CN101831337B

CN101831337B - Process technique for producing crop straw fuel

Info

Publication number: CN101831337B
Application number: CN 200910066628
Authority: CN
Inventors: 尚征
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-03-12
Filing date: 2009-03-12
Publication date: 2013-03-20
Anticipated expiration: 2029-03-12
Also published as: CN101831337A

Abstract

Under the guidance of a national policy, a technique for producing a biomass fuel by using crop straws is developed slowly so that the development of a downstream energy-consumption industrial (power generation, industries, civilian uses and the like) technique is obstructed. The straws are only used by civilian parts, and most of the straws are burnt. Mainstream techniques developed on markets comprise a biomass fuel granule granulating machine and a ring model briquetting machine, and both machines adopt a mechanical force compression technical scheme and do not solve technical problems fundamentally. The technical scheme of the invention is that: according to physical and chemical properties of the main components namely cellulose, hemicellulose and lignin of the straws, the cellulose, the hemicellulose and the lignin are separated from one another under a certain process condition; the cellulose is promoted to swell and increase an inter-felting capacity; the hemicellulose and thelignin are transformed, degraded and condensed into a phenolic aldehyde condensation compound to play a role of phenolic aldehyde resin; under the action of mechanical force, the phenolic aldehyde condensation compound is compressed and formed, and the density of a product fuel brick is between 1 and 1.4 tons/cubic meter; and each ton of the straw biomass fuel is amounted to about 0.5 ton of standard coal.

Description

Process technique for producing crop straw fuel

Technical field:

Process technique for producing crop straw fuel belongs to the biomass energy production technical field.

The energy is the important substance basis that human society is depended on for existence and development.The fossil energies such as coal, oil, Sweet natural gas have become the leading energy of productive life.At present, global annual total energy consumption has surpassed 15,000,000,000 tons of standard coals, and wherein about 90% is fossil energy.But fossil energy is the limited Nonrenewable energy resources of reserves.According to present energy consumption level, to middle period next century, the main fossil energy resource in the whole world will remain little.Simultaneously, large-scale development and utilize fossil energy to the destruction of ecotope is the irreversible deterioration problem of ecotope that the mankind that the following mankind will face jointly depend on for existence.China realizes that as fast economic growth and most populous developing country sustainable economic development are faced with the dual-pressure of more severe energy and environment.China is second-biggest-in-the-world Energy production state and country of consumption, expects the year two thousand twenty, and the primary energy source total demand will above 3,000,000,000 tons of standard coals, account for about 14% of global Energy Consumption total amount.But present Chinese total output of primary energy only reaches about 2,000,000,000 tons of standard coals, and Energy resources are poor per capita, only are 40% of world average level.In addition, the energy consumption structure of China is take coal as main, and the shared proportion of coal is near 70%.Energy structure take coal as the master is the major cause that causes environmental pollution serious.At present, Chinese CO2 emissions occupies the second place of the world, and along with rapid development of economy, the contradiction of China between the energy, environment and economy three will be more outstanding.Reduce Carbon emission, exploitation " green energy resource " has become China and has protected the fundamental state policy that ensures rapid economic development under the ecotope prerequisite that the mankind depend on for existence.

For this reason, the President Hu Jintao points out the international renewable energy source conference speech in Beijing in 2005, " strengthening the renewable energy source development and use, is to tackle the day by day serious energy and the only way of environmental problem, also is the only way that human society is realized Sustainable development." Premier Wen Jiabao explicitly points out in the second session of national energy leading group: " renewable energy source is the important strategy alternatives energy, to increasing power supply, improves energy structure, ensures energy security, and protection of the environment plays an important role.The development and use renewable energy source is the Resources for construction saving type, the grand strategy measure of friendly environment society and realization Sustainable development.”

