Biogas fuel conditioning system

An inventive biogas fuel conditioning apparatus for removal of moisture and other unwanted constituents from a wet biogas stream in order to supply dry conditioned biogas fuel to a fuel consumer, said apparatus comprising:

• a blower, said receiving, pressurizing, and warming a wet biogas stream in order to provide a substantially constant-pressure biogas stream flow to the fuel consumer;
• a first heat exchanger receiving and cooling the wet pressurized warm biogas stream from said blower;
• a second heat exchanger receiving the cooled wet biogas stream from said first heat exchanger and further chilling the wet biogas stream to a predetermined temperature to condense substantially all moisture in the biogas stream;
• a first filter receiving the chilled biogas stream from said second heat exchanger and removing the condensed moisture to provide a dry biogas stream;
• said first heat exchanger then receiving and warming the dry biogas stream from said first filter by heat exchange with the incoming wet pressurized warm biogas stream;
• and
• a third heat exchanger further warming the dry biogas stream from said first heat exchanger;
• wherein said second heat exchanger and said third heat exchanger are in refrigerant flow relation with one another.

A method of conditioning biogas for use by a biogas consumer, said method including sequential steps of:

• flowing the biogas at a first temperature of about 80° F. to about 100° F. to a blower;
• utilizing said blower to both increase the pressure of the biogas, while also increasing its temperature to a second temperature in the range of about 140° F. to 160° F.;
• utilizing a first heat exchanger to lower the temperature of the biogas to a third temperature of about 80° F. to 100° F.;
• flowing the biogas through a chilling heat exchanger cooled by refrigerant so as to lower the temperature of the biogas to a fourth temperature of about 34° F. to 40° F., and utilizing the decreased temperature of the biogas to condense unwanted water from the biogas;
• flowing the biogas through a coalescing filter to substantially remove condensed water;
• flowing the dry biogas again through the first heat exchanger in heat exchange relation with biogas entering this heat exchanger at said second temperature and exiting at said third temperature, to recover heat thus warming the biogas to a fifth temperature of a range between about 75° F. to about 80° F.;
• utilizing heat transfer between the wet and dry biogas streams in said first heat exchanger to raise the temperature of the dry biogas toward a temperature approximately 35° F. above its dew point, so that substantially dry and superheated biogas is provided;
• and
• utilizing a siloxane filter to remove carbon dioxide (Co2) and hydrogen sulfide (H2S) from the biogas.

A continuous-flow method of conditioning a biogas stream, said method including sequential steps of:

• flowing a biogas stream at a first temperature to a blower;
• utilizing said blower to increase the pressure of the biogas stream and also increasing the temperature of the biogas stream to a second temperature;
• utilizing a first heat exchanger to lower the temperature of the biogas stream to a third temperature;
• flowing the biogas stream through a chilling second heat exchanger lowering the temperature to a fourth temperature and condensing unwanted water;
• flowing the biogas stream through a coalescing filter to substantially remove condensed water;
• flowing the biogas stream again through the first heat exchanger in heat exchange relation with the biogas stream entering this heat exchanger at the second temperature and exiting at the third temperature, so as to recover heat in said heat exchanger and warming the biogas stream to a fifth temperature, so that said fifth temperature is above its dew point of the biogas stream, and thus providing a substantially dry biogas stream;
• and
• filtering carbon dioxide (Co2) and hydrogen sulfide (H2S) from the biogas stream;
• further including the step of utilizing a direct refrigerant-evaporating type of heat exchanger as said second heat exchanger.

A continuous-flow method of conditioning a biogas stream, said method including sequential steps of:

• flowing a biogas stream at a first temperature to a blower;
• utilizing said blower to increase the pressure of the biogas stream and also increasing the temperature of the bio gas stream to a second temperature;
• utilizing a first heat exchanger to lower the temperature of the biogas stream to a third temperature;
• flowing the biogas stream through a chilling second heat exchanger lowering the temperature to a fourth temperature and condensing unwanted water;
• flowing the biogas stream through a coalescing filter to substantially remove condensed water;
• flowing the biogas stream again through the first heat exchanger in heat exchange relation with the biogas stream entering this heat exchanger at the second temperature and exiting at the third temperature, so as to recover heat in said heat exchanger and warming the biogas stream to a fifth temperature, so that said fifth temperature is above its dew point of the biogas stream, and thus providing a substantially dry biogas stream;
• and
• filtering carbon dioxide (Co2) and hydrogen sulfide (H2S) from the biogas stream;
• further including the step of arranging said second and a third heat exchangers in refrigerant flow relation with one another.