Lubricating oil cooling system of centrifugal compressor

Abstract

The utility model relates to a lubricating oil cooling system of a centrifugal compressor, which comprises two water inlet pipelines, one pipeline is a normal-temperature cooling water inlet pipeline in the prior art, and the other pipeline is a low-temperature cooling water inlet pipeline additionally arranged in the lubricating oil cooling system. The low-temperature cooling water inlet pipeline comprises a branch pipe led out behind the normal-temperature circulating cooling water pump and in front of the cooling water regulating valve, the branch pipe is sequentially connected with low-temperature cooling water production equipment, a low-temperature cooling water pump and the low-temperature cooling water regulating valve, and a pipeline outlet is connected behind the normal-temperature cooling water regulating valve and in front of the centrifugal compressor lubricating oil cooler; the utility model solves the problem that the temperature of lubricating oil is high when a fan of a circulating cooling water system breaks down or equipment is regularly repaired or the temperature of the lubricating oil is high in summer, simultaneously, the existing technical process and equipment are substantially improved by utilizing the existing process conditions of a production field, and a remarkable technical effect is achieved.

Description

Technical Field

[0001] The utility model belongs to the field of deep cooling air separation, in particular to the process design and manufacture of a centrifugal compressor lubricating oil system in this field. Background Art

[0002] In the field of cryogenic air separation, centrifugal compressors are used to compress and transport various industrial gases such as air, oxygen, and nitrogen. Their lubricating oil system mainly consists of an oil tank, an oil pump, an oil filter, an oil cooler, an oil mist separator, and an oil pressure regulating valve.

[0003] The working principle of its lubricating oil system is that the lubricating oil is extracted from the oil tank, compressed by the oil pump, filtered through the oil filter, cooled to the set value in the oil cooler, and delivered to the compressor and main motor bearings. After lubricating, cooling and cleaning the bearings, it returns to the oil tank.

[0004] The oil coolers in the prior art are mostly tubular heat exchangers. The tube side of the lubricating oil cooler is cooling water, and the shell side is lubricating oil. The normal temperature tube side cooling water exchanges heat with the high temperature shell side lubricating oil. The cooling water at the tube side outlet is heated up, and the lubricating oil at the shell side outlet is cooled down. The prior art centrifugal compressor lubricating oil coolers in the air separation field are usually designed with one channel of normal temperature cooling water. A water inlet valve is set at the cooling water inlet end to adjust the cooling water flow of the lubricating oil cooler. When the temperature of the circulating cooling water rises, the valve opening of the lubricating oil cooler water inlet valve is increased, the cooling water flow in the lubricating oil cooler is increased, the lubricating oil temperature is reduced, and the centrifugal compressor bearing temperature is prevented from being higher than its design value. When the temperature of the circulating cooling water decreases, the valve opening of the lubricating oil cooler water inlet valve is reduced, the cooling water flow in the lubricating oil cooler is reduced, and the lubricating oil temperature is not allowed to be lower than its low alarm value, thereby preventing the lubricating oil viscosity from increasing and controlling the vibration value of the centrifugal compressor bearing.

[0005] Production lines operating centrifugal compressors are equipped with a circulating cooling water system to provide circulating cooling water for the centrifugal compressors and their production line equipment. The circulating cooling water system consists of purification equipment, a water storage tank, a cooling fan, and a water pump. The circulating cooling water is cooled by the cooling fan and pressurized by the water pump. Some of this circulating cooling water is then delivered to the centrifugal compressor's gas cooler, where it exchanges heat with the high-temperature, pressurized industrial gas at the centrifugal compressor's impeller and diffuser outlet, cooling the compressed gas. Simultaneously, some of this circulating cooling water is delivered to the centrifugal compressor's lubricating oil cooler, where it exchanges heat with the high-temperature, pressurized lubricating oil at the oil pump outlet, cooling the lubricating oil.

[0006] The reference ambient temperature parameters for the design load and number of cooling fans in the circulating cooling water systems of the existing centrifugal compressors and their related production lines are mainly based on the average ambient temperature throughout the year. As a result, when the temperature is low in winter, the design load and number of cooling fans are redundant, and the circulating cooling water temperature is low. The circulating cooling water temperature can be effectively controlled by adjusting the load and number of cooling fans. However, when the temperature is high in summer, especially when there is a sudden cooling fan failure or during equipment maintenance, the cooling fan load is insufficient, the circulating cooling water temperature is high, and the circulating cooling water temperature cannot be effectively controlled.

[0007] During high temperatures in summer, even if the cooling fan of the circulating cooling water system is kept at the maximum design load and in full operation, and the water inlet valve of the lubricating oil cooler is fully opened to increase the cooling water flow rate of the lubricating oil cooler pipe side to the maximum design value, the temperature of the cooling water entering the lubricating oil cooler pipe side increases due to the increase in ambient temperature, the cooling effect of the lubricating oil is poor, the lubricating oil temperature at the shell side outlet of the lubricating oil cooler reaches or exceeds its high temperature alarm value, the bearing temperature of the centrifugal compressor is greater than its design value, the full cycle service time of the bearing is shortened, and the failure rate is high, resulting in low safety and stability of the equipment during high temperature operation in summer.

