الفهرس 
SUBJECTS AND METHODSOnly 14 pages are availabe for public view
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Abstract
Fertilizers play a fundamental role in replenishing the nutrients that the plant gets from the soil and necessary for its growth. As a result of the population increase, there is an increase in agricultural crops production and therefore the using various types of fertilizers has been increased.The most important of which are the nitrogenous fertilizers represented in ammonia, urea and ammonium nitrate makingthe nitrogen fertilizer industry as one of the most important modern petrochemical industry in Egypt. Among the challenges that are specific to this industry is the exposure of workers in the work environment to the emission of pollutants, particularly the ammonia gas which has various harmful health, occupational and environmental effects.
Over the past decades, the process of manufacturing of these fertilizers has evolved and the leading companies competed in establishing technologically advanced cleaner production plants to ensure that the emission of ammonia gas in the work environment is reduced.In addition; the health, occupational and environmental limits and standards reduced and occupational exposure and its risks toward workers was controlled. Therefore, it was necessary to study the occupational exposure to ammonia gas in one of the modern companies for the manufacture of nitrogenous fertilizers in Alexandria and to explore the updates of production technologies and manufacturing processes.
Aim of the study
The general objective wasto studythe occupational exposure to ammonia levels in modern modified nitrogenous fertilizer industry in Alexandria, Egypt.The specific objectives were to assess the exposure to ammonia levels in different working locations in a nitrogenous fertilizer industry,monitor the new modification in the occupational environment established in the modern nitrogenous fertilizer plant, investigate possible associations between occupational exposure to ammonia, and health complaints among the employees across the work shift at a fertilizer production plant.
Study subjects and methods
The number of workers participated in the study was168 workers, working in one of the company’s manufacturing nitrogenous fertilizers in Abi Qir area in Alexandria governorate.The selected company is one of the modern companies designed with the most modern methods of constructing and manufacturing global nitrogenous fertilizers. The workers participating in the study represent the various departments in ammonia and urea manufacturing plants, as well as representatives from the morning and evening shifts.
Ammonia gas concentration was also measured in air samples in ten different locations in the company work environment by using a MIRAN IR analyzer direct reading device.
After verbal approval from the participating workers, the data were collected using two forms of interview questionnaire including knowledge about the Demographyof the participating workers, the job title and the department to which the worker belongs, as well as the work shift and years of experience in the job.In addition; the professional profile including the current job position and the period of exposure to ammonia gas and the workers’ use of personal protective equipment in the different work departments and the extent of their knowledge and awareness about the importance of using this equipment and their different types. Furthermore; the health profile including currenthealth profilealong the working years particularly occupational diseases related to the respiratory system andfamily history of illnesses, and smoking behaviors.
A model for measurements of ammonia gas concentration in ten different locations in the company during the study period was fulfilled.Standing on the most important modern technological process used in the manufacture of ammonia and urea, and the cleaner production policies implemented by the company was achieved.
Study results
The current study showed that workers in the nitrogen fertilizer industry are males due to the nature of the environment and work requirements in that industry. The vast majority of workers are technicians in the operation department of the factory.The study showed that the vast majority of the participating workers range from 10 to 15 years of experience in the field of work. The average of working hours is 48 hours per week. As regard to workers’ use of personal protective equipment, the majority of workers 99.4% use personal protective equipment. It was found that 95.8% of workers use gloves and shoes, followed by goggles (88.7%), apron (74.4%), protective suit (73.2%), hat and mask (45.8%, 58.9% respectively) and the lowest percentage for respirator use (38.7%). The higher percentage of workers who use personal protective equipment reflects their increased knowledge and awareness of the importance of using this equipment and its role in preventing potential occupational hazards in the work environment.
