Fully Closed, Zero Discharge, Clean Oxidizing Pulping Technology and Process

Abstract

The aim of the present invention is to provide a close-loop, zero discharge and clean oxidation pulping method and technology. In accordance with present invention, it takes advantage of active oxygen free radical generated by reduction reaction of molecular oxygen in process reactor to transform and separate lignin to change chromophoric group in the intercellular space and obtain paper pulp. The conventional pulping technologies which use harmful polluting chemicals such as acid, alkaline, chlorine, anthraquinone and so on are basically changed in the present invention. The cooking and bleaching process, generating severe pollution, can be avoided. The abundant yearly grown fiber materials can be utilized in this process, and water and energy can be saved. The present invention can cut down production cost and have excellent social, economic and environmental performance.

Description

FIELD OF THE INVENTION [0001] The invention relates to a process for a fully closed, zero discharge, clean oxidizing pulping technology and process. It is practically a process that involves a method with close-loop, self-cycling, non-acid, non-alkali, non-chlorine, non-anthraquinone, non-cooking, non-bleaching, non-draining and non-pollution. BACKGROUND OF THE INVENTION [0002] Short supply of papermaking materials is a problem faced by the pulping & papermaking in a long term and occurs not in a single district but in worldwide. Forest acts as the lung of earth that can absorb carbon dioxide and produce oxygen in addition to the effect on the conservation water resources, prevention of soil erosion, and adjustment of climate. And it has ecological and economic value. However, it is now decreasing at a rate of 700×108 m2 yearly and tropical rain forest is being reduced at a rate of 50×104 m2 per minute. If the illegal ruinous exploitation is not strictly restricted, with the increas...

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Benefits of technology

[0029] In accordance with the present invention, it takes advantage of active oxygen free radicals generated by oxidation-reduction reaction of molecular oxygen in reactor to transform and separate lignin, and to change chromophoric group in the intercellular space and obtain paper pulp. The conventional pulping technologies that use harmful polluting chemicals such as acid, alkaline, chlorine, anthraquinone and so on are basically changed in the present invention. The cooking and bleaching process, generating severe pollution, can be avoided. The abundant yearly grown fiber materials can be utilized in this process and water and energy can be saved. As a result, the cost of production can be saved.

[0041] In accordance with the invention, the metal ions are selected from Mg2+, Fe2+, Mn2+, Cu2+, Al3+, Zn2+, Si2+ and two or multi-kinds of their compounds and the ions are in the form of salt such as FeSO4, MgCO3 etc. The metallic ion ligands is selected from DMD, DTPA, EDTA, alkyl-sulfonic acid sodium, poly-oxyethyl-enabkylether and two or multi-kinds of their compounds. Together with the metal ion, the metallic ion ligand, hyperoxidized anion free radical (O2− / HOO.) and H2O2, they form a functional cellulose protection system which can not only protect cellulose but also get rid of silicon.

[0057] Comparing with current technology, method of the invention has advantages as follows: It is practically a process which involves a method with close-loop, self-cycling, non-acid, non-alkali, non-chlorine, non-anthraquinone, non-cooking, non-bleaching, non-draining and non-pollution. The method has characters of saving energy, saving water and clean pulping and it solves pollution of papermaking completely, utilizes the resource of agriculture and forest, and protects the environment. In accordance with the present invention, the fully closed, self-cycling, zero discharge refers to: All water in the process from the pretreatment of raw materials till the delivery of it to the oxidation reactor is divided into two parts to accomplish the self-cycling in the process. One is the water from the process of materials cleaning pretreatment. It is purified by centrifugal cleaning and the solid sediments in it are taken away. The pulps are sent to the common beating process. Water generated in the process is cycled into purification pool. 0.1%-0.15% ozonizer and acticarbon nutsch filter are installed in the purification pool to decolor the water. The water contains oxygen free radical and it is pumped into the cycling water system The other is the water from the oxidizing process. After cleaned with centrifugal cleaner and then is concentrated with common decker, the pulp is sent to the tank for papermaking. The produced water is filtrated and placed in the water-purifying tank for self-cycling. The purified water is pumped into materials cleaning system, oxygen dipping system, oxygen grinding system and filtrating system for recycling use. No any gas or black liquor is drained in the process. The mixed solid residue only occupied 12%-22% of the materials. This process is pollution-free and the residue can be sent to bio-oxidation treatment tank.

Problems solved by technology

Short supply of papermaking materials is a problem faced by the pulping & papermaking in a long term and occurs not in a single district but in worldwide.

If the illegal ruinous exploitation is not strictly restricted, with the increasing of the whole world population, human beings may have to face the dilemma of non-adequate oxygen to breathe 40 years later.

The traditional process has seriously impacted the environment that humankind relies for existence.

Nevertheless, 91% ClO2 may produce dioxine and other organic compounds, and the remained 9% Cl2 is discharged to the atmosphere, which harm the environment that human beings rely on.

But it was not industrialized due to the great loss of cellulose, high energy and water consumption and high production cost.

Until March, 2002, there are no any plant can finish degradation of lignin without acid, alkali and no any plant puts down acid, alkali and chlorine completely, which illustrate the pollution problem has not been thoroughly resolved in these patents.

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