Petrochemical industry products are often associated with continuity, high temperature, high pressure, scaling and strong corrosion. It is better to keep the equipment safe from these cases and avoid a potentially big disaster with careful and timely handling. Therefore, if any company considers a part of its initial capital for overhaul, it will be safe from these problems.
Maintenance and major repairs are expensive, but against the cost that may be caused by the failure that It will have serious consequences for the factory, it will not be a very large amount. In case of accidents, even short-term stops in production may occur, which, in addition to the loss of non-production, will cause customer dissatisfaction and damage to the reputation of that production unit.
What is overhaul?
Overhaul or the English word Overhaul means basic repairs, which can be repairs of anything. It includes the smallest parts of mechanical and electronic equipment to industrial devices and tools.
Basic repairs are a completely specialized work; Because in today's era and due to the complexity of industrial devices, these equipments also require specialized repairs. Therefore, it is necessary to use expert forces in mechanics, electronics, industries and safety for repairs. Specialized repairs are required for the basic repair of refineries and other equipment and industrial networks. These repairs include dismounting and remounting, full inspection, repairs, and engine inspections.
What is the purpose of overhaul?
Refineries and petrochemical industries, like any other factory, need repairs after a period of operation. In addition to preventing possible defects, these repairs can also guarantee the health and safety of the systems. These problems include:
Internal blockage
Most of the problems of these equipments are the accumulation of scale, and the main masses are: > 🔰 Heavy polymer materials and coke are among the materials that cause blockage of paths and equipment. If not dealt with on time, they may cause accidents.
🔰 Refinery coolers are another place where sediment and debris and even hard water materials will block the passage.
Surface clogging
Clogging may occur on towers and trays. In this case, it will reduce the efficiency of the devices and premature wear of the equipment.
Corrosion and abrasion
Materials such as sulfur and nitrogen along with the products when they pass through the pipe and equipment cause corrosion and wear of the equipment and metals in the parts due to the speed, heat and pressure. These corrosions and abrasions caused by these materials will eventually cause the thickness of the equipment to be lost. to give If this happens during the operation of the refinery, it may lead to accidents, fires and massive explosions.
Pollutions and incidents happen over time in the stages of refining oil and products because of the aforementioned defects. This is where overhaul operations or major repairs become necessary. This operation has special standards in the world. It is implemented in all refineries according to the plans and according to the required schedule.
Know the overhaul and overhaul procedures
In the overhaul, all the equipment and parts that have been closed before are opened and after de-scaling and complete washing, possible defects are identified and fixed. Also, if needed, new parts and complete renovation of the equipment will be done. After completing the review process, all parts are closed and started. All these things are done in steps which are:
Equipment inspection
Corrosion occurs in different parts of the pipes and in the areas where the material flows, and usually these points are variable. Therefore, these points should be inspected and controlled more sensitively and accurately in the pipes where the materials pass with more speed and intensity.
If the corrosiveness of the pipe allows the equipment to work again, clean it. Otherwise, if the corrosion of the pipe is excessive, it is better to replace that part.
Insulation
Sometimes the amount of corrosion in the parts that have insulation is not correctly determined. Sometimes even some devices can't diagnose it. The areas that have insulation, especially when there is moisture around the device, make troubleshooting difficult; As a result, the best control and inspection should be done by the operator. Otherwise, these corrosions remain hidden from the eyes and small and sometimes big accidents may occur.
Inspection of sensitive units
Catalysts of refineries are among the sensitive units that are more prone to scale than other units and over time, pollution, including sulfur, accumulates on its equipment. Nitrogen and other metals with the deposit they create on the catalysts cause a decrease in the efficiency of the catalyst and reduce the life of the equipment. This issue causes this unit to be checked and restored more carefully and obsessively during the overhaul operation.
During the restoration of the catalytic unit operation during the major repairs of the refineries, the coke deposited on the catalyst is generally burned. Catalysts are completely regenerated during this process and return to their original state
What is the standard time interval between two overhauls and major repairs?
The standard time interval between two overhauls for refineries has been three years in the past. It is true that with the advancement of equipment to detect defects and corrosion, this time has been changed to once every 4 years for some equipment, but for catalytic units due to the sensitivities mentioned, and units such as the distillation unit are among the parts where the time interval for major repairs is the same as 3. It has been years and it has not changed.
How much time is required for overhaul?
Well, as it has been said so far, the time required for the overhaul is important, and during this period, the work of the refineries will be closed. Although this time is also variable for different parts, because it depends on how heavy or light the unit is and the equipment that needs repair in that unit. Also, due to the high volume of compressors, equipment, towers and required containers, they need more time.
When is it better to do major repairs?
Basic repairs are done before the device reaches a state of failure or failure. This operation is a predictable activity and plays the role of preventing breakage, perforation, accident and explosion in refinery equipment.
As you know, overhaul work is done according to the scope of the project. Determining the scope of the project is considered as the main key and the problem of major repairs.
What points should be observed during major repairs?