[0008] If the cooling fan fails or the equipment is scheduled for repair, the operating load or number of cooling fans in the circulating cooling water system will be reduced. Fully open the lubricating oil cooler inlet valve to increase the cooling water flow rate in the lubricating oil cooler tubes to the maximum design value. Due to the reduction in the operating load or number of cooling fans, the cooling water temperature entering the lubricating oil cooler tubes will increase, significantly reducing the lubricating oil cooling effect. The lubricating oil temperature at the lubricating oil cooler shell-side outlet will exceed its high temperature alarm value or reach the interlock shutdown value. The centrifugal compressor bearing temperature will exceed its high temperature alarm value or reach the interlock shutdown value.

[0009] Our company's 35000m 3 / h air separation unit as an example, see Figure 1 , our company 35000m 3 / h air separation unit is equipped with a centrifugal single-shaft isothermal oxygen compressor imported from abroad, which consists of a main motor, a speed increaser, and a compressor. The main motor, speed increaser, and compressor are equipped with 2, 4, and 6 pairs of bearings respectively. 3 / h air separation unit is equipped with a circulating cooling water system to provide circulating cooling water for the centrifugal air compressor, oxygen compressor, nitrogen compressor, air cooling tower and nitrogen-water cooling tower of the air separation unit. In July 2021, all three cooling fans of the circulating cooling water system were in operation, and the load of the three cooling fans was adjusted to 100%. The circulating cooling water supply temperature was greater than 34.5°C, which was 28°C higher than the design value. The lubricating oil temperature of the centrifugal oxygen compressor was greater than the high alarm value of 50°C. The temperatures of the main motor, speed increaser and compressor bearings were all greater than the design value range of 85°C. In particular, the temperature of the high-speed side bearing of the speed increaser was greater than the high alarm value of 100°C. The centrifugal oxygen compressor was in operation until September 2021, when it was shut down for scheduled maintenance, the speed increaser was disassembled, and the high-speed side bearing was replaced. Utility Model Content

[0010] (1) Technical problems solved

[0011] In view of the defects of the existing technology, in order to completely solve the phenomenon that the lubricating oil temperature of the centrifugal compressor reaches or exceeds the high alarm value, and avoid the centrifugal compressor bearing failure or automatic shutdown due to rising to the interlock value, the purpose of the utility model is to provide a centrifugal compressor lubricating oil cooling process and equipment. When the circulating cooling water temperature is higher than the design value, the cooling water temperature in the lubricating oil cooler pipe is reduced, and the centrifugal compressor bearing temperature is kept within the design value range, ensuring the safe, stable and long-term operation of the centrifugal compressor.

[0012] (2) Technical solution

[0013] In order to achieve the above objectives, the present invention is implemented through the following technical solutions:

[0014] The process described in this utility model is to design a centrifugal compressor lubricating oil cooling process based on the heat exchange principle and structural characteristics of the centrifugal compressor lubricating oil cooler. By adding a low-temperature cooling water process to the centrifugal compressor lubricating oil cooler's water inlet pipeline, the cooling water temperature in the lubricating oil cooler is reduced. The centrifugal compressor lubricating oil cooler is designed to have a two-way cooling water inlet process, one of which is the original design of the lubricating oil cooler's normal temperature cooling water, and the other is the added low-temperature cooling water.

[0015] The utility model discloses a centrifugal compressor lubricating oil cooling system, the cooling system includes a normal temperature cooling water inlet pipeline system, the normal temperature cooling water inlet pipeline system includes a pipeline leading out of a circulating cooling water cooling tower, the pipeline is sequentially connected to a normal temperature circulating cooling water pump and a centrifugal compressor lubricating oil cooler, a normal temperature cooling water regulating valve is installed between the normal temperature circulating cooling water pump and the centrifugal compressor lubricating oil cooler for control; on the basis of the existing technology, the technical solution of the utility model adds another low temperature cooling water inlet pipeline system, including leading out a branch pipe after the normal temperature circulating cooling water pump and before the cooling water regulating valve, the branch pipe is sequentially connected to the low temperature cooling water Cooling water production equipment, low-temperature cooling water pump, low-temperature cooling water regulating valve, the pipeline outlet is connected to the normal temperature cooling water regulating valve and before the centrifugal compressor lubricating oil cooler; that is, a two-way cooling water inlet pipeline system is formed in front of the lubricating oil cooler, one way is the normal temperature cooling water inlet pipeline of the existing technology, and the other way is the added low-temperature cooling water inlet pipeline, the low-temperature cooling water inlet pipeline is connected to the normal temperature cooling water inlet pipeline, the two inlet pipelines are combined into one inlet pipeline connected to the inlet of the centrifugal compressor lubricating oil cooler, and an outlet pipe is drawn out from the centrifugal compressor lubricating oil cooler and connected to the circulating cooling water cooling tower to form a circulating cooling water closed-loop pipeline.

[0016] When the lubricating oil temperature of the centrifugal compressor is not greater than the design value, the lubricating oil cooler uses the originally designed normal temperature cooling water to cool the lubricating oil. When the lubricating oil temperature is greater than the design value, the low-temperature cooling water inlet valve is opened to input the low-temperature cooling water into the lubricating oil cooler inlet pipe to reduce the cooling water temperature in the lubricating oil cooler pipe so that the lubricating oil temperature is within the design value range.

[0017] There are two ways to produce low-temperature cooling water in the above technical solution. One is that the low-temperature cooling water production equipment is a chiller, and part of the normal-temperature cooling water in the pipeline after the normal-temperature circulating cooling water pump of the circulating cooling water system is transported to the chiller through the branch pipeline to cool it into low-temperature cooling water, and then input into the low-temperature cooling water inlet pipeline; the other is that the low-temperature cooling water production equipment is the refrigeration equipment of the production line to which the centrifugal compressor belongs, and a small amount of low-temperature cooling water is extracted from the redundant amount of the refrigeration equipment and input into the low-temperature cooling water inlet pipeline.

