CN-122015356-A - Solid dry ice removing method

CN122015356ACN 122015356 ACN122015356 ACN 122015356ACN-122015356-A

Abstract

The invention discloses a solid dry ice removing method in the technical field of carbon dioxide refrigeration, which comprises the following steps of obtaining flow, pressure and temperature data of a refrigeration system and a filling pipeline thereof, judging whether the refrigeration system and the filling pipeline thereof are blocked or not based on the data, sequentially closing pipe sections in a segmented mode during blocking, judging that one pipe section is a blocked pipe section if the change amplitude of the upstream and downstream pressure change rate of the pipe section is lower than a set value, removing dry ice through heat tracing and gas purging, and purging gaseous carbon dioxide downstream of the blocked pipe section in the gas purging process to purge the dry ice along the reverse direction of the blocking direction. According to the invention, the blockage is judged by comprehensively monitoring the changes of flow, pressure, temperature and the like, and the dry ice blockage is accurately positioned by adopting a mode of closing the pipeline in a sectionalized manner, so that the blocked pipe section is quickly locked, an accurate target is provided for efficient removal of dry ice, and the phenomena of local pipeline overheating and pressure runaway caused by dry ice removal are avoided.

Inventors

Zhan deqing
PAN XINYU
WANG LI
XU XIANG
ZHONG KAI
Zhang Aosen

Assignees

中国化学工程第三建设有限公司

Dates

Publication Date: 20260512
Application Date: 20251231

Claims (10)

1. A method for removing dry ice in a refrigeration system and a filling line thereof, the refrigeration system and the filling line thereof being divided into a plurality of pipe sections, comprising the steps of: Acquiring flow, pressure and temperature data of the refrigeration system and a filling pipeline thereof, and judging whether the refrigeration system and the filling pipeline thereof are blocked or not based on the change of the flow, pressure and temperature data; When the refrigerating system and the filling pipeline thereof are blocked, sequentially closing each pipe section in a segmented manner, and judging that the pipe section is a blocked pipe section if the variation amplitude of the upstream and downstream pressure variation rate of one pipe section is lower than a set value after the segmented closing of the other pipe section; and removing the dry ice in the refrigerating system and the filling pipeline thereof through heat tracing and/or gas purging so as to dredge the blocked pipe section.
2. The method for removing solid dry ice as claimed in claim 1, wherein the dry ice in the blocked pipe section is removed by the heat tracing device during the heat tracing process, and the gaseous carbon dioxide is purged downstream of the blocked pipe section during the gas purging process, so that the gaseous carbon dioxide purges the dry ice in the direction opposite to the blocking direction.
3. A solid dry ice removal method as set forth in claim 1, wherein the presence of a clog is determined when the ratio of the real-time flow rate to the set flow rate is continuously lower than a first set value or the real-time flow rate is zero during a first set time, the presence of a clog is determined when the upstream pressure change rate is continuously higher than a second set value during a second set time, and the presence of a clog is determined when the ratio of the real-time temperature to the set temperature is continuously lower than a third set value during a third set time.
4. The method for removing solid dry ice as claimed in claim 1, wherein the filling pipeline is provided with a liquid storage tank and a heat exchanger, the liquid storage tank is filled with carbon dioxide into the refrigerating system through the heat exchanger, a low-temperature liquid pump is arranged between the liquid storage tank and the heat exchanger, and when the low-temperature liquid pump alarms abnormally, the liquid storage tank or the pipeline between the liquid storage tank and the low-temperature liquid pump is judged to be blocked.
5. A method of removing solid dry ice as claimed in claim 4, wherein when there is a blockage in the refrigeration system and its filler pipe, the filling rate of the filler pipe is reduced or the liquid storage tank is stopped from discharging before the pipe sections are sequentially closed in sections.
6. A method for removing solid dry ice as claimed in claim 4, wherein the gaseous carbon dioxide source is a liquid storage tank or an external gas source when the gaseous carbon dioxide is purged downstream of the blocked pipe section.
7. A method of removing solid dry ice as claimed in claim 6, wherein the gas source is a liquid storage tank, and the pressure of the liquid storage tank is higher than a set pressure.
8. A method of removing solid dry ice as claimed in claim 7, wherein the top of the tank is provided with an exhaust pipe, the exhaust pipe is communicated with a plurality of pipe sections, an air bag is arranged in the tank and is used for providing power for purging gaseous carbon dioxide and maintaining the pressure in the tank.
9. A method for removing solid dry ice as claimed in claim 8, wherein the gas in the air bag and the carbon dioxide in the liquid storage tank are isolated from each other.
10. The method for removing solid dry ice as claimed in claim 1, wherein the heat-tracing process comprises removing the heat-insulating layer on the blocked pipe section, and sleeving a heat-tracing device on the blocked pipe section, wherein the heat-tracing device is electric tracing or steam tracing.

