METHANOL PRODUCTION

In the view of long-term energy requirements, methanol has some advantages over other alternative fuels like natural gas and LPG in terms of being renewable source.

• Methanol can be produced from natural gas. But, methanol production from natural gas causes considerable amount of energy loss. Due to this reason, this process can not be counted as a viable solution for methanol production.

  Methanol production from coal are inherent some problems like as more carbon dioxide emission than that of refining and using gasoline and energy loss. In spite of these drawbacks the amount of coal reserves is many times greater than that of gasoline and natural gas. It has a promise for being future's energy source for transportation.

Figure 1. Steps of Methanol production

• Biomass and urban refuse provides long-term supply for production of methanol. Th ratio of produced energy from methanol to input of nonrenewable energy which is necessary for the conversion of biomass to methanol can be as high as 2.3 .

Source: [MOGER]

ETHANOL PRODUCTION

There are basically two methods available for ethanol production.

• Fermantative method is based on the fermantation of methanol from corn, sugar, cellulosic and alternative crops. Due to the lack of available land area for corn grain and inefficiency of converting process, production of ethanol from alternative fuels and cellulosic feedstocks seems more promising method.

• Catalytic hydrolysis of ethylene (petroleum product) is the primary synthetic method.

 

Figure 3. Production of ethanol

ALCOHOL FUELS IN IC ENGINES

The relatively simple structure of alcohol fuels compared with conventional fuels and being a single component result in several differences in the fuel properties. We can list the main fuel characteristics for alcohol fuels as follows:

• Alcohol fuels have higher octane rating. This make them suitable for spark ignition. However, due to their low cetane number, it is difficult to use these fuels in diesel engines.
• Because the alcohols contain oxygen in their chemical form, they require less air to complete combustion. (A/F ratio is low with alcohol fuels)
• The range with alcohol fuels is less than with conventional fuels, because of their low heating values. However, energy efficiency is increased with alcohol fuels due to their high compression ratio and wider flammability limit which allows leaner combustion.
• Although their high heat of vaporization cause cold-starting problem, it enhances volumetric efficiency by making fuel-air mixture dense.
• Methanol and Ethanol have lower Reid Vapor Pressure than gasoline. This creates a cold-start problem at low ambient temperatures. The requirement of using volatile starting aids or auxiliary devices occur in this kind of situations.
• Despite the wide range of flammability limit of alcohols provide them possible for leaner combustion, it causes potential safety problem. For instance, air saturated with methanol vapor at 20 C includes approximately 13 % of the alcohol which is the range of flammability limit. Due to this, it is required to take necessary steps to prevent the contact of vapor from sparks or flames. This safety problem is not available with gasoline and diesel fuel at normal ambient temperatures. Since, at saturation the gasoline vapors are too rich to ignite and diesel fuel vapors is too lean to ignite.
• Although gasoline can not get benefit from the potential advantageous of lean combustion due to its narrow flammability limit and rapid decrease in flame speed with leaner mixtures, alcohol fuels have wider flammability range and higher flame speed under lean conditions.
• Low flame luminosity of methanol causes safety concern. The formation of submicroscopic soot particles during the combustion process provide the luminosity of a carbon containing fuel. These particles which are heated by the flame emit light at visible wavelengths in a process called gray-body radiation. When methanol burns, it has a cooler flame and a few soot particles occur. The flame of methanol radiates at infrared wavelengths due to the absence of gray-body radiation.

  A visible luminous flame during the combustion process is a desirable fuel characteristic in point of safety wiev in order to detect of the flame in the event of an accidental fire. Non-luminous flame can cause danger to people close to the fire. Some additives can improve the luminosity of methanol.

• The best combination of components which improve the luminosity are those with unsaturation, cyclization, and aromoticity.
• Toluene and cyclopentane improve the luminosity in the initial part of the combustion. Indan enhances the luminosity at the final part of the combustion.

