Water cooler carbon dioxide stripping device and method

Abstract

The present invention discloses a water cooler carbon dioxide stripping device and method, and relates to the technical field of water cooler cleaning. A water cooler carbon dioxide stripping device comprises a carbon dioxide storage tank and a water cooler, wherein the carbon dioxide storage tank is connected to the water cooler through a pipeline provided with a control component and an injection component, wherein the control component comprises a pre-valve pressure gauge, a pre-valve temperature gauge, an inlet cut-off valve, a post-valve self-adjusting valve, an outlet cut-off valve, a post-valve temperature gauge, a post-valve pressure gauge, and a flow meter connected in sequence, and the inlet cut-off valve is connected to the outlet cut-off valve through a bypass provided with a bypass valve and a pressure relief valve; the injection component comprises a stop valve, a check valve, and a carbon dioxide extension pipe. The present invention can complete the cleaning and stripping of the water cooler in the production system without shutting down the production system, thereby solving the technical defects of the traditional cleaning and stripping method that the water cooler cleaning and stripping must be shut down and isolated, the cleaning process causes great damage to the equipment, and the long time has great safety risks.

Description

Technical Field

[0001] The invention relates to the technical field of water cooler cleaning, and in particular to a device and method for stripping carbon dioxide from a water cooler. Background Art

[0002] Water coolers are important devices for achieving heat transfer in petroleum and chemical systems. However, they are affected by the deposition of biological sludge in the water treatment system, which not only leads to a gradual decrease in heat exchange efficiency and affects the normal progress of production activities, but in severe cases, scaling on the heat exchange surface of the equipment leads to under-scale corrosion, threatening equipment safety.

[0003] At present, the methods used for cleaning water coolers in petroleum and chemical industries mainly include online system stripping, chemical cleaning of isolated equipment and high-pressure jet cleaning due to differences in cleaning targets. Among them, online system stripping is a system cleaning performed with the assistance of chemical agents. The implementation time of this process is relatively long, and the stripping effect varies greatly due to differences in the system; both chemical cleaning and high-pressure jet cleaning require the equipment to be isolated and treated separately, and the treatment effect is better, but it requires shutdown and production, and cannot be implemented online.

[0004] In order to realize the online, rapid and efficient cleaning of water coolers by stripping carbon dioxide from the water cooler separately online, a water cooler carbon dioxide stripping device was developed. Summary of the invention

[0005] The object of the present invention is to provide a water cooler carbon dioxide stripping device.

[0006] Another object of the present invention is to provide a method for stripping carbon dioxide from a water cooler.

[0007] The present invention is achieved through the following technical solutions:

[0008] A water cooler carbon dioxide stripping device comprises a carbon dioxide storage tank and a water cooler, wherein the carbon dioxide storage tank is connected to the water cooler via a pipeline provided with a control component and an injection component, wherein the control component comprises a pre-valve pressure gauge, a pre-valve temperature gauge, an inlet shut-off valve, a post-valve self-adjusting valve, an outlet shut-off valve, a post-valve temperature gauge, a post-valve pressure gauge, and a flow meter connected in sequence, wherein the inlet shut-off valve is connected to the outlet shut-off valve via a bypass provided with a bypass valve and a pressure relief valve; and the injection component comprises a stop valve, a check valve, and a carbon dioxide extension pipe.

[0009] Furthermore, the front and rear ends of the control component are respectively provided with metal hose interfaces.

[0010] One end of the stop valve of the injection assembly is connected to the control assembly through a stainless steel hose.

[0011] The check valve end of the injection assembly is connected to the inlet cooling water pipeline of the water cooler.

[0012] Furthermore, a method for stripping carbon dioxide from a water cooler using the above device comprises the following steps:

[0013] The gas phase of the carbon dioxide storage tank is connected to the pipeline equipped with control components and injection components and the water cooler. The outlet pressure of the control system's self-operated regulating valve is adjusted to ≧ the cooling water inlet pressure of the water cooler 0.4MPa, the temperature is -50~50℃, and the pressure range is 0~4MPa.

[0014] The diameter of the pipeline is DN40-50DN, and the pressure bearing capacity is not less than PN4MPa.

[0015] The pipeline connecting pipe is required to be no longer than 200 mm and have a diameter no less than 50 mm.

