Exhaust Air Stream Research Articles

Experimental study on pressure loss and collection efficiency of drift eliminators

Drift eliminators play a major role in cooling tower operation. They are designed to reduce the discharge aerosols in their exhaust air stream to a minimum since inhaled airborne particles can cause the well-known Legionnaires disease. However, the pressure drop induced into the air stream increases the power consumption of the system. Accordingly, the design and selection of these elements should be a trade-off between the pressure drop and the collection efficiency. In this paper, six commercial drift eliminators (vane, wire mesh, and honeycomb-type) have been characterized in terms of pressure drop and collection efficiency with the aim of providing reliable information that can be used in drift eliminator design and selection. Fifty-three experiments were conducted regarding the pressure drop and collection efficiency characterization of the eliminators. Generally speaking, for the same type of eliminators the higher the pressure drop, the more efficient it is. Concerning typologies, wire-mesh eliminators perform better than the rest in terms of both pressure drop and collection efficiency. Dimensionless correlations for the pressure drop coefficient and the collection efficiency have been developed for the tested eliminators, showing a good agreement with the experimental results. A selection criterion has been proposed based on the dimensionless parameters that govern the problem and the experimental data of power consumption. It is based on determining the power consumed by the fans of the tower by setting a limit of collection efficiency and the droplet distribution characteristics at the cooling tower outlet area.

REVERSIBLE VENTILATION SYSTEM FOR ADMINISTRATIVE BUILDINGS

Objectives To consider the possibility of applying the principle of reversing air flows for a centralised ventilation system; to develop a specific scheme for air exchange reversible ventilation, which will take into account the peculiarities of the microclimate of administrative buildings; to select the type of filling of the air-permeable element and justify this choice; to determine the conditions for changing the direction of air movement in the ventilation system and the area of its application; to form a list of equipment necessary for the operation of such a system; to consider the influence of supply and exhaust devices on the heat and humidity regime of claddings. Methods To achieve this goal, the published thematic material was reviewed and a patent search carried out using Russian and European databases. Data on mathematical modelling of filtration in porous media and experimental results were used. A method for ventilating rooms in administrative building using the reversal of movement of supply and exhaust air streams along the same channels was applied. Results Schemas for reversible ventilation systems are presented and their modes of operation considered. It is established that the idea of reversing ventilation flows has not yet been applied in the development of centralised ventilation systems. Based on these published materials, it was concluded that the proposed design of supply and exhaust devices can be used in practice. An original air exchange scheme for the ventilation of administrative buildings and design of supply and exhaust devices for this system are proposed. The conditions for changing the operating modes of the system and the scope of its application are determined. Conclusion The use of the proposed ventilation system allows normative air exchange to be provided without using a supply unit during the cold season. This application of airflow reversal allows the potential of natural forces to be used to the fullest extent to ensure the air exchange of the rooms.

Experimental investigation of carbon dioxide cross-contamination in sorption energy recovery wheel in ventilation system

The aim of this research was to investigate the scale of carbon dioxide recirculation in rotary energy wheel operated in air handling units. To achieve this objective, a test facility was installed into the indoor air quality and thermal comfort laboratory of BUTE University. A newly developed molecular 3 Å sieve sorption wheel with high humidity transfer efficiencies is integrated into the experimental setup. In this research study, carbon dioxide cross-contamination rate from the exhaust side into the supply side in sorption regenerative air-to-air rotary energy exchanger was conducted by experimental tests. During the study, the correlation between the carbon dioxide cross-contamination, different rotational speeds of the wheel and different volume flow rates of supply air were also investigated in detail. Based on the results, a rotation speed diagram – carbon dioxide cross-contamination diagram – is plotted which can be very useful for researchers, developers and building service engineers in practice. Practical application: The most perfect energy exchanger can transfer both heat and moisture, thus providing a pleasant indoor air quality in the conditioned space. It is beneficial if the exchanger can transfer heat and moisture between the supply and exhaust airstreams, thereby minimizing the capacity and energy consumption of the required auxiliary heater and humidifier. The auxiliary energy reduction can be especially high if the sorption material of the energy wheel is of type 3 Å molecular sieve that has an extremely high humidity transfer capacity. The disadvantage of the rotary energy recovery is the cross-contamination from the exhaust air to the supply air. This is very important because in places such as offices, schools, public institutions, carbon dioxide cross-contamination can cause degradation of indoor air quality.