No	Test Number	Manufacturer	Vehicle Type	Engine Type	Vehicle Model	Mileage	Gross Weight (lb)	Testing Weight (lb)	Engine Power (hp)	Engine Speed (rpm)	Fuel Type
M1	TBCC-2137-M100	TMC	Bus	DDC 6V-92TA DDEC II	1994	9484	39500	32650	277	2100	M100
M2	TBCC-2138-M100	TMC	Bus	DDC 6V-92TA DDEC II	1994	66742	39500	32650	277	2100	M100
M3	RTA-3012-M100	RTS	Bus	DDC 6V-92	1988		36900	31457	277	2100	M100
M4	TBCC-2138-M100	TMC	Bus	DDC 6V-92TA DDEC II	1994	15415	39500	32595	277	2100	M100
M5	TBCC-2137-M100	TMC	Bus	DDC 6V-92TA DDEC II	1994	17854	39500	32595	277	2100	M100
M6	RTA-3012-METH	RTS	Bus	DDC 6V-92	1988	52547	36900	32322	277	2100	M100
M7	SCRTD-1276-METH	TMC	Bus	DDC 6V-92TA	1992	1104	39500	34893	277	2100	M100
M8	TBCC-2136-M100	TMC	Bus	DDC 6V-92TA DDEC II	1994	22582	39500	32595	277	2100	M100
M9	TBCC-2136-M100	TMC	Bus	DDC 6V-92TA DDEC II	1994	42100	39500	32595	277	2100	M100
M10	TBCC-2137-M100	TMC	Bus	DDC 6V-92TA DDEC II	1994	17854	39500	32595	277	2100	M100
D1	HM-1995-D2	GMC	Bus	DDC 6V-92TA	1983	24031	36900	32160	277	2100	#2 D
D2	ADEQ-4433-D2	TMC	Bus	DDC 6V-92TA	1988	15858	36900	31339	277	2100	#2 D
D3	PaT-2077-D2	ORN	Bus	DDC 6V-92TA	1991	1064	39221	34046	277	2100	#2 D
D4	PTTW-421-D2	BIA	Bus	DDC 6V-92TA	1990	8668	38000	33437	277	2100	#2 D
D5	RTA-9001-D2	TMC/RTS	Bus	DDC 6V-92TA	1990	128901	36900	31499	277	2100	#2 D
D6	BSDA-8455-D2	FLX	Bus	DDC 6V-92TA DDEC II	1988		39500	33757	277	2100	#2 D
D7	BSDA-8466-D2	FLX	Bus	DDC 6V-92TA	1988	178798	39500	33828	277	2100	#2 D
D8	PaT-3510-D2	NPLN	Bus	DDC 6V-92TA	1983	132234	37680	33669	277	2100	#2 D
D9	MDTA-9068-D2	FLX	Bus	DDC 6V-92TA	1990	206506	39500	33137	277	2100	#2 D
D10	MTC-2207-D2	GLG	Bus	DDC 6V-92TA DDEC II	1993	55948	39600	33234	277	2100	#2 D

EMISSIONS WITH METHANOL

There are Otto cycle engines which are designed for M100, M85 and flexible fuels (any mixture of methanol and gasoline). Diesel engines are available which run on methanol with an ignition improver.

Vehicle emissions rates and compositions vary widely with the percentage of methanol in flexible vehicles. Evaporative and refueling emissions rates g/mi from M-100 is approximately 20 % of those from gasoline engines. Total hydrocarbon emissions from M100 vehicles are estimated to be about 30 percent of those from gasoline engines. The distribution of hydrocarbon emissions is: 16 % nonmethane hydrocarbon, 81 % methanol, and 3 % formaldhyde compared to 99 % non-methane hydrocarbon and 1 % formaldhyde from gasoline engines[]. Methanol engines which run at near stoichometric air/fuel ratio provide reduction in NOx emissions, but provide little improvment in the reduction of CO emissions compared to gasoline engines with closed loop and three way catalyst. For lean-burn application, CO emissions can be reduced. But reduction in NOX emissions is not significant compared to gasoline engines. Emissions rate of toxics like benzene and 1,3 butadiene decrease with methanol relative to gasoline engines.

There is no significant difference between the M100 vehicles and #2 D vehicles in terms of CO emissions, Figure 4.

