Paint Spray Booth Research Articles

Toluene and Heavy Metals in Small Automotive Refinishing Shops and Personal Protection of the Workers in Nakhon Si Thammarat, Thailand.

Chemical contamination and safe work practices of workers in automotive refinishing shops have been extensively studied in industrialized countries, but the evidence in developing countries is limited. This study aimed to evaluate chemical contamination and the use of personal protective equipment (PPE) of workers in local small-scale automotive refinishing shops in Nakhon Si Thammarat, Thailand. Airborne toluene and heavy metals, i.e., lead, chromium, and cadmium, were measured in 3 automotive refinishing shops. Toluene exposure assessed by urinary hippuric acid (n = 27) and metal contamination on workers' hands (n = 24) were also determined. Information on the use of PPE and personal hygiene practices of the workers was collected by questionnaires. Average ambient levels of toluene (0.04–18.26 ppm) and the metals (Pb: ND-26.34, Cr: 0.02–4.46, and Cd: ND-1.44 µg/m3) in all sites did not exceed the national standard levels of 200 ppm for toluene (1998) and 50, 12, and 5 µg/m3 for Pb, Cr, and Cd, respectively (2017). The mean ambient levels of these chemicals were highest in paint spray booths followed by nonpainting areas and office rooms, respectively. The highest level of urinary hippuric acid (1.13 g/g creatinine) was found in a painter but did not exceed the recommended biological exposure index of 1.6 g/g creatinine (2014). In contrast, the highest levels of lead and chromium detected on the workers' hands were found in body repair technicians. Direct hand contact without using gloves was suggested as a primary cause of metal contamination.

Removal characteristics of paint particles generated from paint spray booths

The objective of this study is to eliminate the tackiness of sticky paint particles occurring in paint booths using calcium hydroxide. It ultimately aims to identify the optimal filtration velocity to determine the optimal operation condition for particle collection in the filter. As the filtration velocity increased further in the range of 0.2–0.5 m/min, the pressure drop increased rapidly, while the cleaning efficiency, overall collection efficiency, and fractional collection efficiency tended to decrease. The filtration velocity for optimal filtration condition was identified to be 0.2 m/min.

油漆絮凝剂在喷漆房循环水处理中的应用

油漆絮凝剂在喷漆房循环水处理中的应用

Preferential purification of oxygenated volatile organic compounds than monoaromatics emitted from paint spray booth and risk attenuation by the integrated decontamination technique

Purification and risk attenuation of mixed oxygenated volatile organic compounds (OVOCs) and monoaromatics (total concentration: 5.8 × 105–1.2 × 106 μg m−3) from a paint spray booth of auto 4S shop were investigated. The applied integrated technique of spray tower (ST) with photocatalysis (PC) displayed 2.5 times higher elimination capacity (EC) to OVOCs (309.9 g m−3 h−1) than monoaromatics (124.5 g m−3 h−1), due to higher synergetic elimination of these two techniques. Specifically, approximately 4.3 times higher amount of OVOCs than monoaromatics was removed by ST, contributing to their two orders of magnitude higher Henry's law constants. Similar EC trend was also observed on PC (774.5 g m−3 h−1 > 518.5 g m−3 h−1). The corresponding quantum chemical calculation revealed more negative adsorption energy of OVOCs (−40.29 kcal mo1−1) than monoaromatics (−33.32 kcal mo1−1) onto the catalyst, resulting in more spontaneous and easy adsorption, enrichment and later degradation. Furthermore, the integrated technique displayed preferential and efficient reduction ability to both acute inhalation and chronic occupational exposure risks of OVOCs than monoaromatics. This study provided an efficient and pertinent approach to atmospheric purification and human health protection in motorvehicle repair business.

