US 5,961,701 A · Moisture separator for digester gases and landfill gases and raw natural gases

Abstract

Two versions of centrifugal type separators capable of removing moisture from digester gases, landfill gases and raw natural gases, each separator including an upright housing having a cylindrical upper region (of a circular cross-section) and a conical lower region which tapers downwardly. A tangential inlet is located in an upper region of the housing. A gas outlet is located centrally in a top end of the housing. An outlet to remove separated liquid is provided at the bottom of the housing. There is a trap system that preferably includes a liquid holding tank for providing a positive water seal in order to prevent explosive gases from escaping through the liquid outlet. One version of separator is suitable for a high pressure gas stream, i.e., 3.0 psig or higher, while the second version is suitable for lower pressure gas streams, i.e., from 6 inches to 30 inches of water. In the second version, the water seal is formed in the conical lower region of the housing and its water level is maintained by the location of an upper end of a drain outlet line. A vent line is open to atmosphere to maintain atmospheric pressure in the drain line.

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Drawings

Claims21

Dependent claims

A separator for centrifugal separation of moisture from a moisture laden gas stream comprising:

an upright separator housing having an interior with a substantial round horizontal cross-section and a conical lower region which tapers downwardly from an upper region of the housing;
a tangential gas inlet for said gas stream located in said upper region of the housing;
a gas outlet located centrally in a top end of said housing, said gas outlet including a vertically extending pipe section connected to said housing;
a liquid outlet for removing separated liquid from said lower region;
a trap system including a liquid holding tank for providing a positive water seal in order to prevent gases from said gas stream from escaping through said liquid outlet, wherein said holding tank is connected to said liquid outlet so that liquid at a bottom end of said housing can flow through said liquid outlet and into said holding tank during operation of said separator, said trap system including a liquid level gauge mounted on said holding tank and having a first liquid level sensor for sensing when the level of liquid in said holding tank has reached a predetermined maximum height, a second liquid level sensor for sensing when the level of liquid in said holding tank has fallen to a minimum height, and a third liquid level sensor for detecting when the level of liquid in said holding tank has risen to a level above the predetermined maximum height, and wherein a solenoid control valve is opened or closed by said first and second liquid level sensors in order to control the level of liquid in said holding tank, said control valve permitting liquid to flow out of said holding tank to a drain when the level of liquid in said holding tank reaches said maximum height, and
a warning device operable to generate a warning and turned on by means of said third liquid level sensor when this sensor detects a liquid level above said predetermined maximum height.

3 more elements

A separator for centrifugal separation of moisture from a moisture laden gas stream comprising:

an upright separator housing having an interior with a substantial round horizontal cross-section and a conical lower region which tapers downwardly from an upper region of the housing;
a tangential gas inlet for said gas stream located in said upper region of the housing;
a gas outlet located centrally in a top end of said housing, said gas outlet including a vertically extending pipe section connected to said housing;
a liquid outlet for removing separated liquid from said lower region;
a trap system including a liquid holding tank for providing a positive water seal in order to prevent gases from said gas stream from escaping through said liquid outlet, wherein said holding tank is connected to said liquid outlet so that liquid at a bottom end of said housing can flow through said liquid outlet and into holding tank during operation of said separator, said trap system including a liquid level gauge mounted on said holding tank and having a first liquid level sensor for sensing when the level of liquid in said holding tank has reached a predetermined maximum height and a second liquid level sensor for sensing when the level of liquid in said holding tank has fallen to a minimum height;
a drain line connected to a bottom portion of said holding tank, said drain line being adapted to empty into a drain;
a solenoid controlled valve mounted in said drain line, said valve being opened and closed by said first and second liquid level sensors in order to control the level of liquid in said holding tank, said control valve permitting liquid to flow out of said holding tank to said drain when the level of liquid in said holding tank reaches said maximum height;
and
a by-pass line is connected to said drain line at at least one end of the by-pass line, said one end of the by-pass line being connected between said holding tank and said control valve so as to permit liquid to flow around said control valve and directly to said drain when required.

6 more elements

Dependencies are inferred from the claim text.

Description7,029 words

Summary1,429 words

#This invention relates to centrifugal type separators for removing moisture from a moisture laden gas stream consisting of such gases as digester gases, landfill gases and raw natural gases.

#Digester gas is generated by digester sludge tanks of various types and sizes. This gas is a bi-product of the anaerobic digestion process of raw sludge from waste water treatment plants. Digester gas contains approximately 70% methane (CH.sub.4), 27% carbon dioxide (CO.sub.2) and about 3% of other gases. The gas carries with it not only moisture but various impurities such as dirt. Because of its high methane content, it is classified as a hydrocarbon fuel having a calorific value in the range of 16 to 22 kJ/cu. metre. The calorific value is dependent to some extent on the moisture content. The economic viability of the anaerobic digestion process is dependent upon the quantity and calorific capacity of the gas mixture produced by the process. By using a process that reduces the moisture content, the calorific value of the gas can be increased. Digester gas can be used as a fuel for firing boilers utilized for plant heating systems, to heat digesters, and to drive engine-driven generators used to produce electrical power.

