HU208819B - Process for utilization of the remainder of furfurole-production making briquette - Google Patents

Abstract

Bricks, prepd. from the partly dried waste (5-25% water) at a pressure of 800 bar and 40-100 deg.C, are used in burning of organic materials, e.g. corn cobs and leaf wood.

Description

The present invention relates to a process for the environmentally friendly utilization of furfural residues by briquetting.

One of the most important characteristics of pentosan-containing plant materials in furfural production is the pentosan content. In practice, wood chips, corn cobs, bagasse and kernels are used as starting materials. The pentosan content of the raw materials ranges from 20-30%, which theoretically 10%, in practice 58% is converted to the intermediate product, furfural. In addition to the semi-product, furfural production produces about 15-20 kinds of organic compounds, some of which (eg acetic acid, formic acid and methanol) are removed by the vapor phase and the other (eg acetic acid, resin) is removed by the reactor.

Common to the processes used in the production of furfural are the low conversion of pentoses to furfural and the resulting high consumption of raw materials (15-30 tons of raw material / tonne of furfural). Due to the high consumption of raw materials, the cost of the raw material may represent 60-70% of the cost of furfural. It is clear from the foregoing that the most feasible way to reduce the cost of furfural is to convert the residue into a valuable product.

Another incentive for processing the residue into a valuable, usable product is environmental protection. Depending on their capacity, the furfural production plants emit between 60 and 200,000 tonnes of residual material per year, which is a potential pollutant.

The residue contains significant amounts of acetic acid and formic acid which, when stored outdoors, enter the soil and cause acidification. Not only do the acids in the soil reduce the fertility of the land, they also contaminate the drinking water of the surrounding area when they enter the groundwater.

For the above reasons, several residue processing processes have been developed.

For example, it is possible to burn the residual material from the reactor in a boiler and to produce steam with the energy released. However, due to the specific characteristics of the residues to be burned, a special boiler is required for incineration, which represents a significant investment cost. Also of great concern are the high moisture content of the residue (40-50%), the small particle size and the organic compounds leaving the combustion product which cause corrosion. With this process, only valuable energy can be obtained for industrial plants, because by the nature of the boilers, only an incinerator capable of burning residual material with a mass flow rate of 5-8 kg / s is economical.

Further, it is known, for example, from the Hungarian patent specification 111399 to provide a granular product which can be used as a carrier from the furfural residues. Depending on the area of application, the granulate should have a high specific surface area, a particle size of 0.2-1 mm and a relatively low bulk density (about 4-500 g / l). However, due to the special properties of the carrier material, it cannot be used, for example, as a high input fuel. A further disadvantage of the solution disclosed in Hungarian Patent No. Alii 399 is that the use of a binder is mandatory, in addition, at a temperature of 360 ° C, at which temperature the natural binders present in the residue are sufficient. A similar solution is further described in European Publication No. 0092981, however, for the manufacture of fibreboard and the use of additional adhesive.

The briquetting of the dried residue by itself has thus far not been solved, and in each case an additive (such as bitumen or waste oil) has been used. Different percentages of adhesives were used, which resulted in additional costs (material and handling costs). The use of binders is unfavorable both from a combustion technology and environmental point of view, due to the soot of the combustion equipment and the strong smoke formation.

There is a general societal need to utilize waste materials, transform them into valuable products and utilize them as energy carriers. Thus, there has been a recent increase in demand for energy carriers and fuels suitable for residential use, can be easily burned in domestic heating systems and contain low levels of environmental pollutants, such as sulfur, at appropriate heating values.

The use of furfural residues as a fuel has been addressed for many years. However, high humidity and dusty conditions make recovery difficult and incineration can only be carried out on a large scale with significant investment costs.

It is an object of the present invention to provide a process which, without the use of a binder, produces a finished product of high quality which does not contain soot and does not contain pollutants such as the combustion product of briquettes produced to date.

The present invention is based on the discovery that the furfural residues having a moisture content of 40-50% by weight are dried to a moisture content of 5-25% by weight, preferably 7-15% by weight, in an inlet air dryer, preferably 400-600 ° C, and the resulting dried residue is obtained. by itself, without the use of a binder, briquetted in a press machine having a head pressure of at least 80 MPa, the temperature of which is adjusted to 40-100 ° C, preferably 50-80 ° C by cooling, preferably water cooling, to obtain a product, which has advantageous properties.

Any furfural residues may be used as starting materials in the process of the invention, but residues obtained from the processing of corn cobs and / or corn stalk or deciduous wood are preferred.

The briquette obtained by the process of the invention is mecha2

EN 208 819 Β Optical firing strength and dimensional stability. It does not swell or dust during combustion, gradually reducing its size. As long as it contains combustible material, its mechanical strength remains. The product is proportionally shaped. Due to the nature of the raw material, briquettes do not release pollutants such as sulfur dioxide during combustion.

The following examples are intended to illustrate the invention.

Example 1

In a rotary dryer at 450 ° C, the furfural residue with a starting moisture content of 45% is dried in a rotary drum to a moisture content of 17% and is used for corn cobs.

It was obtained by autocatalytic hydrolysis at 1.2 MPa and 180-200 ° C to obtain furfural. The head temperature of a mechanical piston press with a mass flow rate of 0.111 kg / s and a head pressure of 100 MPa is adjusted to 60-65 ° C by water cooling (operating temperature). The dried residue is continuously added to the press and the head temperature of the press is monitored. Test results for the product obtained: combustion heat 18723 kJ / kg calorific value 17589 kJ / kg ash 6.15% moisture content 9.54% characteristic: proportionately shaped

Example 2

In a rotary dryer at 400 ° C in a rotary drum, a furfural residue of 40% by weight obtained from the hydrolysis of oak as described in Example 1 is dried to a moisture content of 7% by weight. The head temperature of the press machine described in the previous example is adjusted to 45-50 ° C by water cooling. Test results of the product obtained:

combustion heat 18527 kJ / kg calorific value 17446 kJ / kg ash 9.21% humidity 7.25% characteristic: proportionately shaped

Comparative examples

Example 3

The furfural production residue of Example 1 having an initial moisture content of 45% is dried in a rotary dryer at 400 ° C in a rotary dryer. The head temperature of the press machine described in Example 1 cannot be adjusted so that the mechanical strength of the resulting briquette is adequate. The briquette is disintegrated by heat (before the start of combustion).

Example 4

The dried residue obtained as described in Example 2 is added to the press. The head temperature of the press is 110 ° C, because, contrary to the invention, no cooling is used. The press is burned and continuous production cannot be ensured.

Claims (5)

PATIENT INDIVIDUAL POINTS 1. A process for the environmentally friendly use of a furfural production residue by briquetting, wherein a 40-50 wt. is set to. Process according to claim 1, characterized in that the residue obtained when processing corn cobs and / or corn stalks or deciduous trees is dried. Method according to claim 1 or 2, characterized in that it is dried by a drying apparatus operating at an inlet air temperature of 400-600 ° C. A process according to claim 3, wherein the residue is dried to a moisture content of 7-15% by weight. Method according to one of the preceding claims, characterized in that the head temperature of the press machine is adjusted to 50-80 ° C.