[0018] According to the characteristics of the production line to which the centrifugal compressor belongs and the number of centrifugal compressor lubricating oil coolers, the low-temperature cooling water production equipment is selected. The low-temperature cooling water production equipment includes: one is a dedicated chiller to provide low-temperature cooling water, and the other is the production line to which the centrifugal compressor belongs, which extracts a small amount of low-temperature cooling water from the production line to which the centrifugal compressor belongs without affecting the stable production state.

[0019] When the production line to which the centrifugal compressor belongs cannot provide low-temperature cooling water or there are a large number of centrifugal compressor lubricating oil coolers and the demand for additional low-temperature cooling water flow is high, a dedicated chiller can be set up, and a low-temperature cooling water pump can be set up at the outlet of the chiller. The dedicated chiller provides low-temperature cooling water, and part of the normal-temperature cooling water transported by the circulating cooling water system is cooled to low-temperature cooling water, while cooling the lubricating oil of multiple centrifugal compressor lubricating oil coolers.

[0020] If the production line to which the centrifugal compressor belongs can provide low-temperature cooling water, and the number of centrifugal compressor lubricating oil coolers is small, and the demand for low-temperature cooling water flow is low, a small amount of low-temperature cooling water is extracted from the production line to cool the lubricating oil in the centrifugal compressor lubricating oil cooler; the low-temperature cooling water pressure added to the lubricating oil cooler is designed to be higher than the normal-temperature cooling water pressure, and the added low-temperature cooling water flow is the same as the normal-temperature cooling water flow originally designed for the lubricating oil cooler, and the added low-temperature cooling water is stably fed into the lubricating oil cooler. Different types of production lines provide different types of low-temperature cooling water. Select low-temperature cooling water that is pressurized at the outlet of the production line's process low-temperature water pump to ensure that the added low-temperature cooling water pressure is higher than the circulating normal-temperature cooling water pressure.

[0021] The diameter of the low-temperature cooling water pipeline of the utility model is the same as that of the normal-temperature cooling water pipeline. The low-temperature cooling water pipeline is made of stainless steel. The low-temperature cooling water pneumatic regulating valve has the same diameter as the low-temperature cooling water delivery pipeline, which reduces the low-temperature cooling water delivery resistance. The normal-temperature cooling water regulating valve and the low-temperature cooling water regulating valve are both pneumatic sleeve-type regulating valves. This type of valve has a short response time for regulating the cooling water flow, high accuracy, and small pressure drop, so that the lubricating oil temperature is within the design value range and the temperature fluctuation value is small.

[0022] A further technical solution of the utility model is to electrically connect the normal temperature cooling water regulating valve, the low temperature cooling water regulating valve, and the lubricating oil thermometer at the shell side outlet of the lubricating oil cooler to the DCS and PLC automatic control system of the centrifugal compressor or the production line to which it belongs. According to the lubricating oil temperature set value, the normal temperature cooling water pneumatic regulating valve and the low temperature cooling water pneumatic regulating valve automatically control the valve opening to adjust the flow rate of the normal temperature cooling water and the low temperature cooling water input into the lubricating oil cooler.

[0023] The automatic control logic of the centrifugal compressor lubricating oil temperature is divided into three steps. In step one, when the lubricating oil temperature is not greater than the set value, the normal temperature cooling water pneumatic regulating valve automatically opens according to the lubricating oil temperature set value, and the normal temperature cooling water is input into the lubricating oil cooler to make the lubricating oil temperature within the set value range; in step two, when the lubricating oil temperature rises to greater than the set value or reaches the high alarm value, the low temperature cooling water pneumatic regulating valve automatically opens, and the low temperature cooling water is input into the lubricating oil cooler to reduce the lubricating oil temperature to the set value range; in step three, when the lubricating oil temperature drops to the low alarm value, the low temperature cooling water pneumatic regulating valve automatically closes, the low temperature cooling water stops inputting into the lubricating oil cooler, and the normal temperature cooling water pneumatic regulating valve automatically adjusts the valve opening to raise the lubricating oil temperature to the set value range.

[0024] The utility model provides a centrifugal compressor lubricating oil cooling process and equipment. By adding a low-temperature cooling water process to the original normal-temperature cooling water pipeline at the water inlet end of the centrifugal compressor lubricating oil cooler, the utility model completely solves the problem of high lubricating oil temperature during operation of the centrifugal compressor when the fan of the circulating cooling water system fails or the equipment is under repair, or under high-temperature working conditions in summer. The lubricating oil cooling process of the centrifugal compressor of the utility model completely controls the lubricating oil temperature of the centrifugal compressor to be within the design value range, ensuring the safe and stable operation of the centrifugal compressor.

[0025] The utility model utilizes the existing equipment conditions at the production site, makes substantial improvements to the existing equipment, achieves remarkable technical effects, and has remarkable practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of a prior art centrifugal compressor lubricating oil cooling system.

[0027] Figure 2 Schematic diagram of the lubricating oil cooling system of the centrifugal compressor of the present invention.

[0028] Figure 3 The utility model embodiment sets the 35000m 3 Schematic diagram of the lubricating oil cooling system for the centrifugal oxygen compressor of a / h air separation unit.

[0029] Figure 4 The utility model embodiment sets the 20000m nitrogen water tower 3 Schematic diagram of the lubricating oil cooling system of the centrifugal air compressor of the / h air separation unit.