Trace Adsorption of Ethane, Propane, and n-Butane on Microporous Activated Carbon and Zeolite 13X at Low Temperatures

Removing of trace-leveled light hydrocarbons from exhaust air or gas streams becomes an increasingly important issue in the field of process and environmental technology, e.g., storage and transport of liquefied natural gas. Adsorption processes at temperatures below 0 °C have great potential to meet process specifications or environmental regulatory limits. Designing of such adsorption processes requires a profound insight into the thermodynamics of adsorption at low temperatures, which is not available yet. Therefore, this work provides adsorption isotherms of ethane, propane, and n-butane on microporous activated carbon and zeolite 13X in a temperature range from −40 to +60 °C and at partial pressures from 5 to 1000 Pa. The influence of temperature on the adsorbed amount on activated carbon and zeolite 13X is discussed for each adsorptive considering isosteric heats of adsorption and specific interactions between the adsorptive and the adsorbent surface.

Investigation of energy recovery with exhaust air evaporative cooling in ventilation system

Building ventilation is mandatory to provide occupants with comfort space. This ventilated air is considered as a waste of energy because the fresh air will enter the room at higher or lower temperature than the room temperature in summer and winter seasons. Moreover, as much as the temperature of fresh air is reduced, lower cooling load is needed. This will lead to reduce the capacity and the power consumption of HVAC system. Normally, energy recovery is used for this purpose. On the other hand, an additional cooling method (evaporative cooling unit) can be added to the exhaust air stream from the energy recovery to reduce its temperature and correspondingly reduce the fresh air temperature. In this research, a model of Energy Recovery with Exhaust air Evaporative Cooling (EREEC) in ventilation is built to test the thermal performance theoretically and experimentally in Mediterranean climate. The results indicated a superior saving due to using EREEC. The inlet temperature is reduced by 2.2°C at ambient temperature of 24.4°C and by 7.5°C at highest ambient temperature of 35.7°C. Additionally, simulation results show that the base cooling load can be reduced up to 13.38%. Moreover, the Payback Period of EREEC from annual energy saving occurred is around 8 years.

Impact of damper opening time on work of storage matrix regenerative heat exchanger

Devices that by heat exchange take heat from exhaust air stream and transfer it to the external air stream in order to pre heat are called heat recovery heat exchangers. The heat exchange may take place through the wall (diaphragm) or using heat storage liquid (these devices are called recuperators) or by direct contact of exhaust and external air stream with the heat transfer surface - these devices are called regenerators. The publication presents the work characteristics of the storage matrix heat exchanger based on laboratory tests. In order to achieve the objectives the research station was designed and built.

Study of Dehumidification and Regeneration in a Starch Coated Energy Wheel

Energy wheels were designed using desiccant-coated materials to exchange energy between supply and exhaust air streams to reduce the energy required to condition ventilation air. Recent advances in energy wheel design that use biopolymer desiccant materials have provided the motivation in this paper to investigate the performance of starch coated energy exchangers. A small-scale high amylose starch (HAS) coated exchanger was built, and its transient response to a step change in inlet humidity was acquired and studied at conditions of variable air flow rate and temperature. The humidity response, dehumidification, regeneration capacity, and the rate of moisture removal were measured. The results demonstrate that greater regeneration flow rate and temperature can enhance the regeneration capacity. In spite of the increase in the regeneration capacity, the moisture recovery (latent) effectiveness decreased as the air flow rate and/or temperature increased. The effectiveness is reduced by 15% when the flow ra...