[0016] The present invention utilizes the properties of carbon dioxide to change the fluid flow state of cooling water in a water cooler to achieve the purpose of cleaning and stripping the heat exchanger, that is, through the difference in solubility of carbon dioxide in water and the relationship between temperature, the purpose of creating a cross flow of carbon dioxide on the heat exchange surface of the water cooler heat exchanger is achieved, causing turbulence in the cooling water passing through the heat exchange surface.

[0017] According to the law that the solubility of gaseous carbon dioxide in water changes with temperature and pressure, the carbon dioxide dissolved in the cooling water is caused to form a continuous cross flow perpendicular to the heat exchange surface under the action of the temperature gradient of the water cooler heat exchange surface, so that the cooling water in the water cooler will be turbulent to a large extent, and the deposited biological sludge will be stirred into the water flow and taken out, so as to achieve the purpose of cleaning the heat exchange surface of the water cooler.

[0018] In order to ensure the continuity and intensity of the turbulence of the cooling water flow in the water cooler, the amount of carbon dioxide added to the water flow should ensure that it is in a saturated state under this condition. The theoretical amount can be calculated based on Henry's law: Pg = HX

[0019] Where, Pg: partial pressure of carbon dioxide on the cooling water surface, H: Henry's coefficient under the conditions of carbon dioxide addition, X: molar fraction of carbon dioxide in cooling water.

[0020] The Henry coefficient is based on the Henry coefficient of carbon dioxide at different temperatures shown in Table 1, or Figure 4 The solubility diagram of carbon dioxide in water is shown.

[0021] Table 1 Henry coefficients of CO2 at different temperatures

[0022] Temperature ℃ 0 5 10 15 20 25 30 35 40 45 50 60 <![CDATA[Ex10 5 (kpa)]]> 0738 0.888 1.05 1.24 1.44 1.66 1.88 2.12 2.36 2.6 2.87 3.46

[0023] That is, the present invention controls the liquid carbon dioxide from the liquid carbon dioxide storage tank through the control component and then passes through the injection component and enters the system through the cooling water inlet pipe of the water cooler. In order to prevent the cooling water from seeping into the carbon dioxide pipeline during the stripping process and causing the pipeline to freeze, the carbon dioxide cannot enter the system at the bottom of the cooling water pipeline. The post-valve self-operated regulating valve of the control component is designed to stabilize the carbon dioxide injection pressure. The temperature, pressure and flow meters are set to monitor the operation of the control system. In order to prevent the failure of the self-operated regulating valve from affecting the operation of the system, a passage cut-off valve and a bypass valve are arranged before and after the self-operated regulating valve. When the self-operated pressure regulating valve fails, the bypass valve can be used instead. One end of the injection component is connected to the control component through a stainless steel hose, and the other end is connected to the cooling water pipeline at the inlet of the water cooler. The valve group consists of a check valve and a stop valve. The stop valve is used to control the stripping carbon dioxide flow rate. The injection carbon dioxide flow rate is 0.4% to 0.7% of the total cooling water passing through the water cooler. The check valve prevents cooling water from flowing back into the carbon dioxide system to freeze and block the pipeline. The function of the extension pipe is to directly deliver liquid carbon dioxide into the main cooling water fluid to prevent liquid carbon dioxide from forming a low-temperature zone locally and causing cooling water to freeze. The length is determined according to the actual situation on site.

[0024] When the system is running, the amount of carbon dioxide injected is calculated based on the amount of cooling water used in the equipment. To ensure the accuracy of the carbon dioxide injection, the cooling water exhaust valve at the water cooler outlet should be opened during the operation of the stripping system. There should be obvious continuous overflow or spraying of carbon dioxide bubbles in the exhaust water. The control system runs for 1 to 3 hours. To obtain the best effect of sludge stripping, short-term air resistance can be artificially created when conditions permit to obtain the maximum temperature difference between the inlet and outlet of the water cooler to increase the power during the stripping process.

[0025] Compared with the prior art, the present invention can complete the cleaning and stripping of the water cooler in the production system without shutting down the production system, solving the technical defects of the traditional cleaning and stripping method that the water cooler cleaning and stripping must be shut down and isolated, the cleaning process causes great damage to the equipment, and the cleaning time is long and the safety risks are high. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the structure of the present invention;

[0027] Figure 2 It is a schematic diagram of the control component structure;

[0028] Figure 3 This is a schematic diagram of the injection component structure;

[0029] Figure 4 This is a graph showing the solubility of carbon dioxide in water.

