How to reduce the consumption of synthetic ammonia

Here is an article on the consumption of synthetic ammonia; I hope it will be useful to you, OP. China Nitrogen Fertilizer Industry Association I. Principles for Statistics on Energy Consumption in Ammonia Synthesis 1. Indicator system for statistics on energy consumption in ammonia synthesis: ① Natural gas consumption per unit of ammonia produced (cubic meters/ton) ； ②Electricity consumption per unit of synthetic ammonia produced (kWh/ton) ； ③Standard raw coal consumption per unit of synthetic ammonia produced (kilograms of standard coal per ton), calculated based on 7,000 kcal/kg as the value for standard coal ； ④Standard fuel coal consumption per unit of synthetic ammonia produced (kilograms of standard coal per ton), calculated based on 7,000 kcal/kg as the value for standard coal ； ⑤Comprehensive energy consumption per unit of synthetic ammonia (kilograms of standard coal per ton), calculated based on 7,000 kcal/kilogram as the equivalent for standard coal ； 2. The energy consumption for ammonia synthesis refers to the amount of energy actually consumed in the production of ammonia products, or the energy required for such production; it should neither be undercounted nor double-counted. Therefore, when calculating energy consumption, it should include not only the consumption of the production system but also that of the auxiliary and supporting production systems.     3. The consumption of individual energy sources refers to the amount of energy that is actually purchased and used in the production of synthetic ammonia. For example, briquette coal purchased alongside lump coal – although it is not fed into the furnace – is still part of the raw coal purchased, and therefore should be included in the statistics on raw coal consumption. However, the unused fly ash can be deducted from the overall energy consumption when it is exported. ②        The energy generated during the ammonia synthesis process (such as recycled coke, recycled carbon, coal slurry, combustible gases, etc.), since it is in a different state from when it was introduced into the system, should not be deducted from the individual energy consumption figures for the inputs; rather, it should be included in the category of energy output in the overall energy consumption calculation. 4. The returned coke, returned carbon, and fines screened out from lump coal used in blending are no longer counted repeatedly as raw material or fuel consumption. 5. The energy consumed for the safety and environmental protection measures that are essential in ammonia synthesis production should be included in the respective individual consumption figures. Such as: sulfur recovery, oil recovery, wastewater treatment, etc. 6. Multiple users sharing feed gas and utility services (steam, energy-consuming fluids, etc.), as well as enterprises engaged in combined alcohol, combined alkali, or combined power production, should reasonably share the costs associated with energy consumption. 7. The energy supplied by the ammonia synthesis system to other products or units outside the system shall be deducted from the total energy consumption as part of the energy exported. Waste gases, waste liquids, waste residues, etc. from ammonia synthesis systems that are not reused, for which no measurement of calorific value has been taken and which are not utilized as energy sources again (such as for road construction or building construction), shall not be included in the calculated energy output. II. Method for calculating energy consumption indicators for synthetic ammonia 1. Natural gas consumption per unit of synthetic ammonia 1.1 Calculation formula: Natural gas consumption per unit of synthetic ammonia (cubic meters/ton) = 10,000 × Total natural gas consumption for synthetic ammonia (10,000 cubic meters) / Synthetic ammonia production volume (tons) 1.2 Sub-item: Total natural gas consumption for synthetic ammonia includes the raw gas used in gas production, as well as the natural gas used to heat the conversion furnace tubes and auxiliary boilers, plus the natural gas used in steam boilers. The same calculation method is applied for producing ammonia using oilfield gas, coke oven gas, and refinery gas. 1.3 Numerator: Ammonia production volume (see Section 6 Ammonia Production Volume) (omitted below). 