Biomass energy conversion apparatus and method

Abstract

Method and apparatus are disclosed to utilize the energy in biomass (waste agricultural products). The inventive method and apparatus utilized heat and mass flow to efficiently generate a variety of products from biomass. In various embodiment, the invention may generate a liquid fuel (such as methanol or dimethyl ether), pure liquid CO2 (intended for CO2 sequestration), a soil enhancement product (intended to return to the agricultural site), process heat, and/or electricity. In one embodiment, the process requires no external energy inputs, and preserves a large percentage (ie. >50%) of the energy contained in the biomass. In another embodiment, the inventive method and apparatus can selectively be operated to produce electricity and or liquid fuels.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of U.S. Provisional Application No. 60 / 952,506, filed Jul. 27, 2007, the entire contents of which are hereby incorporated by reference herein and made part of this specification.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention generally relates to the utilization of energy from biomass, and more particularly to a method and system that is capable of converting crop residues into one or more of a liquid fuel, electrical power or process heat.[0004]2. Discussion of the Background[0005]The prospect of converting biomass in the form of agricultural products and / or waste into fuels or energy is appealing, and is seen as a possible route to energy independence. Many such materials are considered to be waste or are disposed of in a manner that poses environmental problems. One such practice is the burning of agricultural waste, such as crop residues, in the field. Since the...

AI Technical Summary

Benefits of technology

[0008]In certain embodiments, the disadvantages of prior art are overcome by a method or apparatus which may include one or more of the following features: 1) gasifying the feedstock sequentially at increasing temperatures; 2) forming process oxygen from ambient air; 3) reacting the feedstock with oxygen; 4) providing heat for feedstock gasification from a fuel synthesis process; 5) reacting the gasified feedstock with water to produce a favorable hydrogen-to-carbon monoxide ratio, and then removing the carbon dioxide and excess water to produce a mixture useful for a conversion to fuels; 6) combining the oxidizing gas with water and / or recirculating evolved gasses to achieve the proper stoichiometry for hydrogen rich synthesis gas; 7) producing an oxygen rich gas using surplus thermal energy from partial oxidation; 8) removing and sequestering or utilizing the carbon dioxide from the biomass; 9) a flash cooling step to prevent soot formation; 10) providing the heat required for air separation from a gas cooling process; and an efficient and cost effective method for disposal of agricultural waste.

Problems solved by technology

Many such materials are considered to be waste or are disposed of in a manner that poses environmental problems.

However, burning these residues releases CO2 and pollutants into the air, and is often prohibited.

While there is great interest in using crop residue for producing liquid fuels or power, there is as yet no generally useful or economic means for doing so.

One problem with utilizing crop residue, is that the cellulosic materials in the residuals are notoriously difficult to refine into fuels.

Thus, for example, many prior art reactors for converting biomass into fuels result in tar, ash, and soot.

Tar can negatively effect the performance of the conversion and the reactors, and generally must be removed before fuel synthesis.

In addition, other problems in converting biomass to fuels include the high energy input needed to produce synthesis gas of sufficient quality to be used for liquid fuel synthesis, and the high capital cost associated with production of O2 gas, if it is to be used in the process.

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