GB/T 35170-2024Combustible material preprocessed from CMSW for co-processing in cement kiln (English PDF)

1 Scope

The document lays down the grading requirements, the grading code, the test methods, the inspection rules and the transport and storage of the combustible material preprocessed from municipal solid waste that is co-processed in a cement kiln.

It applies to the pattern in which household waste is processed before being disposed of in a cement kiln. It does not apply to the pattern in which waste goes into the kiln untreated.

The normative references are GB/T 176 on methods of chemical analysis of cement, GB/T 214 on the determination of total sulfur in coal, GB 4915 on emission of air pollutants from the cement industry, GB/T 6003.2 on perforated plate test sieves, GB 30485 on pollution control for the co-processing of solid waste in cement kilns, GB/T 30760 on the technical rules for that co-processing, GB/T 34615 on methods for testing the combustion characteristics of the material, GB/T 35171 on its sampling and sample preparation, CJ/T 96 on general methods for testing the chemical characteristics of household waste, and CJ/T 313 on the sampling and analysis of household waste.

3 Terms and definitions

The terms and definitions of GB 30485 and GB/T 30760 apply, together with one term defined here.

3.1 combustible material preprocessed from municipal solid waste, abbreviated CMSW: the combustible material obtained by preprocessing household waste of a known origin, able to supply a certain quantity of heat during co-processing. A note adds that the material does not include the hazardous wastes of the National Catalogue of Hazardous Wastes.

4 Grading requirements

4.1 Net calorific value as received. The material is graded on its net calorific value as received into five grades. Grade 1 is a net calorific value of not less than 25 MJ/kg, grade 2 not less than 20 MJ/kg, grade 3 not less than 15 MJ/kg, grade 4 not less than 10 MJ/kg and grade 5 not less than 6 MJ/kg.

4.2 Chlorine content on an air dried basis. Three grades: grade 1 not more than 0.5 percent, grade 2 not more than 1.0 percent, grade 3 not more than 2.0 percent.

4.3 Moisture content as received. Three grades: grade 1 not more than 10 percent, grade 2 not more than 20 percent, grade 3 not more than 40 percent.

4.4 Ash on an air dried basis. Three grades: grade 1 not more than 10 percent, grade 2 not more than 20 percent, grade 3 not more than 50 percent.

4.5 Particle size as received. Three grades, expressed as cumulative residue on a round-hole sieve: grade 1, not more than 15 percent on the 10 mm sieve; grade 2, not more than 20 percent on the 50 mm sieve; grade 3, not more than 20 percent on the 100 mm sieve.

5 Grading code

The material is graded on the five indicators net calorific value as received, chlorine content on an air dried basis, moisture content as received, ash on an air dried basis and particle size as received. The five carry equal weight, so that no single grade decides the code.

The grading code has to be entered in the performance parameter table of Annex A. Figure 1 shows the structure of the code, which strings the five indicator symbols each followed by its grade number, joined by hyphens.

The worked example given in the document is a material tested and calculated as follows: net calorific value as received 12, chlorine content on an air dried basis 0.8 percent, moisture content as received 30 percent, ash on an air dried basis 25 percent, particle size as received a cumulative residue of 18 percent on the 50 mm round-hole sieve. Its grading code is grade 4 for calorific value, grade 2 for chlorine, grade 3 for moisture, grade 3 for ash and grade 2 for particle size. The unit printed against the calorific value of the example is kJ/kg, which does not agree with the MJ/kg of 4.1; the figure is reported here as it is printed.

6 Test methods

6.1 Net calorific value as received. The gross calorific value as received is determined according to GB/T 34615 and converted to the net calorific value as received through the moisture content, by formula (1). The formula was too badly damaged in the extraction to be reproduced here; its legend is given instead. Qnet,ar is the net calorific value as received, in kilojoules per kilogram; 0.93 is an empirical constant; Qgr,ar is the gross calorific value as received, in kilojoules per kilogram; 24.4 is the constant for the heat of condensation of water, in kilojoules per kilogram; and Mar is the moisture content as received, as a percentage.

6.2 Chlorine content on an air dried basis is determined according to CJ/T 96.

6.3 Moisture content as received is determined according to CJ/T 313. The test portion is 500 g plus or minus 2 g, dried at 105 degrees C for 9 h to 10 h, the test being completed within 24 h of the sample being sealed. The tolerance printed on the drying temperature came out of the extraction as a plus sign followed by 5 degrees C and could not be read with certainty; it is not reproduced here.

6.4 Ash on an air dried basis is determined according to GB/T 34615.

6.5 Particle size as received is determined according to Annex B.

7 Inspection rules

7.1 Batching and sampling. Before release from the works the material is batched and sampled by the region the waste comes from; a batch does not exceed 700 t and each batch is one sampling unit. Sampling follows GB/T 35171, and not less than 40 kg is taken from each batch.

7.2 Inspection. The scope of the works inspection is everything laid down in Clause 5. The scope of the type inspection is everything laid down in Clause 5 together with every item of Annex A. A type inspection has to be carried out where the raw material or the process changes appreciably in a way that may affect the properties of the product; where a new product is being trial-produced or production resumes after a long stoppage; where the works inspection result differs appreciably from the last type inspection; and, in normal production, once every 6 months.

7.3 Rules of judgement. A result meeting the requirements of Clause 5 is a conforming product. A result failing any one of the indicators of Clause 5 is a non-conforming product.

7.4 Inspection report. The report has to carry the batch number, the grading code, the items inspected and any other technical requirement agreed in the contract.

7.5 Release from the works. The material may be released only where every technical indicator of the works inspection is met. On release the supplier has to provide the works inspection report and the relevant content of Annex A.