2.1 Formula for electricity consumption per unit of synthetic ammonia: Electricity consumption per unit of synthetic ammonia (kWh/ton) = 10,000 × Total electricity consumption for synthetic ammonia (10,000 kWh) / Synthetic ammonia production volume (tons). 2.2 Sub-item: Total electricity consumption for synthetic ammonia. The total electricity consumption for synthetic ammonia includes the electricity used by the synthetic ammonia production system as well as auxiliary and supporting production systems, plus the losses within the facility boundaries. It shall be based on the meter reading. 2.2.1 The total electricity consumption for ammonia synthesis shall include: 2.2.1.1 the electricity used in various processes such as material transportation at the raw material yards and warehouses (coal, coke, oil, gas), preprocessing (crushing of raw coal, production of briquettes, etc.), gas generation, purification, compression, ammonia synthesis, operation of ice makers, transportation to the ammonia storage facility, and auxiliary boilers. Electricity consumption for workshop lighting, safety ventilation, heating, air conditioning, exhaust and cooling systems, workshop offices, analysis and testing equipment, as well as baking motors in the various processes mentioned above. 2.2.1.2 Power consumption for operations during planned major, medium, and minor repairs as well as repairs due to accidents (such as lifting and welding), as well as the power used for processes such as ignition, furnace heating, temperature raising, hot standby, and purging that occur during startup and shutdown procedures resulting from maintenance work (including major repairs). 2.2.1.3 The electricity consumed in the preparation, extraction, and transportation of various energy-carrying media used in ammonia synthesis (such as primary water, circulating water, chemically softened water, deoxygenated water, oxygen, nitrogen, compressed air, etc.). 2.2.1.4 Power consumption for waste treatment in the ammonia synthesis process (sulfur recovery, oil recovery, wastewater treatment, etc.). 2.2.1.5 Electricity consumption of industrial boilers (such as power used by exhaust fans, blowers, water supply systems, and cooling circulation pumps). If the boiler also supplies steam to other products, the steam consumption required for ammonia synthesis should be reasonably allocated to the electricity cost associated with ammonia production. 2.2.1.6 The electricity consumption for processes such as mechanical, electrical, and instrumentation maintenance as well as metal processing, along with the electricity used for workshop lighting, ventilation, cooling, and workshop offices, should all be allocated reasonably based on their actual share of the maintenance tasks and processing work related to the ammonia production system. 2.2.1.7 Enterprises that produce ammonia, hydrazine, hydrazine oxide, and carbon ammonium should reasonably share the electricity consumed by them. 2.2.1.8 Additional power is provided for ice makers and tank filling for liquid ammonia as a commodity. 2.2.1.9 Other electricity consumption for ammonia synthesis production. 2.2.2 The total electricity consumption for ammonia synthesis does not include: 2.2.2.1 Electricity used for expansion and technical improvement projects. 3 Standard raw coal consumed per unit of synthetic ammonia (converted to standard coal at 7,000 kcal/kg). 3.1 Calculation formula: Standard raw coal consumed per unit of synthetic ammonia (kg/ton) = 1000 × Total standard raw coal consumed for synthetic ammonia (tons) / Synthetic ammonia production volume (tons). 3.2 Sub-item: Total standard raw coal consumed for synthetic ammonia (tons) = Sum of amounts for each batch (tons). 3.2.1 The actual raw coal (or coke) refers to the coal fed into the gas generation furnace (such as anthracite, coke, briquettes, bituminous coal, lignite, etc.); when lump coal is used as the raw material, this includes the fine coal particles screened out before being fed into the furnace. The actual measured value shall prevail. 3.2.2 The applied lower heating value refers to the heat effect when, under certain temperature conditions, the water vapor in the products of complete combustion remains in gaseous state. Applied lower heating value = Higher heating value measured by the oxygen bomb calorimeter – Amount of steam produced during combustion × Heat of vaporization of steam3.2.3 Principles for allocation and deduction3.2.3.1 When gases emitted during the production of synthetic ammonia are reused as fuel (such as tank gas, purge gas, etc.), they cannot be deducted from the relevant sub-items ； 3.2.3.2 The return of fume (return of carbon) is no longer counted as consumption, and those not reused in the furnace are also not deducted. 