by Integrated Global Services (IGS)
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Fired heaters have the greatest running cost in a refinery or a petrochemical site. If any one of these heaters is 1% or 2% inefficient it can consume an additional $1 million in fuel over a year or result in millions of dollars in lost revenue. High fuel consumption also translates to high emissions.
Catalytic reformers, steam methane reformers, fired heaters with process pre-heat, and ethylene furnaces among others face unique challenges to keep operational efficiency optimal.
We will review a range of fired heater services that can help deliver:
High-Emissivity Ceramic Coatings for Process Tubes and Refractory
Cetek Ceramic Coatings provide a durable, protective, thin-film layer on the outer surfaces of process tubes, which prevents oxidation, corrosion, and carburization of the metal and maintains the tube thermal conductivity coefficient close to new tube conditions. Tube coating can be applied in conjunction with a refractory coating, increasing the benefit and encapsulating the refractory.
The Problem: Low Emissivity Refractory Material
In fired heaters and tubular reformers, the necessary thermal energy to drive the endothermic processes is provided by burning a fuel/air mixture and transferred to the process by three heat transfer mechanisms: radiation, convection, and conduction. The primary means of heat transfer is radiation.
At the process heater operating temperatures, new ceramic fiber linings, for example, have emissivity values of around 0.4. Insulating fire brick (IFB) and castable materials have emissivity values around 0.6. These materials have been designed with structural considerations and insulating efficiency as the primary requirements. They tend not to handle radiation most efficiently.
Cetek Ceramic Coatings with emissivity values above 0.9 have been designed specifically to supplement the radiation characteristics of the refractory surfaces. The coating has now become an accepted means of improving the efficiency of radiant heat transfer, leading to energy savings as well as environmental and reliability benefits.
The Problem: Radiant Tube Oxidation
Radiant tubes in fired heater applications in oil refineries are typically steel alloy, ASTM A335 P22, P5, or P9 which contain 2.25%, 5% and 9% Cr respectively. Radiant tubes oxidize at operating temperatures and scale will grow continuously on the surface, often reaching 2mm in thickness in higher temperature / high heat flux units.
The layers of oxide scale are highly insulating and represent a significant barrier to conductive heat transfer to the process fluids. During fired heater operation, to overcome the insulating effects of the oxide and scale layers, it is necessary to increase the firing rate, to maintain the heat flux through to the process feed inside the tubes.
Cetek’s High Emissivity Ceramic Coating system ensures maximum conductive heat transfer for the process.
Layers of fouling and scale prevent accurate determination of tube metal temperature, reducing the reliability of those measurements. Cetek applies a thin layer of ceramic coating which provides a consistent temperature differential between the outside surface and the metal tube. This results in a significant improvement in the reliability of tube metal temperature determination.
Read: ‘Improving Radiant Efficiency in Catalytic Reformers’
Tube Tech’s fired heater convection section cleaning service is recognised by world-leading refining and petrochemical companies as the most effective technology to achieve OEM performance clean fired heaters.
90% clean guarantee even on the most fouled assets.
Fired heater fouling is a costly problem for refineries around the world. Heater intake collects 1 ppm airborne particulate whilst in service, which results in deposits of 2.5 tonnes over 12 months either landing in or travelling through the heater.
These deposits most commonly land in the base of the Radiant Section, on Convection Tubes, or in the Air Pre-Heater.
The Solution: Robotic Convection Section Cleaning
Traditional cleaning methods are only able to clean 30-45% of the total fouled area. Tube Tech, backed by multi-million-dollar European funding, has developed a Rover system that penetrates deep between tube rows to remove even the most stubborn fouling.
Read: ‘Tube Tech Restores Convection Section at Petrochemical Plant in Bangkok’
Watch: The Effects of Fouling in Fired Heaters
Online Maintenance & Emergency Services (During the Heater’s Normal Operation)
Hot-tek™ is the industry leader in hot maintenance and online fired heater repair and cleaning techniques and holds multiple patents on the approach, methods, and tools used to carry out these services. The approach is customized for every client’s needs. Often, multiple Hot-tek™ services are employed simultaneously to achieve the best results.
Hot spots in the shell
Failure of refractory material can lead to energy wastage, poor performance and even complete shutdown of your fired heater.
Hot Refractory Repair Services may be made gaining access through the heater steel shell directly behind the damaged area. Minimal openings are used to insert specially designed components to support the repair material. This technique offers a semi-permanent repair method lasting at least until the next planned turnaround.
