Point source emissions have been targeted for control systems. Consequently VOC concentration levels have diminished and have became more dilute. This equates to more VOC abatement equipment with higher operating costs. Plants around the globe are under pressure to reduce operating expenses while continuing to be environmentally compliant. In many parts of the world it becomes very difficult where natural gas, alternative fuels and electricity are costly.
Air Pollution control manufactures are coming to terms on developing new methods to reduce equipment operating costs on developmental equipment and operational plant systems. Plant waste gas streams considered as air pollution can either be recovered as solvents or destroyed by thermal oxidation. Should the solvents be re-useable a converting process, recovery systems are preferred as a way to minimize the plants operating costs. Many times the only value recovered as a fuel source. Recovered volatile organic hydrocarbons are many times used to heat a plant process and are eventually destroyed by an oxidation process.
Thermal Efficiency
Regenerative thermal oxidizer (RTO) is the most common oxidation technology and is used very often within the United States, and is rapidly gaining acceptance worldwide. The main benefit comes from the very high thermal efficiency, creating an attractive method for low concentration processes with high volumes of waste. VOC abatement is accomplished by elevating the process stream to a temperature at which the hydrocarbons suddenly react with combustion and process oxygen (usually between 1,400–1,800ºF). A Regenerative thermal oxidizer utilizes the heat recover chambers (ceramic media) to pick up and reuse the BTU value created by the oxidation process. After the heat has been captured within the ceramic media bed it is used to preheating the incoming process air.
Regenerative thermal oxidizer's heat recover beds consist of two or more areas of ceramic media, referred to as heat recover chambers or regenerators. One heat recovery chamber absorbs and stores heat from the leaving purified hot process stream and the other heat recovery chamber applies the stored BTU energy or heat to the incoming plant process waste gas stream. When the heat recovery chamber acquiring the BTU's or heat begins to become infused, the emitting heat recovery chamber becomes exhausted, to cause the transfer of BTU's or heat a group of valves change the process airflow to effect the transfer from one heat recovery chamber to the other, then reversed on an time or temperature basis.
Regenerative thermal oxidizers have a proven technology; facilities are continually demanding that air pollution control abatement systems become more efficient to reduce plant costs. In the past years engineering departments have developed new heat transferring sinks, distinctive oxidation technology and burner optimizing technics.
"HRC" heat recovery beds are made up of ceramic saddles which are also know as random packings, these are placed inside a insulated chamber refered to as the heat recovery area or bed. The process flow through the saddles and is forced to take many directional changes. With the turbulant nature of the process flow and the drop in pressure elevates with the square of the process flow.
The structured packing is made up of a ceramic monolithic blocka> ceramic monolithic block, often composed of silica alumina ceramic material. The individual structured block approximates 6" to 12" inches high, 6" inches long and 6" inches wide, and has between 16 and 64 parallel passages per square inch, running from top to bottom. The structured ceramic media block's attributes allow for a larger process flow velocity through the heat recovery bed with a much smaller space footprint.(RTO) auto thermal conditions and be self-sustaining. Under these conditions, no burner would be required. Once the heat exchange media is saturated and hot enough to elevate the airstream above self-ignition levels, the burner is turned off and combustion blower runs at a minimum position. Natural gas or methane is safely injected into the incoming airstream, enriching it to levels necessary for self-sustaining operation.
Larger abatement capacity can be acheived by greater heat recover chamber velosity through the existing regenerative thermal oxidizer equipment. Utility consumption is higher on older heat recovery beds with saddle configurations due to the pressure drop. Â
Replacement of an ceramic saddle heat recovery bed with more efficient ceramic monolith can purportedly not only reduce the pressure drop across the heat recovery chamber for existing capacity, but provides almost a 40% increase in process stream flow capacities with the existing motor and fan assemblies.
The Burners Go Off
On standard regenerative thermal oxidizers, a fuel burner provides the elevate heat required for destruction. This latent heat amount is the difference that is not trapped within the "HRC" heat recovery bed. This amount is around 5%. However, if the process stream high enough VOC levels the hydrocarbons would provide enough energy for
Auto thermal conditions improves the thermal efficiency of an regenerative thermal oxidizer by decreasing the need for large amounts of combustion air being produced, which mitigates any imbalance in process flow between the two heat recovery beds. Â
Burners are the largest contributor to the formation of NOx by running the system at or closer to the auto-thermal state an improvement in NOx emissions will occur by reducing the high flame temperatures. New low NOx burners reduce much of these emissions. By reducing or shutting off the burner a shape decrease in NOx formation will occur.