3.2.3.3 In the production of synthetic ammonia, when the process gases are used as raw materials for other products or to produce other goods alongside synthetic ammonia, the consumption of coal as a raw material should be allocated reasonably. (For combined alcohol, combined alkali, and combined electricity, refer to the methods for allocating energy consumption in ammonia synthesis along with methanol production, the methods for allocating energy consumption in ammonia synthesis along with alkali production, and the methods for allocating energy consumption in ammonia synthesis along with electricity production.) The standard fuel coal consumption per unit of ammonia synthesized is calculated based on 7,000 kcal/kg as the equivalent value of standard coal. 4.1 Calculation formula: Standard fuel coal consumption per unit of ammonia synthesized (kg/ton) = Total standard fuel coal consumption (kg) / Ammonia production volume (tons). 4.2 Sub-item: Total standard fuel coal consumption (kg) = Sum of the consumption per batch (kg). 4.2.1 The lower heating value used in this calculation is the same as that specified in 5.2.2. 4.2.2 The total standard fuel coal consumption for ammonia synthesis refers mainly to the fuel coal used to generate steam to meet the steam demands of the ammonia synthesis system as well as various auxiliary and supporting production systems. The amount of purchased steam should be converted to standard fuel coal based on the inlet enthalpy and boiler efficiency. 4.2.2.1 The steam consumption of the production system includes steam used in the production processes and during startup and shutdown operations across all stages, from gas generation, purification, compression, ammonia synthesis, to the ammonia storage facility (including steam required for starting up the plant after major, medium, or minor repairs), as well as steam used for insulating the equipment and pipelines in these processes, and for heating workshops, laboratories, and office spaces. 4.2.2.2 The steam consumption of auxiliary and supporting production systems includes all steam used for heating in coal ball manufacturing, deoxygenated water preparation, raw material and fuel storage areas and preprocessing processes, the coal ball workshop, the on-site boiler room, as well as the mechanical, electrical, and instrumentation maintenance workshops and the offices associated with these workshops. It also includes steam used for replacement and cleaning during planned major, medium, and minor repairs as well as in case of emergencies, as well as steam required for safe production, treatment of waste materials, and environmental protection processes. 4.2.2.3 When steam is used solely for ammonia synthesis, both the fuel coal consumption and the steam volume are included in the ammonia synthesis consumption ； When steam is used for multiple products, the fuel coal consumption should be allocated reasonably. (The allocation of consumption for combined alcohol, combined alkali, and combined electricity is specified in the methods for allocating energy consumption in ammonia synthesis with methanol production, those for ammonia synthesis with alkali production, and those for ammonia synthesis with electricity production.) 4.2.2.4 Carbon returned from combustion, slag, coal gangue, and fine coal screened out from lump coal used as supplementary fuel in boilers are not included in the fuel consumption; carbon recovered from the residues left after boiler combustion is also not deducted from the consumption figures. 4.2.2.5 The steam generated as a by-product of the ammonia synthesis process is used internally by this system and is not counted as consumption; steam that is vented or discharged is also not deducted from the fuel coal consumption. 5.2 Comprehensive energy consumption per unit of synthetic ammonia produced: The formula is as follows: Comprehensive energy consumption per unit of synthetic ammonia produced (kilograms of standard coal per ton), calculated using 7,000 kcal/kg as the conversion factor to standard coal = Natural gas consumption per unit of synthetic ammonia (converted to standard coal) + Electricity consumption per unit of synthetic ammonia (converted to standard coal) + Standard raw coal consumption per unit of synthetic ammonia + Standard fuel coal consumption per unit of synthetic ammonia – Energy output per unit of synthetic ammonia (converted to standard coal). 