Biodiesel and its Effects on Air Quality in Carlisle
What is Biodiesel?
As an alternative fuel, biodiesel, greatly reduces harmful emissions.
“Biodiesel is defined as the mono-alkyl esters of fatty acids derived from vegetable oils or animal fats” (Building a Successful Biodiesel Business, 2006, Page 3). Simply put, biodiesel is an alternative to petrodiesel which is derived from vegetable oils or animal fats.
The process in which the vegetable oils must go through to be turned into biodiesel is call transesterification. “Transesterification is the process of reacting a triglyceride molecule with a excess of alcohol in the presence of a catalyst (KOH, NaOH, etc.) to produce glycerol and fatty esters” (Building a Successful Biodiesel Business, 2006, Page 4).
The vegetable oils are brought to a temperature of 130º Fahrenheit and then reacted with a mixture of methanol or ethanol and lye, potassium or sodium hydroxide. The lye acts as a catalyst to neutralize the free fatty acids in the oil. Once the reaction is complete biodiesel and glycerin are left. For every gallon of oil put into the reaction you receive a gallon of biodiesel and for every gallon of methoxide, methanol and lye mixture, you receive and gallon of glycerin. Due to the nature of lye, soap is created in this process as well. To make the biodiesel usable in engine the soap must be washed out with water. The water is passed through the biodiesel slowly collecting the soap, this mixture of water and soap separates from the biodiesel and is then put down the drain. Now the biodiesel is almost entirely free of soap, but the soap has been replaced with water. The water must be removed from the biodiesel by either, heating and circulating it or by placing a vacuum over the biodiesel. Once the biodiesel is “dry” it can go out to for use in cars, trucks, furnaces, farm equipment, etc.
Advantages and Disadvantages
Advantages
There are many advantages to using biodiesel as opposed to ethanol gas. The first advantage of using biodiesel is that it comes from renewable energy sources. Biodiesel comes from plants which can be replenished. Another advantage is that renewable fuels are carbon neutral. Plants can recapture the carbon dioxide that is emitted from burning renewable fuels. The carbon dioxide is seperated into carbon and oxygen and most carbon is put into the ground while the oxygen is released back into the atmosphere. With renewable fuels, plants are able to naturally balance carbon dioxide emissions (From the Fryer to the Fuel Tank p. 19-20).
Economic Stimulation
The third main advantage to using biodiesel fuel is that it could potentially strengthen the United States economy. Currently, the renewable fuels industry counts for an insignificant amount of the nation's GDP, however, it has the potential to create over one million jobs, add over $50 billion to the economy, and decrease the trade deficit by at least 30%. The Department of Energy suggests that for every $1 billion reduction in the US trade deficit 27,000 jobs are gained. If all fuel is domestically produced the annual trade deficit will be decreased by $53 billion and create 1.43 million jobs. (From the Fryer to the Fuel Tank p. 21-22). The production of biodiesel does not require intense training, so jobs would be accessible to many currently unemployed Americans.
Additional Benefits
Additional benefits to using biodiesel fuel such as its lubricating qualities that help increase the engine life. Biodiesel can also be used in most existing oil heating systems and diesel engines without modification and can be stored where petroleum diesel is currently stored which is an advantage over other alternative fuels. The cost of production for biodiesel fuel can also be significantly cheaper than ethanol because it can be produced from cooking oil or soybeans which are currently being overproduced. Biodiesel also provides roughly the same energy per gallon as petroleum diesel.
Disadvantages
While the advantages of biodiesel fuel certainly outweigh the disadvantages, it is important to acknowledge the downside of biodiesel use. The most evident disadvantage of biodiesel is that it is presently one and a half times more expensive to produce than petroleum diesel when it is made from soybeans. The costs are greatly reduced, however, when it is made from recycled cooking oils. Biodiesel can damage the rubber hoses in some old engines (particularly in cars manufactured before 1994) and can also clog filters by bringing up dirt and debris from the fuel tank. An additional disadvantage is that there are increases in nitrogen oxide emissions. The final disadvantage is that B100 fuels are generally not suitable for use in lower temperatures.