PPG counts on chemistry to give it an edge

About 20 minutes from PPG Industries’ headquarters in downtown Pittsburgh is the Allison Park Coatings Innovation Center. Set on 175 rolling wooded acres, the glass-clad research facility employs more than 280 synthetic chemists, analytical chemists, formulation experts, and chemical engineers. First opened in 1974, the facility just got a $7.8 million upgrade. The project added robotic paint spray booths that replicate customer manufacturing conditions along with new synthesis labs and equipment to accommodate a growing workforce. “We hired 45 Ph.D.s just in the last five years,” says David Bem, PPG’s chief technology officer. More researchers will be coming to the site soon. In the coming years, he says, the firm plans to hire additional chemists, including those with B.S. and M.S. degrees, as it advances work on new types of coatings. The Allison Park researchers are at the vanguard of a global technology force of 3,500 intended to give PPG

Energy Consumption Modeling and Analyses in Automotive Manufacturing Plant

Manufacturing plants energy consumption accounts for a large share in world energy usage. Energy consumption modeling and analyses are widely studied to understand how and where the energy is used inside of the plants. However, a systematic energy modeling approach is seldom studied to describe the holistic energy in the plants. Especially using layers of models to share information and guide the next step modeling is rarely studied. In this paper, a manufacturing system temporal and organizational framework was used to guide the systematic energy modeling approach. Various levels of models were established and tested in an automotive manufacturing plant to illustrate how the approach can be implemented. A detail paint spray booth air unit was described to demonstrate how to investigate the most sensitive variables in affecting energy consumption. While considering the current plant metering status, the proposed approach is advanced in information sharing and improvement suggestion determination.

Preliminary analysis of heat recovery efficiency decrease in paint spray booths

Increasingly the market offers new and used equipment spray booths with cross-recuperators. An attempt is made here to model the heat recovery efficiency decrease in spray booths and a preliminary theoretical analysis is presented. The heat recovery reduction is due to overspray particles deposited within the extraction ducts and heat exchanger walls. The average filtration efficiency degree of the paint stop filters is 93–97%. Filters do not provide complete cleaning of the air from the overspray particles and the growing sediment layer on the recuperator walls is a good thermal insulator. Studies of the deposit layer formation intensity and its thermal conductivity are ongoing.

Preliminary sizing of VOC emission control systems for paint booths

When it is necessary to install a VOC emission control system on a paint spraybooth, "What are the size and weight of the system?" and "What are its utility requirements?" are critical questions that must be answered quickly. The installation costs of the VOC emission control system depend upon its size and weight, and operating costs depend upon the system utility requirements. Methods of quickly estimating the VOC emission control system preliminary size, weight, and utility requirements are, therefore, valuable tools for anyone contemplating installing such a system. The following guidelines will allow almost anyone to roughly estimate size, weight, and utility requirements for some of the commonly employed VOC emission control technologies. These preliminary estimates are believed to be accurate to within 25% of actual values and are solely designed for preparation of initial engineering and management reports. They are not recommended as final installation engineering design values for actual projects.

Performance of a Pilot-Scale Biotrickling Filter in Controlling the Volatile Organic Compound Emissions in a Furniture Manufacturing Facility

A 0.75-m3 pilot-scale biotrickling filter was run for over 1 yr in a Spanish furniture company to evaluate its performance in the removal of volatile organic compounds (VOCs) contained in the emission of two different paint spray booths. The first one was an open front booth used to manually paint furniture, and the second focus was an automatically operated closed booth operated to paint pieces of furniture. In both cases, the VOC emissions were very irregular, with rapid and extreme fluctuations. The pilot plant was operated at an empty bed residence time (EBRT) ranging from 10 to 40 sec, and good removal efficiencies of VOCs were usually obtained. When a buffering activated carbon prefllter was installed, the system performance was improved considerably, so a much better compliance with legal constraints was reached. After different shutdowns in the factory, the period to recover the previous performance of the biotrickling reactor was minimal. A weekend dehydration strategy was developed and implemented to control the pressure drop associated with excessive biomass accumulation.