Figure 4. Comparison of CO Emissions from10 M100 and 10 #2 D Vehicles.

The emissions of NOX are much lower with M100 than those with #2D vehicles, Figure 6. The hydrocarbon emissions from M100 vehicles are similar to those from #2 D vehicles, Figure 7. It should be noted that the data for hydrocarbon emissions of M100 vehicles include a fraction of the unburned alcohol and aldehydes measured.

Figure 6. Comparison of HC Emissions from 10 M100 and 10 #2 D Vehicles.

Particulate matter emissions with M100 vehicles are negligible relative to the emissions from #2 D vehicles, Figure 7.

Figure 7. Comparison of PM Emission from 10 M100 and 10 #2 D vehicles.

Figure 8. Comparison of CO2 Emisions from 10 M 100 and 10 #2 D Vehicles.

Figure 9. Comparison of Fuel Consumption from 10 M100 and 10 #2 D Vehicles.

Table 2. M100 Vehicle emissions data

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No	Test Number	Runs of Test	CO(Avg.)	NOx(Avg.)	HC(Avg.)	PM(Avg)	CO2(Avg.)	Fuel Con.(MPG)	Btu/mile
M1	TBCC-2137-M100	4	12.5	7.5	2.28	0.15	3470	1.18	48464
M2	TBCC-2138-M100	5	10.4	7.4	1.1	0.16	3516	1.16	49003
M3	RTA-3012-M100	4	8.7	5.2	0.67	0.14	2875	1.42	40069
M4	TBCC-2138-M100	5	3.9	7	0.28	0.03	3207	1.28	44535
M5	TBCC-2137-M100	5	6.6	6.1	0.9	0.07	3094	1.32	43064
M6	RTA-3012-METH	5	7.4	12.2	0.17	0.09	2669	1.53	37165
M7	SCRTD-1276-METH	4	1.6	9.7	1.07	0.14	2737	1.5	38026
M8	TBCC-2136-M100	7	9.6	6.4	2.65	0.16	3134	1.31	43794
M9	TBCC-2136-M100	4	4.8	5.9	0.46	0.05	3137	1.31	43601
M10	TBCC-2137-M100	5	6.6	6.1	0.9	0.07	3094	1.32	43064
D1	HM-1995-D2	3	9.5	41.2	2.97	1.86	2974	3.41	38299
D2	ADEQ-4433-D2	5	19.2	46.6	1.49	4.15	3011	3.34	38911
D3	PaT-2077-D2	3	13.1	30.9	2.53	1.32	3869	2.61	49796
D4	PTTW-421-D2	7	10.4	20.4	1.82	3.47	3048	3.32	39218
D5	RTA-9001-D2	6	20.9	27.2	1.85	1.81	3129	3.21	40469
D6	BSDA-8455-D2	4	25.4	41.4	2.14	1.09	2977	3.37	38632
D7	BSDA-8446-D2	4	22.3	38.3	3.2	3.1	3226	3.11	41791
D8	PaT-3510-D2	5	10.9	44.1	3.46	1.42	3427	2.95	44142
D9	MDTA-9068-D2	4	12.6	27.5	1.74	1.85	3189	3.17	41070
D10	MTC-2207-D2	4	9.5	25.8	2.77	1.65	3761	2.69	48346

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CO2 emissions from M100 vehicles are similar to those from #2 D vehicles, Figure 9 and Figure 10 show that fuel consumption with M100 is better than that with #2 D vehicles. Then we conclude that thermal efficiency with M100 engine is better than that with #2 D vehicles.

Figure 10. Comparison of Btu/mile from 10 M100 and 10 #2 D Vehicles.

Figure 11. Comparison of Avg.Emissions from 10 M100 and 10 #2 D vehicles.