Performance of a Thermally Coupled Hydrogen Storage and Fuel Cell System Under Different Operation Conditions

The performance of a hydrogen storage prototype loaded with AB5H6 hydride, whose equilibrium pressure makes it suitable for both feeding a H2/air proton exchange membrane (PEM) fuel cell and being charged directly from a low-pressure water electrolyzer, interacting thermally with the fuel cell exhaust air, is reported. The nominal 70 L hydrogen storage capacity of the prototype suffices for hydrogen delivery at 0.5 L min−1, which allows a power supply of 50 W for 140 min from the H2/air fuel cell in the absence of thermal interaction. The storage prototype was characterized by monitoring the internal pressure and the temperatures of the external wall and at the center inside the container at different hydrogen discharge conditions. The responses of the integrated system after either immersing the metal hydride container in air or exposing it to the fuel cell hot exhaust air stream under forced convection were compared. The system shows the best performance when the heat generated at the fuel cell is used to increase the metal hydride container temperature, allowing the operation of the fuel cell at 280 W for 16 min at a high hydrogen flow rate of 4 L min−1.

Appropriate placement of vapour recompression in ultra-low energy industrial milk evaporation systems using Pinch Analysis

This study focuses on applying Pinch Analysis to an industrial milk evaporator case study to quantify the potential energy savings. Modern milk evaporators are typically integrated using both mechanical and thermal vapour recompression technologies as the primary means for attaining a high level of energy efficiency. A significant step change in energy efficiency for milk evaporators is achieved in this study by appropriate placement of vapour recompression in a new improved two-effect milk evaporation system design. The Grand Composite Curve helps identify areas for process modifications and placements of vapour recompression that result in energy reduction. In particular, the innovative placement of Mechanical Vapour Recompression in the system unlocks significant energy, energy cost, and emissions savings. The new design requires 78% less steam (6397 kW) at the expense of 16% (364 kWele) more electricity use. The estimated cost savings associated with the improved design is $942,601/y and the emissions reduction is 3416 t CO2-e/y. Further energy efficiency improvements and cost savings of $1,411,844/y are gained through improved Total Site Heat Integration through recovery of waste heat from the dryer exhaust air and boiler return condensate streams.

Effects of Heat Loss/Gain on the Transient Testing of Heat Wheels

Heat wheels are used in ventilation systems to provide indoor thermal comfort by recovering considerable amount of sensible energy from exhaust airstream. The transient single step test is a new testing method developed to determine the sensible effectiveness of heat wheels. In practice, heat loss/gain may create large uncertainty in the sensible effectiveness obtained through the transient testing. In this study, the transient analytical model in the literature is extended to account for heat loss/gain effects in the transient testing. The results state that in particular operating conditions, the sensible effectiveness can be affected by more than 10% due to heat loss/gain. A new testing facility is developed to investigate the effects of heat loss/gain on the sensible effectiveness through transient testing of a small-scale heat exchanger. After decoupling heat loss/gain effects from transient test data, less than 2% difference was observed in the sensible effectiveness while supply and exhaust flow rate was small (Re < 209) and the temperature difference between them was ΔTst < 7.0 °C. However, the sensible effectiveness decreased more than 9% while ΔTst > 37.5 °C or Re > 600. An empirical correlation was proposed based on the transient test data that correlates the sensible effectiveness with the heat capacity rate ratio. Comparing the results of proposed correlation with literature, less than 2% difference was observed at the heat capacity rate ratio of greater than 0.5 after the heat loss/gain effects were decoupled from transient test data.

The application of linear regression and the power law relationship of air-side heat transfer with field measurements to model the performance of run-around heat recovery systems

Improving the performance of air-to-air heat recovery systems, as measured by supply air temperature efficiency, is an important energy saving strategy that is often regulated by building codes. The high nonlinearity of supply air temperature efficiency with airflow rate in a run-around heat recovery system makes the trend prediction of supply air temperature efficiency especially challenging for field measurement. This paper proposes a simple and novel field measurement based methodology, supported by the power law relationship of air-side heat transfer, to evaluate the performance of run-around heat recovery systems. A system dependent power, signature power, is proposed that establishes a linear relationship between the supply air temperature increment across the supply air heat exchanger and a parameter—the maximum temperature difference between exhaust and supply airstreams divided by the signature power of the supply airflow rate. This methodology can predict the supply air temperature efficiency and is verified using four run-around heat recovery systems with field measurements. This new methodology can possibly be applied to other types of air-to-air heat recovery systems. This paper also describes a tuning method for determining the signature power based on field measurements and addresses the heat recovery efficiency of run-around heat recovery systems.