[0030] Explanation of symbols in the accompanying drawings: E10, circulating cooling water cooling tower; B1, normal temperature circulating cooling water pump; V9, normal temperature cooling water manual regulating valve; V1, normal temperature cooling water regulating valve; E2, centrifugal compressor lubricating oil cooler; D1, centrifugal compressor oil pump; D2, centrifugal compressor and main motor bearings; T1, lubricating oil thermometer; E7, low-temperature cooling water production equipment; B2, low-temperature cooling water pump; V2, low-temperature cooling water regulating valve; V3, low-temperature cooling water pressure regulating valve; E11, air separation unit cooling water using equipment; E71, chiller; P1, low-temperature cooling water pressure gauge; E72, nitrogen water tower; F1, low-temperature cooling water flow meter. DETAILED DESCRIPTION

[0031] The following will be combined with the appendix of this utility model Figure 2 、 3 4. A clear and complete description of the technical solutions of the embodiments of the present utility model is provided; obviously, the embodiments described are only part of the embodiments of the present utility model, not all of them.

[0032] The embodiment of the utility model includes five aspects: lubricating oil cooling process design, calculation and selection of chiller and low-temperature cooling water pump, setting of cooling water pneumatic regulating valve and thermometer, pressure gauge and flow meter, lubricating oil temperature control logic design, and automatic operation.

[0033] Example 1, the utility model 35000m 3 / h air separation unit centrifugal oxygen compressor lubricating oil cooling process, set the chiller E71 as the low-temperature cooling water source equipment.

[0034] 35000m 3 / h air separation unit is equipped with 3 circulating cooling water cooling towers E10, and the design values ​​of circulating cooling water supply flow, pressure and temperature are 4000m 3 / h, 0.35MPa, and 28℃, respectively, are the centrifugal air compressor, nitrogen compressor, oxygen compressor, air cooling tower, and nitrogen water tower that deliver circulating cooling water.

[0035] 35000m 3 / h air separation unit is equipped with a centrifugal oxygen compressor, referred to as centrifugal oxygen compressor. The centrifugal oxygen compressor lubricating oil system includes a tubular lubricating oil cooler E2. The oxygen compressor lubricating oil cooler E2 consists of a shell and tube heat exchanger and a thermometer T1. The cooling water flow rate of the lubricating oil cooler E2 is designed to be 10m 3 / h, the design value, high alarm value and low alarm value of the lubricating oil temperature are 40℃, 50℃ and 30℃ respectively, and the diameter of the normal temperature cooling water pipeline and the valve diameter of the normal temperature cooling water regulating valve V1 of the lubricating oil cooler E2 are both 50mm.

[0036] The centrifugal oxygen compressor lubricating oil cooling system of the utility model embodiment includes a pipeline leading out from the circulating cooling water cooling tower E10, which is connected in sequence to the normal temperature circulating cooling water pump B1 and the centrifugal compressor lubricating oil cooler E2, a normal temperature cooling water regulating valve V1 is installed between the normal temperature circulating cooling water pump B1 and the centrifugal compressor lubricating oil cooler E2 for control, and a pipeline is led out from the centrifugal compressor lubricating oil cooler E2 to be connected to the circulating cooling water cooling tower E10 to form a circulating cooling water closed-loop pipeline; the technical solution of the utility model leads out a branch pipe from the normal temperature circulating cooling water pump B1 and before the normal temperature cooling water regulating valve V1, and the branch pipe is connected to the normal temperature circulating cooling water pump B1 and the centrifugal compressor lubricating oil cooler E2. The low-temperature cooling water group 71, the low-temperature cooling water pump B1, and the low-temperature cooling water regulating valve V2 are connected to the pipeline outlet after the normal-temperature cooling water regulating valve V1 and before the centrifugal compressor lubricating oil cooler E2. A pressure gauge P1 is installed after the low-temperature cooling water pump B2, that is, a two-way cooling water inlet pipeline system is formed before the lubricating oil cooler E2. One way is the normal-temperature cooling water inlet pipeline of the prior art, and the other way is the low-temperature cooling water inlet pipeline added by the present invention. The two inlet pipelines are combined before the centrifugal compressor lubricating oil cooler E2; other branches are led out from the normal-temperature circulating cooling water pump B1 to connect to other cooling water-using equipment E11 in the air separation unit.

[0037] The operating process of Example 1 of the present invention is as follows: When the lubricating oil thermometer T1 at the outlet of the oxygen compressor lubricating oil cooler E2 displays a value below the high alarm value of 50°C, the normal-temperature cooling water delivery pipeline system of lubricating oil cooler E2 is put into operation, the low-temperature cooling water delivery pipeline system is deactivated, and normal-temperature cooling water is used to cool the lubricating oil in the shell side of lubricating oil cooler E2. In the circulating cooling water cooling tower E10, the normal-temperature circulating cooling water is cooled by a fan and enters the water storage tank. It is pressurized by the normal-temperature circulating cooling water pump B1. A portion of the normal-temperature circulating cooling water is regulated by the oxygen compressor normal-temperature cooling water pneumatic regulating valve V1 and then input into the oxygen compressor lubricating oil cooler E2 pipeline, exchanging heat with the lubricating oil in the shell side of lubricating oil cooler E2, controlling the lubricating oil temperature within the designed range of 40°C.

