Engines with no gaseous emission

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Engines with no gaseous emission
Energy Advancement Leadership Conference GEMI, UH

• Fazle Hussain, Valery Zimin and Dhoorjaty
  Pradeep
• fhussain_at_uh.edu

Institute of Fluid Dynamics and Turbulence
University of Houston
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Motivation

• Improved performance from inherently
  high-efficiency cycles
• Carnot cycle impractically high compression
  ratios for even realistic temperature ranges
• Two cycles with Carnot efficiency
• Stirling cycle (isochoric heat regeneration/isothe
  rmal expansion and compression) also
  impractical due to very high pressures
• Ericsson cycle (isobaric heat regeneration/isother
  mal expansion and compression) modest pressure
  ratios deliver high efficiency e.g. 87.5 with
  2400 K.

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Alleviating Pollution

• Hydrocarbon combustion ? H20 CO2
• Chief problem NOx
• Solution combustion with pure Oxygen
• Advantages
• No NOx
• Temperature restricted by materials alone
• Handling of exhausts far easier
• (a) lower mass flow rate
• (b) fewer chemical components
• Cost
• Energy for air separation (not very large)

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Key features

• Applications local power plants, large
  vehicles, ships

Environment no NOx CO, CO2 sequestration
Thermodynamics Ericsson cycle, near-Carnot
efficiency, high-temp
combustion
Technology separation of N2 and O2 from
air, ceramic
expansion chamber heat
regenerator variable torque without
gearbox
Economics low construction and maintenance
costs, use of low-grade fuels
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Ericsson cycle
(1 ? 2) Isothermal compression with water spray
injection (2 ? 3) Isobaric expansion in heat
regenerator compressed gas heated by
counter-flowing exhaust (3 ? 4) Isothermal
expansion achieved by proper timing of fuel
injection during combustion in the expansion
chamber
(4 ? 1) Isobaric compression in heat regenerator
due to cooling of the exhaust flow
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Power plant schematics
Mass balance is shown for 1kg/sec flux of fuel
(CH4)
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Two emisionless-engine designs

• Vortex Engine for low-grade fuels (e.g. biomass)
• Rotary Engine for high-grade fuels (e.g. natural
  gas)

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Vortex engine for low-grade fuels

• Steady-flow combustion engine
• Centrifugal forces support pressure difference
• Density stratification suppresses turbulence,
  decreasing thermodynamic irreversibility
• No moving parts in high-temp zone ?ceramics
  possible
• High efficiency direct-contact radiative heat
  transfer between counter-flowing fluids at
  different pressures
• Intense flow driven by centrifugal convection
• Continuous removal of slag from combustion zone
• Efficient energy conversion using MHD generator

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Key components of rotary engine

• Air separator
• Isothermal liquid ring compressor
• Ceramic heat exchanger expander
• High-temp isothermal combustor
• CO2 liquefier
• Water-spray cooler

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Liquid-ring compressor
1 - casing 2 water ring 3 expanding cavity 4
low pressure 5 intake port 6 intake
manifold 7 collapsing cavity 8 high
pressuure 9 stationary collector 10 exhaust
port 11 - exhaust manifold
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New combustor/expander
1 - stationary core 2 - ceramic lining of
core 3 rotor 4 - ceramic lining of rotor 5 -
sliding vane 6 - stationary cam.
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Expander operation
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Innovative heat exchanger
High-temperature part

• Key features
• Use of high conductivity ceramics
• Designed for only compressive loading on the
  ceramic components

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Energy balance

• Power from combustion of 1kg/s CH4
• at 87.5 thermodynamic efficiency 43.75 MW
• Amount of O2 consumed 4 kg/s
• Power consumed by N2 O2 separator 4 MW
• Losses due to leakage in expander (estimated at
  0.6) 0.26MW
• Loss due to heat flux through ceramic layers of
  expander (1.1) 0.48MW
• Losses due to leakage in compressor (estimated at
  1.2) 0.53 MW
• Power consumed by CO2 liquefier (with
  recuperation) 0.15 MW
• Estimated losses in heat regenerator 1.8 MW
• Other losses (frictional, incomplete
  combustion) 0.85 MW
• Total available work 35.68 MW
• Energy density of CH4 combustion 50 MW
• Overall plant efficiency 71.4

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Experimental 10 kW set-up
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Summary
1. Use of the Ericsson cycle provides high
thermodynamic efficiency 2. Isothermal
combustion occurring in this cycle is the most
thermodynamically beneficial way to heat the
working fluid 3. Cooling by a water spray
provides effective isothermal compression 4.
Separation of O2 and N2 (from air by an
energy-efficient O2 plant) and release of N2 to
atmosphere before combustion ensures no NOx in
the engine exhaust 5. Use of CO2 as the working
fluid allows us to exhaust liquefied CO2.
This feature drives down the cost of CO2
separation and permits CO2 sequestration. 6. Use
of ceramic tiles (for the inner surface of the
combustion chamber and other high-temperature
zones of the engine) that makes the engine
feasible. 7. The high temperature of combustion
and multiple returns of combustion products to
the combustion zone prevents CO pollution.