Modelling heat and mass transfer in a membrane-based air-to-air enthalpy exchanger

The diffusion of total energy recovery systems could lead to a significant reduction in the energy demand for building air-conditioning. With these devices, sensible heat and humidity can be recovered in winter from the exhaust airstream, while, in summer, the incoming air stream can be cooled and dehumidified by transferring the excess heat and moisture to the exhaust air stream. Membrane based enthalpy exchangers are composed by different channels separated by semi-permeable membranes. The membrane allows moisture transfer under vapour pressure difference, or water concentration difference, between the two sides and, at the same time, it is ideally impermeable to air and other contaminants present in exhaust air. Heat transfer between the airstreams occurs through the membrane due to the temperature gradient. The aim of this work is to develop a detailed model of the coupled heat and mass transfer mechanisms through the membrane between the two airstreams. After a review of the most relevant models published in the scientific literature, the governing equations are presented and some simplifying assumptions are analysed and discussed. As a result, a steady-state, two-dimensional finite difference numerical model is setup. The developed model is able to predict temperature and humidity evolution inside the channels. Sensible and latent heat transfer rate, as well as moisture transfer rate, are determined. A sensitive analysis is conducted in order to determine the more influential parameters on the thermal and vapour transfer.

Conjugate heat and mass transfer in a total heat exchanger with cross-corrugated triangular ducts and one-step made asymmetric membranes

Membrane-based total heat exchanger is a device to recover both sensible heat and moisture from exhaust air stream from a building. Heat and mass transfer intensification has been undertaken by using a structure of cross-corrugated triangular ducts. To further intensify moisture transfer, recently developed membranes-one step made asymmetric membranes, are used as the exchanger materials. Conjugate heat and mass transfer under transitional flow regime in this total heat exchanger are investigated. Contrary to the traditional methods of assuming a uniform temperature (concentration) or a uniform heat flux (mass flux) boundary condition, in this study, the real boundary conditions on the exchanger surfaces are obtained by the numerical solution of the coupled equations that govern the transfer of momentum, energy and moisture in the two air streams and in the membrane materials. The naturally formed heat and mass boundary conditions are then used to calculate the local and mean Nusselt and Sherwood numbers along the exchanger ducts, in the heat and mass developing regions. The data are compared with those results under uniform temperature (concentration) and uniform heat flux (mass flux) boundary conditions, for cross-corrugated triangular ducts with typical duct apex angles of 60° and 90°.

Performance investigation of liquid-to-air membrane energy exchanger under low solution/air heat capacity rates ratio conditions

Liquid-to-air membrane energy exchanger is a novel membrane base energy exchanger, which allows both heat and moisture transfer between air and a salt solution. The heat and mass transfer performance of a single one is significantly dependent on two dimensionless parameters: number of heat transfer units and the ratio of heat capacity rates between solution flow and air flow (Cr*). The performance of liquid-to-air membrane energy exchanger under high Cr* (i.e. Cr* ≥ 1) has been comprehensively investigated experimentally and numerically in previous research. In this study, the effectiveness of a small-scale liquid-to-air membrane energy exchanger under low Cr* conditions (i.e. Cr* < 1) is experimentally tested. Good agreement between the experimental and numerical results is achieved under low Cr* cases. Practical application: The ideal energy exchanger is one that can transfer both heat and moisture because during hot and humid conditions such an exchanger is capable of transferring up to four times as much energy as an exchanger that can transfer sensible heat only. It is beneficial if the exchanger can transfer heat and moisture also between remote supply and exhaust airstreams, as this may minimize the ducting required and reduces contaminant transfer from one airstream to the other. This is very important for applications such as hospitals, laboratories, and manufacturing facilities, where slight cross contamination can cause serious health effects.