Read: Latest Hot Refractory Repair Case Study
Watch: Hot-Tek’s Hot Refractory Repair Service
The Problem: High Bridgewall temperature
An increase in bridgewall temperature can be a symptom of excessive fouling of the fired heater’s radiant tubes. These tubes tend to oxidize under operating conditions. Layers of scale and soot can grow with time to a degree that it insulates the tube fireside from the radiant heat. It is even more dangerous if there are several years until the next scheduled shutdown.
Hot Tube Descaling service removes radiant section process tube fireside soot, scale, and fouling during furnace operation. The process uses unique water-cooled lances and cleans the tubes while the heater continues to function normally. The process utilizes consumable abrasive media resulting in no increase in emissions.
Watch: About Hot Tube Descaling
The Problem: Misaligned Radiant Tubes
Occasionally, tube supports (wall and roof) in the radiant section of process heaters fail, allowing the process tubes to potentially become misaligned (sagging or bowing) or even worse, rupture. This can cause significant disruption to productivity and can result in costly unplanned shutdowns.
Hot-tek has developed an online repair service to stabilize the process tubes while the heater is in full operation. Our service can prevent shutdowns and allows the operator to run the unit until the planned turnaround dates.
Read: Latest Hot Tube Stabilization Case Study
Watch: About Hot Tube Stabilization
The Problem: Fouled Convection Section
Low steam production, low process pre-heat, and high stack temperatures are some of the symptoms of fouled tubes within a convection section.
Hot Convection Cleaning process removes convection section tube fouling & scale during furnace operation. The tube cleaning process uses consumable abrasive media projected through specially designed application lances to blast away years of accumulation, while the heater is in service.
This emergency or intermediary solution prevents losses associated with taking the heater offline. However, we advise a Planned Preventative Maintenance (PPM) approach, and our Tube Tech service provides industry-leading offline cleaning services to prevent emergency cleaning situations.
Read: Latest Hot Convection Cleaning Case Study
Sometimes, an issue can arise in high temperature fixed equipment, but you can’t see the cause or the exact location of the problem. Cetek’s Lancescope™ heater inspection tool allows a high-temperature furnace inspection to be carried out to determine the scope of the problem, often avoiding an expensive shut down of the heater.
Cetek’s Lancescope™ system provides real-time, close-up, or wide-angle views of virtually any area inside a fired heater, or other high-temperature equipment while it is still in operation.
The hot inspection system uses a state-of-the-art digital camera system, which provides clear, detailed images of problem areas up to 3000°F (1650°C). The furnace inspection system can be inserted into openings as small as 2.75” (7cm) and reach up to 30ft (10m). In applications below 1000°F (540°C), the heater inspection system provides illumination via a high-temperature light source for optimum clarity.
A thorough inspection provides data needed for other Hot-tek online services.
Watch: About Hot Inspection Services
SCR efficiency problems cost ammonia plants millions of dollars annually. This happens due to fibrous material, mostly refractory fibers breaking free from degradation over time, plugging the face of the catalyst, causing poor NOx removal, high pressure drops, and poor ammonia mixing.
The Problem: Refractory Fibers Plugging the Catalyst
This results in system derates and forced outages to clean the catalyst face. Every day the facility is an outage, it cost the company approximately $1M in lost production. In addition, the costs of shortened catalyst life lost production during derates, and excessive ammonia usage contributes to an estimated $3M + annual cost due to this buildup.
The IGS patent-pending dual-stage filtration screen and online cleaning system capture the fibrous material in the gas stream prior to it reaching the catalyst face. The screen online cleaning system pushes the captured material out of the primary gas stream and into a collection area where it can later be removed. Preventing buildup on the catalyst ensures proper flow distribution, minimizes pressure drop and extends catalyst life.
The Solution: Mixing Plate System
The IGS patent-pending flow mixing system is designed to maximize ammonia mixing prior to the catalyst to reduce ammonia usage and ensure an even ammonia concentration distribution through the catalyst, which improves DeNOx and preserves the catalyst reactivity. This can be installed in conjunction with the filtration screen or even as a standalone improvement.
These fired heater services are designed and delivered turnkey by Integrated Global Services (IGS). IGS is a global provider of surface solutions for mission critical equipment solving complex problems in the Oil and Gas, Petrochemical, Power, Metals, Pulp & Paper and other industries.
How to Cut Emissions & Fuel + Increase Capacity in Fired Heaters. Register, here.
Contact us at info@integratedglobal.com to see how we can improve your fired heater efficiency.
by Integrated Global Services (IGS)
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