[0030] In the figure: 1-carbon dioxide storage tank, 2-control component, 3-injection component, 4-water cooler, 5-pressure gauge before valve, 6-temperature gauge before valve, 7-inlet cut-off valve, 8-self-operated regulating valve after valve, 9-outlet cut-off valve, 10-temperature gauge after valve, 11-pressure gauge after valve, 12-flow meter, 13-bypass valve, 14-pressure relief valve, 15-stop valve, 16-check valve. DETAILED DESCRIPTION

[0031] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0032] Example 1

[0033] like Figure 1 The water-cooled carbon dioxide stripping device shown in the figure comprises a carbon dioxide storage tank 1 and a water cooler 4, wherein the carbon dioxide storage tank 1 is connected to the water cooler 4 via a pipeline provided with a control component and an injection component, wherein the control component structure is as follows Figure 2 As shown, it includes a pre-valve pressure gauge 5, a pre-valve temperature gauge 6, an inlet shut-off valve 7, a post-valve self-adjusting valve 8, an outlet shut-off valve 9, a post-valve temperature gauge 10, a post-valve pressure gauge 11, and a flow meter 12 which are connected in sequence, wherein the inlet shut-off valve 9 is connected to the outlet shut-off valve 9 via a bypass provided with a bypass valve 13 and a pressure relief valve 14; the injection assembly includes a stop valve 15, a check valve 16, and a carbon dioxide extension pipe.

[0034] The control component is provided with metal hose interfaces at both ends, one end is connected to the carbon dioxide storage tank 1 through a joint, and the other end is connected to a stainless steel hose provided at one end of the injection component, and the other end of the injection component is connected to the inlet cooling water pipeline of the water cooler.

[0035] During operation, the liquid carbon dioxide from the liquid carbon dioxide storage tank is controlled by the control component and then passes through the injection component and the cooling water inlet pipe of the water cooler into the system. To prevent cooling water from seeping into the carbon dioxide pipeline during the stripping process and causing the pipeline to freeze, carbon dioxide cannot enter the system at the bottom of the cooling water pipeline.

[0036] When the cooling water inlet temperature of the cooler is 30℃, the Henry coefficient of carbon dioxide is 1.88×10 5 mol / l, the initial saturated vapor pressure of cooling water is 100 kPa (absolute), the maximum vapor pressure that can be formed by carbon dioxide injection is 400 kPa, and the saturated concentration of CO2 in the solution = 400 / 1.88×10 5 =212.77×10 -5 mol / mol, CO2 mass in cooling water:

[0037] X CO2 =N CO2 / N CO2+N H2O N CO2 =X CO2 N H2O / (1-X CO2 )

[0038] N CO2 =212.77×10 -5 ×100 / 18 / (1-212.77×10 -5 )=11.82×10 -3

[0039] Q=44×N CO2 =44×11.82×10 -3 =0.52t / h

[0040] X CO2 -Molar CO2 fraction in cooling water N CO2 - Number of moles of CO2 in cooling water N H2O - Number of moles of H2O in cooling water

[0041] The stripping time is 2h and the CO2 injection volume is 1.04t

[0042] When running, the steps are:

[0043] (1) System Preparation

[0044] Close all process valves of the injection system, open the root valve of the instrument, open the gas phase valve of the CO2 storage tank and the carbon dioxide injection control component, pressurize the system to 1MPa, stop the pressure for 5 minutes to check the system, and after confirming that there are no leaks in the system, continue to pressurize until the system and vehicle pressures are balanced, close the gas phase valve of the CO2 tanker, stop the pressure for 30 minutes to check the system pipelines and fittings, and the airtightness test is completed after checking and confirming that there are no external leaks in the system;

[0045] (2) CO2 stripping operation

[0046] ①Open the liquid phase valve of the CO2 storage tank, and slowly open the stop valve of the CO2 injection component. Pay attention to keeping the pressure difference between the CO2 system and the cooling water system not less than 0.4 MPa by controlling the opening of the stop valve of the component and the injection component;

[0047] ②Open the exhaust valve at the cooling water outlet of the water cooler and observe the changes in the exhaust conditions in the water of the exhaust valve;

[0048] ③ Adjust the control components to control the CO2 injection rate to about 0.52t / h. Note that there should be obvious gas overflow from the exhaust pipe at the outlet of the water cooler to keep the cross flow generated by the CO2 overflow on the heat exchange surface continuous and stable;

