Comments Jianguoxu has made

  • Using liquid hydrogen as jet fuel

    As much as I dislike the idea of using hydrogen for cars, I do think there are a lot of advantages in using liquid hydrogen as jet fuel. It is light, it is clean, and its flame has a lower temperature, reducing the potentials of forming NOx.

    Now, safety may still be a concern...On Now and later posted 2 years, 9 months ago 21 Responses

  • carbon emission killers

    Let me take a stab:

    1. A safe, low cost battery (<$300/kWh) technology for PHEV with 60 miles of pure electric range that lasts more than 4000 cycles and 10 yrs,
    2. A PV technology that reduces the cost of solar cells to below $0.08/kWh on electrocity generation, installed
    3. A low cost, highly efficient heat driven heat pump that eliminates the need for the conventional heat pump
    4). A low cost system for using geothermal heat for residential heating and cooling.

    These four should be enough to reduce the amount of carbon emission by more than 90%, IMO On Global warming 'tis merely a flesh wound posted 2 years, 9 months ago 4 Responses

  • Erratum

    "My inventions in H2 PSA are being used in plants with capacitities of greater than one billion standard cubic feet per day of H2"

    in the previous post should be:

    "My inventions in H2 PSA are being used in plants with total installed capacitity of greater than one billion standard cubic feet per day of H2 - more than 25% of the H2 production capacity of this country"On Tamminen and hydrogen posted 2 years, 10 months ago 20 Responses

  • Amateurs accting as experts

    The problem I see here is a lot of amateurs are acting like experts. The read something, and thought they understand things which they don't. Yet they have the political clot, the influence in media, and may sound like experts to thoe who have no background in the area. But they really do not have the necessary knowledge and trainings to make correct analysis and judgement. Due to their influence in national and regional governments, and in the media, they can cause and have caused a lot of waste of resources, despite at least in some cases the good intention of these people.

    I did my PhD thesis in steam reforming of methane, the main means of generating H2 today - the kinetic model for steam reforming that I developed is what is being widely used in literature today. My inventions in H2 PSA are being used in plants with capacitities of greater than one billion standard cubic feet per day of H2. I have been involved in coal gasification projects, and am very familiar with generation processes. I also have patents in fuel cell-fuel processor integration, in safe dispensing of hydrogen etc. I would have a lot to gain if stored would indeed become the dominant means of energy for transportation. However, I will tell you that it does not make sense. I have listed the reasons in the previous discussion forum on this subject. Here I will only touch one important area that I did not mention earlier: Environmental impact of a H2-powered transportation system.

    If H2 for whatever reason would become the predominant source of energy for transportation, there would be a lof of H2 leaked from the filling stations and other productio and distribution channels, the vehicles etc. This leaked H2 would likely to rise to the upper atmosphere, and react with the ozone up there. I have not seen any scientific confirmation that shows this would not destroy the ozone layer.

    Without any scientific evidence that the leaked H2 would not destroy the ozone layer, how can someone say H2 is the solution to our transportation problem??? On Tamminen and hydrogen posted 2 years, 10 months ago 20 Responses

  • Why hydrogen does not make sense

    Fuel cell has been considered a future means of power source for vehicles by some people, and the government and private sector have invested billions of dollars in this area. The problem with fuel cell vehicles (FCVs) is that there are too many issues with the fuel cell technology, among which the following is fatal in my opinion: that is, di-oxygen (O2) is too inactive to react at ambient temperature. As a consequence, we have the following two issues:
    1)    The (lower heating value of hydrogen to electricity conversion) efficiency of a proton exchange membrane (PEM) fuel cell, the essentially only type of fuel cell underdevelopment for vehicle applications, is rather low-it typically does not exceed 50% when the fuel cell works at a decent power density. When the parasitic losses, including that for running the air blower and that for thermal management system, are included, the typical net efficiency of a proton exchange membrane fuel cell running at 80 deg C is in 35-45% range at the name-plate power of a fuel cell. This is only about the half of the round-trip efficiency of a typical rechargeable battery, which runs at ambient temperature.
    2)    PEM fuel cells have to be operated at an elevated temperature, typically at around 80 deg C, in order to have the desired power density/specific power to run a vehicle. Therefore, it is necessary to have an additional energy/power source for the period during which the fuel cell is being heated up, from, for example, sub-freezing temperatures. This problem is currently solved by adding a large battery or supercapacitor for running the vehicle before the fuel cell is heated up. This significantly adds to the cost of the fuel cell.

