Method for high energy density biomass-water slurry

Abstract

An energy efficient process for converting biomass into a higher carbon content, high energy density slurry. Water and biomass are mixed at a temperature and under a pressure that are much lower used in than prior processes, but under a non-oxidative gas, which enables a stable slurry to be obtained containing up to 60% solids, about 38% carbon by weight. The temperature is nominally about 200° C. under non-oxidative gas pressure of about 150 psi, conditions that are substantially less stringent than those required by the prior art.

Description

FIELD OF THE INVENTION[0001]The field of the invention is the synthesis of transportation fuel from carbonaceous feed stocks.BACKGROUND OF THE INVENTION[0002]There is a need to identify new sources of chemical energy and methods for its conversion into alternative transportation fuels, driven by many concerns including environmental, health, safety issues, and the inevitable future scarcity of petroleum-based fuel supplies. The number of internal combustion engine fueled vehicles worldwide continues to grow, particularly in the midrange of developing countries. The worldwide vehicle population outside the U.S., which mainly uses diesel fuel, is growing faster than inside the U.S. This situation may change as more fuel-efficient vehicles, using hybrid and / or diesel engine technologies, are introduced to reduce both fuel consumption and overall emissions. Since the resources for the production of petroleum-based fuels are being depleted, dependency on petroleum will become a major pro...

AI Technical Summary

Benefits of technology

[0018]The present invention provides an energy efficient process for converting biomass into a higher carbon content, high energy density slurry. In particular, water and biomass are mixed at a temperature and under a pressure that are much lower used in than prior processes, but under nitrogen, which enables a stable slurry to be obtained containing up to 60% solids, which is about 38% carbon by weight. While ranges will be given in the detailed description, the temperature is nominally about 200° C. under non-oxidative gas pressure of about 150 psi, conditions that are substantially less stringent than those required by the prior art.

Problems solved by technology

Since the resources for the production of petroleum-based fuels are being depleted, dependency on petroleum will become a major problem unless non-petroleum alternative fuels, in particular clean-burning synthetic diesel fuels, are developed.

Moreover, normal combustion of petroleum-based fuels in conventional engines can cause serious environmental pollution unless strict methods of exhaust emission control are used.

Such a process allows for the application of current state-of-art engine exhaust after-treatment methods for NOx reduction, removal of toxic particulates present in diesel engine exhaust, and the reduction of normal combustion product pollutants, currently accomplished by catalysts that are poisoned quickly by any sulfur present, as is the case in ordinary stocks of petroleum derived diesel fuel, reducing the catalyst efficiency.

These waste sources of carbonaceous material are not the only sources available.

Unfortunately, open burning of biomass waste to obtain energy and heat is not a clean and efficient method to utilize the calorific value.

A number of processes exist to convert coal and other carbonaceous materials to clean-burning transportation fuels, but they tend to be too expensive to compete on the market with petroleum-based fuels, or they produce volatile fuels, such as methanol and ethanol that have vapor pressure values too high for use in high pollution areas, such as the Southern California air-basin, without legislative exemption from clean air regulations.

This high hygroscopicity of biomass is generally why biomass slurries are not readily produced with a high carbon content.

However, it has to be carried out under high energy conditions.

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