5.2.1 Natural gas consumption per unit of synthetic ammonia (kilograms of standard coal per ton) = Natural gas consumption per unit of synthetic ammonia (cubic meters per ton, under standard conditions) × Lower heating value of natural gas (kcal per cubic meter) / 7,000 (kcal per kilogram). 5.2.1.1 The natural gas consumption per unit of synthetic ammonia is calculated in accordance with Section 5.2.1.2. The lower heating value of gases such as natural gas can be determined through analysis of the gas composition. Lower heating value = (2579×H2%) + (3018×CO%) + (5585×H2S%) + (8555×CH4%) + (15226×C2H6%) + (21795×C3H8%) + (28338×C4H10%) + (34890×C5H12%) + (14107×C2H4%) + (20541×C3H6%) + (27111×C4H8%) + (33528×C5H10%) (kilocalories per standard cubic meter). 5.2.2 Electricity consumption per unit of synthetic ammonia (kilograms of standard coal per ton) = Electricity consumption per unit of synthetic ammonia (kilowatt-hours per ton) × 0.1229 kilograms of standard coal/kilowatt-hour. 5.2.2.1 Electricity consumption per unit of synthetic ammonia is the same as that in Section 2. 5.2.2.2 0.1229 kilograms of standard coal/kilowatt-hour = 860 (kilocalories/kilowatt-hour) / 7000 (kilocalories/kilogram). 5.2.3 Standard raw coal consumption per unit of synthetic ammonia is as stated in Section 3. 5.2.4 Standard fuel coal consumption per unit of synthetic ammonia is as stated in Section 4. 5.2.5 Energy output per unit of synthetic ammonia (converted to standard coal at 7000 kilocalories/kilogram). 5.2.5.1 Energy output from synthetic ammonia refers to the energy that the synthetic ammonia system supplies to external parties for use in other products or systems. Waste gases, waste liquids, waste residues, etc. from ammonia synthesis systems that are not reused, for which no measurement of calorific value has been taken and which are not utilized as energy sources again (such as for road construction or building construction), shall not be included in the calculated energy output. 5.2.5.2 Regulations for calculating the energy output in terms of standard coal: (1) For synthetic ammonia off-gas, vent gas, and stripping gas that are used as energy sources (raw materials or fuels) for other products or systems (including use as fuel gas for domestic purposes), the calorific value shall be calculated based on the actual composition of the fuel gas (using the same calculation method as 5.2.1.2). (2) The materials discharged from ammonia synthesis gas production (such as peat coal, coal ash, coke ash, slag, etc.) are indeed used as energy for other products or facilities (e.g., in the production of honeycomb coal, coal balls, and bricks and tiles), and standard coal is calculated based on their measured lower heating value (7,000 kcal/kg). (3) When waste heat (or residual pressure) from the ammonia synthesis system is utilized to generate electricity and steam, the electricity produced and the steam generated are supplied for use in other products or devices; the electricity is valued at 0.1229 kilograms of standard coal per kilowatt-hour, while the steam is valued based on its enthalpy under the temperature and pressure conditions at the point of exit. (4) Utilizing the waste heat from ammonia synthesis to preheat materials (or process water) for use in other products or units (based on the recovered thermal energy). The formula for calculating the recovered heat energy is: Q = D × C × (T_out – T_in). Where: D is the amount of material to be preheated (in kilograms); C is the specific heat capacity of the material to be preheated (in kcal/kg•°C); T_out and T_in are the temperatures of the material before and after entering the ammonia synthesis system ； 6 Ammonia production: The ammonia production is calculated in terms of physical volume, without converting it to 100% pure form. The ammonia production volume includes: the consumption by various ammonia-using units within the plant ； Amount of liquid ammonia sold ； Internal consumption in the ammonia synthesis process (for purification and desulfurization) ； Amount of ammonia recovered from ammonia tank vent gas and synthesis tower off-gas (calculated as 100% based on the recovered product as ammonia-containing material) ； The ammonia production volume