There are certain best practices that you can leverage to protect your condensate system from corrosion and other hazards that can pose a safety risk, besides reducing the efficiency of your system. A good industrial steam boiler training program is your first and most important line of defense against condensate system corrosion. Regular steam boiler maintenance can greatly mitigate the risk of corrosion.
To improve the efficiency of your system, you need to bring down make-up water expenses and reduce the cost of chemicals for treating this water. You must also recycle the maximum amount of treated water for reuse in your boiler system. Several different factors can have an impact on your condensate system.
These include the following:
- Insulation method
- Positioning of the condensate connections within condensate headers
- Position of the condensate line in relation to the process equipment
- Condensate line sizing
1. Material Choice
To minimize the chances of corrosion and other hazards, it is necessary to use the best quality material in the condensate system that will last long to provide reliable service. Material selection is critical since the system will be exposed to the potentially corrosive action of carbonic acid.
One of the best materials that you can rely on for a highly functional and dependable condensate system is stainless steel. The right grade of stainless steel will give your condensate system the ability to withstand and resist corrosion for a much longer time frame and, thus, extend the operational life of your system.
However, stainless steel is expensive. If economic consideration is hampering your ability to buy stainless steel equipment, you may have to use carbon steel, which is not as durable and may require quicker replacement. If using carbon steel for this reason, make sure that you use a thicker gauge like schedule 80 pipe since the thickness will allow it to last longer under corrosive conditions. Under the same corrosive environment, a greater wall thickness will outlast thinner pipes.
2. Connection Types
Condensate systems need tubing with tube connectors or welding for it to work as intended. However, there is the risk of leaks. Condensate piping is exposed to high temperatures and possibly fluctuating temperatures at times due to which it will expand or contract accordingly. A lot of steam components are still available with threaded connections.
Although they are easy to set up, the main issue with threaded components is that threads are inherently susceptible to leakage problems. These are often at the highest risk of attack from corrosive carbonic acid and are vulnerable to failure. Threaded systems are also not suitable for accommodating expansions and contractions that steam boiler operations inevitably entail. Expansion and contraction could be another major cause of leakages.
Here are some connections for condensate system components arranged according to preference.
Welded joints
Tube material fitted with tube connectors
Flanges
Threaded pipes (use only if there is no other option available)
3. Tubing vs. Piping
Although tubing has its own relative advantages, it is used to a lesser degree. Better connections are available for system components in the form of tubing. Welding of thinner pipe diameters can be an expensive, painstaking and time-consuming task. You can cut down the welding time and number of welds required by deploying tubing material where possible. This is advantageous since welds are often at high risk of corrosion.
4. Maintenance Capability
The condensate system should be designed with maintenance considerations in mind. It should be easy for maintenance personnel to take apart the different components for repair, inspection and maintenance. Systems that are not designed with high priority for maintenance may be more difficult to maintain. This might prove to be problematic since maintenance is a vital defense against corrosion. All components and devices installed within the system, including condensate pumps, steam traps, tubing and piping, should be designed and installed with maintenance considerations in mind.
5. The Right Sizing for Tubing and Pipes
Calculations for your condensate line design are a bit different than other lines because of the nature of the fluid they are carrying. Condensate piping carries water in two phases: steam and liquid. Thus, the size of the condensate piping/tubing will be somewhere between steam lines and hot water lines. Condensate lines that are too small may suffer problems from excessive back-pressure and may require more frequent and costlier maintenance.
Thus, for well-maintained condensate line sizing, it is necessary to consider key factors like the flash steam load, neglect factor and the condensate liquid load.
Special care must be taken while calculating velocities in condensate pipes for if the velocity is too high, then there may be water-hammer and other destructive effects that can possibly lead to structural damage as well as greater corrosion.
6. Neutralizing Amines
Neutralizing amines is one important way of reducing carbonic acid attack. Examples of chemicals that can protect against carbonic acid corrosion include diethyl aminoethanol, cyclohexylamine and morpholine. These chemicals can blend with steam and condense just like carbon dioxide. These chemicals work by neutralizing carbonic acid and raising pH levels. However, they still do not work against oxygen pitting, which is another important cause of corrosion.
7. Filming Amines
Filming amines, as their name suggests, can act as protective barriers. Thus, they can keep piping and other components safer against the action of oxygen and carbonic acid. A neutralizing amine will be required since it is necessary to keep the water pH in the 6.0 to 7.5 range. But there is still another problem with filming amines. They are susceptible to erosion. Hence, you will need to use corrosion coupons for monitoring the corrosion levels. There is also the possibility of fouling with filming amines. Thus, filming amines should be used, keeping in view their drawbacks and taking steps to reduce these adverse effects.
8. Volatile Oxygen Scavengers
To keep your condensate system safe from the effects of the oxygen system, volatile oxygen scavengers are another possibility. Diethylhydroxylamine is one such chemical. DEHA can provide better performance than filming amines and has fewer limitations.
For more information with respect to condensate system protection, you should get in touch with a reputable company like Campbell-Sevey. We can help you with industrial steam boiler maintenance and boiler maintenance training. Contact us today.
