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					  ZERO EMISSIONS
 MEMBRANE PISTON
ENGINE SYSTEM FOR A
        BUS

JISHIN
S8 ME
NO 36
• Preventing global warming will require drastic
  engineering measures to curb emissions of carbon
  dioxide.
• Stabilizing the world’s climate will require high income
  countries to reduce their emissions by 60-90%
   There exists a source of pollution that Is more
   dangerous w.r.t green house effect
                 It is the combustion products of
                  about half a billion of cars and
                    other vehicles, using piston
                              engines.
                            zempes                           2
     Vehicles and Emissions
• The fleet of half billion of piston engine –driven
  vehicles is a big and dangerous polluter.
• Piston engines discharge combustion products directly
  into the atmosphere as exhaust

                                    water vapour(benign)
          (piston
    engine)combustion
         products
                                    carbon dioxide(green
                                         house gas)

                           zempes                          3
• carbon dioxide, can not be decomposed
  at the end of the pipe due to energy conservation Law

• To cope with the problem of CO2 emissions two main
  approaches have been underway:
           a) increasing efficiency and
           b) Shift to other, non carbon,
              fuels like hydrogen and electricity.


                           zempes                         4
        WHY ZERO EMISSION
          TECHNOLOGY?
• The use of hydrogen as fuel or electricity
  leads to very large energy storage onboard, which exceeds
  the vehicle size.

• To have enough energy density the hydrogen
  should be compressed in a fuel tank up to 700 bar!!!

• Results in change of existing infrastructure, filling stations,
  fuel supply systems e.t.c.

• All this leads to high cost
                                zempes                              5
• Electrically driven vehicles
       the charging electricity, produced largely by
      fossil- fuel-fired power plants
      they are not zero emissions technology
      can not prevent global warming.
• A new scheme is proposed for a piston engine vehicle
  propulsion system
• It would not discharge any carbon-containing
  combustion products with the exhaust.
  a zero-emissions engine burning ordinary hydrocarbon fuel.
                            zempes                             6
 • First type - turbine one
 • described fuel combustion in a mixture of oxygen and
   steam.




                                                       3
P=240 bar, t=1000 c




                      A mixture                              the CO2
                                  2



                                      expanded in a
                       of steam       turbine to 0.5       recirculated
                                      bar and               in part to
                      and CO2
                                      condensed               the
                                                           combustor.


                                           zempes                         7
• The CO2 that was not recirculated was
     separated from the liquid water, compressed,cooled
     stored onboard in the empty space vaccated by fuel.

• The main problem with such schemes is in the provision
  of oxygen.

• To solve this problem
        the use of a capsule with solid oxygen (oxygen
      ice) at 50 K was proposed in 1994
                            zempes                          8
ZEMPES outlook for a bus on
   compressed methane




               zempes         9
  SCHEMATIC OF THE PROPOSED
           SYSTEM
• It includes a piston engine with a fuel injection
  system
• either injection into the induction manifold or directly
  into the cylinders.
• at point 1
         Air enters the air compressor
• from 2 to 3
         It is compressed, then heated in a heat exchanger
         It then enters the Ion Transport Membrane Reactor
         (ITMR)

                           zempes                       10
• Here about 60% of the oxygen from the air is
  transferred through the membrane wall to the permeate
  side
• the diffusing oxygen is swept by the flow of combustion
  products, CO2 + H2O.
• points 4-5
  Water, separated from the gaseous CO2, is injected into
  the flow of air to increase the turbine power.