[0049] ④ Maintain system operation and pay attention to changes in the cooling effect of the water cooler, control the temperature of the water cooler material to rise slowly, and note that the temperature change range of the material should be within the process requirements;

[0050] ⑤ In the later stage of water cooler stripping, the CO2 injection amount can be appropriately increased under permitted conditions to create a short-term gas resistance phenomenon in the water cooler to increase the temperature gradient of the heat exchange surface and increase the turbulence amplitude and frequency of the water flow in the heat exchanger;

[0051] ⑥ After the stripping time is 2 hours, close the liquid phase valve of the CO2 tanker. When the pressure difference between the CO2 system and the cooling water system is less than 0.2 MPa, close the stop valve of the CO2 injection component and close the exhaust valve;

[0052] ⑦ Observe the change of heat exchange efficiency of the water cooler 30 minutes after the stripping is completed. If the effect does not meet the requirements, a second stripping can be performed. After the stripping is completed, remove the stripping facilities and restore the system to its original state.

[0053] (3) Operation and maintenance

[0054] ① To ensure that the CO2 stripping work of the water cooler is carried out continuously and uninterruptedly, the operator should pay attention to the liquid level of the CO2 tank truck and ensure that the vehicle has sufficient liquid.

[0055] ② Check the exhaust condition of the water cooler every 10 minutes and make timely adjustments if any abnormality is found.

[0056] ③Every 20 minutes, check the cooling water and CO2 flow, pressure, and temperature of the stripping system and keep records.

[0057] ④ Check the carbon dioxide delivery pipeline once every hour and keep records.

[0058] ⑤ If any abnormal phenomenon such as leakage or rupture of the infusion pipeline is found during inspection, immediately close the liquid phase valve of the carbon dioxide tank vehicle and the stop valve of the injection component to stop supplying liquid to the system.

[0059] ⑥ Open the liquid phase pressure relief valve of the carbon dioxide tank truck to reduce the system pressure to normal pressure, and put the system back into operation after it passes the treatment.

[0060] (4) System shutdown

[0061] ① Close the liquid phase valve of the carbon dioxide tank truck. After the pressure difference between the CO2 system and the cooling water system is less than 0.2 MPa, close the stop valve of the CO2 injection component and close the exhaust valve.

[0062] ② Open the liquid phase pressure relief valve of the carbon dioxide tank truck to relieve the pressure on the connecting pipe and remove the liquid connection interface of the tank truck.

[0063] ③Remove the CO2 injection components and restore the cooling water system to its original state.

[0064] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A water cooler carbon dioxide stripping device, characterized in that: It includes a carbon dioxide storage tank and a water cooler, wherein the carbon dioxide storage tank is connected to the water cooler through a pipeline provided with a control component and an injection component, wherein the control component includes a valve front pressure gauge, a valve front temperature gauge, an inlet cut-off valve, a valve rear self-adjusting valve, an outlet cut-off valve, a valve rear temperature gauge, a valve rear pressure gauge, and a flow meter which are connected in sequence, wherein the inlet cut-off valve is connected to the outlet cut-off valve through a bypass provided with a bypass valve and a pressure relief valve; the injection component includes a stop valve, a check valve, and a carbon dioxide extension pipe, wherein one end of the stop valve is connected to the control component through a stainless steel hose, and the check valve end is butt-jointed with the inlet cooling water pipeline of the water cooler.

2. The water cooler carbon dioxide stripping device according to claim 1, characterized in that: The front and rear ends of the control component are respectively provided with metal hose interfaces.

3. A method for stripping carbon dioxide from a water cooler using the device according to claim 1 or 2, characterized in that: The steps are: connect the gas phase of the carbon dioxide storage tank to the pipeline equipped with control components and injection components and the water cooler, adjust the outlet pressure of the control system's self-operated regulating valve to ≧ the cooling water inlet pressure of the water cooler 0.4MPa, the temperature is -50~50℃, and the pressure range is 0~4MPa.

4. The method for stripping carbon dioxide from a water cooler according to claim 3, characterized in that: The diameter of the pipeline is DN40-50DN, and the pressure bearing capacity is not less than PN4MPa.

5. The method for stripping carbon dioxide from a water cooler according to claim 3, characterized in that: The pipeline connecting pipe is required to be no longer than 200 mm and have a diameter no less than 50 mm.

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