CN204755145U - Boats and ships fuel system of preheating - Google Patents

Abstract

The utility model relates to a fuel oil preheating system for a ship, which is characterized in that: two branch pipelines for fuel oil preheating and transportation are arranged between the storage cabin and the settling tank, the main pipeline is shared, and two branch lines are divided near the settling tank, One path is equipped with a preheat pump to provide high-temperature fuel for the storage compartment, and the other path is equipped with a transfer pump to transport the heated heavy oil to the settling tank. Both branches are equipped with cut-off check valves in the corresponding direction to prevent misalignment of the pipeline direction; in the storage compartment A small compartment is set at one corner, and a first partition is set in the middle of the small compartment, which divides the compartment into two in the X direction, and the A and B pipes are arranged in the first subdivision; the upper right corner of the first partition has a hole, and the second There is a hole in the lower left corner of the second partition, and the two holes are arranged diagonally; a small hole is opened at the bottom of the partition for cabin stripping; a number of air holes are set on the upper plate of the partition to ensure the timely overflow of the generated steam; the A and B pipes It communicates with the main pipeline, and the A and B pipelines are respectively equipped with regulating valves.

Description

A ship fuel oil preheating system

technical field

The utility model relates to a ship fuel oil preheating system, which belongs to the technical field of ship fuel oil preheating.

Background technique

In the ship's fuel oil delivery system, it is necessary to transport the fuel oil from the storage tank to the settling tank. The fuel oil in the storage tank is generally heavy fuel oil, and its viscosity varies greatly with temperature. The higher the temperature, the lower the viscosity. For example, the viscosity of a certain type of heavy fuel oil is 380cSt at 50°C, and close to 20000cSt at 0°C. The high viscosity will lead to a large resistance when the transfer pump pumps fuel, which will increase power consumption and even make it impossible to pump. Therefore, it is necessary to pre-heat the fuel to a certain temperature to reduce the viscosity before pumping.

At present, the traditional heating method for heavy oil on ships is to arrange heating coils in the fuel oil tanks on both sides of the ship, and heat the heavy oil through steam to achieve lightering conditions, as shown in Figure 1. The heating coil is used to heat the heavy oil, and when the transportation condition is reached, the valve is opened to suck the fuel oil out from the suction port.

This mode has obvious disadvantages: 1) the energy utilization rate is low. The coil heats the entire tank of fuel, but the actual amount of fuel that needs to be pumped is relatively small compared to the volume of the fuel storage tank, so a considerable part of the heat is used to heat the fuel that does not need to be pumped, and this part of heat is easy to pass through the bulkhead and the outside world is wasted for heat exchange. 2) A large range of high temperature zones will be generated. When the storage tank is adjacent to the ballast tank or cargo tank, the high temperature of the ballast bulkhead will accelerate the occurrence of corrosion, and it will also cause damage to temperature-sensitive cargo, such as grain and coal. 3) When the fuel level is lower than the heating coil, the coil exposed to the air will accelerate the volatilization of gas and form hard scale. 4) The height of the heating coil arrangement should not be too low. When the fuel level is completely lower than the heating coil, the fuel will be difficult to be transported, resulting in fuel retention.

In order to solve the problems caused by the heating coil in the fuel delivery system, a new type of fuel conversion device has also appeared in the prior art. The main design idea is: a small compartment is set in the fuel storage compartment, and the compartment communicates with the storage compartment. First pump the high-temperature fuel in the settling tank into the small compartment, preheat to obtain a certain amount of relatively high-temperature fuel to meet the pumping conditions, and then use the fuel delivery pump to pump the fuel to the settling tank, and so on. Figure 2 shows a schematic diagram of the compartment scheme in the fuel storage tank. The main purpose of the compartment design is to make the injected hot fuel mainly be used to heat the cold fuel in a local area as much as possible, and to control the heated fuel so as not to disperse too much, but to concentrate in the small compartment, so that the extracted fuel is Relatively hot fuel for easy pumping.

