In 2023, with the continuous release of policies to reduce carbon emissions and energy consumption, coupled with the continuous high level of coal, cement companies, which are large coal users, have begun to lay out the "RDF SRF alternative fuel" marketOn the one hand, it is also an important measure for cement companies to achieve the goals of carbon peak and carbon emission reduction.
A cement company in Guangdong Province purchased a large amount of SRF alternative fuels prepared from waste textiles in the local area, and carried out exploratory practice for practical application.
The cement company has set up a simple waste spinning SRF alternative fuel conveying and feeding system (as shown in the figure below), the waste spinning SRF is fed through the spiral reamer frequency conversion speed regulation, and after being lifted from the hoist to the preheater, it is fed into the decomposition furnace through the conveying belt and pneumatic airlock valve.
The test on the use of alternative fuels for waste spinning SRF was carried out on the 5 000 t D production line (see Table 1 for the test data).2.3) The problems existing in the test process and the impact on production are:
2) The bulk density of waste spinning SRF is small, the conveying capacity of the configured hoist is insufficient, and the average usage of waste spinning SRF is 745 t/d；
3) The lifting height of the configured hoist is insufficient, and the feeding port of the waste spinning SRF is located below the mouth of the tertiary air into the decomposition furnace, which is not conducive to the dispersion of the waste spinning SRF in the decomposition furnace and the mixing with the tertiary air. After entering the decomposition furnace, part of the waste spinning SRF bonded with the raw meal powder under heating and fell into the smoke chamber, which affected the working conditions of the kiln, resulting in a high CO concentration at the outlet of the decomposition furnace and a decrease of 65 t d in the kiln output. Affected by the above, the standard coal consumption decreased by 5 after the use of waste spinning SRF17 kg t, according to the calculation, the calorific value conversion efficiency of waste spinning SRF is about 65%.
The cement enterprise was subsequently controlledWaste spinning SRF particle size 200 mm, improve the capacity of the spiral reamer and hoist, and raise the feed point of the waste spinning SRF, the waste spinning SRF usage is increased to about 120 t d,Standard coal consumption decreased by 90 kg t, the calorific value conversion efficiency of waste spinning SRF is increased by about 70%.
Test results and discussion
The dry basis calorific value of SRF alternative fuel prepared from waste spinning is 5 000 4Around 18 kJ kgIf it is adopted on a large scale, it can effectively reduce the consumption of standard coal
The chemical composition of different waste spinning is quite different, and it is possible to purchase SRF alternative fuelsOpt for high-quality SRF alternative fuels with lower CL content after passing through screening equipmentIt is necessary to pay attention to the changes in the content of MGO, SO3 and Cl- in the process of use
The bulk density of waste spinning SRF alternative fuel is small, and a larger conveying and feeding system needs to be configured
The size of the SRF alternative fuel is important, and it is recommended to control the particle size of the SRF alternative fuel to 50 200 mm,Reduce feeding interruptions caused by winding and rack blockage during conveying and feeding;
When the consumption of waste spinning SRF increases to more than 100 t d, the feeding points should be arranged at multiple points and configured above the tertiary air to ensure their dispersion and combustion effect in the decomposition furnace, which can greatly improve the thermal conversion efficiency of SRF alternative fuels.
From the test results, we can tentatively define high-quality alternative fuels:Size 200 mm (or less) with low CL content and low impurity content；So how should high-quality SRF alternative fuels be prepared?
Zhongshan SRED Environmental Protection Technology has been deeply involved in the solid waste treatment industry for more than 10 years, and has an overall solution for SRF alternative fuel preparation in the fields of domestic waste, bulky garbage, paper mill waste, decoration waste, general industrial solid waste, waste tires, agricultural and forestry waste, etc. For example, the above-mentioned general industrial solid waste RDF SRF alternative fuel preparation system for the preparation of SRF from waste spinning:
SRred integrates the cutting-edge solid waste treatment technology concept of Germany, and has launched an integrated and modular comprehensive treatment system that meets the characteristics of various general industrial solid wastes. Passed".Two-stage crushing + magnetic separation + air separation + sorting + dust removalThe obtained SRF alternative fuel has a great improvement in the discharge size, iron removal (Cl) rate, and impurity removal rate, the heat loss coefficient is lower, and the average combustion calorific value of the alternative fuel has reached more than 5000 kcal.
In terms of the size of the discharge, the service settings of Sred are more user-friendly, and according to the needs of customers, they can be usedThe discharge size level is divided into 30mm, 50mm, 80mm, and 120mm.
SRF's RDF SRF alternative fuel preparation technology has always been a benchmark in the domestic solid waste treatment industry, and has participated in the drafting of four group standards, namely "Definition and Classification of Solid Alternative Fuels", "Technical Specifications for the Preparation of Solid Alternative Fuels", "Solid Alternative Fuels for Cement Kilns" and "Solid Alternative Fuels for Thermal Power Generation" formulated by the China Industrial Cooperation Association, contributing to the development process of domestic alternative fuel standardization.
At present, Srude Environmental Technology has 1400+ cases of RDF SRF alternative fuel preparation systems in the world.
In 2023, the cement industry market is sluggish, on the one hand, cement companies need to save costs from all aspects to tide over the difficulties;On the other hand, a number of carbon emission reduction policies and measures have been introduced, which has forced the cement industry to carry out a major change of "carbon reduction". The RDF SRF alternative fuel preparation technology can reduce the cost of coal and is an effective way to achieve "low-carbon, environmental protection and emission reduction".