#An important factor that must be taken into account in the treatment and use of digester gas is that the gas can be explosive when it is in contact with air in a certain proportion (ie. in the range from 5:1 to 20:1).

Brief description of the drawings8 figures

#FIG. 1 is a schematic elevational view of a centrifugal cyclone-type separator designed and constructed in accordance with the invention;

#FIG. 2 is a top view of the separator of FIG. 1 showing the tangential inlet;

#FIG. 3 is a cross-sectional detail view taken along the line III--III of FIG. 1;

Detailed description5,455 words

#FIGS. 1 to 3 illustrate a preferred form of centrifugal type separator 10 for removing moisture from a moisture laden gas stream which could comprise digester gas, landfill gas or raw natural gas. This preferred separator can be constructed to automatically operate at gas pressures exceeding 3.0 p.s.i.g. (21.0 kPa). As explained further hereinafter, different models of centrifugal-type separators can be constructed that incorporate one or more features of this invention. The selection of a specific model of separator for a particular application will depend upon the gas system piping and equipment layout, operating conditions, economic considerations and other factors known in the industry.

#The preferred separator 10 has an upright separator or cyclone housing or body 12 having a cylindrical upper region 16 with an interior having a substantially circular horizontal cross-section. The illustrated body 12 has a conical lower region 14 which tapers downwardly from the cylindrical upper region 16. The upper region 16 can taper upwardly towards the roof if desired. The roof 24 has a conical frustum shape and in one preferred embodiment the slope of this roof is about 25 degrees to a horizontal plane. There is a tangential inlet 18 for the incoming gas stream located in the upper region 16 of the housing. It will be understood that a gas duct or pipe 20 normally forms the tangential inlet. In the illustrated separator, the tangential inlet 18 is located in the upper half of the upper region 16. A gas outlet 22 is located centrally in the conical roof 24 of the housing. The gas outlet includes a vertically extending pipe section 26 connected to the top of the conical roof. The pipe section 26 can terminate with a flange 27 for connection to the gas system piping. In use of this separator, the gas exiting through the outlet 22 will have increased calorific value as a result of the removal of moisture in the separator. There is also a liquid outlet 28 for removing separated liquid, normally water, from the lower region 14. The outlet 28 as shown comprises a vertical outlet pipe welded to the lower region 14 and connected to a holding tank 30 by a flanged connection.

#In one preferred embodiment of the separator 10, the conical lower region tapers inwardly at an angle Y that is 60 degrees measured from a horizontal plane.

Facts

Application

08/881,440Filed 24 Jun 1997

Priority

CA 220082524 Mar 1997

Granted

5 Oct 1999

Term ended

24 Jun 2017

Estimated · how

20 years from earliest known nonprovisional domestic filing. Maintenance-fee lapses, terminal disclaimers and statutory extensions have not been checked. The continuity chain may be incomplete; this is not an enforceability determination. Patent term adjustment is unavailable; no adjustment was added.

Classification8 codes

B04C 5/13
Construction of the overflow ducting, e.g. diffusing or spiral exits: formed as a vortex finder and extending into the vortex chamber ; Discharge…
B01D 45/12
Separating dispersed particles from gases or vapours by gravity, inertia, or centrifugal forces: by centrifugal forces
B04C 5/103
Vortex chamber constructions: bodies or members, e.g. bulkheads, guides, in the vortex chamber
B04C 5/14
Apparatus in which the axial direction of the vortex is reversed: construction of the underflow ducting; Apex constructions; Discharge…

Description7,029 words

Summary1,429 words

#This invention relates to centrifugal type separators for removing moisture from a moisture laden gas stream consisting of such gases as digester gases, landfill gases and raw natural gases.

Brief description of the drawings8 figures

#FIG. 1 is a schematic elevational view of a centrifugal cyclone-type separator designed and constructed in accordance with the invention;

#FIG. 2 is a top view of the separator of FIG. 1 showing the tangential inlet;

#FIG. 3 is a cross-sectional detail view taken along the line III--III of FIG. 1;

Detailed description5,455 words

#In one preferred embodiment of the separator 10, the conical lower region tapers inwardly at an angle Y that is 60 degrees measured from a horizontal plane.

Moisture separator for digester gases and landfill gases and raw natural gases

Life of this patent

Moisture separator for digester gases and landfill gases and raw natural gases

Life of this patent

Life of this patent

Abstract

Drawings

Drawings

Claims21

Description7,029 words

Drawings

Classification8 codes

Life of this patent

Description7,029 words