7.6 Delivery and acceptance. In preparing, delivering and accepting the material the user should draw up protective measures suited to the environment and to the process used, and make sure that the pollutants emitted when the material burns in the combustion installation satisfy GB 4915 and GB 30485. Acceptance of quality on delivery rests on the test result of the physical sample drawn, or on the supplier's inspection report for the same batch; which of the two is used is agreed between the parties and noted in the contract, and the supplier has the duty of telling the buyer the method of acceptance. Where there is no written contract, or the contract does not name the method, the supplier has to write on the invoice that acceptance rests on the works inspection report for the same batch. Where acceptance rests on the physical sample, the two parties sample and seal jointly before dispatch or at the place of delivery; sampling follows GB/T 35171, 80 kg is taken and divided into 2 equal parts, one kept by the seller for 10 d and the other tested by the buyer by the items and methods of this document. Where within those 10 d the buyer finds the product non-conforming and the seller objects, the part kept by the seller is sent for arbitration testing to a qualified body both parties accept. The moisture content as received is not an item of arbitration testing.

8 Transport and storage

During transport and storage the material has to be handled so as to reduce the effect of its odour on the environment.

B Annex B (normative) Method for testing particle size

B.1 Apparatus. The test sieves conform to GB/T 6003.2 and are round-hole sieves of nominal aperture 10 mm, 50 mm and 100 mm. The balance has a range of not less than 10 kg and a scale interval of not more than 10 g. The mechanical sieving machine should be a percussion type standard shaker, with an oscillation of 220 plus or minus 10 per minute and a percussion of 150 plus or minus 10 per minute.

B.2 Sample preparation. Sampling follows GB/T 35171, the quantity being fixed by eye from the particle size of the sample: where the size is near 25 mm the minimum is 1 kg; where it lies between about 25 mm and 150 mm the minimum is 2 kg; where it exceeds 150 mm the minimum is 5 kg. Sample preparation follows GB/T 35171, and the moisture content of the sample has to be less than 20 percent.

B.3 Procedure. The 100 mm, 50 mm and 10 mm sieves are stacked in that order on the pan. Depending on the size of the sieves the sample as received may be split into several sub-samples; the total mass is weighed accurately and the result kept to the nearest whole number. The shaker is run for 5 min, then the 100 mm sieve is taken off and shaken to and fro by hand while the frame is tapped lightly at 120 taps per minute, the sieve being turned 90 degrees in the same direction every 30 taps so that the sample spreads evenly, with no loss of sample permitted. The end point is reached when the sample passing the mesh in one minute is not more than 0.5 percent of the total mass. The residue is weighed accurately and what has passed is transferred without loss to the next sieve. The remaining sieves are worked in the same way, with the same end point, and each residue weighed in turn.

The frame is not to be struck before the end point is reached. Once the end point is reached the mesh has to be cleaned promptly and kept clear, and what is cleaned off counted in with the residue. The change in total mass between the start and the end of the test has to stay within 2 percent, failing which the test is repeated.

B.4 Calculation. The percentage residue on each sieve is calculated by formula (B.1) and kept to the nearest whole number. In the legend, R is the percentage residue on the sieve concerned; mi is the mass of the residue on that sieve, in grams; and m is the total mass of the sample, taken as the accumulated total mass after the test, in grams.

Note on the printed English title Note on the printed English title

The English title is given here exactly as printed on the cover of the document: Combustible material preprocessed from CMSW for co-processing in cement kiln. The only change made is to the hyphens, which the extraction returned as a typographic variant.

The reader should be aware that the abbreviation CMSW is defined in 3.1 of the document itself as combustible material preprocessed from municipal solid waste, that is, as the product the title is naming, so that the printed title reads back on itself where MSW, municipal solid waste, would be the raw material meant. This is a matter of the terminology as issued by the Chinese body, not a printing slip, and it has therefore been left as it stands rather than silently corrected.

Tables not reproduced Tables not reproduced

Table A.1, the performance parameter table of Annex A, is a blank form and came out of the extraction with the column headings, the row labels, the footnote markers and the blank entry fields detached from one another, so that no row can be paired with its heading with confidence. Its numeric content is not reproduced here.

What Table A.1 fixes is the record to be kept for a consignment. It carries the grading code and the origin of the material, described by the place the feedstock came from, rural or urban, office building or shopping centre and the like. It then records the physical properties, the form, chosen among lump, flake, powder and fluff, the bulk density, determined according to CJ/T 313 with a vessel of not less than 10 L effective capacity, and the particle size as cumulative residue on the 10 mm, 50 mm and 100 mm round-hole sieves, other apertures being allowed as well. It then records the indicators of the material, namely net calorific value as received, gross calorific value as received, chlorine content, moisture content, ash and volatile matter, the gross calorific value and the volatile matter being marked as reference indicators. It finally records the elemental analysis of the ash, namely total sulfur, mercury, lead, cadmium, total chromium, arsenic, and the contents of silicon dioxide, aluminium oxide, iron oxide, calcium oxide, magnesium oxide, potassium oxide and sodium oxide. Each indicator is entered with a characteristic or median value and a maximum, and with the test method used. A footnote explains that the characteristic value is generally the median or the 80 percent point of the element concerned and serves to describe the state of the material as agreed or as prescribed, and that the limit may be a maximum, a minimum, an 80 percent point or a median, agreed between producer and user. A further footnote directs the test methods: gross calorific value and volatile matter according to GB/T 34615, total sulfur according to GB/T 214, mercury, lead, cadmium, total chromium and arsenic according to CJ/T 96, and the oxides in the ash according to GB/T 176.