How to Maintain a Steam Methane Reformer Without a Shutdown? Eliminate hot spots, reduce fouling, carry out inspections and other repairs while the SMR is in full operation.
In ammonia and methanol plants, there is often a need for furnace maintenance, or repairs in-between the major shutdowns and production must be reduced, or an emergency shutdown must be considered to maintain processes at optimum, design levels.
IGS Hot-tek Online Services for Steam Methane Reformers
Around 20 years ago, this dilemma faced by SMR operators was recognized, leading to the introduction of a range of services which were designed to be undertaken without having to reduce production or suffer an emergency shutdown. This so-called online work was introduced as a “Hot-tek” range of services carried out by specially trained technicians with the primary emphasis on safe and reliable practices.
Preventing emergency shutdown or reduced production
Operators of Steam Methane Reformers producing hydrogen, ammonia, or methanol have found real benefits in employing IGS (Integrated Global Services) Hot-tek services over the years. The high temperatures required for the process lead to stress on the refractory linings, frequently requiring emergency attention. High fuel consumption requires an efficient operation to maintain economic control; Hot-tek range of services outlined below assist in all facets of the SMR process.
Hot-tek Furnace Repair Services
As the name implies, these services are completed while the process heaters and reformers are hot, being fired and continuing to run at full capacity. Site safety procedures and hot-work measures are met or exceeded for this type of projects. Operational experience and techniques developed over decades in these and similar applications across a range of different industries is essential to the prolonged success and safety record that IGS Hot-tek brings to the table.
Fig 1. IGS Hot-tek services for the Ammonia Reformer SMR
The services cover a range of high temperature cleaning operations, refractory repairs and maintenance all requiring external access and observation by technicians working from outside the units.
1. Furnace Box Access Creation
Inspection ports built into the furnace during construction offer an excellent opportunity for access to areas requiring Hot-tek applications. However, they are placed primarily for observation of the burner combustion quality. Often, they are not positioned in the ideal spot for online maintenance activities. For these cases, IGS Hot-tek developed a safe, reliable method to create access points through the shell and refractory lining and to place a sealed, removable door so that access may also be achieved at a later date. The service is identified as Hot Access Creation.
2. Heater Inspection Services
Hot Inspection Services employ two different types of specialized equipment. The unique Lancescope® is a high temperature camera system which is inserted into the process heater to view areas that are not directly visible by line of sight. Patented water-cooled, or air-cooled lances are used to reach distant parts of the heater.
The Lancescope provides a close-up, or wide angle, real-time images of any area, using lances up to 30ft (10m) long. The digital camera system displays and records video or still images.
The Lancescope can be used either as a stand-alone inspection tool, or in conjunction with other IGS-Cetek online activities to enhance observation of each special service inside a firebox.
Fig 2. Image showing Refractory Failure
Fig 3. Lancescope® and a Typical Lancescope
Infra-Red Thermography is also used extensively throughout IGS Hot-tek’s product offerings as a basis for a fired heater evaluation process, or again as a tool to identify the degree and precise location of hot spots caused by operational or maintenance issues.
3. SMR Convection Section Tube Cleaning
The convection sections of Steam Methane Reformers provide feed pre-heat and generate the steam required in the process. Any loss of efficiency of heat transfer has a significant effect on the overall efficiency of the production processes.
Tubes in the convection section are configured and designed to capture heat in the flue gases vide leaving the radiant section. Most of the tubes are finned, to present a large surface area, increasing the efficiency of convective heat transfer. The fins provide an effective filter medium, however, capturing dust, fibers, etc. derived from contaminated combustion air, or from the refractory lining in the radiant section. Refractory ceramic fiber linings in the radiant section present a particular problem, since they are readily generated and easily captured by the fins, owing to their fibrous nature.
As fouling increases, convection section duty is lost and process pre-heat and especially steam generation is reduced, affecting production rates.
Often operators must wait until a shutdown to complete a manual cleaning, or to use a wet, chemical process. Water and chemicals should never contact refractory linings in such high temperature units, where refractory specifications are so important – and must be protected. IGS introduced an online Hot-tek method for cleaning finned convection section tubes using a dry process, solid CO2 blasting. Access is made through inspection ports, or through access points created by Hot-tek technicians. The cleaning leads to a reduction in fired duty, reduction in stack temperature, increases in process pre-heat and steam generation and a return to efficient operation.
Fig 4. Steam Methane Reformer Convection section fouling Fig 5. Steam Methane Reformer IGS Hot-tek Hot Convection Tube Cleaning (HCC)
4. SCR Vacuuming Service
SMR equipment is a significant source of NOx emissions because of the high operating temperatures and the amount of fuel consumed. Selective Catalytic Reduction (SCR) units are typically added to SMR equipment to reduce NOx emissions. In use, flue gases are normally treated with ammonia and directed through banks of catalysts which convert the NOx to H20 + N2.
During SMR operation, dust and fibrous particles collected by the flue gas are readily captured by the catalyst, resulting in a high-pressure differential across the catalyst and operational issues including high electricity consumption of the ID fan and ultimately reduced production.
IGS introduced a patented Hot Vacuuming Service which removes the fouling material and restores the operation to an “as-new” condition. The service, combined with IGS Hot Access Creation and Hot inspection Services, does not interfere with production, and no damage is caused to the catalyst.
Fig 6. Steam Methane Reformer IGS Hot-tek Hot Vacuum Service
5. On-line Refractory Maintenance & Repair Services
As mentioned earlier, refractory linings in SMR units become stressed because of the high temperatures necessary for the process conditions. Perhaps the most beneficial and welcome online service offered by IGS Hot-tek is the Hot Refractory Repair service. This service is normally provided in combination with Hot Inspection and Hot Access Creation services.
Confirmation of the location of the problem area is readily identified using Infrared Thermography.
Fig 7. Inspection of a Typical Hot Spot in a Fired Heater
IGS uses a unique Hot-tek “Basket” support system to install and secure the refractory repair material. The baskets are welded to the steel shell and remain in place, together with required anchoring systems for the life of the repair. The Hot Refractory Repair system has been used successfully on all types of refractory lining, including RFC, and in all configurations – vertical and horizontal, including roofs.
Fig 8. Hot-tek Refractory repair System on the roof of a vertical cylindrical fired heater to close the joint between old refractory and freshly installed insulated panels.
While the online refractory repair is viewed as a rapid, or emergency fix, the life of such a repair is multiple years, but it is recommended that they should be inspected at a convenient shut-down and replaced by a conventional cold refractory repair if needed.
Your Emergency is Our Routine
The capabilities and expertise of IGS Hot-tek specialists have been called for numerous and varied online applications, including installation of burners and supports, tube hangers and securing individual errant process tubes.
For more information visit integratedglobal.com.