Carlisle Air Quality
Almost 60% of all NOx and more than 70% of all PM2.5 in Cumberland County comes from diesel engines (CAAQAR, 11). However, the majority of fine particulate matter and nitrogen oxides in Carlisle do not come from the use of diesel. Besides being a major trucking hub, Carlisle is also a big manufacturing town. Most of these pollutants in Carlisle come from those industries, which act as point source polluters. Point source polluters are defined as “large, stationary industrial facilities” in the Carlisle Area Air Quality Assessment Report from November 14, 2006, which was presented by Carlisle Health & Wellness Foundation. These facilities must be given a permit to pollute by an environmental agency and are either monitored by continuous emissions monitoring from there stack or by periodic monitoring (CAAQAR, 16-17). The point source polluters make up 106,258 tons of the 126,823 tons per year of nitrogen oxides emitted and 7,687 tons of the 11,171 tons per year of fine particulate matter (CAAQAR, 16-17). This equates to 83.6% of the nitrogen oxides and 68.8% of the PM2.5 that is emitted each year into Carlisle (CAAQAR, 16-17). The next highest polluter of PM2.5 and the third highest polluter of NOx are stationary areas. Stationary areas may include “commercial charbroiling restaurants, gas stations, on-site diesel generators, dry cleaners and auto body paint shops” (CAAQAR, 16-17). These areas contribute 5.8% of the NOx at 7,410 tons per year and 28.6% of the PM2.5 at 3,193 tons per year (CAAQAR, 16-17).
The final sources of PM2.5 and NOx are mobile emissions. In terms of NOx mobile sources produce 10.3% of the total tons per year in Carlisle equaling a total of 13,155 tons (CAAQAR, 16-17). As for PM2.5, mobile sources produce 2.6% of the total tons per year in Carlisle equaling 291 tons (CAAQAR, 16-17). The mobile emissions can be broken down into two categories, on-road and off-road. Off-road mobile includes “vehicles such as heavy construction equipment (e.g., bulldozers and cranes); farm equipment (e.g., tractors); and lawn and garden equipment” (CAAQAR, 16-17). On-road mobile can be then split into sub categories consisting of heavy-duty diesel (trucks and buses), other diesel and gasoline. The “other” category refers to cars and small trucks, which make up 2.5% of the total mobile source of NOx, 332 tons per year, and 2.7% of the PM2.5of the total, 8 tons per year (CAAQAR, 16-17). Gasoline on-road mobile sources produce the second most NOx pollution and the third most PM2.5 pollution. They generate 4,774 tons of NOx per year, 36.3%, and 52 tons of PM2.5 per year, 17.8% (CAAQAR, 16-17). Off-road mobile sources emit 1,067 tons of NOx per year, 8.1% of the total mobile sources, and 36.1% or 105 tons of PM2.5 per year (CAAQAR, 16-17). Finally, the heavy-duty diesel on-road mobile sources emit the majority of both NOx and PM2.5 at 53.1% of NOx and 43.3% of PM2.5 (CAAQAR, 16-17). This equals 6,982 tons of NOx per year and 126 tons of PM2.5 per year (CAAQAR, 16-17). The majority of pollutants are produced by heavy-duty on-road mobile sources. The three other mobile sources produce less NOx than the heavy-duty but more PM2.5 as a whole, although each source individually produces less than the trucks and buses.
Besides emitting nitrogen oxides and fine particulate matter, diesel fuel combustion produces a number of other pollutants. These pollutants include such things as carbon monoxide, carbon dioxide, sulfur, unburned hydrocarbons and aromatic hydrocarbons as well as a noxious smell. Aromatic hydrocarbons are, “toxic compounds such as benzene, toluene and xylene” (Pahl, 2005). A few other toxic compounds that diesel exhaust contains are “toxic substances like arsenic, benzene, biphenyl, chlorine, cobalt compounds, cyanide compounds, dioxins, formaldehyde, inorganic lead, mercury compounds, polycyclic aromatic hydrocarbons (PAHs) and toluene” (Carlisle Air Quality Assessment Report, 2006). These pollutants are released in smaller quantities than nitrogen oxides or fine particulate matter and thus tend to cause fewer health problems due to the lower levels emitted from diesel exhaust.