In the face of China's primary energy source natural resources shortage and continuous rise severe true of Carbon emission, for tackling the new situations of global carbon dioxide discharge-reduction.Played " Renewable Energy Law " of formal enforcement on January 1st, 2006, national correlation department has been formulated " planning of renewable energy source Long-and Medium-term Development ", the object of planning: realize that to the year two thousand twenty renewable energy source accounts for 15% of total energy consumption, the renewable energy utilization amount will be equivalent to 600,000,000 tons of standard coals.Wherein, the biomass energy total installation of generating capacity will reach 3,000 ten thousand kilowatts, biogas year utilization will reach 440 billion cubic meters, biofuel ethanol and biofuel year utilization will reach 1,200 ten thousand tons.Meanwhile, the in succession appearance of relevant supporting policy makes the biomass energy production of China, technological development industry become the focus sunrise industry.

In the renewable energy sources such as sun power, wind energy, tidal energy, biomass, the waste of farm crop is as the biomass energy resource, it is the renewable bioenergy that is most widely used at present, its total quantity consumed is only second to coal, oil, Sweet natural gas, occupy the 4th, and in following sustainable energy system, occupy critical role.The agricultural waste material biomass energy have can store, can transportation, aboundresources, environmental influence is little, cost is low, can continuous utilization etc. characteristics be subject to the favor of countries in the world, the industrial technology development has also started climax in worldwide.

Background technology:

Because the utilization of agricultural crop straw (waste) is in for a long time nature and utilizes the stage, 30%-40% is used for cooking and heating by the peasant, and seldom a part is used to ruminate animal feed.In recent years, along with farm crop increase substantially because of the unit output that breed improvement brings, the also sharp increase of the unit output of agricultural crop straw, the peasant is for making things convenient for cultivate next year, and excessive stalk destroys by fire in the field when autumn harvest, often causes fire; The peasant is used for the stalk of cooking and heating, and near the stalk fuel wood that (especially at north cold area) is deposited in the dwelling house also usually causes fire, brings massive losses for country, society and peasant; The peasant makes the peasant can not break away from all the time the indoor pollution environment that brings because of burning straw to gather in the crops rear natural form stalk as the original energy mode of using of fuel; All the time can not break away from the heavy housework work that jade brings because of burning straw; All the time can not break away from the one hand a large amount of burning straws, and aspect developing agricultural industry (plantation, cultivation and farming industry etc.), but have to use the bunker coal of expensive, high pollution as the energy.Therefore, in the face of the problem of current existence, agricultural crop straw must be realized its high-quality, commercialization target---high-energy-density, high mass density, high commercialized degree as the utilization of biomass energy resource.

The formations such as agricultural crop straw three major polymers: cellulose, hemicellulose, xylogen, pectin substance, in every 100g straw, carbon containing 44.2g, nitrogen 0.62g, phosphorus 0.25g, the trace elements such as potassium 1.44g and calcium, magnesium, iron, sulphur, silicon.Every kilogram of about 4000 kilocalories of stalk calorific value, residual residue is plant ash after the burning, and its infertile field composition is take potassium as main, and other contains a small amount of trace element, belongs to good potash fertilizer, and its fertilizer efficiency is than compost large several times also.Large 100 times of stalk direct returning to farmland.Therefore, increasing farmers' income take agricultural crop straw (waste) as the main flow energy in the rural area, improves the rural residence environment, promotes Agricultural Industrialization Development, is the core link of resolving three rural isssues; Be Development of Organic Agriculture, recycling economy walk Sustainable Development Road must be through approach.

Up to now, China utilize the agricultural waste material biomass energy with fastest developing speed to count the biomass power generation project.Show that according to related data by the end of the year 2007, China checks and approves 81 of biomass power generation projects altogether, project in construction surpasses 40, and 17 projects wherein are constructed and put into operation.The water-cooling vibration furnace grate stalk direct combustion electricity generation boiler technology that the Technology origin of most of project is introduced in Jinan boiler group from Denmark BWE company facts have proved, this project is owing to exist problems: introducing technology causes cost too high, invests excessive; The stalk energy density is too small to cause transportation, storage cost too high; The seasonality production of stalk and load in bulk, loose deposit, the loose burning cause fuel to be difficult to the fatal problems such as stable market supply, and the tempo of straw power generation industry is obstructed.

