THE QUANTITATIVE ESTIMATION OF THE FOREST RESIDUALS AS BIOMASS FOR BIOENERGY FOR LOCAL INDUSTRY AND VILLAGES IN FOREST REGIONS OF RUSSIA
Russian state social university, Moscow state forest university –Russia
141000 Moscow region, Mytyschy, Moscow state forest university, Department of transport
Keywords: Biomass resources, bioenergy, statistical method for quantity estimation of the forest residuals, small enterprises, local industry.
Abstract: Statistical method of the quantitative estimation of forest residuals was developed, based on the line intersect method. New method based not on separate wood particle assessment but on the piles assessment of the forest residuals, which crossed the intersect line. This greatly increases the possibility of the method for estimation of forest residuals after harvesting logging operations, as for reducing of labor content and increasing of accuracy of the estimation.
A statistical method was developed for estimating the volume of forest residuals, based on the well-known Buffon's problem. The resulting formulas permit estimation of the volume of forest residuals after harvesting operations/
The most increase of using biofuel in developed countries with considerable timber resources (Sweden, Finland) is expected from forest. These are forest residuals, thin trees and stumps. Rising price on fossil fuel and improvement technology have done the fuel from forest is competitive.
Russia has all necessary conditions for development bioenergy, particularly on base of wood residuals from forest. The Development of bioenergy in Russia is held up by low internal prices on fossilized power systems and absence state political stimulations.
In Russia the most perspective raw material for bioenergy is wood raw material.
Russia, having quarter of all world wood resources, bioenergy wood share in energy is while small. This is explained by several reasons:
1. Comparatively low prices on fossil fuel and not enough state support.
2. There is no enough infrastructures, connected with bioenergy, including technologies and equipment for forest operations to produce wood fuel chips and equipment for power production.
At present time, bioenergy in Russia is developing, mainly, on three directions:
1. Using of wood waste after sawmilling, woodworking and others wood processes to produce energy for own purposes.
2. Production of the bioenergy fuel (pellets, briquettes etc.) on export.
3. Development of local energy on the base of local wood resource.
In our work, we consider the problems of local energy in Russia. Local energy directed to satisfy the needs in heating and power supply villages and objects of local industry.
The problem of local wood fuel, particularly, urgent for distant forest villages. The inhabitants of these villages are traditionally oriented for logging operations in forest to produce round timbers. However, in new economic conditions, because of high transport tariffs, round timber trade become unprofitable for distant forest regions. The solution is in development local industry, oriented on deep conversion of round timber, for example, into sawmills products. For these purpose, the development of the local energy sector is key problem. Local energy can develop on the base of local energy resources - wood fuel.
The energy for these goals can be produced by small, and even-by mini power stations with generating capacity 0.5 - 1 megawatt for the villages with population up to 1000 persons. Today such power stations rather usual, as overseas, so and beside us in country.
There are some successful examples of such projects in Russia.
As a local wood fuel for power systems can be used:
1. The forest residuals, processed into wood fuel chips.
2. The waste of sawmilling and wood processing enterprises of local industry, convert to wood fuel chips.
The advantages of local energy are:
1. Stability of the deliveries of the fuel for the power systems.
2. Stability of the prices for supplied energy.
3. Creation of new work places.
4. Increasing of the local budget because of the up growth of the local industry.
5. Solution of the ecological problems of the contamination of surrounding ambience and reduction surge of carbon dioxide.
The imperfections of the local bioenergy from forest in Russia are:
1. The high prices for work operations in forest to obtain wood fuel chips.
2. Comparatively low prices on fossil fuels.
So, we see, that using the wood fuel chips for power production, promotes economic and social development in distant forest regions. However, low prices on fossil fuels, does not stimulate the economic interest of timber industry to produce fuel from forest in Russia. The prices per round timber higher, than the price per wood fuel chips. For the logging enterprise the production of the wood fuel chips means the drawing away of the technology and workers from the main production - timber felling. Solution is in specialized small businesses with its own technology and equipment, oriented on production and supply of the wood fuel chips from the cutting areas after logging operations into the local power stations.
In this article we consider some questions concerned with work of such specialized small enterprises.
The level of profitability of the specialized small enterprises will depend on volume of the forest residuals, from technology of production the wood fuel chips, as well as will be defined by expenses on logistics chains, including transport-storage operations with chips.
Thereby, profitable work of the specialized small enterprise is connected with decision of the following problems:
1. Estimation of the real volume of forest residuals, remained on cutting area after logging operations and suitable to conversion on wood fuel chips.
2. Rational technological process.
3. Amount of equipment.
4. Cost-performance of the technology.
In this article, we pay attention only to one of the problems.