                           zempes                           11
• After expansion,air (depleted of oxygen) and
  steam are discharged into the atmosphere
• these exhaust constituents are absolutely harmless.
• exhaust gases from the piston engine is cooled in
      ITMR, in the heat exchanger, and in radiator-cooler
  that has a fan
• At near-ambient temperature the water is liquid, whereas
  CO2 is gaseous-they are easily separated.
• The dry mixture of CO2 and O2 enters the engine, where
  atomized fuel is injected.
                           zempes                        12
ZEMPES schematic




            zempes   13
at point 9                          point 10                        The CO2 is then
the exhaust constituents are        The minor part, 15%, is         stored in liquid form
CO2, H2O & some                     deflected out of the            in the
contaminants                        cycle , then compressed         fuel/CO2 tank with a
                                    to about 70 bar                 sliding baffle ,to be
• The major part of the exhaust
                                                                    discharged at a
  gas is directed to the permeate   • It is cooled in a radiator-
  side of the ITMR                                                  fuel filling station.
                                      cooler to liquefy the CO2

• It diffused with permeated
  oxygen




                                          zempes                                        14
ADVANTAGES OF THE SCHEME

• use of a turbo compressor provide hot compressed air
  to the ITMR

• permit the acceptance of heat transfer from the exhaust
  gases to produce additional power.

• This arrangement is referred as Otto-Brayton power
  cycle.



                           zempes                           15
ITM REACTOR
• construction

     like an ordinary shell-and-tube heat exchanger
     tubes made of dense ceramic membrane material.


• It sweep away the penetrated oxygen.




                         zempes                        16
• The selectivity of such membranes is 100% and the
  permeability of O2 is about 1 g /m2sec

• At the recommended temperatures (800-900 C) and
  pressures (air 5 bar), the oxygen flux density reaches
                j = 1 g/m2sec.

• This reliable averaged figure is used to evaluate the
  size of the ITMR.

                            zempes                         17
• The typical power output of a bus engine is
   about 240 kW.
• Assuming the thermal efficiency is 30 %, the required
  heat rate is 800 kW.
• If one tube has a diameter of 0.02 m and a length of 0.5
  m, the membrane surface area, A, is 0.0314 m2.
• The calorific value of the fuel per stoichiometric unit
  mass of O2, H, is 12.5 MJ/kg.
• The eventual heat rate associated with one tube is
           AjH = 0.0314 0.001 12.5 106
                            zempes                           18
• W = 0.39 kW.

• For a heat rate of 800 kW,
               800/0.39 = 2052 tubes are needed

• The size of the turbine and the compressor depends upon the
  air flow rate.

• The volume of a piston engine of 240 kW is about 1 m3.

• The total volume of the ZEMPE system (without the CO2
  tank) is about 2 m3

                             zempes                             19
The parameters at the node points are
           given in table




                      zempes            20
   CALCULATION OF MASS AND
       ENERGY BALANCE
• Figures for the calculated power of some of the
  components of the system and the overall
  efficiency are given.




                        zempes                      21
• The figures ,
      a volume of 2 m3 and a system efficiency
       of 28 % with a 240 kW engine for a bus
       a volume of 0.7 m3 with a 78 kW engine for a car
are similar to those for ordinary piston engines.

• This shows the feasibility of a zero emission bus or car
  that would run on ordinary fuel.


                            zempes                           22
             CONCLUSION
• The ZEMPES approach could readily be
   combined with hybrid vehicle technology that is already
  in commercial use.

• This allow the use of smaller engines, with reductions in
      the size of the ancillary components
       in the volume of CO2 liquid to be stored on board.




                            zempes                        23
              REFERENCES

• [1] IEA Zero Emissions Technology Status Report,
  2002, www.iea.org/impagr/zets/status/0202tsr.pdf
• [2] Beta R & D Ltd., http://www.betard.co.uk/
• [3] E. Yantovski, The Thermodynamics of Fuel-fired
  Power Plants without Exhaust Gases.
• [4] F. Viteri et al, Hydrocarbon combustion power
  generation system with CO2 sequestration,US Pat.
  6,170,264 B1, Jan. 9, 2001.
• [5] F. Viteri, Clean air engines for transportation and
  other power applications. US Pat.6,247,316, June 19,
  2001.
                            zempes                          24
THANK
 YOU

				
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posted:11/10/2012
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