Skip navigation

Category Archives: diesel engine

Bioethanol has successfully substituted Gasoline as a fuel for cars both in the form of blends with Gasoline or individually as an Anhydrous Ethanol. This  successful demonstration by Brazil opens up new generation of cars called flex-fuel cars that allow usage of various blends of Ethanol and Gasoline.Bioethanol can also be used to generate Hydrogen on site by steam reformation so that even Fuel cell cars such as Honda FCX can be felled by Bioethanol.This makes Bioethanol unique as an alternative fuel for transportation. It also facilitates on site electricity generation using Fuel cell, replacing diesel engines.

Substitution of Gasoline by  Bioethanol has several advantages over other alternative fuels. The biggest advantage with Bioethanol is, it is renewable and it allows reduction of greenhouse gases from the atmosphere and will be eligible for Carbon credit. It can be produced by both developing  as well as developed countries using  locally available agriculture produces such as cane sugar, corn, tapioca, sorghum etc. Hydrogen generated from Bioethanol is also free from Sulfur compounds normally associated with natural gas, making it an ideal fuel for Fuel cell application in cars, as well as for power generation using SOFC (solid oxide Fuel cell) or PAFC (Phosphoric acid Fuel cell).The resulting high purity Hydrogen 99.99% can be used as fuel for all type of transportation including Fuel cell Buses, scooters and even boats.

The stoichiometric reaction of steam reformation in presence of catalyst can be represented by the following chemical reaction:

C2H5OH + 3 H2O———- 6H2 + 2 CO2

The Ethanol and water mixture is preheated and the vaporized mixture is fed into a catalytic reactor. The resulting Hydrogen is contaminated with carbon monoxide. This gas mixture is separated using membrane such as Palladium to get Hydrogen with less than 50ppm CO as contaminant. Such purity is acceptable by Fuel cell such as SOFC as well as PAFC.In future a small micro-reactor for on-board reformation may be possible making Fuel cell cars with onboard liquid fuel storage.

Commercial reformers consumes about 0.88 lits of Biothanol of 96% purity to generate 1 Nm3 of Hydrogen with 60% conversion. This translates to $ 5.90 per Kg of Hydrogen. Fuel cell cars offer a mileage of 240 from 1 kg Hydrogen costing only $5.90. For on site power generation 1 kg Hydrogen generates as much as 15Kw electricity and 20Kw heat .Onsite Hydrogen generation with steam reformation also facilitates using SOFC and PAFC for high temperature power generation applications. They are ideal for CHP (combined heat and power) applications for 24×7 operations like hospitals, hotels and super markets. These fuel cells are silent in operation without any emissions except water vapor.

Governments should encourage Bioethanol production and distribution for both transportation and power generation. There is a fear that Ethanol could be diverted for potable purposes illegally depriving Governments of potential reveneues.But this can be solved by denaturing Bioethanol and making it unsuitable for potable purposes. Denaturants such Pyridine has no effect on steam reformation and number of denaturants are available. Such policies will allow the transition from fossil fuels to Hydrogen or Bioethanol.This is a simple and straight forward step any Government can take irrespective of the size or type of nation. But it requires political will, determination and leadership. Developing countries need not wait for big greenhouse emitters such as US, China and India to make a decision on their Carbon emissions but start introducing Bioethanol as fuel locally.

Photovoltaic  solar industry has started expanding in recent years in US and Europe and the rest of the world also started following. Still solar energy is considered expensive in many parts of the world for various reasons. In most of these countries, energy is predominantly managed by Governments with age-old technologies and transmission systems. Coal is still the major fuel used for power generation and distribution and their infrastructures are old and inefficient. Transmission losses, power pilfering, subsidized power tariffs and even free power for farmers, are some of the issues that compounds the problems. Energy and water are considered more of social issues rather than business issues. For example in India, frequent power failures are common  and sometimes people do not have power even up to 8 to 12 hours  a day, especially  in country sides. Standby diesel generators are integral part of an industry or business. The heavily subsidized power supply by Government from coal-fired power plants is  underrated. The average power tariff in India is still less than $0.07/kwhr.But the reality is they will be using diesel generated power for equal several hours in a day  and the cost of diesel power varies from  $0.24 up to $0.36/kwhrs, almost in par with solar power. The average power cost will amount to $0.18 to $0.20 /kwhrs.

Any slight increase  in oil price will have a dramatic effect in energy cost in India and their balance of payment situation.Governments are in a precarious situation and they have to make a balancing act between subsidizing the energy cost and winning the elections. They often subsidize the power resulting in heavy revenue losses for Government run electricity boards. Most of the electricity boards in India are in red. People are used to low power tariffs for several decades and any increase in the tariff will make the Government unpopular. Greenhouse effect and global warming are secondary issues. With an average economic growth rate at 7% year after year, their energy requirements have gone up substantially. They may need several hundred thousands of MW power in the next 5 to 10 years. They have opened up energy sector to private only in recent years.