    Currently, as far as I know, there is even no speculation on how to solve this fundamental problem, let alone a plausible proposal for its solution. Such a situation is understandable since the relative inactivity of dioxygen at ambient temperature is after all the fundamental reason why the world as we see exists: without it, our furniture, all the plants and animals, including ourselves, would have been oxidized to form carbon dioxide, water, and some ashes, or rather, we would not have existed on the first place!

    The above mentioned problems are not the only serious problems with FCV's. The issues of high cost of building a hydrogen fueling infrastructure, the lack of a satisfactory hydrogen storage means, the currently too short fuel cell life, owing to catalyst deactivation due to Pt particle migration towards the separator, due to loss of active site area resulting from catalyst particle growth, due to the peeling off of the electrodes from the membrane owing to repeated dry-wet cycles that come with the use pattern of passenger cars, due to fuel cell poisoning by sulfur-compounds and other poisons, lack of enough platinum resources to support the large number of vehicles in the world, the high cost of manufacturing fuel cell stacks etc. are all difficult problems that may or may not have technical solutions, let alone cost-effective, solutions. That compares very unfavorably with the fact that ICE-battery hybrid cars, clean diesel cars, and Miller cycle cars are already commercialized and competing in the market place-the major technical problems for them are already solved.  
    On We will wonk you posted 2 years, 10 months ago 18 Responses

  • Electrification of major highways

    I am open to the best technology avaiable for such an application. However, electrically driven trolley buses were used for a long time, and are being introduced in US cities. I saw one such a line in San Francisco last November. There were two cables about 2 feet apart from each other hanging a few feet higher than the bus. I read somewhere that they are planning such a line in Washington DC also. My understanding is that this is a DC system - I am not sure of the voltage, but understand it is significantly higher than 110 V. I used to live in Shanghai. In the 70's and 80's there were many of these trolley buses running in the streets of Shanghai. I never heard of any serious safety issues associated with the falling of these cables, or discharge between the two parallel cables. However, I do remember of seeing blue sparks coming from the cable/connector at the intersections of such lines, since one couple of the cables would have to be elevated such that the contact between the connectors of the buses and the cables of buses on such lines had to be temporarily taken off, and then put back again after the bus passed the intersection area. The high voltage of the cable temporarily electrified the air between the copper cable and the (copper too?) connector, generating blue sparks when the buses were disconnected from the cables and right before the contact was established again. On Warning: techno-engineering speak ahead posted 2 years, 11 months ago 43 Responses

  • Altairnano battery

    I read about Altairnano's battery before, and was encouraged. However, I am somewhat skeptical of their data. For example, they claim their battery has 10-15 yr life. I am sure they have not done 10+ yr test. So how do they get the number? They did not explain. An explanation is needed.

    I do not know how they did the 18,000 cycle life test. It will be good to know.

    In comparison with NiMH battery, Altairnano's battery uses nano-structured materials. It is not clear how expensive it is to make them. If their cycle life and calendar life claims are true, then one question that remains is their cost.

    It will be good to see a big company getting interested in Altairnano's battery. Right now they are working with similar sized microcap companies. Lack of interest from large companies makes me wonder if they are telling the full story.

    NiH2 battery used in space industry also has tens of thousands of cycle life, and demonstrated 16+ yr calendar life (Space Telescope Hubble). But NiH2 battery has other issues, such as the high cost of the pressure vessel and the large volume which prevented it from being considered for HEV applications by a lot of people.On Warning: techno-engineering speak ahead posted 2 years, 11 months ago 43 Responses

  • Electric cars and size of battery

    I for one do not think we need a battery for 200 miles to make EV viable. When PHEV with 60 miles of range becomes commercialized, it is likely that we will install electric cables in the major highways such that when the electric vehicles run on such highways, the vehicles will be able to get the juice for running the vehicle and at the same time charge the battery. When the vehicle leaves such highways, it will run on the battery. For most places, a battery with 60 miles of range should be enough if all the expressways are electrified. At that point, no internal combustion engine is needed, either.

    What we need is a battery that can last 3000-4000 cycles.

