TITLE: PROCESS FOR PREPARING TORREFIED BIOMASS MATERIAL USING A
COMBUSTIBLE LIQUID
TECHNICAL FIELD
The การเปิดเผยนี้ pertains to torrefied biomass and/or biosolids, and in 5 particular, to a torrefied densified biomass and/or torrefied densified biosolid ซึ่งประกอบรวมด้วย a
combustible liquid and processes for preparing such torrefied densified biomass and/or
biosolids using a combustible liquid.
BACKGROUND
Biomass and biosolids are becoming important sources of energy as the supply of 10 fossil fuels decreases. Burning of petroleum, coal and other fossil fuels also leads to
pollutants and greenhouse gases being released into the air and water. Biomass and biosolids
are renewable, produce significantly fewer greenhouse gases than fossil fuels and are widely
available. Raw biomass and biosolids, however, generally have a low density resulting in
inefficient storage and transportation. The low energy densities and higher moisture contents 15 of raw biomass and biosolids also hampers the widespread use of raw biomass and biosolids
as a source of thermal energy or as a coal replacement.
Torrefaction of raw biomass and biosolids has been developed recently to turn the
biomass and biosolids into a charcoal-like state by slow-heating the biomass and biosolids in
an oxygen-free or low-oxygen environment to a maximum temperature of about 300°C. The 20 lack of oxygen prevents the biomass and/or biosolids from burning, and instead, the material
is torrefied. Slow-heating biomass and biosolids also leads to loss of mass due to the volatile
organic compounds (VOCs) within the raw biomass and biosolids being gassified.
Torrefaction also causes chemical changes to the cellular structures of the material, resulting
in a partial loss of mass and a loss in mechanical strength and elasticity. Torrefaction, 25 therefore, also produces a product that has increased friability and grindability. Furthermore,
torrefied material is hydrophobic and therefore, stays dry and is insensitive to atmospheric
humidity. This reduces the risk of rotting, overheating, and auto-ignition of the materials
when stored.
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Prior art torrefaction processes generally involve one of high-pressure steam, high temperature inert gas or superheated steam in the heat treatment processes. Other torrefaction processes using gas or pressure or vacuum methods may also be used. Most of these prior
technologies, however, fail to efficiently and practically convert biomass into torrefied wood 5 in a simple, easy, quick, practical, safe, uniform and economic way. In particular, using any
type of inert gas or steam involves large containment systems with large amounts of surface
area, high equipment costs, high energy costs, slow treatment rates, and low overall operating
efficiencies with resultant high production costs. The systems and equipment are complex
and large for containing the inert gas or steam heat transfer medium, and often require 10 heavyweight materials given the high operating pressures required with steam. Furthermore,
these systems often require more than an hour to torrefy biomass. Consequently, the prior
technologies also have challenges with scalability.
Recent torrefaction processes have also used bio-liquids (such as, vegetable oils,
soybean oils, canola oils or animal tallow), paraffinic hydrocarbons, oil, molten salts or 15 paraffin, to heat and torrefy biomass. Some of these technologies, however, involve
intricately designed housings for holding the liquids and torrefying the biomass, and require the biomass to pass through a plurality of pools, rivers or liquid compartments holding the liquids during the torrefaction process. These processes, therefore, may require additional
engineering efforts, complicated designs and large volumes of the torrefying liquids. 20 Moreover, these processes often involve a pre-heating stage and/or a drying stage prior to the
torrefaction treatment, thus, being costly to operate and time-consuming.
SUMMARY
The exemplary embodiments of the การเปิดเผยนี้ generally pertain to a torrefied
densified biomass and/or biosolid ซึ่งประกอบรวมด้วย a combustible liquid and processes for 25 preparing the torrefied densified biomass and/or biosolid using a combustible liquid
exemplified by hydrocarbons, such as plant-derived oils, marine-derived oils, animal-derived
oils, petroleum products and bitumen-based products.
An exemplary process for preparing a torrefied densified biomass and/or torrefied
densified biosolids of the การเปิดเผยนี้ is disclosed herein, in which a combustible liquid 30 is used for torrefying a densified biomass material and/or densified biosolid material. The
exemplary process may ประกอบรวมด้วย one of two starting materials: (i) the initial starting material
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may be raw biomass and/or biosolids that undergo densification prior to heating in the combustible liquid; or (ii) the initial starting material