Novel Zeolite Adsorbents for the Production of Clean Diesel

Novel Zeolite Adsorbents for the Production of Clean Diesel
Problem Description
Sulfur is the main contaminant of diesel fuel, and it is present in a concentration that ranges between 0.1% and 0.5%. Its combustion produces sulfur oxides such as SO2 and SO3, which can be discharged to the atmosphere causing great damages to the environment and human health. For instance, the exposure of the sulfur oxides to atmosphere leads to acid rain that leads to both air and water pollution. Reducing the sulfur content in hydrocarbon fuels will help improve the performance of catalytic converters. Because sulfur compounds (SO2 or H2S) have a negative effect on the performance of the reactor. Moreover, even a very low concentration of sulfur in the fuel can impact the performance of hydrogen fuel cells as sulfur compounds can poison the anode of the cell by blocking active sites for hydrogen oxidation.
Recently, many researchers have been developed for advanced technologies seeking to obtain economically viable and efficient alternatives to remove sulfur from petroleum-derived fuels. Due to the increased awareness of the environment and the damage that sulfurs compounds because once emitted, stricter regulations are being put. Such regulations ensure that factories and vehicles do not emit a large amount of sulfur compounds, which exposes adverse risks to the environment. It is now required that sulfur levels in diesel and gasoline be brought down to a maximum of 15 and 40 ppmw (parts per million on a weight basis) from the current levels of the order of 430 and 130 ppmw, respectively. These new requirements for sulfur content demand the use of new deep desulfurization processes to produce ultra-low sulfur diesel (ULSD)

Statement
This project aims to design a low-cost adsorbent for the production of clean diesel fuel. Where, Natural zeolite adsorbents will be surface-modified via ion exchange and used to remove the sulfur compounds in diesel fuel. Also, Different metal ions will be used for the production of novel adsorbents. Batch adsorbers will be used to test the adsorption of sulfurs. The kinetic and equilibrium parameters obtained will be used to scale up the process for the practical production process. As a result, the project would be important for understanding the design and process of producing clean diesel fuels after adsorption process.
Scope of Work
The project will consider the different approaches and design for diesel desulfurization, which would counter the growing environmental concerns. The presence of sulfur components in the fuels has significant adverse environmental impacts in the society. It also will evaluate the adsorption process, which helps in the desulfurization of diesel.
The production Capacity of Diesel
Our project is upon diesel desulfurization process, in such process capacity of the adsorption matters. To determine the capacity of our design for the diesel desulfurization production plant, we had scanned the market demand and supply for diesel. For such purpose, we examined the amount of diesel produced by the UAE. The UAE usually exports a large amount of the unrefined diesel and imports clean diesel, this due to some economic reasons. However, the domestic consumption is expected to grow by 2,000 to 3,000 bpd, but the Abu Dhabi National Oil Company (ADNOC) has expanded diesel production capacity by 10,000 bpd. Which made the UAE plane to produce 400,000 to cut reliance on diesel exports. Thus, we would design our plant to cope with such a demand. At the same time, the plants need to reach the standards of the clean fuels to meet European regulations and help control air pollution throughout the Arabian Gulf. Therefore, the project would determine the important European regulations and policies critical in the overall desulfurization of sulfur.
Importance of Diesel Desulfurization
The demand for transportation fuels has been increasing in most countries for past two decades. Which made using clean diesel as an essential requirement. Thus, the world environmental protection agency had fixed a limit for the sulfur content of diesel fuel. Sulfur is a naturally occurring component in diesel. The removal of organosulfur from hydrocarbon fuels is important, to reduce the emissions of sulfur compounds discharged into the atmosphere, which affect health and environment. Health effects are the main concern about high levels of sulfur dioxide being emitted. The main route of exposure is inhalation. Inhalation of SO2 can be the cause of severe irritation in the throat and nose, and in high concentrations is life threatening. Sulfur compounds can react with other compounds in the atmosphere, forming tiny sulphate particles. These sulphate particles are particularly dangerous as, when they are inhaled, they penetrate deep into the lungs and can cause respiratory diseases leading to difficulty breathing and premature death. Other health effects include skin and eye contact, where the SO2 gas irritates and burns the skin or eye. Contact with skin can cause scarring and contact with the eye may result in blindness.
The major environmental impact of SO2 in the atmosphere is that it reacts with other substances in the air and forms acid. The acid produced can be deposited through either wet deposition or dry deposition. Wet deposition occurs through precipitation, where rain, snow and hail among others, which eventually it deposits into the ground. Dry deposition occurs when acid gasses stick to the earth’s surface in the absence of precipitation. Acid rain has a variety of adverse effects including acidification of lakes, damage to trees at high elevations, corrosion of buildings and statues among others can damage soil by changing its pH level. The project will examine all potential designs and approaches useful in the production of ultra low sulfur diesel in the society to reduce the potential environmental impacts.

