Method of dewatering brown coal

A process for steam dewatering of brown coal, using a plurality of autoclaves, each of which, in cyclic sequence among the autoclaves, repeats a batch process comprised of:

• (1) atmospheric pressure stage to unload the coal dewatered and to load the coal to be dewatered;
• (2) heating stage to heat and dewater said loaded coal;
• and
• (3) depressurizing stage to lower the interior pressure for said unloading of coal,
• wherein said heating stage comprises an initial steaming step Si, a first steaming step S1 after said step Si, and a second steaming step S2 immediately after said step Si and at the end of said heating stage, the autoclaves in both said steps S1 and S2 being supplied with fresh steam from an external source, the autoclave in said step Si is being connected to the autoclave in the said step S2, so that the steam flows from the latter to the former, thereby intensifying the steam ventilation already in the claim at said step S2, said batch operation being common to all of said used autoclaves both in the constitution of steps and in the length of its cycle time, 1/N of the one batch cycle time being the interval between each two autoclaves successive in the said cyclic sequence, and the total time of said steps S1 and S2 is equal to 1/N of the single batch cycle time, where N is the number of said autoclaves, whereby only one autoclave is supplied with fresh steam simultaneously, there being no intermediate steaming step between said step Si and said step S1, each of the said autoclaves at said step S1 being unconnected with any other autoclaves, and then each of said autoclaves at said step S2 is connected directly with the autoclave next in said cyclic sequence, thereby conducting said step Si in said next autoclaves.

A process for steam dewatering of brown coal, using a plurality of autoclaves, each of which, in cyclic sequence among the autoclaves, repeats a batch process comprised of:

• (1) atmospheric pressure stage to unload the coal dewatered and to load the coal to be dewatered;
• (2) heating stage to heat and dewater said loaded coal;
• and
• (3) depressurizing stage to lower the interior pressure for said unloading of coal,
• wherein said heating stage comprises an initial steaming step Si, a first steaming step S1 after said step Si, and a second steaming step S2 immediately after the said step S1 and at the end of the heating stage, the autoclaves in both the said steps S1 and S2 are supplied with fresh steam from an external source, the autoclave in the said step Si is connected to the autoclave in the said step S2, so that the steam flows from the latter to the former, thereby intensifying the steam ventilation at said step S2, said batch operation being common to all of said used autoclaves both in the constitution of steps and in the length of its cycle time, 1/N of the one batch cycle time being the interval between each two autoclaves successive in the said cyclic sequence, and the total time of said steps S1 and S2 is equal to 1/N of the single batch cycle time, where N is the number of said autoclaves, whereby only one autoclave is supplied with fresh steam simultaneously, there being a plurality of intermediate steaming steps between said step Si and said step S1, each of said autoclaves at said step S1 being connected with one or more autoclaves in series in accordance with said cyclic sequence, thereby conducting intermediate steaming steps in said connected autoclaves in series, and then at said steps S2 is connected with the autoclave next to said series via the said series, thereby continuing the intermediate steaming steps in said series autoclaves and conducting said step Si in said next autoclaves.

A process for steam dewatering of brown coal, using a plurality of autoclaves, each of which, in cyclic sequence among the autoclaves, repeats a batch process comprised of:

• (1) atmospheric pressure stage to unload the coal dewatered and to load the coal to be dewatered;
• (2) heating stage to heat and dewater said loaded coal;
• and
• (3) depressurizing stage to lower the interior pressure for said unloading of coal,
• wherein said heating stage comprises first and second steaming steps successive to this order at the final period of this stage to be supplied with fresh steam from an external source, and an initial steaming step under which the autoclave is connected with the other autoclave undergoing said second steaming step, thereby intensifying the steam ventilation at said second steaming step, wherein there is no intermediate steaming step between said initial steaming step and said first steaming step, each of the said autoclaves at said first steaming step being unconnected with any other autoclaves, and then at said second steaming step is connected directly with the autoclave next in said cyclic sequence, thereby conducting said initial steaming step in said next autoclaves, and there are two said condensate tanks for receiving and storing the hot water generated in said autoclaves and either of these said condensate tanks is only connected to said autoclaves only at said initial steaming step and the steaming step next to said step.

