Aggregates of Cleaned Low Energy Coal Fines and Beneficiated Organic-Carbon-Containng Feedstock

Abstract

A processed biomass / coal blended compact aggregate composition made with a blending sub-system from a processed organic-carbon-containing feedstock made with a beneficiation sub-system and low energy coal is described. Renewable biomass feedstock passed through a beneficiation sub-system to produce a processed biomass with an energy density of at least 17 MMBTU / ton (19 GJ / MT), a water content of below at least 20 wt % and an intracellular water-soluble salt that is at least 60% below that of unprocessed organic-carbon-containing feedstock on a dry basis. Low energy un-cleaned coal is sized and passed through a coal cleaning sub-system to result in cleaned low energy coal having an energy density of less than 21 MMBTU / ton (24 GJ / MT) and a content of sulfur that is at least 50 wt % below that of the content of sulfur in the coal before it passed through the coal cleaning sub-system. The processed feedstock is sized and blended with the cleaned low energy coal in a blending sub-system to form a blended aggregate that comprises at least 10 wt % of the cleaned low energy coal and at least 10 wt % of the processed biomass.

Description

FIELD OF THE INVENTION[0001]The present invention relates generally to the production of biomass and coal aggregates.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 by-products suitable for transportation and / or heating is an important factor in meeting the ever-increasing ...

AI Technical Summary

Benefits of technology

The invention is a new type of biomass / coal blended aggregate that solves the problem of low energy density in low energy coal and biomass blends. It allows for the use of low energy coal fines that are currently being stockpiled due to their potential explosive nature. The invention results in aggregates with improved energy density and sulfur content, and can use a wide variety of renewable organic-carbon-containing feedstock in a cost-efficient manner. The process also reduces the adverse effects of water-soluble salts and leads to a reduction in energy needed to remove water from the feedstock. Overall, the invention provides a way to effectively use low energy coal and biomass in various applications.

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 million British thermal units per ton (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, coal substitute, or binders for the making of coal aggregates from coal fines, 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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