Novel Zeolite Adsorbents for The Production of Clean Diesel (Desulfurization)
Problem statement and Significant
Sulfur is the main contaminant of diesel fuel and it is present in a concentration that rages between 0.1% and 0.5%. Its combustion produces sulfur oxides such as SO2 and SO3 which can be discharged to the atmosphere causing great damages to the environment and human health. Reducing the sulfur content in hydrocarbon fuels will help improve the performance of catalytic converters. Because sulfur compounds (SO2 or H2S) have a negative effect on the performance of the reactor. Moreover, even a very low concentration of sulfur in the fuel can impact the performance of hydrogen fuel cells as sulfur compounds can poison the anode of the cell by blocking active sites for hydrogen oxidation.
Recently, many researches have been developed for advanced technologies seeking to obtain economically viable and efficient alternatives to remove sulfur from petroleum-derived fuels. Due to the increase awareness of the environment and the damage that sulfurs compounds cause once emitted, stricter regulations are being put. It is now required that sulfur levels in diesel and gasoline be brought down to maximum of 15 and 40 ppmw (parts per million on weight basis) from the current levels of the order of 430 and 130 ppmw, respectively. These new requirements for sulfur content demand the use of new deep desulfurization processes to produce ultra-low sulfur diesel (ULSD) [1].
1. Project Goals
This project aims to design a low cost adsorbent for the production of clean diesel fuel. Where, Natural zeolite adsorbents will be surface-modified via ion exchange and used to remove the sulfur compounds in diesel fuel. Also, Different metal ions will be used for the production of novel adsorbents. Batch adsorbers will be used to test the adsorption of sulfurs. The kinetic and equilibrium parameters obtained will be used to scale up the process for practical production process.
The production Capacity of diesel
Our project is upon diesel desulfurization process, in such process capacity of the adsorption matters. To determine the capacity of our design for diesel desulfurization production plant, we had scanned the market demand and supply for diesel. For such purpose we examined the amount of diesel produced by the UAE. The UAE usually exports the large amount of the unrefined diesel and imports clean diesel, this due to some economical reasons. However, the domestic consumption is expected to grow by 2,000 to 3,000 bpd, but the Abu Dhabi National Oil Company (ADNOC) has expanded diesel production capacity by 10,000 bpd. Which made the UAE plane to produce 400,000 to cut reliance on diesel exports. Thus, we would design our plant to cope with such a demand. At the same time, the plants need to reach the standards of the clean fuels to meet European regulations and help control air pollution throughout the Arabian Gulf. [2]
Diesel Components
Since the used method in diesel desulfurization process adsorption the process would be selective towards the components of diesel. It is therefore imperative that the composition of diesel is known in case there is an issue of any side reactions with the adsorbent. Diesel chemical composition is approximately 75% paraffin hydrocarbons and 25% aromatic hydrocarbons. Many different types of sulfur compounds are contained in diesel fuel. These sulfur compounds are presented in the following table: [3]
Name of the compound Structure Description
Dibenzothiophene, (C12H8S) (DBT) This compound is fairly stable which makes it difficult to be selectively removed. It can also have an effect on the environment, especially aquatic life where it can reside for a long time with continuing toxicity.
4-Methyldibenzothiophene (C13H10S)(MDBT)
This is very similar properties and stereochemistry as DBT. The only difference is the added methyl group on one of the benzene rings. Environmental impacts aren’t considered as serious as the release of DBT but they should be minimized as much as possible.
4,6-Dimethyldibenzothiophene (C14H12S)
Its stereochemistry is very similar to MDBT except DMDBT has an extra methyl group. This compound has the highest melting point of the organo-sulfurs considered of 153-157°C and has the appearance of a slightly off-white powder. The environmental impact of a direct emission of DMDBT are small, however should it be combusted the emissions could be very harmful, as is true with all the organo-sulfurs.

Importance of diesel desulfurization
The demand for transportation fuels has been increasing in most countries for past two decades. Which made using clean diesel as an essential requirement. Thus the world environmental protection agency had fixed a limit for sulfur content of diesel fuel. Sulfur is a naturally occurring component in diesel. The removal of organo-sulfur from hydrocarbon fuels is important, to reduce the emissions of sulfur compounds discharged into the atmosphere, which affect health and environment. Health effects are the main concern about high levels of sulfur dioxide being emitted. The main route of exposure is inhalation. Inhalation of SO2 can be the cause of severe irritation in the throat and nose, and in high concentrations is life threatening. Sulfur compounds can react with other compounds in the atmosphere, forming tiny sulphate particles. These sulphate particles are particularly dangerous as, when they are inhaled, they penetrate deep into the lungs and can cause respiratory diseases (e.g. bronchitis and emphysema), leading to difficulty breathing and premature death. Other health effects include skin and eye contact, where the SO2 gas irritates and burns the skin or eye. Contact with skin can cause scarring and contact with the eye may result in blindness.
The major environmental impact of SO2 in the atmosphere is that it reacts with other substances in the air and forms acid. The acid produced can be deposited either through wet deposition or dry deposition. Wet deposition occurs through precipitation, where rain, snow, hail etc. which eventually it deposits into the ground. Dry deposition occurs when acid gasses stick to the earth’s surface in the absence of precipitation. Acid rain has a variety of adverse effects including: acidification of lakes, damage to trees at high elevations, corrosion of buildings, statues etc. and can damage soil by changing its pH level. [4]