Sub-acute occupational hypersensitivity pneumonitis due to low-level exposure to diisocyanates in a secretary

There is virtually no information in the literature about the exposure levels needed to induce hypersensitivity pneumonitis (HP) by diisocyanates. The present study reports a case of occupational HP due to diisocyanates after low-level exposure. A 53-yr-old female never-smoker developed progressive shortness of breath on exertion, cough, fatigue and flu-like symptoms shortly after she began work as a secretary of a car body repair shop. A diagnosis of HP was made 2 yrs later, based on a restrictive ventilatory defect, a reticulonodular and discrete ground-glass pattern on high-resolution computed tomography, lymphocytosis in bronchoalveolar lavage and specific immunoglobulin G antibodies to diisocyanate human serum albumin conjugates in the patient's serum. The diagnosis was confirmed by recovery after exposure cessation and deterioration after re-exposure. Ambient monitoring revealed air concentrations of different diisocyanate monomers below the detection limit in both the patient's work station and in front of the paint spray booths, with the exception of one measurement that showed 4,4-methylenediphenyl diisocyanate concentrations of 3 microg x m(-3) in front of one booth (corresponding to a total reactive isocyanate group concentration of 1 microg x m(-3)). The present authors conclude that concentrations of diisocyanates far below current exposure limits may induce hypersensitivity pneumonitis in susceptible subjects.

Aerospace and Maritime Finishing

The event commenced with a tour around a new Grit Blast and Paint Facility operated by the above company. Tour guides were BAE System staff members Mr K. Ford and Mr A. Barnard. The facility is of a significant scale servicing large maritime and defence applications such as radars and antenna systems. A wide range of paints conforming to military specifications can be applied. It has separate grit blast and paint spray booths. Each booth is 13 m long by 6 m in width. Height is 4.5 m. Full safety, health and environmental control systems are installed. Recycling is a high priority with grit blasting media and paint solvent being recycled. ‘Tourists’ commented positively on the facility, particularly the high standard of cleanliness and housekeeping.

Sustained Burning of Water-based Paint Sprays

Water-based paints used in automotive paint spray booths are prone to ignition and combustion might occur for these types of paints when finely dispersed in electrostatic spraying. An experimental study accompanied by equilibrium calculations of adiabatic stoichiometric flame temperature ( ad T ) has been conducted to investigate the burning behavior of water-based spray paints. Several spray fire tests have been carried out and the heat release rates of the flames have been measured. To compare the paints burning behavior, acetone has been added at various concentrations for the spray fire tests. The results have been compared against computed ad T values for the paint-acetone mixtures. Elemental compositions of the paints and their heats of combustion have been measured to compute ad T . A critical temperature ( cr ad T , ) at which combustion will not sustain itself is proposed to characterize the water-based paints. Completeness of combustion ( comb η ) of paint-acetone mixture spray fires has also been used to evaluate the burning behavior of the paints. Based on the critical temperature and completeness of combustion, two regimes of combustion have been identified.

Slow Curing of Aliphatic Polyisocyanate Paints in Automotive Refinishing: A Potential Source for Skin Exposure

Two-component, polyurethane paints containing aliphatic isocyanates are widely used in autobody spray painting. Such isocyanates can cause asthma, and skin exposure may be an important route of sensitization and may contribute to the development of isocyanate asthma. Autobody workers are frequently in contact with recently painted, dried auto parts. It is not known how fast the newly painted car surfaces are fully cured, that is, for how long unbound, isocyanate species remain on painted surfaces after initial drying. To address this question, scrap sections of auto bodies were painted and dried by autobody shop painters following regular practice. Routinely used paints were sprayed 23 different times on the parts. Drying was accomplished by baking the part in a paint spray booth by heating it with a heat lamp or air drying in the shop. The 23 sprayed surfaces were sampled at regular time intervals after drying to determine the presence of free NCO groups using the semiquantitative SWYPE technique. Quantitative isocyanate analysis was also performed on two sprayed parts using NIOSH method 5525. Geometric mean curing time of 23 painted surfaces was 56.4 hr (range: 0.8 hrs to 32 days). Unbound isocyanate species of similar composition to the original bulk material remained present on the majority of sampled painted surfaces for up to 120 hours for typical paint formulations and for 1 month for others. The actual curing of polyurethane paints in autobody refinishing can be a slow process. Unbound isocyanates may remain on the surface of painted car parts for prolonged periods (days to weeks) after dried. Such surfaces are an under-recognized potential source of skin exposure to autobody workers.

