Integrated microalgae production and electricity cogeneration

• US 5,659,977 A
• Filed: 04/29/1996
• Issued: 08/26/1997
• Est. Priority Date: 04/29/1996
• Status: Expired due to Fees

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Cyanotech Corporation
• Inventors: Reichl, Eric H., Jensen, Glenn
• Primary Examiner(s): Sollecito, John M.
• Assistant Examiner(s): GRAVINI, STEPHEN MICHAEL
• Application Number:
  US08/641,159
• Time in Patent Office: 484 Days
• Field of Search: 34/526, 34/535, 34/547, 34/548, 34/586, 34/61, 34/62, 34/66, 34/82, 34/85, 34/86, 34/90, 110/245, 432/58, 435/292.1, 47/1.406, 47/1.407, 60/648
• US Class Current: 34/547
• CPC Class Codes: A01G 33/00 Cultivation of seaweed or algae
• CPC Class Codes: B01D 2252/103 Water
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• CPC Class Codes: B01D 2257/708 Volatile organic compounds V.O.C.'s
• CPC Class Codes: B01D 2257/80 Water
• CPC Class Codes: B01D 2258/012 Diesel engines and lean burn gasoline engines
• CPC Class Codes: B01D 53/265 by refrigeration (condensation)
• CPC Class Codes: B01D 53/62 Carbon oxides
• CPC Class Codes: B01D 53/84 Biological processes
• CPC Class Codes: B01D 53/8668 Removing organic compounds not provided for in B01D53/8603 - B01D53/8665
• CPC Class Codes: B01D 53/94 by catalytic processes
• CPC Class Codes: C12M 21/02 Photobioreactors culturing algae A01G33/00, A01H4/001, C12N1/12
• CPC Class Codes: C12M 23/18 Open ponds; Greenhouse type or underground installations
• CPC Class Codes: C12M 33/10 by centrifugation centrifuges in general B04B; Cyclones cyclones in general B04C
• CPC Class Codes: C12M 43/04 Bioreactors or fermenters combined with combustion devices or plants, e.g. for carbon dioxide removal C12M43/06 takes precedence; recovery of carbon dioxide C12F3/02
• CPC Class Codes: C12M 43/08 Bioreactors or fermenters combined with devices or plants for production of electricity
• CPC Class Codes: C12M 47/14 Drying
• CPC Class Codes: C12M 47/18 Gas cleaning, e.g. scrubbers; Separation of different gases separating dispersed particles from gases or vapours B01D45/00; separation of gases or vapours B01D53/00; gas washing apparatus for laboratory uses B01L5/04
• CPC Class Codes: C12M 47/20 Heating or cooling heating or cooling apparatus for laboratory uses B01L7/00
• CPC Class Codes: F01N 5/02 the devices using heat
• CPC Class Codes: F02G 5/02 : Profiting from waste heat of exhaust gases
• CPC Class Codes: F26B 23/001 : using waste heat
• CPC Class Codes: Y02A 40/80 : in fisheries management
• CPC Class Codes: Y02A 50/20 : Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
• CPC Class Codes: Y02C 20/40 : of CO2
• CPC Class Codes: Y02E 20/14 : Combined heat and power generation [CHP]
• CPC Class Codes: Y02P 20/59 : Biological synthesis; Biological purification
• CPC Class Codes: Y02P 60/20 : Reduction of greenhouse gas [GHG] emissions in agriculture, e.g. CO2
• CPC Class Codes: Y02P 70/10 : Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working
• CPC Class Codes: Y02T 10/12 : Improving ICE efficiencies

Abstract

An integrated plant including a microalgae production plant for growing, harvesting and drying algae and a fossil fuel-motor-generator plant producing electrical energy. A fossil fuel engine produces hot exhaust gas from which sensible heat dries the algae. The drying may be direct from the exhaust gas or may be indirect with the hot exhaust gas exchanging sensible heat with a recirculating stream of inert gas. Carbon dioxide from the exhaust gas is recovered for use as a nutrient in the microalgae production plant. Electrical energy from the generator is used to drive motors and/or produce artificial illumination and/or drive pumps, motors and controls in the microalgae production plant.

Claims

1. An integrated plant including a motor-generator plant with a microalgae production plant for growing, drying and harvesting algae, comprising:

A motor-generator fueled with fossil fuel for generating electrical energy and hot exhaust gas containing carbon dioxide;

A microalgae culture pond containing water having a high CO₂ content and impeller means for circulating said water;

Collecting means for recovering microalgae and water from said culture pond;

dewatering means for recovering moist microalgae;

thermal dryer means for drying said moist microalgae to produce dried microalgae as a product;

Means for recovering hot exhaust gas from said motor;

means for transferring sensible heat from said hot exhaust gas to dry said moist microalgae;

CO₂ recovery means for collecting CO₂ from cooled exhaust gas in an aqueous solution;

water delivery means for delivering said aqueous solution containing CO₂ to said culture pond.

2. The integrated microalgae production/motor-generator plant of claim 1 wherein means are provided to deliver a portion of said electrical energy to drive said impeller means.

3. The integrated microalgae production/motor-generator plant of claim 1 wherein an aqueous stream from a separation means is returned to said culture pond along with said aqueous solution containing CO₂ recovered from said exhaust gas.

4. An integrated microalgae production/motor-generator plant of claim 1 wherein:

Said hot exhaust gas is introduced directly into said thermal dryer means to dry a filter cake.

5. An integrated microalgae production/motor-generator plant of claim 1 wherein:

A means for recovering hot exhaust gas from said motor includes heat exchange means for recovering sensible heat from said hot exhaust gas and means for transferring sensible heat to a recirculating inert gas stream;

passing said recirculating inert gas through said dryer means to dry said moist microalgae; and

means for delivering the cooled exhaust gas to said CO₂ recovery means.

6. The integrated microalgae production/motor-generator plant of claim 5 wherein said recirculating inert gas stream passes sequentially through a spray dryer, a separation cyclone, a condenser and said heat exchanger means.