First Stage Lint Cleaning Systems Emission Factors and Rates for Cotton Gins: Method 201A PM10 Sizing Cyclones

This report is part of a project to characterize cotton gin emissions from the standpoint of stack sampling. The impetus behind this project was the urgent need to collect cotton gin emissions data to address current regulatory issues. A key component of this study was focused on EPA emission factors for particulate matter with a particle diameter nominally less than or equal to 10 µm (PM10). The 1996 EPA AP-42 emission factors were assigned quality ratings, from A (Excellent) to E (Poor), to assess the quality of the data being referenced. Emission factor quality ratings for cotton gins were extremely low. Also, some commonly used cotton gin systems were not represented or were combined with another system under a single emission factor in AP-42. No EPA AP-42 emission factors were published for 1st stage lint cleaning systems. The objective of this study was to collect PM10 emission factor data for 1st stage lint cleaning systems at cotton gins located in regions across the cotton belt based on EPA-approved stack sampling methodology, Method 201A. The project plan included sampling seven cotton gins across the cotton belt. Key factors for selecting specific cotton gins included: 1) facility location, 2) production capacity, 3) processing systems and 4) abatement technologies. Four of the seven gins were equipped with 1st stage lint cleaning systems where the exhaust airstreams were not combined with 2nd stage lint cleaning systems. In terms of capacity, the four gins were typical of the industry, averaging 28.1 bales/h during testing. Some test runs, included in the analyses, had cotton lint fibers that collected in the ≤ 10 µm samples. This larger lint material can affect the reported emissions data, but EPA Method 201A does not suggest methods to account for these anomalies. The 1st stage lint cleaning system average emission factors for PM10 and total particulate were 0.041 kg/227-kg bale (0.091 lb/500-lb bale) and 0.066 kg/bale (0.146 lb/bale), respectively. System average PM10 and total particulate emission factors were lower than those currently published in EPA AP-42 for 1st and 2nd stage lint cleaning systems combined. The 1st stage lint cleaning system PM10 emission rate test averages ranged from 0.26 to 2.92 kg/h (0.58-6.44 lb/h). The ratio of 1st stage lint cleaning system PM10 to total particulate was 62.3%.

Combined Lint Cleaning System PM10 Emission Factors and Rates for Cotton Gins: Method 201A PM10 Sizing Cyclones

This report is part of a project to characterize cotton gin emissions from the standpoint of stack sampling. The impetus behind this project was the urgent need to collect additional cotton gin emissions data to address current regulatory issues. A key component of this study was focused on EPA emission factors for particulate matter with a particle diameter nominally less than or equal to 10 µm (PM10). The 1996 EPA AP-42 emission factors were assigned quality ratings, from A (Excellent) to E (Poor), to assess the quality of the data being referenced. Emission factor quality ratings for cotton gins were extremely low. Cotton gin data received these low ratings because they were collected almost exclusively from a single geographical region. The objective of this study was to collect additional PM10 emission factor data for combined lint cleaning systems at cotton gins located in regions across the cotton belt based on EPA-approved stack sampling methodology, Method 201A. The project plan included sampling seven cotton gins across the cotton belt. Key factors for selecting specific cotton gins included: 1) facility location, 2) production capacity, 3) processing systems and 4) abatement technologies. Three of the seven gins had 1st and 2nd stage lint cleaning systems where the exhaust airstreams were combined. In terms of capacity, the three gins were typical of the industry, averaging 28.0 bales/h during testing. Some test runs, included in the analyses, had cotton lint fibers that collected in the ≤ 10 µm samples. This larger lint material can affect the reported emissions data, but EPA Method 201A does not suggest methods to account for these anomalies. The combined lint cleaning system average emission factors for PM10 and total particulate were 0.150 kg/227-kg bale (0.332 lb/500-lb bale) and 0.293 kg/bale (0.647 lb/bale), respectively. System average PM10 and total particulate emission factors were higher than those currently published in EPA AP-42. The combined lint cleaning system PM10 emission rate test averages ranged from 1.62 to 5.19 kg/h (3.56-11.45 lb/h). The ratio of combined lint cleaning system PM10 to total particulate was 51.3%.

Mote Trash System PM10 Emission Factors and Rates for Cotton Gins: Method 201A PM10 Sizing Cyclones

This report is part of a project to characterize cotton gin emissions from the standpoint of stack sampling. The impetus behind this project was the urgent need to collect additional cotton gin emissions data to address current regulatory issues. A key component of this study was focused on EPA emission factors for particulate matter with a particle diameter nominally less than or equal to 10 µm (PM10). The 1996 EPA AP-42 emission factors were assigned quality ratings, from A (Excellent) to E (Poor), to assess the quality of the data being referenced. Emission factor quality ratings for cotton gins were extremely low. Cotton gin data received these low ratings because they were collected almost exclusively from a single geographical region. The objective of this study was to collect additional PM10 emission factor data for mote trash systems at cotton gins located in regions across the cotton belt based on EPA-approved stack sampling methodology, Method 201A. The project plan included sampling seven cotton gins across the cotton belt. Key factors for selecting specific cotton gins included: 1) facility location, 2) production capacity, 3) processing systems, and 4) abatement technologies. Two of the seven gins had mote trash systems where the exhaust airstreams were not combined with other major systems. In terms of capacity, the two gins were typical of the industry, averaging 32.4 bales/h during testing. The mote trash system average emission factors for PM10 and total particulate were 0.011 kg/227-kg bale (0.025 lb/500-lb bale) and 0.021 kg/bale (0.046 lb/bale), respectively. The system average PM10 emission factor was higher and the system average total particulate emission factor was lower than those currently published in EPA AP-42. Mote trash system PM10 emission rate test averages ranged from 0.32 to 0.37 kg/h (0.72-0.81 lb/h). The ratio of mote trash system PM10 to total particulate was 53.2%.

Unloading System PM10 Emission Factors and Rates for Cotton Gins: Method 201A PM10 Sizing Cyclones

This report is part of a project to characterize cotton gin emissions from the standpoint of stack sampling. The impetus behind this project was the urgent need to collect additional cotton gin emissions data to address current regulatory issues. A key component of this study was focused on EPA emission factors for particulate matter with a particle diameter nominally less than or equal to 10 µm (PM10). The 1996 EPA AP-42 emission factors were assigned quality ratings, from A (Excellent) to E (Poor), to assess the quality of the data being referenced. Emission factor quality ratings for cotton gins were extremely low. Cotton gin data received these low ratings because they were collected almost exclusively from a single geographical region. The objective of this study was to collect additional PM10 emission factor data for unloading systems at cotton gins located in regions across the cotton belt based on EPA-approved stack sampling methodology, Method 201A. The project plan included sampling seven cotton gins across the cotton belt. Key factors for selecting specific cotton gins included: 1) facility location, 2) production capacity, 3) processing systems and 4) abatement technologies. Three of the seven gins had unloading systems that used pneumatic conveyance and had exhaust airstreams that were not combined with another system. In terms of capacity, the three gins were typical of the industry, averaging 26.1 bales/h during testing. Some test runs were excluded from the test averages because they failed to meet EPA Method 201A test criteria. Also, other test runs, included in the analyses, had cotton lint fibers that collected in the ≤ 10 µm samples. This larger lint material can affect the reported emissions data, but EPA Method 201A does not suggest methods to account for these anomalies. The unloading system average emission factors for PM10 and total particulate were 0.107 kg/227-kg bale (0.237 lb/500-lb bale) and 0.131 kg/bale (0.289 lb/bale), respectively. The system average PM10 emission factor was higher and the system average total particulate emission factor was about the same as those currently published in EPA AP-42. Unloading system PM10 emission rate test averages ranged from 1.16 to 3.99 kg/h (2.57-8.79 lb/h). The ratio of unloading system PM10 to total particulate was 81.9%.