Treatment of Paint Spray Booth Off-Gases in a Fungal Biofilter

Biological processes, most notably biofilters and biotrickling filters, are increasingly used to remove and biodegrade a wide variety of volatile organic compounds (VOCs) present in gas streams emitted from industrial operations. In the research described herein, a laboratory-scale biofilter was operated for a period of more than 180 days to treat a waste gas comprised of a four-component VOC mixture representative of solvents present in off-gases emitted by painting operations. The biofilter, packed with a cubed polyurethane foam media and initially inoculated with a pure culture of the fungus Cladosporium sphaerospermum, was maintained under acidic conditions throughout the duration of the experiments. The system was supplied with a mixture of n-butyl acetate, methyl ethyl ketone, methyl propyl ketone, and toluene with influent concentrations of 124, 50.5, 174, and 44.6 mgm−3, respectively. The biofilter’s empty bed residence time (EBRT) was varied from 2.0 min to 15 s. When the influent gas stream was properly humidified, the system exhibited stable long-term performance with an average total VOC removal greater than 98% even with an EBRT as low as 15 s. Under the loading condition tested, this corresponds to an average elimination capacity of 92 gm−3h−1. VOC concentration profiles measured along the height of the biofilter revealed a distinct VOC degradation pattern that was observed under all loading conditions tested. Although the column was initially inoculated with only Cladosporium sphaerospermum, several additional species of fungi tentatively identified as Penicillium brevicompactum, Exophiala jenselmei, Fusarium oxysporum, Fusarium nygamai, Talaromyces flavus, and Fonsecaea pedrosi were found growing attached to the packing medium by the end of experiment. Results demonstrate that fungal biofilters can consistently maintain high removal efficiency for paint VOC mixtures over extended periods of operation. The results also indicate that it would be difficult and likely unnecessary to maintain specific species in full-scale fungal biofilters treating paint spray booth emissions.

Size Distribution of Chromate Paint Aerosol Generated in a Bench-Scale Spray Booth

Spray painters are potentially exposed to aerosols containing hexavalent chromium [Cr(VI)] via inhalation of chromate-based paint sprays. Evaluating the particle size distribution of a paint spray aerosol, and the variables that may affect this distribution, is necessary to determine the site and degree of respiratory deposition and the damage that may result from inhaled Cr(VI)-containing paint particles. This study examined the effect of spray gun atomization pressure, aerosol generation source and aerosol aging on the size distribution of chromate-based paint overspray aerosols generated in a bench-scale paint spray booth. The study also determined the effect of particle bounce inside a Marple personal cascade impactor on measured size distributions of paint spray aerosols. Marple personal cascade impactors with a modified inlet were used for sample collection. The data indicated that paint particle bounce did not occur inside the cascade impactors sufficiently to affect size distribution when using uncoated stainless steel or PVC substrate sampling media. A decrease in paint aerosol mass median aerodynamic diameter (MMAD) from 8.2 to 7.0 mum was observed as gun atomization pressure increased from 6 to 10 psi. Overspray aerosols were sampled at two locations in the spray booth. A downstream sampling position simulated the exposure of a worker standing between the painted surface and exhaust, a situation encountered in booths with multiple workers. The measured mean MMAD was 7.2 mum. The distance between the painted surface and sampler was varied to sample oversprays of varying ages between 2.8 and 7.7 s. Age was not a significant factor for determining MMAD. Overspray was sampled at a 90 degrees position to simulate a worker standing in front of the surface being painted with air flowing to the worker's side, a common situation in field applications. The resulting overspray MMAD averaged 5.9 mum. Direct-spray aerosols were sampled at ages from 5.3 to 11.7 s. Overspray and direct-spray results indicated that most of the change in aerosol size distribution occurred between the time the paint aerosol impacted the painted surface and the time the overspray became 2.8 s old. The overall mean MMAD of overspray in the study was 6.4 mum and may have been underestimated due to sampling efficiency biases. If inhaled by a worker, the overspray aerosols evaluated in this study would mostly deposit in the head airways region of the respiratory tract. Paint overspray aerosols contained Cr primarily in the Cr(VI) state.