A process for steam dewatering of brown coal, using a plurality of autoclaves, each of which, in cyclic sequence among the autoclaves, repeats a batch process comprised of:

• (1) atmospheric pressure stage to unload the coal dewatered and to load the coal to be dewatered;
• (2) heating stage to heat and dewater said loaded coal;
• and
• (3) depressurizing stage to lower the interior pressure for said unloading of coal,
• wherein said heating stage comprises first and second steaming steps successive in this order at the final period of this stage to be supplied with fresh steam from an external source, and an initial steaming step under which the autoclave is connected with the other autoclave undergoing said second steaming step, thereby intensifying the steam ventilation at said second steaming step, said batch operation being common to all of said used autoclaves both in the constitution of steps and in the length of its cycle time, 1/N of the one batch cycle time being the interval between each two autoclaves successive in the said cyclic sequence, and the total time of said first and second steaming steps is equal to 1/N of the single batch cycle time, where N is the number of said autoclaves, whereby only one autoclave is supplied with fresh steam simultaneously, there being no intermediate steaming step between said initial steaming step and said first steaming step, each of the said autoclaves at said first steaming step being unconnected with any other autoclaves, and then at said second steaming step is connected directly with the autoclaves next in said cyclic sequence, thereby conducting said initial steaming step in said next autoclaves, there are two said condensate tanks for receiving and storing the hot water generated in said autoclaves, and either of these said condensate tanks is connected to said autoclaves only at said initial steaming step and in the steaming step next to said step.

A process for steam dewatering of brown coal, using a plurality of autoclaves, each of which, in cyclic sequence among the autoclaves, repeats a batch process comprised of:

• (1) atmospheric pressure stage to unload the coal dewatered and to load the coal to be dewatered;
• (2) heating stage to heat and dewater said loaded coal;
• and
• (3) depressurizing stage to lower the interior pressure for said unloading of coal,
• wherein said heating stage comprises first and second steaming steps successive in this order at the final period of this stage to be supplied with fresh steam from an external source, and an initial steaming step under which the autoclave is connected with the other autoclave undergoing said second steaming step, thereby intensifying the steam ventilation at said second steaming step, wherein there are a plurality of intermediate steaming steps between said initial steaming step and said first steaming step, each of said autoclaves at said first steaming step being connected with one or more autoclaves in series in accordance with said cyclic sequence, thereby conducting intermediate steaming steps in said connected autoclaves in series, and then at said second steaming steps is connected with the autoclave next to said series via the said series, thereby continuing the intermediate steaming steps in said series autoclaves and conducting said initial steaming step in said next autoclaves, and there are two said condensate tanks for receiving and storing the hot water generated in said autoclaves, and either of these said condensate tanks is connected to said autoclaves only at said initial steaming step and the steaming step next to said step.

A process for steam dewatering of brown coal, using a plurality of autoclaves, each of which, in cyclic sequence among the autoclaves, repeats a batch process comprised of:

• (1) atmospheric pressure stage to unload the coal dewatered and to load the coal to be dewatered;
• (2) heating stage to heat and dewater said loaded coal;
• and
• (3) depressurizing stage to lower the interior pressure for said unloading of coal,
• wherein said heating stage comprises first and second steaming steps successive in this order at the final period of this stage to be supplied with fresh steam from an external source, and an initial steaming step under which the autoclave is connected with the other autoclave undergoing said second steaming step, thereby intensifying the steam ventilation at said second steaming step, said batch operation being common to all of said used autoclaves both in the constitution of steps and in the length of its cycle time, 1/N of the one batch cycle time being the interval between each two autoclaves successive in the said cyclic sequence, and the total time of said first and second steaming steps is equal to 1/N of the single batch cycle time, where N is the number of said autoclaves, whereby only one autoclave is supplied with fresh steam simultaneously, there being a plurality of intermediate steaming steps between said initial steaming step and said first steaming step, each of said autoclaves at said first steaming step being connected with one or more autoclaves in series in accordance with said cyclic sequence, thereby conducting intermediate steaming steps in said connected autoclaves in series, and then at said second steaming steps is connected with the autoclave next to said series via the said series, thereby continuing the intermediate steaming steps in said series autoclaves and conducting said initial steaming step in said next autoclaves, and there are two said condensate tanks for receiving and storing the hot water generated in said autoclaves, and either of these said condensate tanks is connected to said autoclaves only at said initial steaming step and the steaming step next to said step.