[0038] When the lubricating oil thermometer T1 at the outlet of the oxygen compressor lubricating oil cooler E2 displays a value higher than the high alarm value of 50°C, the low-temperature cooling water delivery pipeline system is put into operation and the normal-temperature cooling water delivery pipeline system remains in operation. At this time, the cooling water of the oxygen compressor lubricating oil cooler E2 adopts a two-way water inlet process, one for normal-temperature cooling water and the other for low-temperature cooling water. Under this operating condition, the chiller E71 is started, and some normal-temperature circulating cooling water at the outlet of the normal-temperature circulating cooling water pump B1 enters the chiller E71. The refrigerant in the chiller E71 exchanges heat with the normal-temperature circulating cooling water, and the normal-temperature circulating cooling water is cooled and converted into low-temperature cooling water. This is pressurized by the low-temperature cooling water pump B2, regulated by the low-temperature cooling water pneumatic regulating valve V2, and injected into the lubricating oil cooler E2 water inlet pipe, thereby reducing the cooling water temperature input to the lubricating oil cooler E2 pipe line and rapidly reducing the lubricating oil temperature to within the design value range.

[0039] The first embodiment of the present invention retains the existing lubricating oil cooler E2 normal temperature cooling water delivery pipeline system, and improves the normal temperature cooling water regulating valve V1 to a pneumatic single-seat sleeve regulating valve. The valve diameter is the same as the normal temperature cooling water pipeline diameter of the lubricating oil cooler E2, both of which are 50mm, thereby reducing the flow resistance of the normal temperature cooling water. The chiller E71 designed in the present invention is a water-cooled screw chiller. The low temperature cooling water flow rate and temperature of the chiller E71 are designed to be 10m 3 / h, 10℃; the low-temperature cooling water pump B2 is designed to be a centrifugal water pump, and the low-temperature cooling water flow rate and pressure of the low-temperature cooling water pump B2 are designed to be 10m 3 / h, 0.4MPa, so that the low temperature cooling water flow rate and the normal temperature cooling water flow rate are 10m 3 / h is the same; at the same time, the low-temperature cooling water pressure of 0.4MPa is higher than the normal-temperature cooling water pressure of 0.35MPa, so that the low-temperature cooling water can be stably input into the lubricating oil cooler E2 inlet pipe; the designed diameter of the low-temperature cooling water pipeline is the same as the diameter of the lubricating oil cooler E2 normal-temperature cooling water pipeline, both of which are 50mm; the low-temperature cooling water pneumatic regulating valve V2 is designed to be a pneumatic multi-hole sleeve-type regulating valve, and the diameter of the low-temperature cooling water pneumatic regulating valve V2 is the same as the normal-temperature cooling water regulating valve V1, both of which are 50mm.

[0040] In the first embodiment of the present invention, the lubricating oil thermometer T1 at the outlet of the lubricating oil cooler E2 is a platinum resistance thermometer, and the pressure gauge P1 after the low-temperature cooling water pump B2 is a capacitive differential pressure transmitter; the normal temperature cooling water pneumatic regulating valve V1, the chiller E71, the low-temperature cooling water pump B2 and the pressure gauge P1, the low-temperature cooling water pneumatic regulating valve V2, the lubricating oil thermometer T1, are electrically connected to the DCS control system of the 35000m3 / h air separation unit. At the same time, an automatic control logic for the lubricating oil temperature of the oxygen compressor is added to the DCS control system of the 35000m3 / h air separation unit; in the automatic control logic for the lubricating oil temperature of the oxygen compressor, the normal temperature cooling water regulating valve V1 is set to adjust the lubricating oil temperature according to the design value of 40°C. ; Set the chiller E71 and low-temperature cooling water pump B2 to automatically start and stop according to the high alarm value of 50℃ and the low alarm value of 30℃ of the lubricating oil temperature. When the lubricating oil temperature rises to the high alarm value of 50℃, the chiller E71 automatically starts, and the low-temperature cooling water pump B2 automatically starts according to the operation signal of the chiller E71 to deliver low-temperature cooling water. When the lubricating oil temperature drops to the low alarm value of 30℃, the chiller E71 and the low-temperature cooling water pump B2 automatically stop at the same time; set the interlock control logic of the low-temperature cooling water pneumatic regulating valve V2. When the chiller E71 and the low-temperature cooling water pump B2 are in operation at the same time and the pressure gauge P1 displays a value of 0.4MPa, the low-temperature cooling water pneumatic regulating valve V2 opens.

[0041] In the automatic control logic of the lubricating oil temperature of the oxygen compressor, the lubricating oil temperature is set to be adjusted in three steps:

[0042] In the first step, when the lubricating oil temperature reaches the low alarm value, the chiller E71 and the low-temperature cooling water pump B2 are shut down, and the low-temperature cooling water pneumatic regulating valve V2 is fully closed; the normal-temperature cooling water regulating valve V1 automatically reduces the valve opening according to the lubricating oil temperature value, reduces the normal-temperature cooling water flow, and raises the lubricating oil temperature to the design value of 40°C.

[0043] In the second step, when the lubricating oil temperature is greater than the design value of 40℃ and less than the high alarm value of 50℃, the normal temperature cooling water regulating valve V1 automatically increases the valve opening according to the lubricating oil temperature value, increases the normal temperature cooling water flow, and reduces the lubricating oil temperature to the design value of 40℃.