does not include: the ammonia used for the chiller’s own operations (losses) ； Purification; ammonia content in the ammonia recovered through ammonia desulfurization ； The ammonia content in the ammonia water coming out of the carbonization cleaning tower and the recovery tower. The ammonia synthesis production volume should be based on instrument measurements ； For enterprises that have not installed liquid ammonia meters, the production volume of synthetic ammonia is calculated based on the output of the final nitrogen-containing products. The production volume of synthetic ammonia is calculated by eliminating the method based on the ammonia tank level gauge and by using the quota for ammonia consumption in ammonia-based products.     6.1 Instrumentation for measurement: When using instruments to measure the production of liquid ammonia, the liquid ammonia must pass through an intermediate tank to have the gases dissolved in it removed under reduced pressure, and temperature and pressure adjustments must be made to ensure accurate measurement. When a company has both a total ammonia meter and separate meters for each user, the ammonia produced must balance with the amount used; there should be no artificial discrepancy where production is higher than consumption.     6.1.1 The total ammonia meter is installed in front of the ammonia storage area: Synthetic ammonia production (tons) = Reading on the total ammonia meter + Amount of ammonia recovered from blowdown, purge, and vent gases. 6.1.2 After the total ammonia meter is installed in the ammonia storage area: Synthetic ammonia production (tons) = Reading on the total ammonia meter + Amount of ammonia used internally + Amount of liquid ammonia sold as a product + Amount of ammonia recovered from vented, purified, and released gases + (Ending inventory in ammonia tanks – Starting inventory in ammonia tanks). 6.1.3 When the sum of the ammonia metering sub-tables for each user is used as the ammonia production volume: it includes the value indicated for domestic use ammonia and commercial liquid ammonia + the amount of ammonia recovered from blown-off, stripped, and vented gas) + (ending inventory of ammonia tanks – starting inventory of ammonia tanks). The amount of ammonia recovered from the off-gases, purge gases, and vent gases refers to the amount of ammonia that is recovered from the off-gases of the synthesis tower, the purge gases from the intermediate tank, and the vent gases from the ammonia tank for reuse or sale within the system.    6.2 The ammonia synthesis production is calculated based on the final nitrogen-containing product. When calculating the ammonia synthesis production based on the final nitrogen-containing product, the ammonia utilization rate for various solid fertilizers such as urea, ammonium bicarbonate, **, ammonium sulfate, and ammonium chloride, as well as concentrated nitric acid, is specified at 92% ； The ammonia utilization rate of ammonia water is 96%. The output of synthetic ammonia [in tons] = amount of liquid ammonia for sale (in tons) + amount of ammonia used internally (in tons) + [amount of solid fertilizer with 100% nitrogen content (in tons) + amount of solid fertilizer with 100% nitrogen content but of inferior quality (in tons)] × 1.32161 + ×1.04167. Where: 1.32161 = 1 /0.82245 /0.92; 0.82245 is the molecular weight of nitrogen divided by the molecular weight of ammonia, representing the theoretical nitrogen content in ammonia. 1.04167 = 1 /0.96. 6.2.1 The amount of liquid ammonia for sale is determined based on the amount packaged or loaded onto vehicles.     6.2.2 Ammonia consumption for own use. When each user is equipped with an ammonia meter, the amount of ammonia used for own consumption is based on the values indicated by the meter ； When there is no metering for individual users, the regulations and calculation formulas for ammonia used for internal purposes are as follows: (a) For the copper-washing process, the amount of ammonia used for internal purposes is 0.5% of the total ammonia volume. Amount of ammonia used for internal purposes (in tons) = Synthetic ammonia production × 0.5%. (b) For the process where alkali washing is replaced by ammonia washing after copper washing, the amount of ammonia used for internal purposes is also 0.5% of the total ammonia volume. Amount of ammonia used for internal purposes (in tons) = Synthetic ammonia production × 0.5%. (c) In the desulfurization process, the amount of ammonia used for internal purposes is 1% of the total ammonia volume.         