Although this fuel conversion device can better avoid the problems caused by coil heating and save operating costs, it also has disadvantages—the preheating effect depends on the design of the compartment scheme, and unreasonable isolation The tank design may lead to problems such as uneven distribution of fuel oil temperature in the compartment, accumulation of hot oil above the compartment, insufficient heat exchange between hot and cold oil, and low oil temperature near the suction port, which will weaken its effectiveness compared with the traditional coil heating method. Advantages, when the operating conditions deteriorate, it may even increase operating costs, and even the economy is inferior to coil heating. Therefore, a reasonable compartment scheme design is the key to the entire fuel preheating system.

Utility model content

The technical problem to be solved by the utility model is: the compartment design of the fuel oil conversion device in the existing ship fuel oil preheating system leads to uneven distribution of fuel oil temperature in the compartment, accumulation of hot oil above the compartment, and heat exchange between hot and cold oil. Insufficient, low oil temperature near the suction port, etc., may even increase operating costs when the operating conditions deteriorate, and even the economy is inferior to coil heating.

The utility model takes the following technical solutions:

A fuel oil preheating system for a ship. Two branch pipelines for fuel oil preheating and delivery are set between the storage tank and the settling tank. The main pipeline is shared, and it is divided into two branches near the settling tank. High-temperature fuel is provided, and a delivery pump is installed on the other side to transport the heated heavy oil to the settling tank. Both branches are equipped with cut-off check valves in the corresponding direction to prevent misalignment of the pipeline direction; The first partition 1 is set in the middle of the small compartment, which divides the compartment into two in the X direction, and the A and B pipes are arranged in the first subdivision 1; the upper right corner of the first partition is opened, and the lower left corner of the second partition is opened. Two holes are arranged diagonally; a small hole is opened at the bottom of the partition for cabin stripping; a number of ventilation holes are arranged on the upper plate of the compartment to ensure that the generated steam overflows in time; the A and B pipes are connected with the main pipeline , A and B pipelines are respectively equipped with regulating valves.

This technical solution optimizes the design of the fuel conversion device in the prior art. The first partition is used to divide the small compartment into two in the X direction, and a small hole is opened in the upper right corner of the first partition and the lower left corner of the second partition. , the purpose is to increase the distance of the moving track of the fuel in the small compartment as much as possible under the premise of using a small compartment with a volume as small as possible to improve the heat utilization efficiency, so as to improve the heat exchange efficiency. Fuel oil has the characteristic of downward flow, and the outlets of oil pipes A and B are close to the bottom, while the oil outlet of the first subdivision is located in the upper right corner, and the oil outlet of the second subdivision is located in the lower left corner, thereby increasing the distance traveled by hot oil. Improve the heat exchange effect and uniformity of hot and cold oil in the small compartment. The two oil pipes A and B can be used alternately. The fuel preheating system of a single pipe cannot achieve a good preheating effect. The temperature of the nearby fuel oil dropped sharply, and the pumping conditions could not be reached. The use of dual pipeline design can effectively solve this problem.

Further, the pipes A and B are centrally arranged in the first subdivision 1 along the X direction.

Further, the nozzle can be as close to the bilge as possible under the condition that the hot oil does not damage the bilge, but not too close to avoid excessive flow resistance.

Further, the nozzles of the pipelines A and B have the same height in the small compartment.

A method for preheating fuel oil for ships, using the above-mentioned fuel oil preheating system for ships, comprising the following steps:

A) The high-temperature fuel flow Qv1 is injected into the small compartment by the preheat pump through the oil pipe B and the temperature is T during the time t1;

B) The delivery pump sucks the fuel oil through the oil pipe B and sends it to the settling tank, the duration is t2, and the flow rate is Qv1;

C) Inject high-temperature fuel oil with temperature T at time t3 from the preheat pump through oil pipe A to the compartment, and the flow rate is Qv2;

D) The delivery pump sucks the fuel oil through the oil pipe B and sends it to the settling tank, the duration is t2, and the flow rate is Qv1;

E) Taking t3+t2 as the period, repeat steps C)-D).