[0044] In the third step, when the lubricating oil temperature rises to the high alarm value of 50°C, the chiller E71 and the low-temperature cooling water pump B2 automatically start, the pressure gauge P1 shows that the low-temperature cooling water pressure rises to 0.4MPa, and the low-temperature cooling water pneumatic regulating valve V2 opens and automatically increases the valve opening according to the lubricating oil temperature value, increases the low-temperature cooling water flow, and reduces the lubricating oil temperature to the design value of 40°C; when the lubricating oil temperature drops to the design value of 40°C, the low-temperature cooling water pneumatic regulating valve V2 automatically reduces the valve opening, reduces the low-temperature cooling water flow, and controls the lubricating oil temperature within the design value range of 40°C.

[0045] The automatic operation method of the centrifugal oxygen compressor lubricating oil cooling device in the first embodiment of the utility model is as follows:

[0046] The centrifugal oxygen compressor was put into operation, and the ambient temperature cooling water delivery system was simultaneously activated. The circulating cooling water cooling tower E10 and the ambient temperature circulating cooling water pump B1 were put into operation. The oxygen compressor oil pump D1 was started to cool the centrifugal oxygen compressor and the main motor bearing D2. The lubricating oil thermometer T1 automatically controlled the logic switch and automatically put the ambient temperature cooling water pneumatic control valve V1 into automatic regulation mode, keeping the lubricating oil temperature below the design value of 40°C. When the oxygen compressor was started, the lubricating oil temperature rose to the design value of 40°C, and the ambient temperature cooling water pneumatic control valve V1 automatically increased its opening to keep the lubricating oil temperature within the design value of 40°C.

[0047] The temperature of the normal temperature circulating cooling water rises, and the lubricating oil temperature of the oxygen compressor rises to the high alarm value of 50℃. The chiller E71 and the low-temperature cooling water pump B2 start automatically, and the low-temperature cooling water pneumatic regulating valve V2 is put into automatic adjustment state to control the lubricating oil temperature within the design value range of 40℃.

[0048] Shut down the centrifugal oxygen compressor, the low-temperature cooling water delivery system automatically shuts down, shut down the centrifugal oxygen compressor oil pump D1, the normal-temperature cooling water delivery system automatically shuts down, and the lubricating oil temperature automatic control logic switch automatically turns off.

[0049] Example 2: The utility model sets up a 20000m3 nitrogen water tower E72. 3 / h air separation unit centrifugal air compressor lubricating oil cooling process and equipment.

[0050] The utility model embodiment 20000m 3 / h air separation unit is equipped with a centrifugal air compressor (abbreviated as: air compressor), and the air compressor is equipped with a tubular lubricating oil cooler E2. The cooling water flow rate of the lubricating oil cooler E2 is designed to be 6m 3 / h, the design value, high alarm value and low alarm value of the lubricating oil temperature are 38℃, 50℃ and 30℃ respectively. The original design diameter of the normal temperature cooling water pipe of the lubricating oil cooler E2 and the valve diameter of the normal temperature cooling water manual regulating valve V1 are both 40mm.

[0051] The utility model embodiment 20000m 3 / h air separation unit is equipped with a circulating cooling water system, equipped with two circulating cooling water cooling towers E10, the circulating cooling water supply flow, pressure and temperature are designed to be 2600m 3 / h, 0.4MPa, 28℃, respectively, are used to supply circulating cooling water to the centrifugal air compressor, air booster, nitrogen compressor intermediate gas cooler, lubricating oil cooler E2 and air cooling tower, and nitrogen water tower E72.

[0052] The air compressor lubricating oil cooling process of the utility model embodiment is composed of a normal temperature cooling water delivery pipeline system, a low temperature cooling water delivery pipeline system, and a lubricating oil cooler E2; the normal temperature cooling water delivery pipeline system is composed of a circulating cooling water cooling tower E10, a normal temperature circulating cooling water pump B1, a normal temperature cooling water pneumatic regulating valve V1 and a normal temperature cooling water pipeline connected in sequence; the low temperature cooling water delivery pipeline system is composed of a nitrogen water tower E72, a low temperature cooling water pump B2, a flow meter F1, a pressure regulating valve V3, a pressure gauge P1, a low temperature cooling water pneumatic regulating valve V2 and a low temperature cooling water pipeline connected in sequence, and the two cooling water pipelines are combined in the pipeline before the inlet of the lubricating oil cooler E2; after the normal temperature circulating cooling water pump B1, The pipeline is divided into two routes. One route connects to the nitrogen water tower E72, and the other route is connected to the inlet pipe of the lubricating oil cooler E2 through the normal temperature cooling water pneumatic regulating valve V1. The pipeline connecting to the nitrogen water tower E72 is connected to the low-temperature cooling water pump B2 on the outlet pipe of the nitrogen water tower E72 and is installed with a flow meter F1. The outlet of the low-temperature cooling water pump B2 is connected to the low-temperature cooling water user E11. A branch pipe is led out from the low-temperature cooling water pipeline after the outlet of the low-temperature cooling water pump B2. The branch pipe is connected to the low-temperature cooling water pressure regulating valve V3 and the low-temperature cooling water pneumatic regulating valve V2 in sequence. After the low-temperature cooling water pneumatic regulating valve V2, it is connected to the inlet pipe of the lubricating oil cooler E2. At the same time, a pressure gauge P1 is installed after the low-temperature cooling water pressure regulating valve V3.