In addition, also be in incubation period in the development aspect the utilisation technology of straw biomass Energy resources, stalk is used for by vast rural area as the biomass energy resource that cooking and winter heating are existing to exceed history in thousand, but because it is in the prime energy utilization of resources and adopts combustion technology and the equipment stage that falls behind, the thermo-efficiency of this utilization of resources is in 15% for a long time---about 20%.

For this reason, at present can be take agricultural waste material as the biomass energy resource, produce high-quality commercial biomass fuel, to be applicable to biomass fermentation electric boiler, industry (hot water, steam) boiler, civil heating and cooking boiler etc., it is the developing direction of the huge biomass energy utilization of resources of China.Therefore, the exploitation of this practicality technology is the technology public relations focus of all multiple enterprises.Up to now, domestic have three classes in the production technology take agricultural waste material as raw material production biomass (briquetting) fuel:

1, application system carbon rod-made machine compacting biomass fuel, technical superiority is: fuel energy density is large, conveniently stores, transports and be applicable to native kitchen range burning among the people; Shortcoming is: use raw material and can only add 30% crop material, all the other 70% must have the development of new of needs boiler take wood chip as raw material, be difficult to crop genetic resource utilize aspect and be applicable to the development of existing combustion equipment aspect.

2, biomass fuel pellet tablets press, the production diameter is 8mm, the grain biomass fuel of the about 1-2cm of length.Technical superiority is: the large technical superiority of fuel energy density is: fuel energy density is large, can utilize agricultural crop straw to be raw material, convenient storage, transportation; Shortcoming is: need the development of new special combustion device, be difficult to be applicable to development aspect the existing combustion equipment.

3, use herbage (stalk) foragizer, the compacting biomass fuel take crop material as raw material.Technical superiority is: fuel energy density is larger, can utilize agricultural crop straw to be raw material; Be applicable to native kitchen range among the people and part combustion of industrial boiler, larger development space is especially arranged aspect fuel for power generation; Shortcoming is: because energy density only can reach 0.7-0.8 kilogram/cubic centimetre, because the density less, fuel brick can scatter after the moisture absorption, is unfavorable for standing storage.

Summary of the invention:

The present invention is process technique for producing crop straw fuel, is a kind of production technology that becomes biomass fuel take agricultural crop straw (agricultural waste material) as Raw material processing.At first, with the platy shaped particle of crops stalk crushing one-tenth less than 1 centimetre, part Mierocrystalline cellulose, hemicellulose, xylogen and pectin substance are separated; Then, impel straw Stalk softening under certain temperature, humidity condition, this is conducive to the further separation of fiber.This process is utilized hemicellulose to be easy to hydrolysis and is made Mierocrystalline cellulose be easy to swollen, be conducive to enlarge the Mierocrystalline cellulose specific surface area, increases the quantity of free hydroxyl group, is easy to hydrogen bonded, the fortifying fibre felt properties.The 3rd, material is entered under the processing condition between the 17-20% 150-180 ℃ and water content heats and the ring mould briquettor of milling apparatus grinds and condensation, process of lapping makes Mierocrystalline cellulose, hemicellulose further separates with lignin, but the hemicellulose Partial Conversion is furfural simultaneously, lignin then Partial digestion is aldehydes matter, at high temperature, suitably under humidity and the pressure condition, the two condensation forms phenolic condensation compound, play the effect of resol, Mierocrystalline cellulose is compressed into has certain density, intensity and the patch fuel with anti-deliquescence ability, the fuel brick specification is different different because of briquetting press ring mould specification, fuel brick quality: density 1000 kilograms per cubic meter---1400 kilograms per cubic meter; Calorific value: 3500---4200 kilocalories/kilogram;

