Views: 2 Author: Site Editor Publish Time: 2021-12-17 Origin: Site
Winter is cold, in order to ensure the safety of chemical plant production, anti-freezing, anti-coagulation work is very important. In order to prevent the occurrence of all freezing accidents, according to the characteristics of the device, the anti-freezing and anti-freezing work should also be carried out in accordance with the policy of "prevention first, elimination second". Strengthen the collection, delivery, use and management of goods easy to freeze, easy to freeze, according to the basic method to prevent in advance, according to the provisions of careful inspection, reasonable treatment of frozen block problems, to ensure the purpose of safe production.
One, anti-freezing method
Chemical plant common anti-freezing, anti-coagulation methods are empting, heat preservation, heat tracing, circulation and other methods, winter anti-freezing, anti-coagulation should be based on equipment, pipeline running state, combined with the problems and experience in the process of anti-freezing in previous years, take one or more of the methods.
1. Empty. The anti-freezing and anti-coagulation methods of emptying can be roughly divided into three categories:
First, the ground intermittent operation or long-term unused equipment and pipelines can be emptied according to the following steps:
(1) Close the relevant valve, add a blind plate if necessary to prevent leakage in the valve;
(2) open the high exhaust valve and low exhaust valve to empty the material in the equipment;
(3) Purge and replace residual materials with nitrogen;
(4) Always open the low point drainage valve and check it regularly.
Wo is the underground valve well facilities, pipeline empting, mainly without heat tracing fire facilities (such as water cannon, fire hydrant), from the valve well close the root valve, through the drainage valve to empty the upper part of the valve, and keep the drainage valve normally open, fire gun head down.
Three is the temporary use of equipment, pipelines or hoses, after the use of timely emptying tube medium, with nitrogen purge clean; If conditions are available, it can be placed in a thermal insulation workshop.
2. Heat preservation. From the perspective of anti-freezing, chemical plant insulation mainly involves the following three aspects:
First, the equipment, pipeline and its accessories should be insulated with thermal insulation cotton. Before winter, the problems in previous years should be combined with this work should be carefully investigated and improved, especially paying attention to the insulation of equipment, pipeline end, blind end and on-site pressure gauge without heat tracing and relying only on material temperature to prevent freezing, so as to ensure that the insulation is in place.
Second, the plant and other indoor space sealed warm, check and confirm whether the plant doors, Windows and curtains are in good condition, timely use of heating plant.
Three is the underground valve well seal warm, for valve well, the use of plastic sheet sealing work in advance, when necessary to take heat preservation measures.
3. Heat tracing. In terms of winter anti-freezing, the common heat tracing media are hot water tracing, steam tracing, electric tracing. Hot water tracing is suitable for the condition that the operating temperature is not high or high temperature tracing medium can not be used. Steam heat tracing is generally used for heat tracing when the operating temperature of the medium in the tube is less than 150℃.
Electric tracing is not only suitable for steam tracing in all kinds of situations but also for heat sensitive medium pipeline. It can effectively control temperature and prevent overheating of pipeline temperature. It is suitable for heat tracing of pipes or equipment scattered or far away from the gas supply point and equipment with irregular shape.
The selection of heat tracing media should be combined with the nature of materials, index requirements, construction difficulty, operation cost and other aspects of selection, and in accordance with the specifications for construction, in order to achieve anti-freezing, anti-condensation at the same time, to avoid new problems.