[0053] In nitrogen water tower E72, 20000m 3 / hThe low-temperature contaminated nitrogen gas extracted from the upper tower of the air separation unit exchanges heat with the normal-temperature circulating cooling water at the outlet of the normal-temperature circulating cooling water pump B1. The cooling water releases heat and the contaminated nitrogen gas absorbs heat. At the same time, part of the cooling water evaporates and releases latent heat of vaporization. The normal-temperature cooling water is cooled to low-temperature cooling water at 12°C. The low-temperature cooling water is pressurized by the low-temperature cooling water pump B2. Part of it is transported to the top of the air cooling tower of the low-temperature cooling water-using equipment to cool the processed air at the outlet of the air compressor; the other part is transported to the air compressor lubricating oil cooler E2 to cool the lubricating oil of the bearings of the air compressor and the main motor D2.

[0054] In this embodiment of the utility model, 20000m 3 / h air separation unit nitrogen water tower E72, low temperature cooling water pump B2, air cooling tower original design low temperature cooling water flow rate is 80m 3 / h、60m 3 / h、45m 3 / h, the original design outlet low-temperature cooling water pressure of low-temperature cooling water pump B2 is 0.95MPa, and the design redundancy of nitrogen water tower E72 and low-temperature cooling water pump B2 is large. By utilizing the design redundancy of nitrogen water tower E72 and low-temperature cooling water pump B2, a small amount of low-temperature cooling water at the outlet of low-temperature cooling water pump B2 is input into the water inlet pipe of air compressor lubricating oil cooler E2, thereby reducing the cooling water temperature of lubricating oil cooler E2 pipe side and controlling the lubricating oil temperature within the design value range.

[0055] In this embodiment, the low-temperature cooling water flow rate of the lubricating oil cooler E2 is designed to be 6m 3 / h, and the normal temperature cooling water flow rate is 6m 3 / h is the same, and the designed low-temperature cooling water pressure is 0.45MPa, which is 0.4MPa higher than the normal-temperature cooling water pressure, so that the low-temperature cooling water can be stably input into the normal-temperature cooling water pipeline at the water inlet end of the lubricating oil cooler E2, and the low-temperature cooling water temperature at the outlet of the low-temperature cooling water pump B2 is 12℃.

[0056] When the lubricating oil temperature at the outlet of the air compressor lubricating oil cooler E2 is lower than the design value of 38°C, the lubricating oil cooler E2 uses normal temperature cooling water to cool the lubricating oil in the shell side of the lubricating oil cooler E2. That is, in the circulating cooling water cooling tower E10, the normal temperature circulating cooling water is cooled by the fan and enters the water storage tank. It is pressurized by the normal temperature circulating cooling water pump B2. Part of the normal temperature circulating cooling water is regulated by the air compressor normal temperature cooling water pneumatic regulating valve V1 and input into the air compressor lubricating oil cooler E2 pipe side to exchange heat with the lubricating oil in the shell side of the lubricating oil cooler E2, so as to control the lubricating oil temperature to be within the design value range of 38°C.

[0057] In the above-mentioned pipeline of this embodiment, the low-temperature cooling water pneumatic regulating valve V2 is designed as a pneumatic diaphragm single-seat sleeve regulating valve with high flow regulation sensitivity, and the low-temperature cooling water pressure regulating valve V3 is designed as a bellows-balanced self-supporting pressure regulating valve with precise pressure regulation. The low-temperature cooling water pressure at the outlet of the low-temperature cooling water pump B2 is reduced from 0.95 MPa to the design value of 0.45 MPa through the pressure regulating valve V3; the valve diameter of the low-temperature cooling water pneumatic diaphragm single-seat sleeve regulating valve V2 and the low-temperature cooling water pipeline diameter are the same as the diameter of the normal-temperature cooling water pipeline of the lubricating oil cooler E2, both of which are 40 mm.

[0058] In this embodiment, the lubricating oil thermometer T21, flowmeter F1, and pressure gauge P2 are designed to be a platinum resistance thermometer, an electromagnetic flowmeter, and a capacitive differential pressure transmitter, respectively. The ambient temperature cooling water regulating valve V1, nitrogen water tower E72, low-temperature cooling water pump B2, low-temperature cooling water pneumatic regulating valve V2, flowmeter F1, pressure gauge P2, and lubricating oil thermometer T1 are electrically connected to the DCS control system of the 20,000 m³ / h air separation unit. Automatic air compressor lubricating oil temperature control logic is added to the DCS control system of the 20,000 m³ / h air separation unit. Both the ambient temperature cooling water regulating valve V1 and the low-temperature cooling water pneumatic regulating valve V2 automatically adjust their valve openings based on the lubricating oil temperature design value of 38°C.

[0059] When the lubricating oil temperature is no higher than the design value of 38°C, the low-temperature cooling water pneumatic regulating valve V2 automatically closes fully, and the normal-temperature cooling water regulating valve V1 automatically adjusts its valve opening to raise the lubricating oil temperature to the design value of 38°C. The interlocking control logic of the low-temperature cooling water pneumatic regulating valve V2 is designed so that the low-temperature cooling water pneumatic regulating valve V2 will not automatically open until the low-temperature cooling water flow rate at the outlet of the low-temperature cooling water pump B2 is adjusted to 60m3 / h and the low-temperature cooling water pressure at the outlet of the pressure regulating valve V3 is adjusted to 0.45MPa. This ensures that the low-temperature cooling water inlet flow rate of the air cooling tower of production equipment E11 is no less than the design value and the low-temperature cooling water input to the lubricating oil cooler E2 is stable. When the outlet thermometer T1 of the air compressor lubricating oil cooler E2 indicates that the lubricating oil temperature rises above the design value of 38°C, the low-temperature cooling water pneumatic regulating valve V2 opens, injecting some of the low-temperature cooling water at the outlet of the low-temperature cooling water pump B2 into the lubricating oil cooler E2 inlet pipe, reducing the lubricating oil temperature to the design value range of 38°C.