Description

Solid dry ice removing method Technical Field The invention relates to the field of carbon dioxide refrigeration, in particular to a solid dry ice removing method. Background Dry ice blockage is a common and troublesome problem in industrial systems that utilize liquid carbon dioxide for refrigeration, such as coal mine downhole refrigeration systems that include a carbon dioxide compressor, a throttling device, and a heating and cooling device. When the pressure in the pipeline or the container is too low, the liquid carbon dioxide can be gasified and absorb heat rapidly, so that the local temperature is suddenly reduced to be below the freezing point, solid dry ice is formed, and the refrigerating system and the filling pipeline thereof are blocked. The traditional dry ice blockage treatment method is passive, and usually adopts a mode of suspending operation, naturally heating or simply baking after abnormal flow or equipment alarm is found. These methods are inefficient, have long thawing times, and severely affect production continuity. More seriously, the traditional method lacks a rapid and accurate positioning technology for the blocking position, and the blocking cannot be removed by blind treatment, and even local overheating or out-of-control pressure caused by improper operation causes new safety risks. Thus, there is a need for a method that can quickly respond, accurately locate, and safely and efficiently remove dry ice blockage. Disclosure of Invention The invention aims to provide a solid dry ice removing method which solves the problems that the existing refrigerating system and filling pipeline dry ice are difficult to block and position and the pipeline dredging efficiency is insufficient. The invention realizes the above purpose through the following technical scheme: A method for removing solid dry ice for removing dry ice from a refrigeration system and its filling line, the refrigeration system and its filling line being divided into a plurality of pipe sections, comprising the steps of: Acquiring flow, pressure and temperature data of the refrigeration system and a filling pipeline thereof, and judging whether the refrigeration system and the filling pipeline thereof are blocked or not based on the change of the flow, pressure and temperature data; When the refrigerating system and the filling pipeline thereof are blocked, sequentially closing each pipe section in a segmented manner, and judging that the pipe section is a blocked pipe section if the variation amplitude of the upstream and downstream pressure variation rate of one pipe section is lower than a set value after the segmented closing of the other pipe section; and removing the dry ice in the refrigerating system and the filling pipeline thereof through heat tracing and/or gas purging so as to dredge the blocked pipe section. According to the further optimization scheme, dry ice in the blocked pipe section is removed through the heat tracing device in the heat tracing process, and gaseous carbon dioxide is purged at the downstream of the blocked pipe section in the gas purging process, so that the gaseous carbon dioxide purges the dry ice along the direction opposite to the blocking direction. In a further optimized scheme of the invention, in the first set time, when the ratio of the real-time flow rate to the set flow rate is continuously lower than a first set value or the real-time flow rate is zero, the existence of the blockage is judged, in the second set time, when the upstream pressure change rate is continuously higher than a second set value, the existence of the blockage is judged, and in the third set time, when the ratio of the real-time temperature to the set temperature is continuously lower than a third set value, the existence of the blockage is judged. As a further optimization scheme of the invention, a liquid storage tank and a heat exchanger are arranged on the filling pipeline, the liquid storage tank is used for filling carbon dioxide into the refrigerating system through the heat exchanger, a low-temperature liquid pump is arranged between the liquid storage tank and the heat exchanger, and when the low-temperature liquid pump alarms abnormally, the liquid storage tank or the pipeline between the liquid storage tank and the low-temperature liquid pump is judged to be blocked. As a further optimization scheme of the invention, when the refrigerating system and the filling pipeline thereof are blocked, the filling rate of the filling pipeline is reduced or the liquid storage tank is stopped from discharging before each pipe section is closed in a segmented mode in sequence. As a further optimization scheme of the invention, when the downstream of the blocked pipe section is purged with gaseous carbon dioxide, the gas source of the gaseous carbon dioxide is a liquid storage tank or an external gas source. As a further optimization scheme of the invention, when the air source is the liquid storage tan