1 Scope
This document specifies the method for calculating the energy efficiency of coal-water slurry gasification in a fluid bed.
This document applies to the energy efficiency calculation of gasification units using coal, petroleum coke. This document applies to the calculation of energy efficiency of coal-water slurry gasification units in a fluid bed with coal, petroleum coke, semi-coke, etc. as raw materials.
2 Normative reference documents
The contents of the following documents constitute the essential provisions of this document through the normative references in the text. Among them, note the date of the cited documents, only the corresponding version of the eight issues apply to this document; do not note the eight issues of the cited documents, the latest version (including all the revision sheets) apply to this document.
GB/T 2589 General rules for the calculation of comprehensive energy consumption
GB31571 Emission Standards for Pollutants in the Petrochemical Industry
3 Terminology and definitions
The following terms and definitions are applicable to this document.
3.1
coal-water slurry.
coal-water slurry
A slurry made from coal. water and a small amount of additives, processed to produce a fluid with a certain particle size distribution. Fluid with good flow and stability.
Note. Coal-water slurry is divided into coal-water slurry for fuel and coal-water slurry for gasification according to its application.
[Source: GB/T 18855- 2014, 3.1, with modifications]
3.2
Coal slurry preparationcoal water slurry preparation
The process of transporting raw coal for material chemistry to a coal mill and grinding it together with water and additives to obtain a qualified coal water slurry suitable for gasification.
3.3
entrained-flow coal-water slurry gasification
The process of gasification in which the medium carries the coal-water slurry and keeps it in a flowing state in the gasifier.
[Source: GB/T 31428- 2021, 5.5, with modifications]
3.4
Synthesis gas syngas
A raw or fuel gas with carbon monoxide and hydrogen as the main components.
[Source:GB/T 31428- 2021 ,5.9]
3.5
Effective syngas
The carbon monoxide and hydrogen in a syngas.
3.6
Recirculating cooling sailer
Water that is circulated by means of a heat exchanger or direct contact heat exchange to exchange the heat of the medium and is cooled down by a cooling tower.
3.7
Boiler feed water
After water treatment, the water quality is in line with the standard of the feed water into the boiler.
[Source: HG/T 3163- 1987 ,3101]
3.8
Desalinated water
Removed all the dissolved inorganic salts of the water.
[Source: HG/T 3163- 1987 ,3103, with modifications]
by-product steam
Steam of different temperature and pressure levels produced during the gasification or transformation process.
3.10
energy consumption eficiency for entrained- flow coal-water slurry gasification
The ratio of the total effective energy output to the total energy input for entrained-flow coal-water slurry gasification during the statistical reporting period.
4 Basic provisions
4.1 In the calculation of energy efficiency, the input and output energy without the use of the unified - energy conversion factor shall be in accordance with the provisions of Appendix A.
4.2 In the comparative evaluation of different air-bed coal-water slurry gasification process technologies (including radical cooling process, waste pot process, etc.), the benchmark for comparison is the hourly production of effective gas (CO+ H2) under standard conditions.
4.3 The calculation of input/output energy should be considered in accordance with normal operating conditions, while continuous utility consumption and intermittent utility consumption during normal production should be taken into account. The consumption or output under the conditions of start-up and stoppage, accident, fire fighting, temporary blowing, etc. shall not be taken into account. Intermittent consumption or output during normal production is discounted to an average value and then included. Exhaust gas, waste liquids and waste residues from the production system that are not recycled, have no measured calorific value and are not used as energy shall not be counted as energy output.
4.4 The raw coal used for gasification is based on a dry basis, and the energy carried by the raw coal, fuel gas or fuel oil shall be calculated according to the low level of calorific value.
4.5 The energy conversion factor of oxygen and nitrogen shall be converted in accordance with GB/T2589, and the energy conversion factors of oxygen and nitrogen products of different pressure levels shall be referred to in Appendix B.
4.6 The requirements of external sewage discharge should be considered in accordance with the energy input, in order to meet the indicators of wastewater discharge specified in GB31571 as the benchmark, if it cannot be met, it should be considered to meet the requirements after wastewater treatment, and calculate the corresponding energy consumption in the wastewater treatment process.
4.7 The wastewater from other devices used for pulping should be based on the wastewater discharge index specified in GB31571, and the part of the wastewater index that exceeds it should be considered to meet the requirements after wastewater treatment, and the corresponding energy consumption in the wastewater treatment process should be calculated, and the energy consumption should be taken as the output item.
4.8 When pulp is made from sludge and other hazardous solid waste sent from other units, the energy consumption per unit of hazardous waste used for pulp making shall be considered when the waste is treated in the traditional way, and the energy consumption shall be taken as the output item.
4.9 See Appendix C for the calculation of energy efficiency of coal slurry gasification in a fluid bed.
5 Calculation
5.1 Calculation range
As shown in Figure 1, the air bed coal-water slurry gasification unit includes: coal-water slurry preparation and coal-water slurry transport, gasification and slagging of crude syngas preliminary washing, process black water treatment and grey water use and crude syngas energy recovery part (including crude syngas excitation cooling, radiation waste pot cooling, subsequent units can use compression work, etc.). Coarse synthesis gas conversion, etc.
5.2 Gasification units Total energy input
The energy input statistics include: raw coal, oxygen, fuel gas/oil, electricity, water vapour, fresh water. Circulating cooling water, demineralised water, boiler feed water. External wastewater, compressed air, instrument air, nitrogen and other energy-consuming substances and pressure compensation power consumption, excluding energy consumption for start-up and stoppage, accidents, fire-fighting, temporary purging, etc.
5.3 Total energy output of the gasification unit
The energy output statistics include: conversion of synthesis gas (including crude synthesis gas energy recovery), high-pressure flash gas, water vapour by-production, wastewater (using wastewater from other units to make coal slurry), external heat exchange output, etc.
5.4 Energy efficiency calculations
