The problems faced by grease processing companies in using condensate recovery devices

It can be seen from the poster’s question that your company attaches great importance to steam condensate recovery. As the poster mentioned, steam condensate recovery is of great value, not only to maximize the recovery and reuse of heat energy, but also to create considerable economic benefits.

Steam is coming out of the trap

From the poster’s description, we can know that your company previously used an open recovery device, that is, the condensed water was first discharged into a soft pool, and then The water temperature drops to 70°C (in order to avoid high-temperature pumping cavitation) and then recycled. During this process, the pressure drops from 0.7MPa to 0. Since the temperature of the condensed water and the air pressure have a one-to-one correspondence, when the pressure drops from 0.7MPa At 0:00, the temperature of the condensate water drops from 165°C to 100°C, and the high-temperature condensate water at 65°C is converted into secondary flash steam and discharged. This is the part of the steam that the poster sees is still coming out after recycling.

As we all know, the heat exchange equipment in the grease industry has high steam pressure. Once something is not considered when selecting a steam condensate recovery device, problems can easily arise. Traps all have a steam leakage rate. Generally, the steam leakage rate of domestic traps is above 3% to 5%. The steam leakage rate of imported traps is generally around 1%, but they are also much more expensive than domestic ones. The function of the trap is to drain water and block steam. Generally, the trap will not leak under normal operating conditions. When the trap is damaged, if it is in the closed state, the output of condensate will be interrupted immediately, and it can be stopped for maintenance (affecting production) , or the bypass is in a normally open state, and part of the steam heat energy is discharged without being fully released. If it is fully open or half open, it will not affect the output, but it will be in a "steam" state. In China, as long as the trap can still be used, it will not be replaced immediately. Therefore, the normal operation of the trap (i.e. steam leakage rate <3%) does not exceed 10%, and the leakage exceeds the standard (i.e. steam leakage rate > 5%) accounted for 60%, and the remaining 30% were serious leaks (i.e. air leakage rate >10%). This part of the air leakage constitutes another part of the "gas" seen by the poster.

Some people also say that the air leakage will not be serious if the trap is replaced with another type. In fact, this statement is quite imprecise, because the steam leakage rate is relatively low when the trap first operates well, but the water trap The valve is a wearing part and will still emit a large amount of steam if it does not operate properly after being used for a period of time.

We have done such a project before, and we are also a grease processing company. It was in Inner Mongolia. Before we cooperated with their company, they had been using domestic traps, but the air leakage was very serious and a large amount of steam was released. Later, the boss felt very distressed, so he switched to imported traps. The cost of replacing a trap is about 300,000 to 400,000.

About water storage

As for why there is water in your equipment, the reasons are as follows: The hydrophobic principle of the trap is that under isobaric conditions, condensate can flow to the trap by gravity. Grease processing companies generally use multi-layer heating materials. The dry humidity and heating time of each layer of materials are different, resulting in different temperatures and pressures in each layer. The pressure is slightly different. The layer with a higher temperature is pressed against the layer with a lower temperature. Condensed water is difficult to remove, the equipment "holds water" and the heat exchange efficiency is poor. Once the equipment holds water, it will not only affect production, but also require frequent bypasses, resulting in a large amount of waste of high-priced steam.

This is also one of the reasons why the boiler evaporation capacity of some enterprises has never reached the designed evaporation capacity. A case we did in Jiangsu showed that this problem was very serious. Water storage in equipment will inevitably affect heat exchange efficiency. The most ideal state of a trap is to discharge all the condensate water produced and not leak at all, but this type of trap does not exist today. Therefore, the use of traps will inevitably have some impact on heat exchange efficiency, which is what our industry calls energy saving and heat exchange.

Once energy saving and heat exchange conflict, the energy saving effect will be greatly reduced. This is also one of the important reasons why most steam condensation water equipment is dismantled and abandoned after being installed.

About reciprocating pumps and powerful suction recovery machines

As for reciprocating pumps and powerful suction recovery machines, they are both closed steam condensate recovery devices, in terms of technology and energy-saving effects. It is indeed better than the open recovery device, but these two devices still use traps, so if these two devices are installed, the above problems still cannot be solved. At the same time, some other issues will be added. For example, the use of reciprocating pumps will also produce "virtual pressure phenomenon" and shorten the life of the equipment.

Therefore, as long as it is a grease processing enterprise or other enterprise with complex steam working conditions, it is generally not recommended to choose equipment with a trap. As long as a trap is used, air leakage and water accumulation in the equipment are inevitable. and other problems, which will further affect production and, more seriously, paralyze the system.

Now, the poster is worried about whether energy saving can be achieved on the basis of promoting production. The answer is yes. Moreover, steam and condensate can be recovered at the same time.

As for the problems existing in the steam condensate recovery process in the oil and fat industry, our company (Yitongda Steam Energy Saving) has rich practical experience and a solid theoretical foundation. It has developed research and development based on many years of in-depth research on the oil and fat industry. The trap-less steam condensate recovery system can recover steam and condensate at the same time. There have been hundreds of successful cases in the national oil and fat industry, such as Hubei Jianli Jiayi Grain and Oil Technology Co., Ltd., Hubei Hongkai Industry and Trade, and Hunan Zhangjiajie Jinlu Grease Co., Ltd., Jiangsu Dongtai Blue Ocean Grain and Oil Co., Ltd., Jiangsu Shuangshan Group, Jiangxi Gaoan Qinghe Grease Co., Ltd., Shandong Jiaxiang Jinyuan Grease Co., Ltd., etc. have all installed our products.

Since our system does not use traps, it effectively avoids the above problems mentioned by the poster. At the same time, before designing the system, we insist on achieving the best heat exchange efficiency of the system and ensuring that the entire system is With optimal operation as the core, we can not only maximize the recovery of steam condensate, in other words, you will not see any steam coming out after installation. At the same time, we can also solve problems such as insufficient evaporation and weak steam. , while reducing energy consumption and reducing internal management costs.

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