[0060] The automatic operation steps of the air compressor lubricating oil cooling device of the utility model embodiment are as follows:

[0061] 1. Put the circulating cooling water cooling tower E10, normal temperature circulating cooling water pump B1, nitrogen water tower E72, and low temperature cooling water pump B2 into operation. Start the air compressor oil pump E2. The lubricating oil temperature automatic control logic switch is automatically put into operation. The normal temperature cooling water pneumatic regulating valve V1 is put into automatic adjustment state to control the lubricating oil temperature to be no higher than the design value of 38°C.

[0062] 2. Start the air compressor. When the outlet thermometer T1 of the air compressor lubricating oil cooler E2 shows that the lubricating oil temperature rises to greater than the design value of 38°C, the low-temperature cooling water flowmeter F1 at the outlet of the low-temperature cooling water pump B2 shows that the flow rate reaches 60m3 / h, and the low-temperature cooling water pressure gauge at the outlet of the low-temperature cooling water regulating valve V3 shows a value of 0.45MPa, the low-temperature cooling water pneumatic regulating valve V2 automatically opens, and part of the low-temperature cooling water at the outlet of the low-temperature cooling water pump B2 is injected into the water inlet pipe of the lubricating oil cooler E2 to reduce the lubricating oil temperature to the design value range of 38°C. When the value displayed on the thermometer T1 reaches 38°C, the low-temperature cooling water pneumatic regulating valve V2 automatically closes, and the normal temperature cooling water pneumatic regulating valve V1 automatically adjusts the opening to maintain the lubricating oil temperature within the design value range of 38°C.

[0063] 3. The air compressor stops operating, the nitrogen water tower E72 and the low-temperature cooling water pump B2 automatically stop operating, the low-temperature cooling water pneumatic regulating valve V2 automatically closes, the air compressor oil pump D1 stops operating, the normal temperature cooling water pneumatic regulating valve V1 automatically closes, and the lubricating oil temperature automatic control logic switch automatically closes.

Claims

1. A centrifugal compressor lubricating oil cooling system, comprising a normal temperature cooling water inlet piping system, the normal temperature cooling water inlet piping system comprising a pipeline leading from a circulating cooling water cooling tower, the pipeline sequentially connecting a normal temperature circulating cooling water pump and a centrifugal compressor lubricating oil cooler, a normal temperature cooling water regulating valve being installed between the normal temperature circulating cooling water pump and the centrifugal compressor lubricating oil cooler for control, characterized in that: Another low-temperature cooling water inlet pipeline system is added, including a branch pipe led out after the normal temperature circulating cooling water pump and before the cooling water regulating valve, the branch pipe is connected to the low-temperature cooling water production equipment, the low-temperature cooling water pump, and the low-temperature cooling water regulating valve in sequence, and the pipeline outlet is connected to the normal temperature cooling water regulating valve and before the centrifugal compressor lubricating oil cooler; that is, a two-way cooling water inlet pipeline system is formed in front of the lubricating oil cooler, one is the normal temperature cooling water inlet pipeline of the existing technology, and the other is the added low-temperature cooling water inlet pipeline, the low-temperature cooling water inlet pipeline is connected to the normal temperature cooling water inlet pipeline, the two inlet pipelines are combined into one inlet pipeline connected to the inlet of the centrifugal compressor lubricating oil cooler, and an outlet pipe is led out from after the centrifugal compressor lubricating oil cooler and connected to the circulating cooling water cooling tower to form a circulating cooling water closed-loop pipeline.

2. A centrifugal compressor lubricating oil cooling system according to claim 1, characterized in that: The low-temperature cooling water production equipment is a chiller, which transports part of the normal-temperature cooling water in the pipeline after the normal-temperature circulating cooling water pump of the circulating cooling water system to the chiller through the branch pipeline to cool it into low-temperature cooling water, and inputs it into the low-temperature cooling water inlet pipeline.

3. The centrifugal compressor lubricating oil cooling system according to claim 1, characterized in that: The low-temperature cooling water production equipment is a refrigeration equipment of a production line to which a centrifugal compressor belongs. A small amount of low-temperature cooling water is extracted from the redundant amount of the refrigeration equipment and input into the low-temperature cooling water inlet pipe.

4. The centrifugal compressor lubricating oil cooling system according to claim 1, characterized in that: The normal temperature cooling water regulating valve and the low temperature cooling water regulating valve are both pneumatic sleeve type regulating valves.

5. A centrifugal compressor lubricating oil cooling system according to claim 4, characterized in that: The normal temperature cooling water regulating valve, low temperature cooling water regulating valve and the lubricating oil thermometer at the shell outlet of the lubricating oil cooler are electrically connected to the DCS and PLC automatic control system of the centrifugal compressor or the production line to which it belongs. According to the lubricating oil temperature set value, the pneumatic normal temperature cooling water regulating valve and the pneumatic low temperature cooling water regulating valve automatically control the valve opening to adjust the flow rate of normal temperature cooling water and low temperature cooling water input into the lubricating oil cooler.

6. The centrifugal compressor lubricating oil cooling system according to claim 1, characterized in that: The diameter of the low-temperature cooling water pipeline is the same as that of the normal-temperature cooling water pipeline, and the low-temperature cooling water pipeline is made of stainless steel.

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