The Solution
It is important to understand and examine the plant process stream and the waste constitutes. In applying the correct technology, investigate both the waste stream and process to be abated. Carefully review current and any future regulations, then consider local regulations, space, utility costs to select the correct plant solution.
Air Pollution control manufactures are coming to terms on developing new methods to reduce equipment operating costs on developmental equipment and operational plant systems. Plant waste gas streams considered as air pollution can either be recovered as solvents or destroyed by thermal oxidation. Should the solvents be re-useable a converting process, recovery systems are preferred as a way to minimize the plants operating costs. Many times the only value recovered as a fuel source. Recovered volatile organic hydrocarbons are many times used to heat a plant process and are eventually destroyed by an oxidation process.
Thermal Efficiency
Regenerative thermal oxidizer (RTO) is the most common oxidation technology and is used very often within the United States, and is rapidly gaining acceptance worldwide. The main benefit comes from the very high thermal efficiency, creating an attractive method for low concentration processes with high volumes of waste. VOC abatement is accomplished by elevating the process stream to a temperature at which the hydrocarbons suddenly react with combustion and process oxygen (usually between 1,400–1,800ºF). A Regenerative thermal oxidizer utilizes the heat recover chambers (ceramic media) to pick up and reuse the BTU value created by the oxidation process. After the heat has been captured within the ceramic media bed it is used to preheating the incoming process air.
Regenerative thermal oxidizer's heat recover beds consist of two or more areas of ceramic media, referred to as heat recover chambers or regenerators. One heat recovery chamber absorbs and stores heat from the leaving purified hot process stream and the other heat recovery chamber applies the stored BTU energy or heat to the incoming plant process waste gas stream. When the heat recovery chamber acquiring the BTU's or heat begins to become infused, the emitting heat recovery chamber becomes exhausted, to cause the transfer of BTU's or heat a group of valves change the process airflow to effect the transfer from one heat recovery chamber to the other, then reversed on an time or temperature basis.
Regenerative thermal oxidizers have a proven technology; facilities are continually demanding that air pollution control abatement systems become more efficient to reduce plant costs. In the past years engineering departments have developed new heat transferring sinks, distinctive oxidation technology and burner optimizing technics.
"HRC" heat recovery beds are made up of ceramic saddles which are also know as random packings, these are placed inside a insulated chamber refered to as the heat recovery area or bed. The process flow through the saddles and is forced to take many directional changes. With the turbulant nature of the process flow and the drop in pressure elevates with the square of the process flow.
The structured packing is made up of a ceramic monolithic blocka> ceramic monolithic block, often composed of silica alumina ceramic material. The individual structured block approximates 6" to 12" inches high, 6" inches long and 6" inches wide, and has between 16 and 64 parallel passages per square inch, running from top to bottom. The structured ceramic media block's attributes allow for a larger process flow velocity through the heat recovery bed with a much smaller space footprint.(RTO) auto thermal conditions and be self-sustaining. Under these conditions, no burner would be required. Once the heat exchange media is saturated and hot enough to elevate the airstream above self-ignition levels, the burner is turned off and combustion blower runs at a minimum position. Natural gas or methane is safely injected into the incoming airstream, enriching it to levels necessary for self-sustaining operation.
Larger abatement capacity can be acheived by greater heat recover chamber velosity through the existing regenerative thermal oxidizer equipment. Utility consumption is higher on older heat recovery beds with saddle configurations due to the pressure drop. Â
Replacement of an ceramic saddle heat recovery bed with more efficient ceramic monolith can purportedly not only reduce the pressure drop across the heat recovery chamber for existing capacity, but provides almost a 40% increase in process stream flow capacities with the existing motor and fan assemblies.
The Burners Go Off
On standard regenerative thermal oxidizers, a fuel burner provides the elevate heat required for destruction. This latent heat amount is the difference that is not trapped within the "HRC" heat recovery bed. This amount is around 5%. However, if the process stream high enough VOC levels the hydrocarbons would provide enough energy for
Auto thermal conditions improves the thermal efficiency of an regenerative thermal oxidizer by decreasing the need for large amounts of combustion air being produced, which mitigates any imbalance in process flow between the two heat recovery beds. Â
Burners are the largest contributor to the formation of NOx by running the system at or closer to the auto-thermal state an improvement in NOx emissions will occur by reducing the high flame temperatures. New low NOx burners reduce much of these emissions. By reducing or shutting off the burner a shape decrease in NOx formation will occur.
The Solution
It is important to understand and examine the plant process stream and the waste constitutes. In applying the correct technology, investigate both the waste stream and process to be abated. Carefully review current and any future regulations, then consider local regulations, space, utility costs to select the correct plant solution.