Temperature and the water ratio most critical of this technological process control material, the poor heat resistance of hemicellulose, temperature drift causes fuel to produce the caramel piece, thus temperature meeting on the low side affect hemicellulose and lignin formation phenolic condensation compound affects fuel mass; Because hemicellulose can not form crystallizing field, water molecules enters easily, therefore the water-absorbent of hemicellulose and swollen degree are all high than Mierocrystalline cellulose, the higher hemicellulose that exceeds of material moisture moistens the required moisture that rises, exceed moisture and can in the compression process of High Temperature High Pressure, produce water vapor, the fuel brick of compression is popped when extruding the ring mould, when moisture is lower than hemicellulose profit and rises by required moisture in the material, hemicellulose and lignin meeting coking, be difficult to form condenses, Mierocrystalline cellulose also loses felt power because fully not moistening to rise, and it is Powdered to cause fuel brick to present, and finally still affects the product compressed moulding.

Embodiment:

Implementation technique is: agricultural crop straw---pulverizes and---carries---oven dry---wind that disappears, dedusting------grinding---compression---cooling---packing that control is wet, heated.The agricultural crop straw raw material adopts automatic charging, feed system; Pulverize to adopt the screen cloth feed grinder is arranged; Handling equipment adopts worm conveyor; Airflow dryer is adopted in oven dry, and thermal source adopts biomass fuel hot air stove; The elegance that disappears cyclonic separator, bag dust filter is adopted in dedusting; The wet reverse feedback humidification Controlling System that is consisted of by humidity sensor, transmitter, micro pressure water pump etc. that adopts of control; The ring mould briquettor of heat, grinding, compression process selecting to have warming apparatus; Selection by winnowing cooling mesh conveyer transfer roller is adopted in cooling; Packing adopts automatic weighing sealing machine (rich and influential family's supply of material is taked to fall apart and deposited, loads in bulk, need not packing).

Claims

1. process technique for producing crop straw fuel, it is characterized in that: because agricultural crop straw three major polymers: cellulose, hemicellulose and lignin form, after being risen, the Mierocrystalline cellulose profit increases felt power, the hemicellulose Partial Conversion is furfural, lignin then Partial digestion is aldehydes matter, the two condensation forms phenolic condensation compound, plays resol, in the moulding of mechanical force lower compression;

The rights protection scope:

1., technological process: the agricultural crop straw-pulverize-carry-dry-wind that disappears, dedusting-control are wet, are heated-grind-compress-cool off-pack;

2., processing condition: at first, with pulverizer process stream is carried out pre-treatment, soon it is ground into the fragment less than 1 centimetre; Secondly, material is sent into dryer heat and slough free water content, make simultaneously material softening; The 3rd, the wind that disappears, dedusting; The 4th, to make the material humidification arrive water content between 17-20%, send into and heat and the ring mould briquettor of milling apparatus, make material under 150-180 ℃ processing condition, advance to grind, Mierocrystalline cellulose, hemicellulose and lignin are further separated, simultaneously, the felt power of fortifying fibre element and promotion phenolic condensation compound form; The 5th, the patch fuel that under the mechanical force that reaches the ring mould briquettor under said temperature, the humidity condition, makes material compression become to have certain density, intensity and have anti-deliquescence ability; At last, in technological process, the negative feedback control system that employing is made of temperature sensor, humidity sensor, transmitter, heating and moistening power element is realized temperature, the humidity control in the technique;

3., product feature: fuel brick profile and specification are different different because of briquetting press ring mould specification; Fuel brick density because of due to the behavioral characteristics of technique in 1000 kilograms per cubic meter-1400 kilograms per cubic meter; Calorific value because of the raw material difference greatly about 3500-4200 kilocalorie/kilogram.