    When that happens, the vehicles can be very simple - we no longer need the internal combustion engine, the radiator, water pump, and the rest of the cooling system, the fuel pump, the fuel tank, and the rest of the fuel system, the catalytic converter, the muffler, and the rest of teh exhaust system, and we can greatly reduce the size of the transimission system, and the lubricating system. No longer the need for change of air filters and oil change. The cost of obtaining this large savings is electrification of the major highways, which is relatively simple and inexpensive .
    On Warning: techno-engineering speak ahead posted 2 years, 11 months ago 43 Responses

  • Fallacies of "Hydrogen economy"

    I agree with many of Gar's points on the fallacies of using hydrogen for transportation. Let me add a few more:

    1. If hydrogen were to be used to power cars, there would be a lot of hydrogen leaked from hydrogen transportation, compressing, storage and during hydrogen filling. The leaked hydrogen would likely rise to the the stratosphere. It is very likely that this leaked hydrogen would cause disastrous impact on the ozone layer.

    2. PEM fuel cell life is an issue. There are many causes of fuel cell deactivation, one of which is sulfur poisoning. The Pt catalyst of a PEM fuel cell is very susceptible to poisons. 10 ppb of sulfur can cause the FC to lose capacity. The amount of sulfur on roads is higher than 10 ppb. Some of it comes from auto fume, some from degradation of organics. Occasionally, skunks provide some sulfur content peaks in air.

    3. The Pt production capacity in the world is only a very small fraction of what is needed for manufacturing the FCV's of the world. There would be a Pt supply issue. Chances are small that enough Pt can be discovered to allow FCV's to be used in most of the cars in the world.

    4. PEMFC works at about 80 deg C. It takes time to heat a fuel cell from subfreezing temperature to 80 deg C. Before reaching 80 C, the FC cannot provided the power needed. A separate, high power energy storage device is needed. That may be a large battery or supercapacitor, which adds to the cost of the car greatly.

    5. There is no good, inexpensive hydrogen storage means today. Prospect of finding such a storage means is not good.

    6. The cost of building a hydrogen manufacturing - distribution infrastructure is very high. Before such an infrastructure is present, nobody wants to buy a hydrogen car. Before hydrogen cars are wide-spread, no company wants to spend money to build hydrogen filling infrastructure.

    The list can go on-and-on. While it might be possible that some of the problems can be solved through government intervention, others are technical problems or resource problems that may or may not have technical solutions,  or solution at all, let alone cost-effective solutions.

    However, the biggest issue with hydrogen-powered transportation is that there are better alternatives. For example, hybrid vehicles are already commercialized. A hybrid vehicle costs only a few thousand dollars more than the conventional vehicle, and the battery and motor comes with 80,000 to 100,000 mile warranty. This compares with the $1 million price tag of a FCV, and its probably less than 50,000 mile practical fuel cell life. There are no technical issues in converting hybrid vehicles into plug-in hybrids. The only issue to resolve for commercialization of plug-in hybrids is the cost of the battery, which may really come in the form of battery life - the NiMH battery used in today's hybrids can only last for about 1000 cycles, while a plug-in hybrid needs a battery that can last 3000-4000 cycles.  The efficiency of an electric vehicle is in the order of 75-95% (round trip), far exceeding that of a PEMFC's 50% or so. While it is true that there are inefficiencies in converting fossil fuels to electricity (60% for state-of-the-art gas turbine-steam turbine cycle using natural gas for an apple-to-apple comparison with H2 from steam reforming of NG), the overall efficiency of the electric vehicle route is still significantly better than the steam reformer - fuel cell route. When electricity is produced by renewable sources, such as wind energy and solar energy, this advantage is even further, greatly, increased. Besides, at present as well as in future, electric vehicles or plug-in hybrids can also be used to store electrical energy at low demand period of the day, which can greatly improve the efficiency of the power grid utilization. Wide-spread of PHEV's and EV's will allow the power companies to convert many of the lower efficiency (e.g., typically NG-powered gas turbine plants with 20+% efficiency) peak-shaving plants into the higher efficiency base-load plants (as was mentioned, the state-of-the-art combined cycle plants have an efficiency of about 60%), thereby indirectly, but significantly, increase the efficiency of the power plants.On Warning: techno-engineering speak ahead posted 2 years, 11 months ago 43 Responses