EMISSIONS WITH E95 FUEL

The vapor pressure of ethanol is less than methanol (2.5 psi versus 4.6 psi at 100 F) provides less reduction in evaporative emissions. It should be noted that like methanol, ethanol also has lower photochemical reaction rate in forming of ozone than most gasoline hydrocarbons. Although the toxic emissions like benzene and 1,3 butadiene are reduced with ethanol, acetaldhyde emissions are increased. The reactivity of acetaldhyde is less than that of formaldhyde. However, it is more reactive than unburned ethanol. The CO and NOX emissions with ethanol depend on engine and combustion strategy. Stoichometric application provides a decrease in NOX compared to gasoline engines which run on stoichometric side with three-way catalyst.

In diesel engine application, data show that CO emissions with E95 are worse than that with #2 D, Figure 12. The decrease in NOX emission with E95 is obtained relative to #2 D, Figure 13.

Figure 12. Comparison of CO Emissions from 10 E95 and 10 #2 D Vehicles.

Figure 13. Comparison of NOX Emissions from 10 E95 and 10 #2 D Vehicles.

Figure 14. Comparison of HC Emissions from 10 E95 and 10 #2 D Vehicles.

Figure 15. Comparison of PM Emissions from 10 E95 and 10 #2 D Vehicles.

Figure 14 shows the comparison of the HC emissions from 10 E95 and 10 #2D vehicles. E95 vehicles emit more hydrocarbon emissions. However, hydrocarbon emissions which is called organic mater for E95 vehicles include a fraction of unburned alcohol and aldhydes emitted.

No	Test Number	Manufacturer	Vehicle Type	Engine Type	Vehicle Model	Mileage	Gross Weight (lb)	Testing Weight (lb)	Engine Power (hp)	Engine Speed (rpm)	Fuel Type
E1	GPT2-1516E-ETHNL	TMC	Bus	DDC 6V-92TA DDEC II	1992		36900	30481	277	2100	E95
E2	GPT-1504E-ETHNL	TMC	Bus	DDC 6V-92TA DDEC II	1992	24598	36900	32254	277	2100	E95
E3	GPT-1516E-E95	TMC	Bus	DDC 6V-92TA DDEC II	1992	84896	36900	31239	277	2100	E95
E4	GPT-1516E-E95-FWT	TMC	Bus	DDC 6V-92TA DDEC II	1992	84911	36900	35717	277	2100	E95
E5	GPT-1507E-E95-EWT	TMC	Bus	DDC 6V-92TA DDEC II	1992	63557	36900	26673	277	2100	E95
E6	GPT-1507E-E95	TMC	Bus	DDC 6V-92TA DDEC II	1992	63572	36900	31226	277	2100	E95
E7	MTC-8001-E95	GLG	Bus	DDC 6V-92TA DDEC II	1993	29694	39600	35734	277	2100	E95
E8	MTC-8003-E95	GLG	Bus	DDC 6V-92TA DDEC II	1993	28722	39600	35877	277	2100	E95
E9	MTC-8002-E95	GLG	Bus	DDC 6V-92TA DDEC II	1993	31807	39600	35877	277	2100	E95
E10	GPT-1504E-E95-R	TMC	Bus	DDC 6V-92TA DDEC II	1992	94999	36900	31882	277	2100	E95
D1	HM-1995-D2	GMC	Bus	DDC 6V-92TA	1983	24031	36900	32160	277	2100	#2 D
D2	ADEQ-4433-D2	TMC	Bus	DDC 6V-92TA	1988	15858	36900	31339	277	2100	#2 D
D3	PaT-2077-D2	ORN	Bus	DDC 6V-92TA	1991	1064	39221	34046	277	2100	#2 D
D4	PTTW-421-D2	BIA	Bus	DDC 6V-92TA	1990	8668	38000	33437	277	2100	#2 D
D5	RTA-9001-D2	TMC/RTS	Bus	DDC 6V-92TA	1990	128901	36900	31499	277	2100	#2 D
D6	BSDA-8455-D2	FLX	Bus	DDC 6V-92TA DDEC II	1988		39500	33757	277	2100	#2 D
D7	BSDA-8466-D2	FLX	Bus	DDC 6V-92TA	1988	178798	39500	33828	277	2100	#2 D
D8	PaT-3510-D2	NPLN	Bus	DDC 6V-92TA	1983	132234	37680	33669	277	2100	#2 D
D9	MDTA-9068-D2	FLX	Bus	DDC 6V-92TA	1990	206506	39500	33137	277	2100	#2 D
D10	MTC-2207-D2	GLG	Bus	DDC 6V-92TA DDEC II	1993	55948	39600	33234	277	2100	#2 D

Figure 16. Comparison of fuel consump. from 10 E95 and 10 #2 D vehicles.