Emissions
As discussed before, the burning of diesel fuel emits many pollutants that are both harmful to people and the environment. One of the critical advantages to biodiesel is that those emissions are substantially decreased. The net CO2 emissions reduction is a total of about 100%, this is because biodiesel being burnt emits about 78% less CO2 and the 22% is absorbed by the feedstock (Tickell, 38). The reductions in both carbon monoxide and hydrocarbons by 10-50%, compared to petroleum based diesel fuel (Tickell, 38). There are reductions in the polycyclic aromatic hydrocarbons, in phenanthren by 97%, in benzofloroanthen by 56%, in benzapyren by 71% (Tickell, 38). As for the compounds that cause the greatest health issue the reduces are considerable. SO2 emissions are reduced by 100%, this will cut the fine particulate matter generated by the conversion of SO2 down to nothing (Tickell, 38). The amount of soot or particulate matter from the exhaust of the diesel vehicles is cut by 40-60% (Tickell, 38). The one area that biodiesel does not reduce emissions significantly, or at all in some cases, is NOx, the emission are either increased or decreased by 5-10%, depending on the engine (Tickell, 38). All of these numbers are dependent of the age of the motor, newer the engine the better the reduction in pollutants. Another option for diesel vehicle owner to reduce emissions is to tune the engine run on biodiesel.
Based on the numbers generated by the Carlisle Area Air Quality Assessment Report from 2006, we will examine the reductions in emissions of NOx and PM2.5. All of the calculations are based on the assumption that all the engines are new and tuned to burn biodiesel.
The 22,400 trucks passing through Carlisle per day were to operate on B20, 20% biodiesel and 80% petrodiesel, the reductions of PM2.5 would reduce by an average of 12% and the NOx emissions would be reduced by 1.5%. This would reduce the amount of PM2.5 to 110.88 tons per year and the NOx would be reduced to 6877.27 tons per year; meaning that there would be 18.84 tons of NOx emitted each day and .304 tons of PM2.5 emitted each day. These numbers are not a great improvement but they would be a step in the right direction.
If we increase the amount of biodiesel blended with petrodiesel to 80% the reductions increase to 48% for PM2.5 and 6% for NOx. The tons per year of PM2.5 would drop to 65.52 or .18 tons per day and the NOx emissions would drops to 6563.08 tons per year or 17.98 tons per day.
If the trucks passing through Carlisle each day where to run on B100, 100% biodiesel, the NOx would be reduced by an amount of 7.5% or 6458.35 tons per year or 17.69 tons per day. PM2.5 would reduce by 60% to 50.4 tons per year or .138 tons per day. The reductions in NOx, considering best case scenario, are not as significant as those for PM2.5 or other pollutants, but they are a reduction and to sacrifice those emissions for others would be better than no reductions.
References
-Tickell, Joshua. From the Fryer to the Fuel Tank. New Orleans, LA: Joshua Tickell Media Productions, 2003. Print.
-Pahl, Greg. Biodiesel: Growing a New Energy Economy. White River Junction, VT:Chelsea Green Publishing Company, 2005. Print.
-Estill, Lyle. Biodiesel Power. Canada: New Society Publishers, 2005. Print.
-"Carlisle Area Air Quality Assessment Report." Carlisle, PA: Carlisle Health & Wellness Foundation, 2006. Print.
-Gerpen, Jon H.V., Pruszko, Ruby., Clements, Davis., Shanks, Brent. "Building a Successful Biodiesel Business." Biodiesel Basics, 2006. Print.
-Image: Transesterfication process of biodiesel: 529 × 706 pixels: http://ecosyseng.wetpaint.com/page/The+one+stage+old+and+the+two+stage+new+process
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-Image: Potential of biodiesel to reduce harmful emissions: 394 × 360 pixels: http://arizonabiodiesel.com/BioDieselBenefits_MCAQD.htm
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