Oxygen-Deficient Thermally Produced Processed Biochar from Beneficiated Organic-Carbon-Containing Feedstock

Abstract

A renewable processed biochar composition made with an oxygen-deficient thermal sub-system from a processed organic-carbon-containing feedstock made with a beneficiation sub-system is described. Renewable biomass feedstock passed through a beneficiation sub-system to reduce water content to below at least 20 wt % and water-soluble salt reduction of at least 60% from that of unprocessed organic-carbon-containing feedstock on a dry basis. The processed feedstock is introduced into an oxygen-deficient thermal sub-system to result in renewable processed biochar having an energy density of at least 17 MMBTU / ton (20 GJ / MT) a water content of less than 10 wt %, and water-soluble salt that is decreased by at least 60 wt % on a dry basis from that of the unprocessed organic-carbon-containing feedstock.

Description

FIELD OF THE INVENTION[0001]The present invention relates generally to the production of solid char fuel from an organic-carbon-containing feedstock.BACKGROUND OF THE INVENTION[0002]The vast majority of fuels are distilled from crude oil or obtained from natural gas pumped from limited underground reserves, or mined from coal. As the earth's crude oil supplies become more difficult and expensive to collect and there are growing concerns about the environmental effects of coal other than clean anthracite coal, the world-wide demand for energy is simultaneously growing. Over the next ten years, depletion of the remaining world's easily accessible crude oil reserves, natural gas reserves, and low-sulfur bituminous coal reserves will lead to a significant increase in cost for fuel obtained from crude oil, natural gas, and coal.[0003]The search to find processes that can efficiently convert biomass to fuels and byproducts suitable for transportation and / or heating is an important factor ...

AI Technical Summary

Benefits of technology

The invention is a processed biochar that can be used as a substitute for coal in devices that generate heat. The low salt content of the processed biochar reduces corrosive wear and maintenance cleaning of the devices. The uniform low water content and energy density of the biochar make it suitable for a wide variety of renewable organic-carbon-containing feedstocks, which can be used in a cost-efficient manner. The process reduces the amount of water-soluble salts and the energy needed to remove water from the feedstock is significantly less than for known processes. The cost per weight of the beneficiated feedstock is reduced by at least 60% of the cost to prepare it for use in fuel making operations.

Problems solved by technology

As the earth's crude oil supplies become more difficult and expensive to collect and there are growing concerns about the environmental effects of coal other than clean anthracite coal, the world-wide demand for energy is simultaneously growing.

Over the next ten years, depletion of the remaining world's easily accessible crude oil reserves, natural gas reserves, and low-sulfur bituminous coal reserves will lead to a significant increase in cost for fuel obtained from crude oil, natural gas, and coal.

However, this feedstock typically contains too much water and contaminants such as water-soluble salts to make it an economical alternative to common sources of fuel such as coal, petroleum, or natural gas.

And, even if the plants were sun or kiln-dried, the natural and man-made chemicals and water-soluble salts that remain in the plant cells combine to create corrosion and disruptive glazes in furnaces.

Also, the remaining moisture lowers the heat-producing MMBTU per ton energy density of the feedstock thus limiting a furnace's efficiency.

Thus, municipal waste facilities that process organic-carbon-containing feedstock, a broader class of feedstock that includes materials that contain plant cells, generally operate in an energy deficient manner that costs municipalities money.

Similarly, the energy needed to process agricultural waste, also included under the general term of organic-carbon-containing feedstock, for the waste to be an effective substitute for coal or petroleum are not commercial without some sort of governmental subsidies and generally contain unsatisfactory levels of either or both water or water-soluble salts.

The cost to suitably transport and / or prepare such feedstock in a large enough volume to be commercially successful is expensive and currently uneconomical.

Also, the suitable plant-cell-containing feedstock that is available in sufficient volume to be commercially useful generally has water-soluble salt contents that result in adverse fouling and contamination scenarios with conventional processes.

Attempts have been made to prepare organic-carbon-containing feedstock as a solid renewable fuel or coal substitute, but these have not been economically viable as they generally contain water-soluble salts that can contribute to corrosion, fouling, and slagging in combustion equipment, and have high water content that reduces the energy density to well below that of coal in large part because of the retained moisture.

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