Renewable energy industry is relatively new and there are very few large commercial-scale solar and wind power plants in India. Majority of residents and businesses cannot afford high cost of PV solar installation. Even if they install, there is no ‘power- in tariff’ mechanism by Government where consumers can export surplus energy at a higher tariff to the grid. With current power failures lasting 8-12 hours/day, such mechanisms will have no value. The situation is the same in many Asian countries.

The solar panel costs are high due to lack of local production of silicon wafers, batteries and inverters and most of them are still imported. State electricity boards do not have funds to buy power at higher tariffs. Import duties and taxes on imported components are still high making renewable industries uncompetitive against cheap coal-fired,  subsidized power cost of $0.07/kwhrs .India requires massive investment on renewable energy industries. But most of the power projects which are under planning stage or under implementation are based on either coal or oil or LNG.There is no sign that India will soon become a major player in renewable energy.

In PV solar projects, the cost of storage batteries are higher than the solar panel during the life cycle of 25 years. If the life of a battery is 8 years then you will need 3 batteries during the life cycle. For example, if you use 100 watts solar panel with a life span of 20 years, the initial cost of solar panel may be $300 which will generate an average power of 140 watt.hrs /day. If you plan to store 5 days energy using a battery, you will enquire 5x 140= 700 watt.hrs battery, costing about $175.If you have to replace batteries 3 times during the life span of 20 years then the cost of battery is 3×175= $525.You have to add operation and maintenance cost, in addition to it. Therefore, your investment on batteries is 1.75 times more than solar panels. This cost will substantially add up to your energy cost.

In most of the Asian countries where they cannot export surplus power to the grid, they have to rely only on batteries. This high cost of stored energy is not remunerative because they cannot export this surplus to the grid at a higher tariff. This situation is not likely to change at least in the short-term.

There is a general opinion that Hydrogen is now very expensive compared to Gasoline and Diesel. It depends on how you generate Hydrogen. We have used Gasoline and Diesel for several decades and real cost of crude oil is much lower than what we are paying for Gasoline and diesel at the service stations. Crude oil is formed naturally and all the cost involved is for pumping, transportation and refining. The cost of energy spent on transportation and refining is also comparatively low. It is the geopolitical situation in the world, supply demand gap, Government taxes and levies, inventory levels, financial market and distributors play a key role in fixing the price of these fuels.

Hydrogen can be generated from tap water without involving fossil fuels at all. But Governments are spending on research and development of Hydrogen generation using fossil fuels such as natural gas and coal. It is understandable that these sources are suitable for bulk production of Hydrogen on an industrial scale. We will also be able to use existing fossil fuel infrastructure to the most extent. But the flip side of this approach is Hydrogen generated by this route is still not pure enough to meet Fuel cell requirements. This Hydrogen may be suitable for Hydrogen combustion engines. Why they are not suitable? For example, Hydrogen is generated from natural gas by steam reforming,Syngas is generated as an intermediary product which is a mixture of Hydrogen and Carbon monoxide; but also other impurities present in natural gas such Sulfur,Phosphorus and Mercaptans etc.Natural gas has to be purified to remove all these impurities before it can be subject to steam reformation. In spite of an elaborate purification methods adopted, Fuel cell suppliers are reluctant to guarantee the life of their Fuelcell.The Fuel cell uses expensive Platinum as a catalyst which can be readily poisoned by the presence of impurities in Hydrogen, produced from natural gas. This is one of the main reasons why Hydrogen becomes expensive by this route. Industries can pay high cost for this Hydrogen, but ordinary citizens cannot afford to pay.

Hydrogen can be generated directly from tap water by simply electrolyzing it using a Direct current such as solar and wind. If we use grid power, it requires about 68kwhrs of electricity, costing about $3.40 per Kg of Hydrogen. Assuming Hydrogen will cost about $5 per kg after compression and storage, it is still worth the cost. This Hydrogen will give a mileage of 73.4 miles/kg using Fuel cell car. This is equal to 3.67 Gallons of gasoline costing about $13.76, at the rate of $3.75 per gallon. It is very clear that hydrogen is cheaper than gasoline or diesel. At the current price,Gasoline  costs 275% more than Hydrogen gas.

By converting existing coal and oil based power plants into IGCC, Integrated Gasification and Combined Cycle plants, Government can cut the current emission levels of greenhouse gases, and at the same time supply electricity at the prevailing rates. We do not have to import oil or gas. Government should fund conversion of coal and oil-fired power plants into IGCC plants and create Hydrogen infrastructure, by producing more Hydrogen Fuel cell cars and Hydrogen service stations. By adopting this policy, US Government can bring down the prices of crude oil in the international market which will help cut the prices of all other petrochemical products like fertilizers, plastics, drugs and cosmetics. The crux of the issue is to divert petroleum products from fuel use to other uses. At the same time Governments can reduce their greenhouse emissions to the level demanded by scientists. By reducing the cost of solar panels to less than $.100 per watt, Renewable Hydrogen will become a commercial reality and that will be the end of fossil fuels.