The selection of the pipeline is realized by the opening and closing of the regulating valve, and the ratio of the injection time is selected according to the flow rate and the temperature of the fuel.

The function of steps A and B is to preheat the fuel near the fuel pipe B in the small compartment in time at the beginning of the startup, because the fuel near the fuel pipe A has not had time to be heated at the beginning of the startup, after the two steps A and B are completed , step C and step D can be reciprocated.

The beneficial effects of the utility model are:

1) Green and energy-saving, reducing operating costs. Since only part of the fuel oil is heated, and the heat is effectively used, the heat exchange with the outside world is reduced, which is in line with the concept of green energy saving and can effectively reduce the operating cost of the ship.

2) Avoid the scaling, steam leakage, fuel retention and other problems caused by the heating coil, and avoid the installation and maintenance of the coil heating system.

3) It will not cause damage to adjacent cargo due to high temperature of fuel oil storage tanks, nor will it cause corrosion of ballast tanks.

4) Different from the coil heating the whole fuel tank, this design only needs to heat the cold oil in a local area, so the heating speed is faster than the coil method, and the system is simple, stable and easy to operate.

5) Compared with the fuel conversion device in the prior art, the double-pipe design can effectively extend the heat exchange time of cold and hot heavy oil, obtain more fuel oil that meets the pumping conditions, and improve the utilization rate of heat.

6) Double-pipe compartment setting. The compartment can make the heat be mainly used to heat the cold oil in the compartment, so that the heated oil is still relatively concentrated in the compartment, which is convenient for transportation;

7) Alternate use of two oil pipes and injection and drainage scheme. Through numerical calculation, it is found that the fuel preheating system with a single pipeline cannot achieve a good preheating effect, because the high-temperature fuel that has just been injected is drawn out before it can exchange heat with the cold oil, resulting in a sharp drop in the temperature of the fuel near the suction port. , can not meet the pumping conditions. The use of dual pipeline design can effectively solve this problem.

8) Diagonal arrangement of the through-holes in the partition. It can better solve the problem of hot oil in the dead zone, effectively increase the heat exchange stroke of hot and cold oil and prolong the time of hot oil staying in the compartment, and strengthen the heat exchange effect.

Description of drawings

Fig. 1 is a schematic diagram of a fuel preheating system using coil heating in the prior art.

Fig. 2 is a schematic diagram of a fuel preheating system using a fuel conversion device in the prior art.

Fig. 3 is a flow chart of the schematic diagram of the fuel oil preheating system of the utility model.

Fig. 4 is a schematic diagram of the small compartment design of the fuel oil preheating system of the utility model.

In the figure, 1. the first subdivision, 2. the first partition, 3. the second subdivision, 4. the second partition.

Detailed ways

Below in conjunction with accompanying drawing and specific embodiment the utility model is further described.

The specific design scheme of the utility model is shown in Figure 3: two pipelines for fuel oil preheating and transportation are set between the fuel storage tank and the fuel oil sedimentation tank. The main pipelines are shared, and they are divided into two branches near the sedimentation tank. The fuel preheating pump provides high-temperature fuel for the storage tank. A fuel transfer pump is installed along the way to transport the heated heavy oil to the settling tank. Both branches are equipped with cut-off check valves in corresponding directions to prevent misalignment of the pipeline direction. In order to cooperate with the compartment scheme and make the compartment have a better fuel preheating effect, this design sets two pipelines of the same height in the small compartment, and each is equipped with a regulating valve.

The design of the compartment scheme is shown in Figure 4: a small compartment is set in a corner of the fuel storage tank, adjacent to non-ballast tanks, cargo tanks and other places that are easily affected by high temperature, and its volume depends on the displacement of the preheat pump and the fuel consumption of the diesel engine; A partition is set in the middle to divide the compartment into two. The A and B pipes are arranged in the first subdivision, arranged in the center along the X direction, and arranged near the quarters along the Y direction, so that the hot oil will not damage the bilge Under the circumstances, the nozzle can be as close as possible to the bilge, but not too close to avoid excessive flow resistance; the opening at the upper right corner of the first partition and the opening at the lower left corner of the second partition are arranged diagonally; the opening at the bottom of the partition The small hole is used for stripping the cabin (not shown in the figure); the upper plate of the compartment is provided with a number of ventilation holes (not shown in the figure) to ensure the timely overflow of the generated steam.