A pilot‐scale demonstration of a membrane‐based absorption‐ stripping process for removal and recovery of volatile organic compounds

AbstractA new membrane‐based continuous absorption‐stripping process has been developed to separate gas/vapor mixtures, such as volatile organic compounds (VOCs), from a nitrogen/air stream. Two different hollow fiber membrane modules are needed in this process to remove the VOCs. In the first module, VOC‐laden nitrogen/air stream flows through the bore of the hollow fibers. A suitable absorbent liquid with a high solubility for the VOC and essentially no solubility for nitrogen/air is pumped countercurrently over the outside of the fibers. This liquid is an inert, nontoxic, and essentially nonvolatile, organic solvent. The VOCs are effectively removed from nitrogen/air to a very low level and are concentrated in the absorbent for recovery, while the absorbent is regenerated by heating and subjecting it to vacuum in a separate hollow fiber membrane module called the stripping module.A pilot‐scale membrane‐based absorption‐stripping unit was located next to a paint spray booth at Robins Air Force Base, Warner Robins, GA. Tests were performed on slip‐streams of real‐time air emissions from scheduled intermittent painting operations, so the concentration of VOC in the exhaust air fluctuated with time. The VOC removal efficiency was determined as a function of the feed air flow rate and the absorbent (silicone oil) flow rate. Depending on the gas/liquid flow rates and the inlet VOC concentration, the process successfully removed as much as 95+% of the VOC present. The experimental results have been compared with theoretical predictions.

Paint spraybooth including a wet scrubber-strip plating device

In this work, we report the performance of a lab scale wet packed-bed scrubber using woodchips as a packing material. Wood chips were wetted by waste cooking oil which acted as a scrubber medium. Residence time of 8.5 s was comparable to the packed-bed filter used in a pilot scale gasifier. We studied the effects of oil/gas ratio (4.7 and 7 m3/s/m3/s × 103), oil temperature (ambient, ~23 °C and 50 °C) and woodchips size (coarse = ~0.02–0.045 m, 0.003–0.03 m and 0.002–0.007 m and fine = (0.015–0.04 m) × (0.002–0.005 m) × (0.001–0.003 m)) to remove tar model compounds from producer gas. The results demonstrate liquid to gas ratio has significant effect (p-value = 0.002) on removing toluene as tar model compound; next important parameter is bed configuration (p-value = 0.014), impacting toluene removal efficiency. For naphthalene, oil flow rate (p-value = 0.022) and bed configuration (p-value = 0.024) have almost similar effects. Oil temperature has relatively lower impact on removing tar.

Treating paint spraybooth water

Treating paint spraybooth water

Preliminary sizing of voc emission control systems for paint booths

When it is necessary to install a VOC emission control system on a paint spraybooth, What are the size and weight of the system? and What are its utility requirements? are critical questions that must be answered quickly. The installation costs of the VOC emission control system depend upon its size and weight, and operating costs depend upon the system utility requirements. Methods of quickly estimating the VOC emission control system preliminary size, weight, and utility requirements are, therefore, valuable tools for anyone contemplating installing such a system. The following guidelines will allow almost anyone to roughly estimate size, weight, and utility requirements for some of the commonly employed VOC emission control technologies. These preliminary estimates are believed to be accurate to within 25% of actual values and are solely designed for preparation of initial engineering and management reports. They are not recommended as final installation engineering design values for actual projects.

Fundamentals of paint spraybooth lighting

Fundamentals of paint spraybooth lighting