Wind is a potential source of renewable energy, especially for islands with an average wind velocity of 5mts/sec and above. Many islands in pacific ocean  have some common problems like sea erosion, shortage of power and drinking water. These small islands with little population are fully depending on diesel fuel. In fact their life depends on diesel fuel and any increase in price significantly affects their daily life. Their main source of income is only by fishing and they live day to today.

I had a personal experience of visiting a small island off Port Moresby in Papua New Guinea. They call it Dougo Island or ‘Fisherman’s island’ with population of less than 700 people. It is about 4.5km wide and 2km long. It is a coral atoll pushed out of the sea. One can take stroll on the beach and it is one of the most beautiful experiences one can have. It gives a feeling that you are far away from the rest of the world. There is a small abandoned World War II Airfield. The people in the island do not have any electricity or drinking water and most of them are fishing on small boats. Their boats are fuelled by diesel. They will go to nearby city of Port Moresby and sell their fish and with that money they will buy drinking water and diesel in cans and return to the island. This is their daily life.

Such an island is an ideal location to set up a wind turbine and a small sea water desalination plant, that can easily solve their problem of water and power. The trade wind from the Coral Sea in the island of Papua New Guinea blows almost 7-8 months in a year and their wind velocity averages 7 mts/sec. Two wind turbines of each 250 kW capacity and a small seawater desalination SWRO plant of capacity 15,000lts/day will be sufficient to solve their problems. The desalination plant will consume about 4.5Kwhrs/m3 of water generated. About 2000 kwhrs/day of power can be supplied to the village, each family consuming about 2.85 khrs/day for 6 hours/day and also for the desalination plant. The system will generate  a surplus power.

Renewable wind energy is the best option for such islands to generate on-site power and also to desalinate seawater for supply of drinking water. With increasing global warming and sea level rising, these small island face seawater intrusion and inundation. Many islands are slowly disappearing into the vast sea. Moreover, these islands are the most vulnerable to the fluctuating diesels prices and they are walking on a tight rope.Industrialised countries with an average power consumption of several kilowatt-hours per day are crying foul about rising energy cost while people in such small islands barely manage their food and shelter after paying for the diesel.

Recently the Government of Maldives conducted their cabinet ministers meeting under the sea, to showcase their plight due to sea level rise caused by global warming, to the rest of the world. Small islands can cry loud but their voice  is muffled by roaring sea, while rest of the world carries on their business as usual.

Do you use a generator that runs on diesel or gas to power your business due to frequent power outage from the grid? Are you running an air-conditioner with the grid power? Then you must look for waste heat recovery system to improve your energy efficiency and save your fuel cost. You can also use roof top solar hot water to supplement waste heat recovery. The savings may be real and you may be able to recover your investment in a short period and also contribute for the reduction of greenhouse emissions.

The diesel or gas engine converts only most 30% of fuel input in the form of thermal energy into mechanical energy to run your generator, and the balance heat is wasted in the form of greenhouse gas. You can recover this heat and increase the efficiency of the system. This means for the same amount of diesel used, you will get much higher output in the form of heating or cooling or in the form of additional electricity.

The exhaust temperature from a gas engine is about 420C.You can also recover extra heat from jacket cooling. Let us assume that you have a natural gas-fired engine to generate 100kw electricity for the premises. The efficiency of such spark ignited reciprocating gas engines are typically about 30%, which means a natural gas input of 1.145 mm Btu/hr. Let us assume the cost of piped natural gas at $10 per mm Btu; the fuel cost will be about $ 11.45/hr.

The exhaust heat from the engine will be about 801,500 Btu/hr; with waste heat recovery efficiency at 75%, the heat recovery will be 601,125 Btu/hr.You can air-condition premises with an area of 35-40 square meters using this recovered waste heat. If you use grid power   at the rate of $0.10/kwhr, to run the air conditioning system for the above area, you will be spending about 30,000kwhrs of electricity per month, costing about $ 3000 per month. By installing an absorption chiller to air-condition your premises using engine exhaust heat, you will be saving about $36,000 per year towards air-conditioning. The air-conditioning system may cost about $130,000, and with the above savings you will be able to get a return on your investment in less than 3 years.

If you have a roof-top solar water heater then you can supplement it with your engine exhaust heat water so that the capacity of the air-conditioning can be increased. It is one of the best methods by which an energy efficiency of a fossil felled engine can be increased. If the capacity of the engine is much higher, there are other methods by which the efficiency can be increased.

For example, the hot water from the exhaust system can be used to generate some extra power using an ORC, organic Rankin cycle. It is similar to a steam turbine. An organic liquid with low boiling point will be evaporated into vapor by a low heat source such as hot water from engine exhaust, which runs a turbine, generating some extra power and condensing back into the liquid, and then the cycle continues. You will be able to generate an extra electricity of about 15-18% making the total electrical efficiency of the system  to 45-50%, which is similar to a Fuel cell system, but at a much lower cost.

Heat recovery system with an absorption chilling and using low heat source to generate extra power using ORC, are best methods to improve energy efficiency of an existing system with little investment. The purpose of such integration is to increase the energy efficiency of the existing system, so that you will be getting more output of energy from the same input of fuel.




%d bloggers like this: