Apparatus and method for analyzing particulate matter in gas and apparatus and method for carbon differentiating

• US 6,516,654 B2
• Filed: 12/05/2000
• Issued: 02/11/2003
• Est. Priority Date: 12/10/1999
• Status: Active Grant

• Current Assignee: Horiba Limited
• Original Assignee: Horiba Limited
• Inventors: Okayama, Junji, Fukushima, Hirokazu, Asano, Ichiro, Ikeda, Masahiko, Adachi, Masayuki, Uchihara, Hiroshi, Bando, Atsushi
• Primary Examiner(s): Williams, Hezron
• Assistant Examiner(s): CYGAN, MICHAEL T
• Application Number:
  US09/730,361
• Publication Number:
  US 20010029775A1
• Time in Patent Office: 798 Days
• Field of Search: 73/280.1, 73/280.2, 73/280.4, 73/310.7, 436/155, 436/157, 436/160
• US Class Current: 73/28.04
• CPC Class Codes: G01N 15/0618 of the filter type G01N15/0643 takes precedence
• CPC Class Codes: G01N 15/0637 Moving support
• CPC Class Codes: G01N 30/12 by evaporation
• CPC Class Codes: G01N 33/004 CO or CO2
• CPC Class Codes: G01N 33/0042 SO2 or SO3
• CPC Class Codes: Y02A 50/20 Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters

Abstract

The present invention provides a method for analyzing particulate matter in a gas for analyzing simply and with high precision the particulate matter in an engine emission and an apparatus therefor by which dry soot, SOF and sulfate in PM contained in an engine emission can be fractionated individually even in a trifle amount. The present invention further provides a carbon differentiating and analyzing apparatus capable of differentiating and analyzing with precision the organic carbon and the elemental carbon contained in a sample and capable of performing a predetermined analysis with precision in a short time by reducing the period of time required for the analysis. The present invention is constituted such that a heating furnace is provided with a filter which has caught PM contained in engine emission. The filter is heated at a predetermined temperature while passing an inert gas into the heating furnace to evaporate the SOF and sulfate contained in PM. The evaporated SOF is oxidized into CO₂ and the evaporated sulfate is reduced into SO₂. The CO₂ and SO₂ are analyzed with a gas analyzer unit, and thereafter, the filter is heated while passing oxygen into the heating furnace to oxidize the PM remaining on the filter to have it generate CO₂. The CO₂ is analyzed with the. gas analyzer unit. The present invention is constituted such that a thermal decomposition tube includes, successively from its upstream side a carrier gas inlet, a low temperature heating portion for evaporating organic carbon in the sample, and a high temperature heating portion for thermally decomposing elemental carbon in the sample, whereby the organic carbon is separated in the low temperature heating portion and the elemental carbon is separated in the high temperature heating portion.

Claims

1. A method for analyzing particulate matter in a gas, comprising:

providing a heating furnace with a filter which has captured particulate matter contained in an engine emission;

feeding an inert gas into the heating furnace;

heating the filter at a predetermined temperature while passing an inert gas into the heating furnace to evaporate the hydrocarbon and sulfate contained in the particulate matter;

actuating a controllable valve attaching a gas feeder to the heating furnace thereby restricting the flow of inert gas and permitting the flow of oxygen to the heating furnace;

oxidizing the evaporated hydrocarbon into CO₂ and reducing the evaporated sulfate into SO₂;

analyzing the CO₂ and SO₂ with a gas analyzer unit;

heating the filter while flowing oxygen into the heating furnace to oxidize the particulate matter remaining on the filter to have it generate CO₂; and

analyzing CO₂ with the gas analyzer unit.

2. The method of claim 1, wherein heating the filter while flowing an inert gas into the heating furnace, further comprising:

low temperature heating to an extent that the hydrocarbon of low boiling temperature is evaporated; and

high temperature heating to an extent that the hydrocarbon of high boiling temperature is evaporated.

3. The method of claim 1, wherein sulfate is passed through heated quartz fibers in reducing the evaporated sulfate into SO₂.

4. The method of claim 2, wherein sulfate is passed through heated quartz fibers in reducing the evaporated sulfate into SO₂.

5. An apparatus for analyzing particulate matter in a gas, comprising:

a gas feeder having a controllable valve attached thereto, the gas feeder and controllable valve capable of selectively feeding an inert gas or oxygen to a heating furnace;

a heating furnace for heating at a predetermined temperature a filter in an inert gas atmosphere, the filter capable of capturing the particulate matter contained in the engine emission;

an oxidation reduction processor for oxidizing or reducing the gas generated by heating; and

a gas analyzer unit for determining the concentrations of CO₂ and SO₂ under supply of a gas from the oxidation reduction processor.

6. A method for analyzing particulate matter in a gas, comprising:

providing a heating furnace with a filter which has captured particulate matter contained in an engine emission,

feeding an inert gas to the heating furnace containing the filter;

heating the filter at a predetermined temperature in an inert gas atmosphere to evaporate the hydrocarbon contained in the particulate matter;

controllably actuating a three-way electromagnetic valve attaching a gas feeder to the heating furnace thereby restricting the flow of inert gas and permitting the flow of oxygen to the heating furnace;

oxidizing the evaporated hydrocarbon into CO₂;

analyzing the CO₂ with a gas analyzer unit;

heating the filter while flowing oxygen into the heating furnace to oxidize the particulate matter remaining on the filter to have it generate CO₂; and

analyzing CO₂ with the gas analyzer unit.

7. An apparatus for analyzing particulate matter in a gas, comprising:

a gas feeder for selectively feeding an inert gas or oxygen to a heating furnace, said gas feeder comprising an inert gas feeding passage, an oxygen feeding passage, and a connecting flow passage;

said gas feeder having a three-way electromagnetic valve controllably connecting said inert gas feeding passage, said oxygen feeding passage, and said connecting flow passage;

a heating furnace for heating at a predetermined temperature a filter which has captured the particulate matter contained in the engine emission, said heating furnace heating said filter in an inert gas atmosphere;

an oxidation processor for oxidizing the gas generated by heating; and

a gas analyzer unit for determining the concentrations of CO₂ under supply of a gas from the oxidation processor.