnace 8 → boiler radiation heating surface 4 → boiler convection heating surface 5 → atmosphere.

[0056] After the boiler transformation: the water temperature at the inlet of the plunger pump is reduced from 70°C to 60°C; the air inlet temperature to the furnace is increased from 20°C to 70°C; the boiler flue gas temperature is reduced from 123°C to 115°C; the boiler thermal efficiency is increased from 92.9% to 93.4%, an increase of 0.4%; the natural gas consumption of the boiler is reduced from 61.4m3 / t steam is reduced to 61.1 m 3 / t steam, a 0.4% reduction, and the direct CO emissions from boiler fuel combustion 2 are reduced from 118 kg / t CO 2 steam to 117 kg / t CO 2 steam, a 0.4% reduction.

[0057] The newly added heat exchange tubes 10 of the tubular air cooler adopt a finned tube structure, and the heat exchange area is 350 m 2 .

[0058] Example 2: For an 11.2 t / h oilfield fuel (gas) steam injection boiler in an oilfield in Xinjiang, the temperature of the recycled purified sewage of the boiler is 90°C, the rated steam pressure at the boiler outlet is 21 MPa, and the rated steam dryness at the boiler outlet is 80%. Using the process provided by this invention patent, a tubular air cooler is added in front of the water treatment system to reduce the temperature of the recycled sewage to 76°C. Its process flow (as Figure 2 ) is as follows:

[0059] Boiler steam and water flow: Recycled purified sewage → Air cooler 2 → Water treatment system 1 → Plunger pump 3 → Water-water heat exchanger 6 → Convective heating surface 5 of the boiler → Water-water heat exchanger 6 → Radiant heating surface 4 of the boiler → Oilfield steam injection pipeline network 9;

[0060] Boiler flue gas and air flow: Blower 7 → Air cooler 2 → Furnace 8 → Radiant heating surface 4 of the boiler → Convective heating surface 5 of the boiler → Atmosphere.

[0061] After the boiler transformation: The water temperature at the inlet of the plunger pump is reduced from 90°C to 76°C; the air inlet temperature to the furnace is increased from 20°C to 90°C; the boiler flue gas temperature is reduced from 136°C to 125°C; the boiler thermal efficiency is increased from 92.4% to 92.9%, an increase of 0.5%; the natural gas consumption of the boiler is reduced from 59.1 m 3 / t steam to 58.8 m 3 / t steam, a 0.5% reduction; the direct CO emissions from boiler fuel combustion 2 are reduced, from 113 kg / t CO 2 steam to 112 kg / t CO 2 steam, a 0.5% reduction.

[0062] The newly added heat exchange tubes 10 of the tubular air cooler adopt a finned tube structure, and the heat exchange area is 290 m 2 .

[0063] The protection process of the plunger pump of the oilfield steam injection boiler described in the present invention uses the heat of high-temperature recycled purified sewage to heat the air for boiler combustion, reducing the water temperature entering the plunger pump 3 of the boiler, which is essentially different from the existing process (patent application number: 201820992537.4) that uses dry air to reduce the temperature of the recycled purified sewage in the boiler.

[0064] The protection process of the plunger pump of the oilfield steam injection boiler of the present invention uses the heat of high-temperature recycled purified sewage to heat the air for boiler combustion, reducing the temperature of the recycled purified sewage entering the plunger pump 3 of the boiler, reducing the failure rate of the plunger pump 3, and solving the problem of frequent start-stop of the boiler caused by high-temperature recycled sewage; secondly, it increases the air temperature entering the boiler furnace, reducing the fuel consumption of the boiler; and it improves the regulation ability of the boiler water-water heat exchanger, reducing the boiler flue gas temperature and increasing the boiler thermal efficiency.

Claims

1. Oilfield steam injection boiler plunger pump protection process, characterized by Includes the following hardware equipment: water treatment system, air cooler, plunger pump, boiler radiation heating surface, boiler convection heating surface, boiler water-water heat exchanger, blower and furnace; The process flow of the protection process is: (1) Cooling down the high-temperature reused purified wastewater in an air cooler; (2) The air is transported to the air cooler through the blower, and the high-temperature recycled purified wastewater exchanges heat with the air in the air cooler. The hot air enters the furnace to assist the combustion of the fuel; (3) The high-temperature recycled purified sewage is cooled and then enters the plunger pump; (4) The cooled recycled purified sewage is transported to the boiler water-water heat exchanger via a plunger pump; (5) After the temperature of the recycled purified wastewater is adjusted in the boiler water-water heat exchanger, it enters the boiler convection heating surface and the boiler radiation heating surface. After the recycled purified wastewater absorbs heat on the boiler convection heating surface and the boiler radiation heating surface, it becomes qualified steam and is then transported to the oil field steam injection pipeline network.

2. The oilfield steam injection boiler plunger pump protection process according to claim 1 is characterized in that In the step (1), during the cooling treatment of the high-temperature reused purified sewage, the high-temperature reused purified sewage is treated by the water treatment system and then enters the air cooler, or the high-temperature reused sewage is cooled by the air cooler and then enters the water treatment system.

3. The oilfield steam injection boiler plunger pump protection process according to claim 1 is characterized in that The air cooler is a tubular air cooler or a heat pipe air cooler.

4. The oilfield steam injection boiler plunger pump protection process according to claim 3 is characterized in that The tubular air cooler adopts a horizontal or vertical structure, the recycled purified sewage flows in the tube, and the air flows outside the tube. The recycled purified sewage and air adopt a single-return or multi-return structure.

5. The oilfield steam injection boiler plunger pump protection process according to claim 3 is characterized in that The heat pipe type air cooler adopts a horizontal or vertical structure, the recycled sewage flows in the pipe, and the air flows outside the pipe.

6. The oilfield steam injection boiler plunger pump protection process according to claim 3 is characterized in that The heat exchange tube bundle of the tubular air cooler or heat pipe air cooler adopts a structure of a plain tube, a finned tube, a finned tube or a nail head tube.

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