The study showed that the measured concentrations of ammonia gas were less than the TLV-TWA adjusted for ammonia gas, and the mean concentrations of ammonia gas in the breathing zone of workers at ammonia plant, the urea plant, the urea granulation, areabetween the ammonia plant and the urea plant and the south area of the plant were (0.81 ± 0.03), (0.95 ± 0.06),( 0.98 ± 0.01), (1.03 ± 0.03), and(1.06 ± 0.02) ppm respectively.The current study reveals that the new plant was constructed by the German company ThyssenKrupp Uhde GmbH, which has a long history of innovation in the ammonia industry. Significant improvements are observed with respect to the dual pressure ammonia manufacturing loopsand the characteristic improved by secondary reformer design applying with swing adsorption pressure system for hydrogen gas recovery and air separation plant as nitrogen gas source.
The current study showed that the reduction in ammonia gas emissions in modern ammonia and urea plants resulted from the use of clean and environmentally friendly manufacturing and production technologies and the implementation of the best available manufacturing technology; such as, wet scrubber and condensate separator to control ammonia emissions showing a control efficiency of 99%, pollution prevention techniques including the recycling of ammonia into the production processand reducing the amount of ammonia or urea used for controlling nitrogen oxides from combustion sources usingselective catalytic (SCR) and non-catalytic reduction (SNCR), andthe various capture devices for ammonia emissions, and implementation of good maintenance practices.
Finally, this study clarified that the modern technologies implemented in the establishment of the modern nitrogen fertilizer plantin Alexandria have largely implemented their goals of efficiency, confidence and continuity to reach an increase in energy efficiency with low emissions of carbon dioxide and reduce occupational exposure to ammonia gas.In addition to; improving Occupational health and safety standards, air quality and raising awareness among workers through training programs to keep up with technological progress and modern applied strategies to improve the factory in terms of occupational health and safety , maintenance and management.
Recommendations
In light of the results of the study, the following recommendations were suggested:
1. A large number of nitrogen fertilizer plants now require development and modernization. This is containing terms of hardware, application, and knowledge of operation and maintenance personnel, by developing smart migration strategies to upgrade old plants to the latest technology. This ensures that the plant operating company can save existing investments in the long run, increase the overall return on capital and eliminate or reduce ammonia emissions and thus reduce the risk of occupational exposure to workers.
2. The basic standards now in ammonia plants are to enhance advanced control process such asdistributed control systems (DCSs) andsafetyinstrumented systems (SIS). Prior to the start of the plant operation, Hazard and Operational Studies (HAZOP) and Protection Layer Analyzes (LOPAs) are required for safe workplaces and occupational health improvement for workers in the nitrogenous fertilizer industries. As well as using the latest training courses and appropriate education programs to guarantee that engineers and operators can achieve their duties safely and efficiently.
3. Further studies are required to assess the improvements made to these technologies in the nitrogenous fertilizer industries and the impact of occupational exposure risks on workers’ health. On the production aspect, the developing of industrial technologies for fully producing ”green ammonia” from sustainable and carbonneutral inputs, such as renewable electricity and biomass that need more surveys. Additionally, these studies could include a number of experimental projects, which are presently underway such as a focus nextgeneration technologies that may in the future lead to the low-cost production of carbon-neutral nitrogen fertilizers.
6.2 Conclusion
Based on the finding of the present study, it can be concluded:
1. The studied sample was males, 75.6% of workers worked as technicians and 24.4% as engineers;Where, more one than half of the workers have a work of duration between 10-15 years. In addition, 54.8% of the workers were in operation department, 18.5 % in production department and 26.8% in maintenance, inspection department. More than two-thirds (70.8%) of participants are day shift workers.
2. The majority of participant current work duties are operation technicians (45.8%) followed by operation engineers (19.6%).
3. The majority of the workers (99.4%) are using different types of personal protective equipment (PPE), which reflects the increase in their knowledge and awareness about the importance of using this equipment and adequate awareness of safety roles in prevention from the possible potential occupational hazards in the work environment.