Figure 17. Comparison of CO2 Emisions from 10 E95 and 10 #2 D Vehicles.

Figure 18. Comparison of Btu/mile from 10 E95 and 10 #2 D vehicles.

Figure 19. Comparison of Avg. Emissions from 10 E95 and 10 #2 D Vehicles.

Figure 20. Comparison of Acetaldhyde Emissions from 10 M100 and 10 E95 Vehicles.

Formaldhyde is carcinogen. It is highly reactive aldhyde. Due to this, it is potent irritant of eyes and mucose membranes in humans. Formaldhyde emissionss increse with methanol approximately 75 % compared to diesel fuel. Formaldhyde is high with methanol combustion. it is less important with ethanol, Figure 20.

Figure 21. Comparison of formaldhyde Emission from 10 M100 and 10 E95 Vehicles

Acetaldehyde results from the combustion of ethanol much as formaldhyde is a primary combustion product of methanol, Figure 20. Compared to diesel, the acetaldehyde emission with ethanol are approximately 600 times larger. When acetaldhyde is photooxidized in the presence of NOX , the formation of peroxyacetylnitrate occurs. This compound is eye irritant and it also stores NO2 temporarily. This is important for second day effects when PAN is transported downwind. It reveals NO2 which contributes ozone formation in the presence of the transported volatile organic compounds.

No	Test Number	Runs of Test	CO(Avg.)	NOx(Avg.)	HC(Avg.)	PM(Avg)	CO2(Avg.)	Fuel Con.(MPG)	Btu/mile
E1	GPT2-1516E-ETHNL	3	16.3	24.5	4.87	0.07	2898	2.00	38057
E2	GPT-1504E-ETHNL	3	17.4	23.9	10.03	0.36	3069	1.88	40498
E3	GPT-1516E-E95	5	33.7	22	6.85	0.22	3713	1.56	49054
E4	GPT-1516E-E95-FWT	3	37.4	22.2	6.77	0.25	3899	1.47	51539
E5	GPT-1507E-E95-EWT	3	41.8	13.2	8.11	0.73	3733	1.53	49522
E6	GPT-1507E-E95	4	39.8	15	7.93	0.70	3998	1.44	52907
E7	MTC-8001-E95	4	31.2	21.6	11.63	0.40	3544	1.62	47041
E8	MTC-8003-E95	4	18.7	33.5	11.54	0.46	3681	1.57	48555
E9	MTC-8002-E95	5	19.8	19,6	12.29	0.31	3712	1.55	49002
E10	GPT-1504E-E95-R	6	27.9	11.2	5.79	0.31	2371	2.41	31494
D1	HM-1995-D2	3	9.5	41.2	2.97	1.86	2974	3.41	38299
D2	ADEQ-4433-D2	5	19.2	46.6	1.49	4.15	3011	3.34	38911
D3	PaT-2077-D2	3	13.1	30.9	2.53	1.32	3869	2.61	49796
D4	PTTW-421-D2	7	10.4	20.4	1.82	3.47	3048	3.32	39218
D5	RTA-9001-D2	6	20.9	27.2	1.85	1.81	3129	3.21	40469
D6	BSDA-8455-D2	4	25.4	41.4	2.14	1.09	2977	3.37	38632
D7	BSDA-8446-D2	4	22.3	38.3	3.2	3.1	3226	3.11	41791
D8	PaT-3510-D2	5	10.9	44.1	3.46	1.42	3427	2.95	44142
D9	MDTA-9068-D2	4	12.6	27.5	1.74	1.85	3189	3.17	41070
D10	MTC-2207-D2	4	9.5	25.8	2.77	1.65	3761	2.69	48346

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