Ammonia used for desulfurization (tons) = Ammonia production volume × 1%. Calculate only the amount of ammonia used for one of these three purposes; if none of them apply, then no ammonia used for internal purposes should be calculated. Additionally, ammonia consumption in other forms cannot be counted as ammonia used for internal purposes. 6.2.3 The ammonia content derived from ammonia water includes qualified agricultural ammonia and industrial ammonia produced from the gas blown out of the synthesis tower, the gas released from intermediate tanks, and the gas vented from ammonia tanks; it also includes unqualified ammonia with an ammonia content of over 10% that has been sold ； The ammonia content calculated from ammonia water does not include ammonia water obtained through purification (copper washing) and desulfurization recovery, as well as ammonia water coming from carbonization cleaning towers and recovery towers. It also does not include the ammonia used for internal purposes in purification (copper washing) and desulfurization processes, nor the ammonia that is discharged, whether it is of qualified or unqualified quality. 6.3 When producing synthetic ammonia from various raw materials, the amount of ammonia produced must be determined accordingly. Enterprises that produce synthetic ammonia using multiple raw materials shall break down the total output of synthetic ammonia by raw material when reporting it. The determination of the amount of synthetic ammonia produced from various raw materials should be based on the volume of gas generated by each raw material as well as the composition of its useful gas components, within the total amount of ammonia. The calculation formula is: Amount of synthetic ammonia produced from a certain raw material = Total amount of synthetic ammonia produced × 7. The output of nitrogen fertilizers refers to chemical fertilizers that contain nitrogen, an essential nutrient for crops.     The main types of nitrogen fertilizers include urea, ammonium bicarbonate, ammonium chloride, ammonium sulfate, **, calcium cyanamide, ammonia water, etc., as well as compound fertilizers containing nitrogen, such as nitrate phosphate fertilizers and ammonium phosphate fertilizers. Its pure content should be calculated on the basis of the actual nitrogen content, with the yield determined as 100%. The nitrogen fertilizer production (expressed as 100% nitrogen) is the sum of the qualified physical quantities of each type of nitrogen fertilizer, multiplied by their actual nitrogen content (%). Where the content of active ingredients is expressed on a dry basis, the calculation should involve deducting the moisture content from the actual mass, and then multiplying by the actual dry basis content determined through analysis. Calculation methods for major types of nitrogen fertilizers: 7.1 For urea (scientific name: carbamidine, NH2CONH2), the pure nitrogen content is calculated as follows: Urea (100% pure nitrogen) = sum of values from various batches. 7.2 For ammonium bicarbonate (NH4HCO3), the pure nitrogen content is calculated as follows: Ammonium bicarbonate (100% pure nitrogen) = sum of values from various batches. 7.3 For ammonium chloride (NH4Cl), the pure nitrogen content is calculated as follows: Ammonium chloride (100% pure nitrogen) = sum of values from various batches. 7.4 For **(NH4NO3), the pure nitrogen content is calculated as follows: ** (100% pure nitrogen) = sum of values from various batches. 7.6 Nitrogen content in calcium cyanamide (scientific name: CaCN2): The nitrogen content in calcium cyanamide (expressed as 100% pure nitrogen) = the sum of values from all batches. 7.7 Nitrogen content in ammonia water (NH4OH): The nitrogen content in ammonia water (expressed as 100% pure nitrogen) = the sum of values from all batches. 7.8 Nitrogen content in compound (mixed) fertilizers: When calculating the nitrogen content of nitrogen-containing compound (mixed) fertilizers, any nitrogen derived from liquid ammonia or urine – whether purchased or produced internally – must be counted as 100% pure nitrogen in the total nitrogen content. The nitrogen comes from the production of finished nitrogen fertilizers (urea, ammonium chloride, ammonium bicarbonate, ammonium sulfate, etc.), with the nitrogen fertilizer production being calculated without duplication.