Second Stage Lint Cleaning System PM10 Emission Factors and Rates for Cotton Gins: Method 201A PM10 Sizing Cyclones

This report is part of a project to characterize cotton gin emissions from the standpoint of stack sampling. The impetus behind this project was the urgent need to collect cotton gin emissions data to address current regulatory issues. A key component of this study was focused on Environmental Protection Agency (EPA) emission factors for particulate matter with a particle diameter nominally less than or equal to 10 µm (PM10). The 1996 EPA AP-42 emission factors were assigned quality ratings, from A (Excellent) to E (Poor), to assess the quality of the data being referenced. Emission factor quality ratings for cotton gins were extremely low. Also, some commonly used cotton gin systems were not represented or were combined with another system under a single emission factor in AP-42. There were no 1996 EPA AP-42 emission factors published for 2nd stage lint cleaning systems. The objective of this study was to collect PM10 emission factor data for 2nd stage lint cleaning systems at cotton gins located in regions across the cotton belt based on EPA-approved stack sampling methodology, Method 201A. The project plan included sampling seven cotton gins across the cotton belt. Key factors for selecting specific cotton gins included: 1) facility location, 2) production capacity, 3) processing systems and 4) abatement technologies. Four of the seven gins were equipped with 2nd stage lint cleaning systems where the exhaust airstreams were not combined with the 1st stage lint cleaning systems. In terms of capacity, the four gins were typical of the industry, averaging 29.4 bales/h during testing. Some test runs were excluded from the test averages because they failed to meet EPA Method 201A test criteria. Also, other test runs, included in the analyses, had cotton lint fibers that collected in the ≤ 10 µm samples. This larger lint material can affect the reported emissions data, but EPA Method 201A does not suggest methods to account for these anomalies. The 2nd stage lint cleaning system average emission factors for PM10 and total particulate were 0.018 kg/227-kg bale (0.039 lb/500-lb bale) and 0.035 kg/bale (0.078 lb/bale), respectively. System average PM10 and total particulate emission factors were lower than those currently published in EPA AP-42 for 1st and 2nd stage lint cleaning systems combined. The 2nd stage lint cleaning system PM10 emission rate test averages ranged from 0.15 to 0.98 kg/h (0.33-2.17 lb/h). The ratio of 2nd stage lint cleaning system PM10 to total particulate was 50.5%.

Combined Mote System PM10 Emission Factors and Rates for Cotton Gins: Hope Method 201A PM10 Sizing Cyclones

This report is part of a project to characterize cotton gin emissions from the standpoint of stack sampling. The impetus behind this project was the urgent need to collect additional cotton gin emissions data to address current regulatory issues. A key component of this study was focused on EPA emission factors for particulate matter with a particle diameter nominally less than or equal to 10 µm (PM10). The 1996 EPA AP-42 emission factors were assigned quality ratings, from A (Excellent) to E (Poor), to assess the quality of the data being referenced. Emission factor quality ratings for cotton gins were extremely low. Cotton gin data received these low ratings because they were collected almost exclusively from a single geographical region. The objective of this study was to collect additional PM10 emission factor data for combined mote systems at cotton gins located in regions across the cotton belt based on EPA-approved stack sampling methodology, Method 201A. The project plan included sampling seven cotton gins across the cotton belt. Key factors for selecting specific cotton gins included: 1) facility location, 2) production capacity, 3) processing systems, and 4) abatement technologies. Two of the seven gins were equipped with combined mote systems where the 1st and 2nd stage mote system exhaust airstreams were combined. In terms of capacity, the two gins were typical of the industry, averaging 35.1 bales/h during testing. The combined mote system average emission factors for PM10 and total particulate were 0.098 kg/227-kg bale (0.215 lb/500-lb bale) and 0.141 kg/bale (0.310 lb/bale), respectively. System average PM10 and total particulate emission factors were higher than those currently published in EPA AP-42. The combined mote system PM10 emission rate test averages ranged from 2.57 to 4.28 kg/h (5.66-9.44 lb/h). The ratio of combined mote system PM10 to total particulate was 69.3%.