We present the statistical method of the estimation of forest residuals after harvester logging operations, including mathematical tools, allowing quantitative and qualitative estimation of the forest residuals on the base of the direct account on the cutting area.
Methods of the quantitative estimation of forest residuals we can divide into two groups:
- The forecasting methods of the estimation.
- Direct methods of the estimation on cutting area after logging operation.
The forecasting methods assign the volume of the forest residuals as a certain percent from the general volume of the forest stand depending on several factors.
Unfortunately, the forecasting methods do not show, how many forest residuals, from available on cutting area for conversion on wood fuel chips, are dirty with soil. This can do only methods of the direct estimation, applied on cutting area directly.
The most simple and efficient methods of the direct estimation in field condition are statistical methods.
Amongst such methods, for instance, method test square and the line intersection method. The line intersection method differs the simplicity.
The essence of this method in that that on cutting area is split line or several lines and are taken into account all waste, crossed by lines. For the first time this method was offered foreign researcher Warren and Olsen for estimation of the volume of forest residuals. Most full development this method has been got in works of Russian scientists Karpachev S.P., Lukjanov A. A., Scherbakov E.N. Slinchenkov A.A. .
These and others studies have shown that forest residuals powerfully different both the forms and the volumes. So, the method has a high labor-intensiveness content.
In our work, we offer the new method of estimation of the forest residuals, based on the line intersection method. The essence of the method is in estimating forest residuals not by the pieces of wood, but by piles - by heaps of forest residuals.
In basic researches the piles of forest residuals were presented in the form of circles. On a rectangular flat area of size HxL (Figure 1) n numbers of the piles of forest residuals are randomly inhere. Let us consider that all piles have, in plan, the form of circles by radius R and pile's centers have coordinates X, Y, and the law of the distribution of piles are random within the intervals [0; H], [0; L]. Through the area, a line by length 1 has been drawn. Let an angle of orientation of this line is (p and the law of the distribution of the angle is random within the interval
Figure 1: Piles of forest residuals on the flat cutting area (model)
The number of the piles on cutting area by size of LxH possible to define by formula
where M[m] -average of the number of intersects the piles with the line;
p - probability of the intersects the piles with the line.
In practice the value M[m] can be estimated by the sample mean of the number of intersects the piles with the n lines, as
Estimation of the number of the piles can be calculated from formula
The formula for the required number of the lines may be expressed as
where t - confidence index;
P - probability level, %;
Var - coefficient of variation, %.
Formula (3) allows estimate special characteristics of the piles, for instance, volume of forest residuals
where vj - volume of they pile, which was intersected by the line
Basing on the main positions of the theories of geometric probability, we carried out basic researches of the probabilistic features of the method of the line intersects for estimation of the idealizing models of the concourses of the forest residuals. Probability that the arbitrarily chosen intersect line will cross concourse of the radius R, is
where A+ - the area of the favorable events (crossing the pile with the line);
A - the full system of all events (the all positions of the pile on the cutting area).
Probability that line of the length l>2R on cutting area by size LxH will cross pile of forest residuals by radius R, is
The formula (7) inconvenient for practical use, since it is difficult to calculate the integral. If intensify condition l » 2R that indeed exists in practice, then formula (7) is converted to simple form
Formula (8) may be generalized for the cutting area of the any form.
where F - area of cutting area, m2.
Using results of the basic researches, were received graphs and made analysis of functional dependences of the required number of the lines n from radius of the piles of forest residuals R, numbers of the pile N, lengths of cutting area L, factors to accuracy P, coefficient of variation Var and the other factors (Figure 2 as an example).
Studies of the piles of forest residuals in forest have shown that radiuses of the piles satisfactory comply with the normal law of the distribution, but as for the coordinates - random law. Testing was conducted on x2 Pearson criterion on 5% significance level.
The purpose of investigations in forest was study the form of the concourses, as well as studying the laws of the distribution radius of the piles R.
The distances were measured between the piles on axis X and Y, as well as diameters of the piles R. The examples of the distribution are brought on Figure 3, 4 (as examples).
Studies of the estimation of forest residuals with the line intersect method in the forest have shown that the estimation of the volume with the analytical formula satisfactorily comply with experimental result at a significance level 5%.
Figure 2: Required number of the lines n dependence of accuracy P, %
Figure 3: Normal law of distribution of the diameters of piles on the cutting area
Figure 4: Random law of distribution of the distances between piles of the forest residuals on the cutting area (coordinate X)
1. Karpachev S. P. (2007) The quantitative estimation of the sinked timber in the rivers, Moscow, MSFU, 88 p.