The specific operation steps are:

A) The preheat pump injects high-temperature fuel oil for t1 time into the compartment through oil pipe B, and the flow rate is Qv1;

B) The delivery pump sucks the fuel oil through the oil pipe B and sends it to the settling tank, the duration is t2, and the flow rate is Qv1;

C) Inject t3 high-temperature fuel into the compartment through the oil pipe A from the preheat pump, and the flow rate is Qv2;

D) The delivery pump sucks the fuel oil through the oil pipe B and sends it to the settling tank, the duration is t2, and the flow rate is Qv1;

E) With t3+t2 as the period, arrange C-D cyclically.

The selection of the pipeline is realized by the opening and closing of the regulating valve, and the ratio of the pumping time is related to the flow rate and the temperature of the fuel.

The purpose of this utility model is to exchange heat between the injected hot oil and cold oil to obtain relatively high-temperature fuel oil that meets the pumping conditions. This design takes the fuel oil t=40°C as the suitable delivery standard. Therefore, how to make the heat exchange between hot oil and cold oil sufficiently to obtain as much relatively high-temperature fuel as possible, and how to make the heat mainly used to heat the fuel in a certain area is very important. In view of this, key point of the present utility model is:

Double tube compartment setup. The compartment enables the heat to be mainly used to heat the cold oil in the compartment, so that the heated oil is relatively concentrated in the compartment for easy transportation; and whether the arrangement of double pipes and partitions is reasonable or not will affect the fuel preheating effect.

Alternate use of two oil pipes and injection and drainage scheme. Numerical calculations show that the fuel preheating system with a single pipeline cannot achieve a good preheating effect. The reason is that the high-temperature fuel that has just been injected is drawn out before it can exchange heat with the cold oil, resulting in a sharp drop in the temperature of the fuel near the suction port. , can not meet the pumping conditions. The use of dual pipeline design can effectively solve this problem.

Diagonal arrangement of through-holes in the bulkhead. It can better solve the problem of hot oil in the dead zone, effectively increase the heat exchange stroke of hot and cold oil and prolong the time of hot oil staying in the compartment, and strengthen the heat exchange effect.

Claims (4)

1. A ship fuel oil preheating system, characterized in that: Set up two branch pipelines for fuel preheating and delivery between the storage tank and the settling tank. The main pipeline is shared. It is divided into two branches near the settling tank. A preheat pump is installed on one side to provide high-temperature fuel for the storage tank, and the other is set up to convey The pump transports the heated heavy oil to the settling tank, and the two branches are equipped with stop check valves in the corresponding direction to prevent the misalignment of the pipeline direction; A small compartment is set at one corner of the storage cabin, and a first partition (2) is arranged in the middle of the small compartment, which divides the compartment into two in the X direction, and the A and B pipes are arranged in the first sub-compartment (1); A hole is opened in the upper right corner of one partition, and a hole is opened in the lower left corner of the second partition, and the two holes are arranged diagonally; small holes are opened at the bottom of the partition for cabin stripping; a number of ventilation holes are set on the upper plate of the compartment to ensure that the generated steam overflow in time; The A and B pipes are in communication with the main pipeline, and the A and B pipelines are respectively provided with regulating valves. 2. The marine fuel oil preheating system according to claim 1, characterized in that: A and B pipes are centrally arranged in the first subdivision (1) along the X direction. 3. The marine fuel oil preheating system according to claim 1, characterized in that the nozzle can be as close to the bilge as possible under the condition that the hot oil does not damage the bilge, but not too close to avoid excessive flow resistance. 4. The marine fuel oil preheating system according to claim 1, characterized in that: the nozzles of the A and B pipelines have the same height in the small compartment.