4. The highest percentage of participants (95.8%) are using gloves and boots, while; the minor percentage (38.7%) are using respirator as an index for safety climate of working environment.
5. Less than one half of the workers have health profile for shortness of breathing with mild excretion (49.4%), chronic cough (44.6%) andAsthma (39.3%).The majority of workers have not any lung or allergic diseases due to occupational reason.
6. The higher percentage for non-symptoms workers towards the overall symptoms is 93.5%, with significantly higher percentage for mild nose symptoms (53.0%) and lower percentage for breathing symptoms (12.5%), the percentage for mild eyes, sinuses symptomsare 32.1%, 31.5 % respectivelyamong the workers having (10 -15) years of employment.There is a statistically significant difference between the length of employment (years) and the median of eyes, nose and sinuses symptom. While; there was no significant difference ofthe breathing symptom as it is the minor percent of the current symptoms.
7. There was a highly statistically significant difference between the workers within the different job duties and using the PPE specially using goggles, air respirator, mask, hat and suit,which indicate the increases awareness of the management and the participated workers from different job duties about the importance of using PPE.
8. Monitoring of ammonia emission levels was observed across ten different stations in the modern nitrogenous fertilizer company and were generally below the adjusted limits of the TLV - TWA for ammonia concentration (25 ppm) by both ACGIH and NIOSH.
9. The reduction in ammonia emission levels and minimizing the potential workers health hazards especially respiratory symptoms were demonstrated as a result of implementing of the best available techniques and cleaner production technologies established by Uhde technology which provided innovative developments for ammonia and urea production. There had been a significant improvement in the catalysts used in reforming and the steam reforming section include waste heat recovery system, shift conversion, the carbon dioxide removal unit, methanation and ammonia synthesis
10. The Uhde dual-pressure process and design of ammonia plants is based on reliable and confirmed process steps. The main features are primary reformer with cold outlet manifold, secondary reformer with peripheral vortex burner, and three-bed magnetite radiator heat exchange synthesis with one or two synthesis transformers.
11. Implementing of several control technologies to control ammonia emissions includes both add-on control equipment’s as (wet scrubbers and condensate strippers) and pollution prevention techniques as recycle and recovery techniques, reducing agent limitation, capture systems and good maintenance practices, demonstrating control efficiencies up to 99%.
12. It is heartening to note that from implementing the modern developed technologies as best available techniques and adoption of cleaner production technologies in ammonia manufacturing, promotes reduction and minimizing exposure to ammonia emission positively improves health of the workers in the modern modified nitrogenous fertilizer industries.
6.3 Recommendation
In light of the results of the study, the following recommendations were suggested:
1. A large number of nitrogen fertilizer plants now require development and modernization. This is containing terms of hardware, application, and knowledge of operation and maintenance personnel, by developing smart migration strategies to upgrade old plants to the latest technology. This ensures that the plant operating company can save existing investments in the long run, increase the overall return on capital and eliminate or reduce ammonia emissions and thus reduce the risk of occupational exposure to workers.
2. The basic standards now in ammonia plants are to enhance advanced control process such as distributed control systems (DCSs) andsafety instrumented systems (SIS). Prior to the start of the plant operation, Hazard and Operational Studies (HAZOP) and Protection Layer Analyzes (LOPAs) are required for safe workplaces and occupational health improvement for workers in the nitrogenous fertilizer industries. As well as using the latest training courses and appropriate education programs to guarantee that engineers and operators can achieve their duties safely and efficiently.
3. Further studies are required to assess the improvements made to these technologies in the nitrogenous fertilizer industries and the impact of occupational exposure risks on workers’ health. On the production aspect, the developing of industrial technologies for fully producing ”green ammonia” from sustainable and carbon neutral inputs, such as renewable electricity and biomass that need more surveys. Additionally, these studies could include a number of experimental projects, which are presently underway such as a focus next generation technologies that may in the future lead to the low-cost production of carbon-neutral nitrogen fertilizers.